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Sample records for spark discharge pasd

  1. Generation of Nanoparticles by Spark Discharge

    NARCIS (Netherlands)

    Salman Tabrizi, N.

    2009-01-01

    Spark discharge is a method for producing nanoparticles from conductive materials. Besides the general advantages of nanoparticle synthesis in the gas phase, the method offers additional advantages like simplicity, compactness and versatility. The synthesis process is continuous and is performed at

  2. Enrichment of colloidal solutions by nanoparticles in underwater spark discharge

    International Nuclear Information System (INIS)

    Lopat'ko, K.; Aftandiliants, Y.; Veklich, A.; Boretskij, V.; Taran, N.; Batsmanova, L.; Trach, V.; Tugai, T.

    2015-01-01

    The underwater spark discharge between manganese granules was studied. Optical emission spectroscopy methods were used for diagnostics of such discharge plasma. The colloidal solution with manganese nanoparticles was produced by this discharge. The biological applications of this colloid were analyzed. The mechanism of metallic nanoparticle action and their transformation at interacting with biological objects were studied in Alternaria alternata culture

  3. Protection of neutral-beam-accelerator electrodes from spark discharges

    International Nuclear Information System (INIS)

    Praeg, W.F.

    1978-01-01

    The high-voltage (HV) electrodes of neutral beam sources (NBS's) must be protected from occasional sparks to ground. Spark currents can be limited with special transformers and reactors which introduce time delays that are long enough to quench the spark or to disconnect the energy source. A saturated time delay transformer (STDT) connected in series with the HV power supply detects spark faults and limits the current supplied by the power supply and its capacitance to ground; it also initiates spark quenching. Nonsaturated, longitudinal reactors limit the discharge current supplied by the energy stored in the circuit capacitance of the NBS filament and arc power supplies long enough to discharge this capacitance into a resistor. The design principles of these protective circuits are presented in this paper

  4. Protection of neutral-beam accelerator electrodes from spark discharges

    International Nuclear Information System (INIS)

    Praeg, W.F.

    1977-01-01

    The high-voltage (HV) electrodes of neutral beam sources (NBS's) must be protected from occasional sparks to ground. Spark currents can be limited with special transformers and reactors which introduce time delays that are long enough to quench the spark or to disconnect the energy source. A saturated time delay transformer (STDT) connected in series with the HV power supply detects spark faults and limits the current supplied by the power supply and its capacitance to ground; it also initiates spark quenching. Nonsaturated, longitudinal reactors limit the discharge current supplied by the energy stored in the circuit capacitance of the NBS filament and arc power supplies long enough to discharge this capacitance into a resistor. The design principles of these protective circuits are presented

  5. New particle detector - a spark counter with a localized discharge

    International Nuclear Information System (INIS)

    Laptev, V.D.; Pestov, Yu.N.; Petrovykh, N.V.; Sannikov, B.P.; Fedotovich, G.V.

    1978-01-01

    Described is a plane spark counter with a localized discharge, which provides better time and X-Y resolution over a large area and at a high counting speed. Unlike conventional counters, in case of puncture, voltage applied to the counter plates is taken off in a limited area round the discharge. Main characteristics of the counter with 0.1 mm gap between electrodes are given. It is shown that time resolution of spark counters with a localized discharge is better than that for other types of counters

  6. Multi-spark discharge system for preparation of nutritious water

    Science.gov (United States)

    Nakaso, Tetsushi; Harigai, Toru; Kusumawan, Sholihatta Aziz; Shimomura, Tomoya; Tanimoto, Tsuyoshi; Suda, Yoshiyuki; Takikawa, Hirofumi

    2018-01-01

    The nitrogen compound concentration in water is increased by atmospheric-pressure plasma discharge treatment. A rod-to-water electrode discharge treatment system using plasma discharge has been developed by our group to obtain water with a high concentration of nitrogen compounds, and this plasma-treated water improves the growth of chrysanthemum roots. However, it is difficult to apply the system to the agriculture because the amount of treated water obtained by using the system too small. In this study, a multi-spark discharge system (MSDS) equipped multiple spark plugs is presented to obtain a large amount of plasma-treated water. The MSDS consisted of inexpensive parts in order to reduce the system introduction cost for agriculture. To suppress the temperature increase of the spark plugs, the 9 spark plugs were divided into 3 groups, which were discharged in order. The plasma-treated water with a NO3- concentration of 50 mg/L was prepared using the MSDS for 90 min, and the treatment efficiency was about 6 times higher than that of our previous system. It was confirmed that the NO2-, O3, and H2O2 concentrations in the water were also increased by treating the water using the MSDS.

  7. Feasibility of X-ray laser by Underwater Spark Discharges

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Takaaki [Department of Nuclear Engineering, Hokkaido University, Sapporo, Hokkaido (Japan)

    2000-03-01

    The method of Underwater Spark Discharges(USD) is one of the most effective ways for generating extremely compressed atomic clusters (called itonic clusters or micro Ball Lightning(BL)). It is also associated with energetic X-rays, which are caused by the break up of the itonic electrons. Despite of low voltage discharges of about 50 V, the high energy X-rays up to 150 keV can be generated. This paper proposed two methods of generating X-ray laser by using micro BL: (1) micro BL on surfaces of regularly arrayed wire cathodes and (2) gas of micro BL generated by USD. (author)

  8. Synthesis of mixed metallic nanoparticles by spark discharge

    Science.gov (United States)

    Tabrizi, N. S.; Xu, Q.; van der Pers, N. M.; Lafont, U.; Schmidt-Ott, A.

    2009-07-01

    Short spark discharges (2 μs) were successfully applied to generate mixed particles a few nanometres in diameter by fast quenching. Alloyed Cr-Co electrodes were applied to demonstrate this. Further it was shown that if the anode and the cathode are different materials, the discharge process mixes the vapour of both materials, forming mixed nanoparticles. Electron microscopy (TEM, SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analyses were performed on the collected particles to study their size, morphology, composition and structure. The average compositions of the particles were measured by inductively coupled plasma (ICP). In addition, online measurements of the particle size distribution by mobility analysis were carried out. In the case of alloyed electrodes (Cr-Co), the relative concentration of the elements in the nanoparticulate sample was consistent with the electrode composition. When using electrodes of different metals (Au-Pd and Ag-Pd) the individual nanoparticles showed a range of mixing ratios. No surface segregation was observed in these mixed noble metal particles. Crystalline nanoparticulate mixed phases were found in all cases.

