WorldWideScience

Sample records for stabilized electric arcs

  1. Stabilization of electric-arc furnace dust in concrete

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Caldas de Souza

    2010-12-01

    Full Text Available Electric-arc furnace dust (EAFD is a by-product of steel production and recycling. This fine-grained material contains high amounts of zinc and iron as well as significant amounts of potentially toxic elements such as lead, cadmium and chromium. Therefore, the treatment and stabilization of this industrial residue is necessary. Concrete is a well-known suitable environment for stabilization/solidification of materials which have leachable elements in need of fixation. The effect of the EAFD content on the mechanical and chemical performance of Portland cement concrete is investigated in this paper. The effect of the EAFD content on the setting time of cement slurry was also analyzed. The axial compressive strength of the concrete samples increases with the EAFD addition in the range of 10 to 20 wt. (% EAFD; also the tensile strength increases with the EAFD addition. An increase in EAFD content significantly increases the setting time of the concrete. The acetic acid leaching and water solubilization tests indicate low mobility of the potentially toxic elements from the EAFD concrete composite. The results of the immersion tests show that the addition of EAFD to the concrete seems to reduce chloride penetration, which may help prevent pitting corrosion in reinforced concrete.

  2. Computer Modeling of Radiative Transfer in Hybrid-Stabilized Argon–Water Electric Arc

    Czech Academy of Sciences Publication Activity Database

    Jeništa, Jiří; Takana, H.; Nishiyama, H.; Křenek, Petr; Bartlová, M.; Aubrecht, V.

    2011-01-01

    Roč. 39, č. 11 (2011), s. 2892-2893 ISSN 0093-3813 Institutional research plan: CEZ:AV0Z20430508 Keywords : Divergence of radiation flux * hybrid-stabilized electric arc * mass flow rate * partial characteristics * radiation flux Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.174, year: 2011 http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=27

  3. A comparative numerical study of hybrid-stabilized argon–water electric arc

    Czech Academy of Sciences Publication Activity Database

    Jeništa, Jiří; Takana, H.; Nishiyama, H.; Bartlová, M.; Aubrecht, V.; Křenek, Petr; Sember, Viktor; Mašláni, Alan

    2011-01-01

    Roč. 182, č. 9 (2011), s. 1776-1783 ISSN 0010-4655. [Computer Physics Communications Special Edition for Conference on Computational Physics. Trondheim, 23.06.2010-26.06.2010] R&D Projects: GA ČR GA202/08/1084 Institutional research plan: CEZ:AV0Z20430508 Keywords : hybrid-stabilized electric arc * mass flow rate * net emission coefficients * partial characteristics * SIMPLER iteration procedure * LU-SGS algorithm Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.268, year: 2011 http://www.sciencedirect.com/science/article/pii/S0010465511000269

  4. The Influence of Turbulence on Characteristics of a Hybrid-Stabilized Argon-Water Electric Arc

    Czech Academy of Sciences Publication Activity Database

    Jeništa, Jiří; Takana, H.; Nishiyama, H.; Bartlová, M.; Aubrecht, V.; Křenek, Petr

    2013-01-01

    Roč. 8, č. 2 (2013), s. 435-447 ISSN 1880-5566. [Ninth International Conference on Flow Dynamics (ICFD2012). Sendai, 19.09.2012-21.09.2012] R&D Projects: GA ČR GAP205/11/2070 Grant - others:Program of the Institute of Fluid Science, Tohoku University, Sendai, Japan (JP) J13032; GA MŠk(CZ) LM2010005 Institutional support: RVO:61389021 Keywords : hybrid-stabilized electric arc * partial characteristics * mass flow rate * Large-eddy simulation * the Smagorinsky sub-grid scale model Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.495, year: 2013 http://www.ifs.tohoku.ac.jp/gcoe/ICFD/ICFD2012/index.html

  5. Waste stabilization/solidification of an electric arc furnace dust using fly ash-based geopolymers

    Energy Technology Data Exchange (ETDEWEB)

    C. Fernandez Pereira; Y. Luna; X. Querol; D. Antenucci; J. Vale [University of Seville, Seville (Spain). School of Industrial Engineering

    2009-07-15

    The stabilization/solidification (S/S) of a carbon steel electric arc furnace (EAF) dust containing hazardous metals such as Pb, Cd, Cr or Zn using geopolymerization technology is described in this paper. Different reagents such as sodium hydroxide, potassium hydroxide, sodium silicate, potassium silicate, kaolinite, metakaolinite and blast furnace slag have been used. Mixtures of EAF waste with these geopolymeric materials and class F fly ash have been processed for studying the potential of geopolymers as waste immobilizing agents. Compressive strength tests and leaching tests for determining the efficiency of heavy metal immobilisation have been carried out. Comparison of fly ash-based geopolymer systems with classic Portland cement stabilization methods has also been accomplished. Compressive strength values far better than those achieved by hydraulic S/S methods were easily obtained by geopolymer solids at 28 days. Regarding leachability, the geopolymer S/S solids also manifested in general a better behaviour, showing very promising results. 40 refs., 1 fig., 9 tabs.

  6. Method and Mechanisms of Soil Stabilization Using Electric Arc Furnace Dust

    Science.gov (United States)

    Al-Amoudi, Omar S. Baghabra; Al-Homidy, Abdullah A.; Maslehuddin, Mohammed; Saleh, Tawfik A.

    2017-04-01

    This paper reports the method and mechanism for improving the strength of marl and desert sand utilizing electric arc furnace dust (EAFD), an industrial by-product, in lieu of cement or lime. EAFD was used in conjunction with a small quantity (2%) of cement. The mechanical properties and durability characteristics of marl and sand mixed with 2% cement plus 5-, 10-, 20- or 30%-EAFD, by weight of the soil, were evaluated. The soil-cement-EAFD mixtures were used to determine their unconfined compressive strength (UCS), soaked California Bearing Ratio (CBR) and durability. The risk of leaching of toxic heavy metals, such as lead and cadmium, from the stabilized soils to the groundwater was also investigated. The mechanisms of stabilization of the selected soils due to the use of EAFD along with a small quantity of cement are also elucidated. The usage of 20 to 30% EAFD with 2% cement was noted to considerably improve the mechanical properties and durability of both marl and sand.

  7. Steel foundry electric arc furnace dust management: stabilization by using lime and Portland cement.

    Science.gov (United States)

    Salihoglu, Guray; Pinarli, Vedat

    2008-05-30

    The purpose of this study was to determine an appropriate treatment for steel foundry electric arc furnace dust (EAFD) prior to permanent disposal. Lime and Portland cement (PC)-based stabilization was applied to treat the EAFD that contains lead and zinc above the landfilling limits, and is listed by USEPA as hazardous waste designation K061 and by EU as 10 02 07. Three types of paste samples were prepared with EAFD content varying between 0 and 90%. The first type contained the EAFD and Portland cement, the second contained the EAFD, Portland cement, and lime, and the third contained the EAFD and lime. All the samples were subjected to toxicity characteristics leaching procedure (TCLP) after an air-curing period of 28 days. pH changes were monitored and acid neutralization capacity of the samples were examined. Treatment effectiveness was evaluated in terms of reducing the heavy metal leachability to the levels below the USEPA landfilling criteria. An optimum composition for the EAFD stabilization was formulated as 30% EAFD +35% lime +35% Portland cement to achieve the landfilling criteria. The pH interval, where the solubility of the heavy metals in the EAFD was minimized, was found to be between 8.2 and 9.4.

  8. Cataphoresis in electric arcs

    Science.gov (United States)

    Murphy, A. B.

    1998-12-01

    A two-dimensional numerical model is used to investigate cataphoresis (demixing driven by electrical fields) in free-burning arcs in mixtures of argon with helium, hydrogen, nitrogen and oxygen at atmospheric pressure. The method of inclusion of electrical field effects in the combined diffusion coefficient treatment of diffusion and demixing is presented. Cataphoresis is found to lead to large increases in helium concentration near the anode in argon-helium arcs and smaller decreases in hydrogen concentration near the axis in argon-hydrogen arcs. There is no significant effect in argon-nitrogen and argon-oxygen arcs. The effects of cataphoresis on other arc properties are generally small and are significant only in argon-helium arcs.

  9. Electric arc hydrogen heaters

    International Nuclear Information System (INIS)

    Zasypin, I.M.

    2000-01-01

    The experimental data on the electric arc burning in hydrogen are presented. Empirical and semiempirical dependences for calculating the arc characteristics are derived. An engineering method of calculating plasma torches for hydrogen heating is proposed. A model of interaction of a hydrogen arc with a gas flow is outlined. The characteristics of plasma torches for heating hydrogen and hydrogen-bearing gases are described. (author)

  10. Electric contact arcing

    International Nuclear Information System (INIS)

    Cuthrell, R.E.

    1976-01-01

    Electrical contacts must function properly in many types of components used in nuclear weapon systems. Design, application, and testing of these components require detailed knowledge of chemical and physical phenomena associated with stockpile storage, stockpile testing, and operation. In the past, investigation of these phenomena has led to significant discoveries on the effects of surface contaminants, friction and wear, and the mechanics of closure on contact performance. A recent investigation of contact arcing phenomena which revealed that, preceding contact closure, arcs may occur at voltages lower than had been previously known is described. This discovery is important, since arcing may damage contacts, and repetitive testing of contacts performed as part of a quality assurance program might produce cumulative damage that would yield misleading life-test data and could prevent proper operation of the contacts at some time in the future. This damage can be avoided by determining the conditions under which arcing occurs, and ensuring that these conditions are avoided in contact testing

  11. Investigation of possibility for stabilization and valorization of electric ARC furnace dust and glass from electronic waste

    Directory of Open Access Journals (Sweden)

    Ranitović M.

    2014-01-01

    Full Text Available This paper presents investigation of possibility for electric arc furnace dust (EAFD and electronic waste (e-waste valorization trough stabilization process, in order to achieve concurrent management of these two serious ecological problems. EAFD is an ineviTab. waste material coming from the electric arc furnace steel production process, classified as a hazardous waste. Furthermore, it is well known that residual materials generated in the ewaste recycling process, like LCD (Liquid crystal displays waste glass, are not suiTab. for landfill or incineration. In this study, these two materials were used for investigation of possibility for their valorization in ceramic industry. Thus, an innovative synergy of waste streams from metallurgical and e-waste recycling industry is presented. Investigation included a complex characterization of raw materials and their mixtures, using chemical methods, optical microscopy, scanning electron microscopy, as well as methods for determining the physical and mechanical properties. Based on these results, it was found that material suiTab. for use in ceramics industry as a partial substituent of quartzite and fluxing components can be produced. Besides solving the environmental problem related to EAFD and LCD disposal, by replacement of raw materials certain economic effects can be achieved. [Projekat Ministarstva nauke Republike Srbije, br. 34033

  12. Stabilization and solidification of electric arc furnace dust originating from steel industry by using low grade MgO

    Directory of Open Access Journals (Sweden)

    Bayraktar Ahmet Can

    2015-12-01

    Full Text Available In this study, solidification/stabilization (S/S of electric arc furnace dust (EAFD which is generated during the production of steel from scrap metals and classified as hazardous waste were investigated by using different ratios of cement and low grade MgO (LG MgO as binding agents. Type I PC 42.5 R portland cement and LG MgO which contains 70–80% MgO were used. S/S blocks that contain different ratios of binding agents which have 1/0.5 – 1/1 – 1/2 – 1/3 – 1/4 – 1/5 cement/LG MgO ratio and S/S blocks which contain only cement and no LG MgO agents were prepared. These blocks, which contain 3 different waste ratios according to weight, 20%, 30% and 40% respectively, were produced and exposed to 28-day water purification. At the end of the purification process, S/S blocks were extracted using TCLP (Toxicity Characteristic Leaching Procedure tests in order to determine the leaching behavior of Zn, Pb, and Cd in S/S blocks. By the end of this study, it was concluded that the recovery of EAFD is possible and applicable by immobilization. The findings of the study concluded that environmental performances or structural properties of blocks contain 30% waste by weight are suitable. This method is a proper one for recovering and treatment of EAFD with mixture of cement and LG MgO.

  13. Electric arc welding gun

    Science.gov (United States)

    Luttrell, Edward; Turner, Paul W.

    1978-01-01

    This invention relates to improved apparatus for arc welding an interior joint formed by intersecting tubular members. As an example, the invention is well suited for applications where many similar small-diameter vertical lines are to be welded to a long horizontal header. The improved apparatus includes an arc welding gun having a specially designed welding head which is not only very compact but also produces welds that are essentially free from rolled-over solidified metal. The welding head consists of the upper end of the barrel and a reversely extending electrode holder, or tip, which defines an acute angle with the barrel. As used in the above-mentioned example, the gun is positioned to extend upwardly through the vertical member and the joint to be welded, with its welding head disposed within the horizontal header. Depending on the design of the welding head, the barrel then is either rotated or revolved about the axis of the vertical member to cause the electrode to track the joint.

  14. Surface erosion by electrical arcs

    International Nuclear Information System (INIS)

    Behrisch, R.

    1984-01-01

    The authors discuss traces of cathode spots from electrical arcs observed on the vessel walls of high temperature plasma experiments. They originate from short metal plasma discharges which can be ignited at the walls due to the Langmuir sheath potential in front of the walls and thus the hydrogen plasma acts as the anode. The arcs may also be caused by electrical potentials which are created by gradients in the plasma, by plasma motion or during disruptive plasma phases. The material eroded from the walls at the cathode spots contributes to impurity introduction into the hydrogen plasma. Further arcing is a critical issue in high intensity ion sources and in RF transmitters and antennas for plasma heating

  15. Rotating Drive for Electrical-Arc Machining

    Science.gov (United States)

    Fransen, C. D.

    1986-01-01

    Rotating drive improves quality of holes made by electrical-arc machining. Mechanism (Uni-tek, rotary head, or equivalent) attached to electrical-arc system. Drive rotates electrode as though it were mechanical drill, while an arc disintegrates metal in workpiece, thereby creating hole. Rotating electrode method often used in electric-discharge machining. NASA innovation is application of technique to electrical-arc machining.

  16. Preliminary Study of Mixing of Plasma Species in a Hybrid-Stabilized Argon-Water Electric Arc

    Czech Academy of Sciences Publication Activity Database

    Jeništa, Jiří; Takana, H.; Uehara, S.; Nishiyama, H.; Murphy, A.B.; Bartlová, M.; Aubrecht, V.

    2015-01-01

    Roč. 2, č. 3 (2015), s. 316-319 ISSN 2336-2626. [Symposium on Physics of Switching Arc/21./. Nové Město na Moravě, 07.09.2015-11.09.2015] R&D Projects: GA ČR(CZ) GA15-19444S Institutional support: RVO:61389021 Keywords : arc discharge * combined diffusion coefficients * inhomogeneous mixing * mass fraction Subject RIV: BL - Plasma and Gas Discharge Physics https://www.vutbr.cz/www_base/vutdisk.php?i=36809a9aa

  17. Performance of water and hybrid stabilized electric arcs: the impact of dependence of radiation losses and plasma density on pressure

    Czech Academy of Sciences Publication Activity Database

    Jeništa, Jiří; Bartlová, M.; Aubrecht, V.

    2006-01-01

    Roč. 56, suppl.B (2006), B1224-B1230 ISSN 0011-4626. [Symposium on Plasma Physics and Technology/22th./. Praha, 26.6.2006-29.6.2006] R&D Projects: GA ČR GA202/05/0669 Institutional research plan: CEZ:AV0Z20430508 Keywords : arc * torch * hybrid (water) discharge * divergence of radiation flux * radiation Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.568, year: 2006

  18. GUI for studying the parameters influence of the electric arc model for a three-phase electric arc furnace

    Science.gov (United States)

    Ghiormez, L.; Prostean, O.; Panoiu, M.; Panoiu, C.

    2017-01-01

    This paper presents an analysis regarding the modeling of the behavior for a three-phase electric arc furnace installation. Therefore, a block diagram is implemented in Simulink that represents the modeling of the entire electric arc furnace installation. This block diagram contains also the modeling of the electric arc which is the element that makes the electric arc furnace behaving as a nonlinear load. The values for the model parameters of the electric arc furnace installation are like the ones from the real installation taken into consideration. Other model parameters are the electric arc model ones. In order to study the influence of the parameters of the electric arc models, it is developed a Matlab program that contains the graphical user interfaces. These interfaces make connection with the models of the electric arc implemented in Simulink. The interfaces allow the user to modify parameters for each of the electric arc model. Current and voltage of the electric arc are the variables taken into account to study the influence of the parameters on the electric arc models. Waveforms for voltage and current of the electric arc are illustrated when a parameter of the model is modified in order to analyze the importance of this parameter on the electric arc model. Also, for each of the models is presented the voltage-current characteristic of the electric arc because this characteristic gives information about the behavior of the electric arc furnace installation.

  19. Electric arc, water jet cutting of metals

    International Nuclear Information System (INIS)

    Bruening, D.

    1991-01-01

    For thermal dismantling and cutting of metallic components, as electric arc, water jet cutting method was developed that can be used for underwater cutting work up to a depth of 20 m. Short-circuiting of a continuously fed electrode wire in contact with the metal generates an electric arc which induces partial melting of the metal, and the water jet surrounding the wire rinses away the molten material, thus making a continuous kerf in the material. The method was also tested and modified to allow larger area, surface cutting and removal of metallic surface coatings. This is achieved by melting parts of the surface with the electric arc and subsequent rinsing by the water jet. The cutting and melting depth for surface removal can be accurately controlled by the operating parameters chosen. (orig./DG) [de

  20. Electrical Safety and Arc Flash Protections

    Energy Technology Data Exchange (ETDEWEB)

    R. Camp

    2008-03-04

    Over the past four years, the Electrical Safety Program at PPPL has evolved in addressing changing regulatory requirements and lessons learned from accident events, particularly in regards to arc flash hazards and implementing NFPA 70E requirements. This presentation will discuss PPPL's approaches to the areas of electrical hazards evaluation, both shock and arc flash; engineered solutions for hazards mitigation such as remote racking of medium voltage breakers, operational changes for hazards avoidance, targeted personnel training and hazard appropriate personal protective equipment. Practical solutions for nominal voltage identification and zero voltage checks for lockout/tagout will also be covered. Finally, we will review the value of a comprehensive electrical drawing program, employee attitudes expressed as a personal safety work ethic, integrated safety management, and sustained management support for continuous safety improvement.

  1. Electrical Safety and Arc Flash Protections

    International Nuclear Information System (INIS)

    Camp, R.

    2008-01-01

    Over the past four years, the Electrical Safety Program at PPPL has evolved in addressing changing regulatory requirements and lessons learned from accident events, particularly in regards to arc flash hazards and implementing NFPA 70E requirements. This presentation will discuss PPPL's approaches to the areas of electrical hazards evaluation, both shock and arc flash; engineered solutions for hazards mitigation such as remote racking of medium voltage breakers, operational changes for hazards avoidance, targeted personnel training and hazard appropriate personal protective equipment. Practical solutions for nominal voltage identification and zero voltage checks for lockout/tagout will also be covered. Finally, we will review the value of a comprehensive electrical drawing program, employee attitudes expressed as a personal safety work ethic, integrated safety management, and sustained management support for continuous safety improvement.

  2. Auroral arc classification scheme based on the observed arc-associated electric field pattern

    International Nuclear Information System (INIS)

    Marklund, G.

    1983-06-01

    Radar and rocket electric field observations of auroral arcs have earlier been used to identify essentially four different arc types, namely anticorrelation and correlation arcs (with, respectively, decreased and increased arc-assocaited field) and asymmetric and reversal arcs. In this paper rocket double probe and supplementary observations from the literature, obtained under various geophysical conditions, are used to organize the different arc types on a physical rather than morphological basis. This classification is based on the relative influence on the arc electric field pattern from the two current continuity mechanisms, polarisation electric fields and Birkeland currents. In this context the tangential electric field plays an essential role and it is thus important that it can be obtained with both high accuracy and resolution. In situ observations by sounding rockets are shown to be better suited for this specific task than monostatic radar observations. Depending on the dominating mechanism, estimated quantitatively for a number of arc-crossings, the different arc types have been grouped into the following main categories: Polarisation arcs, Birkeland current arcs and combination arcs. Finally the high altitude potential distributions corresponding to some of the different arc types are presented. (author)

  3. Displacement of an electric arc by a stationary transverse magnetic field to different pressures of the ionized gas

    International Nuclear Information System (INIS)

    Ramos, J.

    1987-01-01

    The displacement of a wall-stabilized electric arc by a stationary transverse magnetic field is measured to different pressures of the ionized gas. The increase of the pressure makes the heat transfer function and the mass flow velocity in the arc column to raise, and it makes the arc displacement to decrease. (author)

  4. Stability evaluation of short-circuiting gas metal arc welding based on ensemble empirical mode decomposition

    Science.gov (United States)

    Huang, Yong; Wang, Kehong; Zhou, Zhilan; Zhou, Xiaoxiao; Fang, Jimi

    2017-03-01

    The arc of gas metal arc welding (GMAW) contains abundant information about its stability and droplet transition, which can be effectively characterized by extracting the arc electrical signals. In this study, ensemble empirical mode decomposition (EEMD) was used to evaluate the stability of electrical current signals. The welding electrical signals were first decomposed by EEMD, and then transformed to a Hilbert-Huang spectrum and a marginal spectrum. The marginal spectrum is an approximate distribution of amplitude with frequency of signals, and can be described by a marginal index. Analysis of various welding process parameters showed that the marginal index of current signals increased when the welding process was more stable, and vice versa. Thus EEMD combined with the marginal index can effectively uncover the stability and droplet transition of GMAW.

  5. Stability of alternating current gliding arcs

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Salewski, Mirko; Leipold, Frank

    2014-01-01

    on Ohm’s law indicates that the critical length of alternating current (AC) gliding arc discharge columns can be larger than that of a corresponding direct current (DC) gliding arc. This finding is supported by previously published images of AC and DC gliding arcs. Furthermore, the analysis shows...... that the critical length can be increased by increasing the AC frequency, decreasing the serial resistance and lowering the gas flow rate. The predicted dependence of gas flow rate on the arc length is experimentally demonstrated. The gap width is varied to study an optimal electrode design, since the extended non...

  6. Analysis of arc emission spectra of stainless steel electric arc furnace slag affected by fluctuating arc voltage.

    Science.gov (United States)

    Aula, Matti; Mäkinen, Ari; Fabritius, Timo

    2014-01-01

    Control of chromium oxidation in the electric arc furnace (EAF) is a significant problem in stainless steel production due to variations of the chemical compositions in the EAF charge. One potential method to control chromium oxidation is to analyze the emission spectrum of the electric arc in order to find indicators of rising chromium content in slag. The purpose of this study was to determine if slag composition can be gained by utilizing electric arc emission spectra in the laboratory environment, despite electric arc voltage fluctuations and varying slag composition. The purpose of inducing voltage fluctuation was to simulate changes in the industrial EAF process. The slag samples were obtained from Outokumpu Stainless Oy Tornio Works, and three different arc currents were used. The correlation analysis showed that the emission spectra offer numerous peak ratios with high correlations to the X-ray fluorescence-measured slag CrO(x)/FeO(x) and MnO/SiO2 ratios. These ratios are useful in determining if the reduction agents have been depleted in the EAF. The results suggest that analysis of laboratory-scale electric arc emission spectra is suitable for indicating the high CrO(x) or MnO content of the slag despite the arc fluctuations. Reliable analysis of other slag components was not successful.

  7. Electric fuses operation, a review: 2. Arcing period

    International Nuclear Information System (INIS)

    Bussière, W

    2012-01-01

    In the electric fuse operation the arcing period follows immediately the pre-arcing period depicted in Part 1 (Part 1. Pre-arcing period). The transition between these two operation steps is not fully understood at this time. To simplify the beginning of the arcing period can be identified with the electric arc ignition i.e. with the electrodes voltage drop. The consecutive plasma is of metallic type at the beginning of the arcing period and of metallic plus silica type with varying mixture up to the end of the arcing period. The energy brought by the fault current is withdrawn by means of the interaction between the electric arc and the arc quenching material (usually silica sand) whose morphometric properties influence the properties of the plasma column: composition, thermodynamic properties and transport coefficients of the plasma column depend on the porosity (and other morphometric properties) of the filler. The fuse element erosion also known as burn-back is responsible for the lengthening of the plasma column and the variations of the electric field. The whole of these processes is depicted by means of experimental results or modellings when possible.

  8. Power quality analysis of DC arc furnace operation using the Bowman model for electric arc

    Science.gov (United States)

    Gherman, P. L.

    2018-01-01

    This work is about a relatively new domain. The DC electric arc is superior to the AC electric arc and it’s not used in Romania. This is why we analyzed the work functions of these furnaces by simulation and model checking of the simulation results.The conclusions are favorable, to be carried is to develop a real-time control system of steel elaboration process.

  9. Thermal Plasma Generators with Water Stabilized Arc

    Czech Academy of Sciences Publication Activity Database

    Hrabovský, Milan

    2009-01-01

    Roč. 2, č. 1 (2009), s. 99-104 ISSN 1876-5343 R&D Projects: GA ČR GA202/08/1084 Institutional research plan: CEZ:AV0Z20430508 Keywords : Thermal plasma * plasma torch * Gerdien arc Subject RIV: BL - Plasma and Gas Discharge Physics http://www.bentham.org/open/toppj/openaccess2.htm

  10. Enhancing stability of industrial turbines using adjustable partial arc bearings

    Science.gov (United States)

    Chasalevris, Athanasios; Dohnal, Fadi

    2016-09-01

    The paper presents the principal of operation, the simulation and the characteristics of two partial-arc journal bearings of variable geometry and adjustable/controllable stiffness and damping properties. The proposed journals are supposed to consist of a scheme that enables the periodical variation of bearing properties. Recent achievements of suppressing rotor vibrations using plain circular journal bearings of variable geometry motivate the further extension of the principle to bearings of applicable geometry for industrial turbines. The paper describes the application of a partial-arc journal bearing to enhance stability of high speed industrial turbines. The proposed partial-arc bearings with adjustable/controllable properties enhance stability and they introduce stable margins in speeds much higher than the 1st critical.

  11. Resource-saving method of electric arc spraying

    OpenAIRE

    Roianov, Viacheslav O.; Bobikov, Volodymyr I.

    2015-01-01

    On the modern stage of development of resource-saving technologies the basic support is given to the economy of materials consumption without the change of the amount of their use. The special attention is given to the universal methods of renewal of details, and electric arc spraying which has a wide application did not become an exception. The review of the literary data shows that the applied electric arc spraying guns have a large expense of the compressed air. It results in the intensive...

  12. Processes of energy exchange between blasted electric arc and surrounding gas in arc heater channel

    Czech Academy of Sciences Publication Activity Database

    Heinz, J.; Šenk, J.; Hrabovský, Milan

    2002-01-01

    Roč. 52, supplement D (2002), s. 583 ISSN 0011-4626. [Symposium on Plasma Physics and Technology/20th./. Prague, 10.06.2002-13.06.2002] Institutional research plan: CEZ:AV0Z2043910 Keywords : electric arc, energy exchance, heater Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.311, year: 2002

  13. Innovation in electric arc furnaces scientific basis for selection

    CERN Document Server

    Toulouevski, Yuri N

    2013-01-01

    This book equips a reader with knowledge necessary for critical analysis of  innovations in electric arc furnaces and helps to select the most effective ones and for their successful implementation. The book also covers general issues related to history of development, current state and prospects of steelmaking in Electric Arc Furnaces. Therefore, it can be useful for everybody who studies metallurgy, including students of colleges and universities. The modern concepts of mechanisms of Arc Furnace processes are are discussed in the book at the level sufficient to solve practical problems: To help readers lacking knowledge required in the field of heat transfer as well as hydro-gas dynamics, it contains several chapters which provide the required minimum of information in these fields of science. In order to better assess different innovations, the book describes experience of the application of similar innovations in open-hearth furnaces and oxygen converters. Some promising ideas on key issues regarding int...

  14. Inner tubes cutting method by electrical arc saw

    International Nuclear Information System (INIS)

    Thome, P.

    1990-01-01

    The research program deals on the definition of tools used for dismantling steam generator tubes bundle of PWR and on tool used for cutting pipes of great diameter by using the process of cutting by electrical arc saw. The remote tools are used for cutting by the interior pipes of contamined circuits [fr

  15. Suitability of Electric Arc Furnace (Eaf) Slag as Partial Replacement ...

    African Journals Online (AJOL)

    The use of Electric Arc Furnace (EAF) Slag which is a by-product solid waste in Steel Production was investigated for use as a partial replacement for cement in sandcrete blocks. The tests carried out on cement and finely ground slag to determine their compositions and physico-chemical properties as well as the evaluation ...

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

    Science.gov (United States)

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

    2016-05-01

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

  17. Vortex flow in a torus - a method for arc stabilization

    International Nuclear Information System (INIS)

    Polman, R.W.

    1976-08-01

    Experiments on ring vortices inside a torus and experiments on semi-toroidal arcs stabilized by such vortices are described. The studies were performed in two separate devices. One of the toroidal vortex chambers - 'Cogion', with R = 0.45 m and r = 0.10 m - permits the establishment of a gas flow only. In the other device - 'Tovorex', with R = 0.19 m and r = 0.04 m - it is also possible to draw a semi-toroidal arc. The measurements surprisingly show that it is possible to describe the radial distribution of the poloidal flow in terms of a plane turbulent wall jet discharging in an external stream. The velocity profile and the growth of the width of the jet are in accordance with experimental data on this subject. A different behaviour is found for the decay of the maximum velocity. The core of the flow proves to be almost stagnant; the axis of rotation is displaced outwardly with respect to the centre of the cross-section over a distance of 6 mm. In 'Tovorex' information about the rotating flow is obtained without the presence of an arc in the vortex core. The velocity profiles prove to be independent of the pressure (50-400 Torr). For experiments with arcs nitrogen is used. It has been found that the semi-toroidal DC-arc, surrounded by a continuous metal wall can be stabilized by the toroidal vortices in the experimental range30 -1 , 0.6 -1 , depends on the current and on the pressure and is independent of Usub(j) and a. Temperatures of the discharge are estimated at approximately 6000 K. The velocity profiles in both vortex chambers are obtained with a hot-wire anemometer operated at constant resistance

  18. Internal Arc: People safety in the electrical wiring

    International Nuclear Information System (INIS)

    Inchausti, J. M.

    2009-01-01

    The aim of this article is to describe the internal arc phenomenon, an extremely fast, almost explosive and unattended process of transformation form an initial electric power to the generation of a pressure and heat wave inside the medium its produced its consequences for safety, current methods of limiting them and current regulations in general for equipment used in medium-voltage electrical distribution networks. Taking into account that this type of equipment is found thought the distribution network in both public buildings and unrestricted access areas, safety (of operators and the general public) must be taken into account in the design of equipment and installations to minimize the risk of internal arcs occurring. This is the gist of, for example, ITC 16 of the Spanish Regulation on Power Plants and transformer substations. In addition to the construction aspects specific to each device in which the manufacturer has to takes steps to minimize the risks of an internal arcs occurring. This is the gist of, for example, ITC 16 of the Spanish Regulation on Power Plants and transformer substations. In addition to the construction aspects specific to each device in which an internal arc occurring, it is understood to be vitally important that users, installers and designers of Medium Voltage installations are familiar with the installation conditions stated by the manufacturer and thus avoid risks. (Author) 14 refs

  19. Elements of the electric arc furnace's environmental management

    Science.gov (United States)

    Ioana, Adrian; Semenescu, Augustin; Costoiu, Mihnea; Marcu, Dragoş

    2017-12-01

    The paper presents a theoretical and experimental analysis of the polluting generating mechanisms for steel making in the Electric Arc Furnaces (EAF). The scheme for the environment's polluting system through the EAF is designed and presented in this paper. The ecological experimenting consisted of determining by specialized measures of the dust percentage in the evacuated gases from the EAF and of thereof gas pollutants. From the point of view of reducing the impact on the environment, the main problem of the electric arc furnace (EAF) is the optimization of the powder collecting from the process gases, both from the furnace and from the work-area. The paper deals with the best dependence between the aggregate's constructive, functional and technological factors, which are necessary for the furnace's ecologization and for its energetically-technologically performances increasing.

  20. Pragmatic analysis of the electric submerged arc furnace continuum

    Science.gov (United States)

    Karalis, K.; Karkalos, N.; Antipas, G. S. E.; Xenidis, A.

    2017-09-01

    A transient mathematical model was developed for the description of fluid flow, heat transfer and electromagnetic phenomena involved in the production of ferronickel in electric arc furnaces. The key operating variables considered were the thermal and electrical conductivity of the slag and the shape, immersion depth and applied electric potential of the electrodes. It was established that the principal stimuli of the velocities in the slag bath were the electric potential and immersion depth of the electrodes and the thermal and electrical conductivities of the slag. Additionally, it was determined that, under the set of operating conditions examined, the maximum slag temperature ranged between 1756 and 1825 K, which is in accordance with industrial measurements. Moreover, it was affirmed that contributions to slag stirring due to Lorentz forces and momentum forces due to the release of carbon monoxide bubbles from the electrode surface were negligible.

  1. A novel estimation of electrical and cooling losses in electric arc furnaces

    International Nuclear Information System (INIS)

    Trejo, Eder; Martell, Fernando; Micheloud, Osvaldo; Teng, Lidong; Llamas, Armando; Montesinos-Castellanos, Alejandro

    2012-01-01

    A method to calculate electrical losses and a heat transfer model of a conventional Electric Arc Furnace (EAF) are presented. The application of a novel power theory for the EAF was used to compute electrical losses and it was compared with conventional power calculations. The electrical losses and electrical variables were used as input parameters to the proposed heat transfer model. Chemical energy sources were included as energy inputs to estimate the overall heat transferred including the heat losses in the cooling system. In the heat transfer model the furnace was divided in 11 inner surfaces and the radiation view factors between them were estimated by a commercial finite element software. Variations of the view factors for different arc coverage were evaluated. Different scenarios for cooling panels losses, with respect to arc coverage and thickness of slag layers adhered to cooling system panels, were analyzed. The approach presented in this work allows calculation of energy balances in electrical arc furnaces with low computational resources. Finally, the contribution of this research work is to define a framework for further research oriented to improve both the electrical and thermal energy efficiencies to increase productivity and reduce energy consumption in steel plants. -- Highlights: ► Radiation view factors for the electric arc furnace are estimated. ► Potential reduction in cooling losses is estimated to be 60 kWh/ton. ► Electrical losses are calculated based in the randomness power theory. ► The new approach yields an increase of 10% in the electrical losses. ► An analytic model is used to estimate the radiation mechanism.

  2. Effects of lorentz force on flow fields of free burning arc and wall stabilized non-transferred arc

    International Nuclear Information System (INIS)

    Peng Yi; Huang Heji; Pan Wenxia

    2013-01-01

    The flow fields of two typical DC plasma arcs, namely the transferred free burning arc and the non-transferred arc were simulated by solving hydrodynamic equations and electromagnetic equations. The effects of the Lorentz force on the characteristics of the flow fields of these two typical DC plasma arcs were estimated. Results show that in the case of the free burning arc, the Lorentz force due to the current self-induced magnetic field has significant impact on the flow fields, as the self-induced magnetic compression is the main arc constraint mechanism. However, in the case of the non-transferred arc generated in a torch with long and narrow inter-electrode inserts and an abruptly expanded anode, the Lorentz force has limited impact on the flow fields of the plasma especially at the downstream of the inter-electrode inserts, compared with the strong wall constraints and relatively high aerodynamic force. This is because the ratio of the electromagnetic force to the aerodynamic force is only about 0.01 in this region. When the main consideration is outlet parameters of the wall stabilized non-transferred DC arc plasma generator, in order to improve the efficiency of the numerical simulation program, the Lorentz force could be neglected in the non-transferred arc in some cases. (authors)

  3. Investigation of Voltage Unbalance Problems In Electric Arc Furnace Operation Model

    Directory of Open Access Journals (Sweden)

    Yacine DJEGHADER

    2013-06-01

    Full Text Available In modern steel industry, Electric Arc Furnaces are widely used for iron and scarp melting. The operation of electric arc furnace causes many power quality problems such as harmonics, unbalanced voltage and flicker. The factors that affect Electric arc furnace operation are the melting or refining materials, melting stage, electrodes position (arc length, electrode arm control and short circuit power of the feeder, so, arc voltages, current and power are defined as a nonlinear function of arc length. This study focuses on investigation of unbalanced voltage due to Electrics Arc Furnace operation mode. The simulation results show the major problem of unbalanced voltage affecting secondary of furnace transformer is caused by the different continues movement of electrodes.

  4. Glass-ceramic materials from electric arc furnace dust

    International Nuclear Information System (INIS)

    Kavouras, P.; Kehagias, T.; Tsilika, I.; Kaimakamis, G.; Chrissafis, K.; Kokkou, S.; Papadopoulos, D.; Karakostas, Th.

    2007-01-01

    Electric arc furnace dust (EAFD) was vitrified with SiO 2 , Na 2 CO 3 and CaCO 3 powders in an electric furnace at ambient atmosphere. Vitreous products were transformed into glass-ceramic materials by two-stage heat treatment, at temperatures determined by differential thermal analysis. Both vitreous and glass-ceramic materials were chemically stable. Wollastonite (CaSiO 3 ) was separated from the parent matrix as the dominant crystalline phase, verified by X-ray diffraction analysis and energy dispersive spectrometry. Transmission electron microscopy revealed that wollastonite crystallizes mainly in its monoclinic form. Knoop microhardness was measured with the static indentation test method in all initial vitreous products and the microhardness values were in the region of 5.0-5.5 GPa. Devitrification resulted in glass-ceramic materials with microhardness values strongly dependent on the morphology and orientation of the separated crystal phase

  5. Methods of steel manufacturing - The electric arc furnace

    Science.gov (United States)

    Dragna, E. C.; Ioana, A.; Constantin, N.

    2018-01-01

    Initially, the carbon content was reduced by mixing “the iron” with metallic ingots in ceramic crucibles/melting pots, with external heat input. As time went by the puddling procedure was developed, a procedure which also assumes a mixture with oxidized iron ore. In 1856 Bessemer invented the convertor, thus demonstrating that steel can be obtained following the transition of an air stream through the liquid pig iron. The invention of Thomas, a slightly modified basic-lined converter, fostered the desulphurization of the steel and the removal of the phosphate from it. During the same period, in 1865, in Sireuil, the Frenchman Martin applies Siemens’ heat regeneration invention and brings into service the furnace with a charge composed of iron pig, scrap iron and iron ore, that produces a high quality steel [1]. An act worthy of being highlighted within the scope of steelmaking is the start-up of the converter with oxygen injection at the upper side, as there are converters that can produce 400 tons of steel in approximately 50 minutes. Currently, the share of the steel produced in electric arc furnaces with a charge composed of scrap iron has increased. Due to this aspect, the electric arc furnace was able to impose itself on the market.

  6. Methods of selective protection against electric arcs; Metodos de protecao seletiva contra arcos eletricos

    Energy Technology Data Exchange (ETDEWEB)

    Kumpulainen, Lauri; Dahl, Samuel [Vamp Ltd. (Finland)

    2010-12-15

    The faults with electric arcs can cause serious accidents and endanger the safety of people and equipment, which necessitates effective methods to reduce the impact of these incidents. This article discusses ways to mitigate electric arcs and encourages the use of technology based on light detection, with its benefits and practical applications.

  7. Mathematical Model and the Simulation of Electrical Arc Welding as Moving Source in Protector Gas Welding

    Directory of Open Access Journals (Sweden)

    Lenuta Suciu

    2006-10-01

    Full Text Available The works presents the mathematical model of electrical arc welding, simulation of the electrical arc as a moving source with help programs software Ansys, passing through three stage of simulation: pre- processing, processing (solution and post-processing.

  8. Modeling of Radiative Heat Transfer in an Electric Arc Furnace

    Science.gov (United States)

    Opitz, Florian; Treffinger, Peter; Wöllenstein, Jürgen

    2017-12-01

    Radiation is an important means of heat transfer inside an electric arc furnace (EAF). To gain insight into the complex processes of heat transfer inside the EAF vessel, not only radiation from the surfaces but also emission and absorption of the gas phase and the dust cloud need to be considered. Furthermore, the radiative heat exchange depends on the geometrical configuration which is continuously changing throughout the process. The present paper introduces a system model of the EAF which takes into account the radiative heat transfer between the surfaces and the participating medium. This is attained by the development of a simplified geometrical model, the use of a weighted-sum-of-gray-gases model, and a simplified consideration of dust radiation. The simulation results were compared with the data of real EAF plants available in literature.

  9. Compacting of fly dusts from cupola and electric arc furnace

    Directory of Open Access Journals (Sweden)

    D. Baricová

    2012-01-01

    Full Text Available Recycling and utilization of dust waste is important not only from the point of view of its usage as an alternative source of raw materials, but regarding the environmental problems also. Dust emissions arise from thermal and chemical or physical processes and mechanical actions. Two kinds of fl y dusts from cupola furnaces (hot and cold blast cupola furnace and fl y dust from electric arc furnace were used by experiments. They were pelletized only with addition of water and briquetted with diff erent addition of water glass, bentonite and cement. Quality of briquettes was tested by compression – strength test and by break down test in green state, after drying and afterstoring (1 month.

  10. A Novel Arc Fault Detector for Early Detection of Electrical Fires.

    Science.gov (United States)

    Yang, Kai; Zhang, Rencheng; Yang, Jianhong; Liu, Canhua; Chen, Shouhong; Zhang, Fujiang

    2016-04-09

    Arc faults can produce very high temperatures and can easily ignite combustible materials; thus, they represent one of the most important causes of electrical fires. The application of arc fault detection, as an emerging early fire detection technology, is required by the National Electrical Code to reduce the occurrence of electrical fires. However, the concealment, randomness and diversity of arc faults make them difficult to detect. To improve the accuracy of arc fault detection, a novel arc fault detector (AFD) is developed in this study. First, an experimental arc fault platform is built to study electrical fires. A high-frequency transducer and a current transducer are used to measure typical load signals of arc faults and normal states. After the common features of these signals are studied, high-frequency energy and current variations are extracted as an input eigenvector for use by an arc fault detection algorithm. Then, the detection algorithm based on a weighted least squares support vector machine is designed and successfully applied in a microprocessor. Finally, an AFD is developed. The test results show that the AFD can detect arc faults in a timely manner and interrupt the circuit power supply before electrical fires can occur. The AFD is not influenced by cross talk or transient processes, and the detection accuracy is very high. Hence, the AFD can be installed in low-voltage circuits to monitor circuit states in real-time to facilitate the early detection of electrical fires.

  11. A Novel Arc Fault Detector for Early Detection of Electrical Fires

    Science.gov (United States)

    Yang, Kai; Zhang, Rencheng; Yang, Jianhong; Liu, Canhua; Chen, Shouhong; Zhang, Fujiang

    2016-01-01

    Arc faults can produce very high temperatures and can easily ignite combustible materials; thus, they represent one of the most important causes of electrical fires. The application of arc fault detection, as an emerging early fire detection technology, is required by the National Electrical Code to reduce the occurrence of electrical fires. However, the concealment, randomness and diversity of arc faults make them difficult to detect. To improve the accuracy of arc fault detection, a novel arc fault detector (AFD) is developed in this study. First, an experimental arc fault platform is built to study electrical fires. A high-frequency transducer and a current transducer are used to measure typical load signals of arc faults and normal states. After the common features of these signals are studied, high-frequency energy and current variations are extracted as an input eigenvector for use by an arc fault detection algorithm. Then, the detection algorithm based on a weighted least squares support vector machine is designed and successfully applied in a microprocessor. Finally, an AFD is developed. The test results show that the AFD can detect arc faults in a timely manner and interrupt the circuit power supply before electrical fires can occur. The AFD is not influenced by cross talk or transient processes, and the detection accuracy is very high. Hence, the AFD can be installed in low-voltage circuits to monitor circuit states in real-time to facilitate the early detection of electrical fires. PMID:27070618

  12. Direct electrical arc ignition of hybrid rocket motors

    Science.gov (United States)

    Judson, Michael I., Jr.

    Hybrid rockets motors provide distinct safety advantages when compared to traditional liquid or solid propellant systems, due to the inherent stability and relative inertness of the propellants prior to established combustion. As a result of this inherent propellant stability, hybrid motors have historically proven difficult to ignite. State of the art hybrid igniter designs continue to require solid or liquid reactants distinct from the main propellants. These ignition methods however, reintroduce to the hybrid propulsion system the safety and complexity disadvantages associated with traditional liquid or solid propellants. The results of this study demonstrate the feasibility of a novel direct electrostatic arc ignition method for hybrid motors. A series of small prototype stand-alone thrusters demonstrating this technology were successfully designed and tested using Acrylonitrile Butadiene Styrene (ABS) plastic and Gaseous Oxygen (GOX) as propellants. Measurements of input voltage and current demonstrated that arc-ignition will occur using as little as 10 watts peak power and less than 5 joules total energy. The motor developed for the stand-alone small thruster was adapted as a gas generator to ignite a medium-scale hybrid rocket motor using nitrous oxide /and HTPB as propellants. Multiple consecutive ignitions were performed. A large data set as well as a collection of development `lessons learned' were compiled to guide future development and research. Since the completion of this original groundwork research, the concept has been developed into a reliable, operational igniter system for a 75mm hybrid motor using both gaseous oxygen and liquid nitrous oxide as oxidizers. A development map of the direct spark ignition concept is presented showing the flow of key lessons learned between this original work and later follow on development.

  13. Equilibrium stability and sub-millisecond refolding of a designed single-chain Arc repressor.

    Science.gov (United States)

    Robinson, C R; Sauer, R T

    1996-11-05

    Arc-L1-Arc is a single-chain variant of bacteriophage P22 Arc repressor in which a 15 residue linker joins the C-terminus of one subunit to the N-terminus of an otherwise identical subunit. Spectroscopic probes indicate that the native and denatured state of the single-chain protein are similar to those of the unlinked Arc dimer. In equilibrium experiments, Arc-L1-Arc denatures in a reaction without populated intermediate states as judged by the fits of the denaturation isotherms to a two-state model and by the coincidence of denaturation curves monitored by fluorescence and circular dichroism. Comparison of the equilibrium stabilities of Arc-L1-Arc and unlinked Arc gives an effective concentration of subunits in the denatured single-chain variant of 2.7 (+/- 0.7) mM. The kinetic refolding and unfolding reactions of Arc-L1-Arc also appear to proceed without populated intermediates. The rate constant for Arc-L1-Arc unfolding is about 2-fold faster than that of unlinked Arc, indicating that the linker mediates no significant contacts in the native structure that need to be broken to allow unfolding. As expected, the major effect of the linker occurs during the refolding reaction, where the effective subunit concentration calculated from the bimolecular and unimolecular refolding rate constants is 4.5 (+/- 1.8) mM. The transition states for the unfolding and refolding reactions of Arc-L1-Arc and wild-type Arc have similar solvent exposures as measured by the urea dependencies of the equilibrium and rate constants. In the absence of urea, the single-chain protein refolds very rapidly (kf approximately 10(4) s-1) in a reaction that is essentially complete in the sub-millisecond time regime.

  14. Quasi-Laminar Flow Characteristics in Hybrid-Stabilized Argon–Water Arc Discharge for Subsonic-Supersonic Regimes

    Czech Academy of Sciences Publication Activity Database

    Jeništa, Jiří; Takana, H.; Nishiyama, H.; Křenek, Petr; Bartlová, M.; Aubrecht, V.

    2014-01-01

    Roč. 42, č. 10 (2014), s. 2632-2633 ISSN 0093-3813 R&D Projects: GA ČR GAP205/11/2070 Institutional support: RVO:61389021 Keywords : Hybrid-stabilized electric arc * large-eddy simulation * partial characteristics * the Smagorinsky subgrid scale model Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.101, year: 2014 http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6876210

  15. Calculation of pressure and temperature in medium-voltage electrical installations due to fault arcs

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X; Gockenbach, E [Institute of Electric Power Systems, Division of High Voltage Engineering, Leibniz University of Hanover, Hanover, 30167 Germany (Germany); Zhang, J [SIEMENS High Voltage Circuit Breaker Ltd Co., Hangzhou, 310018 (China)], E-mail: zhang@si.uni-hannover.de

    2008-05-21

    In order to determine the pressure rise due to arc faults in electrical installations, the portion of energy heating the surrounding gas of fault arcs has to be known. The ratio of the portion of energy to the electric energy, the thermal transfer coefficient, is adopted as the k{sub p} factor. This paper presents a theoretical approach for the determination of the thermal transfer coefficient and the pressure rise in electrical installations. It is based on the fundamental hydro- and thermodynamic conservation equations and the equation of gas state taking into account melting and evaporation of metals as well as chemical reactions with the surrounding gas. In order to consider the dependence of the arc energy on the gas density, the radiative effect of fault arcs on the energy balance is introduced into the arc model by using the net emission coefficient as a function of gas density, arc temperature and arc radius. The results for a test container show that factors such as the kinds of insulating gases and of electrode materials, the size of test vessels and the gas density considerably influence the thermal transfer coefficient and thus the pressure rise. Furthermore, it is demonstrated, for an example of the arc fault in a compact medium-voltage station with pressure relief openings and a pressure relief channel, that the arc energy and the arc temperature can be simulated based on the changing gas density.

  16. A RF time domain approach for electric arcs detection and localization systems

    Science.gov (United States)

    Deacu, Daniela; Tamas, Razvan; Petrescu, Teodor; Paun, Mirel; Anchidin, Liliana; Algiu, Madalina

    2016-12-01

    In this paper we propose a new method for detection and localization of electric arcs by using two ultra-wide band (UWB) antennas together with data processing in the time-domain. The source of electric arcs is localized by computing an average on the inter-correlation functions of the signals received on two channels. By calculating the path length difference to the antennas, the direction of the electric arcs is then found. The novelty of the method consists in the spatial averaging in order to reduce the incertitude caused by the finite sampling rate.

  17. Hydrometallurgically recovering zinc from electric arc furnace dusts

    Science.gov (United States)

    Antrekowitsch, J.; Antrekowitsch, H.

    2001-12-01

    The increasing use of zinc-containing scrap for steel production has lead to a high zinc content in the electric arc furnace and converter flue dusts. The cost of disposing of this residue is high due to environmental restrictions. Various recycling processes have been developed for these dusts, but most never reached the pilot plant stage and many investigations were stopped because of metallurgical and economical inefficiencies. While pyrometallurgical methods have to deal with high energy consumption, low zinc yield, and valueless residues, hydrometallurgical processes could offer an economical recycling alternative. This paper describes hydrometallurgical methods for recovering zinc from steel industry dust. These methods can be integrated in the primary zinc-winning process or in galvanization. Investigations of sulfuric-acid leaching show high zinc solubility but also a high iron content in the final liquor. As a result, steps for purification are required that cannot be conducted economically. Alternatively, a NaOH leaching gives a satisfying zinc yield and a very low solubility for the iron that remains in the residue.

  18. Phosphorus removal by electric arc furnace steel slag adsorption

    Science.gov (United States)

    Lim, J. W.; Lee, K. F.; Chong, Thomas S. Y.; Abdullah, L. C.; Razak, M. A.; Tezara, C.

    2017-10-01

    As to overcome the eutrophication in lakes and reservoirs which is resulted from excessive input of phosphorus due to rapid urbanization or uncontrolled agricultural activities, Electric Arc Furnace steel slag (EAFS), a steelmaking by-product, in which the disposal of this industrial waste considered economically unfavourable yet it’s physical and chemical properties exhibits high potential to be great P adsorbent. The objective of this study was to identify most suitable mathematical model in description of adsorption by using traditional batch experiment and to investigate the effect on Phosphorus removal efficiency and Phosphorus removal capacity by EAFS adsorption through variation of parameters such as pH, size of slag and initial concentration of Phosphorus. Result demonstrated that, Langmuir is suitable in describing Phosphorus removal mechanisms with the Maximum Adsorption Capacity, Q m of 0.166 mg/g and Langmuir Constant, KL of 0.03519 L/mg. As for effect studies, smaller size of adsorbent shows higher percentage (up to 37.8%) of Phosphorus removal compared to the larger size. Besides that, the experiment indicated a more acidic environment is favourable for Phosphorus removal and the amount of Phosphorus adsorbed at pH 3.0 was the highest. In addition, the adsorption capacity increases steadily as the initial Phosphorus concentration increases but it remained steady at 100mg P/L. Eventually, this study serves as better understanding on preliminary studies of P removal mechanisms by EAFS.

  19. Emissions of dioxin and dibenzofuran from electric arc furnaces

    Directory of Open Access Journals (Sweden)

    Figueira, S. L.

    2005-06-01

    Full Text Available This paper describes work done in order to clarify the formation mechanism of highly toxic micropoUutants, such as dioxins and dibenzofurans, from electric arc furnaces used in the production of carbon steel from scrap. The study is allowing to derive relationships between the levels of airborne micropoUutants and the operational parameters of the production process so that an abatement of pollution could be achieved. By using the European standard method CEN 1948 for dioxin like compounds sampling and measurement, it was possible to determine the characteristic fingerprint of micropoUutants emitted by this particular stationary source.

    Este artículo contiene resultados del trabajo ejecutado para el esclarecimiento de los mecanismos de formación de los micropolutantes muy tóxicos, como dioxinas y dibenzofuranos, que son emitidos por los hornos de arco eléctrico utilizados en la producción de acero. Estos estudios han permitido relacionar las concentraciones de polutantes emitidos a la atmósfera con las condiciones operación del homo eléctrico. Utilizando el método normalizado CEN 1948 para captación y análisis de muestras de compuestos análogos a las dioxinas ha sido posible determinar el perfil característico de los micropolutantes emitidos por esta fuente

  20. Influence of contact materials on phenomena in a short electrical arc

    International Nuclear Information System (INIS)

    Kharin, S.N.; Sarsengeldin, M.

    2011-01-01

    Investigation of transition phenomena accompanying the evolution of metallic phase of electric arc into gaseous phase is very important for the further progress in such fields as plasma technologies, electrical apparatus, plasmatrons and other technical applications. Some aspects of this transition are considered in presented paper on the base of mathematical model described dynamics of phenomena in the arc column, near-electrode zones, anode and cathode solids. Cathode and anode phenomena such as ion bombardment, thermionic emission, inverse electron flux, evaporation, radiation, heat conduction etc. are considered in dependence on time, current, opening velocity, parameters of the gas and contact materials. The conditions of the arc transition from one phase to another are formulated in terms of above characteristics and increasing of gas ionization level. Special experiments with two contacts materials, and have been carried to verify the mathematical model. The results of calculation and experimental data enables us to conclude that in metallic arc phase (short arc length), which is characterized by material transfer from the anode to the cathode, the erosion of contacts is considerably small than erosion of contacts both for resistive and inductive circuits, while in gaseous arc phase (long arc length) with opposite material transfer the rate of erosion depends on the inductance. If the inductance, then contacts have smaller erosion in comparison with contacts, however for inductive circuits situation is quite different, thus use of contacts in the case of long arcs burning in gaseous phase is more preferable. It was found also that the addition of niobium diselenide (1%) and tantalum (5%) into silver contact material which are sublimating into arc plasma enables to change ionization potential, that leads to decreasing of the arc temperature, arc duration and contact erosion. (author)

  1. Swarm observation of field-aligned current and electric field in multiple arc systems

    Science.gov (United States)

    Wu, J.; Knudsen, D. J.; Gillies, M.; Donovan, E.; Burchill, J. K.

    2017-12-01

    It is often thought that auroral arcs are a direct consequence of upward field-aligned currents. In fact, the relation between currents and brightness is more complicated. Multiple auroral arc systems provide and opportunity to study this relation in detail. In this study, we have identified two types of FAC configurations in multiple parallel arc systems using ground-based optical data from the THEMIS all-sky imagers (ASIs), magnetometers and electric field instruments onboard the Swarm satellites during the period from December 2013 to March 2015. In type 1 events, each arc is an intensification within a broad, unipolar current sheet and downward currents only exist outside the upward current sheet. These types of events are termed "unipolar FAC" events. In type 2 events, multiple arc systems represent a collection of multiple up/down current pairs, which are termed as "multipolar FAC" events. Comparisons of these two types of FAC events are presented with 17 "unipolar FAC" events and 12 "multipolar FAC" events. The results show that "unipolar FAC" and "multipolar FAC" events have systematic differences in terms of MLT, arc width and separation, and dependence on substorm onset time. For "unipolar FAC" events, significant electric field enhancements are shown on the edges of the broad upward current sheet. Electric field fluctuations inside the multiple arc system can be large or small. For "multipolar FAC" events, a strong correlation between magnetic and electric field indicate uniform conductance within each upward current sheet. The electrodynamical structures of multiple arc systems presented in this paper represents a step toward understanding arc generation.

  2. Modelling and simulation of unsteady dc electric arcs and their interactions with electrodes

    Science.gov (United States)

    Chemartin, L.; Lalande, P.; Delalondre, C.; Cheron, B.; Lago, F.

    2011-05-01

    This paper is devoted to the study of unsteady electric arcs and the effects of electrodes on their dynamics. One of the objectives is to simulate and understand the three-dimensional behaviour of arcs in complex geometries, which create important fluctuations of the column and reattachments on the electrodes. The usual methods to solve the problem of arc-electrodes coupling are not suitable to simulate three-dimensional unsteady arcs. We propose a numerical development to simulate both steady-state and unsteady arcs without additional assumptions. The method is based on the incorporation of electrodes into the computational domain. It is validated with measurements from the literature, in the case of a point-plane steady-state argon arc. The model is used to study the lightning certification test device, which simulates in laboratory the effects of lightning arcs on fuselage panels. The results bring to light, in agreement with the observations in laboratory, the fundamental role of the electrodes on the three-dimensional behaviour of the arc column. The model is also used to simulate the development of the free jet of a plasma on an aluminium planar anode. The objective is to characterize the interaction region and the thermal constraint of the arc.

  3. Process stability during fiber laser-arc hybrid welding of thick steel plates

    Science.gov (United States)

    Bunaziv, Ivan; Frostevarg, Jan; Akselsen, Odd M.; Kaplan, Alexander F. H.

    2018-03-01

    Thick steel plates are frequently used in shipbuilding, pipelines and other related heavy industries, and are usually joined by arc welding. Deep penetration laser-arc hybrid welding could increase productivity but has not been thoroughly investigated, and is therefore usually limited to applications with medium thickness (5-15 mm) sections. A major concern is process stability, especially when using modern welding consumables such as metal-cored wire and advanced welding equipment. High speed imaging allows direct observation of the process so that process behavior and phenomena can be studied. In this paper, 45 mm thick high strength steel was welded (butt joint double-sided) using the fiber laser-MAG hybrid process utilizing a metal-cored wire without pre-heating. Process stability was monitored under a wide range of welding parameters. It was found that the technique can be used successfully to weld thick sections with appropriate quality when the parameters are optimized. When comparing conventional pulsed and the more advanced cold metal transfer pulse (CMT+P) arc modes, it was found that both can provide high quality welds. CMT+P arc mode can provide more stable droplet transfer over a limited range of travel speeds. At higher travel speeds, an unstable metal transfer mechanism was observed. Comparing leading arc and trailing arc arrangements, the leading arc configuration can provide higher quality welds and more stable processing at longer inter-distances between the heat sources.

  4. OPTIMAL CONTROL FOR ELECTRIC VEHICLE STABILIZATION

    Directory of Open Access Journals (Sweden)

    MARIAN GAICEANU

    2016-01-01

    Full Text Available This main objective of the paper is to stabilize an electric vehicle in optimal manner to a step lane change maneuver. To define the mathematical model of the vehicle, the rigid body moving on a plane is taken into account. An optimal lane keeping controller delivers the adequate angles in order to stabilize the vehicle’s trajectory in an optimal way. Two degree of freedom linear bicycle model is adopted as vehicle model, consisting of lateral and yaw motion equations. The proposed control maintains the lateral stability by taking the feedback information from the vehicle transducers. In this way only the lateral vehicle’s dynamics are enough to considerate. Based on the obtained linear mathematical model the quadratic optimal control is designed in order to maintain the lateral stability of the electric vehicle. The numerical simulation results demonstrate the feasibility of the proposed solution.

  5. Integrated parametric study of a hybrid-stabilized argon–water arc under subsonic, transonic and supersonic plasma flow regimes

    Czech Academy of Sciences Publication Activity Database

    Jeništa, Jiří; Takana, H.; Nishiyama, H.; Bartlová, M.; Aubrecht, V.; Křenek, Petr; Hrabovský, Milan; Kavka, Tetyana; Sember, Viktor; Mašláni, Alan

    2011-01-01

    Roč. 44, č. 43 (2011), s. 435204-435204 ISSN 0022-3727 R&D Projects: GA ČR GAP205/11/2070 Institutional research plan: CEZ:AV0Z20430508 Keywords : hybrid-stabilized electric arc * mass flow rate * net emission coefficients * partial characteristics * Mach number * shock diamonds Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.544, year: 2011 http://iopscience.iop.org/0022-3727/44/43/435204/pdf/0022-3727_44_43_435204.pdf

  6. Magnetic and electric properties of C-Co thin films prepared by vaccum arc technique

    Energy Technology Data Exchange (ETDEWEB)

    Tembre, A.; Clin, M.; Picot, J.-C. [Laboratoire de Physique de la Matiere Condensee, Universite de Picardie Jules Verne, 33 rue Saint Leu, 80039 Amiens (France); Dellis, J.-L., E-mail: jean-luc.dellis@u-picardie.fr [Laboratoire de Physique de la Matiere Condensee, Universite de Picardie Jules Verne, 33 rue Saint Leu, 80039 Amiens (France); Henocque, J. [Laboratoire de Physique de la Matiere Condensee, Universite de Picardie Jules Verne, 33 rue Saint Leu, 80039 Amiens (France); Bouzerar, R. [Laboratoire de Physique des Systemes Complexes, Universite de Picardie Jules Verne, 33 rue Saint leu, 80039 Amiens (France); Djellab, K. [Plate-forme de Microscopie Electronique, Universite de Picardie Jules Verne, 33 rue Saint Leu, 80039 Amiens (France)

    2011-09-15

    Highlights: > Cobalt doped carbon thin films have been deposited by pulsed anodic electric arc technique. > The films are composed of well-crystallized cobalt layers and complex graphitic microstructure. > An insulating to a metallic state transition at 60 K is observed. > The magnetic susceptibility measurements show anomalous behaviour around 60 K. - Abstract: Cobalt doped carbon thin films have been deposited by a pulsed anodic electric arc technique. The films were characterized by high resolution transmission electron microscopy, electric measurements under dc magnetic fields, and ac magnetic susceptibility measurements within a temperature range 15-300 K. An insulating to a metallic state transition at a critical temperature around 60 K was observed.

  7. Linearized Model of Electrical Arc Furnace Suitable for Analysis of Flicker Mitigation

    Czech Academy of Sciences Publication Activity Database

    Valouch, Viktor

    2003-01-01

    Roč. 48, č. 2 (2003), s. 147-156 ISSN 0001-7043 R&D Projects: GA AV ČR IAA2057301 Institutional research plan: CEZ:AV0Z2057903 Keywords : flicker * electrical arc furnace * unified power quality conditioner Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  8. The Stability of Arc Attachment in Arcjet Propulsion Devices.

    Science.gov (United States)

    1997-01-01

    operated at low power levels. However, it is desirable to increase the performance and operating range of the arcjet so that they may run more efficiently and reliably and be applicable to a wider set of missions....The design of high current plasma devices such as arcjet thrusters, arc heaters, magnetohydrodynamic generators, and plasma opening switches has in...the past been based mostly on empirical methods. In the case of arcjet thrusters, these methodologies have produced a steady, reliable device when

  9. Coupled simulations of electric arcs for switching devices with MpCCI and ANSYS

    OpenAIRE

    Bayrasy, Pascal

    2016-01-01

    Electric arcs occur in various industrial applications from melting, welding, and lighting to switching devices. The discharge phenomenon is governed by the magneto-hydrodynamic equations, considering the Lorentz forces, Ohmic heating and radiation transport. The resulting arc is coupled with the dynamics of the compressible flow of the gas. This simulation procedure is well established in the swichting devices industry. In the present case a multi-physics framework solution MpCCI is applied ...