  9. Underwater spark discharge with long transmission line for cleaning horizontal wells

    Science.gov (United States)

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

    2017-06-01

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

  10. Nanosecond repetitively pulsed discharges in air at atmospheric pressure-the spark regime

    International Nuclear Information System (INIS)

    Pai, David Z; Lacoste, Deanna A; Laux, Christophe O

    2010-01-01

    Nanosecond repetitively pulsed (NRP) spark discharges have been studied in atmospheric pressure air preheated to 1000 K. Measurements of spark initiation and stability, plasma dynamics, gas temperature and current-voltage characteristics of the spark regime are presented. Using 10 ns pulses applied repetitively at 30 kHz, we find that 2-400 pulses are required to initiate the spark, depending on the applied voltage. Furthermore, about 30-50 pulses are required for the spark discharge to reach steady state, following initiation. Based on space- and time-resolved optical emission spectroscopy, the spark discharge in steady state is found to ignite homogeneously in the discharge gap, without evidence of an initial streamer. Using measured emission from the N 2 (C-B) 0-0 band, it is found that the gas temperature rises by several thousand Kelvin in the span of about 30 ns following the application of the high-voltage pulse. Current-voltage measurements show that up to 20-40 A of conduction current is generated, which corresponds to an electron number density of up to 10 15 cm -3 towards the end of the high-voltage pulse. The discharge dynamics, gas temperature and electron number density are consistent with a streamer-less spark that develops homogeneously through avalanche ionization in volume. This occurs because the pre-ionization electron number density of about 10 11 cm -3 produced by the high frequency train of pulses is above the critical density for streamer-less discharge development, which is shown to be about 10 8 cm -3 .

  11. Nanosecond repetitively pulsed discharges in air at atmospheric pressure—the spark regime

    Science.gov (United States)

    Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

    2010-12-01

    Nanosecond repetitively pulsed (NRP) spark discharges have been studied in atmospheric pressure air preheated to 1000 K. Measurements of spark initiation and stability, plasma dynamics, gas temperature and current-voltage characteristics of the spark regime are presented. Using 10 ns pulses applied repetitively at 30 kHz, we find that 2-400 pulses are required to initiate the spark, depending on the applied voltage. Furthermore, about 30-50 pulses are required for the spark discharge to reach steady state, following initiation. Based on space- and time-resolved optical emission spectroscopy, the spark discharge in steady state is found to ignite homogeneously in the discharge gap, without evidence of an initial streamer. Using measured emission from the N2 (C-B) 0-0 band, it is found that the gas temperature rises by several thousand Kelvin in the span of about 30 ns following the application of the high-voltage pulse. Current-voltage measurements show that up to 20-40 A of conduction current is generated, which corresponds to an electron number density of up to 1015 cm-3 towards the end of the high-voltage pulse. The discharge dynamics, gas temperature and electron number density are consistent with a streamer-less spark that develops homogeneously through avalanche ionization in volume. This occurs because the pre-ionization electron number density of about 1011 cm-3 produced by the high frequency train of pulses is above the critical density for streamer-less discharge development, which is shown to be about 108 cm-3.

  12. Apparatus for atmospheric pressure pin-to-hole spark discharge and uses thereof

    Science.gov (United States)

    Dobrynin, Danil V.; Fridman, Alexander; Cho, Young I.; Fridman, Gregory; Friedman, Gennady

    2016-12-06

    Disclosed herein are atmospheric pressure pin-to-hole pulsed spark discharge devices and methods for creating plasma. The devices include a conduit for fluidically communicating a gas, a plasma, or both, therethrough, portion of the conduit capable of being connected to a gas supply, and a second portion of the conduit capable of emitting a plasma; a positive electrode comprising a sharp tip; and a ground plate electrode. Disclosed are methods for treating a skin ulcer using non-thermal plasma include flowing a gas through a cold spark discharge zone simultaneously with the creation of a pulsed spark discharge to give rise to a non-thermal plasma emitted from a conduit, the non-thermal plasma comprising NO; and contacting a skin ulcer with said non-thermal plasma for sufficient time and intensity to give rise to treatment of the skin ulcer.

  13. Development of the discharge (spark) chamber in Japan in the 1950s

    International Nuclear Information System (INIS)

    Fukui, Shuji

    1989-01-01

    The paper, written by its Japanese inventor Shuji Fukui, describes the development of the discharge or spark chamber in Japan in the 1950s. Flash-tubes were used in air-shower cosmic-ray experiments and this led to his design of a neon hodoscope detector. By including the property of neon bulbs glowing the discharge chamber was born, after he observed localized discharges along the trajectories of cosmic-ray particles. (UK)

  14. Stable kilohertz spark discharges for high-efficiency conversion of methane to hydrogen and acetylene

    International Nuclear Information System (INIS)

    Li Xiaosong; Xu Yong; Wang Younian; Zhu Aimin; Lin Cankun; Shi Chuan

    2008-01-01

    Stable kilohertz spark discharges with a unique waveform of discharge current were studied for high-efficiency conversion of methane to hydrogen and acetylene at atmospheric pressure for the first time. Discharge stability was confirmed by the concentration variation in the product streams with 220 min discharge time using pure methane as the feed gas. Utilizing the stable kilohertz spark discharges, the hydrogen concentration in the product stream could be as high as 72.1 vol% at an energy cost of 6.7 eV per H 2 molecule produced and 81.5% of methane conversion. The acetylene concentration could reach 18.4 vol% at an energy cost of 21.2 eV per C 2 H 2 molecule produced and 70.3% of methane conversion. For methane conversion ranging from 51.9% to 81.5%, the energy costs were 6.6-10.7 eV per CH 4 molecule converted, 4.4-6.7 eV per H 2 molecule produced and 16.9-27.6 eV per C 2 H 2 molecule produced. This study showed the high-concentration production of CO x -free hydrogen and acetylene from methane at a low energy cost by stable kilohertz spark discharges

  15. Investigation of the Energy Balance in the Spark Discharge Generator for Nanoparticles Synthesis

    Science.gov (United States)

    Mylnikov, D. A.; Efimov, A. A.; Ivanov, V. V.