  10. Is electric arc welding linked to manganism or Parkinson's disease?

    Science.gov (United States)

    McMillan, Grant

    2005-01-01

    Manganese and its inorganic compounds are widely used in many industries and have been accepted as occupational neurotoxins that have caused a distinct and disabling clinical entity, manganism, in several types of work, notably where exposure is by way of dust. There is inconclusive and inconsistent evidence that, in these occupations, subclinical neurological effects, detectable only by neurobehavioural studies, may be caused by low doses. This has prompted a re-evaluation of occupational exposure limits. Some countries, including the UK, already demand much higher levels of protection against exposure than 5 years ago. Welding is the most common source of occupational exposure as manganese is an essential component of steel and so its compounds are inevitable components of fume emitted from steel welding processes. There it is found in respirable particles, often as complex oxides (spinels), sometimes within a core protected by a silicon oxide shell - as distinct from the much simpler form of particle formed by disintegration in processes such as mining and ore milling where manganism has been diagnosed convincingly. Millions of workers are at risk of exposure to manganese-containing compounds in fumes from electric arc welding of steel. In recent years it has been asserted that neurological and neurobehavioural disorders may develop consequent to exposure to steel welding fumes and that employment as a welder is associated with the unusually early onset of Parkinson's disease. Causal relationships have been postulated. Welders have been recorded as having been exposed to high levels of manganese-containing fume, especially where they have worked in confined, unventilated spaces, although this appears from limited data to be the exception rather than the rule. Even then the dose received is generally less than in mining or ore crushing. When care is taken to exclude exposures from hardfacing and burning and cutting arc processes, where manganese may form a high

  11. Active control of massively separated high-speed/base flows with electric arc plasma actuators

    Science.gov (United States)

    DeBlauw, Bradley G.

    The current project was undertaken to evaluate the effects of electric arc plasma actuators on high-speed separated flows. Two underlying goals motivated these experiments. The first goal was to provide a flow control technique that will result in enhanced flight performance for supersonic vehicles by altering the near-wake characteristics. The second goal was to gain a broader and more sophisticated understanding of these complex, supersonic, massively-separated, compressible, and turbulent flow fields. The attainment of the proposed objectives was facilitated through energy deposition from multiple electric-arc plasma discharges near the base corner separation point. The control authority of electric arc plasma actuators on a supersonic axisymmetric base flow was evaluated for several actuator geometries, frequencies, forcing modes, duty cycles/on-times, and currents. Initially, an electric arc plasma actuator power supply and control system were constructed to generate the arcs. Experiments were performed to evaluate the operational characteristics, electromagnetic emission, and fluidic effect of the actuators in quiescent ambient air. The maximum velocity induced by the arc when formed in a 5 mm x 1.6 mm x 2 mm deep cavity was about 40 m/s. During breakdown, the electromagnetic emission exhibited a rise and fall in intensity over a period of about 340 ns. After breakdown, the emission stabilized to a near-constant distribution. It was also observed that the plasma formed into two different modes: "high-voltage" and "low-voltage". It is believed that the plasma may be switching between an arc discharge and a glow discharge for these different modes. The two types of plasma do not appear to cause substantial differences on the induced fluidic effects of the actuator. In general, the characterization study provided a greater fundamental understanding of the operation of the actuators, as well as data for computational model comparison. Preliminary investigations

  12. Thermal radiation effect on the extinction properties of electric arcs in HV circuit breakers

    Directory of Open Access Journals (Sweden)

    Ziani Abderrahmane

    2009-01-01

    Full Text Available During the formation of the electric arc at the opening of a high voltage circuit breaker, the generated plasma will be the seat of a very important thermal exchange. Models founded only on conduction and convection thermal transfers don't reproduce the whole thermal exchanges that are governing the extinction process. This paper is devoted to the development of a model of the electric arc extinction in a high voltage circuit breaker taking in account the thermal radiation of the plasma, in addition to the conduction and convection phenomena. The Stefan-Boltzman equation is coupled with the heat equation, and both equations are solved simultaneously in order to follow the evolution of the arc voltage and the conductance of the thermal plasma. The obtained results are found in good agreement with experimental recordings.

  13. Application of Optical Spectrophotometry for Analysis of Radiation Spectrum Emitted by Electric Arc in the Air

    Directory of Open Access Journals (Sweden)

    Michał Kozioł

    2016-01-01

    Full Text Available This paper presents the results of measurement and analysis of optical radiation emitted by a free burning electric arc. The aim was to determine the application possibilities of optical spectrophotometry for detection of electric arcs. The research works considered electric arc generated with a constant voltage supply between two copper electrodes in the air, carried out under laboratory conditions. A high resolution optical spectrophotometer was used for registration of optical radiation. The analyses involved determination of two dimensionless descriptors obtained for the gathered spectra. Moreover, for each of the registered intensity distributions, the energy values were calculated for three frequency ranges. Based on the measured signals, the possibility of application of spectrophotometry for the optical radiation analysis was confirmed. The analysis indicated that the most energy of optical radiation is detected for the range of 200–780 nm, while above 780 nm almost no optical energy is emitted. Spectrophotometric studies performed in the UV-NIR range are of interest since one can obtain information about the structural defects (at lower wavebands or impurities and/or point defects (at low energies bands. It was also stated that the obtained descriptors may be applied for diagnosis and identification of electric arc purposes.

  14. suitability of electric arc furnace (eaf) slag as partial replacement for ...

    African Journals Online (AJOL)

    Administrator

    The use of Electric Arc Furnace (EAF) Slag which is a by-product solid waste in Steel Production was investigated for use as a partial replacement for cement in sandcrete blocks. The tests carried out on cement and finely ground slag to determine their compositions and physico-chemical properties as well as the evaluation ...

  15. Suitability of electric arc furnace (eaf) slag as partial replacement for ...

    African Journals Online (AJOL)

    The use of Electric Arc Furnace (EAF) Slag which is a by-product solid waste in Steel Production was investigated for use as a partial replacement for cement in sandcrete blocks. The tests carried out on cement and finely ground slag to determine their compositions and physico-chemical properties as well as the evaluation ...

  16. Electrical and thermal finite element modeling of arc faults in photovoltaic bypass diodes.

    Energy Technology Data Exchange (ETDEWEB)

    Bower, Ward Isaac; Quintana, Michael A.; Johnson, Jay

    2012-01-01

    Arc faults in photovoltaic (PV) modules have caused multiple rooftop fires. The arc generates a high-temperature plasma that ignites surrounding materials and subsequently spreads the fire to the building structure. While there are many possible locations in PV systems and PV modules where arcs could initiate, bypass diodes have been suspected of triggering arc faults in some modules. In order to understand the electrical and thermal phenomena associated with these events, a finite element model of a busbar and diode was created. Thermoelectrical simulations found Joule and internal diode heating from normal operation would not normally cause bypass diode or solder failures. However, if corrosion increased the contact resistance in the solder connection between the busbar and the diode leads, enough voltage potentially would be established to arc across micron-scale electrode gaps. Lastly, an analytical arc radiation model based on observed data was employed to predicted polymer ignition times. The model predicted polymer materials in the adjacent area of the diode and junction box ignite in less than 0.1 seconds.

  17. Characterization of the behaviour of the electric arc during VAR of a Ti alloy

    Science.gov (United States)

    Chapelle, P.; Noël, C.; Risacher, A.; Jourdan, J.; Jourdan, J.; Jardy, A.

    2016-07-01

    In this paper, we report experimental results based on the direct observation of the electric arc behaviour during vacuum arc remelting of a Ti alloy. These results were obtained in a specifically instrumented industrial furnace using high speed framing camera and optical emission spectroscopy, for a current density level of the order of 10 A/cm2 and a gap length of a few centimetres. It was observed that the arc exhibits a similar operating regime to that described in the literature for the case of Inconel 718 and Zr alloy electrodes. The arc structure corresponds essentially to that of a diffuse metal vapor arc with separate and rapidly moving cathode spots. Several critical parameters of the cathode spots, including their current, size and velocity, and of the interelectrode plasma were evaluated. Also, the interactions between the arc operation and the transfer of metal drops in the interelectrode gap were investigated. Three modes of transfer of the liquid metal drops in the interelectrode gap have been identified depending on the gap length: drop falling, drip short and drop erosion induced by the cathode spots.

  18. Evaluation of ocular hazards due to electric arc flash at an in-line switch.

    Science.gov (United States)

    Chou, B R; Cullen, A P

    1991-10-01

    We investigated the ocular damage resulting from operation of a solid blade pole-mounted in-line electrical switch at between 16 and 17 kV with current loads between 38 A and 340 A. Spectroradiometric data for the electric arcs produced as the switch was opened were obtained over the waveband 200 to 1500 nm. The eyes of adult pigmented rabbits were exposed to the arc flash at a distance of 2 m. The ocular tissues were assessed clinically and histologically up to 48 h postexposure. Threshold damage was clinically detectable only in eyes exposed to a 340 A arc. We conclude that at the normal current loads on a 17-kV electric power transmission line, the principal oculovisual hazards are due to molten metal fulminated from the switch by the arc, and after-images due to the bright visible light flash. At a working distance of 2 m, the ultraviolet ocular hazard is negligible. Adequate eye protection is provided by clear polycarbonate safety lenses.

  19. The electrical characteristics of copper slags in a 270 kVA DC arc furnace

    International Nuclear Information System (INIS)

    Derin, Bora; Sahin, Filiz Cinar; Yucel, Onuralp

    2003-01-01

    The electrical resistance of slags is the main criteria to determine the design and the operation conditions of slag resistance furnace (SRF) depending on temperature and composition. In this study, a 270 kVA DC electric arc furnace were used to determine the electrical characteristic of molten ancient copper slags. The specific conductivity of the slag was estimated by using furnace geometric factor given in the literature as an empirical formula and by using furnace resistance measured during smelting of the copper slag with or without different additives such as coke, CaO and Al 2 O 3 . (Original)

  20. Test plan for BWID Phase 2 electric arc melter vitrification tests

    Energy Technology Data Exchange (ETDEWEB)

    Soelberg, N.R.; Turner, P.C.; Oden, L.L.; Anderson, G.L.

    1994-10-01

    This test plan describes the Buried Waste Integrated Demonstration (BWID), Phase 2, electric arc melter, waste treatment evaluation tests to be performed at the US Bureau of Mines (USBM) Albany Research Center. The BWID Arc Melter Vitrification Project is being conducted to evaluate and demonstrate existing industrial arc melter technology for thermally treating mixed transuranic-contaminated wastes and soils. Phase 1 baseline tests, performed during fiscal year 1993 at the USBM, were conducted on waste feeds representing incinerated buried mixed wastes and soils. In Phase 2, surrogate feeds will be processed that represent actual as-retrieved buried wastes from the Idaho National Engineering Laboratory`s Subsurface Disposal Area at the Radioactive Waste Management Complex.

  1. IRON ORE SINTER PRODUCTION USING ELECTRIC ARC FURNACE DUST AS RAW MATERIAL

    Directory of Open Access Journals (Sweden)

    Victor Bridi Telles

    2013-03-01

    Full Text Available The steel production through Electric Arc Furnaces (EAF generates approximately 15% to 20% of Electric Arc Furnace Dust (EAFD. This waste is considered dangerous due to the presence of metals as lead and cadmium that leach in contact with water. Because of this, the EAFD recycling becomes an alternative to diminish the costs with landfills and environmental harms caused by the waste. The iron ore sintering is a process that reuses most part of powders generated by the steelmaking. However the EAFD is not reused in this process because it contains zinc. The zinc is highly detrimental inside blast furnaces causing heavy crusts and affecting the thermodynamic equilibrium of the process. Therefore, this work studies the EAFD reuse in the iron ore sintering process to produce iron ore sinter with zinc contents between the limits established for blast furnaces.

  2. Skid resistance performance of asphalt wearing courses with electric arc furnace slag aggregates.

    Science.gov (United States)

    Kehagia, Fotini

    2009-05-01

    Metallurgical slags are by-products of the iron and steel industry and are subdivided into blast furnace slag and steel slag according to the different steel-producing processes. In Greece, slags are mostly produced from steelmaking using the electric arc furnace process, and subsequently are either disposed in a random way or utilized by the cement industry. Steel slag has been recently used, worldwide, as hard aggregates in wearing courses in order to improve the skidding resistance of asphalt pavements. At the Highway Laboratory, Department of Civil Engineering of Aristotle University of Thessaloniki research has been carried out in the field of steel slags, and especially in electric arc furnace (EAF) slag, to evaluate their possible use in highway engineering. In this paper, the recent results of anti-skidding performance of steel slag aggregates in highway pavements are presented.

  3. Temperature estimation of liquid steel in electric arc furnaces; Schaetzung der Stahlbadtemperatur im Lichtbogenofen

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Matthias; Krueger, Klaus [Helmut-Schmidt-Univ./Univ. der Bundeswehr, Hamburg (Germany); Juechter, Ansgar; Braun, Uwe [ArcelorMittal Hamburg GmbH, Hamburg (Germany)

    2011-12-15

    One criterion for an energy-optimized operation of electric arc furnaces is to reach the required tapping temperature precisely. The related, partially manual measurement of the melt temperature is carried out with disposable thermocouples. This process is time-consuming and expensive. Therefore development target is to predict the temperature of the liquid steel by using theoretical models. This paper will present different methods for estimating the melt temperature. (orig.)

  4. The role of radiation loses in high-pressure blasted electrical arcs

    Czech Academy of Sciences Publication Activity Database

    Gregor, J.; Jakubová, I.; Šenk, J.; Mašláni, Alan

    2011-01-01

    Roč. 275, č. 1 (2011), 012007-012007 E-ISSN 1742-6596. [European Conference on High-Technology Plasma Processes (HTPP 11)/11th./. Brussels, 27.06.2010-02.07.2010] Institutional research plan: CEZ:AV0Z20430508 Keywords : High-pressure electrical arc * radiation loss * mathematical model Subject RIV: BL - Plasma and Gas Discharge Physics http://iopscience.iop.org/1742-6596/275/1/012007/pdf/1742-6596_275_1_012007.pdf

  5. EFFICIENT USE OF ENERGY IN A ELECTRIC ARC FURNANCE BY HEAT INTEGRATION APPROACH

    OpenAIRE

    Umesh Kumar, Dr. A K Prasad, Sourabh Kumar Soni

    2016-01-01

    Based on the principles of heat integration, the present work investigates the design and operational modifications which can lead to efficient energy integration in an electric arc furnace being operated with direct reduction process. This process is one of the oldest and most widely applied processes amongst the commercially used process in India. For the purpose of energy integration stream data is extracted from the actual flow sheet of the plant, which consists of supply and target tempe...

  6. Imaging of Vector Electric Fields Surrounding Auroral Arcs from Multibeam Incoherent Scatter Radar Measurements.

    Science.gov (United States)

    Maksimova, N.; Varney, R. H.; Cosgrove, R. B.; Kaeppler, S. R.; Nicolls, M. J.

    2015-12-01

    Evaluating the ionospheric electric fields and current systems surrounding auroral arcs aids in distinguishing physical mechanisms that drive arc generation and current closure. Auroral forms involve spatial scales that are small in comparison with the magnetosphere-ionosphere-thermosphere (MIT) system, and yet these forms are thought to be closely tied to the overall system response. Spatially resolved measurements of the horizontal ionospheric current can, in principle, be used to determine the field-aligned currents (FAC) that are responsible for energy transfer between the magnetosphere and the ionosphere/thermosphere, leading to heating and upwelling of the neutral gas and acceleration of ion upflows and outflows. Furthermore, the closure of FACs in the ionosphere regulates modes of magnetospheric convection and substorms. An algorithm has been developed to image the local structure in the convection electric field using multibeam incoherent scatter radar (ISR) measurements. Given the inherent difficulty of reconstructing vector quantities from line of sight (LOS) velocity measurements, the algorithm's aim is to select from the solution space for the possible field configurations a unique solution for the electric field distribution by constraining the reconstructed electric field to reproduce the LOS measurements within measurement errors while simultaneously minimizing a measure of the field's curvature and absolute gradient. Using the method of Lagrange multipliers, the algorithm regularizes the underdetermined problem defined by the LOS radar velocity measurements and guarantees a unique solution when the average measurement error is smaller than the average measurement amplitude. The algorithm is tested on a variety of simulated fields in a sensitivity study to determine the extent to which the solution depends on the a priori assumptions and the observation geometry. In addition, a case study of a quiescent auroral arc observed by the Poker Flat

  7. Characteristics of gas and residues produced from electric arc pyrolysis of waste lubricating oil.

    Science.gov (United States)

    Song, Geum-Ju; Seo, Yong-Chil; Pudasainee, Deepak; Kim, In-Tae

    2010-07-01

    An attempt has been made to recover high-calorific fuel gas and useful carbonaceous residue by the electric arc pyrolysis of waste lubricating oil. The characteristics of gas and residues produced from electric arc pyrolysis of waste lubricating oil were investigated in this study. The produced gas was mainly composed of hydrogen (35-40%), acetylene (13-20%), ethylene (3-4%) and other hydrocarbons, whereas the concentration of CO was very low. Calorific values of gas ranged from 11,000 to 13,000 kcal kg(-1) and the concentrations of toxic gases, such as NO(x), HCl and HF, were below the regulatory emissions limit. Gas chromatography-mass spectrometry (GC/MS) analysis of liquid-phase residues showed that high molecular-weight hydrocarbons in waste lubricating oil were pyrolyzed into low molecular-weight hydrocarbons and hydrogen. Dehydrogenation was found to be the main pyrolysis mechanism due to the high reaction temperature induced by electric arc. The average particle size of soot as carbonaceous residue was about 10 microm. The carbon content and heavy metals in soot were above 60% and below 0.01 ppm, respectively. The utilization of soot as industrial material resources such as carbon black seems to be feasible after refining and grinding. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  8. Numerical modelling of an electric arc and its interaction with the anode: part II. The three-dimensional model-influence of external forces on the arc column

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, J J; Lago, F; Freton, P; Masquere, M; Franceries, X [CPAT, UMR CNRS 5002, Universite Paul Sabatier, 118 route de Narbonne, 31062 Toulouse (France)

    2005-01-21

    This paper reports the second part of the study of an electric arc and its interaction with the anode material. First, a three-dimensional model is presented and validated in a natural symmetric configuration for which many experimental results exist. In the three-dimensional model, two situations are considered for the anode surface: the classical zero heat flux condition and the use of the anode model. In the second case, the specific properties of the anode material are taken into account and play a role in the current conservation between the plasma and the anode, and therefore, affect the arc behaviour near the electrode. The results for the two approaches are similar in two dimensions, but differences exist in real three-dimensional cases when external forces such as cross flow or magnetic field tend to bend the arc. Second, we present a comparison between the two methods in the case where the arc is deviated by an external magnetic field. For this comparison, we adopt a configuration used at Odeillo during the 1970s and compare the results obtained by our code with the experimental ones. We find that it is essential to consider the complete anode model if the arc deflection is to be predicted correctly. Once our developments are validated, the computational code is applied in a free-burning arc configuration, where the plasma column is deflected by an external cross flow.

  9. Numerical modelling of an electric arc and its interaction with the anode: part II. The three-dimensional model-influence of external forces on the arc column

    International Nuclear Information System (INIS)

    Gonzalez, J J; Lago, F; Freton, P; Masquere, M; Franceries, X

    2005-01-01

    This paper reports the second part of the study of an electric arc and its interaction with the anode material. First, a three-dimensional model is presented and validated in a natural symmetric configuration for which many experimental results exist. In the three-dimensional model, two situations are considered for the anode surface: the classical zero heat flux condition and the use of the anode model. In the second case, the specific properties of the anode material are taken into account and play a role in the current conservation between the plasma and the anode, and therefore, affect the arc behaviour near the electrode. The results for the two approaches are similar in two dimensions, but differences exist in real three-dimensional cases when external forces such as cross flow or magnetic field tend to bend the arc. Second, we present a comparison between the two methods in the case where the arc is deviated by an external magnetic field. For this comparison, we adopt a configuration used at Odeillo during the 1970s and compare the results obtained by our code with the experimental ones. We find that it is essential to consider the complete anode model if the arc deflection is to be predicted correctly. Once our developments are validated, the computational code is applied in a free-burning arc configuration, where the plasma column is deflected by an external cross flow

  10. Numerical modelling of an electric arc and its interaction with the anode: part II. The three-dimensional model—influence of external forces on the arc column

    Science.gov (United States)

    Gonzalez, J. J.; Lago, F.; Freton, P.; Masquère, M.; Franceries, X.

    2005-01-01

    This paper reports the second part of the study of an electric arc and its interaction with the anode material. First, a three-dimensional model is presented and validated in a natural symmetric configuration for which many experimental results exist. In the three-dimensional model, two situations are considered for the anode surface: the classical zero heat flux condition and the use of the anode model. In the second case, the specific properties of the anode material are taken into account and play a role in the current conservation between the plasma and the anode, and therefore, affect the arc behaviour near the electrode. The results for the two approaches are similar in two dimensions, but differences exist in real three-dimensional cases when external forces such as cross flow or magnetic field tend to bend the arc. Second, we present a comparison between the two methods in the case where the arc is deviated by an external magnetic field. For this comparison, we adopt a configuration used at Odeillo during the 1970s and compare the results obtained by our code with the experimental ones. We find that it is essential to consider the complete anode model if the arc deflection is to be predicted correctly. Once our developments are validated, the computational code is applied in a free-burning arc configuration, where the plasma column is deflected by an external cross flow.

  11. Stability analysis of Centurion electric power system

    Energy Technology Data Exchange (ETDEWEB)

    Galu, Y.; Munda, J.L.; Jimoh, A.A. [Tshwane Univ. of Technology, Pretoria (South Africa)

    2008-07-01

    A Centurion electric power system was simulated. Data from a section of the Tshwane Municipality network in South Africa were used to evaluate the use of a power system stabilizer (PSS) and a flexible AC transmission system (FACTS) controller and a thyristor controlled series compensator (TCSC). The single-machine infinite bus (SMIB) power system model was used to validate the effectiveness of the systems under various disturbance scenarios. The system's synchronous generator was characterized as a higher order model. Thevenin's equivalent of the transmission network was used to reduce the single-machine infinite bus power system in relation to the reactance of the transformer, transmission line per circuit, and the impedance of the receiving end system. Three-phase faults were applied at the generator terminal busbar in order to evaluate the model's performance. The study demonstrated that use of the PSS and TCSC-based controllers provide an improved response in terms of both overshoot and settling time. 17 refs., 10 figs.

  12. Microhardness and tribological wear of the steels remelted with an electric arc

    Directory of Open Access Journals (Sweden)

    S. Adamiak

    2009-04-01

    Full Text Available This study presents results of a research on the surface strengthening of the C15, C45 and C90U steels by application of concentrated heat stream with the GTAW methodology. Utilizing the GTAW methodology remelting of the surface layer of the sampled steels was performed by a welding head moving at a speed ranging from 200 mm/min to 800 mm/min and the current intensity of the electric arcranging from 50A to 300A. Measurements of hardness, frictional coefficient and intensity of tribological wear were performed in theremelted surface layer. Correlation between the intensity of the electric arc versus microhardness and tribological wear resistance under conditions of dry-friction was established. Following the treatment an increase in hardness as well as increase in the tribological wear resistance could be observed in steel samples. The best results were achieved during remelting of the surface layer with electric arc at 100A intensity and the speed of the welding head in relation to treated sample of 200 mm/min.

  13. Charge on luminous bodies resembling natural ball lightning produced via electrical arcs through lump silicon

    Science.gov (United States)

    Porter, Christina L.; Miley, Galen P.; Griffiths, David J.; Sánchez, Erik

    2014-12-01

    A phenomenon resembling natural ball lightning can be produced via electrical arcing through silicon. We use lump silicon instead of silicon wafers to achieve higher production rates and larger, longer-lived luminous balls than previously reported. The luminous balls consist of a silicon core surrounded by a porous network of loosely bound silicon dioxide nanoparticles. We find that the balls carry a small net charge on the order of 10-12 C and propose that the nanoparticles are electrostatically bound to the core due to this charge.

  14. Growth of carbon nanotubes in arc plasma treated graphite disc: microstructural characterization and electrical conductivity study

    Science.gov (United States)

    Nayak, B. B.; Sahu, R. K.; Dash, T.; Pradhan, S.

    2018-03-01

    Circular graphite discs were treated in arc plasma by varying arcing time. Analysis of the plasma treated discs by field emission scanning electron microscope revealed globular grain morphologies on the surfaces, but when the same were observed at higher magnification and higher resolution under transmission electron microscope, growth of multiwall carbon nanotubes of around 2 nm diameter was clearly seen. In situ growth of carbon nanotube bundles/bunches consisting of around 0.7 nm tube diameter was marked in the case of 6 min treated disc surface. Both the untreated and the plasma treated graphite discs were characterized by X-ray diffraction, energy dispersive spectra of X-ray, X-ray photoelectron spectroscopy, transmission electron microscopy, micro Raman spectroscopy and BET surface area measurement. From Raman spectra, BET surface area and microstructure observed in transmission electron microscope, growth of several layers of graphene was identified. Four-point probe measurements for electrical resistivity/conductivity of the graphite discs treated under different plasma conditions showed significant increase in conductivity values over that of untreated graphite conductivity value and the best result, i.e., around eightfold increase in conductivity, was observed in the case of 6 min plasma treated sample exhibiting carbon nanotube bundles/bunches grown on disc surface. By comparing the microstructures of the untreated and plasma treated graphite discs, the electrical conductivity increase in graphite disc is attributed to carbon nanotubes (including bundles/bunches) growth on disc surface by plasma treatment.

  15. CHARACTERIZATION OF THE DUST GENERATED IN THE RECYCLING PROCESS OF THE ELECTRIC ARC FURNACE DUST

    Directory of Open Access Journals (Sweden)

    Fábio Gonçalves Rizz

    2013-10-01

    Full Text Available Electric Arc Furnace Dust (EAFD is a solid waste generated by the production of steel through the Electric Arc Furnace. This waste is labeled dangerous, which motivates studies aiming its recycling. Experiments were made to study a pyrometallurgical process for the recycling of the dust, using the insertion of dust briquettes in molten pig iron in three temperatures. In the briquettes, there were made additions of calcium fluoride in four different concentrations. This paper has the objective to characterize the dust that results from this process, verifying the influence of the temperature and the concentration of calcium fluoride in the briquette in the morphology and chemical composition of the new dust, determining the optimal conditions for the recovery of the zinc content of the dust. This newly generated dust was analyzed in an Scanning Electronic Microscope, used to capture micrographs and chemical composition by EDS. The micrographs show that the temperature and the calcium fluoride concentration interfere in the way the dust particles agglomerate. Chemical analysis points that the higher zinc recuperation occurrs in the experiments at 1500°C with 7% addition of calcium fluoride.

  16. Potential oxidative stress in the bodies of electric arc welding operators: effect of photochemical smog.

    Science.gov (United States)

    Zhu, You-Gen; Zhou, Jun-Fu; Shan, Wei-Ying; Zhou, Pei-Su; Tong, Gui-Zhong

    2004-12-01

    To investigate whether photochemical smog emitted during the process of electric arc welding might cause oxidative stress and potential oxidative damage in the bodies of welding operators. Seventy electric arc welding operators (WOs) and 70 healthy volunteers (HVs) were enrolled in a randomized controlled study design, in which the levels of vitamin C (VC) and vitamin E (VE) in plasma as well as the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), and the level of lipoperoxide (LPO) in erythrocytes were determined by spectrophotometry. Compared with the average values of the above experimental parameters in the HVs group, the average values of VC and VE in plasma as well as those of SOD, CAT and GPX in erythrocytes in the WOs group were significantly decreased (P smog the values of VC, VE, SOD, and GPX, except for CAT, in the WOs were decreased gradually (P smog in the bodies of WOs, thereby causing potential oxidative and lipoperoxidative damages in their bodies.

  17. An Alternative Cu-Based Bond Layer for Electric Arc Coating Process

    Science.gov (United States)

    Fadragas, Carlos R.; Morales, E. V.; Muñoz, J. A.; Bott, I. S.; Lariot Sánchez, C. A.

    2011-12-01

    A Cu-Al alloy has been used as bond coat between a carbon steel substrate and a final coating deposit obtained by applying the twin wire electric arc spraying coating technique. The presence of a copper-based material in the composite system can change the overall temperature profile during deposition because copper exhibits a thermal conductivity several times higher than that of the normally recommended bond coat materials (such as nickel-aluminum alloys or nickel-chromium alloys). The microstructures of 420 and 304 stainless steels deposited by the electric arc spray process have been investigated, focusing attention on the deposit homogeneity, porosity, lamellar structure, and microhardness. The nature of the local temperature gradient during deposition can strongly influence the formation of the final coating deposit. This study presents a preliminary study, undertaken to investigate the changes in the temperature profile which occur when a Cu-Al alloy is used as bond coat, and the possible consequences of these changes on the microstructure and adhesion of the final coating deposit. The influence of the thickness of the bond layer on the top coating temperature has also been also evaluated.

  18. PREFACE: 1st International Symposium on Electrical Arc and Thermal Plasmas in Africa (ISAPA)

    Science.gov (United States)

    Andre, Pascal; Koalaga, Zacharie

    2012-02-01

    Logos of the University of Ouagadougou, ISAPA and Universite Blaise Pascal Africa (especially Sub-Saharan Africa) is a continent where electrification is at a low level. However, the development of the electrical power sector is a prerequisite for the growth of other industrial activities, that is to say for the social and economic development of African countries. Consequently, a large number of electrification projects (rural electrification, interconnection of different country's grids) takes place in many countries. These projects need expertise and make Africa a continent of opportunity for companies in different domains for business and research: energy; energetic production, transmission, distribution and protection of electricity; the supply of cable; the construction, engineering and expertise in the field of solar and wind power. The first International Symposium on electrical Arc and thermal Plasma in Africa (ISAPA) was held for the first time in Ouagadougou, Burkina Faso to progress and develop the research of new physical developments, technical breakthroughs, and ideas in the fields of electrical production and electrical applications. The ISAPA aims to encourage the advancement of the science and applications of electrical power transformation in Africa by bringing together specialists from many areas in Africa and the rest of the world. Such considerations have led us to define a Scientific Committee including representatives from many countries. This first meeting was an innovative opportunity for researchers and engineers from academic and industrial sectors to exchange views and knowledge. Both fundamental aspects such as thermal plasma, electrical arc, diagnostics and applied aspects as circuit breakers, ICP analyses, photovoltaic energy conversion and alternative energies, as well as space applications were covered. The Laboratory of Material and Environment (LAME) from Ouagadougou University and the Laboratory of Electric Arc and Thermal

  19. Optimal Design of TCR/FC in Electric Arc Furnaces for Power Quality Improvement in Power Systems

    Directory of Open Access Journals (Sweden)

    Mahdi TORABIAN ESFAHANI

    2009-12-01

    Full Text Available Electric Arc Furnaces (EAFs are unbalanced, nonlinear and time varying loads, which can cause many problems in the power system quality. As the use of arc furnace loads increases in industry, the importance of the power quality problems also increase. So in order to optimize the usages of electric power in EAFs, it is necessary to minimize the effects of arc furnace loads on power quality in power systems as much as possible. Therefore, in this paper, design and simulation of an electric plant supplying an arc furnace is considered. For this purpose, a three phase arc furnace model, which can simulate all the mentioned power quality indices, is developed based on Hyperbolic -Exponential model (V-I model. Then by considering the high changes of reactive power and voltage flicker of nonlinear furnace load, a thyristor controlled reactor compensation with fixed capacitor (TCR/FC are designed and simulated. In this procedure, the reactive power is measured so that maximum speed and accuracy are achieved. Finally, simulation results verify the accuracy of the load modelling and show the effectiveness of the proposed TCR/FC model for reactive compensating of the EAF.

  20. DC Electric Arc Furnace Application for Production of Nickel-Boron Master Alloys

    Science.gov (United States)

    Alkan, Murat; Tasyürek, Kerem Can; Bugdayci, Mehmet; Turan, Ahmet; Yücel, Onuralp

    2017-09-01

    In this study, nickel-boron (Ni-B) alloys were produced via a carbothermic reduction starting from boric acid (H3BO3) with high-purity nickel oxide (NiO), charcoal, and wood chips in a direct current arc furnace. In electric arc furnace experiments, different starting mixtures were used, and their effects on the chemical compositions of the final Ni-B alloys were investigated. After the reduction and melting stages, Ni-B alloys were obtained by tapping from the bottom of the furnace. The samples from the designated areas were also taken and analyzed. The chemical composition of the final alloys and selected samples were measured with wet chemical analysis. The Ni-B alloys had a composition of up to 14.82 mass% B. The phase contents of the final alloys and selected samples were measured using x-ray diffraction (XRD). The XRD data helped predict possible reactions and reaction mechanisms. The material and energy balance calculations were made via the XRD Rietveld and chemical compositions. Nickel boride phases started to form 600 mm below the surface. The targeted NiB phase was detected at the tapping zone of the crucible (850-900 mm depth). The energy consumption was 1.84-4.29 kWh/kg, and the electrode consumption was 10-12 g/kg of raw material charged.

  1. The Interval Stability of an Electricity Market Model

    Directory of Open Access Journals (Sweden)

    Weijuan Wang

    2014-01-01

    Full Text Available Combined with the electric power market dynamic model put forward by Alvarado, an interval model of electricity markets is established and investigated in this paper pertaining to the range of demand elasticity with suppliers and consumers. The stability of an electricity market framework with demand elasticity interval is analyzed. The conclusions characterizing the interval model provided are derived by constructing a suitable Lyapunov function and using the theory of interval dynamical system in differential equations and matrix inequality theory and so forth. Applying the corollary obtained can judge the system stability by available data about demand elasticity. The obtained results are validated and illustrated by a case example.

  2. The thermal treatment of electric arc furnace dust under low gas phase pressure

    Directory of Open Access Journals (Sweden)

    W. Derda

    2009-04-01

    Full Text Available The paper presents the results of laboratory tests on the process of thermal reduction of electric arc furnace dust (EAFD in the temperature range from 1273 to 1473 K. Before proceeding to the experimental tests, a thermodynamic analysis was made using the computer program FactSage® with the aim of determining the optimal conditions for the dust components reduction reaction to proceed. The results of tests carried out, respectively, under atmospheric pressure conditions and under reduced pressure conditions are presented, where carbon in the form of graphite and blast-furnace dust (containing approx. 40 % of carbon was used as the reducer. The test results represent the effect of reduced pressure on the potential for intensifying the process of zinc removal from the dust. The degree of zinc extraction was considerably higher compared to the results of tests carried out under atmospheric pressure conditions.

  3. Reduction of electrical arc furnace oxidizing slag by coke under microwave irradiation

    Science.gov (United States)

    An, Sung Beom; Shin, Minsoo; Sim, Ki Joo; Lee, Joonho

    2014-03-01

    The reduction of iron from electrical arc furnace oxidizing slag by coke was investigated under microwave irradiation (1.7 kW, 2.45 GHz). The heating behavior of cokes of different sizes were examined and a maximum heating rate of 550 K/min and a maximum temperature of 1783 K were obtained with coke particles smaller than 75 m. In the reduction of the oxidizing slag (15 g) by coke (1.45˜1.65 g) under microwave irradiation for 25 min, the maximum recovery ratio of iron was 0.87, obtained when the amount of coke addition was 1.55 g. In addition, the reduced slag composition was modified by adding 5.9 g of CaO. With the addition of 1.55 g coke or more, free CaO in the slag was effectively reduced.

  4. Recycling of electric arc furnace dust; Reciclagem de poeira de aciaria eletrica

    Energy Technology Data Exchange (ETDEWEB)

    Marques Sobrinho, Vicente de Paulo Ferreira; Oliveira, Jose Roberto de, E-mail: vicente@ifes.edu.b [Instituto Federal de Ciencia e Tecnologia do Espirito Santo (IFES), Vitoria, ES (Brazil); Tenorio, Jorge Alberto Soares; Espinosa, Denise Crocce Romano [Universidade de Sao Paulo (EPUSP), SP (Brazil). Escola Politecnica

    2010-07-01

    This research aims to study the process of incorporation of the metal iron in electric arc furnace dust (EAFD), from a steel mill producing long steel by liquid iron in addition to the changing temperature of 1400 degrees Celsius of EAFD 'as received', the percentage of EAFD to be added (5, 10 and 20% of initial weight of sample pig iron) and the time of withdrawal of the sample of pig iron and slag (30 minutes after the addition of EAFD). Previously, the EAFD will be characterized using the following techniques: chemical analysis, size analysis, specific surface area, Xray diffraction, scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) microanalysis. . After characterization, the EAFD will be added to the bath of liquid pig iron. It is expected that the results obtained at the end of the research allow the evaluation of the iron metal incorporation of EAFD in pig iron bath. (author)

  5. Heavy metal recovery from electric arc furnace steel slag by using hydrochloric acid leaching

    Science.gov (United States)

    Wei, Lim Jin; Haan, Ong Teng; Shean Yaw, Thomas Choong; Chuah Abdullah, Luqman; Razak, Mus'ab Abdul; Cionita, Tezara; Toudehdehghan, Abdolreza

    2018-03-01

    Electric Arc Furnace steel slag (EAFS) is the waste produced in steelmaking industry. Environmental problem such as pollution will occur when dumping the steel slag waste into the landfill. These steel slags have properties that are suitable for various applications such as water treatment and wastewater. The objective of this study is to develop efficient and economical chlorination route for EAFS extraction by using leaching process. Various parameters such as concentration of hydrochloric acid, particle size of steel slag, reaction time and reaction temperature are investigated to determine the optimum conditions. As a result, the dissolution rate can be determined by changing the parameters, such as concentration of hydrochloric acid, particle size of steel slag, reaction time and reaction temperature. The optimum conditions for dissolution rates for the leaching process is at 3.0 M hydrochloric acid, particle size of 1.18 mm, reaction time of 2.5 hour and the temperature of 90°C.

  6. Electric field formation in three different plasmas: A fusion reactor, arc discharge, and the ionosphere

    Science.gov (United States)

    Lee, Kwan Chul

    2017-11-01

    Three examples of electric field formation in the plasma are analyzed based on a new mechanism driven by ion-neutral collisions. The Gyro-Center Shift analysis uses the iteration of three equations including perpendicular current induced by the momentum exchange between ions and neutrals when there is asymmetry over the gyro-motion. This method includes non-zero divergence of current that leads the solution of time dependent state. The first example is radial electric field formation at the boundary of the nuclear fusion device, which is a key factor in the high-confinement mode operation of future fusion reactors. The second example is the reversed rotation of the arc discharge cathode spot, which has been a mysterious subject for more than one hundred years. The third example is electric field formations in the earth's ionosphere, which are important components of the equatorial electrojet and black aurora. The use of one method that explains various examples from different plasmas is reported, along with a discussion of the applications.

  7. Optical emission spectroscopy of metal vapor dominated laser-arc hybrid welding plasma

    International Nuclear Information System (INIS)

    Ribic, B.; DebRoy, T.; Burgardt, P.

    2011-01-01

    During laser-arc hybrid welding, plasma properties affect the welding process and the weld quality. However, hybrid welding plasmas have not been systematically studied. Here we examine electron temperatures, species densities, and electrical conductivity for laser, arc, and laser-arc hybrid welding using optical emission spectroscopy. The effects of arc currents and heat source separation distances were examined because these parameters significantly affect weld quality. Time-average plasma electron temperatures, electron and ion densities, electrical conductivity, and arc stability decrease with increasing heat source separation distance during hybrid welding. Heat source separation distance affects these properties more significantly than the arc current within the range of currents considered. Improved arc stability and higher electrical conductivity of the hybrid welding plasma result from increased heat flux, electron temperatures, electron density, and metal vapor concentrations relative to arc or laser welding.

  8. Modeling of an electric arc transferred on a melted glass bath; Modelisation d`un arc electrique transfere sur un bain de verre

    Energy Technology Data Exchange (ETDEWEB)

    Mehlman, G.; Langlois, A. [SGN, 78 - Saint Quentin en Yvelines (France)

    1997-12-31

    The aim of this study is to propose a methodology allowing the simulation of melting processes involving electromagnetic phenomena. This methodology is based on the use of scientific calculation tools currently used elsewhere. The case considered in this study has been defined in collaboration with Electricite de France (EdF) and concerns more particularly an electric arc vitrification process for wastes. Basic data have been determined in order to obtain results representative of the tests performed by EdF with pilot installations. (J.S.)

  9. Calorimeter probes for measuring high thermal flux. [in electric-arc jet facilities for planetary entry heating simulation

    Science.gov (United States)

    Russell, L. D.

    1979-01-01

    The paper describes expendable, slug-type calorimeter probes developed for measuring high heat-flux levels of 10-30 kW/sq cm in electric-arc jet facilities. The probes are constructed with thin tungsten caps mounted on Teflon bodies; the temperature of the back surface of the tungsten cap is measured, and its rate of change gives the steady-state, absorbed heat flux as the calorimeter probe heats to destruction when inserted into the arc jet. It is concluded that the simple construction of these probes allows them to be expendable and heated to destruction to obtain a measurable temperature slope at high heating rates.

  10. Numerical study on iron particles behaviour injected in an argon plasma from an electric transferred arc

    Energy Technology Data Exchange (ETDEWEB)

    Douce, A.; Flour, I.

    1995-11-01

    In the scope of the Research and Development Project `Control of Plasma/Product Interaction`, the aim of this study is to analyze the behaviour of iron particles injected in an argon plasma flow from an electric transferred arc. It includes particle trajectories and, heat and mass transfer (as the particle undergoes smelting and evaporation), using a 3 dimensional Lagrangian simulation with the numerical code ESTET. The plasma flow is a result of a calculation done using Melodie, a 2 dimensional axisymmetrical software, in the scope of a modelling bath heating with plasma transferred arc. The first step consists of an analysis on the forces applied to a single particle. Simulations show that equation of motion would reduce, finally, to the sum of the drag force and the gravitational effects. In a second step, special attention is given to the effect of steep temperature gradients (across the boundary layer around the particle) on the evaluation of the plasma properties, the drag coefficient, and the heat and mass transfer coefficients. The comparison of several correlations show that the definition of the mean temperature mainly controls the calculation of plasma properties across the boundary layer around the particle.At least, several particle injection conditions are tested on four different sizes particles (50, 100, 150 et 200{mu}m), showing that the 200 {mu}m particle is the only one falling into the bath, without being completely evaporated. However, taking into account the `blow-up effect`, induced by evaporation, leads to a decrease of the heat transfer coefficient which slow down the evaporation, and then modify the conclusion made before. (authors). 18 refs., 41 figs., 5 tabs., 4 appends.

  11. Ionization and electric field properties of auroral arcs during magnetic quiescence

    International Nuclear Information System (INIS)

    Robinson, R.M.; Mende, S.B.

    1990-01-01

    Studies of the morphology of auroral precipitation during times of magnetic quiescence indicate that the polar cap shrinks and becomes distorted into a teardrop or pear-shaped region. On November 16, 1987, incoherent scatter radar and all-sky imaging photometer measurements were made of auroral arcs over Sondre Stromfjord, Greenland. The arcs were generally oriented in a geographic east-west direction which is approximately Sun aligned at a local time just after dusk. Kp was 1, and the interlplanetary magnetic field was northward during the time of observation, so tha the arcs occurred under magnetically quiet conditions. The Sondrestrom radar measurements were used to determine the electron density and plasma drifts associated with the arcs; the all-sky imaging photometer data were used to relate the radar measurements to the arc morphology. Assuming the arcs were produced by precipitating electrons, the height profiles of electron density indicate average energies less than about 2 keV and energy fluxes of 1 erg/(cm 2 s). F region electron densities were high in the polar cap north of the arcs and low within the region of the arcs. The poleward boundary of the arc system was a convection reversal boundary across which plasma exited the polar cap region moving antisunward and then turned sunward (westward). The observed arc-associated convection is consistent with that expected under these geomagnetic conditions. Comparison of these results with the electrodynamic properties of other arcs observed in the afternoon and early evening suggests that there is a system of arcs that delineates the afternoon convection cell. The observed gradient in F region electron density across the arc can be explained in terms of the recombination of ionization drifting in response to the arc-associated convection pattern

  12. Stability of very-high pressure arc discharges against perturbations of the electron temperature

    Energy Technology Data Exchange (ETDEWEB)

    Benilov, M. S. [Departamento de Fisica, Ciencias Exactas e Engenharia, Universidade da Madeira, Largo do Municipio, Funchal 9000 (Portugal); Hechtfischer, U. [Philips Lighting, BU Automotive Lamps, Technology, Philipsstrasse 8, Aachen 52068 (Germany)

    2012-04-01

    We study the stability of the energy balance of the electron gas in very high-pressure plasmas against longitudinal perturbations, using a local dispersion analysis. After deriving a dispersion equation, we apply the model to a very high-pressure (100 bar) xenon plasma and find instability for electron temperatures, T{sub e}, in a window between 2400 K and 5500-7000 K x 10{sup 3} K, depending on the current density (10{sup 6}-10{sup 8} A/m{sup 2}). The instability can be traced back to the Joule heating of the electron gas being a growing function of T{sub e}, which is due to a rising dependence of the electron-atom collision frequency on T{sub e}. We then analyze the T{sub e} range occurring in very high-pressure xenon lamps and conclude that only the near-anode region exhibits T{sub e} sufficiently low for this instability to occur. Indeed, previous experiments have revealed that such lamps develop, under certain conditions, voltage oscillations accompanied by electromagnetic interference, and this instability has been pinned down to the plasma-anode interaction. A relation between the mechanisms of the considered instability and multiple anodic attachments of high-pressure arcs is discussed.

  13. Novel Direct Steelmaking by Combining Microwave, Electric Arc, and Exothermal Heating Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Xiaodi Huang; Dr. J. Y. Hwang

    2005-03-28

    Steel is a basic material broadly used by perhaps every industry and individual. It is critical to our nation's economy and national security. Unfortunately, the American steel industry is losing competitiveness in the world steel production field. There is an urgent need to develop the next generation of steelmaking technology for the American steel industry. Direct steelmaking through the combination of microwave, electric arc, and exothermal heating is a revolutionary change from current steelmaking technology. This technology can produce molten steel directly from a shippable agglomerate, consisting of iron oxide fines, powdered coal, and ground limestone. This technology is projected to eliminate many current intermediate steelmaking steps including coking, pellet sintering, blast furnace (BF) ironmaking, and basic oxygen furnace (BOF) steelmaking. This technology has the potential to (a) save up to 45% of the energy consumed by conventional steelmaking; (b) dramatically reduce the emission of CO{sub 2}, SO{sub 2}, NO{sub x}, VOCs, fine particulates, and air toxics; (c) substantially reduce waste and emission control costs; (d) greatly lower capital cost; and (e) considerably reduce steel production costs. This technology is based on the unique capability of microwaves to rapidly heat steelmaking raw materials to elevated temperature, then rapidly reduce iron oxides to metal by volumetric heating. Microwave heating, augmented with electric arc and exothermal reactions, is capable of producing molten steel. This technology has the components necessary to establish the ''future'' domestic steel industry as a technology leader with a strong economically competitive position in world markets. The project goals were to assess the utilization of a new steelmaking technology for its potential to achieve better overall energy efficiency, minimize pollutants and wastes, lower capital and operating costs, and increase the competitiveness of the

  14. Simulation of convection-stabilized low-current glow and arc discharges in atmospheric-pressure air

    International Nuclear Information System (INIS)

    Naidis, G V

    2007-01-01

    A two-dimensional model of stationary convection-stabilized low-current glow and arc discharge columns in atmospheric-pressure air is developed which accounts for deviation of the plasma state from the local thermodynamic equilibrium (LTE). In addition to equations of energy, continuity and momentum (analogous to those used in LTE arc models), the non-LTE model includes balance equations for plasma species and for the vibrational energy of nitrogen molecules. The kinetic scheme is used which was developed recently for the simulation of low-current wall-stabilized discharges in air. Results of calculation of discharge parameters over a wide current range are presented. It is shown that the non-equilibrium effects are substantial at currents lower than ∼ 100 mA. The calculated plasma parameters agree with available experimental data

  15. Morphology, thermal, electrical and electrochemical stability of nano ...

    Indian Academy of Sciences (India)

    In the present work, an attempt has been made to develop nano aluminium oxide (Al2O3)-filled polyvinyl alcohol (PVA) composite gel electrolytes. Surface morphological studies, thermal behaviour, electrochemical stability and electrical characterization of these composite gel electrolytes have been performed. An increase ...

  16. Morphology, thermal, electrical and electrochemical stability of nano

    Indian Academy of Sciences (India)

    In the present work, an attempt has been made to develop nano aluminium oxide (Al2O3)-filled polyvinyl alcohol (PVA) composite gel electrolytes. Surface morphological studies, thermal behaviour, electrochemical stability and electrical characterization of these composite gel electrolytes have been performed. An increase ...

  17. Microwave treatment of electric arc furnace dust with PVC: dielectric characterization and pyrolysis-leaching.

    Science.gov (United States)

    Al-Harahsheh, Mohammad; Kingman, Sam; Al-Makhadmah, Leema; Hamilton, Ian E

    2014-06-15

    Microwave treatment of electric arc furnace dust (EAFD) with poly(vinyl chloride) (PVC) was studied in this work. A comprehensive characterization of the dust as well as assessing the suitability of using the thermal de-chlorination of the common plastic (PVC) under inert atmosphere was carried out to assess the possibility of Zn and other heavy metals extraction (Pb and Cd) from EAFD. The dielectric and thermal properties of EAFD, PVC and their mixtures were measured. Once combined and heated the metal oxides present in the dust reacted with HCl released from PVC during thermal de-chlorination, forming metal chlorides which were subsequently recovered by leaching with water. It was found that zinc chloride could be almost completely recovered in the leaching stage, with the overall recovery of Zn reaching 97% when the EAFD:PVC ratio was 1:2. The investigation highlighted that franklinite, the most refractory mineral to leaching, was completely destroyed. The leaching residue was found to compose mainly of magnetite and hematite. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Turning waste into valuable resource: potential of electric arc furnace dust as photocatalytic material.

    Science.gov (United States)

    Sapiña, M; Jimenez-Relinque, E; Castellote, M

    2014-10-01

    This paper explores the potential of a hazardous waste of difficult management, electric arc furnace dust (EAFD), as photocatalytic material. Starting from a real waste coming from a Spanish steel factory, chemical, mineralogical, and optical characterizations have been carried out. Direct trials on EAFD and mortar containing this waste have been performed to evaluate its potential as photocatalyst itself and within a cementitious material. The analysis of photocatalytic properties has been done by two different methods: degradation of NO x and degradation of rhodamine (RhB). As a result, it can be said that EAFD exhibited photocatalytic activity for both configurations with UV and visible light, having the mortar enhanced photocatalytic activity for NO x with respect to the EAFD itself. Additionally, in direct trials on the EAFD, it has been able to degrade RhB even in the dark, which has been attributed to transfer of electrons between the adsorbed RhB and the conduction band of some oxides in the dust.

  19. Thermal Analysis on the Pyrolysis of Tetrabromobisphenol A and Electric Arc Furnace Dust Mixtures

    Science.gov (United States)

    Al-Harahsheh, Mohammad; Al-Otoom, Awni; Al-Jarrah, Muhannad; Altarawneh, Mohammednoor; Kingman, Sam

    2018-02-01

    The pyrolysis of Tetrabromobisphenol A (TBBPA) mixed with electric arc furnace dust (EAFD) was studied using thermogravimetric analysis (TGA) and theoretically analyzed using thermodynamic equilibrium calculations. Mixtures of both materials with varying TBBPA loads (1:1 and 1:3) were prepared and pyrolyzed in a nitrogen atmosphere under dynamic heating conditions at heating rates of 5 and 10 °C/min. The mixtures degraded through several steps, including decomposition of TBBPA yielding mainly HBr, bromination of metal oxides, followed by their evaporation in the sequence of CuBr3, ZnBr2, PbBr2, FeBr2, MnBr2, KBr, NaBr, CaBr2, and MgBr2, and finally reduction of the remaining metal oxides by the char formed from decomposition of TBBPA. Thermodynamic calculations suggest the possibility of selective bromination of zinc and lead followed by their evaporation, leaving iron in its oxide form, while the char formed may serve as a reduction agent for iron oxides into metallic iron. However, at higher TBBPA volumes, iron bromide forms, which can also be evaporated at a temperature higher than those of ZnBr2 and PbBr2. Results from this work provide practical insight into selective recovery of valuable metals from EAFD while at the same time recycling the hazardous bromine content in TBBPA.

  20. Development of processes for zircaloy chips recycling by electric arc furnace remelting and powder metallurgy

    International Nuclear Information System (INIS)

    Pereira, Luiz Alberto Tavares

    2014-01-01

    PWR reactors employ, as nuclear fuel, UO 2 pellets with Zircaloy clad. In the fabrication of fuel element parts, machining chips from the alloys are generated. As the Zircaloy chips cannot be discarded as ordinary metallic waste, the recycling of this material is important for the Brazilian Nuclear Policy, which targets the reprocess of Zircaloy residues for economic and environmental aspects. This work presents two methods developed in order to recycle Zircaloy chips. In one of the methods, Zircaloy machining chips were refused using an electric-arc furnace to obtain small laboratory ingots. The second one uses powder metallurgy techniques, where the chips were submitted to hydriding process and the resulting material was milled, isostatically pressed and vacuum sintered. The ingots were heat-treated by vacuum annealing. The microstructures resulting from both processing methods were characterized using optical and scanning electron microscopy. Chemical composition, crystal phases and hardness were also determined. The results showed that the composition of recycled Zircaloy comply with the chemical specifications and presented adequate microstructure for nuclear use. The good results of the powder metallurgy method suggest the possibility of producing small parts, like cladding end-caps, using near net shape sintering. (author)

  1. Preparation of concrete mixtures with electric arc furnace slag and recycled ground glass

    Science.gov (United States)

    Pérez Rojas, Y.; López, E. Vera; López Rodríguez, M.; Díaz Pita, J.

    2017-12-01

    The present work includes the first advances in the development of investigations that seek to include Ground Grinding Glass (GRR) and the Electric Arc Furnace Slag (EAFS) in the production of mixtures of hydraulic concrete mixing them simultaneously, so that it satisfies the specifications techniques to be used in the construction of rigid pavements. Firstly, we cite the tests carried out on the different materials to obtain their physical, chemical and mechanical characterization and determine their compliance, as well as the measurement of certain characteristics that may be somewhat empirical to standardize their control. Technique such as X-Ray Diffraction (XRD), X-ray Fluorescence Spectrometry (XFR) and Scanning Electron Microscopy (SEM) have been used. Once the results of the characterization tests and their correspondence with the Colombian technical standards have been obtained, it has become possible to select the use of the Transparent Recycled Ground Glass (TRGG) as the most suitable for the replacement of the sand in the dosage of new mixtures modified concrete.

  2. Specificity of the tomography implementation in electric arc domain - Validity in medical imaging

    International Nuclear Information System (INIS)

    Benech, Julie

    2008-01-01

    The aim of these works was to implement a new experimental method to characterize 3D thermal plasmas by emission spectroscopy. The method used is based on tomographic technique which is widely used in medical imaging nowadays. However, tomography that we have developed and applied to electric arc is specific as the number of accessible projections angles is strongly limited: 4 projections our case against basically 64 in medical imaging. The particularity of our experimental tomographic system is that measurements are resolved both spectrally and spatially. The spectral resolution is necessary to determine the temperature values from method based on atomic line intensity. The spatial resolution is needed to simultaneously acquire the whole width of the plasma and so to reconstruct a whole cross-section in only one acquisition. One of the principal objective was to realize the experimental system of four-view tomography for thermal plasmas. Thanks to this device, we showed that the characterization of non-axisymmetric plasma is possible and that it enables to reconstruct 3D temperature maps. Finally, our tomographic method is applied with medical imaging data acquired in SPECT (Single Photon Emission Computed Tomography). These tests allowed validating the use of our tomographic reconstruction technique in SPECT, particularly the used iterative algebraic algorithm and the limited-view configuration. (author) [fr

  3. Electric arc spraying for restoration and repair of metallurgical equipment parts

    Directory of Open Access Journals (Sweden)

    В’ячеслав Олександрович Роянов

    2016-07-01

    Full Text Available It has been shown that the electric arc spraying with the use of powder wires can be used to repair and restore parts of metallurgical equipment. The technology of spraying parts by means of the cored wire Steelcored M8TUV; T462MMIN5 and combinations of steel and aluminum wires to restore shaft-gears, shaft-beams, cranes axles for the foundry of the Moldavian Metallurgical Plant has been introduced. The composition of the flux-cored wires MMP-2,3 developed at the Department of Equipment and welding production technology of PSTU that provides the required hardness and adhesion of the coating and the substrate have been shown and the results of the coatings properties studies have been published. Studies have shown matching properties of the coatings to be used for details of the metallurgical equipment working under difficult conditions, including the rolls of rolling mills. Cored wire was used for pilot plating of the rolls surface of the skin-rolling stand at the cold-rolling mill at Illich Steel and Iron Works, Mariupol. Residual coating thickness ranged from 15 to 25 microns. Strip sized 0,9 × 1025 mm has been rolled, the squeezing is equal to 0,8...1,0%.

  4. Rheological Characterization of Warm-Modified Asphalt Mastics Containing Electric Arc Furnace Steel Slags

    Directory of Open Access Journals (Sweden)

    M. Pasetto

    2016-01-01

    Full Text Available The environmental sustainability of road materials and technologies plays a key role in pavement engineering. In this sense, the use of Warm Mix Asphalt (WMA, that is, a modified asphalt concrete that can be produced and applied at lower temperature, is considered an effective solution leading to environmental and operational benefits. The environmental sustainability of WMA can be further enhanced with the inclusion of steel slag in partial substitution of natural aggregates. Nevertheless, such innovative material applied at lower temperatures containing warm additives and steel slag should be able to guarantee at least the same performance of traditional hot mix asphalts, thus assuring acceptable mechanical properties and durability. Therefore, the purpose of this study is to investigate the rheological behaviour of bituminous mastics obtained combining a warm-modified binder and a filler (material passing to 0.063 mm coming from electric arc furnace steel slag. To evaluate the influence of both warm additive and steel slag, a plain binder and limestone filler were also used for comparison purposes. Complex modulus and permanent deformation resistance of bitumens and mastics were assessed using a dynamic shear rheometer. Experimental results showed that steel slag warm mastics assure enhanced performance demonstrating promising applicability.

  5. Emissions of polyciclic aromatic hydrocarbons and polyciclic carbonyl biphenils from electric arc furnaces

    Directory of Open Access Journals (Sweden)

    P. Gomes, J. F.

    2008-06-01

    Full Text Available This paper describes work done in order to determine the emissions of highly toxic organic micropollutants from electric arc furnaces used in the production of carbon steel from scrap. The study will be allowing to derive relationships between the levels of airborne micropollutants and the operational parameters of the production process so that an abatement of pollution could be achieved. By using the European standard method CEN 1948 for dioxin like compounds sampling and measurement, it was possible to determine the characteristic fingerprint of micropollutants such as polyciclic aromatic hydrocarbons (PAHs and polycyclic carbonyl biphenils (PCBs emitted by this particular stationary source.

    Este artículo contiene resultados del trabajo ejecutado para estudiar la determinación de las emisiones de los micropolutantes orgánicos muy tóxicos que se emiten por los hornos eléctricos de arco utilizados en la producción de acero. Este estudio inicial va a permitir relacionar las concentraciones de polutantes emitidos a la atmósfera con las condiciones de operación del horno eléctrico de arco. Utilizando el método normalizado CEN 1948 para captación y análisis de muestras de compuestos análogos a las dioxinas ha sido posible determinar el perfil característico de los micropolutantes tales como PAHs y PCBs emitidos por esta fuente.

  6. Foaming in Electric Arc Furnace—Part II: Foaming Visualization and Comparison with Plant Trials

    Science.gov (United States)

    Chychko, Andrei; Teng, Lidong; Seetharaman, Seshadri

    2012-10-01

    The kinetics of slag foaming by limestone particles was studied at 1773 K (1500 °C) with the aid of an X-ray imaging system. Two models were implemented to describe the decrease in foam height with the time on the basis of the lowering of the average temperature and CaO shell formation during decomposition reaction. The energy impact of carbonate additions was studied on an industrial scale in a 100-ton electric arc furnace (EAF). It was found that, in the case of the addition of carbonates after the scrap is completely molten, the heat effects for limestone and dolomite (2255 and 2264 kJ/kg, respectively) were only 70 pct from theoretical values. Comparing these values with similar additions during the scrap melting stage shows that the energy requirements in the case of carbonate additions to steel bath are much smaller. It was found from the trial heats with dolomite addition to the steel bath that the partial substitution of lime by raw dolomite can be made without an increase in energy consumption.

  7. On the electrodynamic explanation of the retrograde motion of the electric arc

    International Nuclear Information System (INIS)

    Hong, J.S.; Allen, J.E.

    1992-01-01

    The retrograde motion of the cathode spot in a transverse magnetic field is one of the more intriguing phenomena of the electric arc. Although the phenomenon has been known for nearly ninety years since its discovery by Stark and has stimulated numerous investigations which result in many models giving explanation from different points of view, there is still no theory that can account both qualitatively and quantitatively for all the observations. Most of the explanations of the retrograde motion involve the study of cathode processes to give the preferential formation of new cathode spots along the retrograde direction. One line of explanation, which is rather different from the others, is based on electrodynamics. In this approach the retrograde motion is treated as an electrodynamic event. The present paper develops the theory suggested by Robson and von Engel. A more complete model is proposed and studied in detail by means of electromagnetic field theory. The results obtained not only show that the retrograde motion can be explained by the electrodynamics, but also confirm that the average current density on the cathode spot must be around the order of 10 12 A/m 2 . Recent studies of spot current density have shown values of this order. (author) 22 refs., 4 figs., 1 tab

  8. Recovery of Zn from acid mine water and electric arc furnace dust in an integrated process.

    Science.gov (United States)

    Carranza, Francisco; Romero, Rafael; Mazuelos, Alfonso; Iglesias, Nieves

    2016-01-01

    In this paper, the purification of acid mine water and the treatment of electric arc furnace dust (EAFD) are integrated into one process with the aim of recovering the Zn content of both effluent and waste. Zinc recovery can reduce the cost of their environmental management: purified acid mine water is discharged after removing all metals; EAFD ceases to be hazardous waste; and Zn is valorised. The process consists of the recovery of Zn as zinc oxide and its purification into commercial products. First, EAFD is leached with acid water and the dissolved metals are selectively precipitated as hydroxides. After EADF leaching, ferrous iron is bio-oxidized and Fe and Al are then precipitated; in the following stage, Cu, Ni, Co and Cd are cemented and finally Zn is precipitated as ZnO. In order to purify water that finally is discharged to a river, lime is used as the neutralizing agent, which results in a precipitate of mainly gypsum, MnO, and ZnO. From the impure zinc oxide produced, various alternatives for the attainment of commercial products, such as basic zinc carbonate and electrolytic zinc, are studied in this work. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Simultaneous obtention of multicomponent ferroalloy and slag from black sands for the development of electrical arc welding consumables

    International Nuclear Information System (INIS)

    Cruz-Crespo, A.; Gomez-Rodriguez, L.; Garcia-Sanchez, L. L.; Quintana-Puchol, R.; Cerpa-Naranjo, A.; Cores-Sanchez, A.

    2004-01-01

    In this paper, chemical and mineralogical characterizations of the black sands of the Mejias placer of Sagua de Tanamo (the most important beach littoral placer of the northwest of oriental Cuba) are exposed. Starting from these characterizations a calculation strategy is developed for the making of the metallurgical load that allows to obtain simultaneously, when processed by carbothermic reduction in an electrical arc furnace, a multicomponent ferroalloy and a useful slag for the making of electric arch welding consumables. The powder of the obtained slag is agglomerated with liquid glass. The resulting pellets, due to their behavior on the submerged arc welding (SAW) present technological and metallurgical properties that correspond with the requirements of an agglomerated flux matrix. The chemical composition of the multicomponent ferroalloy is constituted by metallic elements of high metallurgical and alloyed values (V, Cr, Mo, Ti, Nb). It is appropriate for the formulation of consumables for manual welding (SMAW) and SAW, as well. (Author) 15 refs

  10. THE STABILITY MONITORING OF THE MANUFACTURING PROCESS OF ELECTRICAL INSULATING SYSTEMS OF TRACTION ELECTRIC MACHINES

    Directory of Open Access Journals (Sweden)

    G. V. Bezprozvannych

    2017-12-01

    Full Text Available Introduction. Electrical insulation systems make up about 0.03 % of the traction electric machines (TEM mass, but they are of exceptional importance and affect the design capabilities and manufacturing techniques of electric machines, ultimately - on their specific weight and overall dimensions, on the reliability and durability of the TEM. Purpose. The monitoring of the stability of the manufacturing process of electrical insulating systems of the TEM based on the insulation resistance measurements. Methodology. The analysis of the manufacturing process is carried out for three versions of the case of insulation of the magnetic system of the DC traction electric motor. Practical value. Construction and analysis of special graphs (charts of individual values and cumulative sums of insulation resistance, sliding range MR allow to find out whether the technological process of manufacturing electric insulating systems of traction electric machines is in a statistically controllable state.

  11. Electricity Market Stochastic Dynamic Model and Its Mean Stability Analysis

    Directory of Open Access Journals (Sweden)

    Zhanhui Lu

    2014-01-01

    Full Text Available Based on the deterministic dynamic model of electricity market proposed by Alvarado, a stochastic electricity market model, considering the random nature of demand sides, is presented in this paper on the assumption that generator cost function and consumer utility function are quadratic functions. The stochastic electricity market model is a generalization of the deterministic dynamic model. Using the theory of stochastic differential equations, stochastic process theory, and eigenvalue techniques, the determining conditions of the mean stability for this electricity market model under small Gauss type random excitation are provided and testified theoretically. That is, if the demand elasticity of suppliers is nonnegative and the demand elasticity of consumers is negative, then the stochastic electricity market model is mean stable. It implies that the stability can be judged directly by initial data without any computation. Taking deterministic electricity market data combined with small Gauss type random excitation as numerical samples to interpret random phenomena from a statistical perspective, the results indicate the conclusions above are correct, valid, and practical.

  12. A Laboratory Study of the Treatability of Synthetic Stormwater Under Varying Conditions Using Electric Arc Furnace Steel Slag

    Directory of Open Access Journals (Sweden)

    Nnaemeka C. Okochi

    2012-03-01

    Full Text Available The investigation of electric arc furnace (EAF steel slag as a viable add-on technology to existing stormwater systems for the removal of dissolved phosphorus (P was extended to explore the effects of varying environmental and treatment system conditions. Parameters such as stormwater composition, P concentration, metal concentration, pH, temperature, slag mass and slag particle size were varied. Observations relating to the method of P removal via EAF slag were also carefully considered to explain removal mechanisms involved. Results demonstrated that, although physisorption contributed to P reduction, it was not the key P removal mechanism. Instead, precipitation was observed to be a key removal pathway as evidenced by the correlation between the loss of iron (Fe from slag and the amount of P removed from solution. The reduced removal of P by slag in a copper-dominant stormwater solution was attributed to the formation of a stable complex formed by the interaction of copper with the slag via the ion-exchange surface model. The stability of this complex inhibits the loss of Fe from the EAF slag and, consequently, P removal by means of precipitation. In terms of the effect of changing environmental and treatment system conditions on the P removal process, stormwater composition, P concentration, metal concentration, pH, temperature, slag mass and slag particle size were found to significantly influence the effectiveness of EAF slag in removing P from a given stormwater system. It was also established that a number of combinations of these factors influence P uptake differently.

  13. Knowledge on the Health Effects of Welding Smoke, Use of PPE Among Electric-Arc Welders in Ilorin South, North Central Nigeria

    OpenAIRE

    Kayode Rasaq ADEWOYE; Ademola Olugbenga AWOYEMI; Demilade Olusola IBIRONGBE; Oluwole Adeyemi BABATUNDE; Tayo IBRAHIM

    2013-01-01

    INTRODUCTION: Electric arc welding and oxy-fuel gas welding are the commonest welding technologies used in small scale industries in Nigeria. Electric arc welders are exposed to serious health hazards like exposure to welding smoke. Health effects of such exposure include metal fume fever, and increased risk of chronic diseases and cancers. Exposure to welding smoke can be minimized by use of PPE. The aim of the study is to determine the knowledge of welders on health implication of welding s...

  14. Handbook of electrical power system dynamics modeling, stability, and control

    CERN Document Server

    Eremia, Mircea

    2013-01-01

    Complete guidance for understanding electrical power system dynamics and blackouts This handbook offers a comprehensive and up-to-date treatment of power system dynamics. Addressing the full range of topics, from the fundamentals to the latest technologies in modeling, stability, and control, Handbook of Electrical Power System Dynamics provides engineers with hands-on guidance for understanding the phenomena leading to blackouts so they can design the most appropriate solutions for a cost-effective and reliable operation. Focusing on system dynamics, the book details

  15. Sensoring Fusion Data from the Optic and Acoustic Emissions of Electric Arcs in the GMAW-S Process for Welding Quality Assessment

    Directory of Open Access Journals (Sweden)

    Eber Huanca Cayo

    2012-05-01

    Full Text Available The present study shows the relationship between welding quality and optical-acoustic emissions from electric arcs, during welding runs, in the GMAW-S process. Bead on plate welding tests was carried out with pre-set parameters chosen from manufacturing standards. During the welding runs interferences were induced on the welding path using paint, grease or gas faults. In each welding run arc voltage, welding current, infrared and acoustic emission values were acquired and parameters such as arc power, acoustic peaks rate and infrared radiation rate computed. Data fusion algorithms were developed by assessing known welding quality parameters from arc emissions. These algorithms have showed better responses when they are based on more than just one sensor. Finally, it was concluded that there is a close relation between arc emissions and quality in welding and it can be measured from arc emissions sensing and data fusion algorithms.

  16. Sensoring Fusion Data from the Optic and Acoustic Emissions of Electric Arcs in the GMAW-S Process for Welding Quality Assessment

    Science.gov (United States)

    Alfaro, Sadek Crisóstomo Absi; Cayo, Eber Huanca

    2012-01-01

    The present study shows the relationship between welding quality and optical-acoustic emissions from electric arcs, during welding runs, in the GMAW-S process. Bead on plate welding tests was carried out with pre-set parameters chosen from manufacturing standards. During the welding runs interferences were induced on the welding path using paint, grease or gas faults. In each welding run arc voltage, welding current, infrared and acoustic emission values were acquired and parameters such as arc power, acoustic peaks rate and infrared radiation rate computed. Data fusion algorithms were developed by assessing known welding quality parameters from arc emissions. These algorithms have showed better responses when they are based on more than just one sensor. Finally, it was concluded that there is a close relation between arc emissions and quality in welding and it can be measured from arc emissions sensing and data fusion algorithms. PMID:22969330

  17. Stark broadening of potassium ns-4p and nd-4p lines in a wall-stabilized arc

    International Nuclear Information System (INIS)

    Hohimer, J.P.

    1984-01-01

    Stark-width measurements are reported for lines in the ns-4p (n = 7--10) and nd-4p (n = 5--8) series in neutral potassium (K I). These measurements were made by observing the end-on emission from a low pressure (20 Torr) potassium-argon wall-stabilized arc source. The on-axis electron density and temperature in the 20-A arc were (2.0 +- 0.2) x 10 15 cm -3 and 2955 +- 100 K, respectively. The experimentally determined Stark widths were compared with the theoretical values calculated by Griem. The measured Stark widths agreed with theory to within 30% for lines in the ns-4p series; while the measured Stark widths of the nd-4p series lines were only one-third of the theoretical values

  18. The electric power engineering handbook power system stability and control

    CERN Document Server

    Grisby, Leonard L

    2012-01-01

    With contributions from worldwide leaders in the field, Power System Stability and Control, Third Edition (part of the five-volume set, The Electric Power Engineering Handbook) updates coverage of recent developments and rapid technological growth in essential aspects of power systems. Edited by L.L. Grigsby, a respected and accomplished authority in power engineering, and section editors Miroslav Begovic, Prabha Kundur, and Bruce Wollenberg, this reference presents substantially new and revised content. Topics covered include: * Power System Protection * Power System Dynamics and Stability *

  19. Preliminary Results from Electric Arc Furnace Off-Gas Enthalpy Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Nimbalkar, Sachin U [ORNL; Thekdi, Arvind [E3M Inc; Keiser, James R [ORNL; Storey, John Morse [ORNL

    2015-01-01

    This article describes electric arc furnace (EAF) off-gas enthalpy models developed at Oak Ridge National Laboratory (ORNL) to calculate overall heat availability (sensible and chemical enthalpy) and recoverable heat values (steam or power generation potential) for existing EAF operations and to test ORNL s new EAF waste heat recovery (WHR) concepts. ORNL s new EAF WHR concepts are: Regenerative Drop-out Box System and Fluidized Bed System. The two EAF off-gas enthalpy models described in this paper are: 1.Overall Waste Heat Recovery Model that calculates total heat availability in off-gases of existing EAF operations 2.Regenerative Drop-out Box System Model in which hot EAF off-gases alternately pass through one of two refractory heat sinks that store heat and then transfer it to another gaseous medium These models calculate the sensible and chemical enthalpy of EAF off-gases based on the off-gas chemical composition, temperature, and mass flow rate during tap to tap time, and variations in those parameters in terms of actual values over time. The models provide heat transfer analysis for the aforementioned concepts to confirm the overall system and major component sizing (preliminary) to assess the practicality of the systems. Real-time EAF off-gas composition (e.g., CO, CO2, H2, and H2O), volume flow, and temperature data from one EAF operation was used to test the validity and accuracy of the modeling work. The EAF off-gas data was used to calculate the sensible and chemical enthalpy of the EAF off-gases to generate steam and power. The article provides detailed results from the modeling work that are important to the success of ORNL s EAF WHR project. The EAF WHR project aims to develop and test new concepts and materials that allow cost-effective recovery of sensible and chemical heat from high-temperature gases discharged from EAFs.

  20. Influence of direct reduced iron on the energy balance of the electric arc furnace in steel industry

    International Nuclear Information System (INIS)

    Kirschen, Marcus; Badr, Karim; Pfeifer, Herbert

    2011-01-01

    A model of the EAF energy efficiency was developed based on a closed mass and energy balance of the EAF melting process. This model was applied to industrial EAFs in steel industry charged with scrap or with mixes of scrap and DRI. Complex mass and energy conversion in the EAF was simplified with the introduction of mass and energy conversion efficiencies for the conversion of oxygen and the energy conversion of electrical energy in the electric arcs, chemical energy from the oxidation reactions in the melt and energy from the combustion of burner gas. It turned out that close agreement with observed process parameters from 16 EAFs is obtained by slight variations of the efficiency values. Especially the sensitivity of the steel temperature from the energy conversion efficiency of the electric arc energy indicates the importance of efficient foaming slag operation in EAF steel making. Characteristics and process parameters of DRI charged EAFs are discussed. Model results for a series of case studies illustrate the correlations between DRI chemical composition, DRI portion, oxygen consumption, etc. with electrical energy demand in order to indentify cost-effective EAF process conditions. -- Highlights: → Energy demand and carbon dioxide emission figures of EAF steelmaking processes based on steel scrap and DRI. → Complete energy balance of the EAF process using various input materials. → Application of the model to industrial EAF in steel industry in 4 case studies and discussion of model results. → Comparison with other models, critical discussion.

  1. Recycling of Malaysia's electric arc furnace (EAF) slag waste into heavy-duty green ceramic tile.

    Science.gov (United States)

    Teo, Pao-Ter; Anasyida, Abu Seman; Basu, Projjal; Nurulakmal, Mohd Sharif

    2014-12-01

    Recently, various solid wastes from industry such as glass waste, fly ash, sewage sludge and slag have been recycled into various value-added products such as ceramic tile. The conventional solutions of dumping the wastes in landfills or incineration, including in Malaysia are getting obsolete as the annual huge amount of the solid wastes would boost-up disposal cost and may cause permanent damage to the flora and fauna. This recent waste recycling approach is much better and greener as it can resolve problems associated with over-limit storage of industrial wastes and reduce exploration of natural resources for ceramic tile to continuously sustain the nature. Therefore, in this project, an attempt was made to recycle electric arc furnace (EAF) slag waste, obtained from Malaysia's steel making industry, into ceramic tile via conventional powder compaction method. The research work was divided into two stages. The first stage was to evaluate the suitability of EAF slag in ceramic tile by varying weight percentage of EAF slag (40 wt.%, 50 wt.% and 60 wt.%) and ball clay (40 wt.%, 50 wt.% and 60 wt.%), with no addition of silica and potash feldspar. In the second stage, the weight percentage of EAF slag was fixed at 40 wt.% and the percentage of ball clay (30 wt.% and 40 wt.%), feldspar (10 wt.% and 20 wt.%) and silica (10 wt.% and 20 wt.%) added was varied accordingly. Results obtained show that as weight percentage of EAF slag increased up to 60 wt.%, the percentage of apparent porosity and water absorption also rose, with a reduction in tile flexural strength and increased porosity. On the other hand, limiting the weight percentage of EAF slag to 40 wt.% while increasing the weight percentage of ball clay led to a higher total percentage of anorthite and wollastonite minerals, resulting in higher flexural strength. It was found that introduction of silica and feldspar further improved the flexural strength due to optimization of densification process. The highest

  2. Study of the instability of black slags from electric arc furnace steel industry

    Directory of Open Access Journals (Sweden)

    Frías, M.

    2002-09-01

    Full Text Available In Spain, the steel manufacture produces important quantities of by-products, representing between 15 and 20 % of total steel production. Most by-products are deposited on open air spaces causing serious economical and environmental problems, internationally, different recycling wais are studied, being the main alternative for these by-products as recycled aggregate. The possibility of recycling these by-products in construction sector depends on its possible volume instability because of the presence of some undesirable compounds. In current paper, two different black slags from electric arc furnace steel industry were chemically characterized, paying attention to some well-known compounds by theirs expansion effects, such as: free CaO, free MgO, chlorides and sulphates. The analytical results carried out in the current research detected the presence of insignificant or null amounts of harmful compounds. Therefore, they should not have any negative incidence on phenomena of volume instability.

    En España la fabricación de acero produce grandes cantidades de residuos industriales, las cuales representan entre el 15-20 % de la producción total de acero, en su mayor parte se depositan en vertederos, causando serios problemas económicos y medioambientales a todos los sectores implicados. A nivel internacional, se están estudiando diferentes vías de reutilización, siendo su uso principal como árido de reciclado. La posibilidad de reutilizar estos subproductos industriales en el sector de la construcción se basa en su posible inestabilidad volumétrica, debido a la presencia de ciertos compuestos no deseados. En este trabajo se caracterizan químicamente 2 escorias negras de horno de arco eléctrico con diferente procedencia y se cuantifican algunos de los principales compuestos conocidos por sus efectos expansivos, como: cal libre, magnesia libre, cloruros y sulfatos. Los resultados analíticos de estas dos escorias negras muestran

  3. Approach to modeling of the fast energy discharge in cryogenic systems in the form of an electric arc

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    Superconducting magnets are supplied with a few kA of electric current and can store a large amount of energy. Therefore, cryogenic systems which are comprised of such magnets are subject to the risk of fast energy discharge from the magnets themselves in the form of an electric arc. The arcing can be a result of failure in the insulation of an electric circuit or in the connection between the magnet and its current lead. During the discharge, energy can be partially dissipated into the cryogen and partially into the cryogenic system metallic structure. The part of the energy that is transferred to the metallic structure will strongly heat up the metal surface, which can lead to material burning. In this case, the cryogen will flow through the perforation to the insulation vacuum space, which can trigger a rapid increase in pressure in the vacuum enclosure. However, the discharged energy that has been stored in the cryogen also causes a rapid increase in cryogenic pressure. Hence, the proper estimation of the...

  4. A glucose concentration and temperature sensor based on long period fiber gratings induced by electric-arc discharge

    Science.gov (United States)

    Du, Chao; Wang, Qi

    2017-10-01

    As one of the key parameters in biological and chemical reactions, glucose concentration objectively reflects the characteristics of reactions, so the real-time monitoring of glucose concentration is important in the field of biochemical. Meanwhile, the influence from temperature should be considered. The fiber sensors have been studied extensively for decades due to the advantages of small size, immunity to electromagnetic interference and high sensitivity, which are suitable for the application of biochemical sensing. A long period fiber grating (LPFG) sensor induced by electric-arc discharge has been fabricated and demonstrated for simultaneous measurement of glucose concentration and temperature. The proposed sensor was fabricated by inscribing a sing mode fiber (SMF) with periodic electric-arc discharge technology. During the fabrication process, the electric-arc discharge technology was produced by a commercial fusion splicer, and the period of inscribed LPFG was determined by the movement of translation stages. A serials of periodic geometrical deformations would be formed in SMF after the fabrication, and the discharge intensity and discharge time can be adjusted though the fusion splicer settings screen. The core mode can be coupled into the cladding modes at certain wavelength when they satisfy the phase-matching conditions, and there will be several resonance dips in the transmission spectrum in LPFG. The resonance dips formed by the coupling between cladding modes and core mode have different sensitivity responses, so the simultaneous measurement for multi-parameter can be realized by monitoring the wavelength shifts of the resonance dips. Compared with the LPFG based on conventional SMF, the glucose concentration sensitivity has been obviously enhanced by etching the cladding with hydrofluoric acid solution. Based on the independent measured results, a dual-parameter measurement matrix has been built for signal demodulation. Because of the easy

  5. Application of Electric-Arc Pulsed Mode for Obtaining Surfacings of Fe–Mo–Cr–Ti–Ni–Cu–Al-System

    Science.gov (United States)

    Knyaz’kov, Anatoly F.; Ditenberg, Ivan A.; Gavrilin, Aleksey N.; Grinyaev, Konstantin V.; Knyaz’kov, Sergey A.; Smirnov, Ivan V.

    2017-10-01

    Method of electric-arc melting with nonconsumable electrode in a protective argon atmosphere with using a pulsed mode was used to show possibility in principle of obtaining multi-component metallic surfacing of Fe–Mo–Cr–Ti–Ni–Cu–Al system on uncooled steel substrate. Features of structure and elemental composition were studied using scanning electron microscopy methods. Component intermixing of the surfacing is observed. Surfacing microhardness is 5 times greater than that of the substrate. «Surfacing-substrate» boundary has high adhesion strength.

  6. Study of coatings from refractory carbide powders on some steel rods prepared by using equipment with a rotating electric arc

    Energy Technology Data Exchange (ETDEWEB)

    Stubicar, M.; Stubicar, N. (Faculty of Science, Univ. of Zagreb (Yugoslavia)); Knezevic, D.; Lukacevic, J. (Engineering Inst. and Faculty of Engineering, Slavonski Brod (Yugoslavia)); Dukic, P. (Jugoturbina Inst., Zagreb (Yugoslavia)); Dmitrovic, R. (Inst. of Metallurgy, Sisak (Yugoslavia)); Subic, J. (Sintal Factory, Zagreb (Yugoslavia))

    1992-05-20

    A successful attempt has been made to use recently developed equipment, which can produce a rotating electric arc, in the preparation of coatings made from refractory carbide powders on certain types of steel. Although some weak points were observed in the applied procedure of coating steel rods, it is still worthwhile to continue investigations in order to improve our coating technique and thus to obtain coating materials with improved properties in comparison with uncoated materials. In particular, it should be noted that this simple method of coating is applicable even to items of very large dimensions. (orig.).

  7. PROPERTIES OF ARC DISCHARGE WITH HYBRID STABILI-ZATION: IMPACT OF DIFFERENT PHYSICAL AND NUMERICAL ASSUMPTIONS

    Czech Academy of Sciences Publication Activity Database

    Jeništa, Jiří; Bartlová, M.; Aubrecht, V.

    2006-01-01

    Roč. 10, č. 4 (2006), s. 501-514 ISSN 1093-3611. [High Technology Plasma Processes (HTPP 9). St. Petersburg, 27.5.2006-4.6.2006] R&D Projects: GA ČR GA202/05/0669 Institutional research plan: CEZ:AV0Z20430508 Keywords : arc * hybrid (water) discharge * partial characteristics * upwind * grid Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.343, year: 2006

  8. Influences on ARC Stability in Welding of Aluminum Pin-Structures

    Science.gov (United States)

    Wittwer, Lukas; Jank, Nasrin; Bećirović, Almedin; Waldhör, Andreas; Enzinger, Norbert

    Pin structures offer an innovative way of joining dissimilar materials such as metals and plastics based on an additional geometric link. Therefore pins are placed on a metal sheet substrate by use of a special arc welding technique called cold metal transfer (CMT), developed by Fronius International. The key element of the CMT process is moving the wire back and forth during the welding process. This controlled movement combined with proper welding parameters allows a defined shaping of the pin.

  9. Finite element modelling of electric currents in AC submerged arc furnaces

    CSIR Research Space (South Africa)

    Mc Dougall, I

    2007-01-01

    Full Text Available Finite element models were generated of two submerged arc furnaces of different geometries. A 48MW circular furnace and a 68MW 6-in-line rectangular furnace were studied. The electrodes, raw material, slag and molten metal were included in the model...

  10. Circular arc fuel plate stability experiments and analyses for the advanced neutron source

    International Nuclear Information System (INIS)

    Swinson, W.F.; Battiste, R.L.; Yahr, G.T.

    1995-08-01

    The thin fuel plates planned for the Advanced Neutron Source are to be cooled by forcing heavy water at high velocity, 25 m/s, through thin cooling channels on each side of each plate. Because the potential for structural failure of the plates is a design concern, considerable effort has been expended in assessing this potential. As part of this effort, experimental flow tests and analyses to evaluate the structural response of circular arc plates have been conducted, and the results are given in this report

  11. Effect of electric arc cutting procedures on the properties of processed metal surface

    International Nuclear Information System (INIS)

    Gutman, L.M.; Novikova, D.P.; Struina, T.A.

    1980-01-01

    Presented are the data of comparative studies of the cutting surface, made by the electrodes of the ANR-2 type and by the coal electrode by the method of air-arc cutting. Absence of carbonization of cutting surface, minimum structural changes in metal and a considerably high productivity permit to recommend the ANR-2 and ANR-2M electrodes for separation metal cutting, weld root and defect area cut without further stripping by the grinding stone

  12. Amygdala electrical stimulation inducing spatial memory recovery produces an increase of hippocampal bdnf and arc gene expression.

    Science.gov (United States)

    Mercerón-Martínez, D; Almaguer-Melian, W; Alberti-Amador, E; Estupiñán, B; Fernández, I; Bergado, J A

    2016-06-01

    Amygdala seems to promote the consolidation of plastic modification in different brain areas and these long-term brain changes require a rapid de novo RNA and protein synthesis. We have previously shown that basolateral amygdala electrical stimulation produces a partial recovery of spatial memory in fimbria-fornix lesioned animals and it is also able to increase the BDNF protein content in the hippocampus. The emerging question is whether these increased BDNF protein content arises from previously synthesized RNA or from de novo RNA expression. Now we address the question if amygdala electrical stimulation 15min after daily water maze training produces a rapid de novo RNA synthesis in the hippocampus, a critical brain area for spatial memory recovery in fimbria-fornix lesioned animals. In addition, we also study RNA arc expression, a gene which is essential for memory and neural plasticity processes. To this purpose, we study amygdala stimulation effects on the expression of plasticity related-early-genes bdnf and arc in the hippocampus of fimbria-fornix lesioned animals trained in a water-maze for 4days. We also checked on the expression of both genes in non-lesioned, untrained animals (acute condition) at 0.5, 1, 2 and 24h after basolateral amygdala electrical stimulation. Our data from trained animals confirm that daily amygdala electrical stimulation 15min after water maze training produces a partial memory recovery and that is coupled to an increase of bdnf and arc genes expression in the hippocampus. Additionally, the acute study shows that a single session of amygdala stimulation induces a transient increase of both genes (peaking at 30min). These results confirm the memory improving effect of amygdala stimulation in fimbria-fornix-lesioned animals and sustain the assumption that the memory improving effect is mediated by newly synthetized BDNF acting on a memory relevant structure like the hippocampus. The increased amount of BDNF within the hippocampus

  13. Evaluation of SF6-alternative gas C5-PFK based on arc extinguishing performance and electric strength

    Science.gov (United States)

    Wu, Yi; Wang, Chunlin; Sun, Hao; Rong, Mingzhe; Murphy, Anthony Bruce; Li, Tianwei; Zhong, Jianying; Chen, Zhexin; Yang, Fei; Niu, Chunpin

    2017-09-01

    C5-PFK (C5-perfluoroketone, C5F10O) is under wide consideration as an environmentally-friendly alternative gas to SF6 in high-voltage applications, because of its superior insulation performance. The aim of this work is to study theoretically the arc extinguishing performance and electric strength of C5-PFK. The arc extinguishing performance of C5-PFK was evaluated by analyzing and comparing the thermophysical properties of C5-PFK, SF6, CF4, CO2 and N2 plasmas. It was difficult to obtain the species formed in C5-PFK plasmas because of the complex C5-PFK molecular decomposition process. In this work, the decomposition process of C5-PFK and the related species were analyzed by the bond energy analysis method. For the species for which parameters such as the partition function and the enthalpy of formation were not available, computational chemistry methods were used to obtain the required data. The collision integrals were calculated using the phenomenological potential model. Using these results, the local thermodynamic equilibrium composition at temperatures from 300 to 30 000 K at 1-10 atm of pure C5-PFK was calculated by the method of minimization of the Gibbs free energy, and the corresponding transport coefficients were calculated by Chapman-Enskog method. Through the comparison of the thermophysical properties, it was found that C5-PFK had similar characteristics to SF6, with large peaks in specific heat below 4500 K, indicating potentially good thermal interruption capability. However, the specific heat peak at 7000 K corresponding to CO decomposition may detract from the thermal interruption capability. Specific heat peaks at higher temperatures are associated with the breaking of double or triple bonds, and should be avoided if possible in the new alternative gases. The electric strength of C5-PFK was assessed using the molecular electrostatic potential, which can be accurately calculated or measured, and gives strong insights into important

  14. Developments of electrical joints for aluminum-stabilized superconducting cables

    CERN Document Server

    Curé, B

    1999-01-01

    Electrical joints for the aluminum-stabilized conductors of the LHC experiment magnets have been studied. Two techniques have been tested: electron beam welding and MIG welding. The joint resistance was measured as a function of the magnetic field on ring shaped samples using the MA.RI.S.A. test facility, wherein current is induced in the test conductor by a varying magnetic field. The resistance is obtained by measuring either the voltage drop or the decay time. Calculation and finite-element simulation have been performed in order to separate the effect of both the copper-aluminum contact resistivity and the aluminum resistivity from the effect due to the joint technique (joint configuration, resistivity of the filler material, increasing of aluminum resistivity in the welding zone). The copper-aluminum contact resistivity and the current transfer length were obtained by measurements of the joint resistance of butt welded samples. (2 refs).

  15. Stabilization and destabilization effects of the electric field on stochastic precipitate pattern

    NARCIS (Netherlands)

    Lagzi, István; Izsak, F.

    2004-01-01

    Stabilization and destabilization effects of an applied electric field on the Liesegang pattern formation in low concentration gradient were studied with numerical model simulations. In the absence of an electric field pattern formation exhibits increasingly stochastic behaviour as the initial

  16. Calculation of t8/5 by response surface methodology for electric arc welding applications

    Directory of Open Access Journals (Sweden)

    Meseguer-Valdenebro José Luis

    2014-01-01

    Full Text Available One of the greatest difficulties traditionally found in stainless steel constructions has been the execution of welding parts in them. At the present time, the available technology allows us to use arc welding processes for that application without any disadvantage. Response surface methodology is used to optimise a process in which the variables that take part in it are not related to each other by a mathematical law. Therefore, an empiric model must be formulated. With this methodology the optimisation of one selected variable may be done. In this work, the cooling time that takes place from 800 to 500ºC, t8/5, after TIG welding operation, is modelled by the response surface method. The arc power, the welding velocity and the thermal efficiency factor are considered as the variables that have influence on the t8/5 value. Different cooling times,t8/5, for different combinations of values for the variables are previously determined by a numerical method. The input values for the variables have been experimentally established. The results indicate that response surface methodology may be considered as a valid technique for these purposes.

  17. Where Diffusion of Clean Technologies and Barriers to Innovation Clash: Application to the Global Diffusion of the Electrical Arc Furnace

    Directory of Open Access Journals (Sweden)

    José Antonio Moya

    2017-01-01

    Full Text Available This paper analyses the role of barriers preventing the worldwide take-up of a clean technology: the electrical arc furnace. It also identifies which barriers affect a parameter that summarises the combined effect of all of them. The first step, determination of the combined effect of the barriers, is carried out using a novel approach to model the diffusion of innovations. This new approach is composed only by terms that account for the driver of innovations and the parameter that summarises the effect of barriers. The objective quantification of the effect of barriers in the diffusion of innovations opens up new opportunities for designing policies to overcome the barriers identified as the most relevant, for identifying the effect of existing policies, for relating innovation indicators with those barriers or for better incorporating the effect of barriers in bottom-up models that forecast the technological evolution of the economy.

  18. Experimental evaluation of high performance base course and road base asphalt concrete with electric arc furnace steel slags.

    Science.gov (United States)

    Pasetto, Marco; Baldo, Nicola

    2010-09-15

    The paper presents the results of a laboratory study aimed at verifying the use of two types of electric arc furnace (EAF) steel slags as substitutes for natural aggregates, in the composition of base course and road base asphalt concrete (BBAC) for flexible pavements. The trial was composed of a preliminary study of the chemical, physical, mechanical and leaching properties of the EAF steel slags, followed by the mix design and performance characterization of the bituminous mixes, through gyratory compaction tests, permanent deformation tests, stiffness modulus tests at various temperatures, fatigue tests and indirect tensile strength tests. All the mixtures with EAF slags presented better mechanical characteristics than those of the corresponding asphalts with natural aggregate and satisfied the requisites for acceptance in the Italian road sector technical standards, thus resulting as suitable for use in road construction. Copyright 2010 Elsevier B.V. All rights reserved.

  19. Dynamic stability of a curved pipe bent in the arc of a circle on hinge ...

    Indian Academy of Sciences (India)

    Sofia e-mail: dlolov@yahoo.com; lilkova−fhe@uacg.bg. MS received 12 September 2005; revised 29 April 2006. Abstract. Curved pipes conveying fluids are investigated in the paper. Methods of numerical solution of the dynamic stability of a pipe in its plane are developed. An example of a curved pipe is solved by these ...

  20. Low and Non-waste Process Technology: The Development of a High Calorific Fuel Gas from Waste Oil Using Electric Arc Cracking.

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Joon Hyung; Kim, Jeong Guk; Kim, In Tae; Cho, Kwang Hun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Oh, Yang Hwan; Kim, Su Joung [Teko Environment Company Limited, Seoul (Korea, Republic of); Seo, Yong Chil; Song, Geum Ju; Sim, Sang Geul [Yonsei University, Seoul (Korea, Republic of)

    1997-12-01

    A laboratory scale unit(5kg/hr) of high calorific fuel gas generator from waste oil by electric arc cracking is developed and made test runs with the collected waste oil at car repair shops to observe its performance and acceptability for various operating conditions. About 60-65% of total amount of generated gas is composed of hydrogen, acetylene and ethylene. Total calorific value of the product gas shows about 10,000 kcal/kg and it is acceptable to use for fuel gas in the industry. The optimum temperature of waste oil for the production of higher calorific fuel gas is found to be 40 deg C. The average size of soot collected from the equipment is 0.3 {mu}m and it could be utilized as carbon black after detail analysis. The generation rate of product fuel gas is 100 - 140 L/kWh and the economic assessment shows that the equipment cost could be recovered within two years. Further studies on scale-up of the equipment and the development of an new electrode system having less consumption but higher stability are required. 18 refs., 13 tabs., 15 figs. (author)

  1. Geothermal Potential of the Cascade and Aleutian Arcs, with Ranking of Individual Volcanic Centers for their Potential to Host Electricity-Grade Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Shevenell, Lisa [ATLAS Geosciences, Inc., Reno, NV (United States); Coolbaugh, Mark [ATLAS Geosciences, Inc., Reno, NV (United States); Hinz, Nick [Univ. of Nevada, Reno, NV (United States); Stelling, Pete [Western Washington Univ., Bellingham, WA (United States); Melosh, Glenn [GEODE, Santa Rosa, CA (United States); Cumming, William [Cumming Geoscience, Santa Rosa, CA (United States)

    2015-10-16

    This project brings a global perspective to volcanic arc geothermal play fairway analysis by developing statistics for the occurrence of geothermal reservoirs and their geoscience context worldwide in order to rank U.S. prospects. The focus of the work was to develop play fairways for the Cascade and Aleutian arcs to rank the individual volcanic centers in these arcs by their potential to host electricity grade geothermal systems. The Fairway models were developed by describing key geologic factors expected to be indicative of productive geothermal systems in a global training set, which includes 74 volcanic centers world-wide with current power production. To our knowledge, this is the most robust geothermal benchmark training set for magmatic systems to date that will be made public.

  2. Parametric Study of Hybrid Argon-Water Stabilized Electric Arc under Subsonic and Supersonic Regimes

    Czech Academy of Sciences Publication Activity Database

    Jeništa, Jiří; Hrabovský, Milan; Nishiyama, H.; Takana, H.; Bartlová, M.; Aubrecht, V.

    2010-01-01

    Roč. 14, č. 1 (2010), s. 63-76 ISSN 1093-3611 R&D Projects: GA ČR GA202/08/1084 Institutional research plan: CEZ:AV0Z20430508 Keywords : argon mass flow rate * divergence of radiation flux * partial characteristics * reabsorption * shock diamonds * water plasma torch Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.189, year: 2010

  3. Methodology for electrical studies in industrial networks including the study of electric arc; Metodologia para los estudios electricos en redes industriales incluyendo el estudio de arco electrico

    Energy Technology Data Exchange (ETDEWEB)

    Rasgado Casique, Jose Pepe; Silva Farias, Jose Luis [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: jrasgado@iie.org.mx; jlsilva@iie.org.mx

    2010-11-15

    This article presents a methodology for conducting electrical studies in industrial networks. The methodology included the study of arc flash as a very important area of current basic electrical studies, such as power flow, short circuit and coordination. The aim of this study is to determine the Personal Protective Equipment (PPE) and flash protection boundary for personnel working with or near energized equipment, based on the IEEE Std 1584-2004 and NFPA-70E- 2004. Also included are criteria and recommendations to reduce incident energy level (cal/cm{sup 2}). At work we used a distribution network for industrial type test. The studies were carried out using a commercial program for the analysis of electrical networks. [Spanish] En este articulo se presenta una metodologia para llevar a cabo los estudios electricos en redes industriales. En la metodologia se incluye al estudio de arco electrico como un area muy importante de los estudios electricos basicos actuales, como: flujos de potencia, cortocircuito y coordinacion de protecciones. El objetivo de dicho estudio es determinar el Equipo de Proteccion Personal (EPP) apropiado y los limites de proteccion para el personal que opera con o cerca de equipo energizado, con base en las normas IEEE Std. 1584-2004 y la NFPA-70E-2004. Ademas, se incluyen criterios y recomendaciones para disminuir el nivel de energia incidente (cal/cm{sup 2}). En el trabajo se utilizo una red de distribucion tipo industrial de prueba. Los estudios se llevaron a cabo utilizando un programa comercial para el analisis de redes electricas.

  4. Analysis of a Major Electric Grid -- Stability and Adaptive Protection

    Science.gov (United States)

    Alanzi, Sultan

    system conditions. This dissertation introduces a combination of quadrilateral and mho characteristics to create a distance relay with a mushroom shape in R-X diagrams. This new relay offers larger protective reach with a lower limitation on loadability. When major disturbances occur, the power balance between load and generation might be disturbed causing the generators to lose synchronism (to be out-of-step) with each other. Out-of-step protection against power swings is essential to provide supervising signals for distance relays to mitigate the effects of the disturbance. A new R-X criterion is proposed to identify out-of-step conditions for large and complex power systems, such as KEG. A proposed Adaptive Out-of-Step Relay (AOSR) will monitor power system conditions and adjust the relay reach accordingly for better power swing classification. When unstable swings are detected, controllable tripping signals are initiated and system separation will create small subsystems or islands of the power system. These smaller systems will be created to achieve a balance of load and available generation. The electric power system chosen to study and to illustrate the criteria for the proposed adaptive relays was that of the country of Kuwait. The small oil-rich country of Kuwait has been dealing with an electric energy crisis that started summer 2006. With a dry dessert climate and intensely hot summers, the 3.6 million residents of Kuwait depend on continuously operated A/C units for living. This is the major reason why the peak load in a summer month reaches almost 11,000 MW while the peak load in a winter month does not exceed 5,000 MW. The Kuwait Electric Grid (KEG) is modelled and analyzed using Power Analytics' software known as PaladinRTM DesignBase(TM). Performance studies produce data to examine distance and out-of-step protection. Power Flow (PF), Short Circuit Analysis (SCA), and Transient Stability Analysis (TSA) are used to verify the model of KEG. These studies

  5. Dynamic Stability Enhancement of a Multi Machine Electric Power System Using Unified Power Flow Controller

    OpenAIRE

    Ahmad Memaripour; Sayed Mojtaba Shirvani Boroujeni; Reza Hemmati

    2011-01-01

    This study presents the application of Unified Power Flow Controller (UPFC) to improvement dynamic stability of a multi-machine electric power system installed with UPFC. Since UPFC is considered to mitigate Low Frequency Oscillations (LFO) and stability enhancement, therefore a supplementary stabilizer based on UPFC (like power system stabilizer) is designed to reach the defined purpose. Intelligence optimization methods such as Particle Swarm Optimization (PSO) and Genetic Algorithms (GA) a...

  6. Hydrometallurgical process for zinc recovery from electric arc furnace dust (EAFD). Part II: Downstream processing and zinc recovery by electrowinning.

    Science.gov (United States)

    Tsakiridis, P E; Oustadakis, P; Katsiapi, A; Agatzini-Leonardou, S

    2010-07-15

    The characterization and the agitation leaching of electric arc furnace dust (EAFD) by diluted sulphuric acid have been studied in Part I, as a separate article. The aim of the present research work (Part II) is the development of a purification process of the leach liquor for the recovery of high-purity zinc by electrowinning. The proposed hydrometallurgical process consists of the following four (4) unit operations: (1) Removal of iron as easily filterable crystalline basic sulphate salt of the jarosite type, at atmospheric pressure, by chemical precipitation at pH: 3.5 and 95 degrees C. (2) Zinc solvent extraction by Cyanex 272 at pH: 3.5, T: 40 degrees C, with 25% extractant concentration. (3) Stripping of the loaded organic phase by zinc spent electrolyte (62.5 g/L Zn(2+)) at T: 40 degrees C with diluted H(2)SO(4) (3 mol/L). (4) Zinc electrowinning from sulphate solutions (at 38 degrees C) using Al as cathode and Pb as anode. The acidity of the electrolyte was fixed at 180 g/L H(2)SO(4), while the current density was kept constant at 500 A/m(2). 2010 Elsevier B.V. All rights reserved.

  7. Shape of argon spectral lines emitted from an electric arc (P=760 Torr). Study and application of pressure broadening

    International Nuclear Information System (INIS)

    Kretzas, Dimitrios.

    1978-01-01

    We have studied the broadening and shift of argon spectral lines corresponding to 3p 5 5p-3p 5 4s and 3p 5 4p-3p 5 4s transitions emitted from an electric arc burning under atmospheric pressure. We have revealed the broadening due to neutral atoms pressure effect, distinguishing the transitions whose lower level is a metastable one (1s 3 and 1s 5 ) or a level of strong (1s 2 ) or feeble resonance (1s 4 ). In this study we have employed a mixture of argon (98%) and hydrogen (2%); hydrogen's feeble proportion does not perturb much the discharge and is very suitable for the measure of the electronic density. The important departure of L.T.E. has guided us to imagine and apply an original method to measure the temperature and the overpopulation of the neutral atoms in the fondamental state. Our method which is independent of the existence of L.T.E. is based on the different behavior of the spectral lines which are under the influence of the resonance or Van der Waals broadening. The measure of the broadening constants which in the resonance case are independent of the temperature and vary as Tsup(0,3) for V.d.W's broadening, give us a suitable tool to measure the density and the temperature of the neutral atoms [fr

  8. Test Plan: Phase 1 demonstration of 3-phase electric arc melting furnace technology for vitrifying high-sodium content low-level radioactive liquid wastes

    International Nuclear Information System (INIS)

    Eaton, W.C.

    1995-01-01

    This document provides a test plan for the conduct of electric arc vitrification testing by a vendor in support of the Hanford Tank Waste Remediation System (TWRS) Low-Level Waste (LLW) Vitrification Program. The vendor providing this test plan and conducting the work detailed within it [one of seven selected for glass melter testing under Purchase Order MMI-SVV-384216] is the US Bureau of Mines, Department of the Interior, Albany Research Center, Albany, Oregon. This test plan is for Phase I activities described in the above Purchase Order. Test conduct includes feed preparation activities and melting of glass with Hanford LLW Double-Shell Slurry Feed waste simulant in a 3-phase electric arc (carbon electrode) furnace

  9. Electric arc furnace dust utilization in iron ore sintering: influence of particle size; Utilizacao da poeira de aciaria eletrica na sinterizacao de minerio de ferro: influencia da granulometria

    Energy Technology Data Exchange (ETDEWEB)

    Telles, V.B.; Junca, E.; Rodrigues, G.F.; Espinosa, D.C.R.; Tenorio, J.A.S., E-mail: victor_bridit@hotmail.co [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Engenharia Metalurgica e de Materiais

    2010-07-01

    The aim of this work was to study the utilization of electric arc furnace dust (EAFD) generated in steelmaking by electric arc furnace (EAF) as raw material in iron ore sintering. The waste was characterized by size, chemical composition and X-ray diffraction. The physical characterization showed that 90% of the particles have a size less then 1,78 {mu}m and the material have the tendency to agglomerate. The waste were submitted to a pre-agglomeration prior to its incorporation in the sinter. The influence on the addition of the waste with different granulometry in the iron or sinter production were analyzed by sinter characterization and sintering parameters. (author)

  10. Electrical characteristics of a free-burning direct-current argon arc operating between 90 and 563 kilowatts with two types of cathodes

    Science.gov (United States)

    Curtis, H. B.; Decker, A. J.

    1975-01-01

    The electrical characteristics of a high-power, long-lived, free-burning dc argon arc are presented. Empirical formulas relating voltage to current, electrode separation, and operating pressure are given for two types of cathodes: a typical point tip cathode and a cathode with a 1.27-cm-(0.5-in.-) diameter crater in the tip. Power was varied from 90 to 563 kW. A discussion of the cathode with the crater tip is given.

  11. Recycling of electric arc furnace (EAF dust for use in steel making process

    Directory of Open Access Journals (Sweden)

    José Alencastro de Araújo

    2014-07-01

    Full Text Available The EAF dust is listed as hazardous waste from specific source, K061, according to ABNT 10004:2004 and constitutes one of the major problems of electrical steel plant. This work suggests recycling of the EAF dust by sintering of a composite, pre-cast agglomerate (PCA consisting of EAF dust agglomerate to coke particles, mill scale and ceramic fluorite into pellets. The work was divided into three stages, in the first stage the technical viability of using only solid waste industrial to produce a PCA was observed, in the second phase, the main effects between the components of the PCA to obtain the optimal formulation was tested. In the third phase the intensity of the variables, coke and fluorite ceramics, for removing zinc of PCA was checked. Every stage was chemically analyzed by X-ray fluorescence spectrometer and X-ray diffraction. The first two stages of the production PCA were carried out in a pilot plant sintering downstream and the third phase in a pilot plant upstream. As a result of the process two by-products were obtained, the pre-cast agglomerated, PCA, with total iron content exceeding 70%, object of the process of sintering and zinc dust, containing more than 50% zinc resulting from volatilization of this metal during the sintering process and collected by bag filter. In addition, approximately 90% of lead and cadmium contained in the initial EAF dust was extracted.

  12. The influence of remelting parameters of the electric arc and conventional tempering on the tribological resistance of high speed steel HS 6-5-2

    Directory of Open Access Journals (Sweden)

    A. Dziedzic

    2011-07-01

    Full Text Available The present thesis depicts the results of the research of tribological high speed steel HS 6-5-2 remelted with the electric arc. Steel was remelted with different parameters. The amperage of electric arc was changed, the scanning speed was changed and the single, overlapping remeltings were used. There was also the influence of conventional tempering defined, which was conducted after remelting on the tribological resistance of hardened steel. For the previously mentioned processing variants, the intensity of tribological wear was defined and the linear wear were presented, and the friction coefficients. The type of tribological wear was also given, present during the friction, technically dry, of the hardened steel. The lower intensity of tribological wear was received for the single remelting by electric arc of 50 and 70A. Using the overlapping remeltings for the strengening of the surface layer of the high speed steel HS 6-5-2 causes the increase of the intensity of tribological wear in comparison to the steel with the single remelting. The conventional tempering leads to the decrease of the intensity of tribological wear.

  13. EHPS Handling Stability Analysis of Electric Bus Based on System Identification Method

    Science.gov (United States)

    Zhang, Ni; Liu, Hai-mei; Bei, Shao-yi; Li, Bo; Zhao, Jing-bo

    2017-09-01

    Electric hydraulic assist force steering system (EHPS system) is the steering system of electric bus, this paper presents a method of EHPS handling stability analysis based on system identification method according to the handling stability of EHPS system for electric bus. The simulation model of electro-hydraulic assist force steering system EHPS is established by using the software AMESim, and making a quantitative analysis on the characteristics of the electric assist force assisted steering system, the assist force response and stability. At the same time, we study the stability of vehicle, including hunting, transient response, return experiment, the results show that the HPS and EHPS by comparing the simulation: It improves the portability, road sense, transient response and return performance after loading the system, which verifiy the effectiveness of the control strategy that improves vehicle steering performance, and it provides the basis for the optimization of control methods in the future.

  14. Power System Transient Stability Improvement Using Demand Side Management in Competitive Electricity Markets

    DEFF Research Database (Denmark)

    Hu, Weihao; Wang, Chunqi; Chen, Zhe

    2012-01-01

    for demand side management generates different load profiles and may provide an opportunity to improve the transient stability of power systems with high wind power penetrations. In this paper, the idea of the power system transient stability improvement by using optimal load response to the electricity...

  15. Influence of Mechanically Activated Electric Arc Furnace Slag on Compressive Strength of Mortars Incorporating Curing Moisture and Temperature Effects

    Directory of Open Access Journals (Sweden)

    Muhammad Nasir Amin

    2017-07-01

    Full Text Available In this study, the influence of mechanically activated electric arc furnace slag (EAFS was investigated through compressive strength tests on 50 mm mortar cubes. The objective was to convert the wasteful EAFS into a useful binding material to reduce the cement content in concrete without compromising strength and economy. Four different groups of mortar were cast which include control mortar, reference fly ash mortar, mortar containing EAFS to determine its optimum fineness and replacement with cement, mortar blend containing fly ash and EAFS of optimum fineness. EAFS were identified with respect to its fineness as slag ground (SG, slag-fine (SF 100% passing 75 µm sieve, and slag-super-fine (SSF 100% passing 45 µm sieve. Compressive strength was measured according to ASTM C109. Specimens were cured under different temperatures and moisture to incorporate the effects of normal and hot environmental conditions. Compressive strength of mortars increases with fineness of EAFS and its strength activity index matches the ASTM C989 blast furnace slag (BFS Grade 80 up to 30% cement substitution and Grade 100 when 10% cement substituted with SSF. The influence of curing temperatures was also significant in mortars containing SG or 10% SF where strength decreased with increasing curing temperature. However, a 20–30% and 20% cement substitution with SF produced strength comparable to control and reference fly ash mortars under moderate (40 °C and high curing temperature (60 °C, respectively. The utilization of EAFS as binder in concrete may reduce needs for cement, as well as save environment and natural resources from depletion.

  16. Application of a radiant heat transfer model to complex industrial reactive flows: combustion chambers, electric arcs; Application d`un modele de transfert radiatif a des ecoulements reactifs industriels complexes: chambres de combustion, arcs electriques

    Energy Technology Data Exchange (ETDEWEB)

    Mechitoua, N.; Dalsecco, S.; Delalondre, C.; Simonin, O. [Electricite de France (EDF), 78 - Chatou (France). Lab. National d`Hydraulique

    1996-12-31

    The direction of studies and researches (DER) of Electricite de France (EdF) has been involved for several years in a research program on turbulent reactive flows. The objectives of this program concern: the reduction of pollutant emissions from existing fossil-fueled power plants, the study of new production means (fluidized beds), and the promotion of electric power applications in the industry. An important part of this program is devoted to the development and validation of 3-D softwares and to the modeling of physical phenomena. This paper presents some industrial applications (furnaces, boilers, electric arcs) for which radiant heat transfers play an important role and the radiation models used. (J.S.) 8 refs.

  17. Effect of mobilities and electric field on the stability of magnetized positive column

    International Nuclear Information System (INIS)

    Dogra, V.K.; Uberoi, M.S.

    1983-01-01

    The effect of ratio of the mobilities of electrons and ions and non-dimensional electric field, on the stability of magnetized positive column for all unstable modes is studied in a self-consistent formulation for the perturbations of plasma density and electric potential. The minimum non-dimensional electric field at which magnetized positive column becomes unstable for different ratios of the mobilities of electrons and ions is also investigated. (author)

  18. Stability of negative ionization fronts: Regularization by electric screening?

    International Nuclear Information System (INIS)

    Arrayas, Manuel; Ebert, Ute

    2004-01-01

    We recently have proposed that a reduced interfacial model for streamer propagation is able to explain spontaneous branching. Such models require regularization. In the present paper we investigate how transversal Fourier modes of a planar ionization front are regularized by the electric screening length. For a fixed value of the electric field ahead of the front we calculate the dispersion relation numerically. These results guide the derivation of analytical asymptotes for arbitrary fields: for small wave-vector k, the growth rate s(k) grows linearly with k, for large k, it saturates at some positive plateau value. We give a physical interpretation of these results

  19. The Possibility of Decreasing 50-Hz Electric Field Exposure near 400-kV Power Lines with Arc Flash Personal Protective Equipment

    Directory of Open Access Journals (Sweden)

    Leena Korpinen

    2016-09-01

    Full Text Available Various guidelines for the protection of human beings against possible adverse effects resulting from exposure to electromagnetic fields (EMFs have been published with a view towards continual improvement; therefore, decreasing exposure is an important research area. The aim of this study was to investigate the possibility of decreasing electric field exposure with arc flash rated personal protective equipment (PPE, which in this case was a set of coveralls, and to compare the measurement results to calculations using the helmet-mask measuring system. We collected the data under a 400-kV power line. The test person stood on isolated aluminum paper, and the current between the ground and the aluminum paper was measured. When the test subject wore the arc flash PPE, the current to the ground was only 9.5% of the current measured when wearing normal clothes, which represents a clear decrease in exposure.

  20. The Possibility of Decreasing 50-Hz Electric Field Exposure near 400-kV Power Lines with Arc Flash Personal Protective Equipment.

    Science.gov (United States)

    Korpinen, Leena; Pirkkalainen, Herkko; Heiskanen, Timo; Pääkkönen, Rauno

    2016-09-23

    Various guidelines for the protection of human beings against possible adverse effects resulting from exposure to electromagnetic fields (EMFs) have been published with a view towards continual improvement; therefore, decreasing exposure is an important research area. The aim of this study was to investigate the possibility of decreasing electric field exposure with arc flash rated personal protective equipment (PPE), which in this case was a set of coveralls, and to compare the measurement results to calculations using the helmet-mask measuring system. We collected the data under a 400-kV power line. The test person stood on isolated aluminum paper, and the current between the ground and the aluminum paper was measured. When the test subject wore the arc flash PPE, the current to the ground was only 9.5% of the current measured when wearing normal clothes, which represents a clear decrease in exposure.

  1. Obtaining in an electric arc furnace alloys of the Fe-Mn-Cr-C system and slag destined to the development of welding consumables

    Directory of Open Access Journals (Sweden)

    Lorenzo Perdomo-González

    2018-01-01

    Full Text Available The production of chromium manganese ferroalloys for the use in the development of alloying loads of welding consumables is presented. On the basis of variations in the proportions of the chromium and manganese minerals in the loads, different combinations are established, which allow obtaining multicomponent ferroalloys with composition ranging from 9 to 32 % chromium and from 24 to 65 % manganese. The melting-reduction process is carried out in an electric arc furnace with a graphite crucible and with the presence of coke as a reducing component which guarantees the obtaining of high carbon alloys (5–6 %. The use of the multicomponent ferroalloy in the formulation of welding consumables simplifies and makes cheaper the obtaining of these materials. As result of metallurgical processing, slag formed by the silicon, aluminum, magnesium, manganese and calcium oxides are obtained, which are feasible to use in the production of flux matrices for submerged arc welding process.

  2. Y2K lessons learned for electric grid stability

    International Nuclear Information System (INIS)

    Gueorguiev, B.; Ianev, I. L.; Purvis, E. E.

    2000-01-01

    Y2K was an example of a worldwide infrastructure threat. Actions to understand infrastructure risks and mitigate infrastructure threats are a continuing and increasing part of the worlds corporate, government, and international organizations systems, and the severe implications of infrastructure failures to the health, safety, and financial well being of people and organizations are the deriving force. The IAEA conducted a number of Y2K related activities in nuclear power and fuel cycle activities. A set of these activities address the interface between electric power generation facilities and electric power grids in the region of Eastern Europe and the countries of the former Soviet Union. This addressed a continuing infrastructure risks and actions to mitigate these risk. The results were shown by events to have made positive contributions. The potential loss of nuclear power plant generation is a significant risk to electric power grids, an important critical infrastructure. Not only does the threat constitute a problem with the potential loss of the grid, loss of the electric power grid increases the probability of accidents in nuclear power plants. Recognizing that these activities addressed only one area of infrastructure risk in one region, there are some key lessons that were learned that could have general applicability

  3. ???????? ??????? ???????? ????? ?? ?????? ArcGIS ??? ?????? ??????????????? ?????????? ????? ???????????? ?????????? ???????????

    OpenAIRE

    ?????, ?.; ?????, ?.; ???????????, ?.; ????????, ?.

    2016-01-01

    ?????????? ?????? ????????? ???????????????? ??????? ??? ???????? ????? ??? ???????????? ????????? ????? ?????? ?? ????????? ???????????? ?????????? ???????????. ??????? ??????? ??????? ???????, ???????????? ?? ???? ??????????? ???????????? ArcGIS. ?????????? ?????????? ?????????? ???????? ?? ??????????? ?????????? ? ????????????? ??????? ArcGIS Online ?? ??????? Collector for ArcGIS. ???????? ???? ???????? ????????????????? ??????? ??? ????? ?????? ? ?????????????? ?????? ????? ???????? ?? ?...

  4. Electrical, optical, and structural properties of thin films with tri-layers of AZO/ZnMgO/AZO grown by filtered vacuum arc deposition

    Energy Technology Data Exchange (ETDEWEB)

    Gontijo, Leonardo C. [Instituto Federal do Espirito Santo, Programa de Pos-Graduacao em Engenharia Metalurgica e de Materiais, CEP 29444-030 Vitoria, ES (Brazil); Cunha, Alfredo G. [Universidade Federal do Espirito Santo, Departamento de Fisica, CEP 29075-910 Vitoria, ES (Brazil); Nascente, Pedro A.P., E-mail: nascente@ufscar.br [Universidade Federal de Sao Carlos, Departamento de Engenharia de Materiais, CEP 13565-905 Sao Carlos, SP (Brazil)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer AZO/ZnMgO/AZO tri-layered films were grown by FCAD filtered cathodic arc deposition. Black-Right-Pointing-Pointer The films were highly transparent and presented excellent electrical resistivity. Black-Right-Pointing-Pointer The films presented optical transmittance in the visible light higher than 80%. - Abstract: Transparent conductive oxides (TCO) are indispensable as front electrode for most of thin film electronic devices such as transparent electrodes for flat panel displays, photovoltaic cells, windshield defrosters, transparent thin film transistors, and low emissivity windows. Thin films of aluminum-doped zinc oxide (AZO) have shown to be one of the most promising TCOs. In this study, three layered Al-doped ZnO (AZO)/ZnMgO/AZO heterostructures were prepared by filtered cathodic arc deposition (FCAD) on glass substrates. The objective is to find a set of parameters that will allow for improved optical and electrical properties of the films such as low resistivity, high mobility, high number of charge carriers, and high transmittance. We have investigated the effect of modifications in thickness and doping of the ZnMgO inner layer on the structural, electrical, and optical characteristics of the stacked heterostructures.

  5. Electrogravitational stability of oscillating streaming fluid cylinder ambient with a transverse varying electric field

    Directory of Open Access Journals (Sweden)

    Hasan Alfaisal

    2011-01-01

    Full Text Available Abstract The electrogravitational instability of a dielectric oscillating streaming fluid cylinder surrounded by tenuous medium of negligible motion pervaded by transverse varying electric field has been investigated for all the perturbation modes. The model is governed by Mathieu second-order integro-differential equation. Some limiting cases are recovering from the present general one. The self-gravitating force is destabilizing only in the axisymmetric perturbation for long wavelengths, while, the axial electric field interior, the fluid has strong destabilizing effect for all short and long wavelengths. The transverse field is strongly stabilizing. In the case of non-axisymmetric perturbation, the self-gravitating force is stabilizing for short and long waves, while the electric field has stabilizing effect on short waves.

  6. Hall-effect arc protector

    Science.gov (United States)

    Rankin, R.A.; Kotter, D.K.

    1997-05-13

    The Hall-Effect Arc Protector is used to protect sensitive electronics from high energy arcs. The apparatus detects arcs by monitoring an electrical conductor, of the instrument, for changes in the electromagnetic field surrounding the conductor which would be indicative of a possible arcing condition. When the magnitude of the monitored electromagnetic field exceeds a predetermined threshold, the potential for an instrument damaging are exists and the control system logic activates a high speed circuit breaker. The activation of the breaker shunts the energy imparted to the input signal through a dummy load to the ground. After the arc condition is terminated, the normal signal path is restored. 2 figs.

  7. Dynamic stability enhancement of a multimachine electric power system using STATCOM

    OpenAIRE

    BOROUJENI, Hasan Fayazi; HEMMATI, Reza; BOROUJENI, Sayed Mojtaba Shirvani

    2011-01-01

    With the expansion of electric power systems, the size and complexity of the network is increased. One of the most important drawbacks of network expansion is the reduction in the damping torque of the whole system. The lack of damping torque can lead to fluctuations and instability in the power system. With regard to this problem, power system stabilizers (PSSs) have been widely utilized to improve power system stability. However, due to some drawbacks of the conventional PSSs, the ...

  8. Development and Testing of an Experimental Polysensory Instructional System for Teaching Electric Arc Welding Processes. Report No. 24. Final Report.

    Science.gov (United States)

    Sergeant, Harold A.

    The population of the study consisted of 15 high school industrial arts students, 10 freshman and sophomore college students, and 10 adults. A polysensory, self-pacing instructional system was developed which included (1) pretests and post tests, (2) a general instruction book, (3) equipment to practice arc welding, (4) programed instruction…

  9. The influence of conventional tempering on the tribiological resistance of the high speed steel HS 6-5-2 remelted with electric arc

    Directory of Open Access Journals (Sweden)

    A. Dziedzic

    2010-04-01

    Full Text Available The influence of the conventional tempering has been defined in the paper in two different temperatures 560C and 600C on the intensity of tribological wear of the high speed steel HS 6-5-2 remelted with the electric arc. The influence of tempering on the intensity of wear for the steel has been tested with the single and overlapping remeltings. Moreover, the types of the tribological wear appeared during the friction. The tribiological research, were done in the technically dry friction conditions on a testing machine of the pin-on-disc T-01M. Conducting the conventional process of tempering after the remelting with the electric arc, causes the decrease of the intensity of the tribological wear. The smallest intensity of tribiological wear after tempering was observed in the high speed steel HS 6-5-2 with the single remelting of the current 70 A. The main wear type appearing during the research was the abrasion and adhesive wear.

  10. Método integral configurable y flexible de ensayo de materiales consumibles de soldadura por arco eléctrico. // Integral, flexible and shaped method for electric arc welding consumable materials test.

    Directory of Open Access Journals (Sweden)

    A. García Rodríguez

    2005-05-01

    relationship between natural and/or artificial intelligence technical, expertssystems, data bases work, simulation, and practical realization of process while are registered certain parameters of the electric arc digitalstatistic processed and related to the results of the welded joint characterization. The method allows appropriate information registers foreach aspect of the process that require process of certification of quality of materials, like the investigation directed to optimization of thematerial chemical composition and physical properties obtaining very best qualities at certain process. It is also possible to obtain electricarc parameters data bases useful for search, development and valuation of methods and algorithms for real time monitoring of weldingquality during fixed technologic process of electric arc welding.Key words: Test, materials, welding, electric arc, stability, quality, simulation, optimization, welded joint. 

  11. Vehicle state estimator based regenerative braking implementation on an electric vehicle to improve lateral vehicle stability

    NARCIS (Netherlands)

    Jansen, S.T.H.; Boekel, J.J.P. van; Iersel, S.S. van; Besselink, I.J.M.; Nijmeijer, H.

    2013-01-01

    The driving range of electric vehicles can be extended using regenerative braking. Regenerative braking uses the elctric drive system, and therefore only the driven wheels, for decelerating the vehicle. Braking on one axle affects the stability of the vehicle, especially for road conditions with

  12. Concurrent temporal stability of the apparent electrical conductivity and soil water content

    Science.gov (United States)

    Knowledge of spatio-temporal soil water content (SWC) variability within agricultural fields is useful to improve crop management. Spatial patterns of soil water contents can be characterized using the temporal stability analysis, however high density sampling is required. Soil apparent electrical c...

  13. Gas phase condensation of few-layer graphene with rotational stacking faults in an electric-arc

    OpenAIRE

    Karmakar, Soumen; Nawale, Ashok B.; Lalla, Niranjan P.; Sathe, Vasant G.; Mathe, Vikas L.; Das, Asoka K.; Bhoraskar, Sudha V.

    2012-01-01

    We report the synthesis efficiency of few-layer graphene (FLG) in an external magnetic field modulated DC carbon arc in different non-reactive buffer gases. The effects of buffer gases on the anode erosion rate and the cathode deposit (CD) formation rate have been investigated during the synthesis of FLG. The constituents of the as-synthesized CDs were investigated using transmission electron microscopy, selected area electron diffraction, Raman spectroscopy and X-ray diffraction analysis. A ...

  14. Vastly enhancing the chemical stability of phosphorene by employing an electric field.

    Science.gov (United States)

    Gao, Junfeng; Zhang, Gang; Zhang, Yong-Wei

    2017-03-23

    Currently, a major hurdle preventing phosphorene from various electronic applications is its rapid oxidation under ambient conditions. Thus how to enhance its chemical stability by suppressing oxidation becomes an urgent task. Here, we reveal a highly effective procedure to suppress the oxidation of phosphorene by employing a suitable van der Waals (vdW) substrate and a vertical electric field. Our first-principles study shows that the phosphorene-MoSe 2 vdW heterostructure is able to reverse the stability of physisorption and chemisorption of molecular O 2 on phosphorene. With further application of a vertical electric field of -0.6 V Å -1 , the energy barrier for oxidation is able to further increase to 0.91 eV, leading to a 10 5 times enhancement in its lifetime compared with that without using the procedure at room temperature. Our work presents a viable strategy to vastly enhance the chemical stability of phosphorene in air.