    2017-07-01

    In this paper we investigate the balance of energy in the discharge circuit of a spark discharge generator (SDG) for nanoparticles synthesis. The released energy consists of several parts: the energy in a discharge gap and the energy dissipated in the other elements of the circuit. In turn, in the gap a one part of the energy releases in preanode and precathode regions and the other part in an arc between electrodes. We measured these parts and proposed ways to optimize energy efficiency of the nanoparticles production.

  16. X-ray flash photography of spark discharges in layers of liquid

    Science.gov (United States)

    Germer, Rudolf K.

    2001-04-01

    When W. Schaaffs developed X-ray flash machines after World War II at Siemens in Germany, he used spark discharges in layers of liquid between solid plates as a nonmilitary test object. W. Schaaffs discovered the so-called compression ring in 1947 during his experiments with spark discharges. This paper discusses the construction of triode X-ray flash tubes, the evolution of the discharge into the vacuum of the tube and the tubes characteristics depending on this mechanism. It will be found, that the special geometry of the tube shows an important influence on the discharge. The electrons will need a long time to reach the anode while positive ions are strongly accelerated near the anode. The duration of the x-ray flash is limited by the size and speed of the evaporated material from the anode. In the second part of this paper the spark discharge in a layer of liquid between solid plates is described. With this spark discharge it is possible to produce a shock wave in the liquid which finally moves to a vortex. Faster waves propagate in the plates at both sides of the layer. The plate waves induce a low pressure region in front of the ring and there it is possible to detect cavitation bubbles. The spatial arrangement of these bubbles in the layer of liquid between the solid plates depends on the excitation strength of the pulse waves in the plates. Their amplitude depends on the distance to the spark. Thus in a single X-ray flash picture it is possible to study the distribution of the cavitation bubbles for different excitation power. The spatial arrangement of the bubbles can show a periodic structure or it might be chaotic. X-ray flash experiments of this phenomenon will be presented. A model for the birth of cavitation bubbles will be shown. It explains how seeds of phase changes can be distributed in space under special conditions. This idea might also be valid for controlling the crystal growth.

  17. Analysis on discharge process of a plasma-jet triggered gas spark switch

    Science.gov (United States)

    Weihao, TIE; Cui, MENG; Yuting, ZHANG; Zirang, YAN; Qiaogen, ZHANG

    2018-01-01

    The plasma-jet triggered gas switch (PJTGS) could operate at a low working coefficient with a low jitter. We observed and analyzed the discharge process of the PJTGS at the lowest working coefficient of 47% with the trigger voltage of 40 kV and the pulse energy of 2 J to evaluate the effect of the plasma jet. The temporal and spatial evolution and the optical emission spectrum of the plasma jet were captured. And the spraying delay time and outlet velocity under different gas pressures were investigated. In addition, the particle in cell with Monte Carlo collision was employed to obtain the particle distribution of the plasma jet varying with time. The results show that, the plasma jet generated by spark discharge is sprayed into a spark gap within tens of nanoseconds, and its outlet velocity could reach 104 m s-1. The plasma jet plays a non-penetrating inducing role in the triggered discharge process of the PJTGS. On the one hand, the plasma jet provides the initial electrons needed by the discharge; on the other hand, a large number of electrons focusing on the head of the plasma jet distort the electric field between the head of the plasma jet and the opposite electrode. Therefore, a fast discharge originated from the plasma jet is induced and quickly bridges two electrodes.

  18. Determination of trace amounts of impurities in molybdenum by spark source and glow discharge mass spectrometry

    International Nuclear Information System (INIS)

    Saito, Morimasa

    1994-01-01

    For the determination of trace and ultra-trace amounts of impurities in high-purity molybdenum, spark source mass spectrometry and glow discharge mass spectrometry were studied. In spark source mass spectrometry using the metal probe method, the liquid-helium cryogenic pump was used in order to protect the surface of the samples from oxidation. The theoretical relative sensitivity factors (Mo=1) calculated from physical properties were used. The analytical results obtained for molybdenum tablet and high-purity molybdenum were in good agreement with those obtained by other methods (atomic absorption spectrometry and others). In glow discharge mass spectrometry, the relative sensitivity factors were calculated by using the results obtained by spark source mass spectrometry and atomic absorption spectrometry, and this method was applied to the determination of ultra-trace amounts of impurities in ultra high-purity molybdenum and gave the satisfactory results. The detection limits (2σ, n=10) in the integration time of 600 s for U and Th were 0.6 ppb and 0.3 ppb, and the values for Al, Si, Cr, Mn and Cu were in the range of 10 ppb to 0.5 ppb. (author)

  19. Radiation-MHD simulations for the development of a spark discharge channel.

    Energy Technology Data Exchange (ETDEWEB)

    Niederhaus, John Henry; Jorgenson, Roy E.; Warne, Larry K.; Chen, Kenneth C.

    2017-04-01

    The growth of a cylindrical s park discharge channel in water and Lexan is studied using a series of one - dimensional simulations with the finite - element radiation - magnetohydrodynamics code ALEGRA. Computed solutions are analyzed in order to characterize the rate of growth and dynamics of the spark c hannels during the rising - current phase of the drive pulse. The current ramp rate is varied between 0.2 and 3.0 kA/ns, and values of the mechanical coupling coefficient K p are extracted for each case. The simulations predict spark channel expansion veloc ities primarily in the range of 2000 to 3500 m/s, channel pressures primarily in the range 10 - 40 GPa, and K p values primarily between 1.1 and 1.4. When Lexan is preheated, slightly larger expansion velocities and smaller K p values are predicted , but the o verall behavior is unchanged.