  15. Small Signal Stability of the International Space Station/JEM Electric Power Network

    Science.gov (United States)

    Komatsu, Masaaki; Yanabu, Satoru

    2005-05-01

    When designing a large distributed direct current (dc) power systems such as telecommunications and spacecraft power systems, special attention must be placed on the electrical stability and control of the system and individual load on the systems. For a large-scale Electric Power System (EPS), it is not feasible to design the entire system as a whole. Instead, the system can be defined in term of numerous small blocks, and each block then designed individually. The individual blocks are then integrated to form a complete system. The International Space Station (ISS) is one of good example for these issue and concerns as a large-scale Space Power System.A crucial factor in design and implementation of any dc power network using switching converters is the stability of the system under all expected conditions of load and transition perturbations.The principles of stability are applicable to the developments of payloads for the ISS and the developments of distributed dc power systems in general. For the small signal stability criterion, a minimum gain and phase margin is based on the complex load and source impedances at the system interface. The concept of gain or phase separation is also related to gain and phase margin, providing means to specify stability with load and source impedance requirements.This paper describes the approach of the small signal stability analysis for a large-scale space power network showing NASA/JAXA joint EPS verification data.

  16. The investigation of movement dynamics of an AC electric arc attachment along the working surface of a hollow cylindrical electrode under the action of gas-dynamic and electromagnetic forces

    International Nuclear Information System (INIS)

    Surov, A V; Popov, S D; Serba, E O; Nakonechny, G V; Spodobin, V A; Ovchinnikov, R V; Kumkova, I I; Shabalin, S A

    2012-01-01

    Stationary electric arc alternating current plasma torches are used today for realization of plasma chemical technologies requiring relatively high energy input. Waste treatment is one these directions. The paper reports on experiment results directed towards the increase in the lifetime characteristics of electrode units of the powerful high-voltage electric-arc AC plasma torches. The solution to the problem of obtainment the uniform wear of a copper hollow cylindrical electrode achieved by the controlled movement of the arc attachment along the working surface was offered. Organization of gas supply in the near electrode area and application of alternating magnetic field ensured movement of arc attachment along the surface with average speed from 2 to 14 m/s. Arc current was about 47 A and 84 A, gas flow rate in near electrode area was about 5 and 4.5 g/s. Due to researches on the experimental prototype of a hollow cylindrical electrode, the erosion of its material reached only 3 μg/C, that enables production of the electrode assembly with life time above 1000 hours at currents in the arc up to 100–200 A.

  17. Stability and dynamic performance of the General Electric Boiling Water Reactor. Licensing topical report

    International Nuclear Information System (INIS)

    1977-01-01

    The analytical methods used to evaluate the stability of GE boiling water reactors is presented. The physical and phenomenological characteristics pertinent to stability analyses are described for the following three configurations evaluated in the BWR design process: total plant, core, and channel hydrodynamic characteristics. Given is a description of the stability criteria and its theoretical basis followed by a description of the analytical methods used in evaluating the BWR. These analyses were derived from and supported by test data from current operating General Electric boiling water reactors. In addition, a parametric evaluation of the BWR is made for the total plant, reactor core, and channel hydrodynamic performance over a wide range of operating conditions. The information presented demonstrates the technical proficiency of the design and substantiates the operational stability characteristics of the integrated Nuclear Steam Supply System

  18. Power Stabilization Strategy of Random Access Loads in Electric Vehicles Wireless Charging System at Traffic Lights

    Directory of Open Access Journals (Sweden)

    Linlin Tan

    2016-10-01

    Full Text Available An opportunity wireless charging system for electric vehicles when they stop and wait at traffic lights is proposed in this paper. In order to solve the serious power fluctuation caused by random access loads, this study presents a power stabilization strategy based on counting the number of electric vehicles in a designated area, including counting method, power source voltage adjustment strategy and choice of counting points. Firstly, the circuit model of a wireless power system with multi-loads is built and the equation of each load is obtained. Secondly, after the counting method of electric vehicles is stated, the voltage adjustment strategy, based on the number of electric vehicles when the system is at a steady state, is set out. Then, the counting points are chosen according to power curves when the voltage adjustment strategy is adopted. Finally, an experimental prototype is implemented to verify the power stabilization strategy. The experimental results show that, with the application of this strategy, the charging power is stabilized with the fluctuation of no more than 5% when loads access randomly.

  19. Effects of Hall current and electrical resistivity on the stability of gravitating anisotropic quantum plasma

    Science.gov (United States)

    Bhakta, S.; Prajapati, R. P.

    2018-02-01

    The effects of Hall current and finite electrical resistivity are studied on the stability of uniformly rotating and self-gravitating anisotropic quantum plasma. The generalized Ohm's law modified by Hall current and electrical resistivity is used along with the quantum magnetohydrodynamic fluid equations. The general dispersion relation is derived using normal mode analysis and discussed in the parallel and perpendicular propagations. In the parallel propagation, the Jeans instability criterion, expression of critical Jeans wavenumber, and Jeans length are found to be independent of non-ideal effects and uniform rotation but in perpendicular propagation only rotation affects the Jeans instability criterion. The unstable gravitating mode modified by Bohm potential and the stable Alfven mode modified by non-ideal effects are obtained separately. The criterion of firehose instability remains unaffected due to the presence of non-ideal effects. In the perpendicular propagation, finite electrical resistivity and quantum pressure anisotropy modify the dispersion relation, whereas no effect of Hall current was observed in the dispersion characteristics. The Hall current, finite electrical resistivity, rotation, and quantum corrections stabilize the growth rate. The stability of the dynamical system is analyzed using the Routh-Hurwitz criterion.

  20. Structure, electrical characteristics, and high-temperature stability of aerosol jet printed silver nanoparticle films

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Md Taibur; McCloy, John; Panat, Rahul, E-mail: rahul.panat@wsu.edu, E-mail: rvchintalapalle@utep.edu [School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99163 (United States); Ramana, C. V., E-mail: rahul.panat@wsu.edu, E-mail: rvchintalapalle@utep.edu [Department of Mechanical Engineering, University of Texas at El Paso, El Paso, Texas 79968 (United States)

    2016-08-21

    Printed electronics has emerged as a versatile eco-friendly fabrication technique to create sintered nanoparticle (NP) films on arbitrary surfaces with an excellent control over the film microstructure. While applicability of such films for high-temperature applications is not explored previously, herein we report the high-temperature electrical stability of silver (Ag) metal NP films fabricated using an Aerosol Jet based printing technique and demonstrate that this behavior is dictated by changes in the film microstructure. In-situ high temperature (24–500 °C) impedance spectroscopy measurements show that the real part of the impedance increases with increasing temperature up to 150 °C, at which point a decreasing trend prevails until 300 °C, followed again by an increase in impedance. The electrical behavior is correlated with the in-situ grain growth of the Ag NP films, as observed afterwards by scanning electron microscopy and X-ray diffraction (XRD), and could be tailored by controlling the initial microstructure through sintering conditions. Using combined diffraction and spectroscopic analytical methods, it is demonstrated the Aerosol Jet printed Ag NP films exhibit enhanced thermal stability and oxidation resistance. In addition to establishing the conditions for stability of Ag NP films, the results provide a fundamental understanding of the effect of grain growth and reduction in grain boundary area on the electrical stability of sintered NP films.

  1. Stability of horizontal viscous fluid layers in a vertical arbitrary time periodic electric field

    Science.gov (United States)

    Bandopadhyay, Aditya; Hardt, Steffen

    2017-12-01

    The stability of a horizontal interface between two viscous fluids, one of which is conducting and the other is dielectric, acted upon by a vertical time-periodic electric field is considered theoretically. The two fluids are bounded by electrodes separated by a finite distance. For an applied ac electric field, the unstable interface deforms in a time periodic manner, owing to the time dependent Maxwell stress, and is characterized by the oscillation frequency which may or may not be the same as the frequency of the ac electric field. The stability curve, which relates the critical voltage, manifested through the Mason number—the ratio of normal electric stress and viscous stress, and the instability wavenumber at the onset of the instability, is obtained by means of the Floquet theory for a general arbitrary time periodic electric field. The limit of vanishing viscosities is shown to be in excellent agreement with the marginal stability curves predicted by means of a Mathieu equation. The influence of finite viscosity and electrode separation is discussed in relation to the ideal case of inviscid fluids. The methodology to obtain the marginal stability curves developed here is applicable to any arbitrary but time periodic signal, as demonstrated for the case of a signal with two different frequencies, and four different frequencies with a dc offset. The mode coupling in the interfacial normal stress leads to appearance of harmonic and subharmonic modes, characterized by the frequency of the oscillating interface at an integral or half-integral multiple of the applied frequency, respectively. This is in contrast to the application of a voltage with a single frequency which always leads to a harmonic mode oscillation of the interface. Whether a harmonic or subharmonic mode is the most unstable one depends on details of the excitation signal.

  2. Small Signal Stability Improvement of Power Systems Using Optimal Load Responses in Competitive Electricity Markets

    DEFF Research Database (Denmark)

    Hu, Weihao; Su, Chi; Chen, Zhe

    2011-01-01

    Since the hourly spot market price is available one day ahead in Denmark, the price could be transferred to the consumers and they may shift some of their loads from high price periods to the low price periods in order to save their energy costs. The optimal load response to an electricity price...... price is proposed. A 17-bus power system with high wind power penetrations, which resembles the Eastern Danish power system, is chosen as the study case. Simulation results show that the optimal load response to electricity prices is an effective measure to improve the small signal stability of power...

  3. Description and operating performance of a parallel-rail electric-arc system with helium driver gas for the Langley 6-inch expansion tube

    Science.gov (United States)

    Moore, J. A.

    1976-01-01

    A parallel-rail arc-discharge system to heat and pressurize the initial helium driver gas of the Langley 6-inch expansion tube is described. This system was designed for a 2.44-m-long driver vessel rated at 138 MPa, with a distance between rails of 20.3 cm. Electric energy was obtained from a capacitor storage system rated at 12,000 V with a maximum energy of 5 MJ. Tests were performed over a range of energy from 1.74 MJ to the maximum value. The operating experience and system performance are discussed, along with results from a limited number of expansion-tube tests with air and carbon dioxide as test gases.

  4. The effect of smelting time and composition of palm kernel shell charcoal reductant toward extractive Pomalaa nickel laterite ore in mini electric arc furnace

    Science.gov (United States)

    Sihotang, Iqbal Huda; Supriyatna, Yayat Iman; Ismail, Ika; Sulistijono

    2018-04-01

    Indonesia is a country that is rich in natural resources. Being a third country which has a nickel laterite ore in the world after New Caledonia and Philippines. However, the processing of nickel laterite ore to increase its levels in Indonesia is still lacking. In the processing of nickel laterite ore into metal, it can be processed by pyrometallurgy method that typically use coal as a reductant. However, coal is a non-renewable energy and have high enough levels of pollution. One potentially replace is the biomass, that is a renewable energy. Palm kernel shell are biomass that can be used as a reductant because it has a fairly high fix carbon content. This research aims to make nickel laterite ores become metal using palm kernel shell charcoal as reductant in mini electric arc furnace. The result show that the best smelting time of this research is 60 minutes with the best composition of the reductant is 2,000 gram.

  5. Energy efficiency and the influence of gas burners to the energy related carbon dioxide emissions of electric arc furnaces in steel industry

    International Nuclear Information System (INIS)

    Kirschen, Marcus; Risonarta, Victor; Pfeifer, Herbert

    2009-01-01

    Determining the complete energy balance of an electric arc furnace (EAF) provides an appropriate method to examine energy efficiency and identify energy saving potentials. However, the EAF energy balance is complex due to the combined input of electrical energy and chemical energy resulting from natural gas (NG) combustion and oxidation reactions in the steel melt. In addition, furnace off-gas measurements and slag analysis are necessary to reliably determine energy sinks. In this paper 70 energy balances and energy efficiencies from multiple EAFs are presented, including data calculated from plant measurements and compiled from the literature. Potential errors that can be incorporated in these calculations are also highlighted. The total energy requirement of these modern EAFs analysed ranged from 510 to 880 kWh/t, with energy efficiency values (η = ΔH Steel /E Total ) of between 40% and 75%. Furthermore, the focus was placed on the total energy related CO 2 emissions of EAF processes comprising NG combustion and electrical energy input. By assessing multiple EAF energy balances, a significant correlation between the total energy requirement and energy related specific CO 2 emissions was not evident. Whilst the specific consumption of NG in the EAF only had a minor impact on the EAF energy efficiency, it decreased the specific electrical energy requirement and increased EAF productivity where transformer power was restricted. The analysis also demonstrated that complementing and substituting electrical energy with NG was beneficial in reducing the total energy related CO 2 emissions when a certain level of substitution efficiency was achieved. Therefore, the appropriate use of NG burners in modern EAFs can result in an increased EAF energy intensity, whilst the total energy related CO 2 emissions remain constant or are even decreased.

  6. Stability of silver nanowire based electrodes under environmental and electrical stresses

    Science.gov (United States)

    Mayousse, Céline; Celle, Caroline; Fraczkiewicz, Alexandra; Simonato, Jean-Pierre

    2015-01-01

    Flexible transparent electrodes fabricated with random networks of silver nanowires (AgNWs) have been widely studied in recent years. This approach appears to be a promising alternative to replace ITO (indium tin oxide) in many optoelectronic applications. Many successful integrations in functional devices have already evidenced the high potential of this technology, but unfortunately only very few studies have been dedicated so far to the stability of this material. We present here a study dealing with the alteration of the electrical properties of AgNW meshes when subjected to different stresses. We demonstrate that AgNW electrodes are very stable when stored under ambient atmosphere up to, at least, two and a half years. Accelerated ageing processes also reveal that concentrated H2S or exposure to light does not cause any significant sheet resistance modification. However, the combination of high relative humidity and high temperature seems to be more critical. In addition, long lasting contact (two years) with PEDOT:PSS can induce deterioration of the electrical properties. Similarly, AgNW/PEDOT:PSS hybrid materials exhibit weaker stability under electrical stress when compared to pristine AgNW networks.Flexible transparent electrodes fabricated with random networks of silver nanowires (AgNWs) have been widely studied in recent years. This approach appears to be a promising alternative to replace ITO (indium tin oxide) in many optoelectronic applications. Many successful integrations in functional devices have already evidenced the high potential of this technology, but unfortunately only very few studies have been dedicated so far to the stability of this material. We present here a study dealing with the alteration of the electrical properties of AgNW meshes when subjected to different stresses. We demonstrate that AgNW electrodes are very stable when stored under ambient atmosphere up to, at least, two and a half years. Accelerated ageing processes also

  7. Stability of Electrical Characteristics of MOS Structures Based on Gallium Oxide

    Science.gov (United States)

    Kalygina, V. M.; Petrova, Yu. S.; Prudaev, I. A.; Tolbanov, O. P.

    2016-10-01

    We present the results of studying the capacitance-voltage and conductance-voltage characteristics of the GaxOy/ GaAs-based metal - oxide - semiconductor structures obtained by thermal evaporation. Influence of the annealing temperature on the characteristics of the structures is established. It is found that at long-term storage in the room atmosphere, the structures do not change their properties, which is manifested in the stability of electrical characteristics.

  8. Electrical properties and temperature stability of a new kind of lead-free piezoelectric ceramics

    International Nuclear Information System (INIS)

    Wang Yuanyu; Wu Jiagang; Xiao Dingquan; Zhang Bin; Wu Wenjuan; Shi Wei; Zhu Jianguo

    2008-01-01

    0.995[(K 0.50 Na 0.50 ) 0.94 Li 0.06 ]NbO 3 -0.005AETiO 3 (AE=Ca, Sr, Mg, Ba) lead-free piezoelectric ceramics were prepared by normal sintering. The effects of the AETiO 3 and poling temperature on the electrical properties of the ceramics were carefully studied, and the temperature stability of the electrical properties of the ceramics was also investigated. The experimental results show that the ceramics with Li and CaTiO 3 possess the pure phase, Li and AETiO 3 improves the electrical properties of the pure (K 0.50 Na 0.50 )NbO 3 ceramics, the poling temperature near tetragonal and orthorhombic phase transition will enhance the piezoelectric properties of the ceramics and the KNLN-CT ceramics exhibit good temperature stability of electrical properties for tetragonal and orthorhombic phase transition below room temperature. The KNLN-CT ceramics exhibit relatively good properties: d 33 = 172 pC N -1 , k p = 0.43, tan δ = 0.032, ε r = 771 and T c = 465 deg. C. As a result, the KNLN-CT ceramic is promising candidate material for piezoelectric devices.

  9. Effect of AC electric fields on the stabilization of premixed bunsen flames

    KAUST Repository

    Kim, Minkuk

    2011-01-01

    The stabilization characteristics of laminar premixed bunsen flames have been investigated experimentally for stoichiometric methane-air mixture by applying AC voltage to the nozzle with the single-electrode configuration. The detachment velocity either at blowoff or partial-detachment has been measured by varying the applied voltage and frequency of AC. The result showed that the detachment velocity increased with the applied AC electric fields, such that the flame could be nozzle-attached even over five times of the blowoff velocity without having electric fields. There existed four distinct regimes depending on applied AC voltage and frequency. In the low voltage regime, the threshold condition of AC electric fields was identified, below which the effect of electric fields on the detachment velocity is minimal. In the moderate voltage regime, the flame base oscillated with the frequency synchronized to AC frequency and the detachment velocity increased linearly with the applied AC voltage and nonlinearly with the frequency. In the high voltage regime, two different sub-regimes depending on AC frequency were observed. For relatively low frequency, the flame base oscillated with the applied AC frequency together with the half frequency and the variation of the detachment velocity was insensitive to the applied voltage. For relatively high frequency, the stabilization of the flame was significantly affected by the generation of streamers and the detachment velocity decreased with the applied voltage. © 2010 Published by Elsevier Inc. on behalf of The Combustion Institute. All rights reserved.

  10. Transient stability enhancement of electric power generating systems by 120-degree phase rotation

    Science.gov (United States)

    Cresap, Richard L.; Taylor, Carson W.; Kreipe, Michael J.

    1982-01-01

    A method and system for enhancing the transient stability of an intertied three-phase electric power generating system. A set of power exporting generators (10) is connected to a set of power importing generators (20). When a transient cannot be controlled by conventional stability controls, and imminent loss of synchronism is detected (such as when the equivalent rotor angle difference between the two generator sets exceeds a predetermined value, such as 150 degrees), the intertie is disconnected by circuit breakers. Then a switch (30) having a 120-degree phase rotation, or a circuit breaker having a 120-degree phase rotation is placed in the intertie. The intertie is then reconnected. This results in a 120-degree reduction in the equivalent rotor angle difference between the two generator sets, making the system more stable and allowing more time for the conventional controls to stabilize the transient.

  11. The roots of the Swiss hydroelectric success: the electric lighting introduction in the Lemanic arc (1881-1891)

    International Nuclear Information System (INIS)

    Humair, Cedric

    2005-01-01

    The development of a Swiss electro-technology industry was based on the rapid transfer of the Edison model associating one central power plant to electricity distribution through lighting. Market dynamism allowed Switzerland to take the lead in the European countries. But such a success can be explained only by engineers' skills, notably in the hydraulic field, as well as by the quality of the social networks. Indeed, political leaders had to put all their weight behind it to overcome reluctance shown by gas companies. Technically speaking, mastering pressure water networks will favour the increasing use of electricity. And in the tourism industry, electricity found a market that turned out to be immediately profitable

  12. Evaluation of recycled MgO-C bricks and dead-burned dolomite fines in setting slag foaming in the electric arc furnace

    Directory of Open Access Journals (Sweden)

    Thiago da Costa Avelar

    Full Text Available Abstract Production cost reduction for the Electric Arc Furnace (EAF technology is strongly dependent on the efficiency of the electrical energy being introduced into the metal bath. Besides EAF technology, the slag foaming process is currently applied to some other equipment for steel production aiming to save energy, productivity improvements, enhance the refractory service life and inhibit steel re-oxidation. In this way, this study involved the recycling options of Crushed MgO-C spent refractories removed from the EAF without complex and costly beneficiation, with emphasis on its application as a slag conditioner, since its composition presents high MgO content. The experiments were performed in a laboratory induction furnace and the temperature was controlled at 1700°C.The initial height of the slag was recorded and foaming briquettes added into the furnace. The experiments were carried out for 30 minutes. When the foaming process was finalized, an aliquot from the slag was collected to be analyzed by chemical analysis. Then, the metal with slag was tapped into a mold. The results indicated that the best viscosity was 0.39poise. The maximum height of foam formation was observed for a binary basicity greater than 1.2. The concentration of MgO in the slag is close to the saturation point.

  13. Proposition of a modification to the VAR process and its application in the consolidation of pressed zircaloy chips and the evaluation of the dynamical system of the electric arc

    International Nuclear Information System (INIS)

    Mucsi, Cristiano Stefano

    2005-01-01

    The objective of this work is the investigation of a new process as an alternative to the Vacuum Arc Remelting technology in the consolidation of Zircaloy chips. A procedure is proposed for the recycling of primary Zircaloy scraps by means of a modified VAR furnace. The performed studies were made in order to optimise the low cost new devices added to existing VAR furnace prototype, find ideal operational conditions, evaluate data acquisition system and the electric arc dynamical system in order to made viable the automated control of the modified VAR prototype. A funnel-crucible special device was developed and installed in a VAR prototype furnace allowing ingots to be obtained from pressed chips. This indicated the viability of creation of a new process for the consolidation of Zircaloy chips. The voltage of the electric arc during the melting runs was digitally recorded allowing the evaluation of the electric arc dynamics by using the topological invariant of the system: correlation dimension and the higher Liapunov exponent. (author)

  14. Concurrent temporal stability of the apparent electrical conductivity and soil water content

    Science.gov (United States)

    Pedrera-Parrilla, Aura; Pachepsky, Yakov A.; Taguas, Encarnación V.; Martos-Rosillo, Sergio; Giráldez, Juan V.; Vanderlinden, Karl

    2017-01-01

    Knowledge of spatio-temporal soil-water content (SWC) variability in agricultural fields is useful for improving crop management. Spatial patterns of SWC can be characterized using temporal stability analysis of difficult-to-obtain data from high spatial density and temporal frequency. Soil apparent electrical conductivity (ECa) measurements with high spatial density have been widely used to infer the spatial variability of SWC. The objective of this work is to test the hypothesis that temporal stability of ECa can be demonstrated and that relationships between temporal stability characteristics of SWC and ECa can be established. Apparent electrical conductivity and topsoil gravimetric SWC (θ) were periodically measured in an olive orchard in southwest Spain on 6 and 18 occasions, respectively. A temporal stability analysis of ECa elucidated three zones where ECa was close to, consistently substantially smaller than, and substantially larger than the spatial average ECa throughout the study period. Representative locations for θ were found with a chance of 75% within the representative zone for ECa. Yet, the driest locations, with consistently smaller θ than the field average (〈 θ 〉), could be successfully identified (89%) within the zone with consistently smaller ECa than average. The θ - 〈 θ 〉 relations showed generally a linear behaviour, although a better fit was obtained at the highest θ using either exponential or power law equations at half of the locations. The former provided the best fit within the zone with ECa consistently smaller than average, while the latter performed best in the zone with ECa consistently larger than average. The linear equation provided the best fit within the representative ECa zone. This study demonstrates that temporal stability characteristics of ECa and SWC are linked and that ECa surveys can be used to delimit zones with representative locations for SWC measurement or estimation. Such information is of

  15. Influence of configuration and operating conditions on the electric arc instabilities of a plasma spray torch: role of acoustic resonance

    International Nuclear Information System (INIS)

    Coudert, J F; Rat, V

    2008-01-01

    A theoretical approach is proposed to explain the particularities of the power spectrum of a plasma spray torch voltage. This is founded on an acoustic resonance of the rear part of the plasma torch which is occupied by the cold gas before it reaches the arc region. The spectrum is characterized by the presence of a sharp peak in the range 3-8 kHz, with an amplitude that represents up to ±30% of the voltage mean value. The peak frequency presents an evolution that is governed by the torch operating conditions, the thermal properties of the plasma forming gas and the geometrical configuration of the electrode assembly. The theory is compared with experimental values of the peak frequency recorded for different operating conditions and torch configurations. The injection ring through which the gas is injected also plays an important role. The torch behaviour is carefully characterized in order to collect all the experimental data required for the analysis on the involved phenomena.

  16. Impact of pulsed-electric field and high-voltage electrical discharges on red wine microbial stabilization and quality characteristics.

    Science.gov (United States)

    Delsart, C; Grimi, N; Boussetta, N; Miot Sertier, C; Ghidossi, R; Vorobiev, E; Mietton Peuchot, M

    2016-01-01

    In this study, pulsed-electric fields (PEF) and high-voltage electrical discharges (HVED) are proposed as new techniques for the microbial stabilization of red wines before bottling. The efficiency of the treatment was then evaluated. PEF and HVED-treatments have been applied to wine for the inactivation of Oenococcus oeni CRBO 9304, O. oeni CRBO 0608, Pediococcus parvulus CRBO 2.6 and Brettanomyces bruxellensis CB28. Different treatment times (1, 2, 4, 6, 8 and 10 ms) were used at 20 kV cm(-1) for the PEF treatments and at 40 kV for the HVED treatments, which correspond to applied energies from 80 to 800 kJ l(-1) . The effects of the treatments on the microbial inactivation rate and on various characteristics of red wines (phenolic composition, chromatic characteristics and physico-chemical parameters) were measured. The application of PEF or HVED treatments on red wine allowed the inactivation of alteration yeasts (B. bruxellensis CB28) and bacteria (O. oeni CRBO 9304, O. oeni CRBO 0608 and P. parvulus CRBO 2.6). The electric discharges at 40 kV were less effective than the PEF even after 10 ms of treatments. Indeed, 4 ms of PEF treatment at 20 kV cm(-1) were sufficient to inactivate all micro-organisms present in the wines. Also, the use of PEF had no negative impact on the composition of wines compared to the HVED treatments. Contrary to PEF, the phenolics compounds were degraded after the HVED treatment and the physico-chemical composition of wine were modified with HVED. PEF technology seems to be an interesting alternative to stabilize microbiologically wines before bottling and without modifying their composition. This process offers many advantages for winemakers: no chemical inputs, low energy consumption (320 kJ l(-1) ), fast (treatment time of 4 ms) and athermal (ΔT ≈ 10°C). © 2015 The Society for Applied Microbiology.

  17. Study of effect of electric arc furnace slag on expansion of mortars subjected to alkali-aggregate reaction

    Directory of Open Access Journals (Sweden)

    L. SOUZA

    Full Text Available Abstract Alkali-aggregate reaction is a chemical reaction between cement alkalis and some reactive mineral present in some aggregates, leading to concrete expansion and cracking. One kind usually observed and studied in Brazil is the alkali-silica reaction, due to its fast development. There are several methods that are effective to control and mitigate this reaction, and one of them is the partial replacement of cement by mineral additions such as pozzolans like fly-ash, silica fume and slag. In this study, we propose the use of electrical steel slag as a partial replacement of cement, evaluating its effectiveness by NBR 15577:2008, employing different proportions as replacement. It seems that the electrical steel slag, despite its expansive behavior, has been effective in the control of the ASR.

  18. Printing inks of electroactive polymer PEDOT:PSS: The study of biocompatibility, stability, and electrical properties.

    Science.gov (United States)

    Stříteský, Stanislav; Marková, Aneta; Víteček, Jan; Šafaříková, Eva; Hrabal, Michal; Kubáč, Lubomír; Kubala, Lukáš; Weiter, Martin; Vala, Martin

    2018-04-01

    Biocompatibility tests and a study of the electrical properties of thin films prepared from six electroactive polymer ink formulations based on poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) were performed. The aim was to find a suitable formulation of PEDOT:PSS and conditions for preparing thin films in order to construct printed bioelectronic devices for biomedical applications. The stability and electrical properties of such films were tested on organic electrochemical transistor (OECT)-based sensor platforms and their biocompatibility was evaluated in assays with 3T3 fibroblasts and murine cardiomyocytes. It was found that the thin films prepared from inks without an additive or any thin film post-treatment provide limited conductivity and stability for use in biomedical applications. These properties were greatly improved by using ethylene glycol and thermal annealing. Addition or post-treatment by ethylene glycol in combination with thermal annealing provided thin films with electrical resistance and a stability sufficient to be used in sensing of animal cell physiology. These films coated with collagen IV showed good biocompatibility in the assay with 3T3 fibroblasts when compared to standard cell culture plastics. Selected films were then used in assays with murine cardiomyocytes. We observed that these cells were able to attach to the PEDOT:PSS films and form an active sensor element. Spontaneously beating clusters were formed, indicating a good physiological status for the cardiomyocyte cells. These results open the door to construction of cheap printed electronic devices for biointerfacing in biomedical applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1121-1128, 2018. © 2018 Wiley Periodicals, Inc.

  19. Microstructural densification and electrical performance of yttria stabilized zirconia SOCF (Solid Oxide Fuel Cell) electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Furtado, J.G. de M., E-mail: furtado@cepel.b [Centro de Pesquisas de Energia Eletrica (ELETROBRAS/CEPEL), Rio de Janeiro, RJ (Brazil); Silva, C.A. da; Miranda, P.E.V. de [Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Metalurgica e de Materiais

    2010-07-01

    The understanding of the mechanisms associated with densification and sintering of Yttria stabilized zirconia (YSZ), a main solid oxide fuel cell electrolyte, enables the improvement of its microstructure. The present work that has the objective to study the sintering and densification processes of polycrystalline nanostructured 8% mol YSZ (8YSZ), correlating the microstructural development with the electrical performance of the material. The sintering behaviors of nanocrystalline 8YSZ powders obtained by two different chemical synthesis techniques (glycine-nitrate combustion process and Pechini method) were studied based on sintering dilatometer method. X-ray diffraction and scanning electron microscopy were used in the microstructural characterization. Full-densified 8YSZ (98.8%) were obtained and it was found that the samples obtained by the Pechini's method showed a higher densification degree in the final stage of sintering and resulted in ceramics with higher final relative density and better electrical behavior. (author)

  20. Impact of Penetration Wind Turbines on Transient Stability in Sulbagsel Electrical Interconnection System

    Science.gov (United States)

    Nurtrimarini Karim, Andi; Mawar Said, Sri; Chaerah Gunadin, Indar; Darusman B, Mustadir

    2018-03-01

    This paper presents a rotor angle analysis when transient disturbance occurs when wind turbines enter the southern Sulawesi electrical interconnection system (Sulbagsel) both without and with the addition of a Power Stabilizer (PSS) control device. Time domain simulation (TDS) method is used to analyze the rotor angle deviation (δ) and rotor angle velocity (ω). A total of 44 buses, 47 lines, 6 transformers, 15 generators and 34 loads were modeled for analysis after the inclusion of large-scale wind turbines in the Sidrap and Jeneponto areas. The simulation and computation results show the addition of PSS devices to the system when transient disturbance occurs when the winds turbine entering the Sulbagsel electrical system is able to dampen and improve the rotor angle deviation (δ) and the rotor angle velocity (ω) towards better thus helping the system to continue operation at a new equilibrium point.

  1. Electrical conductivity and chemical stability of BaCe0·8−xAxGd0 ...

    Indian Academy of Sciences (India)

    ceramics exhibit an excellent chemical stability against boiling water. Indium is a suitable doping element to promote the sintering densification and to enhance both electrical conductivity and chemical stability of Gd-doped BaCeO3 at operating temperatures. Keywords. Perovskite; solid electrolyte; impedance spectroscopy; ...

  2. Metal-dielectric interfaces in gigascale electronics thermal and electrical stability

    CERN Document Server

    He, Ming

    2012-01-01

    Metal-dielectric interfaces are ubiquitous in modern electronics. As advanced gigascale electronic devices continue to shrink, the stability of these interfaces is becoming an increasingly important issue that has a profound impact on the operational reliability of these devices. In this book, the authors present the basic science underlying  the thermal and electrical stability of metal-dielectric interfaces and its relationship to the operation of advanced interconnect systems in gigascale electronics. Interface phenomena, including chemical reactions between metals and dielectrics, metallic-atom diffusion, and ion drift, are discussed based on fundamental physical and chemical principles. Schematic diagrams are provided throughout the book to illustrate  interface phenomena and the principles that govern them. Metal-Dielectric Interfaces in Gigascale Electronics  provides a unifying approach to the diverse and sometimes contradictory test results that are reported in the literature on metal-dielectric i...

  3. Fast densification and electrical conductivity of yttria-stabilized zirconia nanoceramics

    International Nuclear Information System (INIS)

    Li, Q.; Xia, T.; Liu, X.D.; Ma, X.F.; Meng, J.; Cao, X.Q.

    2007-01-01

    Nanocrystalline 8YSZ (8 mol% yttria stabilized zirconia) bulk samples with grain sizes of 20-30 nm were synthesized by Sol-Gel method and then densified under a high pressure of 4.5 GPa at 1273 K for 10 min. The method led to the densification of 8YSZ to a relative density higher than 92% without grain growth. Fourier transmission Raman spectroscopy suggested that 8YSZ underwent a phase transition from the cubic phase to a phase mixture (tetragonal plus a trace of monoclinic) after the densification, which decreased the electrical conductivity to a certain degree as concluded from the impedance spectroscopy

  4. Effect of Bismuth Oxide on the Microstructure and Electrical Conductivity of Yttria Stabilized Zirconia

    Directory of Open Access Journals (Sweden)

    Liwei Liu

    2016-03-01

    Full Text Available Bismuth oxide (Bi2O3-doped yttria-stabilized zirconia (YSZ were prepared via the solid state reaction method. X-ray diffraction and electron diffraction spectroscopy results indicate that doping with 2 mol% Bi2O3 and adding 10 mol% yttria result in a stable zirconia cubic phase. Adding Bi2O3 as a dopant increases the density of zirconia to above 96%, while reducing its normal sintering temperature by approximately 250 °C. Moreover, electrical impedance analyses show that adding Bi2O3 enhances the conductivity of zirconia, improving its capability as a solid electrolyte for intermediate or even lower temperatures.

  5. Double Arc Instability in the Solar Corona

    Energy Technology Data Exchange (ETDEWEB)

    Ishiguro, N.; Kusano, K., E-mail: n-ishiguro@isee.nagoya-u.ac.jp [Institute for Space-Earth Environmental Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601 Japan (Japan)

    2017-07-10

    The stability of the magnetic field in the solar corona is important for understanding the causes of solar eruptions. Although various scenarios have been suggested to date, the tether-cutting reconnection scenario proposed by Moore et al. is one of the widely accepted models to explain the onset process of solar eruptions. Although the tether-cutting reconnection scenario proposes that the sigmoidal field formed by internal reconnection is the magnetic field in the pre-eruptive state, the stability of the sigmoidal field has not yet been investigated quantitatively. In this paper, in order to elucidate the stability problem of the pre-eruptive state, we developed a simple numerical analysis in which the sigmoidal field is modeled by a double arc electric current loop and its stability is analyzed. As a result, we found that the double arc loop is more easily destabilized than the axisymmetric torus, and it becomes unstable even if the external field does not decay with altitude, which is in contrast to the axisymmetric torus instability. This suggests that tether-cutting reconnection may well work as the onset mechanism of solar eruptions, and if so, the critical condition for eruption under a certain geometry may be determined by a new type of instability rather than by the torus instability. Based on them, we propose a new type of instability called double arc instability (DAI). We discuss the critical conditions for DAI and derive a new parameter κ , defined as the product of the magnetic twist and the normalized flux of the tether-cutting reconnection.

  6. Au/Ti resistors used for Nb/Pb-alloy Josephson junctions. I. Electrical stability

    International Nuclear Information System (INIS)

    Murakami, M.; Alessandrini, E.I.; Kim, K.K.

    1984-01-01

    Bilayered Au/Ti films are very attractive for use as resistor materials of experimental Nb/Pb-alloy Josephson junction devices. In order to predict the electrical stability of the Au/Ti resistors during storage at room temperature, changes in microstructure and electrical resistivity of Ti and Au/Ti films during isothermal annealing at temperatures ranging from 298--473 K were studied using transmission electron microscopy, x-ray diffraction, and electrical measurements. Growth of Ti grains during annealing was observed in these films. The activation energy for the grain growth was determined to be 1.51 eV. Decreases in the sheet resistance measured at 4.2 K were observed at the early stages of isothermal annealing. By analyzing the annealing temperature dependence of rates of resistance changes, the activation energy of 1.49 eV was obtained. This energy value is very close to that obtained for the grain growth and, therefore, one of the main causes in the resistance decrease is believed to be due to the growth of Ti grains. Based on the present results, a model to predict the electrical resistance change for the Au/Ti films during storage at room temperature was established. The model predicted that change in the resistance can be significantly reduced by preannealing the resistors at an elevated temperature. The prediction was supported by the experiment and an excellent quantitative agreement between measured resistance values and those predicted by the model was obtained. Based on this model, the change was predicted to be -1.5% after about 3 years at room temperature, if the resistors were preannealed at 353 K for 10 h. This resistor stability is satisfactory for designing logic and memory circuits of Josephson devices, and it can be increased simply by preannealing for longer times at 353 K

  7. Effects of nuclear electromagnetic pulse (EMP) on synchronous stability of the electric power system

    International Nuclear Information System (INIS)

    Manweiler, R.W.

    1975-11-01

    The effects of a nuclear electromagnetic pulse (EMP) on the synchronous stability of the electric power transmission and distribution systems are evaluated. The various modes of coupling of EMP to the power system are briefly discussed, with particular emphasis on those perturbations affecting the synchronous stability of the transmission system. A brief review of the fundamental concepts of the stability problem is given, with a discussion of the general characteristics of transient analysis. A model is developed to represent single sets as well as repetitive sets of multiple faults on the distribution systems, as might be produced by EMP. The results of many numerical stability calculations are presented to illustrate the transmission system's response from different types of perturbations. The important parameters of both multiple and repetitive faults are studied, including the dependence of the response on the size of the perturbed area, the fault density, and the effective impedance between the fault location and the transmission system. Both major load reduction and the effect of the opening of tie lines at the time of perturbation are also studied. We conclude that there is a high probability that EMP can induce perturbations on the distribution networks causing a large portion of the transmission network in the perturbed area to lose synchronism. The result would be an immediate and massive power failure

  8. Stability boundaries analysis of electric power system with DC transmission based on differential-algebraic equation system

    OpenAIRE

    Susuki, Yoshihiko; Hikihara Takashi; Chiang, HD

    2004-01-01

    This paper discusses stability boundaries in an electric power system with dc transmission based on a differential-algebraic equation (DAE) system. The DAE system is derived to analyze transient stability of the ac/dc power system: the differential equation represents the dynamics of the generator and the dc transmission, and the algebraic equation the active and reactive power relationship between the ac system and the dc transmission. In this paper complete characterization of stability bou...

  9. Observation and interpretation of particle and electric field measurements inside and adjacent to an active auroral arc

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, C.W.; Kelley, M.C.

    1977-06-01

    A Javelin sounding rocket instrumented to measure electric fields, energetic particles, and suprathermal electrons was flown across an auroral display in the late expansion phase of a substorm. Four distinct regions of fields and particles were interpreted here in light of our present understanding of auroral dynamics.r of 10 and resemble fluxes mesured in the equatorial plane during the expansion phase. The hard fluxes in the equatorward zone are further energized and may act as a source for the outer radiation belt as inward convection further energizes them.

  10. The comparison of the structure and microhardness of the tool steel C90 and HS 6-5-2 remelted with the electric arc

    Directory of Open Access Journals (Sweden)

    A. Dziedzic

    2010-04-01

    Full Text Available The examination of the structure and microhardness of surface layer of C90 non-alloy steel and HS 6-5-2 high speed steel after electric arc treatment are presented in the paper. The comparison has been presented due to the similar content of the carbon in both steels. The structure of the remelted zone of the steel C90 before the conventional tempering consists of the cells, dendritic cells surrounded with the cementite, there is a plate martensite and retained austenite inside them, whereas the structure of the steel HS 6-5-2 is consistuted with cells, dendritic cells and dendrites surrounded with the eutectic system, inside of which there is a plate martensite and retained austenite. Such structure is characterized by the similar microhardness (790-800 HV0,065 and intensity of the tribiological wear. The tempering causes the decrease of the microhardness in non-alloy steel and the increase of the microhardness in high speed steel.

  11. On the distribution and bonding environment of Zn and Fe in glasses containing electric arc furnace dust: A μ-XAFS and μ-XRF study

    International Nuclear Information System (INIS)

    Pinakidou, F.; Katsikini, M.; Paloura, E.C.; Kavouras, P.; Kehagias, Th.; Komninou, Ph.; Karakostas, Th.; Erko, A.

    2007-01-01

    We apply synchrotron radiation assisted X-ray fluorescence (SR-XRF), SR-XRF mapping as well as micro- and conventional X-ray absorption fine structure (μ-XAFS and XAFS) spectroscopies in order to study the bonding environment of Fe and Zn in vitrified samples that contain electric arc furnace dust from metal processing industries. The samples are studied in the as-cast state as well as after annealing at 900 deg. C. The SR-XRF results demonstrate that annealing does not induce any significant changes in the distribution of either Fe or Zn, in both the as-cast and annealed glasses. The μ-XAFS spectra recorded at the Fe-K and Zn-K edges reveal that the structural role of both Fe and Zn remains unaffected by the annealing procedure. More specifically, Fe forms both FeO 6 and FeO 4 polyhedra, i.e. acts as an intermediate oxide while Zn occupies tetrahedral sites

  12. Study on the Fluid Flow Characteristics of Coherent Jets with CO2 and O2 Mixed Injection in Electric Arc Furnace Steelmaking Processes

    Science.gov (United States)

    Wei, Guangsheng; Zhu, Rong; Wu, Xuetao; Yang, Lingzhi; Dong, Kai; Cheng, Ting; Tang, Tianping

    2018-03-01

    As an efficient oxygen supplying technology, coherent jets are widely applied in electric arc furnace (EAF) steelmaking processes to strengthen chemical energy input, speed up smelting rhythm, and promote the uniformity of molten bath temperature and compositions. Recently, the coherent jet with CO2 and O2 mixed injection (COMI) was proposed and demonstrated great application potentiality in reducing the dust production in EAF steelmaking. In the present study, based on the eddy dissipation concept model, a computational fluid dynamics model of coherent jets with COMI was built with the overall and detailed chemical kinetic mechanisms (GRI-Mech 3.0). Compared with one-step combustion reaction, GRI-Mech 3.0 consists of 325 elementary reactions with 53 components and can predict more accurate results. The numerical simulation results were validated by the combustion experiment data. The jet behavior and the fluid flow characteristics of coherent jets with COMI under 298 K and 1700 K (25 °C and 1427 °C) were studied and the results showed that for coherent jets with COMI, the chemical effect of CO2 significantly weakened the shrouding combustion reactions of CH4 and the relative importance of the chemical effect of CO2 increases with CO2 concentration increasing. The potential core length of coherent jet decreases with the volume fraction of CO2 increasing. Moreover, it also can be found that the potential core length of coherent jets was prolonged with higher ambient temperature.

  13. Synthesis of TiO2 visible light catalysts with controllable crystalline phase and morphology from Ti-bearing electric arc furnace molten slag.

    Science.gov (United States)

    Li, Yang; Liu, Lulu; Guo, Min; Zhang, Mei

    2016-09-01

    TiO2 visible light catalysts with different crystalline phases and morphologies were synthesized from titanium-bearing electric arc furnace molten slag (Ti-bearing EAF slag) by using a simple acidolysis process. The effects of the pH of the HCl solution, liquid to solid ratio (RL/S, HCl solution to the residue ratio, mL/g) and acidolysis time on the micro-morphology and crystalline phase of as-prepared TiO2 photocatalysts were systematically investigated. The results indicated that with decreasing pH in the HCl solution and increasing RL/S, the crystalline phase and micro-morphology of the obtained TiO2 nanostructures tended to transform from anatase type TiO2 with spherical nanoparticle structures to rutile type TiO2 with needle-like nanorod structures. The acidolysis time had little influence on the crystalline phase but great impact on the size of the obtained TiO2. The growth mechanism of TiO2 from Ti-bearing EAF slag during the acidolysis process was also discussed. In addition, the influence of RL/S on the photocatalytic properties of the synthesized nanostructured TiO2 was studied. The results showed that the photodegradation efficiency for Rhodamine B solution could reach 91.00% in 120min when the RL/S was controlled at 50:1. Copyright © 2016. Published by Elsevier B.V.

  14. Effects of various surfactants on the dispersion stability and electrical conductivity of surface modified graphene

    Energy Technology Data Exchange (ETDEWEB)

    Uddin, Md. Elias [WCU Program, Department of BIN Fusion Technology, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Kuila, Tapas [Surface Engineering and Tribology, CSIR – Central Mechanical Engineering Research Institute, Durgapur 721 302 (India); Nayak, Ganesh Chandra [Department of Applied Chemistry, ISM Dhanbad, Dhanbad 826 004, Jharkhand (India); Kim, Nam Hoon [Department of Hydrogen and Fuel Cell Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Ku, Bon-Cheol [Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Dunsan-ri, Bongdong-eup, Wanju-gun, Jeollabuk-do 864-9 (Korea, Republic of); Lee, Joong Hee, E-mail: jhl@chonbuk.ac.kr [WCU Program, Department of BIN Fusion Technology, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Department of Hydrogen and Fuel Cell Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of)

    2013-06-15

    Highlights: ► Water dispersible graphene has been prepared using ionic and non-ionic surfactants. ► XPS and FTIR spectra analysis confirm surface modification and reduction of GO. ► The highest water dispersibility is observed in the graphene modified with of SDBS. ► The best properties of modified graphene is achieved with GO/surfactant ratio of two. -- Abstract: Ionic and non-ionic surfactant functionalized, water dispersible graphene were prepared to investigate the effects on the dispersion stability and electrical conductivity of graphene. In this study, sodium dodecyl benzene sulfonate (SDBS), sodium dodecyl sulfate and 4-(1,1,3,3-tetramethylbutyl) phenyl-polyethylene glycol (Triton X-100) were used as ionic and non-ionic surfactants. The effects of surfactant concentrations on the dispersibility and electrical conductivity of the surface modified graphene were investigated. The dispersion stability of SDBS functionalized graphene (SDBS-G) was found to be best in water at 1.5 mg ml{sup −1}. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analysis indicate that the presence of surfactants does not prevent the reduction of graphene oxide (GO). These measurements also demonstrated that the surfactants were present on the surface of graphene, resulting in the formation of functionalized graphene. The thickness of different functionalized graphene was measured by Atomic force microscopy and varied significantly with different surfactants. The thermal properties of the functionalized graphene were also found to be dependent on the nature of the surfactants. The electrical conductivity of SDBS-G (108 S m{sup −1}) was comparatively higher than SDS and Triton X-100 functionalized graphene.

  15. Effects of various surfactants on the dispersion stability and electrical conductivity of surface modified graphene

    International Nuclear Information System (INIS)

    Uddin, Md. Elias; Kuila, Tapas; Nayak, Ganesh Chandra; Kim, Nam Hoon; Ku, Bon-Cheol; Lee, Joong Hee

    2013-01-01

    Highlights: ► Water dispersible graphene has been prepared using ionic and non-ionic surfactants. ► XPS and FTIR spectra analysis confirm surface modification and reduction of GO. ► The highest water dispersibility is observed in the graphene modified with of SDBS. ► The best properties of modified graphene is achieved with GO/surfactant ratio of two. -- Abstract: Ionic and non-ionic surfactant functionalized, water dispersible graphene were prepared to investigate the effects on the dispersion stability and electrical conductivity of graphene. In this study, sodium dodecyl benzene sulfonate (SDBS), sodium dodecyl sulfate and 4-(1,1,3,3-tetramethylbutyl) phenyl-polyethylene glycol (Triton X-100) were used as ionic and non-ionic surfactants. The effects of surfactant concentrations on the dispersibility and electrical conductivity of the surface modified graphene were investigated. The dispersion stability of SDBS functionalized graphene (SDBS-G) was found to be best in water at 1.5 mg ml −1 . X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analysis indicate that the presence of surfactants does not prevent the reduction of graphene oxide (GO). These measurements also demonstrated that the surfactants were present on the surface of graphene, resulting in the formation of functionalized graphene. The thickness of different functionalized graphene was measured by Atomic force microscopy and varied significantly with different surfactants. The thermal properties of the functionalized graphene were also found to be dependent on the nature of the surfactants. The electrical conductivity of SDBS-G (108 S m −1 ) was comparatively higher than SDS and Triton X-100 functionalized graphene

  16. An SEM Analysis of Bearing Failure Due to Electrical Arcing (Analyse par Microscopie Electronique a Balayage de l’Endommagement d’un Roulement a Billes a la Suite de Decharges Electriques Internes).

    Science.gov (United States)

    1983-01-01

    ANALYSIS OF BEARING FAILURE DUE TO ELECTRICAL ARCING ANALYSE PAR MICROSCOPIE ELECTRONIQUE A BALAYAGE DE L’ENIDOMMAGEMENT D’UN ROULEMENT A BILLES A LA SUITE...cause of subsequent fatigue and other mechanical damage to these components. RESUME Une analyse par microscopie 6lectronique A balayage a permis de...6vidence a la surface des billes de roulements et des voies de glissement par microscopie 6lectronique i balayage . Cela sugg~re que des d~charges

  17. dc Arc Fault Effect on Hybrid ac/dc Microgrid

    Science.gov (United States)

    Fatima, Zahra

    The advent of distributed energy resources (DER) and reliability and stability problems of the conventional grid system has given rise to the wide spread deployment of microgrids. Microgrids provide many advantages by incorporating renewable energy sources and increasing the reliability of the grid by isolating from the main grid in case of an outage. AC microgrids have been installed all over the world, but dc microgrids have been gaining interest due to the advantages they provide over ac microgrids. However the entire power network backbone is still ac and dc microgrids require expensive converters to connect to the ac power network. As a result hybrid ac/dc microgrids are gaining more attention as it combines the advantages of both ac and dc microgrids such as direct integration of ac and dc systems with minimum number of conversions which increases the efficiency by reducing energy losses. Although dc electric systems offer many advantages such as no synchronization and no reactive power, successful implementation of dc systems requires appropriate protection strategies. One unique protection challenge brought by the dc systems is dc arc faults. A dc arc fault is generated when there is a gap in the conductor due to insulation degradation and current is used to bridge the gap, resulting in an arc with very high temperature. Such a fault if it goes undetected and is not extinguished can cause damage to the entire system and cause fires. The purpose of the research is to study the effect of the dc arc fault at different locations in the hybrid ac/dc microgrid and provide insight on the reliability of the grid components when it is impacted by arc faults at various locations in the grid. The impact of dc arc fault at different locations on the performance of the PV array, wind generation, and constant power loads (CPL) interfaced with dc/dc converters is studied. MATLAB/Simulink is used to model the hybrid ac/dc microgrid and arc fault.

  18. APPROXIMATE CALCULATION OF ACTIVE RESISTANCE AND TEMPERATURE OF THE PULSE ELECTRIC ARC CHANNEL IN A HIGH-CURRENT DISCHARGE CIRCUIT OF A POWERFUL HIGH-VOLTAGE CAPACITOR ENERGY STORAGE

    Directory of Open Access Journals (Sweden)

    M.I. Baranov

    2017-08-01

    Full Text Available Purpose. To obtain calculation correlations for active resistance Rce and maximal temperature Tme of plasma channel of pulse electric arc in the air double-electrode system (DES with metal (graphite electrodes, and also practical approbation of the obtained correlations for Rce and Tme in the conditions of high-voltage laboratory on the powerful capacity energy storage (CES of electric setting, intended for reproducing on the electric loading of protracted C- component of current of artificial lightning with the USA rationed on normative documents by amplitude-temporal parameters (ATP. Methodology. Electrophysics bases of high-voltage impulse technique, scientific and technical bases of development and creation of high-voltage high-current impulse electrical equipment, including powerful CES, and also measuring methods in discharge circuits of powerful high-voltage CES of pulse currents of millisecond temporal range. Results. On the basis of engineering approach the new results of approximate calculation of values of Rce and Tme are resulted in the plasma channel of pulse electric arc discharge in air DES of atmospheric pressure with metallic (graphite electrodes. Practical approbation of results of calculation of values of Rce and Tme is executed as it applies to air DES, to connected in a discharge circuit of powerful high-voltage CES with protracted C- of component current of artificial lightning, characterized rationed ATP. It is shown that calculation of numeral value Rce approximately in 100 times exceeds the proper value of active resistance for the plasma channel of impulsive spark of electric discharge in air DES other things being equal, and a calculation of numeral value Tme well corresponds with the known thermodynamics information for classic electric arc in air DES of atmospheric pressure with graphite electrodes. Originality. New engineering approach is developed for the approximate calculation of values of Rce and Tme in electron

  19. Stability of electric characteristics of solar cells for continuous power supply

    Directory of Open Access Journals (Sweden)

    Stojanović Nebojša M.

    2015-01-01

    Full Text Available This paper investigates the output characteristics of photovoltaic solar cells working in hostile working conditions. Examined cells, produced by different innovative procedures, are available in the market. The goal was to investigate stability of electric characteristics of solar cells, which are used today in photovoltaic solar modules for charging rechargeable batteries which, coupled with batteries, supply various electronic systems such as radio repeaters on mountains tops, airplanes, mobile communication stations and other remote facilities. Charging of rechargeable batteries requires up to 25 % higher voltage compared to nominal output voltage of the battery. This paper presents results of research of solar cells, which also apply to cases in which continuous power supply is required. [Projekat Ministarstva nauke Republike Srbije, br. III 171007

  20. Improved electrical stability of CdS thin film transistors through Hydrogen-based thermal treatments

    KAUST Repository

    Salas Villaseñor, Ana L.

    2014-06-01

    Thin film transistors (TFTs) with a bottom-gate configuration were fabricated using a photolithography process with chemically bath deposited (CBD) cadmium sulfide (CdS) films as the active channel. Thermal annealing in hydrogen was used to improve electrical stability and performance of the resulting CdS TFTs. Hydrogen thermal treatments results in significant V T instability (V T shift) improvement while increasing the I on/I off ratio without degrading carrier mobility. It is demonstrated that after annealing V T shift and I on/I off improves from 10 V to 4.6 V and from 105 to 10 9, respectively. Carrier mobility remains in the order of 14.5 cm2 V s-1. The reduced V T shift and performance is attributed to a reduction in oxygen species in the CdS after hydrogen annealing, as evaluated by Fourier transform infrared spectroscopy (FTIR). © 2014 IOP Publishing Ltd.

  1. Paper-based silver-nanowire electronic circuits with outstanding electrical conductivity and extreme bending stability

    Science.gov (United States)

    Huang, Gui-Wen; Xiao, Hong-Mei; Fu, Shao-Yun

    2014-07-01

    Here a facile, green and efficient printing-filtration-press (PFP) technique is reported for room-temperature (RT) mass-production of low-cost, environmentally friendly, high performance paper-based electronic circuits. The as-prepared silver nanowires (Ag-NWs) are uniformly deposited at RT on a pre-printed paper substrate to form high quality circuits via vacuum filtration and pressing. The PFP circuit exhibits more excellent electrical property and bending stability compared with other flexible circuits made by existing techniques. Furthermore, practical applications of the PFP circuits are demonstrated.Here a facile, green and efficient printing-filtration-press (PFP) technique is reported for room-temperature (RT) mass-production of low-cost, environmentally friendly, high performance paper-based electronic circuits. The as-prepared silver nanowires (Ag-NWs) are uniformly deposited at RT on a pre-printed paper substrate to form high quality circuits via vacuum filtration and pressing. The PFP circuit exhibits more excellent electrical property and bending stability compared with other flexible circuits made by existing techniques. Furthermore, practical applications of the PFP circuits are demonstrated. Electronic supplementary information (ESI) available: Video of rolling tests; video of the PFP circuit used as flexible cable in a cell phone; video of the application of the circuit as a RFID tag; a detailed method for synthesizing silver nanowires; details of the PFP technique; folding tests for the circuits; air humidity test for the circuit. See DOI: 10.1039/c4nr00846d

  2. The electrical, elemental, optical, and surface properties of Si-doped ZnO thin films prepared by thermionic vacuum arc

    Science.gov (United States)

    Mohammadigharehbagh, Reza; Özen, Soner; Yudar, Hafizittin Hakan; Pat, Suat; Korkmaz, Şadan

    2017-09-01

    The purpose of this work is to study the properties of Si-doped ZnO (SZO) thin films, which were prepared using the non-reactive thermionic vacuum arc technique. The analysis of the elemental, optical, and surface properties of ZnO:Si thin films was carried out using energy dispersive x-ray spectroscopy, UV-VIS spectrophotometry, atomic force microscopy, and scanning electron microscopy, respectively. The current-voltage measurement was employed in order to study the electrical properties of the films. The effect of Si doping on the physical properties of ZnO films was investigated. The film thicknesses were measured as 55 and 35 nm for glass and PET substrates, respectively. It was clearly observed from the x-ray diffraction results that the Si and ZnO peaks were present in the coated SZO films for all samples. The morphological studies showed that the deposited surfaces are homogenous, dense, and have a uniform surface, with the existence of some cracks only on the glass substrate. The elemental composition has confirmed the existence of Zn, Si, and O elements within the prepared films. Using a UV-VIS spectrophotometer, the optical parameters such as transmittance, absorbance, refractive index, and reflectance were calculated. It should be noted that the transparency and refractive indices obtained from the measurements decrease with increasing Si concentration. The obtained optical bandgap values using transmittance spectra were determined to be 3.74 and 3.84 eV for the glass and PET substrates, respectively. An increase in the bandgap results demonstrates that the Si doping concentration is comparable to the pure ZnO thin films. The current versus voltage curves revealed the ohmic nature of the films. Subsequently, the development and fabrication of excellent transparent conducting electrodes enabled the appropriate use of Si-doped ZnO thin films.

  3. Effect of electric arc, gas oxygen torch and induction melting techniques on the marginal accuracy of cast base-metal and noble metal-ceramic crowns.

    Science.gov (United States)

    Gómez-Cogolludo, Pablo; Castillo-Oyagüe, Raquel; Lynch, Christopher D; Suárez-García, María-Jesús

    2013-09-01

    The aim of this study was to identify the most appropriate alloy composition and melting technique by evaluating the marginal accuracy of cast metal-ceramic crowns. Seventy standardised stainless-steel abutments were prepared to receive metal-ceramic crowns and were randomly divided into four alloy groups: Group 1: palladium-gold (Pd-Au), Group 2: nickel-chromium-titanium (Ni-Cr-Ti), Group 3: nickel-chromium (Ni-Cr) and Group 4: titanium (Ti). Groups 1, 2 and 3 were in turn subdivided to be melted and cast using: (a) gas oxygen torch and centrifugal casting machine (TC) or (b) induction and centrifugal casting machine (IC). Group 4 was melted and cast using electric arc and vacuum/pressure machine (EV). All of the metal-ceramic crowns were luted with glass-ionomer cement. The marginal fit was measured under an optical microscope before and after cementation using image analysis software. All data was subjected to two-way analysis of variance (ANOVA). Duncan's multiple range test was run for post-hoc comparisons. The Student's t-test was used to investigate the influence of cementation (α=0.05). Uncemented Pd-Au/TC samples achieved the best marginal adaptation, while the worst fit corresponded to the luted Ti/EV crowns. Pd-Au/TC, Ni-Cr and Ti restorations demonstrated significantly increased misfit after cementation. The Ni-Cr-Ti alloy was the most predictable in terms of differences in misfit when either torch or induction was applied before or after cementation. Cemented titanium crowns exceeded the clinically acceptable limit of 120μm. The combination of alloy composition, melting technique, casting method and luting process influences the vertical seal of cast metal-ceramic crowns. An accurate use of the gas oxygen torch may overcome the results attained with the induction system concerning the marginal adaptation of fixed dental prostheses. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. "Squishy capacitor" model for electrical double layers and the stability of charged interfaces.

    Science.gov (United States)

    Partenskii, Michael B; Jordan, Peter C

    2009-07-01

    Negative capacitance (NC), predicted by various electrical double layer (EDL) theories, is critically reviewed. Physically possible for individual components of the EDL, the compact or diffuse layer, it is strictly prohibited for the whole EDL or for an electrochemical cell with two electrodes. However, NC is allowed for the artificial conditions of sigma control, where an EDL is described by the equilibrium electric response of electrolyte to a field of fixed, and typically uniform, surface charge-density distributions, sigma. The contradiction is only apparent; in fact local sigma cannot be set independently, but is established by the equilibrium response to physically controllable variables, i.e., applied voltage phi (phi control) or total surface charge q (q control). NC predictions in studies based on sigma control signify potential instabilities and phase transitions for physically realizable conditions. Building on our previous study of phi control [M. B. Partenskii and P. C. Jordan, Phys. Rev. E 77, 061117 (2008)], here we analyze critical behavior under q control, clarifying the basic picture using an exactly solvable "squishy capacitor" toy model. We find that phi can change discontinuously in the presence of a lateral transition, specify stability conditions for an electrochemical cell, analyze the origin of the EDL's critical point in terms of compact and diffuse serial contributions, and discuss perspectives and challenges for theoretical studies not limited by sigma control.

  5. Study on Adaptive Slid Mode Controller for Improving Handling Stability of Motorized Electric Vehicles

    Directory of Open Access Journals (Sweden)

    LiQiang Jin

    2014-01-01

    Full Text Available An adaptive slid mode controller was established for improving the handling stability of motorized electric vehicle (MEV. First and foremost, the structure and advantages of electric vehicle driven by in-wheel motors will be provided. Then, an ideal cornering model of vehicles will be brought and analyzed, after which a method to estimate side-slip angle was also proposed and three typical sensors were used in the theory. Besides, an idea for the recognition of road adhesion coefficient was derived based on MEV platform, which will be helpful for better control performances. Finally, the scheme of control method was given and some typical tests for observing handling properties were implemented based on Simulink and Carsim software. With the outcomes from the experiments, which vividly showed the merits of the controller, one can come to a conclusion that MEV that equips with the adaptive slid mode controller always enjoys better handling performances than the one without control. Furthermore, the controller researched is friendly to the real-time working conditions, which will hold practical values in the future.

  6. Electrical conductivity and chemical stability of BaCe0· 8− xAxGd0 ...

    Indian Academy of Sciences (India)

    ... K. BaCe0.7In0.1Gd0.2O3− and BaCe0.7Zr0.1Gd0.2O3− ceramics exhibit an excellent chemical stability against boiling water. Indium is a suitable doping element to promote the sintering densification and to enhance both electrical conductivity and chemical stability of Gd-doped BaCeO3 at operating temperatures.

  7. OPTIMAL CONTROL SYSTEM FOR PRECISION ELECTRIC DRIVE WITH GUARANTEED DEGREE OF STABILITY

    Directory of Open Access Journals (Sweden)

    A. A. Abdullin

    2014-03-01

    Full Text Available Improved design method of optimal control system for the linear object with elastic coupling is considered. Standard optimal control system design implies the selection of state and input penalty matrix for the quadratic functional. Moreover the system performance quality depends greatly on the specific penalty matrix. Instead of the state and input penalty matrix selection procedure the selection of desired stability degree is proposed. The proposed method of optimal control system design is based on the idea of new state matrix utilization. The new state matrix has its eigenvalues at the specified distance to the right from the eigenvalues of the original state matrix. Thereupon we can assign the closed loop state feedback system matrix eigenvalues at that specified distance to the left from imaginary axis of the complex plane, in the other words, we can achieve the desired stability degree of the system. The proposed method of control algorithm design is demonstrated for a control system of an electric drive with two-mass mechanism (object. Object characteristic was evaluated by amplitudefrequency response obtained during identification experiment. Unavailable or immeasurable variables of the control object state were estimated by reduced-order observer while optimal control system design.

  8. Electrohydrostatic and electrohydrodynamic theories of equilibrium shapes and stability of electrically stressed conducting liquids

    International Nuclear Information System (INIS)

    Chung, M.S.