  20. Effects of improving current characteristics of spark discharge on underwater shock waves

    Directory of Open Access Journals (Sweden)

    O Higa

    2016-09-01

    Full Text Available We have been developing a food-processing device that uses underwater shock waves generated by spark discharges at an underwater spark gap. Underwater shock waves can be used in food processing for softening, fracturing and sterilization. These technologies are attracting attention because the food is not heated during processing, so it does not change flavour. In this study, we develop a rice-powder manufacturing system using the fracturing effect provided by underwater shock waves. Because rice grains are very hard, the process must be applied repeatedly using a momentary high pressure to fracture the grains. The fast repeated generation of shock waves should provide high pressures from low energies. Therefore, we aim to achieve higher pressures from low energies expended by the underwater gap discharge. We increase the pulse compression rate by decreasing the circuit impedance of the device and increasing the charging voltage. Using optical observations and a pressure sensor, we measure the high pressure developed by the underwater shock wave and the rise time of the discharge current. We find that we can decrease the rise time of the discharge current by 17% while maintaining the peak current, and simultaneously increase the high pressure of the underwater shock wave by 135%.

  1. Generation of NiTi nanoparticles via high voltage spark discharge in inert gas

    Science.gov (United States)

    Arzi, Moein; Sabzehparvar, Milad; Amin, Mohamad Hassan; Sadrnezhaad, Sayed Khatiboleslam

    2018-01-01

    Spark discharge method in inert gas, due to simplicity, no need for complex equipment and raw materials, ability to produce high-purity nanoparticles and mix metallic nanoparticles, is considered a susceptible method for the synthesis of nanoparticles with narrow size distribution. This method is capable to produce nanoparticles of electrical conductor materials and semiconductors. Also, with small changes in spark discharge system, this method can be capable to deposit thin layers of nanoparticles. Now, this method has been used for producing carbon, metal, alloy and metal oxide nanoparticles. Primary objective of this study was to construct a high voltage electrical discharge system. Next step was the synthesis of NiTi alloy nanoparticles in argon atmosphere, using the same Ni-50at%Ti alloy as electrodes. Characterization of NiTi nanoparticles by FESEM, EDX, DLS and HRTEM helps to determine the NiTi nanoparticles size distribution, morphology and composition. The results demonstrated primary nanoparticles ranging from 10 nm to 20 nm in size with a composition close to that of the electrodes.

  2. Effects of solution volume on hydrogen production by pulsed spark discharge in ethanol solution

    Science.gov (United States)

    Xin, Y. B.; Sun, B.; Zhu, X. M.; Yan, Z. Y.; Liu, H.; Liu, Y. J.

    2016-07-01

    Hydrogen production from ethanol solution (ethanol/water) by pulsed spark discharge was optimized by varying the volume of ethanol solution (liquid volume). Hydrogen yield was initially increased and then decreased with the increase in solution volume, which achieved 1.5 l/min with a solution volume of 500 ml. The characteristics of pulsed spark discharge were studied in this work; the results showed that the intensity of peak current, the rate of current rise, and energy efficiency of hydrogen production can be changed by varying the volume of ethanol solution. Meanwhile, the mechanism analysis of hydrogen production was accomplished by monitoring the process of hydrogen production and the state of free radicals. The analysis showed that decreasing the retention time of gas production and properly increasing the volume of ethanol solution can enhance the hydrogen yield. Through this research, a high-yield and large-scale method of hydrogen production can be achieved, which is more suitable for industrial application.

  3. Bacteriostatic Substrate by Conductivity Method and Electric Spark Discharge Method Combined with Electrospinning for Silver Dressing

    Directory of Open Access Journals (Sweden)

    Kuo-Hsiung Tseng

    2016-01-01

    Full Text Available This study uses the conductivity method, Electric Spark Discharge Method, and the electrospinning technique to develop a better silver-based antibacterial agent. The preparation process is free of chemical substances and also conforms to the green energy-saving process. The silver iodide was prepared in an iodine agar medium by using the conductivity method. Multiple bacteriostasis experiments showed that the molds grew in the position with iodine of the culture medium after 6 days, as well as in the position with silver iodide after 10 days. The results prove that silver iodide has better bacteriostatic ability than povidone iodine. The nanosilver colloid was prepared in the PVA solution by using the Electric Spark Discharge Method. UV-Vis, Zetasizer, and SEM-EDX analyses proved that the PVA solution contained nanosilver colloid with good suspension stability. Finally, the electrospinning technique was used to spin the PVA solution with nanosilver colloid into the PVA nanofibrous membrane. According to UV-Vis analysis, the absorption peak of this nanofibrous membrane is about 415 nm, meaning this nanofibrous membrane contains nucleate nanosilver colloid, and is very suitable for antiseptic dressing.

  4. Development of the study on a 'pseudo-spark' discharge applied to a switch development

    International Nuclear Information System (INIS)

    Bauville, Gerard

    1994-01-01

    This research thesis aimed at studying the behaviour and electric characteristics of a very short duration discharge, a 'pseudo-spark' discharge, during its conduction phase as this phase governs the post-discharge dielectric recovery. The author notably focuses on the opening opportunities provided by such a discharge structure during its natural extinction at the current zero passage. After a description of the physiognomy of switches present in power energy sources, the author describes physical processes of evolution for this type of discharge (formation mechanisms, importance of the cathodic cavity). Then, he presents the 'pseudo-spark' prototype, conditions of experimentation, disjunction tests, and the specific voltage measurement test. Experimental results are then presented for the different discharge development phases, and for different geometrical, physical and electrical parameters [fr

  5. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    OpenAIRE

    Pai , David ,; Lacoste , Deanna ,; Laux , C.

    2010-01-01

    International audience; In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determine...

  6. 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.

  7. Contribution to the study of 'Pseudo-spark' discharges applied to the realisation of latch devices

    International Nuclear Information System (INIS)

    Bauville, Gerard

    1994-01-01

    The objective of this research thesis is to study discharges growing from a hollow geometry of electrodes for pressures on the left side of the Paschen minimum. The study characterises the main conduction phase by experimentally determining the discharge voltage and current. Based on a numerical analysis, the author deduces some macroscopic characteristics such as voltage mean value, dissipated energy, with respect to the variation of various parameters such as gas pressure and nature, discharge duration, and electrode cavity geometries. After a first part on switches (technological applications, switches, pseudo-spark breakers), the author addresses the discharges (presentation of a 'pseudo-spark'-type discharge, involved physical mechanisms, methods of initiation of pseudo-spark discharges, triggering by a magnetic field pulse). The next part describes the test bench in a detailed way (electrodes, triggering system, electric configurations), and the last part reports the experimental study. It addresses the following issues: distribution of magnetic field lines, voltage drop, conjunction phase, discharge footprints on the surfaces, propagation rate, disjunction [fr

  8. Fractal disperse hydrogen sorption kinetics in spark discharge generated Mg/NbOx and Mg/Pd nanocomposites

    NARCIS (Netherlands)

    Anastasopol, A.; Pfeiffer, T.V.; Schmidt-Ott, A.; Mulder, F.M.; Eijt, S.W.H.

    2011-01-01

    Isothermal hydrogen desorption of spark discharge generated Mg/NbOx and Mg/Pd metal hydride nanocomposites is consistently described by a kinetic model based on multiple reaction rates, in contrast to the Johnson-Mehl-Avrami-Kolmogorov [M. Avrami, J. Phys. Chem. 9, 177 (1941); W. A. Johnson and R.

  9. Fabricating TiO2 nanocolloids by electric spark discharge method at normal temperature and pressure

    Science.gov (United States)

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

    2017-11-01

    In this study, TiO2 nanocolloids were successfully fabricated in deionized water without using suspending agents through using the electric spark discharge method at room temperature and under normal atmospheric pressure. This method was exceptional because it did not create nanoparticle dispersion and the produced colloids contained no derivatives. The proposed method requires only traditional electrical discharge machines (EDMs), self-made magnetic stirrers, and Ti wires (purity, 99.99%). The EDM pulse on time (T on) and pulse off time (T off) were respectively set at 50 and 100 μs, 100 and 100 μs, 150 and 100 μs, and 200 and 100 μs to produce four types of TiO2 nanocolloids. Zetasizer analysis of the nanocolloids showed that a decrease in T on increased the suspension stability, but there were no significant correlations between T on and particle size. Colloids produced from the four production configurations showed a minimum particle size between 29.39 and 52.85 nm and a zeta-potential between -51.2 and -46.8 mV, confirming that the method introduced in this study can be used to produce TiO2 nanocolloids with excellent suspension stability. Scanning electron microscopy with energy dispersive spectroscopy also indicated that the TiO2 colloids did not contain elements other than Ti and oxygen.

  10. Large-volume excitation of air, argon, nitrogen and combustible mixtures by thermal jets produced by nanosecond spark discharges

    Science.gov (United States)

    Stepanyan, Sergey; Hayashi, Jun; Salmon, Arthur; Stancu, Gabi D.; Laux, Christophe O.

    2017-04-01

    This work presents experimental observations of strong expanding thermal jets following the application of nanosecond spark discharges. These jets propagate in a toroidal shape perpendicular to the interelectrode axis, with high velocities of up to 30 m s-1 and over distances of the order of a cm. Their propagation length is much larger than the thermal expansion region produced by the conventional millisecond sparks used in car engine ignition, thus greatly improving the volumetric excitation of gas mixtures. The shape and velocity of the jets is found to be fairly insensitive to the shape of the electrodes. In addition, their spatial extent is found to increase with the number of nanosecond sparks and with the discharge voltage, and to decrease slightly with the pressure between 1 and 7 atm at constant applied voltage. Finally, this thermal jet phenomenon is observed in experiments conducted with many types of gas mixtures, including air, nitrogen, argon, and combustible CH4/air mixtures. This makes nanosecond repetitively pulsed discharges particularly attractive for aerodynamic flow control or plasma-assisted combustion because of their ability to excite large volumes of gas, typically about 100 times the volume of the discharge.

  11. Primordial Synthesis of Amines and Amino Acids in a 1958 Miller H2S-Rich Spark Discharge Experiment

    Science.gov (United States)

    Parker, Eric T.; Cleaves, Henderson J.; Dworkin, Jason P.; Glavin, Daniel P.; Callahan, Michael; Aubrey, Andrew; Lazcano, Antonio; Bada, Jeffrey L.

    2011-01-01

    Archived samples from a previously unreported 1958 Stanley Miller electric discharge experiment containing hydrogen sulfide (H2S) were recently discovered and analyzed using high-performance liquid chromatography and time-of-flight mass spectrometry. We report here the detection and quantification of primary amine-containing compounds in the original sample residues, which were produced via spark discharge using a gaseous mixture of H2S, CH4, NH3, and CO2. A total of 23 amino acids and 4 amines, including 7 organosulfur compounds, were detected in these samples. The major amino acids with chiral centers are racemic within the accuracy of the measurements, indicating that they are not contaminants introduced during sample storage. This experiment marks the first synthesis of sulfur amino acids from spark discharge experiments designed to imitate primordia! environments. The relative yield of some amino acids, in particular the isomers of aminobutyric acid, are the highest ever found in a spark discharge experiment. The simulated primordial conditions used by Miller may serve as a model for early volcanic plume chemistry and provide insight to the possible roles such plumes may have played in abiotic organic synthesis. Additionally, the overall abundances of the synthesized amino acids in the presence of H2S are very similar to the abundances found in some carbonaceous meteorites, suggesting that H2S may have played an important role in prebiotic reactions in early solar system environments.

  12. Comparison of Nitrogen Incorporation in Tholins Produced by FUV Irradiation and Spark Discharge

    Science.gov (United States)

    Horst, S. M.; DeWitt, H. L.; Trainer, M. G.; Tolbert, M. A.