    1986-01-01

    This work represents an initial attempt at a systematic and rigorous study of the static and dynamic equilibrium shapes and stability of electrically stressed conducting fluids. The ultimate objective of the research is to explain the basic mechanism(s) describing the operation of a field emission liquid metal ion source. The variational procedure is used to obtain a set of equations whose solutions describe the static fluid shape as a function of applied field. Using an iterative procedure to solve Laplace's equation for an arbitrary geometry, a sequence of profiles is calculated that shows the evolution of the deformed fluid surface with applied field. A systematic study of stability is made by applying the Taylor and Zeleny criteria to quasi-statistically stressed fluids. To formulate a realistic and accurate description of the onset of instability, is is necessary to introduce fluid flow, which requires a dynamical analysis. To maintain contact with the LMIS configuration, the approach to instability is studied in axially symmetric fluids using a linearized set of electrohydrodynamic equations. The analysis is applied to different coordinate surfaces, which are used to model fluid shapes, which are observed, or assumed to exist, in an operating LMIS just prior to or at the onset of emission. Results suggest a new interpretation of the onset of instability

  9. Comportamiento del tiempo de duración, la frecuencia de los cortocircuitos y la conductividad eléctrica durante el reencendido del arco en la soldadura SMAW (AC con electrodos E6013 Behavior of short-circuit frequency and duration time and electrical conductivity on arc turn- on during SMAW (AC with E6013 electrodes

    Directory of Open Access Journals (Sweden)

    Alejandro García Rodríguez

    2009-03-01

    Full Text Available El presente trabajo tiene como objetivo la evaluación del comportamiento del tiempo de duración, la frecuencia de los cortocircuitos y la conductividad durante el reencendido del arco en el proceso de soldadura SMAW (Shielded Metal Arc Welding, con corriente alterna y electrodos E6013. El análisis estadístico no-paramétrico garantiza un procesamiento robusto de los datos, atenuando la influencia de valores atípicos y errores derivados del empleo de aproximaciones a distribuciones continuas conocidas. La mediana y la mediana de la desviación absoluta (MAD, respecto a la mediana de los datos, constituyen los estimadores de localización y dispersión utilizados, respectivamente. El electrodo, en el régimen de 160 A, presenta una mayor estabilidad, en el aporte metálico, dada por el menor valor del MAD promedio del período de cortocircuito (39,36 ms y de la duración del cortocircuito (1,43 ms, reafirmada con la presencia de una mayor conductividad eléctrica durante el reencendido (1766,17x10-3 S·s-1.The objective of this work is the valuation of the behavior of short-circuits frequency and duration time and electrical conductivity on arc reigniting in SMAW (Shielded Metal Arc Welding process with alternate current and E6013 electrodes. The non parametric statistic analysis realize a robust data processing, minimizing the outliers influence and mistakes derivates about employ of approximations to well know continues distributions. The median and the median absolute deviation (MAD respect to median of the data are the localization and dispersion estimators used, respectively. The electrode at 160 A present a better stability on metal transference supported on the most little value of MAD for the period of transference (39,36 ms, and the MAD of the short-circuit duration (1,43 ms, according with the presence of a major electric conductivity during the arc reigniting (1766,17x10-3 S·s-1.

  10. Analysis Of Functional Stability Of The Triphased Asynchronous Generator Used In Conversion Systems Of A Eolian Energy Into Electric Energy

    Directory of Open Access Journals (Sweden)

    Ion VONCILA

    2003-12-01

    Full Text Available This paper presents a study of the influence of the main perturbation agent over the functional stability of the triphased asynchronous generator (for the two alternative: with coiled and short circuit rotor, used for the conversion systems from a eolian energy into electric energy.

  11. The problem of ensuring the seismic stability of atomic electric power plant equipment and ways of solving it

    International Nuclear Information System (INIS)

    Kaznovskii; Filippov, G.A.

    1983-01-01

    By seismic stability the authors mean the ability of the equipment and buildings to retain certain properties when subjected to seismic loads: leakproofness, strength, the absence of any residual changes of shape, which interfere with normal operation, ability to be repaired, nuclear and radiation safety. The latter requirement is the main thing which differentiates atomic electric power plants from other constructions, including other power-generation plants. Whereas, for example, an accident in the event of an earthquake in a thermal electric power plant can be regarded as a local accident, and the measures to ensure seismic stability are determined by economic factors and safety requirements for the operating staff, to ensure the seismic stability of an AES it is essential to take account in the first instance of the possibility of dangerous radiation effects both in the AES and in the vast area around it

  12. A rotating arc plasma invertor

    International Nuclear Information System (INIS)

    Reusch, M.F.; Jayaram, K.

    1987-02-01

    A device is described for the inversion of direct current to alternating current. The main feature is the use of a rotating plasma arc in crossed electric and magnetic fields as a switch. This device may provide an economic alternative to other inversion methods in some circumstances

  13. In-depth investigation of high-energy arcing faults (HEAF) of electrical components with possible induced fires; Vertiefte Untersuchungen zum hochenergetischen Versagen elektrischer Komponenten (HEAF) mit moeglicher Brandfolge

    Energy Technology Data Exchange (ETDEWEB)

    Roewekamp, Marina

    2015-11-15

    Main objective of the project 3611R01301 performed on behalf of the Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB) is an in-depth investigation of fires at electrical components induced by high energy arcing faults (HEAF) according to their non-negligible significance to nuclear safety. This report provides an overview on the insights with respect to high energy arcing faults at electrical components mainly gained from investigations of the national as well as international operating experience from nuclear installations. Moreover, the insights from the international operating experience have resulted in an experimental program carried out in the frame of a task by the OECD Nuclear Energy Agency (NEA) in order to investigate failures of electrical components, e. g. breakers, switchgears or transformers, installed in nuclear power plants of the member countries due to HEAF and potential consequential fires. The results of the in-depth analyses and experimental investigations shall be used for identifying potential areas of damage in a suitable manner. The results based on inter-national research shall also be checked with respect to their applicability to the situation in German nuclear power plants.

  14. Electron beam position stabilization with a piezo-electric optical correction system

    CERN Document Server

    Averett, T; McKeown, R D; Pitt, M

    1999-01-01

    A piezo-electrically controlled optical correction system was successfully used to reduce the helicity-correlated pulse-to-pulse position differences of a laser spot to better than +-100 nm at a pulse rate of 600 Hz. Using a simple feedback algorithm, average position differences of DELTA x-bar=-3.5+-4.2 nm and DELTA y-bar=2.6+-6.6 nm were obtained over a 6 h period. This optical correction system was successfully used in the polarized electron source at the Bates Linear Accelerator Center to stabilize the position of the electron beam during the recent SAMPLE experiment. Because this experiment measures a parity violating signal at the 10 sup - sup 6 level, it is sensitive to systematic effects which are correlated with the helicity of the incident electrons. One potentially large systematic effect is the helicity-correlated motion of the incident electron beam. By using this optical correction system, electron beam position differences at the location of the experiment were routinely kept well below +-100 n...

  15. Assessing Short-Term Voltage Stability of Electric Power Systems by a Hierarchical Intelligent System.

    Science.gov (United States)

    Xu, Yan; Zhang, Rui; Zhao, Junhua; Dong, Zhao Yang; Wang, Dianhui; Yang, Hongming; Wong, Kit Po

    2016-08-01

    In the smart grid paradigm, growing integration of large-scale intermittent renewable energies has introduced significant uncertainties to the operations of an electric power system. This makes real-time dynamic security assessment (DSA) a necessity to enable enhanced situational-awareness against the risk of blackouts. Conventional DSA methods are mainly based on the time-domain simulation, which are insufficiently fast and knowledge-poor. In recent years, the intelligent system (IS) strategy has been identified as a promising approach to facilitate real-time DSA. While previous works mainly concentrate on the rotor angle stability, this paper focuses on another yet increasingly important dynamic insecurity phenomenon-the short-term voltage instability, which involves fast and complex load dynamics. The problem is modeled as a classification subproblem for transient voltage collapse and a prediction subproblem for unacceptable dynamic voltage deviation. A hierarchical IS is developed to address the two subproblems sequentially. The IS is based on ensemble learning of random-weights neural networks and is implemented in an offline training, a real-time application, and an online updating pattern. The simulation results on the New England 39-bus system verify its superiority in both learning speed and accuracy over some state-of-the-art learning algorithms.

  16. Electrical properties and mechanical stability of anchoring groups for single-molecule electronics

    Directory of Open Access Journals (Sweden)

    Riccardo Frisenda

    2015-07-01

    Full Text Available We report on an experimental investigation of transport through single molecules, trapped between two gold nano-electrodes fabricated with the mechanically controlled break junction (MCBJ technique. The four molecules studied share the same core structure, namely oligo(phenylene ethynylene (OPE3, while having different aurophilic anchoring groups: thiol (SAc, methyl sulfide (SMe, pyridyl (Py and amine (NH2. The focus of this paper is on the combined characterization of the electrical and mechanical properties determined by the anchoring groups. From conductance histograms we find that thiol anchored molecules provide the highest conductance; a single-level model fit to current–voltage characteristics suggests that SAc groups exhibit a higher electronic coupling to the electrodes, together with better level alignment than the other three groups. An analysis of the mechanical stability, recording the lifetime in a self-breaking method, shows that Py and SAc yield the most stable junctions while SMe form short-lived junctions. Density functional theory combined with non-equlibrium Green’s function calculations help in elucidating the experimental findings.

  17. Phase structures of the black Dp-D(p+4)-brane system in various ensembles II: electrical and thermodynamic stability

    International Nuclear Information System (INIS)

    Xiao, Zhiguang; Zhou, Da

    2015-01-01

    By incorporating the electrical stability condition into the discussion, we continue the study on the thermodynamic phase structures of the Dp-D(p+4) black brane in GG, GC, CG, CC ensembles defined in our previous paper http://dx.doi.org/10.1007/JHEP07(2015)134. We find that including the electrical stability conditions in addition to the thermal stability conditions does not modify the phase structure of the GG ensemble but puts more constraints on the parameter space where black branes can stably exist in GC, CG, CC ensembles. In particular, the van der Waals-like phase structure which was supposed to be present in these ensembles when only thermal stability condition is considered would no longer be visible, since the phase of the small black brane is unstable under electrical fluctuations. However, the symmetry of the phase structure by interchanging the two kinds of brane charges and potentials is still preserved, which is argued to be the result of T-duality.

  18. Role of arc mode in laser-metal active gas arc hybrid welding of mild steel

    International Nuclear Information System (INIS)

    Li, Geng; Zhang, Chen; Gao, Ming; Zeng, Xiaoyan

    2014-01-01

    Highlights: • Pulsed arc is more effective to improve the stability of laser-arc hybrid welding. • LCHW has the highest fraction of acicular ferrite and high-angle grain boundaries. • Grain refinement depends on effective current of the arc. • LSHW has the most apparent vestige of texture components. • The microstructure and microtexture formation mechanisms were summarized. - Abstract: Arc mode plays an important role in joint characterizations of arc welding, but it has been seldom considered in laser-arc hybrid welding. This paper investigated the role of arc mode on laser-metal active gas (MAG) arc hybrid welding of mild steel. Three arc modes were employed, which were cold metal transfer (CMT), pulsed spray arc and standard short circuiting arc. Microtexture of the joints were observed and measured via electron back scattering diffraction (EBSD) system to reveal the effect of arc mode on microstructure. Mechanical properties of the joints were evaluated by tensile and Charpy V-notch impact tests. It was found that both the stability and mechanical properties of laser-CMT hybrid welding (LCHW) is the best, while those of laser-standard short circuiting arc welding (LSHW) is the worst. OM and EBSD results showed that the fraction of acicular ferrite and high-angle grain boundaries in fusion zone decreases gradually in the sequence of LCHW, laser-pulsed spray arc welding and LSHW, while the mean grain size increases gradually. Finally, the microstructure formation mechanisms and the relationship between microstructure and mechanical properties were summarized by the loss of alloying element and the stirring effect in molten pool

  19. Stability of the Small Electric Vehicle with Two In-Wheel Motors

    Directory of Open Access Journals (Sweden)

    Heerwan P.M.

    2017-01-01

    Full Text Available For a small electric vehicle (EV with the rear two in-wheel motors, the hydraulic brake system and the mechanical brake system are installed at the front and rear tire respectively. The mechanical brake system is used at the rear tire because there is no enough space for the hydraulic brake system. In a braking condition, the in-wheel motor at the rear tire will generate the regenerative braking force and it can improve the braking performance of the vehicle. However, during braking on the low adhesion road surface, anti-lock brake system (ABS is very crucial to prevent the tire from lock-up. To improve the safety and stability of the vehicle, the combination of anti-skid control system and direct yaw moment control system is proposed. The anti-skid control system contains a hydraulic unit of ABS at the front tires and regenerative brake timing control at the rear tires. The control method of the regenerative brake timing control is same as ABS and it will turn on and off to prevent the tire from lock-up. On the other hand, the direct yaw moment control system is developed to increase the steer performance of the vehicle. The optimal control is used as the control strategy method to control the yaw moment. The simulation is developed in MATLAB Simulink and the result shows that the proposed model can improve the stopping distance from 9 seconds to 8.2 seconds. In addition, the combination of skid control and yaw moment control also improved the steer performance of the vehicle.

  20. Arc saw development report

    International Nuclear Information System (INIS)

    Deichelbohrer, P.R.; Beitel, G.A.

    1981-01-01

    The arc saw is one of the key components of the Contaminated Equipment Volume Reduction (CEVR) Program. This report describes the progress of the arc saw from its inception to its current developmental status. History of the arc saw and early contributors are discussed. Particular features of the arc saw and their advantages for CEVR are detailed. Development of the arc saw including theory of operation, pertinent experimental results, plans for the large arc saw and advanced control systems are covered. Associated topics such as potential applications for the arc saw and other arc saw installations in the world is also touched upon

  1. Effect of Sintering on the Properties of γ-Brass (Cu5Zn8) Nanoparticles Produced by the Electric Arc Discharge Method and the Thermal Conductivity of γ-Brass Oil-Based Nanofluid

    Science.gov (United States)

    Farbod, Mansoor; Mohammadian, Alireza; Ranjbar, Khalil; Kouhpeymani Asl, Razieh

    2016-03-01

    Cu5Zn8 nanoparticles with a mean particle size of 21 nm were produced using the electric arc discharge method at 1 atm pressure Ar and 300 A arc current. The effect of sintering on the properties of Cu5Zn8 nanoparticle pellets prepared by pressing nanopowders under 750 MPa pressure was studied. Particles grew uniformly when sintered at 1013 K (740 °C), as opposed to those samples that were unsintered, resulting in a reduction of pores and an increase in density of about 21 pct. The electrical resistivity and hardness of the samples were also highly reduced. The results showed that the cooling rate can affect the properties of the sintered samples. The oil-based nanofluids with 0.2 to 3 wt pct of Cu5Zn8 nanoparticles were prepared, and it was found that the thermal conductivity of nanofluids increased with an increase in the weight percent of nanoparticles up to 1 pct and decreased afterward. The highest increase in thermal conductivity of 6 pct was measured compared to the base fluid.

  2. Estimating the stability of electrical conductivity of filled polymers under the influence of negative temperatures

    Science.gov (United States)

    Minakova, N. N.; Ushakov, V. Ya.

    2017-12-01

    One of the key problems in modern materials technology is synthesis of materials for electrotechnical devices capable of operating under severe conditions. Electrical and power engineering, in particular, demands for electrically conductive composite materials operating at high and low temperatures, various mechanical loads, electric fields, etc. Chaotic arrangement of electrically conductive component in the matrix and its structural and geometrical inhomogeneity can increase the local electric and thermal energy flux densities up to critical values even when their average values remain moderate. Elastomers filled with technical carbon being a promising component for electrotechnical devices was chosen as an object of study.

  3. Stability, Transient Response, Control, and Safety of a High-Power Electric Grid for Turboelectric Propulsion of Aircraft

    Science.gov (United States)

    Armstrong, Michael; Ross, Christine; Phillips, Danny; Blackwelder, Mark

    2013-01-01

    This document contains the deliverables for the NASA Research and Technology for Aerospace Propulsion Systems (RTAPS) regarding the stability, transient response, control, and safety study for a high power cryogenic turboelectric distributed propulsion (TeDP) system. The objective of this research effort is to enumerate, characterize, and evaluate the critical issues facing the development of the N3-X concept aircraft. This includes the proposal of electrical grid architecture concepts and an evaluation of any needs for energy storage.

  4. Electrical insulation properties of RF-sputtered LiPON layers towards electrochemical stability of lithium batteries

    OpenAIRE

    Vieira, E. M. F.; Ribeiro, J. F.; Silva, Maria Manuela; Barradas, N. P.; Alves, E.; Alves, A.; Correia, M. R.; Gonçalves, L. M.

    2016-01-01

    Electrochemical stability, moderate ionic conductivity and low electronic conductivity make the lithium phosphorous oxynitride (LiPON) electrolyte suitable for micro and nanoscale lithium batteries. The electrical and electrochemical properties of thin-film electrolytes can seriously compromise full battery performance. Here, radio-frequency (RF)-sputtered LiPON thin films were fabricated in nitrogen plasma under different working pressure conditions. With a slight decrease in ...

  5. Behaviour of radionuclides during accidental melting of orphan sources in electric arc furnaces by means of C.F.D. gas flow modeling

    International Nuclear Information System (INIS)

    Penalva, I.; Damborenea, J.; Legarda, F.; Zuloaga, P.; Ordonez, M.; Serrano, I.

    2006-01-01

    The appearance of orphan sources in steelmaking facilities has become a fact nowadays. Radiation sources, hidden within the scrap, may come into the scrap yard and become part of the melting. As a result, dispersion of the radioactive material that makes up the source takes place throughout the facility. The University of the Basque Country (U.P.V.-E.H.U.), in collaboration with the Empresa Nacional de Residuos Radiactivos, S.A. (E.N.R.E.S.A.) and the Consejo de Seguridad Nuclear (C.S.N.), has carried out a Research Project to analyze this accidental melting of radioactive sources in electric arc furnaces (E.A.F.). The whole steelmaking process can be analyzed in several discrete phases. Radioactive sources that may be incorporated to this process will be exposed to the different critical conditions prevailing during each phase. In this sense, Computational Fluid Dynamics (C.F.D.) has been used in order to recreate such conditions and so, determine the characteristics of the dispersion of radioactivity. Two different situations have been studied in detail using C.F.D. techniques: thermal conditions around a scrap-basket that contains the source just before entering the furnace and the deposition of steelmaking dust containing 137 Cs on the inner surface of flue pipes. Before entering the furnace, scrap is usually placed inside a basket that remains above the furnace during some time. Once the furnace is open the scrap is dropped into the furnace to complete the loading process. C.F.D. techniques have been used to analyze the thermal conditions around the basket in order to assess the possibility of a break of the radioactive source hidden within the scrap, concluding that commercial sources will maintain their integrity during the whole loading process. On the other hand, after entering the furnace dispersion of the radioactive material will take place. Physical and chemical properties of the active elements (chemical form, composition, melting point, etc

  6. Real-time 3D stabilization of a super-resolution microscope using an electrically tunable lens.

    Science.gov (United States)

    Tafteh, Reza; Abraham, Libin; Seo, Denny; Lu, Henry Y; Gold, Michael R; Chou, Keng C

    2016-10-03

    Single-molecule localization microscopy (SMLM) has become an essential tool for examining a wide variety of biological structures and processes. However, the relatively long acquisition time makes SMLM prone to drift-induced artifacts. Here we report an optical design with an electrically tunable lens (ETL) that actively stabilizes a SMLM in three dimensions and nearly eliminates the mechanical drift (RMS ~0.7 nm lateral and ~2.7 nm axial). The bifocal design that employed fiducial markers on the coverslip was able to stabilize the sample regardless of the imaging depth. The effectiveness of the ETL was demonstrated by imaging endosomal transferrin receptors near the apical surface of B-lymphocytes at a depth of 8 µm. The drift-free images obtained with the stabilization system showed that the transferrin receptors were present in distinct but heterogeneous clusters with a bimodal size distribution. In contrast, the images obtained without the stabilization system showed a broader unimodal size distribution. Thus, this stabilization system enables a more accurate analysis of cluster topology. Additionally, this ETL-based stabilization system is cost-effective and can be integrated into existing microscopy systems.

  7. Production of Manual Metal Arc Welding Electrodes with Local Raw ...

    African Journals Online (AJOL)

    Manual arc welding using flux coated electrodes is carried out by producing an electric arc between the base metal and a flux covered metal electrode with electric current that depends on the type of electrode, material, welding position and the desired strength. The composition of flux coated electrodes is complex and a ...

  8. production of manual arc welding electrodes with local raw materials

    African Journals Online (AJOL)

    CHUKSSUCCESS 4 LOVE

    ABSTRACT. Manual arc welding using flux coated electrodes is carried out by producing an electric arc between the base metal and a flux covered metal electrode with electric current that depends on the type of electrode, material, welding position and the desired strength. The composition of flux coated electrodes is ...

  9. Observations of arcing in the ISX tokamak

    International Nuclear Information System (INIS)

    Mioduszewski, P.; Clausing, R.E.; Heatherly, L.

    1979-01-01

    Arcing has been proposed as a major source of metal impurities in tokamak plasmas. Arc tracks have been observed in the ISX tokamak on the limiter, the inner-wall surface, and on the samples from the surface analysis station. Linear as well as fern-like arc tracks have been observed. From optical and SEM analysis of the tracks, it was estimated that about 10 16 to 10 17 atoms were released per arc. To study the influence of arcing on the tokamak discharge, an experiment was set up to measure electrical and optical signals of arcing in situ. In well controlled tokamak discharges, arcing was observed only during the initial breakdown of the plasma and during the quenching phase at the end of the discharge. In disrupted discharges, each plasma disruption was accompanied by arcing. The pulse-length of one single unipolar arc was measured to be about 50 μs and the current amplitude was typically about 20 A

  10. Electric field control of thermal stability and magnetization switching in (Ga,Mn)As

    Science.gov (United States)

    Chiba, D.; Ono, T.; Matsukura, F.; Ohno, H.

    2013-09-01

    Magnetization switching induced by electric fields in the absence of external magnetic field has been demonstrated in a field effect structure with a (Ga,Mn)As layer having an in-plane magnetic anisotropy. The switching is related to the modulation of the in-plane magnetic anisotropy by electric fields. Reducing magnetic anisotropy energy height by electric fields, we observe stochastic magnetization switching.

  11. Communications and control for electric power systems: Power system stability applications of artificial neural networks

    Science.gov (United States)

    Toomarian, N.; Kirkham, Harold

    1994-01-01

    This report investigates the application of artificial neural networks to the problem of power system stability. The field of artificial intelligence, expert systems, and neural networks is reviewed. Power system operation is discussed with emphasis on stability considerations. Real-time system control has only recently been considered as applicable to stability, using conventional control methods. The report considers the use of artificial neural networks to improve the stability of the power system. The networks are considered as adjuncts and as replacements for existing controllers. The optimal kind of network to use as an adjunct to a generator exciter is discussed.

  12. Energy recuperation in fully electric vehicles subject to stability and drivability requirements

    NARCIS (Netherlands)

    Ólafsdóttir, J.M.; Lidberg, M.; Falcone, P.; Iersel, S. van; Jansen, S.T.H.

    2012-01-01

    This paper presents a combined control and estimation framework for energy recuperation in fully electric vehicles. We consider a fully electric powertrain, with a driven front axle operating on low friction road surfaces. Our objective is to find the blending of regenerative and friction braking

  13. Modeling the Structural-Thermal-Electrical Coupling in an Electrostatically Actuated MEMS Switch and Its Impact on the Switch Stability

    Directory of Open Access Journals (Sweden)

    Hassen M. Ouakad

    2013-01-01

    Full Text Available Modeling and analysis for the static behavior and collapse instabilities of a MEMS cantilever switch subjected to both electrical and thermal loadings are presented. The thermal loading forces can be as a result of a huge amount of switching contact of the microswitch. The model considers the microbeam as a continuous medium and the electric force as a nonlinear function of displacement and accounts for its fringing-field effect. The electric force is assumed to be distributed over specific lengths underneath the microbeam. A boundary-value solver is used to study the collapse instability, which brings the microbeam from its unstuck configuration to touch the substrate and gets stuck in the so-called pinned configuration. We have found negligible influence of the temperature on the static stability of the switch. We then investigate the effect of the thermal heating due to the current flow on the cantilever switch while it is in the on position (adhered position. We also found slight effect on the static stability of the switch.

  14. Control of radioactive waste-glass melters: Part 3, Glass electrical stability

    Energy Technology Data Exchange (ETDEWEB)

    Bickford, D F; Propst, R C; Plodinec, M J

    1988-01-01

    Pilot waste-glass melter operations have indicated a tendency for noble-metal fission-product accumulation on melter floors, which can lead to distortion of electric heating patterns, and decrease melter life. Changes in melter geometry are being considered in Japan, Germany, and the United States to permit draining of the noble metals to reduce their effects. Physical modeling of melter electrical patterns, electrode/waste-glass electrochemistry, and non-linear electrical behavior have been evaluated for typical waste-glass. Major melter design changes should not be necessary for the US Department of Energy's Defense Waste Processing Facility (DWPF). Top electrodes will not be significantly affected. Minor alterations in melter design, monitoring of electrical characteristics, and adjustment of bottom electrode currents can provide protection from shorting if noble metals accumulate. 31 refs., 4 figs., 4 tabs.

  15. On the stability of preferences and attitudes before and after experiencing an electric vehicle

    DEFF Research Database (Denmark)

    Jensen, Anders Fjendbo; Cherchi, Elisabetta; Mabit, Stefan Lindhard

    2013-01-01

    -wave stated preference experiment where data was collected before and after the respondents experienced an electric vehicle for three months. We estimate a hybrid choice model using jointly the stated choices before and after the test period. The results show that individual preferences change significantly......In this study, we investigate the extent to which experience affects individual preferences for specific electric vehicle characteristics, individual attitudes toward the environment, and the impact of the attitudes on the choice between an electric and a conventional vehicle. We use a two...... after a real experience with an electric vehicle in the household. In particular, there are major changes in the preference for driving range, top speed, fuel cost, battery life and charging in city centres and train stations. In line with other studies, we find that environmental concern has a positive...

  16. Arc fault detection system

    Science.gov (United States)

    Jha, K.N.

    1999-05-18

    An arc fault detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings located in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn opens an upstream circuit breaker located between the switchboard and a power supply to remove the supply of power to the switchboard. 1 fig.

  17. Investigation of the stability of electrical properties of reduced LiNbO3 crystals

    Science.gov (United States)

    Yatsenko, A. V.; Pritulenko, A. S.; Yagupov, S. V.; Sugak, D. Yu.; Sol'skii, I. M.

    2017-07-01

    The instability of the electrical properties of lithium niobate single crystals of congruent composition subjected to reducing thermochemical treatment has been investigated by impedance spectroscopy. It has been shown that the subsequent heating of the reduced lithium niobate samples in dry air up to 380 K or higher is accompanied by the progressive increase in their electric resistance, which is due to the oxidization of the crystal surface layers.

  18. Driven Motion and Instability of an Atmospheric Pressure Arc

    International Nuclear Information System (INIS)

    Max Karasik

    1999-01-01

    Atmospheric pressure arcs are used extensively in applications such as welding and metallurgy. However, comparatively little is known of the physics of such arcs in external magnetic fields and the mechanisms of the instabilities present. In order to address questions of equilibrium and stability of such arcs, an experimental arc furnace is constructed and operated in air with graphite cathode and steel anode at currents 100-250 A. The arc is diagnosed with a gated intensified camera and a collimated photodiode array, as well as fast voltage and current probes

  19. Driven Motion and Instability of an Atmospheric Pressure Arc

    Energy Technology Data Exchange (ETDEWEB)

    Max Karasik

    1999-12-01

    Atmospheric pressure arcs are used extensively in applications such as welding and metallurgy. However, comparatively little is known of the physics of such arcs in external magnetic fields and the mechanisms of the instabilities present. In order to address questions of equilibrium and stability of such arcs, an experimental arc furnace is constructed and operated in air with graphite cathode and steel anode at currents 100-250 A. The arc is diagnosed with a gated intensified camera and a collimated photodiode array, as well as fast voltage and current probes.

  20. Transport coefficients in copper vapor arc plasmas

    International Nuclear Information System (INIS)

    Rahal, A.M.; Rahhaoui, B.; Vacquie, S.

    1985-01-01

    The presence of copper vapors modifies the properties of arc discharges. The paper deals with a region not investigated earlier, where in the core of the positive column of very short or high current arcs there is a high copper concentration. At these values the relative losses take a greater part in the energy balance. Using the charged-charged collision integrals, the transport coefficients (axial temperature, thermal and electric conductivity, viscosity) of the plasma with higher copper vapor concentration are calculated as the function of the arc current intensity. (D.Gy.)

  1. Numerical modeling of transferred arc melting bath heating; Modelisation numerique du chauffage de bains par arc transfere

    Energy Technology Data Exchange (ETDEWEB)

    Bouvier, A. [Electricite de France, 77 - Moret sur Loing (France). Direction des Etudes et Recherches; Trenty, L.; Guillot, J.B. [Ecole Centrale de Paris, Laboratoire EM2C. CNRS, 92 - Chatenay-Malabry (France); Delalondre, C. [Electricite de France (EDF), 78 - Chatou (France). Direction des Etudes et Recherches

    1997-12-31

    This paper presents the modeling of a transferred electric arc inside a bath of melted metal. After a recall of the context of the study, the problem of the modeling, which involves magnetohydrodynamic coupling inside the arc and the bath, is described. The equations that govern the phenomena inside the arc and the bath are recalled and the approach used for the modeling of the anode region of the arc is explained using a 1-D sub-model. The conditions of connection between arc and bath calculations are explained and calculation results obtained with a 200 kW laboratory furnace geometry are presented. (J.S.) 8 refs.

  2. Producción de aceros al carbono en hornos de arco eléctrico en condiciones de mineral de manganeso. // Steel production in electric arc furnaces in the condition of use of manganese.

    Directory of Open Access Journals (Sweden)

    E. E. Navas Medina

    2007-05-01

    Full Text Available El presente trabajo constituye una segunda etapa de investigación relacionada con la producción de acero en hornos de arcoeléctrico con revestimiento básico en condiciones de utilización de mineral de manganeso como sustituto del ferromanganeso.En la investigación se caracteriza el acero producido utilizando el mineral de manganeso en dos variantes tecnológicasdiferentes y se determinan parámetros importantes, tales como la estructura del acero obtenido, la influencia de lacomposición química y la temperatura en la reducción del Mn. Adicionalmente, se determina la composición química de laescoria, su basicidad e influencia en el aprovechamiento del Mn del mineral, así como, lo que significa la sustitución delFeMn en la problemática medioambiental.Palabras claves: Producción de aceros al carbono, hornos de arco eléctricos, mineral de manganeso.______________________________________________________________________________Abstract:This present work constitutes the second stage of investigation in relation with the steel production bymeans of electric arc furnaces in the condition of use of manganese ores as a substitute of theferromanganese. In the investigation, the steel manufactured is analyzed the manganese ore in twodifferent technological variants and some important parameters are determined such as: the chemicalcomposition's structure of the steel, the influence of temperature in the reduction of Mn. Moreover, ananalysis of the chemical composition of the slag and the influence in the environmental is realized.Key words: Carbon steel production, electric arc furnaces, manganese mineral.

  3. Stabilization

    Directory of Open Access Journals (Sweden)

    Muhammad H. Al-Malack

    2016-07-01

    Full Text Available Fuel oil flyash (FFA produced in power and water desalination plants firing crude oils in the Kingdom of Saudi Arabia is being disposed in landfills, which increases the burden on the environment, therefore, FFA utilization must be encouraged. In the current research, the effect of adding FFA on the engineering properties of two indigenous soils, namely sand and marl, was investigated. FFA was added at concentrations of 5%, 10% and 15% to both soils with and without the addition of Portland cement. Mixtures of the stabilized soils were thoroughly evaluated using compaction, California Bearing Ratio (CBR, unconfined compressive strength (USC and durability tests. Results of these tests indicated that stabilized sand mixtures could not attain the ACI strength requirements. However, marl was found to satisfy the ACI strength requirement when only 5% of FFA was added together with 5% of cement. When the FFA was increased to 10% and 15%, the mixture’s strength was found to decrease to values below the ACI requirements. Results of the Toxicity Characteristics Leaching Procedure (TCLP, which was performed on samples that passed the ACI requirements, indicated that FFA must be cautiously used in soil stabilization.

  4. Electricity

    Indian Academy of Sciences (India)

    AC power generation, its transmission and distribution. The well known observations made by Oersted that an electric current produces a magnetic field led a number of researchers to investigate whether the converse was true i.e. whether electric current can be produced from a magnetic field. Michael Faraday of England ...

  5. Effect of Electric Field in the Stabilized Premixed Flame on Combustion Process Emissions

    Science.gov (United States)

    Otto, Krickis

    2017-10-01

    The effect of the AC and DC electrical field on combustion processes has been investigated by various researchers. The results of these experiments do not always correlate, due to different experiment conditions and experiment equipment variations. The observed effects of the electrical field impact on the combustion process depends on the applied voltage polarity, flame speed and combustion physics. During the experiment was defined that starting from 1000 V the ionic wind takes the effect on emissions in flue gases, flame shape and combustion instabilities. Simulation combustion process in hermetically sealed chamber with excess oxygen amount 3 % in flue gases showed that the positive effect of electrical field on emissions lies in region from 30 to 400 V. In aforementioned voltage range carbon monoxide emissions were reduced by 6 % and at the same time the nitrogen oxide emissions were increased by 3.5 %.

  6. EMTP based stability analysis of space station electric power system in a test bed environment

    Science.gov (United States)

    Dravid, Narayan V.; Kacpura, Thomas J.; Oconnor, Andrew M.

    1992-01-01

    The Space Station Freedom Electric Power System (EPS) will convert solar energy into electric energy and distribute the same using an 'all dc', Power Management and Distribution (PMAD) System. Power conditioning devices (dc to dc converters) are needed to interconnect parts of this system operating at different nominal voltage levels. Operation of such devices could generate under damped oscillations (instability) under certain conditions. Criteria for instability are examined and verified for a single device. Suggested extension of the criteria to a system operation is examined by using the EMTP model of the PMAD DC test bed. Wherever possible, data from the test bed is compared with the modeling results.

  7. Electrical Grid Stability Enhancement using Smart Home Frequency-response Grid -Friendly Appliance System

    Directory of Open Access Journals (Sweden)

    Muawiya A. Kaigama

    2016-03-01

    Full Text Available Load shedding is a powerful scheme used for corrective and preventive measures; corrective to restore system’s stability and preventive to avoid catastrophic failure. However, the affected end users are deprived of power supply absolutely with no choice. This paper presents the design, development, feasibility and merits of Frequency-response Grid -Friendly Appliance System (FRGFAS in a smart home. FRGFAS is a decentralized Adaptive Load Shaving(ALS device that supports grid’s system stability by sensing grid’s frequency deterioration level and turns ON/OFF loads accordingly. The FRGFAS permits end users to carry out load shaving at their scale of preference in smart homes via flexible demand responses and automates outdoor lighting to optimum operational hours. FRGFAS obviate load shedding by shaving loads whenever the system is in distress and reset loads supply to the normal state when it stabilizes, this Consequently increases the end user comfort zone and averts a blackout.

  8. Effects of electric field and Coriolis force on electrohydrodynamic stability of poorly conducting couple stress parallel fluid flow in a channel

    International Nuclear Information System (INIS)

    Shankar, B.M.; Rudraiah, N.

    2013-01-01

    The linear stability of electrohydrodynamic poorly conducting couple stress viscous parallel fluid flow in a channel is studied in the presence of a non-uniform transverse electric field and Coriolis force using energy method and supplemented with Galerkin Technique. The sufficient condition for stability is obtained for sufficiently small values of the Reynolds number, R e . From this condition we show that strengthening or weakening of the stability criterion is dictated by the values of the strength of electric field, the coefficient of couple stress fluid and independent of Taylor number. In particular, it is shown that the interaction of electric field with couple stress is more effective in stabilizing the poorly conducting couple stress fluid compared to that in an ordinary Newtonian viscous fluid. (author)

  9. New challenge for the Norwegian electric power market: A free market of power creates stability problems

    International Nuclear Information System (INIS)

    Gjengedal, T.; Rabbe, O.; Ongstad, E.; Uhlen, K.; Hauger, B.; Vormedal, L.; Lysheim, D.

    1997-01-01

    The article relates to problems of grid stability as a consequence of market-based power turnover. In combination with special hydrologic conditions, new approaches are formed concerning power production and transmission. Efficient counter-acting efforts must be initiated at an early stage for power system stabilization also concerning future innovations from the year of 2000. Examples on the development of systems of static magnetization and damping, problems concerning dampers, power grid testing, digital regulators, faults in high voltage 3-phase systems, and evaluation of measures of improvement are discussed. 10 figs

  10. Stability enhancement and fuel economy of the 4-wheel-drive hybrid electric vehicles by optimal tyre force distribution

    Science.gov (United States)

    Goodarzi, Avesta; Mohammadi, Masoud

    2014-04-01

    In this paper, vehicle stability control and fuel economy for a 4-wheel-drive hybrid vehicle are investigated. The integrated controller is designed within three layers. The first layer determines the total yaw moment and total lateral force made by using an optimal controller method to follow the desired dynamic behaviour of a vehicle. The second layer determines optimum tyre force distribution in order to optimise tyre usage and find out how the tyres should share longitudinal and lateral forces to achieve a target vehicle response under the assumption that all four wheels can be independently steered, driven, and braked. In the third layer, the active steering, wheel slip, and electrical motor torque controllers are designed. In the front axle, internal combustion engine (ICE) is coupled to an electric motor (EM). The control strategy has to determine the power distribution between ICE and EM to minimise fuel consumption and allowing the vehicle to be charge sustaining. Finally, simulations performed in MATLAB/SIMULINK environment show that the proposed structure could enhance the vehicle stability and fuel economy in different manoeuvres.

  11. Synchronously Tailoring Strain Sensitivity and Electrical Stability of Silicone Elastomer Composites by the Synergistic Effect of a Dual Conductive Network

    Directory of Open Access Journals (Sweden)

    Nanying Ning

    2016-03-01

    Full Text Available The use of conductive polymer composites (CPCs as strain sensors has been widely investigated. A wide range of strain sensitivities and high repeatability are vital for different applications of CPCs. In this study, the relations of the conductive filler network and the strain-sensing behavior and electrical stability under fatigue cycles were studied systematically for the first time based on the conductive polymethylvinylsiloxane (PMVS composites filled with both carbon nanotubes arrays (CNTAs and carbon black (CB. It was proved that the composites could be fabricated with large strain-sensing capability and a wide range of strain sensitivities by controlling the volume ratio of CNTA/CB and their amounts. Additionally, the CNTA/CB/PMVS composite with 3 vol % content of fillers showed high sensitivity (GF is 10 at 60% strain, high repeatability (the relative standard deviation (RSD of the max R/R0 value is 3.58%, and electrical stability under fatigue cycles (value range of R/R0 is 1.62 to 1.82 at the same time due to the synergistic effects of the dual conductive network of CNTAs and CB. This could not be achieved by relying on a single CNTA or CB conductive network. This study may provide guidance for the preparation of high performance CPCs for applications in strain sensors.

  12. On the mechanics and stability of micro-plates in electrically loaded MEMS devices

    NARCIS (Netherlands)

    Sajadi, B.

    2017-01-01

    In the last decades, Micro-Electro-Mechanical Systems (MEMS) have drawn immense attention due to their potential use in a wide variety of modern applications, including micro-mechanical sensors and actuators. MEMS are devices combining mechanical and electrical components between 1 and 100

  13. DC arc weld starter

    Science.gov (United States)

    Campiotti, Richard H.; Hopwood, James E.

    1990-01-01

    A system for starting an arc for welding uses three DC power supplies, a high voltage supply for initiating the arc, an intermediate voltage supply for sustaining the arc, and a low voltage welding supply directly connected across the gap after the high voltage supply is disconnected.

  14. The influence of surface functionalisation on the electrical properties and thermal stability of nanodiamonds

    Energy Technology Data Exchange (ETDEWEB)

    Welch, Joseph O; Li, Pei; Chaudhary, Aysha; Edgington, Robert; Jackman, Richard B., E-mail: r.jackman@ucl.ac.uk [London Centre for Nanotechnology and the Department of Electronic and Electrical Engineering, University College London, 17-19 Gordon Street, London WC1H 0AH (United Kingdom)

    2014-10-07

    Detonation nanodiamond (ND) has recently emerged as a useful new class of diamond material. However, to date there has been little investigation of the electrical properties of this material. Due to the nanoscale dimensions, the surface functionalisation of the individual ND is of particular importance to the characteristics of ND films. Here, hydrogen and oxygen termination of ND, verified using Fourier transform infrared spectroscopy, are shown to strongly influence the electronic properties of NDs. Hydrogen terminated ND exhibiting a far greater resilience to thermal decomposition when compared to the oxygen terminated NDs. Moreover, H-NDs also displayed so-called “surface conductivity,” a property displayed by hydrogen-terminated bulk diamond films, whilst O-NDs display properties high resistivity. These results indicate that under the correct conditions ND layers can display similar electrical properties to “bulk” diamond thin films.

  15. Electric-Hydraulic Interaction - Impact of Hydraulic Properties on Stability in Isolated Operation

    OpenAIRE

    Finvik, Jørgen Olsen

    2016-01-01

    The models for hydraulic systems found in standard Power System Analysis tools are often based on simplified mathematical models. These simplifications may lead to inaccurate representations of the dynamic behaviour of hydro power plants. The objective of this Master's thesis was to study hydraulic effects and their impact on the performance of a hydro power plant from an electrical engineering point of view. A model of Riksheim power plant in Sykkylven, Møre og Romsdal has been in implem...

  16. Application of Tabu Search to UPFC Stabilizer Adjustment at a Multi Machine Electric Power System

    OpenAIRE

    Hasan Fayazi Boroujeni; Babak Keyvani Boroujeni; Ahmad Memaripour; Meysam Eghtedari

    2012-01-01

    Unified Power Flow Controller (UPFC) is one of the most viable and important Flexible AC Transmission Systems (FACTS) devises. Application of UPFC in single machine and multi machine electric power systems has been investigated with different purposes such as power transfer capability, damping of Low Frequency Oscillations (LFO), voltage support and so forth. But, an important issue in UPFC applications is to find optimal parameters of UPFC controllers. This paper presents the application of ...

  17. Liquid-Arc/Spark-Excitation Atomic-Emission Spectroscopy

    Science.gov (United States)

    Schlagen, Kenneth J.

    1992-01-01

    Constituents of solutions identified in situ. Liquid-arc/spark-excitation atomic-emission spectroscopy (LAES) is experimental variant of atomic-emission spectroscopy in which electric arc or spark established in liquid and spectrum of light from arc or spark analyzed to identify chemical elements in liquid. Observations encourage development of LAES equipment for online monitoring of process streams in such industries as metal plating, electronics, and steel, and for online monitoring of streams affecting environment.

  18. Two-cascade magnetic field stabilizer of the installation for measuring neutron electric dipole moment

    International Nuclear Information System (INIS)

    Kozlov, A.N.; Nikitenko, Yu.V.; Taran, Yu.V.

    1980-01-01

    A two-cascade magnetic field stabilizer of installation for the measurement of neutron electrjcal dipole moment (EDM) using ultracold neutrons has been constructed and tested. Quantum cesium magnetometers (QCM) with optical pumping placed inside a ferromagnetic screen were used as primary convertors of the magnetic field. A stabilization coefficient of 4x10 5 in a bandwidth of 10 -3 -3x10 -3 Hz in the presence of magnetic noise of an amplitude up to 50 nT was obtained using QCM with Ssub(Z)-signal in the inner and outer cascades having transfer ratios of 300 and 600, respectively. Mean square amplitude of magnetic field fluctuations was below 0.O5 pT. Stabilization in a wider frequency band was performed using QCM with Ssub(Z)-signal in the inner cascade and QCM with Ssub(X)-signal in the outer cascade. In particular, the mean square amplitude of magnetic field fluctuations within a bandwidth of 0.1-1 Hz and 1-10 Hz was below 1 nT and 15 nT respectively

  19. Thermal efficiency on welding of AA6061-T6 alloy by modified indirect electric arc and current signals digitalisation; Eficiencia termica en soldadura de la aleacion AA6061-T6 por arco electrico indirecto modificado y digitalizacion de senales de intensidad de corriente

    Energy Technology Data Exchange (ETDEWEB)

    Ambriz, R. R.; Barrera, G.; Garcia, R.; Lopez, V. H.

    2009-07-01

    The results of the thermal efficiency on welding by modified indirect electric arc technique (MIEA) [1] of the 6061- T6 aluminum alloy are presented. These values are in a range of 90 to 94 %, which depend of the preheating employed. Thermal efficiency was obtained by means of a balance energy which considers the heat input, the amount of melted mass of the welding profiles, and welding parameters during the joining, especially of the arc current data acquisition. Also, some dimensionless parameters were employed in order to determine the approximation grade of the melted pool, the heat affected zone (HAZ), and their corresponding values with the experimental results. (Author) 13 refs.

  20. Proposition of a modification to the VAR process and its application in the consolidation of pressed zircaloy chips and the evaluation of the dynamical system of the electric arc; Proposicao de um processo alternativo a fusao via forno VAR para a consolidacao de cavacos prensados de zircaloy e estudo do sistema dinamico do arco eletrico

    Energy Technology Data Exchange (ETDEWEB)

    Mucsi, Cristiano Stefano

    2005-07-01

    The objective of this work is the investigation of a new process as an alternative to the Vacuum Arc Remelting technology in the consolidation of Zircaloy chips. A procedure is proposed for the recycling of primary Zircaloy scraps by means of a modified VAR furnace. The performed studies were made in order to optimise the low cost new devices added to existing VAR furnace prototype, find ideal operational conditions, evaluate data acquisition system and the electric arc dynamical system in order to made viable the automated control of the modified VAR prototype. A funnel-crucible special device was developed and installed in a VAR prototype furnace allowing ingots to be obtained from pressed chips. This indicated the viability of creation of a new process for the consolidation of Zircaloy chips. The voltage of the electric arc during the melting runs was digitally recorded allowing the evaluation of the electric arc dynamics by using the topological invariant of the system: correlation dimension and the higher Liapunov exponent. (author)

  1. Investigation of the structural, surface, optical and electrical properties of the Indium doped CuxO thin films deposited by a thermionic vacuum arc

    Science.gov (United States)

    Musaoğlu, Caner; Pat, Suat; Özen, Soner; Korkmaz, Şadan; Mohammadigharehbagh, Reza

    2018-03-01

    In this study, investigation of some physical properties of In-doped CuxO thin films onto amorphous glass substrates were done. The thin films were depsoied by thermionic vacuum arc technique (TVA). TVA technique gives a thin film with lower precursor impurity according to the other chemical and physical depsoition methods. The microstructural properties of the produced thin films was determined by x-ray diffraction device (XRD). The thickness values were measured as to be 30 nm and 60 nm, respectively. The miller indices of the thin films’ crystalline planes were determined as to be Cu (111), CuO (\\bar{1} 12), CuInO2 (107) and Cu2O (200), Cu (111), CuO (\\bar{1} 12), CuO (\\bar{2} 02), CuInO2 (015) for sample C1 and C2, respectively. The produced In-doped CuO thin films are in polycrystalline structure. The surface properties of produced In doped CuO thin films were determined by using an atomic force microscope (AFM) and field emission scanning electron microscope (FESEM) tools. The optical properties of the In doped CuO thin films were determined by UV–vis spectrophotometer, interferometer, and photoluminescence devices. p-type semiconductor thin film was obtained by TVA depsoition.

  2. 'LTE-diffusion approximation' for arc calculations

    International Nuclear Information System (INIS)

    Lowke, J J; Tanaka, M

    2006-01-01

    This paper proposes the use of the 'LTE-diffusion approximation' for predicting the properties of electric arcs. Under this approximation, local thermodynamic equilibrium (LTE) is assumed, with a particular mesh size near the electrodes chosen to be equal to the 'diffusion length', based on D e /W, where D e is the electron diffusion coefficient and W is the electron drift velocity. This approximation overcomes the problem that the equilibrium electrical conductivity in the arc near the electrodes is almost zero, which makes accurate calculations using LTE impossible in the limit of small mesh size, as then voltages would tend towards infinity. Use of the LTE-diffusion approximation for a 200 A arc with a thermionic cathode gives predictions of total arc voltage, electrode temperatures, arc temperatures and radial profiles of heat flux density and current density at the anode that are in approximate agreement with more accurate calculations which include an account of the diffusion of electric charges to the electrodes, and also with experimental results. Calculations, which include diffusion of charges, agree with experimental results of current and heat flux density as a function of radius if the Milne boundary condition is used at the anode surface rather than imposing zero charge density at the anode

  3. Transient Dynamics of Electric Power Systems: Direct Stability Assessment and Chaotic Motions

    Science.gov (United States)

    Chu, Chia-Chi

    A power system is continuously experiencing disturbances. Analyzing, predicting, and controlling transient dynamics, which describe transient behaviors of the power system following disturbances, is a major concern in the planning and operation of a power utility. Important conclusions and decisions are made based on the result of system transient behaviors. As today's power network becomes highly interconnected and much more complex, it has become essential to enhance the fundamental understanding of transient dynamics, and to develop fast and reliable computational algorithms. In this thesis, we emphasize mathematical rigor rather than physical insight. Nonlinear dynamical system theory is applied to study two fundamental topics: direct stability assessment and chaotic motions. Conventionally, power system stability is determined by calculating the time-domain transient behaviors for a given disturbance. In contrast, direct methods identify whether or not the system will remain stable once the disturbance is removed by comparing the corresponding energy value of the post-fault system to a calculated threshold value. Direct methods not only avoid the time-consuming numerical integration of the time domain approach, but also provide a quantitative measure of the degree of system stability. We present a general framework for the theoretical foundations of direct methods. Canonical representations of network-reduction models as well as network-preserving models are proposed to facilitate the analysis and the construction of energy functions of various power system models. An advanced and practical method, called the boundary of stability region based controlling unstable equilibrium point method (BCU method), of computing the controlling unstable equilibrium point is proposed along with its theoretical foundation. Numerical solution algorithms capable of supporting on-line applications of direct methods are provided. Further possible improvements and enhancements are

  4. Innovative electrical technique for in-place stabilization of contaminated soils

    International Nuclear Information System (INIS)

    Buelt, J.L.; FitzPatrick, V.F.; Timmerman, C.L.

    1984-05-01

    This paper discusses an emerging thermoelectric process known as in situ vitrification as a potential method for stabilizing buried waste inplace. The paper describes the Scott-Tee power system for the large-scale testing unit and how its design was developed. A brief synopsis of the performance assessments that have been conducted with regard to waste form quality, effect of soil conditions on processing, physical constraints of the process, and vitrification of soils containing organic and hazardous components is presented. A summary of an economic analysis is also provided

  5. Electricity

    Indian Academy of Sciences (India)

    which removes the heat produced In the core and the colis. I represents an Isolator which is a kind of. 'switch' used to isolate the station from the grid. Note the huge Insulators (marked I) that are used. The steel structures marked S support the conductors through insulators (courtesy: Kirloskar Electric Company, Bangalore).

  6. Electrical conductivities and chemical stabilities of mixed conducting pyrochlores for SOFC applications

    DEFF Research Database (Denmark)

    Holtappels, P.; Poulsen, F.W.; Mogensen, Mogens Bjerg

    2000-01-01

    Pyrochlores with praseodymium as the A-site cation and zirconium, tin, cerium and manganese cations on the B-site were prepared in air and their electrical conductivities were investigated as a function of oxygen partial pressure and temperature. Pure Pr2Zr2O7+/-delta as well as samples modified...... on the B-site with 5% Mn or 20% Ce show conductivities, which are lower than 2 x 10(-3) S/cm at 1000 degreesC in H-2/H2O atmospheres. Electronic p-type conductivity was indicated for these materials in oxygen/nitrogen mixtures. The electrically conducting pyrochlore solid solutions Gd2TiMoO7+/-delta and Gd......2Ti0.6Mo1.4O7+/-delta were synthesised and investigated in 1% H-2/3% H2O/96% N-2. No formation of a new phase by reaction with YSZ was indicated after exposure to this atmosphere at 1000 degreesC for 1000 h. Pr2Sn2O7+/-delta modified with 5% indium on the B-site exhibited a conductivity in air of 6...

  7. arcControlTower: the System for Atlas Production and Analysis on ARC

    Science.gov (United States)

    Filipčič, Andrej; ATLAS Collaboration

    2011-12-01

    PanDA, the Atlas management and distribution system for production and analysis jobs on EGEE and OSG clusters, is based on pilot jobs to increase the throughput and stability of the job execution on grid. The ARC middleware uses a specific approach which tightly connects the job requirements with cluster capabilities like resource usage, software availability and caching of input files. The pilot concept renders the ARC features useless. The arcControlTower is the job submission system which merges the pilot benefits and ARC advantages. It takes the pilot payload from the panda server and submits the jobs to the Nordugrid ARC clusters as regular jobs, with all the job resources known in advance. All the pilot communication with the PanDA server is done by the arcControlTower, so it plays the role of a pilot factory and the pilot itself. There are several advantages to this approach: no grid middleware is needed on the worker nodes, the fair-share between the production and user jobs is tuned with the arcControlTower load parameters, the jobs can be controlled by ARC client tools. The system could be extended to other submission systems using central distribution.

  8. arcControlTower: the System for Atlas Production and Analysis on ARC

    International Nuclear Information System (INIS)

    Filipcic, Andrej

    2011-01-01

    PanDA, the Atlas management and distribution system for production and analysis jobs on EGEE and OSG clusters, is based on pilot jobs to increase the throughput and stability of the job execution on grid. The ARC middleware uses a specific approach which tightly connects the job requirements with cluster capabilities like resource usage, software availability and caching of input files. The pilot concept renders the ARC features useless. The arcControlTower is the job submission system which merges the pilot benefits and ARC advantages. It takes the pilot payload from the panda server and submits the jobs to the Nordugrid ARC clusters as regular jobs, with all the job resources known in advance. All the pilot communication with the PanDA server is done by the arcControlTower, so it plays the role of a pilot factory and the pilot itself. There are several advantages to this approach: no grid middleware is needed on the worker nodes, the fair-share between the production and user jobs is tuned with the arcControlTower load parameters, the jobs can be controlled by ARC client tools. The system could be extended to other submission systems using central distribution.

  9. Adaptive system for automatic stabilization of the power factor for electric drives of separation device by means of serially connected capacitors bank

    Science.gov (United States)

    Borisevich, V. D.; Juromskiy, V. M.

    2016-09-01

    A method for designing adaptive systems for automatic extremum search to stabilize the power factor of local electric power system of electric is considered. It consists in application of the serially connected capacitors compensating the reactive component of the total electric power of in parallel connected centrifugal machines usually called as an aggregate. Operation of the system just demands measuring voltage at the output of the static frequency converter for electric drives. The proposed control system is designed to stabilize the power factor close to unity in a case of alteration of parameters of a separation cascade or a single separation device in an aggregate. Such system can be operated continuously or connected occasionally depending on a technological situation. In addition, it totally excludes the phenomenon of overcompensation.

  10. Monitoring ARC services with GangliARC

    International Nuclear Information System (INIS)

    Cameron, D; Karpenko, D

    2012-01-01

    Monitoring of Grid services is essential to provide a smooth experience for users and provide fast and easy to understand diagnostics for administrators running the services. GangliARC makes use of the widely-used Ganglia monitoring tool to present web-based graphical metrics of the ARC computing element. These include statistics of running and finished jobs, data transfer metrics, as well as showing the availability of the computing element and hardware information such as free disk space left in the ARC cache. Ganglia presents metrics as graphs of the value of the metric over time and shows an easily-digestable summary of how the system is performing, and enables quick and easy diagnosis of common problems. This paper describes how GangliARC works and shows numerous examples of how the generated data can quickly be used by an administrator to investigate problems. It also presents possibilities of combining GangliARC with other commonly-used monitoring tools such as Nagios to easily integrate ARC monitoring into the regular monitoring infrastructure of any site or computing centre.

  11. Electric field-driven, magnetically-stabilized ferro-emulsion phase contactor

    Science.gov (United States)

    Scott, Timothy C.

    1990-01-01

    Methods and systems for interfacial surface area contact between a dispersed phase liquid and a continuous phase liquid in counter-current flow for purposes such as solvent extraction. Initial droplets of a dispersed phase liquid material containing ferromagnetic particles functioning as a "packing" are introduced to a counter-current flow of the continuous phase. A high intensity pulsed electric field is applied so as to shatter the initial droplets into a ferromagnetic emulsion comprising many smaller daughter droplets having a greater combined total surface area than that of the initial droplets in contact with the continuous phase material. A magnetic field is applied to control the position of the ferromagnetic emulsion for enhanced coalescence of the daughter droplets into larger reformed droplets.

  12. Voltage Stability Control of Electrical Network Using Intelligent Load Shedding Strategy Based on Fuzzy Logic

    Directory of Open Access Journals (Sweden)

    Houda Jouini

    2010-01-01

    Full Text Available As a perspective to ensure the power system stability and to avoid the vulnerability leading to the blackouts, several preventive and curative means are adopted. In order to avoid the voltage collapse, load shedding schemes represent a suitable action to maintain the power system service quality and to control its vulnerability. In this paper, we try to propose an intelligent load shedding strategy as a new approach based on fuzzy controllers. This strategy was founded on the calculation of generated power sensitivity degree related to those injected at different network buses. During the fault phase, fuzzy controller algorithms generate monitor vectors ensuring a precalculated load shedding ratio in the purpose to reestablish the power balance and conduct the network to a new steady state.

  13. A Robust Control Method for Lateral Stability Control of In-Wheel Motored Electric Vehicle Based on Sideslip Angle Observer

    Directory of Open Access Journals (Sweden)

    Yaxiong Wang

    2018-01-01

    Full Text Available In-wheel motored powertrain on electric vehicles has more potential in maneuverability and active safety control. This paper investigates the longitudinal and lateral integrated control through the active front steering and yaw moment control systems considering the saturation characteristics of tire forces. To obtain the vehicle sideslip angle of mass center, the virtual lateral tire force sensors are designed based on the unscented Kalman filtering (UKF. And the sideslip angle is estimated by using the dynamics-based approaches. Moreover, based on the estimated vehicle state information, an upper level control system by using robust control theory is proposed to specify a desired yaw moment and correction front steering angle to work on the electric vehicles. The robustness of proposed algorithm is also analyzed. The wheel torques are distributed optimally by the wheel torque distribution control algorithm. Numerical simulation is carried out in Matlab/Simulink-Carsim cosimulation environment to demonstrate the effectiveness of the designed robust control algorithm for lateral stability control of in-wheel motored vehicle.

  14. Model predictive controller-based multi-model control system for longitudinal stability of distributed drive electric vehicle.

    Science.gov (United States)

    Shi, Ke; Yuan, Xiaofang; Liu, Liang

    2018-01-01

    Distributed drive electric vehicle(DDEV) has been widely researched recently, its longitudinal stability is a very important research topic. Conventional wheel slip ratio control strategies are usually designed for one special operating mode and the optimal performance cannot be obtained as DDEV works under various operating modes. In this paper, a novel model predictive controller-based multi-model control system (MPC-MMCS) is proposed to solve the longitudinal stability problem of DDEV. Firstly, the operation state of DDEV is summarized as three kinds of typical operating modes. A submodel set is established to accurately represent the state value of the corresponding operating mode. Secondly, the matching degree between the state of actual DDEV and each submodel is analyzed. The matching degree is expressed as the weight coefficient and calculated by a modified recursive Bayes theorem. Thirdly, a nonlinear MPC is designed to achieve the optimal wheel slip ratio for each submodel. The optimal design of MPC is realized by parallel chaos optimization algorithm(PCOA)with computational accuracy and efficiency. Finally, the control output of MPC-MMCS is computed by the weighted output of each MPC to achieve smooth switching between operating modes. The proposed MPC-MMCS is evaluated on eight degrees of freedom(8DOF)DDEV model simulation platform and simulation results of different condition show the benefits of the proposed control system. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  15. Fluorinated polymer-grafted organic dielectrics for organic field-effect transistors with low-voltage and electrical stability.

    Science.gov (United States)

    Kim, Kyunghun; Kim, Haekyoung; Kim, Se Hyun; Park, Chan Eon

    2015-07-14

    The electrical stabilities of low-voltage organic field-effect transistors (OFETs) were improved by applying graftable fluorinated polymer (gPFS) layers onto poly(4-vinyl phenol)-based cross-linked dielectrics (cPVP). As a result, a smooth and hydrophobic surface was formed, and the dielectric film displayed a low-leakage current density. The chemisorbed gPFS groups enabled the solution processing of an overlying 5,11-bis(triethylsilylethynyl)anthradithiophene semiconductor, which formed favorable terrace-like crystalline structures after solvent annealing. The top-contact OFETs showed superior operational stability compared to cPVP-based OFETs. Hysteresis was negligible, and the off-current of the transfer curve was one order of magnitude lower than that obtained from cPVP-based OFETs. The threshold voltage shift measured after a sustained gate bias stress for 1 h decreased significantly after introduction of the hydrophobic gPFS treatment; the energetic barrier to creating charge trapping sites increased, and the trap distribution narrowed, as supported by the stretched exponential function model.

  16. Anatomy of terminal moraine segments and implied lake stability on Ngozumpa Glacier, Nepal, from electrical resistivity tomography (ERT)

    Science.gov (United States)

    Thompson, Sarah S.; Kulessa, Bernd; Benn, Douglas I.; Mertes, Jordan R.

    2017-04-01

    Moraine-dammed lakes at debris-covered glaciers are becoming increasingly common and pose significant outburst flood hazards if the dam is breached. While moraine subsurface structure and internal processes are likely to influence dam stability, only few sites have so far been investigated. We conducted electrical resistivity tomography (ERT) surveys at two sites on the terminal moraine complex of the Ngozumpa Glacier, Nepal, to aid assessment of future terminus stability. The resistivity signature of glacier ice at the site (100-15 kΩ m) is more consistent with values measured from cold glacier ice and while this may be feasible, uncertainties in the data inversion introduce ambiguity to this thermal interpretation. However, the ERT data does provide a significant improvement to our knowledge of the subsurface characteristics at these sites, clearly showing the presence (or absence) of glacier ice. Our interpretation is that of a highly complex latero-terminal moraine, resulting from interaction between previous glacier advance, recession and outburst flooding. If the base-level Spillway Lake continues to expand to a fully formed moraine-dammed glacial lake, the degradation of the ice core could have implications for glacial lake outburst risk.

  17. Quasi-equilibrium channel model of an constant current arc

    Directory of Open Access Journals (Sweden)

    Gerasimov Alexander V.

    2003-01-01

    Full Text Available The rather simple method of calculation of electronic and gas temperature in the channel of arc of plasma generator is offered. This method is based on self-consistent two-temperature channel model of an electric arc. The method proposed enables to obtain radial allocation of gas and electronic temperatures in a non-conducting zone of an constant current arc, for prescribed parameters of discharge (current intensity and power of the discharge, with enough good precision. The results obtained can be used in model and engineering calculations to estimate gas and electronic temperatures in the channel of an arc plasma generator.

  18. Analisis dan Reduksi Bahaya ARC Flash pada Sistem Kelistrikan

    Directory of Open Access Journals (Sweden)

    Firman Aji Prasongko

    2012-09-01

    Full Text Available Upaya terakhir untuk menghitung bahaya yang berhubungan dengan potensi bahaya arc flash bergantung pada proteksi arus lebih untuk menghilangkan kondisi saat diberi gangguan. Efektivitas berbagai perangkat ditentukan oleh clearing time terkait dengan gangguan arus maksimum yang ada untuk setiap lokasi sistem. Industri komersial mulai melakukan prosedur pelabelan arc flash dan mulai mengenali pencegahan arc flash sebagai bagian dari program safety, perhitungan current method memungkinkan untuk menghitung incident energy (cal/cm² terkait dengan gangguan maksimum tiga phasa. Kesalahan terbanyak adalah besaran arus kurang dari besaran arus tiga phasa maksimum. Dalam Tugas Akhir ini akan dibahas perhitungan energy dan durasi lama terjadinya arc flash pada system kelistrikan pada electrical room.

  19. Aplicabilidad del monitoreo de emisiones del arco eléctrico para el control de calidad en el proceso MAG-S Applicability of monitoring of electric arc emissions for quality control in MAG-S process

    Directory of Open Access Journals (Sweden)

    Eber Huanca Cayo

    2011-12-01

    TIG welding processes. During welding, the arc produces acoustic and electromagnetic emissions that occur as sound and light. The aim of this paper is to show that the emissions of the welding arc can be used to monitoring the quality of welding in MAG-S process. Multiple welding experiments were performed in flat position; in each experiment were induced perturbations by grease on plate and shielding gas absence. Current and voltage signals and arc emission signals were acquired simultaneously. The short circuit frequency was measured from acoustic and electromagnetic emission in the ultraviolet band. The welding stability was measured from infrared emission. The results show that the emissions of welding arc can be used for monitoring and detecting of disturbances in welding and with the understanding of the variations of each disturbance could be possible to identify certain types of disturbances.

  20. Analysis and control of excitation, field weakening and stability in direct torque controlled electrically excited synchronous motor drives

    Energy Technology Data Exchange (ETDEWEB)

    Pyrhoenen, O.

    1998-12-31

    Direct torque control (DTC) is a new control method for rotating field electrical machines. DTC controls directly the motor stator flux linkage with the stator voltage, and no stator current controllers are used. With the DTC method very good torque dynamics can be achieved. Until now, DTC has been applied to asynchronous motor drives. The purpose of this work is to analyse the applicability of DTC to electrically excited synchronous motor drives. Compared with asynchronous motor drives, electrically excited synchronous motor drives require an additional control for the rotor field current. The field current control is called excitation control in this study. The dependence of the static and dynamic performance of DTC synchronous motor drives on the excitation control has been analysed and a straightforward excitation control method has been developed and tested. In the field weakening range the stator flux linkage modulus must be reduced in order to keep the electro motive force of the synchronous motor smaller than the stator voltage and in order to maintain a sufficient voltage reserve. The dynamic performance of the DTC synchronous motor drive depends on the stator flux linkage modulus. Another important factor for the dynamic performance in the field weakening range is the excitation control. The field weakening analysis considers both dependencies. A modified excitation control method, which maximises the dynamic performance in the field weakening range, has been developed. In synchronous motor drives the load angle must be kept in a stabile working area in order to avoid loss of synchronism. The traditional vector control methods allow to adjust the load angle of the synchronous motor directly by the stator current control. In the DTC synchronous motor drive the load angle is not a directly controllable variable, but it is formed freely according to the motor`s electromagnetic state and load. The load angle can be limited indirectly by limiting the torque

  1. Hypergravity effects on glide arc plasma

    NARCIS (Netherlands)

    Šperka, J.; Souček, P.; van Loon, J.J.W.A.; Dowson, A.; Schwarz, C.; Krause, J.; Kroesen, G.; Kudrle, V.

    2013-01-01

    The behaviour of a special type of electric discharge - the gliding arc plasma - has been investigated in hypergravity (1g-18g) using the Large Diameter Centrifuge (LDC) at ESA/ESTEC. The discharge voltage and current together with the videosignal from a fast camera have been recorded during the

  2. The effect of adsorbates on the electrical stability of graphene studied by transient photocurrent spectroscopy

    Science.gov (United States)

    Kalkan, S. B.; Aydın, H.; Özkendir, D.; ćelebi, C.

    2018-01-01

    Adsorbate induced variations in the electrical conductivity of graphene layers with two different types of charge carriers are investigated by using the Transient Photocurrent Spectroscopy (TPS) measurement technique. In-vacuum TPS measurements taken for a duration of 5 ks revealed that the adsorption/desorption of atmospheric adsorbates leads to more than a 110% increment and a 45% decrement in the conductivity of epitaxial graphene (n-type) and chemical vapor deposition graphene (p-type) layers on semi-insulating silicon carbide (SiC) substrates, respectively. The graphene layers on SiC are encapsulated and passivated with a thin SiO2 film grown by the Pulsed Electron Deposition method. The measurements conducted for short periods and a few cycles showed that the encapsulation process completely suppresses the time dependent conductivity instability of graphene independent of its charge carrier type. The obtained results are used to construct an experimental model for identifying adsorbate related conductivity variations in graphene and also in other 2D materials with an inherently high surface-to-volume ratio.

  3. Roadmap for the ARC Grid Middleware

    DEFF Research Database (Denmark)

    Kleist, Josva; Eerola, Paula; Ekelöf, Tord

    2006-01-01

    The Advanced Resource Connector (ARC) or the NorduGrid middleware is an open source software solution enabling production quality computational and data Grids, with special emphasis on scalability, stability, reliability and performance. Since its first release in May 2002, the middleware is depl...

  4. ON ALGORITHMS CREATION FOR STRAPDOWN STABILIZED GYROCOMPASS OPERATION BASED ON ELECTRICALLY SUSPENDED GYROSCOPE

    Directory of Open Access Journals (Sweden)

    Gennady I. Emelyantsev

    2014-09-01

    Full Text Available The paper presents operation algorithms of ESG-based strapdown stabilized gyrocompass (SSGC located onboard a mobile vehicle. Initial alignment mode and calibration of drift model coefficients onboard a vehicle is aided by reference attitude (heading, pitch and roll angles and position data. The required reference attitude parameters can be generated by joint processing of data from MEMS IMU with gyros and accelerometers and GPS compass. Depending on the vehicle dynamics and required accuracy of generated heading, the system may use IMU based on the fiber-optic gyros and accelerometers instead of MEMS to construct the place vertical. Specific features of SSGC algorithms in heading generation are considered. Calibration and corrected operation modes of the system are described. The SSGC uses two ESGs with orthogonal angular momentum vectors, where one gyro is the reference (unit vector of its angular momentum is aligned with the celestial axis and the other one is virtual (with zero misalignments with respect to the inertial frame, and zero drift model coefficients. Joint processing of SSGC data and external position aiding is realized by extended Kalman filter with full-state feedback control. Simulation modeling results of the system operation algorithms are presented. Simulation modeling has confirmed the system compass effect and determined the time required for calibration of ESG with solid-rotor. The results have been applied at «Concern CSRI “Elektropribor”», JSC

  5. Utilización del polvo de acería de horno de arco eléctrico. // Use of powder produced by electric arc furnaces at steel plants.

    Directory of Open Access Journals (Sweden)

    D. Tápanes Robau

    2001-01-01

    Full Text Available El polvo de las Acerías de Horno de Arco Eléctrico se produce como consecuencia de la producción de Acero, durante ladepuración de los gases, y, en menor medida, en sus equipos de captación de aire. Estos polvos deben ser captados por lossistemas de depuración del taller. Con el presente trabajo pretendemos darle utilidad a un producto de desecho como es elpolvo, mejorar las condiciones ambientales en el taller, elevar la calidad del pavimento u hormigón asfáltico mediante lavariación de sus propiedades y disminuir el costo de la tonelada de acero mediante la comercialización de estos productosde desecho.Palabras claves: Polvos, aglutinantes, composición química, pruebas realizadas._______________________________________________________________________________SummaryThe powder generated by electric arc furnaces at steel plants is the result of processes such as the production of steel, thepurification of gases and, capturing air equipment .This article shows a method for recycling waste material – powder in this case- which also contributes to improve the steelplant environment, provides the possibility of improving asphalt paving and makes the production of steel cheaper throughthe commercialization of waste materials.Key words: Powder, binder, tests, chemical composition.

  6. Effects of electric field and Coriolis force on electrohydrodynamic stability of poorly conducting couple stress parallel fluid flow in a channel

    International Nuclear Information System (INIS)

    Shankar, B.M.; Rudraiah, N.

    2013-01-01

    The effective functioning of microfluidic devices in chemical, electrical and mechanical engineering involving fluidics particularly those having vibrations and petroleum products containing organic, inorganic and other microfluidics require understanding and control of stability of poorly conducting parallel fluid flows. The electrical conductivity, σ, of a poorly conducting fluidics, increases with the temperature and the concentration of freely suspended particles like RBC, WBC and so on in the blood, the hylauronic acid (HA) and nutrients of synovial fluid in synovial joints will spin producing microrotation, forming micropolar fluid of Eringen. The presence of Deuterium - Tritium (DT) in inertial fusion target (IFT) may also be modeled using micropolar fluid theory of Eringen. A particular case of micropolar fluid theory when microrotation balances with the natural vorticity of a poorly conducting fluidics in the presence of an electric field is called ‘electrohydrodynamic couple stress fluid’ (EHDCF). These EHDCFs exhibit a variation of electrical conductivity, ∇ σ, increasing with temperature and concentration of freely suspended particles, releases the charges from the nuclei forming distribution of charge density, ρ e . These charges induce an electric field, 1 E i . If need be, we can apply an electric field, 1 E a , by embedding electrodes of different potentials at the boundaries. The total electric field, 1 E = 1 E i + 1 E a , produces a current density, 1 J = ρ σ 1 E, according to Ohm’s law and also produces an electric force, 1 F σ = σ 1 E. This current 1 J acts as sensing and the force, 1 F σ acts as actuation. These two properties make the poorly conducting couple stress fluid to act as a smart material. The objective of this paper is to show that EHDCV in presence of coriolis force plays a significant role in controlling the stability of parallel flows which is essential for an effective functioning of machineries that occur in

  7. Structures, phase stabilities, and electrical potentials of Li-Si battery anode materials

    KAUST Repository

    Tipton, William W.

    2013-05-28

    The Li-Si materials system holds promise for use as an anode in Li-ion battery applications. For this system, we determine the charge capacity, voltage profiles, and energy storage density solely by ab initio methods without any experimental input. We determine the energetics of the stable and metastable Li-Si phases likely to form during the charging and discharging of a battery. Ab initio molecular dynamics simulations are used to model the structure of amorphous Li-Si as a function of composition, and a genetic algorithm coupled to density-functional theory searches the Li-Si binary phase diagram for small-cell, metastable crystal structures. Calculations of the phonon densities of states using density-functional perturbation theory for selected structures determine the importance of vibrational, including zero-point, contributions to the free energies. The energetics and local structural motifs of these metastable Li-Si phases closely resemble those of the amorphous phases, making these small unit cell crystal phases good approximants of the amorphous phase for use in further studies. The charge capacity is estimated, and the electrical potential profiles and the energy density of Li-Si anodes are predicted. We find, in good agreement with experimental measurements, that the formation of amorphous Li-Si only slightly increases the anode potential. Additionally, the genetic algorithm identifies a previously unreported member of the Li-Si binary phase diagram with composition Li5Si2 which is stable at 0 K with respect to previously known phases. We discuss its relationship to the partially occupied Li7Si3 phase. © 2013 American Physical Society.

  8. Optical arc sensor using energy harvesting power source

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyoo Nam, E-mail: knchoi@inu.ac.kr; Rho, Hee Hyuk, E-mail: rdoubleh0902@inu.ac.kr [Dept. of Information and Telecommunication Engineering Incheon National University Incheon 22012 (Korea, Republic of)

    2016-06-03

    Wireless sensors without external power supply gained considerable attention due to convenience both in installation and operation. Optical arc detecting sensor equipping with self sustaining power supply using energy harvesting method was investigated. Continuous energy harvesting method was attempted using thermoelectric generator to supply standby power in micro ampere scale and operating power in mA scale. Peltier module with heat-sink was used for high efficiency electricity generator. Optical arc detecting sensor with hybrid filter showed insensitivity to fluorescent and incandescent lamps under simulated distribution panel condition. Signal processing using integrating function showed selective arc discharge detection capability to different arc energy levels, with a resolution below 17 J energy difference, unaffected by bursting arc waveform. The sensor showed possibility for application to arc discharge detecting sensor in power distribution panel. Also experiment with proposed continuous energy harvesting method using thermoelectric power showed possibility as a self sustainable power source of remote sensor.

  9. Optical arc sensor using energy harvesting power source

    Science.gov (United States)

    Choi, Kyoo Nam; Rho, Hee Hyuk

    2016-06-01

    Wireless sensors without external power supply gained considerable attention due to convenience both in installation and operation. Optical arc detecting sensor equipping with self sustaining power supply using energy harvesting method was investigated. Continuous energy harvesting method was attempted using thermoelectric generator to supply standby power in micro ampere scale and operating power in mA scale. Peltier module with heat-sink was used for high efficiency electricity generator. Optical arc detecting sensor with hybrid filter showed insensitivity to fluorescent and incandescent lamps under simulated distribution panel condition. Signal processing using integrating function showed selective arc discharge detection capability to different arc energy levels, with a resolution below 17J energy difference, unaffected by bursting arc waveform. The sensor showed possibility for application to arc discharge detecting sensor in power distribution panel. Also experiment with proposed continuous energy harvesting method using thermoelectric power showed possibility as a self sustainable power source of remote sensor.

  10. Sheath and arc-column voltages in high-pressure arc discharges

    International Nuclear Information System (INIS)

    Benilov, M S; Benilova, L G; Li Heping; Wu Guiqing

    2012-01-01

    Electrical characteristics of a 1 cm-long free-burning atmospheric-pressure argon arc are calculated by means of a model taking into account the existence of a near-cathode space-charge sheath and the discrepancy between the electron and heavy-particle temperatures in the arc column. The computed arc voltage exhibits a variation with the arc current I similar to the one revealed by the experiment and exceeds experimental values by no more than approximately 2 V in the current range 20-175 A. The sheath contributes about two-thirds or more of the arc voltage. The LTE model predicts a different variation of the arc voltage with I and underestimates the experimental values appreciably for low currents but by no more than approximately 2 V for I ≳ 120 A. However, the latter can hardly be considered as a proof of unimportance of the space-charge sheath at high currents: the LTE model overestimates both the resistance of the bulk of the arc column and the resistance of the part of the column that is adjacent to the cathode, and this overestimation to a certain extent compensates for the neglect of the voltage drop in the sheath. Furthermore, if the latter resistance were evaluated in the framework of the LTE model in an accurate way, then the overestimation would be still much stronger and the obtained voltage would significantly exceed those observed in the experiment.

  11. Plant uptake and geochemical phase distribution of Cd, Pb and Zn from soils after application of baghouse dust from the electric arc furnace production of steel

    Energy Technology Data Exchange (ETDEWEB)

    Rule, J.H. [Old Dominion Univ., Norfolk, VA (United States). Dept. of Chemistry and Biochemistry; Adriano, D.C. [Georgia Univ., Savannah River Ecology Laboratory, Aiken (United States)

    1997-12-31

    The objectives of this study are to determine the uptake of Cd, Pb and Zn from two soils (silt loam and sandy loam) by the common dandelion, Taraxacum officinale Weber, and ragweed, Ambrosia artemisiifolia L., after application of varying rates of flue dust, to determine the geochemical phase distribution of Cd, Pb and Zn of treated soils, to examine the effect of pH on the phase distribution and plant uptake and to measure the correlation between plant uptake and metals in the geochemical phases. Carbonate, including metal hydroxides, was the major geochemical phase for the metals in the flue dust and treated soils. Especially for the plants grown on the silt loam, yield decreased dramatically as flue dust treatment rate increased and a significant pH effect was observed. Plant uptake of the metals increased with increasing treatment level but the pattern of uptake varied with the element and plant species. Concentrations of the metals were generally greater in plant roots than leaves or stems. Due to very low biomass at high treatment levels, neither species seems to have potential for stabilization of highly contaminated soils but further studies are warranted on the use of the dandelion as a phyto-monitor. Typically, there was a significant correlation between plant concentrations and levels in all soil geochemical phases for all metals. The results of this study confirm the utility of selective sequential chemical extractants in predicting plant uptake of trace metals from contaminated soils

  12. Arc generation from sputtering plasma-dielectric inclusion interactions

    International Nuclear Information System (INIS)

    Wickersham, C.E. Jr.; Poole, J.E.; Fan, J.S.

    2002-01-01

    Arcing during sputter deposition and etching is a significant cause of particle defect generation during device fabrication. In this article we report on the effect of aluminum oxide inclusion size, shape, and orientation on the propensity for arcing during sputtering of aluminum targets. The size, shape, and orientation of a dielectric inclusion plays a major role in determining the propensity for arcing and macroparticle emission. In previous studies we found that there is a critical inclusion size required for arcing to occur. In this article we used high-speed videos, electric arc detection, and measurements of particle defect density on wafers to study the effect of Al 2 O 3 inclusion size, shape, and orientation on arc rate, intensity, and silicon wafer particle defect density. We found that the cross-sectional area of the inclusion exposed to the sputtering plasma is the critical parameter that determines the arc rate and rate of macroparticle emission. Analysis of the arc rate, particle defect density, and the intensity of the optical emission from the arcing plasma indicates that the critical aluminum oxide inclusion area for arcing is 0.22±0.1 mm2 when the sputtering plasma sheath dark-space λ d , is 0.51 mm. Inclusions with areas greater than this critical value readily induce arcing and macroparticle ejection during sputtering. Inclusions below this critical size do not cause arcing or macroparticle ejection. When the inclusion major axis is longer than 2λ d and lies perpendicular to the sputter erosion track tangent, the arcing activity increases significantly over the case where the inclusion major axis lies parallel to the erosion track tangent

  13. Surface profile gradient in amorphous Ta{sub 2}O{sub 5} semi conductive layers regulates nanoscale electric current stability

    Energy Technology Data Exchange (ETDEWEB)

    Cefalas, A.C., E-mail: ccefalas@eie.gr [National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, Athens 11635 (Greece); Kollia, Z.; Spyropoulos-Antonakakis, N.; Gavriil, V. [National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, Athens 11635 (Greece); Christofilos, D.; Kourouklis, G. [Physics Division, School of Technology, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece); Semashko, V.V.; Pavlov, V. [Kazan Federal University, Institute of Physics, 18 Kremljovskaja str., Kazan 420008 (Russian Federation); Sarantopoulou, E. [National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, Athens 11635 (Greece); Kazan Federal University, Institute of Physics, 18 Kremljovskaja str., Kazan 420008 (Russian Federation)

    2017-02-28

    Highlights: • The work links the surface morphology of amorphous semiconductors with both their electric-thermal properties and current stability at the nanoscale (<1 μm). • Measured high correlation value between surface morphological spatial gradient and conductive electron energy spatial gradient or thermal gradient. • Unidirectional current stability is associated with asymmetric nanodomains along nanosize conductive paths. • Bidirectional current stability is inherent with either long conductive paths or nanosize conductive paths along symmetric nanodomains. • Conclusion: Surface design improves current stability across nanoelectonic junctions. - Abstract: A link between the morphological characteristics and the electric properties of amorphous layers is established by means of atomic, conductive, electrostatic force and thermal scanning microscopy. Using amorphous Ta{sub 2}O{sub 5} (a-Ta{sub 2}O{sub 5}) semiconductive layer, it is found that surface profile gradients (morphological gradient), are highly correlated to both the electron energy gradient of trapped electrons in interactive Coulombic sites and the thermal gradient along conductive paths and thus thermal and electric properties are correlated with surface morphology at the nanoscale. Furthermore, morphological and electron energy gradients along opposite conductive paths of electrons intrinsically impose a current stability anisotropy. For either long conductive paths (L > 1 μm) or along symmetric nanodomains, current stability for both positive and negative currents i is demonstrated. On the contrary, for short conductive paths along non-symmetric nanodomains, the set of independent variables (L, i) is spanned by two current stability/intability loci. One locus specifies a stable state for negative currents, while the other locus also describes a stable state for positive currents.

  14. Using arc voltage to locate the anode attachment in plasma arc cutting

    International Nuclear Information System (INIS)

    Osterhouse, D J; Heberlein, J V R; Lindsay, J W

    2013-01-01

    Plasma arc cutting is a widely used industrial process in which an electric arc in the form of a high velocity plasma jet is used to melt and blow away metal. The arc attaches inside the resulting cut slot, or kerf, where it both provides a large heat flux and determines the flow dynamics of the plasma. Knowledge of the position of the arc attachment is essential for understanding the phenomena present at the work piece. This work presents a new method of measuring the location of the arc attachment in which the arc voltage is measured during the cutting of a range of work piece thicknesses. The attachment location is then interpreted from the voltages. To support the validity of this method, the kerf shape, dross particle size and dross adhesion to the work piece are also observed. While these do not conclusively give an attachment location, they show patterns which are consistent with the attachment location found from the voltage measurements. The method is demonstrated on the cutting of mild steel, where the arc attachment is found to be stationary in the upper portion of the cut slot and in reasonable agreement with existing published findings. For a process optimized for the cutting of 12.7 mm mild steel, the attachment is found at a depth of 1.5–3.4 mm. For a slower process optimized for the cutting of 25.4 mm mild steel, the attachment is found at a depth of 3.4–4.8 mm, which enhances heat transfer further down in the kerf, allowing cutting of the thicker work piece. The use of arc voltage to locate the position of the arc attachment is unique when compared with existing methods because it is entirely independent of the heat distribution and visualization techniques. (paper)

  15. Welding arc initiator

    Science.gov (United States)

    Correy, T.B.

    1989-05-09

    An improved inert gas shielded tungsten arc welder is disclosed of the type wherein a tungsten electrode is shielded within a flowing inert gas, and, an arc, following ignition, burns between the energized tungsten electrode and a workpiece. The improvement comprises in combination with the tungsten electrode, a starting laser focused upon the tungsten electrode which to ignite the electrode heats a spot on the energized electrode sufficient for formation of a thermionic arc. Interference problems associated with high frequency starters are thus overcome. 3 figs.

  16. Tokamak ARC damage

    Energy Technology Data Exchange (ETDEWEB)

    Murray, J.G.; Gorker, G.E.

    1985-01-01

    Tokamak fusion reactors will have large plasma currents of approximately 10 MA with hundreds of megajoules stored in the magnetic fields. When a major plasma instability occurs, the disruption of the plasma current induces voltage in the adjacent conducting structures, giving rise to large transient currents. The induced voltages may be sufficiently high to cause arcing across sector gaps or from one protruding component to another. This report reviews a tokamak arcing scenario and provides guidelines for designing tokamaks to minimize the possibility of arc damage.

  17. Tokamak ARC damage

    International Nuclear Information System (INIS)

    Murray, J.G.; Gorker, G.E.

    1985-01-01

    Tokamak fusion reactors will have large plasma currents of approximately 10 MA with hundreds of megajoules stored in the magnetic fields. When a major plasma instability occurs, the disruption of the plasma current induces voltage in the adjacent conducting structures, giving rise to large transient currents. The induced voltages may be sufficiently high to cause arcing across sector gaps or from one protruding component to another. This report reviews a tokamak arcing scenario and provides guidelines for designing tokamaks to minimize the possibility of arc damage

  18. Utilización de las escorias de los hornos de arco eléctrico y de cuchara como materiales de construcción. // Use of slags from ladle and electric arc furnaces as construction materials.

    Directory of Open Access Journals (Sweden)

    R. Zaragoza Valdés

    2001-01-01

    Full Text Available La necesidad que tiene la humanidad de que las producciones sean cada día mas limpias, así como la que tiene el país del aumento dela rentabilidad de las empresas, hace necesario el estudio del uso de las escorias que se obtienen en la producción de acero, principalresidual de este tipo de producción. En el trabajo se estudia la utilización de la escoria del Horno de Arco Eléctrico (HAE comomaterial de relleno en la confección de bloques de hormigón para la construcción de edificaciones, sustituyendo la grava de granito.Se estudia, además, el uso de la escoria de los hornos cuchara (HC como sustituto del clinquer en la fabricación de cementosportland. Se obtienen resultados positivos para la protección del medio ambiente y la economía de la empresa metalúrgica.Palabras claves: producción de acero, escorias, medio ambiente, cementos, materiales para la construcción.________________________________________________________________________________Abstract:The existing necessity of clean productions as welll as the profitability of enterprises that the Cuban economy is demanding makes itnecessary to carry out a study of slags that constitute t he main residue of the steel production. This paper presents the use of slags comingfrom electric arc furnaces (EAF as a substitute for gravel in the production of concrete bricks. The use of slags coming from ladle furnaces(LF to replace clinker in the production of Portland Cement is also shown. Positive results are obtained such as the protection of theenvironment and the economic growth of the enterperise.Key words:Steel making, slags, environment protection, cement, construction materials.

  19. Structural, optical and electrical properties of N-doped ZnO thin films prepared by thermal oxidation of pulsed filtered cathodic vacuum arc deposited Zn{sub x}N{sub y} films

    Energy Technology Data Exchange (ETDEWEB)

    Erdogan, N.H.; Kara, K.; Ozdamar, H. [Physics Department, Cukurova University, 01330 Adana (Turkey); Kavak, H., E-mail: hkavak@cu.edu.tr [Physics Department, Cukurova University, 01330 Adana (Turkey); Esen, R. [Physics Department, Cukurova University, 01330 Adana (Turkey); Karaagac, H. [Physics Department, Middle East Technical University, 06531 Ankara (Turkey)

    2011-09-08

    Graphical abstract: Highlights: > Thermal oxidation of Zn{sub x}N{sub y} method is used to obtain N doped ZnO. > N acceptors in ZnO is not sufficiently activated at oxidation temperature below 350 deg. C. > Oxidation treatment at 450 deg. C activates more N acceptors in ZnO. > Oxidation treatment at high temperatures above 550 deg. C reduces the N concentration in the ZnO thin film. - Abstract: In this study, N-doped ZnO thin films were fabricated by oxidation of Zn{sub x}N{sub y} films. The Zn{sub x}N{sub y} thin films were deposited on glass substrates by pulsed filtered cathodic vacuum arc deposition (PFCVAD) using metallic zinc wire (99.999%) as a cathode target in pure nitrogen plasma. The influence of oxidation temperature, on the electrical, structural and optical properties of N-doped ZnO films was investigated. P-type conduction was achieved for the N-doped ZnO obtained at 450 deg. C by oxidation of Zn{sub x}N{sub y}, with a resistivity of 16.1 {Omega} cm, hole concentration of 2.03 x 10{sup 16} cm{sup -3} and Hall mobility of 19 cm{sup 2}/V s. X-ray photoelectron spectroscopy (XPS) analysis confirmed the incorporation of N into the ZnO films. X-ray diffraction (XRD) pattern showed that the films as-deposited and oxidized at 350 deg. C were amorphous. However, the oxidized films in air atmosphere at 450-550 deg. C were polycrystalline without preferential orientation. In room temperature photoluminescence (PL) spectra, an ultraviolet (UV) peak was seen for all the samples. In addition, a broad deep level emission was observed.

  20. Maintaining stability of standalone Micro-Grid by employing electrical and mechanical fault ride through techniques upon fixed speed wind generation systems

    International Nuclear Information System (INIS)

    Kamel, Rashad M.

    2013-01-01

    Highlights: • This paper presented two fault ride through techniques for fixed speed wind systems. • The first technique is implemented by inserting a series resistance with the terminals of wind generator. • Second technique is performed by adapting the gear ratio to spill some mechanical power. - Abstract: This study presents two different Fault Ride Through (FRT) techniques to keep and restore stability of Fixed Speed Wind Generation system (FSWGs) installed in standalone Micro-Grid (MG). The first technique is an electrical FRT and is implemented by inserting a series resistance with the terminals of FSWGs during fault to maintain reasonable value of terminal voltage and consequently help stability restoration. The second controller is a mechanical FRT controller and is performed by change the gear ratio of wind generation systems to spill part of extracted mechanical power and consequently improving stability issue. Obtained results proved that each controller able to maintain the stability of FSWGs under the most severe disturbance conditions (400 ms three phase fault at FSWGs terminals). The first controller is faster than the second controller in restoring FSWGs stability. Superior results and performances are obtained when the two FRT techniques are employed simultaneously. Without employing any one of the two FRT techniques, FSWGs is not able to maintain or restore its stability after fault clearing. Consequently, MG will lose one of its micro-sources and cannot keep its stability during the standalone mode, unless load shedding strategy is activated. The two proposed controllers are simple, effective, and economical attractive

  1. Sweden: Autonomous Reactivity Control (ARC) Systems

    International Nuclear Information System (INIS)

    Qvist, Staffan A.

    2015-01-01

    The next generation of nuclear energy systems must be licensed, constructed, and operated in a manner that will provide a competitively priced supply of energy, keeping in consideration an optimum use of natural resources, while addressing nuclear safety, waste, and proliferation resistance, and the public perception concerns of the countries in which those systems are deployed. These issues are tightly interconnected, and the implementation of passive and inherent safety features is a high priority in all modern reactor designs since it helps to tackle many of the issues at once. To this end, the Autonomous Reactivity Control (ARC) system was developed to ensure excellent inherent safety performance of Generation-IV reactors while having a minimal impact on core performance and economic viability. This paper covers the principles for ARC system design and analysis, the problem of ensuring ARC system response stability and gives examples of the impact of installing ARC systems in well-known fast reactor core systems. It is shown that even with a relatively modest ARC installation, having a near-negligible impact on core performance during standard operation, cores such as the European Sodium Fast Reactor (ESFR) can be made to survive any postulated unprotected transient without coolant boiling or fuel melting

  2. Sleep loss disrupts Arc expression in dentate gyrus neurons.

    Science.gov (United States)

    Delorme, James E; Kodoth, Varna; Aton, Sara J

    2018-04-07

    Sleep loss affects many aspects of cognition, and memory consolidation processes occurring in the hippocampus seem particularly vulnerable to sleep loss. The immediate-early gene Arc plays an essential role in both synaptic plasticity and memory formation, and its expression is altered by sleep. Here, using a variety of techniques, we have characterized the effects of brief (3-h) periods of sleep vs. sleep deprivation (SD) on the expression of Arc mRNA and Arc protein in the mouse hippocampus and cortex. By comparing the relative abundance of mature Arc mRNA with unspliced pre-mRNA, we see evidence that during SD, increases in Arc across the cortex, but not hippocampus, reflect de novo transcription. Arc increases in the hippocampus during SD are not accompanied by changes in pre-mRNA levels, suggesting that increases in mRNA stability, not transcription, drives this change. Using in situ hybridization (together with behavioral observation to quantify sleep amounts), we find that in the dorsal hippocampus, SD minimally affects Arc mRNA expression, and decreases the number of dentate gyrus (DG) granule cells expressing Arc. This is in contrast to neighboring cortical areas, which show large increases in neuronal Arc expression after SD. Using immunohistochemistry, we find that Arc protein expression is also differentially affected in the cortex and DG with SD - while larger numbers of cortical neurons are Arc+, fewer DG granule cells are Arc+, relative to the same regions in sleeping mice. These data suggest that with regard to expression of plasticity-regulating genes, sleep (and SD) can have differential effects in hippocampal and cortical areas. This may provide a clue regarding the susceptibility of performance on hippocampus-dependent tasks to deficits following even brief periods of sleep loss. Copyright © 2018. Published by Elsevier Inc.

  3. Insulation Coordination of Arcing Horns on HVDC Electrode Lines: Protection Performance Evaluation, Influence Factors and Improvement Method

    Directory of Open Access Journals (Sweden)

    Xiandong Li

    2018-02-01

    Full Text Available Arcing horns are widely used in high voltage overhead lines to protect insulator strings from being destroyed by the free burning arcs caused by lightening faults. In this paper, we focus on the insulation coordination of arcing horns on the electrode lines of a 5000 MW, ±800 kV high voltage direct current (HVDC system. The protection performance of arcing horns are determined by the characteristics of not only the external system but also the fault arc. Therefore, the behaviors and characteristics of long free burning arcs are investigated by the experiments at first. In order to evaluate the protection performance of arcing horns, the static stability criterion U-I characteristic method is introduced. The influence factors on the protection performance of arcing horns are analyzed theoretically. Finally, the improvement methods for the protection performance of arcing horns are proposed, and the diversified configuration strategy of arcing horns is recommended for cost saving.

  4. ALICE - ARC integration

    OpenAIRE

    Anderlik, Csaba; Gregersen, Anders Rhod; Kleist, Josva; Peters, Andreas; Siaz, Pablo

    2007-01-01

    AliEn or Alice Environment is the Gridware developed and used within the ALICE collaboration for storing and processing data in a distributed manner. ARC (Advanced Resource Connector) is the Grid middleware deployed across the Nordic countries and gluing together the resources within the Nordic Data Grid Facility (NDGF). In this paper we will present our approach to integrate AliEn and ARC, in the sense that ALICE data management and job processing can be carried out on the NDGF infrastructur...

  5. Investigations into electrical discharges in gases

    CERN Document Server

    Klyarfel'D, B N

    2013-01-01

    Investigations into Electrical Discharges in Gases is a compilation of scientific articles that covers the advances in the investigation of the fundamental processes occurring in electrical discharges in gases and vapors. The book details the different aspects of the whole life cycle of an arc, which include the initiation of a discharge, its transition into an arc, the lateral spread of the arc column, and the recovery of electric strength after extinction of an arc. The text also discusses the methods for the dynamic measurement of vapor density in the vicinity of electrical discharges, alon

  6. Enhanced electrical stability of nitrate ligand-based hexaaqua complexes solution-processed ultrathin a-IGZO transistors

    Science.gov (United States)

    Choi, C.; Baek, Y.; Lee, B. M.; Kim, K. H.; Rim, Y. S.

    2017-12-01

    We report solution-processed, amorphous indium–gallium–zinc-oxide-based (a-IGZO-based) thin-film transistors (TFTs). Our proposed solution-processed a-IGZO films, using a simple spin-coating method, were formed through nitrate ligand-based metal complexes, and they were annealed at low temperature (250 °C) to achieve high-quality oxide films and devices. We investigated solution-processed a-IGZO TFTs with various thicknesses, ranging from 4 to 16 nm. The 4 nm-thick TFT films had smooth morphology and high-density, and they exhibited excellent performance, i.e. a high saturation mobility of 7.73  ±  0.44 cm2 V‑1 s‑1, a sub-threshold swing of 0.27 V dec‑1, an on/off ratio of ~108, and a low threshold voltage of 3.10  ±  0.30 V. However, the performance of the TFTs degraded as the film thickness was increased. We further performed positive and negative bias stress tests to examine their electrical stability, and it was noted that the operating behavior of the devices was highly stable. Despite a small number of free charges, the high performance of the ultrathin a-IGZO TFTs was attributed to the small effect of the thickness of the channel, low bulk resistance, the quality of the a-IGZO/SiO2 interface, and high film density.

  7. Balanced plasticity and stability of the electrical properties of a molluscan modulatory interneuron after classical conditioning: a computational study

    Directory of Open Access Journals (Sweden)

    Dimitris Vavoulis

    2010-05-01

    Full Text Available The Cerebral Giant Cells (CGCs are a pair of identified modulatory interneurons in the Central Nervous System of the pond snail Lymnaea stagnalis with an important role in the expression of both unconditioned and conditioned feeding behavior. Following single-trial food-reward classical conditioning, the membrane potential of the CGCs becomes persistently depolarized. This depolarization contributes to the conditioned response by facilitating sensory cell to command neuron synapses, which results in the activation of the feeding network by the conditioned stimulus. Despite the depolarization of the membrane potential, which enables the CGGs to play a key role in learning-induced network plasticity, there is no persistent change in the tonic firing rate or shape of the action potentials, allowing these neurons to retain their normal network function in feeding. In order to understand the ionic mechanisms of this novel combination of plasticity and stability of intrinsic electrical properties, we first constructed and validated a Hodgkin-Huxley-type model of the CGCs. We then used this model to elucidate how learning-induced changes in a somal persistent sodium and a delayed rectifier potassium current lead to a persistent depolarization of the CGCs whilst maintaining their firing rate. Including in the model an additional increase in the conductance of a high-voltage-activated calcium current allowed the spike amplitude and spike duration also to be maintained after conditioning. We conclude therefore that a balanced increase in three identified conductances is sufficient to explain the electrophysiological changes found in the CGCs after classical conditioning.

  8. A simplified numerical analysis of helical instabilities of arcs in axial magnetic field

    International Nuclear Information System (INIS)

    Gong Ye; Lu Wenyan; Liu Jinyuan; Zheng Shu; Gong Jiquan

    2002-01-01

    The energy equations were simplified by the correct electrostatic ordering under electrostatic approximation. The effects of the external axial magnetic field, the current profiles and arc currents on the helical instabilities of arcs were studied by using numerical method. In the presence of the external magnetic field, numerical results show that when the current profile of an arc column is the uniform distribution, the short wavelength perturbation can be stabilized by positive direction magnetic field, whereas the long wavelength perturbation can be stabilized by reverse magnetic field. When the current profile of an arc column has a parabolic distribution, in the short wavelength perturbation case, the effect of positive direction magnetic field on the arc stability is very small. However, its stabilizing effect is enhanced for the long wavelength perturbation. The intermediate and long wavelength perturbations can also be stabilized by reverse magnetic field

  9. Application of Steenbeck's minimum principle for three-dimensional modelling of DC arc plasma torches

    CERN Document Server

    Li He Ping; Chen, X

    2003-01-01

    In this paper, physical/mathematical models for the three-dimensional, quasi-steady modelling of the plasma flow and heat transfer inside a non-transferred DC arc plasma torch are described in detail. The Steenbeck's minimum principle (Finkelnburg W and Maecker H 1956 Electric arcs and thermal plasmas Encyclopedia of Physics vol XXII (Berlin: Springer)) is employed to determine the axial position of the anode arc-root at the anode surface. This principle postulates a minimum arc voltage for a given arc current, working gas flow rate, and torch configuration. The modelling results show that the temperature and flow fields inside the DC non-transferred arc plasma torch show significant three-dimensional features. The predicted anode arc-root attachment position and the arc shape by employing Steenbeck's minimum principle are reasonably consistent with experimental observations. The thermal efficiency and the torch power distribution are also calculated in this paper. The results show that the thermal efficiency...

  10. Surface breakdown igniter for mercury arc devices

    Science.gov (United States)

    Bayless, John R.

    1977-01-01

    Surface breakdown igniter comprises a semiconductor of medium resistivity which has the arc device cathode as one electrode and has an igniter anode electrode so that when voltage is applied between the electrodes a spark is generated when electrical breakdown occurs over the surface of the semiconductor. The geometry of the igniter anode and cathode electrodes causes the igniter discharge to be forced away from the semiconductor surface.

  11. Metal-doped diamond-like carbon films synthesized by filter-arc deposition

    International Nuclear Information System (INIS)

    Weng, K.-W.; Chen, Y.-C.; Lin, T.-N.; Wang, D.-Y.

    2006-01-01

    Diamond-like carbon (DLC) thin films are extensively utilized in the semiconductor, electric and cutting machine industries owing to their high hardness, high elastic modulus, low friction coefficients and high chemical stability. DLC films are prepared by ion beam-assisted deposition (BAD), sputter deposition, plasma-enhanced chemical vapor deposition (PECVD), cathodic arc evaporation (CAE), and filter arc deposition (FAD). The major drawbacks of these methods are the degraded hardness associated with the low sp 3 /sp 2 bonding ratio, the rough surface and poor adhesion caused by the presence of particles. In this study, a self-developed filter arc deposition (FAD) system was employed to prepare metal-containing DLC films with a low particle density. The relationships between the DLC film properties, such as film structure, surface morphology and mechanical behavior, with variation of substrate bias and target current, are examined. Experimental results demonstrate that FAD-DLC films have a lower ratio, suggesting that FAD-DLC films have a greater sp 3 bonding than the CAE-DLC films. FAD-DLC films also exhibit a low friction coefficient of 0.14 and half of the number of surface particles as in the CAE-DLC films. Introducing a CrN interfacial layer between the substrate and the DLC films enables the magnetic field strength of the filter to be controlled to improve the adhesion and effectively eliminate the contaminating particles. Accordingly, the FAD system improves the tribological properties of the DLC films

  12. ALICE-ARC integration

    International Nuclear Information System (INIS)

    Anderlik, C; Gregersen, A R; Kleist, J; Peters, A; Saiz, P

    2008-01-01

    AliEn or Alice Environment is the Grid middleware developed and used within the ALICE collaboration for storing and processing data in a distributed manner. ARC (Advanced Resource Connector) is the Grid middleware deployed across the Nordic countries and gluing together the resources within the Nordic Data Grid Facility (NDGF). In this paper we will present our approach to integrate AliEn and ARC, in the sense that ALICE data management and job processing can be carried out on the NDGF infrastructure, using the client tools available in AliEn. The inter-operation has two aspects, one is the data management part and the second the job management aspect. The first aspect was solved by using dCache across NDGF to handle data. Therefore, we will concentrate on the second part. Solving it, was somewhat cumbersome, mainly due to the different computing models employed by AliEn and ARC. AliEN uses an Agent based pull model while ARC handles jobs through the more 'traditional' push model. The solution comes as a module implementing the functionalities necessary to achieve AliEn job submission and management to ARC enabled sites

  13. Consolidating NASA's Arc Jets

    Science.gov (United States)

    Balboni, John A.; Gokcen, Tahir; Hui, Frank C. L.; Graube, Peter; Morrissey, Patricia; Lewis, Ronald

    2015-01-01

    The paper describes the consolidation of NASA's high powered arc-jet testing at a single location. The existing plasma arc-jet wind tunnels located at the Johnson Space Center were relocated to Ames Research Center while maintaining NASA's technical capability to ground-test thermal protection system materials under simulated atmospheric entry convective heating. The testing conditions at JSC were reproduced and successfully demonstrated at ARC through close collaboration between the two centers. New equipment was installed at Ames to provide test gases of pure nitrogen mixed with pure oxygen, and for future nitrogen-carbon dioxide mixtures. A new control system was custom designed, installed and tested. Tests demonstrated the capability of the 10 MW constricted-segmented arc heater at Ames meets the requirements of the major customer, NASA's Orion program. Solutions from an advanced computational fluid dynamics code were used to aid in characterizing the properties of the plasma stream and the surface environment on the calorimeters in the supersonic flow stream produced by the arc heater.

  14. ALICE—ARC integration

    Science.gov (United States)

    Anderlik, C.; Gregersen, A. R.; Kleist, J.; Peters, A.; Saiz, P.

    2008-07-01

    AliEn or Alice Environment is the Grid middleware developed and used within the ALICE collaboration for storing and processing data in a distributed manner. ARC (Advanced Resource Connector) is the Grid middleware deployed across the Nordic countries and gluing together the resources within the Nordic Data Grid Facility (NDGF). In this paper we will present our approach to integrate AliEn and ARC, in the sense that ALICE data management and job processing can be carried out on the NDGF infrastructure, using the client tools available in AliEn. The inter-operation has two aspects, one is the data management part and the second the job management aspect. The first aspect was solved by using dCache across NDGF to handle data. Therefore, we will concentrate on the second part. Solving it, was somewhat cumbersome, mainly due to the different computing models employed by AliEn and ARC. AliEN uses an Agent based pull model while ARC handles jobs through the more 'traditional' push model. The solution comes as a module implementing the functionalities necessary to achieve AliEn job submission and management to ARC enabled sites.

  15. Arc generation from sputtering plasma-dielectric inclusion interactions

    CERN Document Server

    Wickersham, C E J; Fan, J S

    2002-01-01

    Arcing during sputter deposition and etching is a significant cause of particle defect generation during device fabrication. In this article we report on the effect of aluminum oxide inclusion size, shape, and orientation on the propensity for arcing during sputtering of aluminum targets. The size, shape, and orientation of a dielectric inclusion plays a major role in determining the propensity for arcing and macroparticle emission. In previous studies we found that there is a critical inclusion size required for arcing to occur. In this article we used high-speed videos, electric arc detection, and measurements of particle defect density on wafers to study the effect of Al sub 2 O sub 3 inclusion size, shape, and orientation on arc rate, intensity, and silicon wafer particle defect density. We found that the cross-sectional area of the inclusion exposed to the sputtering plasma is the critical parameter that determines the arc rate and rate of macroparticle emission. Analysis of the arc rate, particle defect...

  16. Arc protein: a flexible hub for synaptic plasticity and cognition.

    Science.gov (United States)

    Nikolaienko, Oleksii; Patil, Sudarshan; Eriksen, Maria Steene; Bramham, Clive R

    2017-09-07

    Mammalian excitatory synapses express diverse types of synaptic plasticity. A major challenge in neuroscience is to understand how a neuron utilizes different types of plasticity to sculpt brain development, function, and behavior. Neuronal activity-induced expression of the immediate early protein, Arc, is critical for long-term potentiation and depression of synaptic transmission, homeostatic synaptic scaling, and adaptive functions such as long-term memory formation. However, the molecular basis of Arc protein function as a regulator of synaptic plasticity and cognition remains a puzzle. Recent work on the biophysical and structural properties of Arc, its protein-protein interactions and post-translational modifications have shed light on the issue. Here, we present Arc protein as a flexible, multifunctional and interactive hub. Arc interacts with specific effector proteins in neuronal compartments (dendritic spines, nuclear domains) to bidirectionally regulate synaptic strength by distinct molecular mechanisms. Arc stability, subcellular localization, and interactions are dictated by synaptic activity and post-translational modification of Arc. This functional versatility and context-dependent signaling supports a view of Arc as a highly specialized master organizer of long-term synaptic plasticity, critical for information storage and cognition. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. On the problem of turbulent arcs modelling

    International Nuclear Information System (INIS)

    Yas'ko, O.I.

    1998-01-01

    A new hypothesis is proposed which considers mass as a charge which produces a special field during its movement likewise the electric charge creates magnetic one. This approach throws new light on vortexes formation since interaction of moving mass with the considered field exerts swirling effect. Some aspects of turbulence in flows near walls and in blown electric arc discharge were considered to validate the hypothesis in the cases of cold and high-temperature flows. The theoretical results are found to comply with experiment well. (author)

  18. Arcs from gravitational lensing

    Science.gov (United States)

    Grossman, Scott A.; Narayan, Ramesh

    1988-01-01

    The proposal made by Paczynski (1987) that the arcs of blue light found recently in two cluster cores are gravitationally lensed elongated images of background galaxies is investigated. It is shown that lenses that are circularly symmetric in projection produce pairs of arcs, in conflict with the observations. However, more realistic asymmetric lenses produce single arcs, which can become as elongated as the observed ones whenever the background galaxy is located on or close to a cusp caustic. Detailed computer simulations of lensing by clusters using a reasonable model of the mass distribution are presented. Elongated and curved lensed images longer than 10 arcsec occur in 12 percent of the simulated clusters. It is concluded that the lensing hypothesis must be taken seriously.

  19. ALICE - ARC integration

    DEFF Research Database (Denmark)

    Anderlik, Csaba; Gregersen, Anders Rhod; Kleist, Josva

    Data Grid Facility (NDGF). In this paper we will present our approach to integrate AliEn and ARC, in the sense that ALICE data management and job processing can be carried out on the NDGF infrastructure, using the client tools available in AliEn. The interoperation has two aspects, one is the data...... management part and the second the job management aspect. The first aspect was solved by using dCache across NDGF to handle data. dCache provides support for several data management tools (among them for xrootd the tools used by AliEn) using the so called "doors". Therefore, we will concentrate on the second...... part. Solving it, was somewhat cumbersome, mainly due to the different computing models employed by AliEn and ARC. AliEN uses an Agent based pull model while ARC handles jobs through the more "traditional" push model. The solution comes as a module implementing the functionalities necessary to achieve...

  20. Three-dimensional numerical modelling of a magnetically deflected dc transferred arc in argon

    CERN Document Server

    Blais, A; Boulos, M I

    2003-01-01

    The aim of this work is to develop a numerical model for the deflection of dc transferred arcs using an external magnetic field as a first step into the modelling of industrial arc furnaces. The arc is deflected by the use of a conductor aligned parallel to the arc axis through which flows an electric current. The model is validated by comparing the results of axisymmetric calculations to modelling results from the scientific literature. The present model is found to be a good representation of the electric dc arc as differences with the literature are easily explained by model parameters such as the critical boundary conditions at the electrodes. Transferred arc cases exhibit the expected behaviour as the temperature T, the velocity v-vector and the electrical potential drop DELTA phi all increase with the arc current I and the argon flow rate Q. Three-dimensional geometry is implemented, enabling one to numerically deflect the arc. For the deflected arc cases, the deflection increases with the arc current I...

  1. Vacuum Arc Ion Sources

    CERN Document Server

    Brown, I.

    2013-12-16

    The vacuum arc ion source has evolved into a more or less standard laboratory tool for the production of high-current beams of metal ions, and is now used in a number of different embodiments at many laboratories around the world. Applications include primarily ion implantation for material surface modification research, and good performance has been obtained for the injection of high-current beams of heavy-metal ions, in particular uranium, into particle accelerators. As the use of the source has grown, so also have the operational characteristics been improved in a variety of different ways. Here we review the principles, design, and performance of vacuum arc ion sources.

  2. Arc Heated Scramjet Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Arc Heated Scramjet Test Facility is an arc heated facility which simulates the true enthalpy of flight over the Mach number range of about 4.7 to 8 for free-jet...

  3. Theoretical Investigation of a Hot Refractory Anode Vacuum Arc

    International Nuclear Information System (INIS)

    Beilis, I.I.; Boxman, R.L.; Goldsmith, S.

    1999-01-01

    The two principal modes of the vacuum arc arc the multi-cathode spot and the anode spot vacuum arc discharges. In both cases the current is conducted in plasma that is generated on relatively small areas on the relevant electrode surface. The hot anode vacuum arc (HAVA) is another mode of the vacuum arc in which the plasma is produced by material evaporation over the whole surface of a high temperature anode heated by the arc itself. In the present work, a model of a new type of the HAVA, recently discovered in the Electrical Discharges and Plasma Laboratory of TAU, is considered. In this mode of the HAVA the anode is made of a thermally isolated refractory material (graphite), whereas the water cooled cathode is fabricated from a more volatile material (copper). The discharge starts in the multi-cathode spot mode and after a transition period, during which the anode is heated by the arc, re-evaporated cathode material is released from the hot anode surface and becomes the main source of the arc plasma. At steady state, anode temperature exceeds a certain critical value. No evaporation of anode refractory material occurs during arc operation. This arc mode is labeled Hot Refractory Anode Vacuum Arc (HRAVA). The theoretical description of the HRAVA is accomplished by a plasma model that includes equations of mass, momentum, energy, and electrical current conservation, and by an anode thermal model that describes the anode thermal balance. The plasma model also considers radial expansion of the plasma from the interelectrode region. A self-consistent solution of the plasma and anode models was obtained. Plasma electron temperature, plasma density, plasma energy flux to the anode, and anode temperature distribution were calculated for several arc currents in the range 175 - 500 A. In the steady-state arc operation, anode surface temperature was calculated to be in the range 1800 - 2600 degree K, electron temperature is about 1 eV, effective anode voltage is about 6 V

  4. Gas tungsten arc welder

    Science.gov (United States)

    Christiansen, D.W.; Brown, W.F.

    A welder for automated closure of fuel pins by a gas tungsten arc process in which a rotating length of cladding is positioned adjacent a welding electrode in a sealed enclosure. An independently movable axial grinder is provided in the enclosure for refurbishing the used electrode between welds.

  5. ALICE: ARC integration

    CERN Document Server

    Anderlik, C; Kleist, J; Peters, A; Saiz, P

    2008-01-01

    AliEn or Alice Environment is the Grid middleware developed and used within the ALICE collaboration for storing and processing data in a distributed manner. ARC (Advanced Resource Connector) is the Grid middleware deployed across the Nordic countries and gluing together the resources within the Nordic Data Grid Facility (NDGF). In this paper we will present our approach to integrate AliEn and ARC, in the sense that ALICE data management and job processing can be carried out on the NDGF infrastructure, using the client tools available in AliEn. The inter-operation has two aspects, one is the data management part and the second the job management aspect. The first aspect was solved by using dCache across NDGF to handle data. Therefore, we will concentrate on the second part. Solving it, was somewhat cumbersome, mainly due to the different computing models employed by AliEn and ARC. AliEN uses an Agent based pull model while ARC handles jobs through the more 'traditional' push model. The solution comes as a modu...

  6. Thermal Arc Spray Overview

    Science.gov (United States)

    Hafiz Abd Malek, Muhamad; Hayati Saad, Nor; Kiyai Abas, Sunhaji; Mohd Shah, Noriyati

    2013-06-01

    Usage of protective coating for corrosion protection was on highly demand during the past decade; and thermal spray coating played a major part during that time. In recent years, the thermal arc spray coating becomes a popular coating. Many big players in oil and gas such as PETRONAS, EXXON MOBIL and SHELL in Malaysia tend to use the coating on steel structure as a corrosion protection. Further developments in coating processes, the devices, and raw materials have led to expansion of functional coatings and applications scope from conventional coating to specialized industries. It is widely used because of its ability to withstand high process temperature, offer advantages in efficiency, lower cost and acts as a corrosion protection. Previous research also indicated that the thermal arc spray offers better coating properties compared to other methods of spray. This paper reviews some critical area of thermal spray coating by discussing the process/parameter of thermal arc spray technology and quality control of coating. Coating performance against corrosion, wear and special characteristic of coating are also described. The field application of arc spray technology are demonstrated and reviewed.

  7. ALICE-ARC integration

    DEFF Research Database (Denmark)

    Anderlik, Csaba; Gregersen, Anders Rhod; Kleist, Josva

    2008-01-01

    Data Grid Facility (NDGF). In this paper we will present our approach to integrate AliEn and ARC, in the sense that ALICE data management and job processing can be carried out on the NDGF infrastructure, using the client tools available in AliEn. The interoperation has two aspects, one is the data...

  8. Calculation of the Arc Velocity Along the Polluted Surface of Short Glass Plates Considering the Air Effect

    Directory of Open Access Journals (Sweden)

    Tao Yuan

    2012-03-01

    Full Text Available To investigate the microphysics mechanism and the factors that influence arc development along a polluted surface, the arc was considered as a plasma fluid. Based on the image method and the collision ionization theory, the electric field of the arc needed to maintain movement with different degrees of pollution was calculated. According to the force of the charged particle in an arc plasma stressed under an electric field, a calculation model of arc velocity, which is dependent on the electric field of the arc head that incorporated the effects of airflow around the electrode and air resistance is presented. An experiment was carried out to measure the arc velocity, which was then compared with the calculated value. The results of the experiment indicated that the lighter the pollution is, the larger the electric field of the arc head and arc velocity is; when the pollution is heavy, the effect of thermal buoyancy that hinders arc movement increases, which greatly reduces the arc velocity.

  9. Plasma drifts associated with a system of sun-aligned arcs in the polar cap

    International Nuclear Information System (INIS)

    Mende, S.B.; Doolittle, J.H.; Robinson, R.M.; Vondrak, R.R.; Rich, F.J.

    1988-01-01

    A series of four sun-aligned arcs passed over Sondre Stromfjord, Greenland, on the night of the 17th and 18th of February, 1985. Observations of these arcs were made using the Sondrestrom incoherent scatter radar and an intensified all-sky imaging TV system that was operated at the radar site. The first of the four arcs crossed the Sondre Stromfjord meridian just before local midnight moving westward, and the other three arcs followed at approximately half-hour intervals. When we account for the earth's rotation, the arc drift in an inertial frame was eastward, or dusk to dawn. The half-hour interval between meridian crossings of the arcs implies that the mean spacing between the arcs was 180 km. A Defense Meteorological Satellite Program (DMSP) F6 satellite pass at 0110 UT revealed the presence of highly structured electron and ion precipitation throughout the polar cap. The DMSP visible imager detected a single, sun-aligned arc associated with the largest peak in precipitating electron flux. This arc was also observed at Thule, Greenland, with an intensified film camera. These observations suggest that at least one of the arcs that were observed at Sondre Stromfjord extended across a large part of the polar cap. The radar at Sondre Stromfjord measured electron density and ion drift velocities associated with the four arcs. The radar drift measurements were superimposed on the all-sky video images to determine the location of the measurements relative to the arcs. Plasma drifts outside the arcs were found to be both sunward and antisunward, while within the arcs the drifts were predominantly antisunward. The variability of the drifts in the direction parallel to the arcs indicates that the electric fields were highly structured even though the configuration and motion of the arcs were well behaved

  10. Measurement and analysis methods for flicker at arc furnace installations

    OpenAIRE

    2012-01-01

    M.Ing. \\Vith electrical power networks expanding beyond their original design limits and the various non-linear loads on the network, power quality has become an important issue in electrical engineering. Some of the largest non-linear loads on the power network are arc furnaces used to melt various metal orrs and scrap metal. In this study the focus is on fliCker as a power quality issue and more specifically the measurement and analysis methods of flicker at arc furnace installations. By...

  11. Arc melter demonstration baseline test results

    Energy Technology Data Exchange (ETDEWEB)

    Soelberg, N.R.; Chambers, A.G.; Anderson, G.L.; Oden, L.L.; O`Connor, W.K.; Turner, P.C.

    1994-07-01

    This report describes the test results and evaluation for the Phase 1 (baseline) arc melter vitrification test series conducted for the Buried Waste Integrated Demonstration program (BWID). Phase 1 tests were conducted on surrogate mixtures of as-incinerated wastes and soil. Some buried wastes, soils, and stored wastes at the INEL and other DOE sites, are contaminated with transuranic (TRU) radionuclides and hazardous organics and metals. The high temperature environment in an electric arc furnace may be used to process these wastes to produce materials suitable for final disposal. An electric arc furnace system can treat heterogeneous wastes and contaminated soils by (a) dissolving and retaining TRU elements and selected toxic metals as oxides in the slag phase, (b) destroying organic materials by dissociation, pyrolyzation, and combustion, and (c) capturing separated volatilized metals in the offgas system for further treatment. Structural metals in the waste may be melted and tapped separately for recycle or disposal, or these metals may be oxidized and dissolved into the slag. The molten slag, after cooling, will provide a glass/ceramic final waste form that is homogeneous, highly nonleachable, and extremely durable. These features make this waste form suitable for immobilization of TRU radionuclides and toxic metals for geologic timeframes. Further, the volume of contaminated wastes and soils will be substantially reduced in the process.

  12. Light beams interaction with highly effective holographic diffraction structure formed in polymer-stabilized liquid crystal under the impact of arbitrarily spatially inhomogeneous electric field

    Science.gov (United States)

    Sharangovich, Sergey N.; Semkin, Artem O.

    2016-11-01

    In this work we developed the analytical model of highly effective diffraction on holographic diffraction structures in polymer-stabilized liquid crystals (PSLC) under the impact of arbitrarily inhomogeneous external electric field. The exact self-consistent analytical solutions are obtained by solving the system of coupled-wave equations describing the diffraction process by Riemann's method. They takes into account the electrically-induced phase mismatch changing's inhomogeneity caused by the strong adhesion between liquid crystal molecules and bounding surfaces. According to the obtained relations, numerical simulation of the diffraction characteristics under the influence of external fields with different form of spatial inhomogeneity was made. The simulation results show qualitative compliance with the earlier obtained results.

  13. Oxygen flow effects on electrical properties, stability, and density of states of amorphous In-Ga-Zn-O thin-film transistors

    Science.gov (United States)

    Lee, Yong-Su; Kai-Hsiang Yu, Eric; Shim, Dong-Hwan; Kong, Hyang-Shik; Bie, Linsen; Kanicki, Jerzy

    2014-12-01

    To investigate the origin of threshold voltage (Vth) shift of amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs), a combination of bias-temperature stress (BTS) and multi-frequency capacitance-voltage (C-V) measurements were used to evaluate the impact of oxygen partial pressure (PO2) during a-IGZO deposition on TFT electrical properties, electrical stability, and density of states (DOS). The extracted sub-gap DOS was decomposed into exponential bandtail states and Gaussian-like deep-gap states. The peak density of Gaussian-like states is larger for higher PO2. We conclude that the Gaussian-like states are excess/weakly-bonded oxygen in the form of O0 or O1- ions acting as acceptor-like states and are at the origin of TFT threshold voltage shift during positive BTS.

  14. Study on Differential Regenerative Braking Torque Control to Increase the Stability of the Small Electric Vehicle with Four In-Wheel Motors

    Directory of Open Access Journals (Sweden)

    Ali N. M.

    2017-01-01

    Full Text Available Based on the advantages of the electric motor such as fast and precise torque response, the performance of the electric vehicle (EV can be improved. During braking or driving on the cornering, the vehicle will over steer or under steer if a car turns by more or less than the amount commanded by the driver. To improve the stability of the small EV with four in-wheel motors, the differential regenerative braking torque control is proposed. In this system, the regenerative braking torque at each wheel will be controlled individually based on the value of slip ratio. If the slip ratio is greater than the optimum value, the regenerative brake will turn off. In this situation, the electric motor will not produce the regenerative braking torque. Conversely, if the slip ratio lower than the optimum value, the regenerative brake will turn on and the electric motor will generate the regenerative braking torque. In the numerical analysis, to investigate the effectiveness of the proposed model, the road condition is set to an icy road on the left tire and dry asphalt on the right tire. From the simulation results, the differential regenerative braking torque control can prevent the tire from lock-up and avoid the vehicle from skidding.

  15. An Overlooked Source of Auroral Arc Field-Aligned Current

    Science.gov (United States)

    Knudsen, D. J.

    2017-12-01

    The search for the elusive generator of quiet auroral arcs often focuses on magnetospheric pressure gradients, based on the static terms in the so-called Vaslyiunas equation [Vasyliunas, in "Magneospheric Currents", Geophysical Monograph 28, 1984]. However, magnetospheric pressure gradient scale sizes are much larger than the width of individual auroral arcs. This discrepancy was noted by Atkinson [JGR, 27, p4746, 1970], who proposed that the auroral arcs are fed instead by steady-state polarization currents, in which large-scale convection across quasi-static electric field structures leads to an apparent time dependence in the frame co-moving with the plasma, and therefore to the generation of ion polarization currents. This mechanism has been adopted by a series of authors over several decades, relating to studies of the ionospheric feedback instability, or IFI. However, the steady-state polarization current mechanism does not require the IFI, nor even the ionsophere. Specifically, any quasi-static electric field structure that is stationary relative to large-scale plasma convection is subject to the generation this current. This talk demonstrates that assumed convection speeds of the order of a 100 m/s across typical arc fields structures can lead to the generation FAC magintudes of several μA/m2, typical of values observed at the ionospheric footpoint of auoral arcs. This current can be viewed as originating within the M-I coupling medium, along the entire field line connecting an auroral arc to its root in the magnetosphere.

  16. Arc - An endogenous neuronal retrovirus?

    Science.gov (United States)

    Shepherd, Jason D

    2018-05-01

    The neuronal gene Arc is essential for long-lasting information storage in the mammalian brain and has been implicated in various neurological disorders. However, little is known about Arc's evolutionary origins. Recent studies suggest that mammalian Arc originated from a vertebrate lineage of Ty3/gypsy retrotransposons, which are also ancestral to retroviruses. In particular, Arc contains homology to the Gag polyprotein that forms the viral capsid and is essential for viral infectivity. This surprising connection raises the intriguing possibility that Arc may share molecular characteristics of retroviruses. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Consumibles para soldadura por arco eléctrico: algunos desarrollos recientes Consumíveis para soldagem por arco elétrico: alguns desenvolvimentos recentes Consumables for electric arc welding: some recent developments

    Directory of Open Access Journals (Sweden)

    Estela Silvia Surian

    2013-03-01

    Full Text Available En este trabajo se comentan algunos de los últimos desarrollos en consumibles para soldadura por arco eléctrico. No es intención de la autora presentar un estado del arte sobre el tema sino remarcar las tendencias en algunas áreas del desarrollo de consumibles, como ser: la cuestión del hidrógeno difusible, los mejoramientos de alambres de unión del sistema C-Mn y la soldadura de aceros de alta resistencia y para servicio a alta temperatura 9Cr. También se mencionan las actividades actuales en estandarización de consumibles. La autora considera que el desarrollo está muy activo y en una etapa de generación de nuevos consumibles para hacer posible la soldadura de nuevos materiales y de sofisticación de los ya existentes, con el objetivo de generar cada vez mayor eficiencia y calidad en la construcción soldada junto con una actitud más amigable con el medio ambiente.Em este trabalho se comentam alguns dos últimos desenvolvimentos em consumíveis para soldagem por arco elétrico. Não é a intenção de a autora apresentar um estado da arte sobre o tema, mas remarcar as tendências em algumas áreas do desenvolvimento de consumíveis, como são: a questão do hidrogênio, os melhoramentos de arames de união do sistema C-Mn e a soldagem de aços de alta resistência e para serviço a alta temperatura 9Cr. Também são mencionadas as atividades em estandardização de consumíveis. O autor considera que o desenvolvimento está muito ativo e em uma etapa de geração de novos consumíveis para fazer possível a soldagem de novos materiais y de sofisticação dos já existentes, com o objetivo de aumentar a eficiência e a qualidade na construção soldada junto com uma atitude mais amigável com o meio ambiente.In this work some of the last developments in consumables for electric arc welding are commented. It is not the intention of the author to present a state of the art on this subject but to remark some areas of consumable

  18. Quality stability and sensory attributes of apple juice processed by thermosonication, pulsed electric field and thermal processing.