    2012-01-01

    The discovery of very heavy ions (Coates et al., 2007) in Titan's thermosphere has dramatically altered our understanding of the processes involved in the formation of the complex organic aerosols that comprise Titan's characteristic haze. Before Cassini's arrival, it was believed that aerosol production began in the stratosphere where the chemical processes were predominantly initiated by FUV radiation. This understanding guided the design of Titan atmosphere simulation experiments. However, the energy environment of the thermosphere is significantly different than the stratosphere; in particular there is a greater flux of EUV photons and energetic particles available to initiate chemical reactions, including the destruction of N2. in the upper atmosphere. Using a High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS), we have obtained in situ composition measurements of aerosol particles (so'called "tholins") produced in CH4/N2 gas mixtures subjected to either FUV radiation (deuterium lamp, 115-400 nm) (Trainer et al., 2012) or a spark discharge. A comparison of the composition of tholins produced using the two different energy sources will be presented, in particular with regard to the variation in nitrogen content of the two types of tholin. Titan's aerosols are known to contain significant amounts of nitrogen (Israel et al., 2005) and therefore understanding the role of nitrogen in the aerosol chemistry is important to further our knowledge of the formation and evolution of aerosols in Titan's atmosphere.

  13. Miller-Urey spark-discharge experiments in the deuterium world

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Geoffrey J.T.; Surman, Andrew J.; McIver, Jim; Colon-Santos, Stephanie M.; Gromski, Piotr S.; Buchwald, Saskia; Suarez Marina, Irene; Cronin, Leroy [WestCHEM, School of Chemistry, University of Glasgow (United Kingdom)

    2017-07-03

    We designed and conducted a series of primordial-soup Miller-Urey style experiments with deuterated gases and reagents to compare the spark-discharge products of a ''deuterated world'' with the standard reaction in the ''hydrogenated world''. While the deuteration of the system has little effect on the distribution of amino acid products, significant differences are seen in other regions of the product-space. Not only do we observe about 120 new species, we also see significant differences in their distribution if the two hydrogen isotope worlds are compared. Several isotopologue matches can be identified in both, but a large proportion of products have no equivalent in the corresponding isotope world with ca. 43 new species in the D world and ca. 39 new species in the H world. This shows that isotopic exchange (the addition of only one neutron) may lead to significant additional complexity in chemical space under otherwise identical reaction conditions. (copyright 2017 The Authors. Published by Wiley-VCH Verlag GmbH and Co. KGaA.)

  14. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    Science.gov (United States)

    Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

    2010-05-01

    In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determined, with the notable result that there exists a minimum and maximum gap distance for its existence at a given ambient gas temperature. The minimum gap distance increases with decreasing gas temperature, whereas the maximum does not vary appreciably. To explain the experimental results, an analytical model is developed to explain the corona-to-glow (C-G) and glow-to-spark (G-S) transitions. The C-G transition is analyzed in terms of the avalanche-to-streamer transition and the breakdown field during the conduction phase following the establishment of a conducting channel across the discharge gap. The G-S transition is determined by the thermal ionization instability, and we show analytically that this transition occurs at a certain reduced electric field for the NRP discharges studied here. This model shows that the electrode geometry plays an important role in the existence of the NRP glow regime at a given gas temperature. We derive a criterion for the existence of the NRP glow regime as a function of the ambient gas temperature, pulse repetition frequency, electrode radius of curvature, and interelectrode gap distance.

  15. Reduced enthalpy of metal hydride formation for Mg-Ti nanocomposites produced by spark discharge generation.

    Science.gov (United States)

    Anastasopol, Anca; Pfeiffer, Tobias V; Middelkoop, Joost; Lafont, Ugo; Canales-Perez, Roger J; Schmidt-Ott, Andreas; Mulder, Fokko M; Eijt, Stephan W H

    2013-05-29

    Spark discharge generation was used to synthesize Mg-Ti nanocomposites consisting primarily of a metastable body-centered-cubic (bcc) alloy of Mg and Ti. The bcc Mg-Ti alloy transformed upon hydrogenation into the face-centered-cubic fluorite Mg1-yTiyHx phase with favorable hydrogen storage properties. Both metal and metal hydride nanocomposites showed a fractal-like porous morphology, with a primary particle size of 10-20 nm. The metal content of 70 atom % (at %) Mg and 30 at % Ti, consistently determined by XRD, TEM-EDS, and ICP-OES, was distributed uniformly across the as-prepared sample. Pressure-composition isotherms for the Mg-Ti-H nanocomposites revealed large differences in the thermodynamics relative to bulk MgH2, with a much less negative enthalpy of formation of the hydride as small as -45 ± 3 kJ/molH2 as deduced from van't Hoff plots. The plateau pressures of hydrogenation were substantially higher than those for bulk MgH2 in the low temperature range from 150 to 250 °C. The reaction entropy was simultaneously reduced to values down to 84 ± 5 J/K mol H2, following a linear relationship between the enthalpy and entropy. Plausible mechanisms for the modified thermodynamics are discussed, including the effect of lattice strains, the presence of interfaces and hydrogen vacancies, and the formation of excess free volume due to local deformations. These mechanisms all rely on the finely interdispersed nanocomposite character of the samples which is maintained by grain refinement.

  16. Investigation of a two-electrode gas switch with electrodynamical acceleration of spark channel in oscillatory regime of discharge

    Science.gov (United States)

    Kharlov, A. V.; Kovalchuk, B. M.; Kumpyak, E. V.; Tsoy, N. V.

    2017-10-01

    We have developed a compact gas switch intended for operation in oscillatory (low damping) regime of discharge. It is two-electrode switch with electrodynamic acceleration of a spark channel and a matched series injection trigger generator. A series inductance is employed for isolation of a trigger pulse from a surrounded circuit. Two operations regimes have been investigated, namely "fast" regime with current amplitude ~ 160 kA, total charge ~ 12 C, period of oscillations 60 μ s, full pulse length ~ 400 μ s and "slow" regime with current amplitude ~ 30 kA, total charge 18 C, period of oscillations 360 μ s, full pulse length ~ 3 ms. The spark gap can be triggered reliably from 16 to 50 kV (at 72 kV self-breakdown voltage). Time delay in firing was less than 35 ns at 1 ns jitter at 30 mm gap and 40 kV charging voltage. The spark gap is designed for 50 kV charging voltage, at a current up to 200 kA, and up to 20 C charge transfer. Arc motion and electrodes erosion in this spark gap have been investigated. The main results are as follows: the arc channel moves on ~ 18 cm in fast regime and ~ 25 cm in slow regime. Results of the switch operation in slow and fast regimes with operational voltage of 40 kV and stored energy 32 kJ promise to get high lifetime. In this paper we present design for the spark gap and trigger generator. Test bed schematics and results of the tests are also described.

  17. Application of Pulse Spark Discharges for Scale Prevention and Continuous Filtration Methods in Coal-Fired Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young; Fridman, Alexander

    2012-06-30

    The overall objective of the present work was to develop a new scale-prevention technology by continuously precipitating and removing dissolved mineral ions (such as calcium and magnesium) in cooling water while the COC could be doubled from the present standard value of 3.5. The hypothesis of the present study was that if we could successfully precipitate and remove the excess calcium ions in cooling water, we could prevent condenser-tube fouling and at the same time double the COC. The approach in the study was to utilize pulse spark discharges directly in water to precipitate dissolved mineral ions in recirculating cooling water into relatively large suspended particles, which could be removed by a self-cleaning filter. The present study began with a basic scientific research to better understand the mechanism of pulse spark discharges in water and conducted a series of validation experiments using hard water in a laboratory cooling tower. Task 1 of the present work was to demonstrate if the spark discharge could precipitate the mineral ions in water. Task 2 was to demonstrate if the selfcleaning filter could continuously remove these precipitated calcium particles such that the blowdown could be eliminated or significantly reduced. Task 3 was to demonstrate if the scale could be prevented or minimized at condenser tubes with a COC of 8 or (almost) zero blowdown. In Task 1, we successfully completed the validation study that confirmed the precipitation of dissolved calcium ions in cooling water with the supporting data of calcium hardness over time as measured by a calcium ion probe. In Task 2, we confirmed through experimental tests that the self-cleaning filter could continuously remove precipitated calcium particles in a simulated laboratory cooling tower such that the blowdown could be eliminated or significantly reduced. In addition, chemical water analysis data were obtained which were used to confirm the COC calculation. In Task 3, we conducted a series

  18. Photoionization in a Numerical Simulation of a Spark Discharge in Air

    Science.gov (United States)

    2016-09-01

    that this arc resistance can be questioned. A detailed numerical study of an arc came from the research on thunder and lightning .4 This study is......Introduction The electrical characteristics of an arc that is produced by a high-current pulse have been studied for spark gap switches, lightning and

  19. Spark discharge and flame inception analysis through spectroscopy in a DISI engine fuelled with gasoline and butanol

    Science.gov (United States)

    Irimescu, A.; Merola, S. S.

    2017-10-01

    Extensive application of downsizing, as well as the application of alternative combustion control with respect to well established stoichiometric operation, have determined a continuous increase in the energy that is delivered to the working fluid in order to achieve stable and repeatable ignition. Apart from the complexity of fluid-arc interactions, the extreme thermodynamic conditions of this initial combustion stage make its characterization difficult, both through experimental and numerical techniques. Within this context, the present investigation looks at the analysis of spark discharge and flame kernel formation, through the application of UV-visible spectroscopy. Characterization of the energy transfer from the spark plug’s electrodes to the air-fuel mixture was achieved by the evaluation of vibrational and rotational temperatures during ignition, for stoichiometric and lean fuelling of a direct injection spark ignition engine. Optical accessibility was ensured from below the combustion chamber through an elongated piston design, that allowed the central region of the cylinder to be investigated. Fuel effects were evaluated for gasoline and n-butanol; roughly the same load was investigated in throttled and wide-open throttle conditions for both fuels. A brief thermodynamic analysis confirmed that significant gains in efficiency can be obtained with lean fuelling, mainly due to the reduction of pumping losses. Minimal effect of fuel type was observed, while mixture strength was found to have a stronger influence on calculated temperature values, especially during the initial stage of ignition. In-cylinder pressure was found to directly determine emission intensity during ignition, but the vibrational and rotational temperatures featured reduced dependence on this parameter. As expected, at the end of kernel formation, temperature values converged towards those typically found for adiabatic flames. The results show that indeed only a relatively small part

  20. Synthesis and characterization of black amorphous titanium oxide nanoparticles by spark discharge method

    Science.gov (United States)

    Sabzehparvar, Milad; Kiani, Fatemeh; Tabrizi, Nooshin Salman

    2018-01-01

    In the last decade, while crystalline titanium oxide nanoparticles have been extensively studied, the studies on amorphous polymorph nanoparticles are relatively rare and limited to the ab initio studies. We have synthesized black amorphous titanium oxide nanoparticles using, for the first time, spark ablation in the argon gas followed by oxidation at atmospheric conditions. The produced nanoparticles were characterized by various characterization methods to study their structure, size, morphology, surface area and optical properties. XRD analysis indicated the formation of an amorphous TiO2 phase together with Ti, TiO and Ti2O3 crystalline phases. FESEM demonstrated that the produced nanoparticles had a narrow size distribution. EDS analysis suggested the formation of nonstoichiometric titanium oxide. TEM and SAED analyses showed that the majority of nanoparticles were in amorphous state and possessed an average size of about 5.2 nm. A very high specific surface area of 310 m2/g was measured for the produced nanoparticles by the BJH analysis. These titanium oxide nanoparticles showed an optical band gap of around 3.2eV and an enhanced absorption in the whole visible spectrum measured by the UV-Vis and DRS analyses due to the oxygen deficiency. These results indicate that the spark ablation in the gas phase is a facile method for the synthesis of black amorphous titanium oxide nanoparticles.