    Science.gov (United States)

    Sulaiman, Alifdalino; Farid, Mohammed; Silva, Filipa Vm

    2017-04-01

    Worldwide, apple juice is the second most popular juice, after orange juice. It is susceptible to enzymatic browning spoilage by polyphenoloxidase, an endogenous enzyme. In this study, Royal Gala apple juice was treated by thermosonication (TS: 1.3 W/mL, 58 ℃, 10 min), pulsed electric field (PEF: 24.8 kV/cm, 60 pulses, 169 µs treatment time, 53.8 ℃) and heat (75 ℃, 20 min) and stored at 3.0 ℃ and 20.0 ℃ for 30 days. A sensory analysis was carried out after processing. The polyphenoloxidase activity, antioxidant activity and total color difference of the apple juice were determined before and after processing and during storage. The sensory analysis revealed that thermosonication and pulsed electric field juices tasted differently from the thermally treated juice. Apart from the pulsed electric field apple juice stored at room temperature, the processed juice was stable during storage, since the pH and soluble solids remained constant and fermentation was not observed. Polyphenoloxidase did not reactivate during storage. Along storage, the juices' antioxidant activity decreased and total color difference increased (up to 6.8). While the antioxidant activity increased from 86 to 103% with thermosonication and was retained after pulsed electric field, thermal processing reduced it to 67%. The processing increased the total color difference slightly. No differences in the total color difference of the juices processed by the three methods were registered after storage. Thermosonication and pulsed electric field could possibly be a better alternative to thermal preservation of apple juice, but refrigerated storage is recommended for pulsed electric field apple juice.

  19. Quantitative evaluation method of arc sound spectrum based on sample entropy

    Science.gov (United States)

    Yao, Ping; Zhou, Kang; Zhu, Qiang

    2017-08-01

    Arc sound analysis is an effective way to evaluate the stability of the arc welding process. Current methods cannot effectively quantify the disorder of the process. By studying the characteristics of the arc sound signal, we found that low frequency random mutation of arc sound power resulted from unstable factors, such as splashes or short circuits, increased the complexity and randomness of the arc sound signals. Then the arc sound signals were visualized on time-frequency interface by means of spectrogram, and it was found that the max power spectral density (PSD) distribution of spectrogram was closely related to the stability of arc welding process. Moreover, a method based on sample entropy was proposed to further quantify the relation. Finally, considering the factors such as averages of max PSD and the standard deviations of sample entropy, a compound quantitative evaluation indicator, arc sound sample entropy (ASSE), which can avoid the influence of different parameters on the quantitative results, was proposed, so that the stability of arc welding process can be quantitatively presented. Testing results showed that the accuracy rate of the method was more than 90 percent.

  20. Electric drives

    CERN Document Server

    Boldea, Ion

    2005-01-01

    ENERGY CONVERSION IN ELECTRIC DRIVESElectric Drives: A DefinitionApplication Range of Electric DrivesEnergy Savings Pay Off RapidlyGlobal Energy Savings Through PEC DrivesMotor/Mechanical Load MatchMotion/Time Profile MatchLoad Dynamics and StabilityMultiquadrant OperationPerformance IndexesProblemsELECTRIC MOTORS FOR DRIVESElectric Drives: A Typical ConfigurationElectric Motors for DrivesDC Brush MotorsConventional AC MotorsPower Electronic Converter Dependent MotorsEnergy Conversion in Electric Motors/GeneratorsPOWER ELECTRONIC CONVERTERS (PECs) FOR DRIVESPower Electronic Switches (PESs)The

  1. Characterizing the thermal effects of High Energy Arc Faults

    Energy Technology Data Exchange (ETDEWEB)

    Putorti, Anthony; Bareham, Scott; Praydis, Joseph Jr. [National Institute of Standards and Technology (NIST), Gaithersburg, MD (United States); Melly, Nicholas B. [U.S. Nuclear Regulatory Commission (NRC), Washington, DC (United States)

    2015-12-15

    International and domestic operating experience involving High Energy Arc Faults (HEAF) in Nuclear Power Plant (NPP) electrical power systems have demonstrated the potential to cause extensive damage to electrical components and distribution systems along with damage to adjacent equipment and cables. An international study by the Committee on the Safety of Nuclear Installations (CSNI) gOECD Fire Project. Topical Report No. 1: Analysis of High Energy Arcing Fault (HEAF) Fire Events h published June 25, 2013 [1], illustrates that HEAF events have the potential to be major risk contributors with significant safety consequences and substantial economic loss. In an effort to better understand and characterize the threats posed by HEAF related phenomena, an international project has been chartered; the Joint Analysis of Arc Faults (Joan of ARC) OECD International Testing Program for High Energy Arc Faults. One of the major challenges of this research is how to properly measure and characterize the risk and influence of these events. Methods are being developed to characterize relevant parameters such as; temperature, heat flux, and heat release rate of fires resulting from HEAF events. Full scale experiments are being performed at low (≤ 1000 V) and medium (≤ 35 kV) voltages in electrical components. This paper introduces the methods being developed to measure thermal effects and discusses preliminary results of full scale HEAF experiments.

  2. Underwater plasma arc cutting

    International Nuclear Information System (INIS)

    Leautier, R.; Pilot, G.

    1991-01-01

    This report describes the work done to develop underwater plasma arc cutting techniques, to characterise aerosols from cutting operations on radioactive and non-radioactive work-pieces, and to develop suitable ventilation and filtration techniques. The work has been carried out in the framework of a contract between CEA-CEN Cadarache and the Commission of European Communities. Furthermore, this work has been carried out in close cooperation with CEA-CEN Saclay mainly for secondary emissions and radioactive analysis. The contract started in May 1986 and was completed in December 1988 by a supplementary agreement. This report has been compiled from several progress reports submitted during the work period, contains the main findings of the work and encloses the results of comparative tests on plasma arc cutting

  3. Spatiotemporally resolved characteristics of a gliding arc discharge in a turbulent air flow at atmospheric pressure

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas

    2017-01-01

    A gliding arc discharge was generated in a turbulent air flow at atmospheric pressure driven by a 35 kHz alternating current (AC) electric power. The spatiotemporally resolved characteristics of the gliding arc discharge, including glow-type discharges, spark-type discharges, short-cutting events...

  4. THE ARC TRAIL

    African Journals Online (AJOL)

    canal to fonn part of Moss. • The trail should be made use of by schools and the public. • The area should be cleared of exotic vegetation. e Indigenous trees should be planted to replace the removed exotic trees. The establishment of the ARC trail in 1985 came about as a direct result of the 1983 team1s rec ommenda ti ons ...

  5. Stabilized γ-BIMNVOX solid electrolyte: Ethylene glycol–citrate sol–gel synthesis, microwave-assisted calcination, and structural and electrical characterization

    Energy Technology Data Exchange (ETDEWEB)

    Al-Areqi, Niyazi A.S., E-mail: niyazi.alareqi@gmail.com [Department of Chemistry, Faculty of Applied Science, Taiz University, Taiz, Republic of Yemen (Yemen); Beg, Saba [Department of Chemistry, Aligarh Muslim University, Aligarh 202002 (India); Al-Alas, Ahlam [Department of Chemistry, Faculty of Applied Science, Taiz University, Taiz, Republic of Yemen (Yemen); Hafeez, Shehla [Department of Chemistry, Aligarh Muslim University, Aligarh 202002 (India)

    2013-12-25

    Highlights: •γ-BIMNVOX was synthesized by ethylene glycol–citrate sol–gel route. •γ-BIMNVOX crystallizes by 25-min microwave-assisted calcination. •Smaller particle sizes for microwave calcined BIMNVOX samples. •Best oxide-ion performance for microwave calcined BIMNVOX samples. -- Abstract: Samples of γ-BIMNVOX (Bi{sub 2}V{sub 1−x}Mn{sub x}O{sub 5.5−x/2}; 0.13 ⩽ x ⩽ 0.20) system were synthesized by an ethylene glycol–citrate sol–gel route. The resulting xerogels were then calcined by the microwave heating using a modified domestic microwave oven operated at 2.45 GHz. Microwave-assisted calcination samples in comparison with other conventionally calcined samples were characterized in terms of phase crystallization, stabilization and particle size using simultaneous thermogravimetric–differential thermal analysis (TG–DTA), X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM). The AC impedance spectroscopy was employed for electrical characterization. It was found that the microwave-assisted calcination route successfully produces better crystalline stabilized γ-BIMNVOX samples with appreciably small average particle sizes after only 25 min of microwave heating. The electrical properties of microwave calcined γ-BIMNVOX system make it an advanced low-temperature solid electrolyte suitable for use in oxide-ion based electrochemical applications.

  6. Effect of electric fields on the stabilization of premixed laminar bunsen flames at low AC frequency: Bi-ionic wind effect

    KAUST Repository

    Kim, Minkuk

    2012-03-01

    The stabilization characteristics of laminar premixed bunsen flames have been investigated experimentally by applying AC electric fields at low frequency below 60. Hz together with DC in the single electrode configuration. The blowoff velocity has been measured for varying AC voltage and frequency. A transition frequency between low and high frequency regimes has been identified near 40-50. Hz, where AC electric fields have minimal effect on flame stabilization. In the low frequency regime, the blowoff velocity decreased linearly with AC voltage such that the flames became less stable. This was consistent with the DC result, implying the influence of the ionic wind effect. The variation of blowoff velocity with AC frequency showed a non-monotonic behavior in that the velocity decreased and then increased, exhibiting minimum blowoff velocity near 6-8. Hz. Based on the molecular kinetic theory, the developing degree of ionic wind was derived. By considering the ionic wind effects arising from both positive and negative ions in a flame zone, the bi-ionic wind effect successfully explained the non-monotonic behavior of blowoff velocity with AC frequency in the low frequency regime. © 2011 The Combustion Institute.

  7. Circular arc structures

    KAUST Repository

    Bo, Pengbo

    2011-07-01

    The most important guiding principle in computational methods for freeform architecture is the balance between cost efficiency on the one hand, and adherence to the design intent on the other. Key issues are the simplicity of supporting and connecting elements as well as repetition of costly parts. This paper proposes so-called circular arc structures as a means to faithfully realize freeform designs without giving up smooth appearance. In contrast to non-smooth meshes with straight edges where geometric complexity is concentrated in the nodes, we stay with smooth surfaces and rather distribute complexity in a uniform way by allowing edges in the shape of circular arcs. We are able to achieve the simplest possible shape of nodes without interfering with known panel optimization algorithms. We study remarkable special cases of circular arc structures which possess simple supporting elements or repetitive edges, we present the first global approximation method for principal patches, and we show an extension to volumetric structures for truly threedimensional designs. © 2011 ACM.

  8. How to stimulate the South African rooftop PV market without putting electricity distributors' financial stability at risk

    CSIR Research Space (South Africa)

    Bischof-Niemz, Thomas

    2015-01-01

    Full Text Available to an uncontrollable “under the radar” market for embedded PV, with potentially unsafe practices. Furthermore, it would lead to bankruptcy of many electricity distributors due to lost margins owed to self-consumed PV energy. It is better to embrace the development...

  9. Grid Frequency Support by Single-Phase Electric Vehicles: Fast Primary Control Enhanced by a Stabilizer Algorithm

    DEFF Research Database (Denmark)

    Zecchino, Antonio; Rezkalla, Michel M.N.; Marinelli, Mattia

    2016-01-01

    ancillary services for supporting the power grid. This paper presents modeling and analysis of the benefits of primary frequency regulation by electric vehicles in a microgrid. An innovative control logic algorithm is introduced, with the purpose of curtailing the number of current set-point variations...

  10. Linear Mathematical Model for Seam Tracking with an Arc Sensor in P-GMAW Processes.

    Science.gov (United States)

    Liu, Wenji; Li, Liangyu; Hong, Ying; Yue, Jianfeng

    2017-03-14

    Arc sensors have been used in seam tracking and widely studied since the 80s and commercial arc sensing products for T and V shaped grooves have been developed. However, it is difficult to use these arc sensors in narrow gap welding because the arc stability and sensing accuracy are not satisfactory. Pulse gas melting arc welding (P-GMAW) has been successfully applied in narrow gap welding and all position welding processes, so it is worthwhile to research P-GMAW arc sensing technology. In this paper, we derived a linear mathematical P-GMAW model for arc sensing, and the assumptions for the model are verified through experiments and finite element methods. Finally, the linear characteristics of the mathematical model were investigated. In torch height changing experiments, uphill experiments, and groove angle changing experiments the P-GMAW arc signals all satisfied the linear rules. In addition, the faster the welding speed, the higher the arc signal sensitivities; the smaller the groove angle, the greater the arc sensitivities. The arc signal variation rate needs to be modified according to the welding power, groove angles, and weaving or rotate speed.

  11. PNNL 331 Building Arc Flash Team Investigation Report

    Energy Technology Data Exchange (ETDEWEB)

    Deichman, Mark L.; Drewrey, John C.; Hodges, Hurtis; Madson, Vernon J.; Minton, Allen L.; Montgomery, Daniel M.; Olson, Marvin E.; Rojas, Pedro H.; Sanan, Sanjay K.; Sharp, Reed D.; Sparks, Bobby R.; Swearingen, Gary L.

    2006-06-06

    On Friday, April 21, 2006, a PNNL electrician was performing repair of an electrical system for the 331 Building chilled water pump (CHWP) No.2, when an electrical arc flash occurred inside a 480V combination motor starter. The electrician was taken to the on-site medical provider for evaluation and was released for return to work without restriction. The electrician was not shocked, but did receive a minor, superficial (first degree) burn on the left wrist. This report, the result of a thorough review by the 331 Building Arc Flash Assessment Team, provides an in-depth look at the steps leading up to the arc-flash and recommendations and opportunities for improvement.

  12. The stability of the circadian rhythm of green finches (Carduelis chloris) under the influence of a weak electrical field.

    Science.gov (United States)

    Lintzen, T; Boese, G; Müller, M; Eichmeier, J; Ruhenstroth-Bauer, G

    1989-01-01

    Free-running activity rhythms of nine green finches (Carduelis chloris) were studied under the influence of a 10-Hz square-wave electrical field. With a field strength of magnitude of E = 2.5 V/m in the empty cage, the population had a mean period of 23.64 +/- 0.77 hr. In the same experiment, but without the electrical field, the period was 23.66 +/- 0.80 hr. These results are in contradiction to Wever's description of a field-induced shortening of the period. A series of experiments with 10-Hz pulses of the same square-wave form, yet with various field strengths (8.7 and 65.2 V/m), also gave no effects.

  13. Radiation of transient high-current arcs: energy measurements in the optical range

    International Nuclear Information System (INIS)

    Bauchire, J M; Hong, D; Rabat, H; Riquel, G

    2012-01-01

    When no protection is used, the radiation emitted by a high-power electric arc can be dangerous for the eyes and the skin of a person. To ensure effective protection, it is first necessary to know the energy emitted by such arcs. The aim of our work was to experimentally determine the energy emitted by high-current (from 4 to 40 kA) transient arcs, for two different (10 cm and 2 m) lengths and for electrodes in copper or steel. These experiments enabled the radiative energy of the arcs to be quantified and also showed the influence of metal vapors in the spectral distribution of the radiation.

  14. Electrical conductivity and chemical stability of BaCe0· 8− xAxGd0 ...

    Indian Academy of Sciences (India)

    -1 in air at 1073 K. BaCe0.7In0.1Gd0.2O3− and BaCe0.7Zr0.1Gd0.2O3− ceramics exhibit an excellent chemical stability against boiling water. Indium is a suitable doping element to promote the sintering densification and to enhance both ...

  15. Unipolar arcing phenomena observed in laboratory and nature

    Energy Technology Data Exchange (ETDEWEB)

    Sanduloviciu, M. [Al. I. Cuza Univ. (Romania)

    1995-12-31

    Unipolar arcing phenomena observed as coherent {open_quotes}plasma{close_quotes} balls operating on a surface of constant potential are explained in the frame of a new already proposed self-organisation mechanism considered at the origin of the formation and stability of extended coherent structures observed in plasma devices.

  16. The ARCS radial collimator

    Directory of Open Access Journals (Sweden)

    Stone M.B.

    2015-01-01

    Full Text Available We have designed, installed, and commissioned a scattered beam radial collimator for use at the ARCS Wide Angular Range Chopper Spectrometer at the Spallation Neutron Source. The collimator has been designed to work effectively for thermal and epithermal neutrons and with a range of sample environments. Other design considerations include the accommodation of working within a high vacuum environment and having the ability to quickly install and remove the collimator from the scattered beam. We present here characterization of the collimator's performance and methodologies for its effective use.

  17. APPARATUS FOR ARC WELDING

    Science.gov (United States)

    Lingafelter, J.W.

    1960-04-01

    An apparatus is described in which a welding arc created between an annular electrode and a workpiece moves under the influence of an electromagnetic field about the electrode in a closed or annular path. This mode of welding is specially suited to the enclosing of nuclear-fuel slugs in a protective casing. For example, a uranium slug is placed in an aluminum can, and an aluminum closure is welded to the open end of the can along a closed or annular path conforming to the periphery of the end closure.

  18. Gas tungsten arc welder

    International Nuclear Information System (INIS)

    Christiansen, D.W.; Brown, W.F.

    1984-01-01

    A welder for automated closure of fuel pins by a gas tungsten arc process in which a rotating length of cladding is positioned adjacent a welding electrode in a sealed enclosure. An independently movable grinder, co-axial with the electrode, is provided in the enclosure for refurbishing the used electrode between welds. The specification also discloses means for loading of the cladding with fuel pellets and for placement of reflectors, gas capsules and end caps. Gravity feed conveyor and inerting means are also described. (author)

  19. Electric Arc Furnace as a Source of Emission of Polychlorinated Dibenzo-p-Dioxins and Polychlorinated Dibenzofurans in Perspective of the Council Directive 96/61 EC Concerning Integrated Pollution Prevention and Control

    Directory of Open Access Journals (Sweden)

    Sofilić, T.

    2008-01-01

    daily care for environmental protection and preservation. This Directive integrates control of emissions and overall impact of industrial installations on the environment, meaning recognition of the entire impact from particular industrial processes on the environment (air, water, soil, waste, noise, use of raw materials, energy efficiency, prevention of accidents, etc.. The IPPC Directive has introduced a system of authorization (environmental permit that needs to be obtained in order to perform business activities and run processes using the best available techniques (BAT.Taking into account the harmful impact of PCDDs/Fs on the environment, and their unavoidability in metallurgical processes, a series of methods has been developed for their partial prevention or at least reduction of their concentration in smoke gas discharge, and thus prevent environmental pollution through these very harmful compounds. In order to prevent the occurrence of PCDDs/Fs metallurgical processes often use methods based on the principle of selective catalyst reduction. For removal of the already generated PCDDs/Fs from waste gases methods of thermal decomposition at high temperatures or various sorption, i. e. "dry" and "wet" cleaning techniques are used.As the implementation of the IPPC Directive is a complex procedure requiring highly educated experts, significant investments into production processes and their modernization, or sometimeseven replacement, steel shops need to timely prepare themselves for the obligations in order to harmonize the existing regulation with the requirements of the IPPC Directive.The requirements of the Directive have to be studied thoroughly. The required steps have to be carefully thought through, previously identifying the cost and time frame necessary to bring the existing electric arc furnace (EAF steel production processes into conformance with the requirements of the IPPC Directive.The paper discusses the requirements of the IPPC Directive that are

  20. Thin surface layers of SiO2 obtained from tetraethoxysilane (TEOS) in electric discharges stabilized by a dielectric barrier

    International Nuclear Information System (INIS)

    Schmidt-Szalowski, K.; Fabianowski, W.; Rzanek-Boroch, Z.; Gutkowski, R.

    1998-01-01

    The reported research was devoted to the process of thin layer deposition in a discharge at atmospheric pressure stabilized by a dielectric barrier. Thin surface layers composed mainly of silicon dioxide were produced by polycondensation of tetraethoxysilane vapor in mixtures with helium gas with a small amount of oxygen. The influence was studied of the voltage applied and of the time elapsed in the deposition process, on the thickness of the layer, as were the changes of composition of the deposited layers during and after storage. It is shown that good passivating pinhole-free silicon oxide layers can be produced in surface barrier discharges. (J.U.)

  1. A Michelson interferometer system for testing the stability of a piezo-electric actuator intended for use in space

    International Nuclear Information System (INIS)

    Aplin, K L; Middleton, K F

    2007-01-01

    The Laser Interferometer Space Antenna (LISA) experiment will search for gravitational waves generated by cataclysmic events far back in astronomical history. LISA is an interferometer formed by three spacecraft positioned five million km apart, and to observe gravitational waves, it must monitor test mass positions with picometre level resolution. One of the numerous technological challenges is to identify an actuator with appropriate accuracy, precision and stability for positioning of the optical fibres used to deliver LISA's laser sources. We have developed a Michelson interferometer system to determine the temporal and thermal stability of candidate actuators, with an emphasis on characterisation in the milliHertz frequency range required for gravitational wave detection in space. This paper describes the interferometer data logging and calibration and presents preliminary results in the form of a 'noise spectrum' generated from the small perturbation of a nominally static mirror. The maximum displacement of the mirror was ∼50 nm with sub-Hz noise levels of 0.1-1 nm√Hz. This is within the LISA noise specification, and confirms that the apparatus is stable enough for the characterisation of the actuator

  2. Electrical isolation, thermal stability and rf loss in a multilayer GaAs planar doped barrier diode structure bombarded by H+ and Fe+ ions

    Science.gov (United States)

    Vo, V. T.; Koon, K. L.; Hu, Z. R.; Dharmasiri, C. N.; Subramaniam, S. C.; Rezazadeh, A. A.

    2004-04-01

    Electrical isolation in multilayer GaAs planar doped barrier (PDB) diode structures produced by H+ and Fe+ ion implantation were investigated. For an H+ bombardment with a dose of 1×1015cm-2, a sheet resistivity as high as 3×108 Ω/sq and thermal stability up to 400 °C has been achieved. For samples bombarded by Fe+ ions, a similar high sheet resistivity has also been achieved although a longer annealing time (15 min) and a higher annealing temperature (550 °C) were needed. The rf dissipation losses of coplanar waveguide (CPW) "thru" lines fabricated on bombarded multilayer PDBD structure samples were also examined. The measured rf losses were 1.65 dB/cm at 10 GHz and 3 dB/cm at 40 GHz, similar to the values that a CPW line exhibits on a semi-isolating GaAs substrate.

  3. Electrical reliability, multilevel data storage and mechanical stability of MoS2-PMMA nanocomposite-based non-volatile memory device

    International Nuclear Information System (INIS)

    Bhattacharjee, Snigdha; Sarkar, Pranab Kumar; Roy, Asim; Prajapat, Manoj

    2017-01-01

    Molybdenum disulfide (MoS 2 ) is of great interest for its applicability in various optoelectronic devices. Here we report the resistive switching properties of polymethylmethacrylate embedding MoS 2 nano-crystals. The devices are developed on an ITO-coated PET substrate with copper as the top electrode. Systematic evaluation of resistive switching parameters, on the basis of MoS 2 content, suggests non-volatile memory characteristics. A decent ON/OFF ratio, high retention time and long endurance of 3  ×  10 3 , 10 5 s and 10 5 cycles are respectively recorded in a device with 1 weight percent (wt%) of MoS 2 . The bending cyclic measurements confirm the flexibility of the memory devices with good electrical reliability as well as mechanical stability. In addition, multilevel storage has been demonstrated by controlling the current compliance and span of voltage sweeping in the memory device. (paper)

  4. Dual-gated volumetric modulated arc therapy

    International Nuclear Information System (INIS)

    Fahimian, Benjamin; Wu, Junqing; Wu, Huanmei; Geneser, Sarah; Xing, Lei

    2014-01-01

    Gated Volumetric Modulated Arc Therapy (VMAT) is an emerging radiation therapy modality for treatment of tumors affected by respiratory motion. However, gating significantly prolongs the treatment time, as delivery is only activated during a single respiratory phase. To enhance the efficiency of gated VMAT delivery, a novel dual-gated VMAT (DG-VMAT) technique, in which delivery is executed at both exhale and inhale phases in a given arc rotation, is developed and experimentally evaluated. Arc delivery at two phases is realized by sequentially interleaving control points consisting of MUs, MLC sequences, and angles of VMAT plans generated at the exhale and inhale phases. Dual-gated delivery is initiated when a respiration gating signal enters the exhale window; when the exhale delivery concludes, the beam turns off and the gantry rolls back to the starting position for the inhale window. The process is then repeated until both inhale and exhale arcs are fully delivered. DG-VMAT plan delivery accuracy was assessed using a pinpoint chamber and diode array phantom undergoing programmed motion. DG-VMAT delivery was experimentally implemented through custom XML scripting in Varian’s TrueBeam™ STx Developer Mode. Relative to single gated delivery at exhale, the treatment time was improved by 95.5% for a sinusoidal breathing pattern. The pinpoint chamber dose measurement agreed with the calculated dose within 0.7%. For the DG-VMAT delivery, 97.5% of the diode array measurements passed the 3%/3 mm gamma criterion. The feasibility of DG-VMAT delivery scheme has been experimentally demonstrated for the first time. By leveraging the stability and natural pauses that occur at end-inspiration and end-exhalation, DG-VMAT provides a practical method for enhancing gated delivery efficiency by up to a factor of two

  5. Study on wave power generation of electricity using torsion arc blade type horizontal axis wind turbine; Nejire enko yokugata suihei jiku fusha wo mochiita haryoku hatsuden ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Kojima, N.; Kishimura, K. [Meiji University, Tokyo (Japan)

    1996-10-27

    Windmilling characteristics of a combination of a torsion arc blade type (TABT) horizontal axis wind turbine and a reverse torsion arc blade type (RTABT) horizontal axis wind turbine were evaluated in a wave activated power generation experiment. The TABT wind turbine had six blades, and the front and rear parts of the blade were twisted in the same direction, which caused the direction of rotor rotation to change as the direction of wind along the shaft changed. The RTABT wind turbine had twelve blades, and the front and rear parts of the blade were twisted reverse to each other, which allowed the direction of rotor rotation to stay constant even in the presence of wind direction reversal. To keep the direction of rotor rotation unchanged in the presence of flow direction reversal along the power generating turbine shaft, a single-stage type RTABT wind turbine and a double-stage type were used, the double-stage type being a series connection of a first-stage RTABT (for blowout and suction) and second-stage TABT (for blowout only). Both single-type and double-type rotated in the same direction irrespective of the direction of air flow. The output of the double type was obtained by adding up the values obtained from the individual turbines. The double type was two to three times higher in efficiency than the single type in turbine revolution and power output. 2 refs., 13 figs.

  6. Effect of the weld thermal cycles by the modified indirect electric arc (MIEA) on the mechanical properties of the AA6061-T6 alloy; Efecto de los ciclo termicos de soldadura por arco electrico indirecto modificado (AEIM) en las propiedades mecanicas de la aleacion AA6061-T6

    Energy Technology Data Exchange (ETDEWEB)

    Ambriz, R. A.; Barrera, G.; Garcia, R.; Lopez, V. H.

    2009-07-01

    Results of temperature measurements during welding of 12.7 mm thick AA6061-T6 alloy plates by modified indirect electric arc (MIEA) are presented. This study describes the thermal cycles of the heat affected zone (HAZ) and also in the fusion zone. Depending upon the position of the transducers, the maximum temperatures measured in the HAZ range from 308 to 693 degree centigrade, these measurements were related with the tensile test results, and the failure zone reported previously by the authors. It was observed that, there is a decrease in the mechanical strength of the welded joints, due to the microstructural changes suffered by AA6061-T6 alloy in which formation of the {beta}occurs according to the TTT transformation diagram. The inherent cooling conditions of the weld pool observed for the MIEA technique (only one pass of welding), have permitted to establish the characteristics of solidification and microstructure for a specific cooling rate. (Author) 24 refs.

  7. In vitro biocompatibility and electrical stability of thick-film platinum/gold alloy electrodes printed on alumina

    Science.gov (United States)

    Carnicer-Lombarte, Alejandro; Lancashire, Henry T.; Vanhoestenberghe, Anne

    2017-06-01

    Objective. High-density electrode arrays are a powerful tool in both clinical neuroscience and basic research. However, current manufacturing techniques require the use of specialised techniques and equipment, which are available to few labs. We have developed a high-density electrode array with customisable design, manufactured using simple printing techniques and with commercially available materials. Approach. Electrode arrays were manufactured by thick-film printing a platinum-gold alloy (Pt/Au) and an insulating dielectric on 96% alumina ceramic plates. Arrays were conditioned in serum and serum-free conditions, with and without 1 kHz, 200 µA, charge balanced stimulation for up to 21 d. Array biocompatibility was assessed using an extract assay and a PC-12 cell contact assay. Electrode impedance, charge storage capacity and charge injection capacity were before and after array conditioning. Main results. The manufactured Pt/Au electrodes have a highly porous surface and exhibit electrical properties comparable to arrays manufactured using alternative techniques. Materials used in array manufacture were found to be non-toxic to L929 fibroblasts by extract assay, and neuronal-like PC-12 cells adhered and extended neurites on the array surfaces. Arrays remained functional after long-term delivery of electrical pulses while exposed to protein-rich environments. Charge storage capacities and charge injection capacities increased following stimulation accounted for by an increase in surface index (real surface area) observed by vertical scanning interferometry. Further, we observed accumulation of proteins at the electrode sites following conditioning in the presence of serum. Significance. This study demonstrates the in vitro biocompatibility of commercially available thick-film printing materials. The printing technique is both simple and versatile, with layouts readily modified to produce customized electrode arrays. Thick-film electrode arrays are an

  8. Resistivity of flame plasma in an electric field

    International Nuclear Information System (INIS)

    Ikuta, Kazunari.

    1989-01-01

    A generalized Ohm's law is obtained for a flame plasma in an electric field for the study of arc resistivity in an electromagnetic launcher (EML). The effective resistivity of flame plasma is reduced by the source, which suggests the injection of premixed combustible fuel into the arc plasma in EML in order to reduce the electron energy of the arc. The reduction of electron energy in the arc is desirable to minimize the damage of electrodes in EML. (author)

  9. Laser Assisted Plasma Arc Welding

    Energy Technology Data Exchange (ETDEWEB)

    FUERSCHBACH,PHILLIP W.

    1999-10-05

    Experiments have been performed using a coaxial end-effecter to combine a focused laser beam and a plasma arc. The device employs a hollow tungsten electrode, a focusing lens, and conventional plasma arc torch nozzles to co-locate the focused beam and arc on the workpiece. Plasma arc nozzles were selected to protect the electrode from laser generated metal vapor. The project goal is to develop an improved fusion welding process that exhibits both absorption robustness and deep penetration for small scale (< 1.5 mm thickness) applications. On aluminum alloys 6061 and 6111, the hybrid process has been shown to eliminate hot cracking in the fusion zone. Fusion zone dimensions for both stainless steel and aluminum were found to be wider than characteristic laser welds, and deeper than characteristic plasma arc welds.

  10. Calorimeter probes for measuring high thermal flux. [in arc jets

    Science.gov (United States)

    Russell, L. D.

    1979-01-01

    Expendable, slug-type calorimeter probes were developed for measuring high heat-flux levels of 10-30 kW/sq cm in electric-arc jet facilities. The probes were constructed with thin tungsten caps mounted on Teflon bodies. The temperature of the back surface of the tungsten cap is measured, and its time rate of change gives the steady-state absorbed heat flux as the calorimeter probe heats to destruction when inserted into the arc jet. Design, construction, test, and performance data are presented.

  11. DC graphite arc furnace, a simple system to reduce mixed waste volume

    Energy Technology Data Exchange (ETDEWEB)

    Wittle, J.K.; Hamilton, R.A.; Trescot, J. [and others

    1995-12-31

    The volume of low-level radioactive waste can be reduced by the high temperature in a DC Graphite Arc Furnace. This volume reduction can take place with the additional benefit of having the solid residue being stabilized by the vitrified product produced in the process. A DC Graphite Arc Furnace is a simple system in which electricity is used to generate heat to vitrify the material and thermally decompose any organic matter in the waste stream. Examples of this type of waste are protective clothing, resins, and grit blast materials produced in the nuclear industry. The various Department of Energy (DOE) complexes produce similar low-level waste streams. Electro-Pyrolysis, Inc. and Svedala/Kennedy Van Saun are engineering and building small 50-kg batch and up to 3,000 kg/hr continuous feed DC furnaces for the remediation, pollution prevention, and decontamination and decommissioning segments of the treatment community. This process has been demonstrated under DOE sponsorship at several facilities and has been shown to produce stable waste forms from surrogate waste materials.

  12. Temperature and electric field stabilities of dielectric and insulating properties for c-axis-oriented CaBi4Ti4O15 films

    Science.gov (United States)

    Kimura, Junichi; Takuwa, Itaru; Matsushima, Masaaki; Yasui, Shintaro; Yamada, Tomoaki; Funakubo, Hiroshi

    2013-07-01

    Temperature and electric field dependencies of the dielectric and insulating properties of (001)-oriented epitaxial CaBi4Ti4O15 films grown on (100)cSrRuO3//(100)SrTiO3 substrates were investigated and compared with those of conventional (100)-oriented epitaxial (Ba0.3Sr0.7)TiO3 and SrTiO3 films. All films showed negative temperature dependency of the capacitance from 25 to 500 °C, and their changes were -18%, -83%, and -58% for CaBi4Ti4O15, (Ba0.3Sr0.7)TiO3, and SrTiO3 films, respectively. Smaller change of the capacitance against dc electric field was also observed for CaBi4Ti4O15 films. Moreover, the maximum leakage current density of CaBi4Ti4O15 films measured at ±100 kV/cm was below 10-3 A/cm2 up to 500 °C, which was smaller than those of (Ba0.3Sr0.7)TiO3 and SrTiO3 films. These results indicate that (001)-oriented CaBi4Ti4O15 films are a useful candidate as the capacitor material applicable for the high temperature use because of its high stability against temperature and an electric field as well as the good insulating characteristics.

  13. The AHA Moment: Assessment of the Redox Stability of Ionic Liquids Based on Aromatic Heterocyclic Anions (AHAs) for Nuclear Separations and Electric Energy Storage.

    Science.gov (United States)

    Shkrob, Ilya A; Marin, Timothy W

    2015-11-19

    Because of their extended conjugated bond network, aromatic compounds generally have higher redox stability than less saturated compounds. We conjectured that ionic liquids (ILs) consisting of aromatic heterocyclic anions (AHAs) may exhibit improved radiation and electrochemical stability. Such properties are important in applications of these ILs as diluents in radionuclide separations and electrolytes in the electric energy storage devices. In this study, we systematically examine the redox chemistry of the AHAs. Three classes of these anions have been studied: (i) simple 5-atom ring AHAs, such as the pyrazolide and triazolides, (ii) AHAs containing an adjacent benzene ring, and (iii) AHAs containing electron-withdrawing groups that were introduced to reduce their basicity and interaction with metal ions. It is shown that fragmentation in the reduced and oxidized states of these AHAs does not generally occur, and the two main products, respectively, are the H atom adduct and the imidyl radical. The latter species occurs either as an N σ-radical or as an N π-radical, depending on the length of the N-N bond, and the state that is stabilized in the solid matrix is frequently different from that having the lowest energy in the gas phase. In some instances, the formation of the sandwich π-stack dimer radical anions has been observed. For trifluoromethylated anions, H adduct formation did not occur; instead, there was facile loss of fluoride from their fluorinated groups. The latter can be problematic in nuclear separations, but beneficial in batteries. Overall, our study suggests that AHA-based ILs are viable candidates for use as radiation-exposed diluents and electrolytes.

  14. 3D stability analysis of Rayleigh–Bénard convection of a liquid metal layer in the presence of a magnetic field—effect of wall electrical conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Dimopoulos, Dimitrios; Pelekasis, Nikos A, E-mail: pel@uth.gr [Department of Mechanical and Industrial Engineering, University of Thessaly, Pedion Areos, Volos 38334 (Greece)

    2014-10-01

    Rayleigh–Bénard stability of a liquid metal layer of rectangular cross section is examined in the presence of a strong magnetic field that is aligned with the horizontal direction of the cross section. The latter is much longer than the vertical direction and the cross section assumes a large aspect ratio. The side walls are treated as highly conducting. Linear stability analysis is performed allowing for three-dimensional instabilities that develop along the longitudinal direction. The finite element methodology is employed for the discretization of the stability analysis formulation while accounting for the electrical conductivity of the cavity walls. The Arnoldi method provides the dominant eigenvalues and eigenvectors of the problem. In order to facilitate parallel implementation of the numerical solution at large Hartmann numbers, Ha, domain decomposition is employed along the horizontal direction of the cross section. As the Hartmann number increases a real eigenvalue emerges as the dominant unstable eigenmode, signifying the onset of thermal convection, whose major vorticity component in the core of the layer is aligned with the direction of the magnetic field. Its wavelength along the longitudinal direction of the layer is on the order of twice its height and increases as Ha increases. The critical Grashof was obtained for large Ha and it was seen to scale like Ha {sup 2} signifying the balance between buoyancy and Lorentz forces. For well conducting side walls, the nature of the emerging flow pattern is determined by the combined conductivity of Hartmann walls and Hartmann layers, c{sub H}  + Ha {sup −1}. When poor conducting Hartmann walls are considered, c{sub H} ≪ 1, the critical eigensolution is characterized by well defined Hartmann and side layers. The side layers are characterized by fast fluid motion in the magnetic field direction as a result of the electromagnetic pumping in the vicinity of the Hartmann walls. Increasing the electrical

  15. Effect of conductivity changes on the stability of electric signal waveforms in dwarf stonebashers (Mormyridae; Pollimyrus castelnaui, P. marianne).

    Science.gov (United States)

    Baier, Bernd

    2008-10-01

    The dwarf stonebasher sibling species Pollimyrus castelnaui and P. marianne use differences in the electric organ discharges (EODs) for species recognition. As EOD waveforms are affected by water conductivity changes, the reliability of species recognition might be impeded due to natural variability in the environment. EODs of P. castelnaui (N = 8) and P. marianne (N = 8) under high (250 microS/cm) and low (25 microS/cm) conductivity were recorded and compared. Local peaks of the EODs of both species were significantly and predictably modified due to the conductivity change but species-specific differences were always recognizable. The duration of the EODs was not influenced by the conductivity change. Temperature alterations modified the duration in a linear relationship, allowing the determination of Q(10) values (1.6 for P. castelnaui's and 1.7 for P. marianne's EODs). As the species-specific differences are not masked by conductivity effects, EOD discrimination seems to be a reliable species recognition mechanism under natural circumstances.

  16. Arc Interference Behavior during Twin Wire Gas Metal Arc Welding Process

    Directory of Open Access Journals (Sweden)

    Dingjian Ye

    2013-01-01

    Full Text Available In order to study arc interference behavior during twin wire gas metal arc welding process, the synchronous acquisition system has been established to acquire instantaneous information of arc profile including dynamic arc length variation as well as relative voltage and current signals. The results show that after trailing arc (T-arc is added to the middle arc (M-arc in a stable welding process, the current of M arc remains unchanged while the agitation increases; the voltage of M arc has an obvious increase; the shape of M arc changes, with increasing width, length, and area; the transfer frequency of M arc droplet increases and the droplet itself becomes smaller. The wire extension length of twin arc turns out to be shorter than that of single arc welding.

  17. Light and Electrically Induced Phase Segregation and Its Impact on the Stability of Quadruple Cation High Bandgap Perovskite Solar Cells.

    Science.gov (United States)

    Duong, The; Mulmudi, Hemant Kumar; Wu, YiLiang; Fu, Xiao; Shen, Heping; Peng, Jun; Wu, Nandi; Nguyen, Hieu T; Macdonald, Daniel; Lockrey, Mark; White, Thomas P; Weber, Klaus; Catchpole, Kylie

    2017-08-16

    Perovskite material with a bandgap of 1.7-1.8 eV is highly desirable for the top cell in a tandem configuration with a lower bandgap bottom cell, such as a silicon cell. This can be achieved by alloying iodide and bromide anions, but light-induced phase-segregation phenomena are often observed in perovskite films of this kind, with implications for solar cell efficiency. Here, we investigate light-induced phase segregation inside quadruple-cation perovskite material in a complete cell structure and find that the magnitude of this phenomenon is dependent on the operating condition of the solar cell. Under short-circuit and even maximum power point conditions, phase segregation is found to be negligible compared to the magnitude of segregation under open-circuit conditions. In accordance with the finding, perovskite cells based on quadruple-cation perovskite with 1.73 eV bandgap retain 94% of the original efficiency after 12 h operation at the maximum power point, while the cell only retains 82% of the original efficiency after 12 h operation at the open-circuit condition. This result highlights the need to have standard methods including light/dark and bias condition for testing the stability of perovskite solar cells. Additionally, phase segregation is observed when the cell was forward biased at 1.2 V in the dark, which indicates that photoexcitation is not required to induce phase segregation.

  18. Cliff stability assessment using electrical resistivity tomography at the historic WWII D-Day invasion site, Pointe du Hoc, France

    Science.gov (United States)

    Everett, M. E.; Udphuay, S.; Warden, R.

    2007-05-01

    The 1944 D-Day invasion site at Pointe du Hoc, Normandy, France is an important WWII battlefield and cultural resource but is at risk from chalk cliff collapse. The American Battle Monuments Commission tasked us to evaluate the geohazard to the observation post and other cliff-side buildings of historical significance. Geophysical multi-electrode resistivity profiling is used to study cliff stability and the condition of the observation- post foundations. Preliminary 2-D geological interpretations are provided of individual profiles. The copious steel, concrete and void spaces at the site renders hydrogeological interpretation challenging but tractable. The cliff face appears to be relatively intact and well-drained. Several routes taken by groundwater into fractures within the chalk were identified mainly on the western side of the site. The eastern side is drier and somewhat sheltered from the Atlantic storms but may contain large void spaces that could efficiently transmit groundwater flow during heavy precipitation events, thereby imperiling the major antiaircraft gun emplacement occupied by Col. Rudder in the early days of the Allied invasion. The forward German observation post perched close to the sea stack, which now hosts the U.S. Ranger memorial, may be moving with the soil and not securely anchored to bedrock. A complex failure mechanism is identified as a combination of groundwater dissolution of the fractured chalk and sea wave attack at the cliff base.

  19. Optimizing of Work Arc Furnace to Decopperisation of Flash Slag

    Directory of Open Access Journals (Sweden)

    Bydałek A.W.

    2015-09-01

    Full Text Available Discusses an attempt to optimize the operation of an electric furnace slag to be decopperisation suspension of the internal recycling process for the production of copper. The paper presents a new method to recover copper from metallurgical slags in arc-resistance electric furnace. It involves the use of alternating current for a first period reduction, constant or pulsed DC in the final stage of processing. Even distribution of the electric field density in the final phase of melting caused to achieve an extremely low content of metallic copper in the slag phase. They achieved by including the economic effects by reducing the time reduction.

  20. Detection of arc fault based on frequency constrained independent component analysis

    Science.gov (United States)

    Yang, Kai; Zhang, Rencheng; Xu, Renhao; Chen, Yongzhi; Yang, Jianhong; Chen, Shouhong

    2015-02-01

    Arc fault is one of the main reasons of electrical fires. As a result of weakness, randomness and cross talk of arc faults, very few of methods have been successfully used to protect loads from all arc faults in low-voltage circuits. Therefore, a novel detection method is developed for detection of arc faults. The method is based on frequency constrained independent component analysis. In the process of the method derivation, a band-pass filter was introduced as a constraint condition to separate independent components of mixed signals. In the process of the independent component separations, although the fault mixed signals were under the conditions of the strong background noise and the frequency aliasing, the effective high frequency components of arc faults could be separated by frequency constrained independent component analysis. Based on the separated components, the power spectrums of them were calculated to classify the normal and the arc fault conditions. The validity of the developed method was verified by using an arc fault experimental platform set up. The results show that arc faults of nine typical electrical loads are successfully detected based on frequency constrained independent component analysis.

  1. Swarm Observation of Field-Aligned Currents Associated With Multiple Auroral Arc Systems

    Science.gov (United States)

    Wu, J.; Knudsen, D. J.; Gillies, D. M.; Donovan, E. F.; Burchill, J. K.

    2017-10-01

    Auroral arcs occur in regions of upward field-aligned currents (FACs); however, the relation is not one to one, since kinetic energy of the current-carrying electrons is also important in the production of auroral luminosity. Multiple auroral arc systems provide an opportunity to study the relation between FACs and auroral brightness in detail. In this study, we have identified two types of FAC configurations in multiple parallel arc systems using ground-based optical data from the Time History of Events and Macroscale Interactions during Substorms all-sky imagers, magnetometers and electric field instruments on board the Swarm satellites. In "unipolar FAC" events, each arc is an intensification within a broad, unipolar current sheet and downward return currents occur outside of this broad sheet. In "multipolar FAC" events, multiple arc systems represent a collection of multiple up/down current pairs. By collecting 17 events with unipolar FAC and 12 events with multipolar FACs, we find that (1) unipolar FAC events occur most frequently between 20 and 21 magnetic local time and multipolar FAC events tend to occur around local midnight and within 1 h after substorm onset. (2) Arcs in unipolar FAC systems have a typical width of 10-20 km and a spacing of 25-50 km. Arcs in multipolar FAC systems are wider and more separated. (3) Upward currents with more arcs embedded have larger intensities and widths. (4) Electric fields are strong and highly structured on the edges of multiple arc system with unipolar FAC. The fact that arcs with unipolar FAC are much more highly structured than the associated currents suggests that arc multiplicity is indicative not of a structured generator deep in the magnetosphere, but rather of the magnetosphere-ionosphere coupling process.

  2. Design of arc power supply for neutral beam injection system based on super capacitor energy storage

    International Nuclear Information System (INIS)

    Yang Puqiong; Xuan Weimin; Cao Jianyong; Li Qing; Liu Xiaolong

    2015-01-01

    The arc power supply is one of the most important equipment for neutral beam injection system. The stability of arc discharge and the quality of ion beam extraction were determined by its performance. For improving stability of the arc discharge, reducing the power network capacity and decreasing impulse on power network, the topology of the arc power supply applied the structure of DC/DC converter based on technology of super capacitor energy storage and switching power supply. Several IGBT power modules are operated in parallel, and it can improve the arc power supply's operating frequency and dynamic response. A filter circuit and a current fast transferring circuit were designed based on a detailed analysis on working process of the arc power sup- ply. According to the requirements and parameters of the arc power supply, and the current response of RL first order circuit, the minimum filter inductances were accurately calculated. Finally, using the model and Matlab, the performance of the arc power supply was simulated and verified, and it meets the design requirement. (authors)

  3. Monitor For Electrical-Discharge Machining

    Science.gov (United States)

    Burley, Richard K.

    1993-01-01

    Circuit monitors electrical-discharge-machining (EDM) process to detect and prevent abnormal arcing, which can produce unacceptable "burn" marks on workpiece. When voltage between EDM electrode and workpiece behaves in manner indicative of abnormal arcing, relay made to switch off EDM power, which remains off until operator attends to EDM setup and resets monitor.

  4. Electrode voltage fall and total voltage of a transient arc

    Science.gov (United States)

    Valensi, F.; Ratovoson, L.; Razafinimanana, M.; Masquère, M.; Freton, P.; Gleizes, A.

    2016-06-01

    This paper deals with an experimental study of the components of a transient arc total voltage with duration of a few tens of ms and a current peak close to 1000 A. The cathode tip is made of graphite whereas the flat anode is made either of copper or of graphite; the electrodes gap is a few mm. The analysis of the electrical parameters is supported and validated by fast imaging and by two models: the first one is a 2D physical model of the arc allowing to calculate both the plasma temperature field and the arc voltage; the second model is able to estimate the transient heating of the graphite electrode. The main aim of the study was to detect the possible change of the cathode voltage fall (CVF) during the first instants of the arc. Indeed it is expected that during the first ms the graphite cathode is rather cool and the main mechanism of the electron emission should be the field effect emission, whereas after several tens of ms the cathode is strongly heated and thermionic emission should be predominant. We have observed some change in the apparent CVF but we have shown that this apparent change can be attributed to the variation of the solid cathode resistance. On the other hand, the possible change of CVF corresponding to the transition between a ‘cold’ and a ‘hot’ cathode should be weak and could not be characterized considering our measurement uncertainty of about 2 V. The arc column voltage (ACV) was estimated by subtracting the electrode voltage fall from the total arc voltage. The experimental transient evolution of the ACV is in very good agreement with the theoretical variation predicted by the model, showing the good ability of the model to study this kind of transient arc.

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

    Science.gov (United States)

    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.

  6. [Arc spectrum diagnostic and heat coupling mechanism analysis of double wire pulsed MIG welding].

    Science.gov (United States)

    Liu, Yong-qiang; Li, Huan; Yang, Li-jun; Zheng, Kai; Gao, Ying

    2015-01-01

    A double wire pulsed MIG welding test system was built in the present paper, in order to analyze the heat-coupling mechanism of double wire pulsed MIG welding, and study are temperature field. Spectroscopic technique was used in diagnostic analysis of the are, plasma radiation was collected by using hollow probe method to obtain the arc plasma optical signal The electron temperature of double wire pulsed MIG welding arc plasma was calculated by using Boltzmann diagram method, the electron temperature distribution was obtained, a comprehensive analysis of the arc was conducted combined with the high speed camera technology and acquisition means of electricity signal. The innovation of this paper is the combination of high-speed camera image information of are and optical signal of arc plasma to analyze the coupling mechanism for dual arc, and a more intuitive analysis for are temperature field was conducted. The test results showed that a push-pull output was achieved and droplet transfer mode was a drop in a pulse in the welding process; Two arcs attracted each other under the action of a magnetic field, and shifted to the center of the arc in welding process, so a new heat center was formed at the geometric center of the double arc, and flowing up phenomenon occurred on the arc; Dual arc electronic temperature showed an inverted V-shaped distribution overall, and at the geometric center of the double arc, the arc electron temperature at 3 mm off the workpiece surface was the highest, which was 16,887.66 K, about 4,900 K higher than the lowest temperature 11,963.63 K.

  7. Hybrid laser arc welding: State-of-art review

    Science.gov (United States)

    Acherjee, Bappa

    2018-02-01

    Hybrid laser arc welding simultaneously utilizes the arc welding and the laser welding, in a common interaction zone. The synergic effects of laser beam and eclectic arc in the same weld pool results in an increase of welding speed and penetration depth along with the enhancement of gap bridging capability and process stability. This paper presents the current status of this hybrid technique in terms of research, developments and applications. Effort is made to present a comprehensive technical know-how about this process through a systematic review of research articles, industrial catalogues, technical notes, etc. In the introductory part of the review, an overview of the hybrid laser arc welding is presented, including operation principle, process requirements, historical developments, benefits and drawbacks of the process. This is followed by a detailed discussion on control parameters those govern the performance of hybrid laser arc welding process. Thereafter, a report of improvements of performance and weld qualities achieved by using hybrid welding process is presented based on review of several research papers. The succeeding sections furnish the examples of industrial applications and the concluding remarks.

  8. Structure and thermal stability of arc evaporated (Ti{sub 0.33}Al{sub 0.67}){sub 1-x}Si{sub x}N thin films

    Energy Technology Data Exchange (ETDEWEB)

    Flink, A. [Department of Physics, Chemistry, and Biology (IFM) Linkoeping University, SE-581 83 Linkoeping (Sweden)], E-mail: axefl@ifm.liu.se; Andersson, J.M. [Seco Tools AB, SE-737 82 Fagersta (Sweden); Alling, B. [Department of Physics, Chemistry, and Biology (IFM) Linkoeping University, SE-581 83 Linkoeping (Sweden); Institute of Physics of Complex Matter, Swiss Federal Institute of Technology, Lausanne (EPFL) 1015 Lausanne (Switzerland); Daniel, R. [Christian Doppler Laboratory for Advanced Hard Coatings, Department of Physical Metallurgy, University of Leoben, A-8700 Leoben (Austria); Sjoelen, J.; Karlsson, L. [Seco Tools AB, SE-737 82 Fagersta (Sweden); Hultman, L. [Department of Physics, Chemistry, and Biology (IFM) Linkoeping University, SE-581 83 Linkoeping (Sweden)

    2008-11-28

    (Ti{sub 0.33}Al{sub 0.67}){sub 1-x}Si{sub x}N (0 {<=} x {<=} 0.29) thin solid films were deposited onto cemented carbide substrates by arc evaporation and analyzed using analytical electron microscopy, X-ray diffraction, nanoindentation, and density functional theory. As-deposited films with x {<=} 0.02 consisted mainly of a metastable c-(Ti,Al)N solid solution for which Si serves as a veritable grain refiner. Additional Si promoted growth of a hexagonal wurtzite (Al,Ti,Si)N solid solution, which dominated at 0.02 < x < 0.17. For x {>=} 0.17, the films were X-ray amorphous. Despite these widely different microstructures, all as-deposited films had nanoindentation hardness in the narrow range of 22-25 GPa. Isothermal annealing of the x = 0.01 alloy film at a temperature of 900 deg. C , corresponding to that in turning operation, resulted in spinodal decomposition into c-AlN and TiN and precipitation of h-AlN. For x = 0.09 films, annealing between 600 deg. C and 1000 deg. C yielded c-TiN precipitation from the h-(Al,Ti,Si)N phase. Furthermore, the x = 0.01 and x = 0.09 films exhibited substantial age hardening at 900 deg. C , to 34 GPa and 29 GPa due to spinodal decomposition and c-TiN precipitation, respectively. Films with a majority of c-(Ti,Al)N phase worked best in steel turning tests, while films with x > 0.02 developed cracks during such operation. We propose that the cracks are due to tensile strain which is caused by a decrease in molar volume during the phase transformation from hexagonal wurtzite (Al,Ti,Si)N into cubic TiN phase, which results in degradation in machining performance.

  9. Numerical and experimental study of heat transfers in an arc plasma. Application to TIG arc welding

    International Nuclear Information System (INIS)

    Borel, Damien

    2013-01-01

    The arc welding is used for many industrial applications, especially GTA welding. Given the excellent quality of the produced welds, GTA welding is used for the majority of the interventions (repairs, joined sealing) on the French nuclear park. This work is part of a project carried out by EDF R and D which aims to simulate the whole process and builds a tool able to predict the welds quality. In this study, we focus on the development of a predictive model of the exchanged heat flux at the arc - work piece interface, responsible of the work piece fusion. The modeling of the arc plasma using the electric module of the hydrodynamics software Code Saturne R developed by EDF R and D is required. Two types of experimental tests are jointly carried out to validate this numerical model: i) on density and temperature measurements of plasma by atomic emission spectroscopy and ii) on the evaluation of the heat transfers on the work piece surface. This work also aims at demonstrate that the usual method of using an equivalent thermal source to model the welding process, can be replaced by our plasma model, without the numerous trials inherent to the usual method. (author)

  10. Percussive arc welding apparatus

    Science.gov (United States)

    Hollar, Jr., Donald L.

    2002-01-01

    A percussive arc welding apparatus includes a generally cylindrical actuator body having front and rear end portions and defining an internal recess. The front end of the body includes an opening. A solenoid assembly is provided in the rear end portion in the internal recess of the body, and an actuator shaft assembly is provided in the front end portion in the internal recess of the actuator body. The actuator shaft assembly includes a generally cylindrical actuator block having first and second end portions, and an actuator shaft having a front end extending through the opening in the actuator body, and the rear end connected to the first end portion of the actuator block. The second end portion of the actuator block is in operational engagement with the solenoid shaft by a non-rigid connection to reduce the adverse rebound effects of the actuator shaft. A generally transversely extending pin is rigidly secured to the rear end of the shaft. One end of the pin is received in a slot in the nose housing sleeve to prevent rotation of the actuator shaft during operation of the apparatus.

  11. [Spectra and thermal analysis of the arc in activating flux plasma arc welding].

    Science.gov (United States)

    Chai, Guo-Ming; Zhu, Yi-Feng

    2010-04-01

    In activating flux plasma arc welding the welding arc was analyzed by spectra analysis technique, and the welding arc temperature field was measured by the infrared sensing and computer image technique. The distribution models of welding arc heat flow density of activating flux PAW welding were developed. The composition of welding arc affected by activated flux was studied, and the welding arc temperature field was studied. The results show that the spectral lines of argon atom and ionized argon atom of primary ionization are the main spectra lines of the conventional plasma welding arc. The spectra lines of weld metal are inappreciable in the spectra lines of the conventional plasma welding arc. The gas particle is the main in the conventional plasma welding arc. The conventional plasma welding arc is gas welding arc. The spectra lines of argon atom and ionized argon atom of primary ionization are intensified in the activating flux plasma welding arc, and the spectra lines of Ti, Cr and Fe elements are found in the activating flux plasma welding arc. The welding arc temperature distribution in activating flux plasma arc welding is compact, the outline of the welding arc temperature field is narrow, the range of the welding arc temperature distribution is concentrated, the welding arc radial temperature gradient is large, and the welding arc radial temperature gradient shows normal Gauss distribution.

  12. Prediction of the cathodic arc root behaviour in a hollow cathode thermal plasma torch

    International Nuclear Information System (INIS)

    Freton, Pierre; Gonzalez, Jean-Jacques; Escalier, Gaelle

    2009-01-01

    The upper part of a well type cathode (WTC) plasma torch is modelled for several conditions in an air medium in the presence of an electric arc. The plasma flow created by the electric arc is described and the results compared with the data from the literature. Special attention is paid to the description of arc root attachment and to its movement due to the balance of forces. A fine description of the magnetic field produced by the external solenoid is reported. The model is based on the Fluent software implemented with specific developments to be adapted to the thermal plasma domain. The paper shows the necessity to provide an accurate description of the external magnetic field due to the strong influence of the radial magnetic field component. Overall, we propose an original approach for arc root movement description which contributes to the understanding of the flow behaviour in the WTC torch.

  13. Amanteigamento por aspersão térmica na soldagem em operação de dutos de pequena espessura: estabilidade e penetração do arco voltaico Buttering by thermal spraying in welding in-service repair of pipes with small thickness: arc stability and penetration

    Directory of Open Access Journals (Sweden)

    Nilceu Novicki

    2011-09-01

    thermal spraying. The characteristics of buttering layers deposited by two thermal spraying processes (arc and conventional flame were compared, in special the influence of their degree of oxidation in dependence of the carrying gas (pressurized air or argonium on the arc stability and penetration of weld beads SMAW over plain carbon steels previously buttered with similar composition layers. The results allowed to correlate the stability of the arc to the level of oxidation of the sprayed layers. (Temperature measurements on the surface of the sprayed layers showed that, since the process of thermal spray occur in an non-stopped way until the final thickness of the coating, the superficial temperature is increased with the thickness of the deposit, what results in a higher content of oxides, which is associated to an arc instability and a greater penetration of the molten pool. X-ray diffractrogams and oxygen analysis proved the influence of this element in the changing profile of the fusion zone. As an alternative to the use of compressed air, its substitution by the inert gas argon as carrying gas was evaluated, verifying very benefic effects - significant reduction of penetration e good arc stability - believed coming from the reduction of oxidation in the sprayed layer by the protective effect of the inert gas. The evaluation of the results permitted to establish criteria of welding with lower risks of burn-through compared to a condition without buttering layers.

  14. Electro-arc plasmatron for high-productive synthesis of diamond coatings

    International Nuclear Information System (INIS)

    Vasil'ev, V.V.; Strel'nitskij, V.E.

    2001-01-01

    The tests of the electro-arc plasma torch with the gas vortex arc stabilization and with the combined fixing of an arc length (gas dynamic and magnetic) were carried out. Usage of an additional magnetic stabilization of an arc length has allowed considerably to minimize the accidental fluctuations of a substrate temperature from ± 10 degree C without a magnet up to ± 2 degree C with a magnet. It was shown that the plasma torch can in two modes: in a mode of abnormal expansion of a plasma jet and in a mode of absence of its expansion. The maximal values of the DC synthesis efficiency and area of a uniform part of a coating were received in a mode of the plasma jet expansion absence with using of the gas dynamic correction of a temperature and the concentration fields of atomic hydrogen near to a substrate

  15. Characteristics of a stable arc based on FAST and MIRACLE observations

    Directory of Open Access Journals (Sweden)

    P. Janhunen

    2000-02-01

    Full Text Available A stable evening sector arc is studied using observations from the FAST satellite at 1250 km altitude and the MIRACLE ground-based network, which contains all-sky cameras, coherent radars (STARE, and magnetometers. Both FAST and STARE observe a northward electric field region of about 200 km width and a field magnitude of about 50 mV/m southward of the arc, which is a typical signature for an evening-sector arc. The field-aligned current determined from FAST electron and magnetometer data are in rather good agreement within the arcs. Outside the arcs, the electron data misses the current carriers of the downward FAC probably because it is mainly carried by electrons of smaller energy than the instrument threshold. Studying the westward propagation speed of small undulations associated with the arc using the all-sky cameras gives a velocity of about 2 km/s. This speed is higher than the background ionospheric plasma speed (about 1 km/s, but it agrees rather well with the idea originally proposed by Davis that the undulations reflect an E × B motion in the acceleration region. The ground magnetograms indicate that the main current flows slightly south of the arc. Computing the ionospheric conductivity from FAST electron data and using the ground magnetograms to estimate the current yields an ionospheric electric field pattern, in rather good agreement with FAST results.Key words: Ionosphere (auroral ionosphere; ionosphere-magnetosphere interactions - Magnetospheric physics (auroral phenomena

  16. Surface Characterization of LMMS Molybdenum Disilicide Coated HTP-8 Using Arc- Jet Hypersonic Flow

    Science.gov (United States)

    Stewart, David A.

    2000-01-01

    Surface properties for an advanced Lockheed Martin Missile and Space (LMMS) molybdenum disilicide coated insulation (HTP-8) were determined using arc-jet flow to simulate Earth entry at hypersonic speeds. The catalytic efficiency (atom recombination coefficients) for this advanced thermal protection system was determined from arc-jet data taken in both oxygen and nitrogen streams at temperatures ranging from 1255 K to roughly 1600 K. In addition, optical and chemical stability data were obtained from these test samples.

  17. On the dynamics of cutting arc plasmas: the role of the power supply ripple

    Directory of Open Access Journals (Sweden)

    L. Prevosto

    2012-09-01

    Full Text Available The power sources used in cutting arc torches are usually poorly stabilized and have a large ripple factor. The strong oscillatory components in the voltage and arc current produce in turn, large fluctuations in the plasma quantities. Experimental observations on the dynamics of the non-equilibrium plasma inside the nozzle of a 30 A oxygen cutting torch with a 7 % ripple level of its power source are reported in this work.

  18. Modelling of gas-metal arc welding taking into account metal vapour

    Energy Technology Data Exchange (ETDEWEB)

    Schnick, M; Fuessel, U; Hertel, M; Haessler, M [Institute of Surface and Manufacturing Technology, Technische Universitaet Dresden, D-01062 Dresden (Germany); Spille-Kohoff, A [CFX Berlin Software GmbH, Karl-Marx-Allee 90, 10243 Berlin (Germany); Murphy, A B [CSIRO Materials Science and Engineering, PO Box 218, Lindfield NSW 2070 (Australia)

    2010-11-03

    The most advanced numerical models of gas-metal arc welding (GMAW) neglect vaporization of metal, and assume an argon atmosphere for the arc region, as is also common practice for models of gas-tungsten arc welding (GTAW). These models predict temperatures above 20 000 K and a temperature distribution similar to GTAW arcs. However, spectroscopic temperature measurements in GMAW arcs demonstrate much lower arc temperatures. In contrast to measurements of GTAW arcs, they have shown the presence of a central local minimum of the radial temperature distribution. This paper presents a GMAW model that takes into account metal vapour and that is able to predict the local central minimum in the radial distributions of temperature and electric current density. The influence of different values for the net radiative emission coefficient of iron vapour, which vary by up to a factor of hundred, is examined. It is shown that these net emission coefficients cause differences in the magnitudes, but not in the overall trends, of the radial distribution of temperature and current density. Further, the influence of the metal vaporization rate is investigated. We present evidence that, for higher vaporization rates, the central flow velocity inside the arc is decreased and can even change direction so that it is directed from the workpiece towards the wire, although the outer plasma flow is still directed towards the workpiece. In support of this thesis, we have attempted to reproduce the measurements of Zielinska et al for spray-transfer mode GMAW numerically, and have obtained reasonable agreement.

  19. Production of a large area diffuse arc plasma with multiple cathode

    International Nuclear Information System (INIS)

    Wang Cheng; Cui Hai-Chao; Li Wan-Wan; Liao Meng-Ran; Xia Wei-Dong; Xia Wei-Luo

    2017-01-01

    An arc channel at atmospheric pressure tends to shrink generally. In this paper, a non-transferred DC arc plasma device with multiple cathode is introduced to produce a large area arc plasma at atmospheric pressure. This device is comprised of a 42-mm diameter tubular chamber, multiple cathode which is radially inserted into the chamber, and a tungsten anode with a nozzle in its center. In argon/helium atmosphere, a large area and circumferential homogenous diffuse arc plasma, which fills the entire cross section surrounded by the cathode tips, is observed. Results show that the uniformity and stability of diffuse arc plasma are strongly related to the plasma forming gas. Based on these experimental results, an explanation to the arc diffusion is suggested. Moreover, the electron excitation temperature and electron density measured in diffuse helium plasma are much lower than those of constricted arc column, which indicates the diffuse helium plasma probably deviates from the local thermodynamic equilibrium state. Unlike the common non-transferred arc plasma devices, this device can provide a condition for axial-fed feedstock particles. The plasma device is attempted to spheroidize alumina powders by using the central axis to send the powder. Results show that the powder produced is usually a typical hollow sphere. (paper)

  20. Electromagnetic radiation generated by arcing in low density plasma

    Science.gov (United States)

    Vayner, Boris V.; Ferguson, Dale C.; Snyder, David B.; Doreswamy, C. V.

    1996-01-01

    An unavoidable step in the process of space exploration is to use high-power, very large spacecraft launched into Earth orbit. Obviously, the spacecraft will need powerful energy sources. Previous experience has shown that electrical discharges occur on the surfaces of a high-voltage array, and these discharges (arcs) are undesirable in many respects. Moreover, any high voltage conductor will interact with the surrounding plasma, and that interaction may result in electrical discharges between the conductor and plasma (or between two conductors with different potentials, for example, during docking and extravehicular activity). One very important aspect is the generation of electromagnetic radiation by arcing. To prevent the negative influence of electromagnetic noise on the operation of spacecraft systems, it seems necessary to determine the spectra and absolute levels of the radiation, and to determine limitations on the solar array bias voltage that depend on the parameters of LEO plasma and the technical requirements of the spacecraft equipment. This report describes the results of an experimental study and computer simulation of the electromagnetic radiation generated by arcing on spacecraft surfaces. A large set of high quality data was obtained during the Solar Array Module Plasma Interaction Experiment (SAMPIE, flight STS-62) and ground test. These data include the amplitudes of current, pulse forms, duration of each arc, and spectra of plasma waves. A theoretical explanation of the observed features is presented in this report too. The elaborated model allows us to determine the parameters of the electromagnetic noise for different frequency ranges, distances from the arcing site, and distinct kinds of plasma waves.

  1. Arcing phenomena in fusion devices workshop

    Energy Technology Data Exchange (ETDEWEB)

    Clausing, R.E.

    1979-01-01

    The workshop on arcing phenomena in fusion devices was organized (1) to review the pesent status of our understanding of arcing as it relates to confinement devices, (2) to determine what informaion is needed to suppress arcing and (3) to define both laboratory and in-situ experiments which can ultimately lead to reduction of impurities in the plasma caused by arcing. The workshop was attended by experts in the area of vacuum arc electrode phenomena and ion source technology, materials scientists, and both theoreticians and experimentalists engaged in assessing the importance of unipolar arcing in today's tokamaks. Abstracts for papers presented at the workshop are included.

  2. Arcing phenomena in fusion devices workshop

    International Nuclear Information System (INIS)

    Clausing, R.E.

    1979-01-01

    The workshop on arcing phenomena in fusion devices was organized (1) to review the pesent status of our understanding of arcing as it relates to confinement devices, (2) to determine what informaion is needed to suppress arcing and (3) to define both laboratory and in-situ experiments which can ultimately lead to reduction of impurities in the plasma caused by arcing. The workshop was attended by experts in the area of vacuum arc electrode phenomena and ion source technology, materials scientists, and both theoreticians and experimentalists engaged in assessing the importance of unipolar arcing in today's tokamaks. Abstracts for papers presented at the workshop are included

  3. Opposite effect of mast cell stabilizers ketotifen and tranilast on the vasoconstrictor response to electrical field stimulation in rat mesenteric artery.

    Directory of Open Access Journals (Sweden)

    Esther Sastre

    Full Text Available OBJECTIVES: We analyzed whether mast cell stabilization by either ketotifen or tranilast could alter either sympathetic or nitrergic innervation function in rat mesenteric arteries. METHODS: Electrical field stimulation (EFS-induced contraction was analyzed in mesenteric segments from 6-month-old Wistar rats in three experimental groups: control, 3-hour ketotifen incubated (0.1 αmol/L, and 3-hour tranilast incubated (0.1 mmol/L. To assess the possible participation of nitrergic or sympathetic innervation, EFS contraction was analyzed in the presence of non-selective nitric oxide synthase (NOS inhibitor L-NAME (0.1 mmol/L, α-adrenergic receptor antagonist phentolamine (0.1 µmol/L, or the neurotoxin 6-hydroxydopamine (6-OHDA, 1.46 mmol/L. Nitric oxide (NO and superoxide anion (O2.(- levels were measured, as were vasomotor responses to noradrenaline (NA and to NO donor DEA-NO, in the presence and absence of 0.1 mmol/L tempol. Phosphorylated neuronal NOS (P-nNOS expression was also analyzed. RESULTS: EFS-induced contraction was increased by ketotifen and decreased by tranilast. L-NAME increased the vasoconstrictor response to EFS only in control segments. The vasodilator response to DEA-NO was higher in ketotifen- and tranilast-incubated segments, while tempol increased vasodilator response to DEA-NO only in control segments. Both NO and O2(- release, and P-nNOS expression were diminished by ketotifen and by tranilast treatment. The decrease in EFS-induced contraction produced by phentolamine was lower in tranilast-incubated segments. NA vasomotor response was decreased only by tranilast. The remnant vasoconstriction observed in control and ketotifen-incubated segments was abolished by 6-OHDA. CONCLUSION: While both ketotifen and tranilast diminish nitrergic innervation function, only tranilast diminishes sympathetic innnervation function, thus they alter the vasoconstrictor response to EFS in opposing manners.

  4. Activity-Dependent Arc Expression and Homeostatic Synaptic Plasticity Are Altered in Neurons from a Mouse Model of Angelman Syndrome

    Science.gov (United States)

    Pastuzyn, Elissa D.; Shepherd, Jason D.

    2017-01-01

    Angelman syndrome (AS) is a neurodevelopmental disorder that results from deletions or mutations in chromosome 15, which usually includes the UBE3A gene. Ube3A protein is an E3 ubiquitin ligase that ubiquitinates proteins and targets them for degradation. The immediate-early gene Arc, a master regulator of synaptic plasticity, was identified as a putative substrate of Ube3A, but there have been conflicting reports on whether Arc is a bona fide E3 ligase substrate. Using multiple approaches, we found no evidence for a physical interaction between Arc and Ube3A in vivo. Nonetheless, activity-induced subcellular distribution of Arc is altered in brains from Ube3am−/p+ mice, with abnormal concentration of Arc at synapses. Furthermore, although activation of Arc transcription is normal, the stability of Arc protein is enhanced in dendrites of hippocampal neurons cultured from Ube3am−/p+ mice. Finally, homeostatic synaptic scaling of surface AMPA receptors does not occur in Ube3am−/p+ hippocampal neurons, reminiscent of neurons that lack Arc protein. Although Ube3A does not seem to bind Arc in a canonical E3 ligase-substrate interaction, Arc-dependent synaptic plasticity is still altered in Ube3am−/p+ mice, which may underlie the cognitive deficits observed in AS. PMID:28804447

  5. Activity-Dependent Arc Expression and Homeostatic Synaptic Plasticity Are Altered in Neurons from a Mouse Model of Angelman Syndrome

    Directory of Open Access Journals (Sweden)

    Elissa D. Pastuzyn

    2017-07-01

    Full Text Available Angelman syndrome (AS is a neurodevelopmental disorder that results from deletions or mutations in chromosome 15, which usually includes the UBE3A gene. Ube3A protein is an E3 ubiquitin ligase that ubiquitinates proteins and targets them for degradation. The immediate-early gene Arc, a master regulator of synaptic plasticity, was identified as a putative substrate of Ube3A, but there have been conflicting reports on whether Arc is a bona fide E3 ligase substrate. Using multiple approaches, we found no evidence for a physical interaction between Arc and Ube3A in vivo. Nonetheless, activity-induced subcellular distribution of Arc is altered in brains from Ube3am−/p+ mice, with abnormal concentration of Arc at synapses. Furthermore, although activation of Arc transcription is normal, the stability of Arc protein is enhanced in dendrites of hippocampal neurons cultured from Ube3am−/p+ mice. Finally, homeostatic synaptic scaling of surface AMPA receptors does not occur in Ube3am−/p+ hippocampal neurons, reminiscent of neurons that lack Arc protein. Although Ube3A does not seem to bind Arc in a canonical E3 ligase-substrate interaction, Arc-dependent synaptic plasticity is still altered in Ube3am−/p+ mice, which may underlie the cognitive deficits observed in AS.

  6. E-region echo characteristics governed by auroral arc electrodynamics

    Directory of Open Access Journals (Sweden)

    S. E. Milan

    Full Text Available Observations of a pair of auroral arc features by two imagers, one ground- and one space-based, allows the associated field-aligned current (FAC and electric field structure to be inferred. Simultaneous observations of HF radar echoes provide an insight into the irregularity-generating mechanisms. This is especially interesting for the E-region echoes observed, which form the focus of our analysis, and from which several conclusions can be drawn, summarized as follows. Latitudinal variations in echo characteristics are governed by the FAC and electric field background. Particularly sharp boundaries are found at the edges of auroral arcs. Within regions of auroral luminosity, echoes have Doppler shifts below the ion-acoustic speed and are proportional to the electric field, suggesting scatter from gradient drift waves. Regions of downward FAC are associated with mixed high and low Doppler shift echoes. The high Doppler shift component is greatly in excess of the ion-acoustic speed, but seems to be commensurate with the driving electric field. The low Doppler shift component appears to be much depressed below expectations.

    Key words. Ionosphere (ionospheric irregularities; electric fields and currents

  7. E-region echo characteristics governed by auroral arc electrodynamics

    Directory of Open Access Journals (Sweden)

    S. E. Milan

    2003-07-01

    Full Text Available Observations of a pair of auroral arc features by two imagers, one ground- and one space-based, allows the associated field-aligned current (FAC and electric field structure to be inferred. Simultaneous observations of HF radar echoes provide an insight into the irregularity-generating mechanisms. This is especially interesting for the E-region echoes observed, which form the focus of our analysis, and from which several conclusions can be drawn, summarized as follows. Latitudinal variations in echo characteristics are governed by the FAC and electric field background. Particularly sharp boundaries are found at the edges of auroral arcs. Within regions of auroral luminosity, echoes have Doppler shifts below the ion-acoustic speed and are proportional to the electric field, suggesting scatter from gradient drift waves. Regions of downward FAC are associated with mixed high and low Doppler shift echoes. The high Doppler shift component is greatly in excess of the ion-acoustic speed, but seems to be commensurate with the driving electric field. The low Doppler shift component appears to be much depressed below expectations.Key words. Ionosphere (ionospheric irregularities; electric fields and currents

  8. Dry hyperbaric gas metal arc welding of subsea pipelines: experiments and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Azar, Amin S.

    2012-07-01

    Ambitions in exploration of oil and gas fields at deeper water depth require continuous investigation and maintenance. The transportation pipelines laid in deep waters are both subjected to corrosion and buckling due to environmental phenomena. They may also often undergo branching (namely hot tapping) to redirect (or add to) the transportation paths. Mechanical joints and welding are both considered as available alternatives when sectioning and replacement of the pipes at shallow waters is necessary, yet, welding is more promising for deep waters where remote operation is central. Fusion welding on the other hand comprises several technological detractions for sound operations under high ambient pressures disregarding its low cost and flexibility. The foremost detracting phenomenon in the arc welding is called 'arc root constriction', which is defined as arc geometry shrinkage under the increased pressure. Consequently, the power delivery to the weld pool at different pressure levels is a major worry. Effects of ionization and dissociation energies of different gases and mixtures, partial pressure of environmental gases including hydrogen and oxygen, gasification and degasification of the weld metal, inclusions that affect the phase transformation, absorption and desorption kinetics, oxidation and deoxidation reactions and many more are the phenomena that can possibly be altered by the gas type and ambient pressure level. Spattering and fume generation is a problematic issue since the arc is rather unstable under high pressure. Thus, seeking the effect of different chamber gas mixtures on welding parameters, final microstructure and mechanical properties is the main objective of this work.Statistical analysis of the collected voltage and current waveforms is carried out to identify the source of arc misbehavior and instability (discussed in Paper I). The stochastic parameters is related to the electrical stability and resolved into a number of varying

  9. Pulmón del soldador de arco Arc welder's lung

    Directory of Open Access Journals (Sweden)

    Luciana Molinari

    2010-12-01

    Full Text Available La siderosis del soldador o neumoconiosis siderótica fue descripta por Doig y McLaughlin en 1936 como una enfermedad pulmonar causada por la inhalación crónica de polvo de hierro en soldadores de arco eléctrico. Presentamos un caso de siderosis del soldador asociada a aumento de los niveles de ferritina, sin hallazgo de depósito de hierro en otros órganos y sin causas evidentes de hemosiderosis secundaria.Pneumoconiosis of electric arc welder or siderotic pneumoconiosis was described by Doig and McLaughlin in 1936 as a lung disease caused by chronic inhalation of iron fumes in electric arc welders. We present a case report of electric arc welder siderosis associated with high levels of ferritin, without findings of iron deposit in any other organ.

  10. Methodology for evaluation of the stability of electric systems of offshore oil platforms in interconnected operations; Metodologia para a avaliacao dos sistemas eletricos das plataformas de petroleo offshore em operacao interligada

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Dalmo Junior; Mendes, Pedro Paulo de Carvalho [Universidade Federal de Itajuba (UNIFEI), MG (Brazil)

    2004-07-01

    The electric system of the platforms usually operates in an isolated way, requesting therefore a redundancy in the generating units so that a can have a reliable and uninterrupted system of their loads. A way to improve the quality in operation in terms of safety, reliability and economy can be the connection of the platforms of petroleum that are close, since it is viable. The objective of this work is to show the methodology for the stability study of the electric system in interlinked operation in way to detail the data of the equipment that are necessary, as: One line Diagram; Transmission lines; Transformers; Power system compensator; Generating; Speed regulators; Voltage regulators; Turbines and other. Another focus of the work is to show some control models and regulation of the electric system to maintain it stable and to show models for the interconnection of two or more platforms. (author)

  11. Hybrid laser-arc welding

    DEFF Research Database (Denmark)

    building and the automotive industry. With its distinguished editor and international team of contributors, Hybrid laser-arc welding, will be a valuable source of reference for all those using this important welding technology. Professor Flemming Ove Olsen works in the Department of Manufacturing...

  12. Hooded arc ion-source

    CERN Multimedia

    CERN PhotoLab

    1972-01-01

    The positioning system for the hooded arc ion-source, shown prior to mounting, consists of four excentric shafts to locate the ion-source and central electrodes. It will be placed on the axis of the SC and introduced into the vacuum tank via the air locks visible in the foreground.

  13. Vacuum Gas Tungsten Arc Welding

    Science.gov (United States)

    Weeks, J. L.; Todd, D. T.; Wooten, J. R.

    1997-01-01

    A two-year program investigated vacuum gas tungsten arc welding (VGTAW) as a method to modify or improve the weldability of normally difficult-to-weld materials. After a vacuum chamber and GTAW power supply were modified, several difficult-to-weld materials were studied and key parameters developed. Finally, Incoloy 903 weld overlays were produced without microfissures.

  14. Magnification Bias in Gravitational Arc Statistics

    Energy Technology Data Exchange (ETDEWEB)

    Caminha, G. B. [Rio de Janeiro, CBPF; Estrada, J. [Fermilab; Makler, M. [Rio de Janeiro, CBPF

    2013-08-29

    The statistics of gravitational arcs in galaxy clusters is a powerful probe of cluster structure and may provide complementary cosmological constraints. Despite recent progresses, discrepancies still remain among modelling and observations of arc abundance, specially regarding the redshift distribution of strong lensing clusters. Besides, fast "semi-analytic" methods still have to incorporate the success obtained with simulations. In this paper we discuss the contribution of the magnification in gravitational arc statistics. Although lensing conserves surface brightness, the magnification increases the signal-to-noise ratio of the arcs, enhancing their detectability. We present an approach to include this and other observational effects in semi-analytic calculations for arc statistics. The cross section for arc formation ({\\sigma}) is computed through a semi-analytic method based on the ratio of the eigenvalues of the magnification tensor. Using this approach we obtained the scaling of {\\sigma} with respect to the magnification, and other parameters, allowing for a fast computation of the cross section. We apply this method to evaluate the expected number of arcs per cluster using an elliptical Navarro--Frenk--White matter distribution. Our results show that the magnification has a strong effect on the arc abundance, enhancing the fraction of arcs, moving the peak of the arc fraction to higher redshifts, and softening its decrease at high redshifts. We argue that the effect of magnification should be included in arc statistics modelling and that it could help to reconcile arcs statistics predictions with the observational data.

  15. STRUVE arc and EUPOS® stations

    Science.gov (United States)

    Lasmane, Ieva; Kaminskis, Janis; Balodis, Janis; Haritonova, Diana

    2013-04-01

    The Struve Geodetic Arc was developed in Years 1816 to 1855, 200 years ago. Historic information on the points of the Struve Geodetic Arc are included in the UNESCO World Heritage list in 2005. Nevertheless, the sites of many points are still not identified nor included in the data bases nowadays. Originally STRUVE arc consisted of 258 main triangles with 265 triangulation points. Currently 34 of the original station points are identified and included in the in the UNESCO World Heritage list. identified original measurement points of the Meridian Arc are located in Sweden (7 points), Norway (15), Finland (83), Russia (1), Estonia (22), Latvia (16), Lithuania (18), Belorussia (28), Ukraine (59) and Moldova (27). In Year 2002 was initiated another large coverage project - European Position Determination System "EUPOS®". Currently there are about 400 continuously operating GNSS (Global Navigation Satellite Systems) stations covering EU countries Estonia, Latvia, Lithuania, Poland, Czech Republic, Slovakia, Hungary, Bulgaria, Romania and East European countries Ukraine and Moldavia. EUPOS® network is a ground based GNSS augmentation system widely used for geodesy, land surveying, geophysics and navigation. It gives the opportunity for fast and accurate position determination never available before. It is an honorable task to use the EUPOS® system for research of the Struve triangulation former sites. Projects with Struve arc can popularize geodesy, geo-information and its meaning in nowadays GIS and GNSS systems. Struve Arc and its points is unique cooperation cross-border object which deserve special attention because of their natural beauty and historical value for mankind. GNSS in geodesy discovers a powerful tool for the verification and validation of the height values of geodetic leveling benchmarks established historically almost 200 years ago. The differential GNSS and RTK methods appear very useful to identify vertical displacement of landscape by means of

  16. Powerful demolition techniques - plasma fusion cutting, contact arc metal cutting (CAMC), and contact arc metal grinding (CAMG)

    International Nuclear Information System (INIS)

    Bach, F.W.; Kremer, G.; Ruemenapp, T.

    2006-01-01

    One of the most complicated steps in the demolition of nuclear power plants is the disassembly of radiologically burdened large components. Most of this work must be performed remotely and under a cover of water. Moreover, dimensions, structures, and locations pose problems. Various techniques of disassembly are available which have specific pros and cons. Thermal cutting techniques, i.e. plasma fusion cutting, contact arc metal cutting (CAMC), and contact arc metal grinding (CAMG), can be used with comparatively simple handling systems even for large material thicknesses and complex geometries. These thermal cutting techniques have been advanced considerably at the Institute for Materials Technology of the University of Hanover in recent years. In plasma fusion cutting, the workpiece is molten, partly evaporated, and the melt is blown out of the kerf by the gas jet. CAMC and CAMG are based on the thermal abrasion of electrically conducting materials under water by means of repeated non-steady short-circuit high-current arcs resulting from contacts between the electrode and the workpiece. Unlike plasma or laser beam cutting, hollow structures and sandwich structures pose no problems. The performance capability of plasma fusion cutting and contact arc metal cutting has been demonstrated impressively in the disassembly of reactor internals of the Karlsruhe multi-purpose research reactor (MZFR). (orig.)

  17. Influence of arc current and pressure on non-chemical equilibrium air arc behavior

    Science.gov (United States)

    Yi, WU; Yufei, CUI; Jiawei, DUAN; Hao, SUN; Chunlin, WANG; Chunping, NIU

    2018-01-01

    The influence of arc current and pressure on the non-chemical equilibrium (non-CE) air arc behavior of a nozzle structure was investigated based on the self-consistent non-chemical equilibrium model. The arc behavior during both the arc burning and arc decay phases were discussed at different currents and different pressures. We also devised the concept of a non-equilibrium parameter for a better understanding of non-CE effects. During the arc burning phase, the increasing current leads to a decrease of the non-equilibrium parameter of the particles in the arc core, while the increasing pressure leads to an increase of the non-equilibrium parameter of the particles in the arc core. During the arc decay phase, the non-CE effect will decrease by increasing the arc burning current and the nozzle pressure. Three factors together—convection, diffusion and chemical reactions—influence non-CE behavior.

  18. Production of hyperthermal hydrogen atoms by an arc discharge

    International Nuclear Information System (INIS)

    Samano, E.C.

    1993-01-01

    A magnetically confined thermal electric arc gas heater has been designed and built as a suitable source of heat for dissociating hydrogen molecules with energy in the range of a few eV. Specifically, the average beam kinetic energy is determined to be 1.5 eV, the dissociation rate is 0.5 atoms per molecule and the atom beam intensity in the forward direction is 1018 atoms/sr-sec. The working pressure in the arc discharge region is from 15 to 25 torr. This novel atom source has been successfully ignited and operated with pure hydrogen during several hours of continuous performance, maintaining its characteristics. The hyperthermal hydrogen atom beam, which is obtained from this source is analyzed and characterized in a high vacuum system, the characterization of the atom beam is accomplished by two different methods: calorimetry and surface ionization. Calorimetic sensor were used for detecting the atom beam by measuring the delivered power of the impinging atoms on the sensor surface. In the second approach an H-surface production backscattering experiment from a low work function surface was conducted. The validity of these two methods is discussed, and the results are compared. The different collision mechanisms to dissociate and ionize hydrogen molecules in the arch discharge are reviewed, as well as the physics of electric arcs. Finally, a Monte Carlo simulation program is used to calculate the ionization probability of low energy atoms perpendicularly reflected from a surface converter, as a model for atom surface ionization

  19. Impact of revascularization of coronary chronic total occlusion on left ventricular function and electrical stability: analysis by speckle tracking echocardiography and signal-averaged electrocardiogram.

    Science.gov (United States)

    Sotomi, Yohei; Okamura, Atsunori; Iwakura, Katsuomi; Date, Motoo; Nagai, Hiroyuki; Yamasaki, Tomohiro; Koyama, Yasushi; Inoue, Koichi; Sakata, Yasushi; Fujii, Kenshi

    2017-06-01

    The present study aimed to assess the mechanisms of effects of percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) from two different aspects: left ventricular (LV) systolic function assessed by two-dimensional speckle tracking echocardiography (2D-STE) and electrical stability evaluated by late potential on signal-averaged electrocardiogram (SAECG). We conducted a prospective observational study with consecutive CTO-PCI patients. 2D-STE and SAECG were performed before PCI, and after 1-day and 3-months of procedure. 2D-STE computed global longitudinal strain (GLS) and regional longitudinal strain (RLS) in CTO area, collateral blood-supplying donor artery area, and non-CTO/non-donor area. A total of 37 patients (66 ± 11 years, 78% male) were analyzed. RLS in CTO and donor areas and GLS were significantly improved 1-day after the procedure, but these improvements diminished during 3 months. The improvement of RLS in donor area remained significant after 3-months the index procedure (pre-PCI -13.4 ± 4.8% vs. post-3M -15.1 ± 4.5%, P = 0.034). RLS in non-CTO/non-donor area and LV ejection fraction were not influenced. Mitral annulus velocity was improved at 3-month follow-up (5.0 ± 1.4 vs. 5.6 ± 1.7 cm/s, P = 0.049). Before the procedure, 12 patients (35%) had a late potential. All components of the late potential (filtered QRS duration, root-mean-square voltage in the terminal 40 ms, and duration of the low amplitude signal <40 μV) were not improved. CTO-PCI improved RLS in the donor area at 3-month follow-up without changes of LV ejection fraction. Although higher prevalence of late potential in the current population compared to healthy population was observed, late potential as a surrogate of arrhythmogenic substrate was not influenced by CTO-PCI.

  20. Notes on the ExactPack Implementation of the DSD Explosive Arc Solver

    Energy Technology Data Exchange (ETDEWEB)

    Kaul, Ann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Doebling, Scott William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-12

    It has been shown above that the discretization scheme implemented in the ExactPack solver for the DSD Explosive Arc equation is consistent with the Explosive Arc PDE. In addition, a stability analysis has provided a CFL condition for a stable time step. Together, consistency and stability imply convergence of the scheme, which is expected to be close to first-order in time and second-order in space. It is understood that the nonlinearity of the underlying PDE will affect this rate somewhat.

  1. Review of Arc Models in Distribution Networks

    Directory of Open Access Journals (Sweden)

    Yin Qi

    2016-01-01

    Full Text Available The incipient fault in underground cable is recognized as arc fault. Then the arc model selection is very important for the incipient fault detection. The arc features and some typical models have been introduced in detail, including traditional thermal based models, arc models in low voltage and models of arc in long free air. At last, the Kizilcay’s model is recommended to analyze the incipient fault in underground cable for its accuracy and widely utilized. Finally, some conclusions are summarized.

  2. Inline screw feeding vacuum arc thruster

    Science.gov (United States)

    Kronhaus, Igal; Laterza, Matteo; Maor, Yonatan

    2017-04-01

    A new type of micropropulsion device for nanosatellite applications is presented—the inline-screw-feeding vacuum-arc thruster (ISF-VAT). This thruster couples a conventional "triggerless" ignition geometry with a feeding mechanism that maintains a steady state discharge performance. The feeding mechanism implements a screw action on a central cathode rod. At a predetermined rate, a complete and uniform erosion of the cathodes tip is obtained as well as "healing" of the insulator coating. The inline feeding of the cathode forces the arc to emerge on the tip of the cathode, flush with the exit plane of the anode. This enables the plasma plume to efficiently accelerate away from the thruster, eliminating the need for an additional ion acceleration stage. The ISF-VAT feeding mechanism is computer controlled and offers reliable operation of the thruster over a large number of pulses. Characterization of the ISF-VAT performance is presented, conducted on an experimental prototype in the Aerospace Plasma Laboratory, Technion. Measurement results of the mass flow rate, electrical parameters of the discharge, and thrust are presented. Using a Ti cathode at a discharge power of 3 W, a mass flow rate of ≈1.8 ×10-9 kg/s and a thrust level ≈ 7 μN were measured. More than 106 pulses were demonstrated in a single run, accumulating a total impulse of 0.2 Ns. The thruster prototype dimensions are 15 × 15 × 65 mm3 and are ≈ 60 g in mass.

  3. The redox state of arc mantle using Zn/Fe systematics.

    Science.gov (United States)

    Lee, Cin-Ty A; Luffi, Peter; Le Roux, Véronique; Dasgupta, Rajdeep; Albaréde, Francis; Leeman, William P

    2010-12-02

    Many arc lavas are more oxidized than mid-ocean-ridge basalts and subduction introduces oxidized components into the mantle. As a consequence, the sub-arc mantle wedge is widely believed to be oxidized. The Fe oxidation state of sub-arc mantle is, however, difficult to determine directly, and debate persists as to whether this oxidation is intrinsic to the mantle source. Here we show that Zn/Fe(T) (where Fe(T) = Fe(2+) + Fe(3+)) is redox-sensitive and retains a memory of the valence state of Fe in primary arc basalts and their mantle sources. During melting of mantle peridotite, Fe(2+) and Zn behave similarly, but because Fe(3+) is more incompatible than Fe(2+), melts generated in oxidized environments have low Zn/Fe(T). Primitive arc magmas have identical Zn/Fe(T) to mid-ocean-ridge basalts, suggesting that primary mantle melts in arcs and ridges have similar Fe oxidation states. The constancy of Zn/Fe(T) during early differentiation involving olivine requires that Fe(3+)/Fe(T) remains low in the magma. Only after progressive fractionation does Fe(3+)/Fe(T) increase and stabilize magnetite as a fractionating phase. These results suggest that subduction of oxidized crustal material may not significantly alter the redox state of the mantle wedge. Thus, the higher oxidation states of arc lavas must be in part a consequence of shallow-level differentiation processes, though such processes remain poorly understood.

  4. Plasma's sweeping arc

    International Nuclear Information System (INIS)

    Pichon, Max

    2010-01-01

    Full text: It is purely elemental, returning materials to their basic atoms through extreme heat and then recondensing them in useful ways. Plasma arc gasification is the latest advanced waste treatment (AWT)concept to hit our shores, courtesy of Zenergy Australia. According to its fans, plasma technology can eliminate all domestic waste to landfill and turn it into beneficial by-products. Japan has toyed with it for a decade, but the idea is now creating a bit of buzz, in the US in particular. Consultancy URS last year undertook a review of 16 advanced technologies for the City of Los Angeles and determined plasma arc gasification was one of the most promising. The Waste Management Association of Australia (VVMAA), however, is cautious - too many AWT projects here have failed to live up to their promises. Plasma arc gasification works on the same principle as a welding machine. An inert gas is passed through an electrical arc between two electrodes and becomes ionised (called plasma), reaching temperatures as high as 13,900°C. It is then injected into the plasma converter holding the waste. Zenergy is working with US technology company Plasma Waste Recycling (PWR), which says it can convert 80 per cent of waste to syngas, a mixture of carbon monoxide and hydrogen that can be used to generate renewable electricity. The inorganic compounds in the waste come out as a solid, either molten metal to be cast as scrap steel or a slag that can be used as a building material aggregate or spun into mineral wool. “The plasma arc process is the next generation for AWT plants as there is no incineration involved, no fly ash, no bottom ash and nothing left to landfill,” said Zenergy Australia's Paul Prasad. He estimates a plant could convert up to 175,000 tonnes of household waste a year into energy or reusable by-products. Technically, it also gets around Australia's fears over incineration, though whether that is really the case in practice remains to be seen

  5. Arc-discharge system for nondestructive detection of flaws in thin ceramic coatings

    International Nuclear Information System (INIS)

    Scott, G.W.; Davis, E.V.

    1978-04-01

    The feasibility of nondestructively detecting small cracks or holes in plasma-sprayed ceramic coatings with an electric arc-discharge system was studied. We inspected ZrO 2 coatings 0.46 mm (0.018 in.) thick on Incoloy alloy 800 substrates. Cracks were artificially induced in controlled areas of the specimens by straining the substrates in tension. We designed and built a system to scan the specimen's surface at approximately 50 μm (0.002 in.) clearance with a sharp-pointed metal-tipped probe at high dc potential. The system measures the arc currents occurring at flaws, or plots a map of the scanned area showing points where the arc current exceeds a preset threshold. A theoretical model of the probe-specimen circuit shows constant dc potential to be the best choice for arc-discharge inspection of insulating coatings. Experimental observations and analysis of the data disclosed some potential for flaw description

  6. The SOAR Gravitational Arc Survey

    Science.gov (United States)

    Makler, M.; Furlanetto, C.; Santiago, B. X.; Caminha, G. B.; Cypriano, E.; Cibirka, N.; Pereira, M. E. S.; Bom, C. R. D.; Lima, M. P.; Brandt, C. H.; Neto, A. F.; Estrada, J.; Lin, H.; Hao, J.; McKay, T. M.; da Costa, L. N.; Maia, M. A. G.

    2014-10-01

    We present the first results of the SOAR Gravitational Arc Survey (SOGRAS). The survey imaged 47 clusters in two redshift intervals centered at z=0.27 and z=0.55, targeting the richest clusters in each interval. Images were obtained in the g', r' and i' bands with a median seeing of 0.83, 0.76 and 0.71 arcsec, respectively, in these filters. Most of the survey clusters are located within the Sloan Digital Sky Survey (SDSS) Stripe-82 region and all of them are in the SDSS footprint. We present the first results of the survey, including the 6 best strong lensing systems, photometric and morphometric catalogs of the galaxy sample, and cross matches of the clusters and galaxies with complementary samples (spectroscopic redshifts, photometry in several bands, X-ray and Sunyaev Zel'dovich clusters, etc.), exploiting the synergy with other surveys in Stripe-82. We apply several methods to characterize the gravitational arc candidates, including the Mediatrix method (Bom et al. 2012) and ArcFitting (Furlanetto et al. 2012), and for the subtraction of galaxy cluster light. Finally, we apply strong lensing inversion techniques to the best systems, providing constraints on their mass distribution. The analyses of a spectral follow-up with Gemini and the derived dynamical masses are presented in a poster submitted to this same meeting (Cibirka et al.). Deeper follow-up images with Gemini strengthen the case for the strong lensing nature of the candidates found in this survey.

  7. Radioactive waste combustion / vitrification under arc plasma: thermal and dynamic modelling; Combustion - vitrification de dechets radioactifs par plasma d'arc: modelisation de la thermique et de la dynamique

    Energy Technology Data Exchange (ETDEWEB)

    Barthelemy, B

    2003-07-01

    This thesis concerns the thermal and dynamic modelling for a combustion/vitrification process of surrogate radioactive waste under transferred arc plasma. The writer presents the confinement processes for radioactive waste using arc plasma and the different software used to model theses processes. This is followed by a description of our experimental equipment including a plasma arc reactor and an inductive system allowing the homogenization of glass temperature. A combustion/vitrification test is described. Thermal and material balances were discussed. The temperature fields of plasma arc and the glass frit conductivity are measured. Finally, the writer describes and clarifies the equations solved for the simulations of the electrically plasma arc and the glass melting including the thin layer of glass frit coating the crucible cold walls. The modelling results are presented in the form of spatial distribution of temperature, velocity and volume power... (author)

  8. Radioactive waste combustion-vitrification under arc plasma: thermal and dynamic modelling; Combustion - vitrification de dechets radioactifs par plasma d'arc: modelisation de la thermique et de la dynamique

    Energy Technology Data Exchange (ETDEWEB)

    Barthelemy, B

    2003-06-01

    This thesis concerns the thermal and dynamic modelling for a combustion/vitrification process of surrogate radioactive waste under transferred arc plasma. The writer presents the confinement processes for radioactive waste using arc plasma and the different software used to model theses processes. This is followed by a description of our experimental equipment including a plasma arc reactor and an inductive system allowing the homogenization of glass temperature. A combustion/vitrification test is described. Thermal and material balances were discussed. The temperature fields of plasma arc and the glass frit conductivity are measured. Finally, the writer describes and clarifies the equations solved for the simulations of the electrically plasma arc and the glass melting including the thin layer of glass frit coating the crucible cold walls. The modelling results are presented in the form of spatial distribution of temperature, velocity and voluminal power... (author)

  9. Radar observations in the vicinity of pre-noon auroral arcs

    Directory of Open Access Journals (Sweden)

    H. Nilsson

    2005-07-01

    Full Text Available A combination of EISCAT incoherent scatter radar measurements, optical and magnetometer data is used to study the plasma in and around pre-noon structured precipitation and auroral arcs. Particular attention is paid to regions of comparatively low E-region density observed adjacent to arcs or structured precipitation in the EISCAT Svalbard radar field-aligned measurements. Comparison between luminosity and incoherent scatter electron density measurements shows that the low-density regions occur primarily due to the absence of diffuse precipitation rather than to a cavity formation process. Two cases of arcs and low density/luminosity regions are identified. The first is related to a strong Pc5 pulsation event, and the absence of diffuse precipitation is due to a large-scale modulation of the diffuse precipitation. In the second case the equatormost arc is on a shielding boundary and the low-density region coincides with a strong flow region just poleward of this arc. Regions of high electric field and low luminosity and conductance are observed prior to intensification of the structured precipitation in both cases. The ionospheric current is enhanced in the low conductance region, indicating that the strong electric fields do not result solely from ionospheric polarization electric fields, and thus are mainly driven by magnetospheric processes. The average energy of the precipitating electrons in the arcs and structured precipitation is, according to EISCAT measurements, 500eV and the energy spectra are similar for the pulsation and shielding cases. The average energy is thus significantly less than in the diffuse precipitation region which shows central CPS-like energy spectra. We suggest that the low ionospheric conductance of 0.7S in the low density regions is favorable for the arc formation process. This is in quantitative agreement with recent simulations of the ionospheric feedback instability. Keywords. Magnetospheric physics (Auroral

  10. Effects of aluminium doping on zinc oxide transparent thin films grown by filtered vacuum arc deposition

    Energy Technology Data Exchange (ETDEWEB)

    Gontijo, L.C., E-mail: pleooog@gmail.com [Instituto Federal do Espirito Santo, Programa de Pos-Graduacao em Engenharia Metalurgica e de Materiais, Av. Vitoria, 1729, Jucutuquara, 29040-780, Vitoria, ES (Brazil); Machado, R., E-mail: rogerio.machado.2l@gmail.com [Universidade Federal de Sergipe, Departamento de Fisica, Rod. Mal Rondon S/N, Jd Rosa Elze, CEP 49.100-000, Sao Cristovao, SE (Brazil); Nascimento, V.P., E-mail: valberpn@yahoo.com.br [Universidade Federal do Espirito Santo, Departamento de Fisica, Av. Fernando Ferrari, 514 Goiabeiras, CEP 29075-910, Vitoria, ES (Brazil)

    2012-06-25

    Highlights: Black-Right-Pointing-Pointer AZO films prepared by filtered vacuum arc deposition. Black-Right-Pointing-Pointer Systematic variation of Al concentration. Black-Right-Pointing-Pointer Structural, electrical and optical properties analyzed. Black-Right-Pointing-Pointer Optimized system for Al concentration between 4% and 6%. - Abstract: Thin n-type ZnO films doped with different atomic concentrations of aluminium were grown by filtered vacuum arc deposition (FVAD) on glass substrates. The films were deposited using an oxygen working pressure of 2.0 mTorr with an arc current running at two 100 ms pulses s{sup -1}. Structural, optical and electrical properties were investigated to understand the effect of Al doping on ZnO films. The best values were found for an ideal aluminium percentage between 4 and 6 at.%.

  11. Prototype arc saw design and cutting trials

    International Nuclear Information System (INIS)

    Allison, G.S.

    1980-09-01

    A program was initiated to develop the arc saw as a tool capable of removing the end fittings from spent nuclear fuel bundles. A special arc saw for this purpose was designed, installed at the Pacific Northwest Laboratory and satisfactorily operated to remove end fittings from simulated, nonradioactive fuel bundles. The design of the arc saw included consideration of the cutting environment, power supply size, control equipment, and work piece size. Several simulated fuel bundles were cut to demonstrate that the arc saw met design specifications. Although the arc saw development program was curtailed before significant performance data could be collected, tests indicate that the arc saw is a good means of cropping spent fuel bundles and is well suited to remote operation and maintenance

  12. Interaction mechanism in hybrid laser arc welding

    OpenAIRE

    Mahrle, Achim; Rose, Sascha; Lohse, Martin; Beyer, Eckhard; Füssel, Uwe

    2014-01-01

    Achievable benefits in hybrid laser-arc welding are closely related to suitable parameter settings. Basic optimizations consequently need a profound understanding of the relevance of involved interaction mechanisms. These are however differently evaluated and discussed in literature. This paper gives an overview on the most popular hypotheses in the field of laser-arc processing. The importance of direct interactions between laser radiation and arc plasma as well as the role of metal evaporat...

  13. Arc saw and its application to decommissioning

    International Nuclear Information System (INIS)

    Deichelbohrer, P.R.

    1982-01-01

    The arc saw is a toothless, circular saw that cuts by arc erosion. A model was built to study the arc saw's usefulness in cutting up radioactively contaminated metal scrap. It was chosen because it cuts with very little contact to the work piece and because cutting is not affected by material hardness. After installation of several improvements it was found it could cut almost any combination of metals and that clamping or fixturing requirements were minimum. Cutting proceeds rapidly and efficiently

  14. Programming ArcGIS with Python cookbook

    CERN Document Server

    Pimpler, Eric

    2015-01-01

    Programming ArcGIS with Python Cookbook, Second Edition, is written for GIS professionals who wish to revolutionize their ArcGIS workflow with Python. Whether you are new to ArcGIS or a seasoned professional, you almost certainly spend time each day performing various geoprocessing tasks. This book will teach you how to use the Python programming language to automate these geoprocessing tasks and make you a more efficient and effective GIS professional.

  15. Diffuse and spot mode of cathode arc attachments in an atmospheric magnetically rotating argon arc

    International Nuclear Information System (INIS)

    Chen, Tang; Wang, Cheng; Liao, Meng-Ran; Xia, Wei-Dong

    2016-01-01

    A model including the cathode, near-cathode region, and arc column was constructed. Specifically, a thermal perturbation layer at the arc fringe was calculated in order to couple sheath/presheath modelling with typical arc column modelling. Comparative investigation of two modes of attachment of a dc (100, 150, 200 A) atmospheric-pressure arc in argon to a thermionic cathode made of pure tungsten was conducted. Computational data revealed that there exists two modes of arc discharge: the spot mode, which has an obvious cathode surface temperature peak in the arc attachment centre; and the diffuse mode, which has a flat cathode surface temperature distribution and a larger arc attachment area. The modelling results of the arc attachment agree with previous experimental observations for the diffuse mode. A further 3D simulation is obviously needed to investigate the non-axisymmetrical features, especially for the spot mode. (paper)

  16. Modelling of plasma generation and expansion in a vacuum arc: application to the vacuum arc remelting process

    International Nuclear Information System (INIS)

    Chapelle, P.; Bellot, J.P.; Duval, H.; Jardy, A.; Ablitzer, D.

    2002-01-01

    As part of a complete theoretical description of the behaviour of the electric arc in the vacuum arc remelting process, a model has been developed for the column of plasma generated by a single cluster of cathode spots. The model combines a kinetic approach, taking into account the formation of the plasma in the cathodic region, and a hydrodynamic approach, describing the expansion of the plasma in the vacuum between the electrodes. The kinetic model is based on a system of Boltzmann-Vlasov-Poisson equations and uses a particle-type simulation procedure, combining the PIC (particle in cell) and FPM (finite point set method) methods. In the two-dimensional hydrodynamic model, the plasma is assimilated to a mixture of two continuous fluids (the electrons and the ions), each described by a system of coupled transport equations. Finally, a simplified method has been defined for calculating the electric current density and the energy flux density transmitted by the plasma to the anode. The results of the numerical simulation presented are consistent with a certain number of experimental data available in the literature. In particular, the model predicts a percentage of the electric power of the cluster transmitted to the anode (25%) in good agreement with the value indicated in the literature. (author)

  17. The Abundance of Large Arcs From CLASH

    Science.gov (United States)

    Xu, Bingxiao; Postman, Marc; Meneghetti, Massimo; Coe, Dan A.; Clash Team

    2015-01-01

    We have developed an automated arc-finding algorithm to perform a rigorous comparison of the observed and simulated abundance of large lensed background galaxies (a.k.a arcs). We use images from the CLASH program to derive our observed arc abundance. Simulated CLASH images are created by performing ray tracing through mock clusters generated by the N-body simulation calibrated tool -- MOKA, and N-body/hydrodynamic simulations -- MUSIC, over the same mass and redshift range as the CLASH X-ray selected sample. We derive a lensing efficiency of 15 ± 3 arcs per cluster for the X-ray selected CLASH sample and 4 ± 2 arcs per cluster for the simulated sample. The marginally significant difference (3.0 σ) between the results for the observations and the simulations can be explained by the systematically smaller area with magnification larger than 3 (by a factor of ˜4) in both MOKA and MUSIC mass models relative to those derived from the CLASH data. Accounting for this difference brings the observed and simulated arc statistics into full agreement. We find that the source redshift distribution does not have big impact on the arc abundance but the arc abundance is very sensitive to the concentration of the dark matter halos. Our results suggest that the solution to the "arc statistics problem" lies primarily in matching the cluster dark matter distribution.

  18. Performance tracking under ARCS contracts. Directive

    International Nuclear Information System (INIS)

    1992-01-01

    The directive discusses the development of a non-resource intensive method for reporting performance based work allocation results under the ARCS (Alternative Remedial Contracting Strategy) contractors

  19. DC switch power supply for vacuum-arc coatings deposition

    International Nuclear Information System (INIS)

    Zalesskij, D.Yu.; Volkov, Yu.Ya.; Vasil'ev, V.V.; Kozhushko, V.V.; Luchaninov, A.A.; Strel'nitskij, V.E.

    2008-01-01

    Special DC Switch Power Supply for vacuum-arc deposition was developed and tested in the mode of depositing Al and AlN films. Maximum output power was 6 kW, maximum output current - 120 A, open-circuit voltage - 150 V. The Power Supply allows to adjust and stabilize output current in a wide range. Testing of the Power Supply revealed an advantages over the standard 'Bulat-6' power supply, especially for deposition of non-conductive AlN films.

  20. A comparison of the seismic structure of oceanic island arc crust and continental accreted arc terranes

    Science.gov (United States)

    Calvert, A. J.

    2015-12-01

    Amalgamation of island arcs and their accretion to pre-existing continents is considered to have been one of the primary mechanisms of continental growth over the last 3 Ga, with arc terranes identified within Late Archean, Proterozoic, and Phanerozoic continental crust. Crustal-scale seismic refraction surveys can provide P wave velocity models that can be used as a proxy for crustal composition, and although they indicate some velocity variation in accreted arcs, these terranes have significantly lower velocities, and are hence significantly more felsic, than modern island arcs. Modern oceanic arcs exhibit significant variations in crustal thickness, from as little as 10 km in the Bonin arc to 35 km in the Aleutian and northern Izu arcs. Although globally island arcs appear to have a mafic composition, intermediate composition crust is inferred in central America and parts of the Izu arc. The absence of a sharp velocity contrast at the Moho appears to be a first order characteristic of island arc crust, and indicates the existence of a broad crust-mantle transition zone. Multichannel seismic reflection surveys complement refraction surveys by revealing structures associated with variations in density and seismic velocity at the scale of a few hundred meters or less to depths of 60 km or more. Surveys from the Mariana and Aleutian arcs show that modern middle and lower arc crust is mostly non-reflective, but reflections are observed from depths 5-25 km below the refraction Moho suggesting the localized presence of arc roots that may comprise gabbro, garnet gabbro, and pyroxenite within a broad transition from mafic lower crust to ultramafic mantle. Such reflective, high velocity roots are likely separated from the overlying arc crust prior to, or during arc-continent collision, and seismic reflections within accreted arc crust document the collisional process and final crustal architecture.

  1. Ecton processes in vacuum arc

    International Nuclear Information System (INIS)

    Mesyats, G.A.

    1995-01-01

    It is established that when microexplosions occur on a cathode there is a so-called explosive electron emission (EEE) observed. Such an emission is realized through individual short portions (the electron avalanches) which we have named open-quotes ectonsclose quotes. The duration of electron current of such a portion is dictated by the time needed to cool down the emission center, that causes the EEE to stop. We will proceed from the assumption of Kesaev, that the cathode spot consists of separate cells from which the current i n , equal to the doubled arc current i m , is flowing. An ecton is formed by interaction between the liquid metal stream and plasma. When the current exceeds a certain threshold value, the liquid metal stream produces a drop. This drop, even before its break-off, leads to the increase in density of the ion current from plasma in the stream-drop joint. This results in a great energy concentration in the joint and initiates an ecton due to the Joule heating of the joint. We consider the arc cycle to consist of two processes. The first one, of a duration t e , is the process of ecton operation. The second one, of a duration t i , is due to the ion current flowing within the cathode region. During the t i period the formation of a new liquid metal stream is completed, which causes a new ecton to emerge. The process thus becomes self-sustaining. If the new ecton is produced, with a drop breaking-off, then the criterion for the arc cycle to be self-sustaining is written as γd t i m ≥ 1

  2. Electric propulsion for small satellites

    Science.gov (United States)

    Keidar, Michael; Zhuang, Taisen; Shashurin, Alexey; Teel, George; Chiu, Dereck; Lukas, Joseph; Haque, Samudra; Brieda, Lubos

    2015-01-01

    Propulsion is required for satellite motion in outer space. The displacement of a satellite in space, orbit transfer and its attitude control are the task of space propulsion, which is carried out by rocket engines. Electric propulsion uses electric energy to energize or accelerate the propellant. The electric propulsion, which uses electrical energy to accelerate propellant in the form of plasma, is known as plasma propulsion. Plasma propulsion utilizes the electric energy to first, ionize the propellant and then, deliver energy to the resulting plasma leading to plasma acceleration. Many types of plasma thrusters have been developed over last 50 years. The variety of these devices can be divided into three main categories dependent on the mechanism of acceleration: (i) electrothermal, (ii) electrostatic and (iii) electromagnetic. Recent trends in space exploration associate with the paradigm shift towards small and efficient satellites, or micro- and nano-satellites. A particular example of microthruster considered in this paper is the micro-cathode arc thruster (µCAT). The µCAT is based on vacuum arc discharge. Thrust is produced when the arc discharge erodes some of the cathode at high velocity and is accelerated out the nozzle by a Lorentz force. The thrust amount is controlled by varying the frequency of pulses with demonstrated range to date of 1-50 Hz producing thrust ranging from 1 µN to 0.05 mN.

  3. No hexavalent half-arc-transitive graphs of order twice a prime ...

    Indian Academy of Sciences (India)

    39

    Let G be a permutation group on a set Ω and α ∈ Ω. Denoted by Gα the stabilizer .... the vertex-stabilizer Av of v ∈ V (Γ) in A is a {2,3}-group and Pv = P ∩ Av = 1. ..... power, J. Aust. Math. Soc. 81 (2006) 153–164. [13] Feng Y Q, Kwak J H, Xu M Y and Zhou J X, Tetravalent half-arc-transitive graphs of order p4, European J.

  4. Analogue modeling of arc and backarc deformation in the New Hebrides arc and North Fiji Basin

    NARCIS (Netherlands)

    Schellart, W. P.; Lister, G. S.; Jessell, M. W.

    In most backarc basins, extension is perpendicular to the arc. Thus individual spreading ridges extend approximately parallel to the arc. In the North Fiji Basin, however, several ancient and active spreading ridges strike 70°-90° to the New Hebrides arc. These high-angle spreading ridges relocated

  5. Hybrid Laser-Arc Welding of the High-Strength Shipbuilding Steels: Equipment and Technology

    Science.gov (United States)

    Turichin, G.; Kuznetsov, M.; Tsibulskiy, I.; Firsova, A.

    Hybrid laser-arc welding (HLAW) allows getting weld joints with thickness up to 35 mm for one pass, provide good quality formation of joints, minimal thermal deformations, the productivity in 10 times more in comparison with arc welding. In addition, replacement arc welding to the HLAW allows economizing filler materials, shielding gas and consumable electricity more than 4 times. Therefore, HLAW is actually technology for basic engineering branches and especially for shipbuilding. The Institute of Laser and Welding Technologies (ILWT) developed laser and hybrid laser-arc welding technologies for different type of steels and alloys including high-strength shipbuilding steels. Also ILWT produced portal and robotic systems for HLAW process realization. Portal system for hybrid laser-arc welding of panels with dimensions 6x6 m using at the manufacturing of flat curvilinear sections in the shipbuilding is depicted in the article. Results of experimental researches of the hybrid laser-arc welding parameters influence on the formation and mechanical properties of weld joint are described at the publication also. Experimental part was made with using of the portal system.

  6. Utilization of steel melting electric arc furnace slag for development ...

    Indian Academy of Sciences (India)

    Administrator

    road construction are the only utilization. This slag has been tried to be value added and utilized to ... aggregate in road constructions (Fallman and Kartlen. 1997; Lind et al 2000; Nagataki et al 2000). ..... furnace steel slag in road construction, in Characterization of residues release of contaminants from slag ash ashes (ed.).

  7. Energy characteristics of an electric-arc heater for tetrafluoromethane

    International Nuclear Information System (INIS)

    Timoshevskii, A.; Pozdnyakov, B.; Ponkratov, V.

    1998-01-01

    Plasma torches working on argon, hydrogen, air, methane and nitrogen have been described extensively in the literature, but there is almost no data on compositions with fluorine. For example, a plasma torch with tetrafluoromethane as a working gas may be of considerable interest for chemical industry

  8. Utilization of steel melting electric arc furnace slag for development ...

    Indian Academy of Sciences (India)

    Administrator

    batch of each composition was prepared by wet milling in a pot mill for 6 h at a speed of 35 rpm. The slurries were dried and disintegrated. Dry powders were thoroughly mixed with 5–6 ... Instron 5500 R machine was utilized to determine fle- xural strength. Acid and alkali resistance of the samples were tested as per Indian ...

  9. Evaluating optical hazards from plasma arc cutting.

    Science.gov (United States)

    Glassford, Eric; Burr, Gregory

    2018-01-01

    The Health Hazard Evaluation Program of the National Institute for Occupational Safety and Health evaluated a steel building materials manufacturer. The employer requested the evaluation because of concerns about optical radiation hazards from a plasma arc cutting system and the need to clarify eye protection requirements for plasma operators, other employees, and visitors. The strength of the ultraviolet radiation, visible radiation (light), and infrared radiation generated by the plasma arc cutter was measured at various distances from the source and at different operating amperages. Investigators also observed employees performing the plasma arc cutting. Optical radiation above safe levels for the unprotected eyes in the ultraviolet-C, ultraviolet-B, and visible light ranges were found during plasma arc cutting. In contrast, infrared and ultraviolet-A radiation levels during plasma arc cutting were similar to background levels. The highest non-ionizing radiation exposures occurred when no welding curtains were used. A plasma arc welding curtain in place did not eliminate optical radiation hazards to the plasma arc operator or to nearby employees. In most instances, the measured intensities for visible light, UV-C, and UV-B resulted in welding shade lens numbers that were lower than those stipulated in the OSHA Filter Lenses for Protection Against Radiant Energy table in 29 CFR 1910.133(a)(5). [1] Investigators recommended using a welding curtain that enclosed the plasma arc, posting optical radiation warning signs in the plasma arc cutter area, installing audible or visual warning cues when the plasma arc cutter was operating, and using welding shades that covered the plasma arc cutter operator's face to protect skin from ultraviolet radiation hazards.

  10. Evaluation of chemical stability, thermal expansion coefficient, and electrical properties of solid state and wet-chemical synthesized Y and Mn-codoped CeO2 for solid oxide fuel cells

    Science.gov (United States)

    Handal, Hala T.; Thangadurai, Venkataraman

    2013-12-01

    Chemical stability and high electrical conductivity under the operating conditions of solid oxide fuel cell (SOFC) are considered as the momentum for innovating solid electrolytes and electrodes. In this paper, we report synthesis, structure, chemical stability and electrical conductivity of novel co-doped Ce0.9-xY0.1MnxO2-δ (x = 0-15 mol%) (CYMO). X-ray diffraction of Mn and Y-doped CeO2 shows the formation of fluorite-type structure with a space group Fm-3m. A few weak peaks corresponding to a tetragonal Mn3O4 phase has been detected in some samples. Solubility of Mn in ceria is explained by considering the influence of the ionic radius, the crystal structure and its electronic structure. Thermal analysis shows dissimilarity between the reduction behavior of Ce0.9Mn0.1O2-δ and Ce0.9-xY0.1MnxO2-δ. Ce0.8Y0.1Mn0.1O2-δ exhibited the highest conductivity of ∼6 × 10-2 S cm-1 and 0.15 S cm-1 at 700 °C in air and H2, respectively. Surface studies have confirmed the formation of S species upon exposure to 30 ppm H2S in H2 and a mechanism for S poisoning is presented.

  11. ATLAS DDM integration in ARC

    DEFF Research Database (Denmark)

    Behrmann, Gerd; Cameron, David; Ellert, Mattias

    2008-01-01

    The Nordic Data Grid Facility (NDGF) consists of Grid resources running ARC middleware in Denmark, Finland, Norway and Sweden. These resources serve many virtual organisations and contribute a large fraction of total worldwide resources for the ATLAS experiment, whose data is distributed and mana......The Nordic Data Grid Facility (NDGF) consists of Grid resources running ARC middleware in Denmark, Finland, Norway and Sweden. These resources serve many virtual organisations and contribute a large fraction of total worldwide resources for the ATLAS experiment, whose data is distributed...... and managed by the DQ2 software. Managing ATLAS data within NDGF and between NDGF and other Grids used by ATLAS (the Enabling Grids for E-sciencE Grid and the Open Science Grid) presents a unique challenge for several reasons. Firstly, the entry point for data, the Tier 1 centre, is physically distributed...... outside the worker node environment. Also, the service used for cataloging the location of data files is different from otherGrids but must still be useable by DQ2 and ATLAS users to locate data within NDGF. This paper presents in detail how we solve these issues to allow seamless access worldwide to data...

  12. Evaluation of microbial stability, bioactive compounds, physicochemical properties, and consumer acceptance of pomegranate juice processed in a commercial scale pulsed electric field system

    Science.gov (United States)

    This paper investigated the feasibility for pasteurizing raw pomegranate juice in a commercial scale pulsed electric field (PEF) system. The juice was processed in a commercial scale PEF processing system at 35 and 38 kV/cm for 281 µs at 55 degree C with a flow rate of 100 L/h. Effect of PEF process...

  13. Pulsed arc plasma jet synchronized with drop-on-demand dispenser

    Science.gov (United States)

    Mavier, F.; Lemesre, L.; Rat, V.; Bienia, M.; Lejeune, M.; Coudert, J.-F.

    2017-04-01

    This work concerns with the liquid injection in arc plasma spraying for the development of finely structured ceramics coatings. Nanostructured coatings can be now achieved with nanopowders dispersed in a liquid (SPS: Suspension Plasma Spraying) or with a salt dissolved into a liquid (SPPS: Solution Precursor Plasma Spraying) injected into the plasma jet. Controlling electric arc instabilities confined in non-transferred arc plasma torch is therefore a key issue to get reproducible coating properties. Adjustment of parameters with a mono-cathode arc plasma allows a new resonance mode called “Mosquito”. A pulsed arc plasma producing a periodic regular voltage signal with modulation of enthalpy is obtained. The basic idea is to synchronize the injection system with the arc to introduce the liquid material in each plasma oscillation in the same conditions, in order to control the plasma treatment of the material in-fly. A custom-developed pulsed arc plasma torch is used with a drop-on-demand dispenser triggered by the arc voltage. A delay is added to adjust the droplets emission time and their penetration into the plasma gusts. Indeed, the treatment of droplets is also shown to be dependent on this injection delay. A TiO2 suspension and an aqueous solution of aluminium nitrate were optimized to get ejectable inks forming individual droplets. The feasibility of the process was demonstrated for SPS and SPPS techniques. Coatings from the suspension and the solution were achieved. First synchronized sprayings show a good penetration of the droplets into the plasma. Coatings show a fine structure of cauliflowers shapes. The synchronization of the ejection allows a control of morphology and a better deposition efficiency. Further investigations will find the optimal operating parameters to show the full potential of this original liquid injection technique.

  14. High Electron Mobility and Ambient Stability in Solution-Processed Perylene-Based Organic Field-Effect Transistors : origin of the enhanced electrical performances

    NARCIS (Netherlands)

    Piliego, Claudia; Jarzab, Dorota; Gigli, Giuseppe; Chen, Zhihua; Facchetti, Antonio; Loi, Maria Antonietto

    2009-01-01

    Bottom-contact n-channel OFETs basedon spin-coated films of N,N'-1H,1H-perfluorobutyl dicyanoperylenediimide (PDI-FCN(2)) exhibit a saturation-regime mobility of 0.15 cm(2) V(-1) s(-1) in vacuum and good air stability. These performances are attributed to the high crystallinity and to the edge-on

  15. Contribution to the 3D time-dependent modeling of the arc dynamic behavior in a DC plasma spray torch; Contribution a la modelisation instationnaire et tridimensionnelle du comportement dynamique de l'arc dans une torche de projection plasma

    Energy Technology Data Exchange (ETDEWEB)

    Baudry, C

    2003-11-15

    This work is devoted to the tri-dimensional time-dependent modeling of the arc behavior in a plasma spray torch. It has been carried out in the fame of a collaboration with the Thermal Spray Laboratory of CEA-DAM, Le Ripault and the laboratory of Fluid Mechanics and Heat Transfers of EDF. After a summary of the operation modes of a DC plasma torch and the effect of anode erosion on the torch working, the structure of an electric arc is depicted as well as the main models of non-transferred electric arcs proposed in the literature. This review allows the determination of the main assumption and boundary conditions for a 'realistic' model of the electric arc. Then, the equations, assumptions and boundary conditions of the model we have developed are presented and, the CFD code ESTET 3.4 used to solve the model equations. The model is based on a specific value of the local electric field to predict the breakdown of the arc while its re-striking is favored by a hot gas column at the spot where the highest value of the electric field is calculated. This model gives a realistic prediction of the time-dependent arc behavior according to the plasma-forming gas nature and of the temperature and velocity of the gas flow at the nozzle exit. However, it overestimates the torch voltage and dimensions of the anode arc root attachment spot. (author)

  16. Plasma Arc Augmented CO2 laser welding

    DEFF Research Database (Denmark)

    Bagger, Claus; Andersen, Mikkel; Frederiksen, Niels

    2001-01-01

    In order to reduce the hardness of laser beam welded 2.13 mm medium strength steel CMn 250, a plasma arc has been used simultaneously with a 2.6 kW CO2 laser source. In a number of systematic laboratory tests, the plasma arc current, plasma gas flow and distance to the laser source were varied...

  17. The kinematical structure of gravitationally lensed arcs

    NARCIS (Netherlands)

    Moller, O; Noordermeer, E

    2006-01-01

    In this paper, the expected properties of the velocity fields of strongly lensed arcs behind galaxy clusters are investigated. The velocity profile along typical lensed arcs is determined by ray-tracing light rays from a model source galaxy through parametric cluster toy models consisting of

  18. The structure and singularities of arc complexes

    DEFF Research Database (Denmark)

    Penner, Robert

    A classical combinatorial fact is that the simplicial complex consisting of disjointly embedded chords in a convex planar polygon is a sphere. For any surface F with non-empty boundary, there is an analogous complex Arc(F) consisting of suitable equivalence classes of arcs in F connecting its bou...

  19. ArcForm - A multimodal notation

    DEFF Research Database (Denmark)

    Allsopp, Benjamin Brink

    ArcForm (AF) is a visual notation based on a new graph-like network structure. It supports a unique approach to labeling arcs and nodes to allow diverse and grammatically normal English (or other natural language) sentences to be embedded in the network (Allsopp, 2013). In doing this AF combines ...

  20. Feature extraction of arc tracking phenomenon

    Science.gov (United States)

    Attia, John Okyere

    1995-01-01

    This document outlines arc tracking signals -- both the data acquisition and signal processing. The objective is to obtain the salient features of the arc tracking phenomenon. As part of the signal processing, the power spectral density is obtained and used in a MATLAB program.