  1. Studies on discharges in Micro Pattern Gaseous Detectors, towards a spark resistant THGEM detector

    CERN Document Server

    Cantini, Cosimo; De Oliveira, Rui

    The problem afflicting any of MPGDs is the phenomenon of discharging which might be destructive in some highly energetic cases, at least being responsible of a slow aging of the detector. So far one solution has been cascading several gain elements (GEM, THGEM detectors) reducing the gain of each one; this method, spreading the charges along their path, reduce effectively the likelihood of a discharge but introduce more material due to the multiple stages of amplification. Our goal is developing a single stage THGEM detector which could withstand discharges, not reducing the gain, hence being still able to amplify low level ionizing particles while implementing some methodologies to reduce the damages due to discharge induced by high rate of particles’ flux and/or highly ionizing particles. This report describes the test bench set up to study discharges between simple structures, which are actually models of the bigger detector. The idea behind this approach is to reduce the complexity of the whole phenomen...

  2. Preparation of Ag/Cu/Ti Nanofluids by Spark Discharge System and Its Control Parameters Study

    Directory of Open Access Journals (Sweden)

    Kuo-Hsiung Tseng

    2015-01-01

    Full Text Available This study selected silver, copper, and titanium as the research objects to explore the relationship between nanofluids properties and electrical discharge machining (EDM processes. Regarding the products, UV-visible spectroscopy (UV-Vis was applied to measure the concentration distribution of nanofluids; zeta-size analysis is applied for measuring nanometal particles’ Zeta-Potential and the size distribution of metallic particles in the fluid. Finally, various instruments, including scanning electron microscope (SEM, were applied to observe the shape, size, and composition ratio of metal particles after processing. According to the experimental results, the control of the discharge pulse time, in addition to affecting the concentration of metallic liquid and temperature in the process, affects the size of the metal particles after the process. As the resistivity of silver and copper is very low, at about 15×10-9 Ω·m, if TON is set to between 10~50 μs, good preparation efficiency can be obtained. The resistivity of titanium is 420×10-9 Ω·m, which is much larger than that of silver or copper. Hence, TON should be set to approximately 100 μs to achieve a good discharge success rate.

  3. Electrical properties of airborne nanoparticles produced by a commercial spark-discharge generator

    Energy Technology Data Exchange (ETDEWEB)

    Bau, S., E-mail: sebastien.bau@inrs.fr; Witschger, O. [Laboratoire de Metrologie des Aerosols, Institut National de Recherche et de Securite, INRS (France); Gensdarmes, F. [IRSN, Laboratoire de Physique et de Metrologie des Aerosols, Institut de Radioprotection et de Surete Nucleaire (France); Thomas, D. [LSGC/CNRS, Nancy Universite, Laboratoire des Sciences du Genie Chimique (France); Borra, J.-P. [Equipe Decharges Electriques et Procedes Aerosols, Laboratoire de Physique des Gaz et des Plasmas (France)

    2010-08-15

    A nanoparticle generator based on the principle of electrical discharge (PALAS GFG-1000) was used to produce nanoparticles of different chemical natures. The fractions of electrically neutral particles were then measured by means of a Spectrometre de Mobilite Electrique Circulaire (SMEC, i.e. radial-flow mobility analyzer) for different operating conditions. The experimental results were compared with the theoretical values calculated from the Fuchs extended charge equilibrium model for spherical particles and agglomerates. For the smallest particles (below 20 nm), the deviations observed remain below 10%, and tend towards 20% for larger particles (over 35 nm).

  4. Electric spark discharges in water. Low-energy nuclear transmutations and light leptonic magnetic monopoles in an extended standard model

    Energy Technology Data Exchange (ETDEWEB)

    Stumpf, Harald [Tuebingen Univ. (Germany). Inst. of Theoretical Physics

    2017-11-01

    Light leptonic magnetic monopoles were predicted by Lochak [G. Lochak, Intern. J. Theor. Phys. 24, 1019 (1985).]. Experimental indications based on nuclear transmutations were announced by Urutskoiev et al. [L. I. Urutskoiev, V. I. Liksonov, V. G. Tsinoev, Ann. Fond. L. de Broglie 27, Nr.4, 791 (2002).] and Urutskoev [L. J. Urutskoev, Ann. Fond. L. de Broglie 29, 1149 (2004).]. A theoretical interpretation of these transmutations is proposed under the assumption that light leptonic magnetic monopoles are created during spark discharges in water. The latter should be excited neutrinos according to Lochak. This hypothesis enforces the introduction of an extended Standard Model described in previous papers. The most important results of this study are (i) that multiple proton captures are responsible for the variety of transmutations and that leptonic magnetic monopoles are involved in these processes (ii) that electromagnetic duality can be established for bound states of leptonic monopoles although massive monopoles are in general unstable (iii) that criteria for the emission of leptonic magnetic monopoles and for their catalytic effect on weak decays are set up and elaborated. The study can be considered as a contribution to the efforts of Urutskoiev and Lochak to understand the reasons for accidents in power plants.

  5. Electric Spark Discharges in Water. Low-energy Nuclear Transmutations and Light Leptonic Magnetic Monopoles in an Extended Standard Model

    Science.gov (United States)

    Stumpf, Harald

    2017-08-01

    Light leptonic magnetic monopoles were predicted by Lochak [G. Lochak, Intern. J. Theor. Phys. 24, 1019 (1985).]. Experimental indications based on nuclear transmutations were announced by Urutskoiev et al. [L. I. Urutskoiev, V. I. Liksonov, V. G. Tsinoev, Ann. Fond. L. de Broglie 27, Nr.4, 791 (2002).] and Urutskoev [L. J. Urutskoev, Ann. Fond. L. de Broglie 29, 1149 (2004).]. A theoretical interpretation of these transmutations is proposed under the assumption that light leptonic magnetic monopoles are created during spark discharges in water. The latter should be excited neutrinos according to Lochak. This hypothesis enforces the introduction of an extended Standard Model described in previous papers. The most important results of this study are (i) that multiple proton captures are responsible for the variety of transmutations and that leptonic magnetic monopoles are involved in these processes (ii) that electromagnetic duality can be established for bound states of leptonic monopoles although massive monopoles are in general unstable (iii) that criteria for the emission of leptonic magnetic monopoles and for their catalytic effect on weak decays are set up and elaborated. The study can be considered as a contribution to the efforts of Urutskoiev and Lochak to understand the reasons for accidents in power plants.

  6. INVESTIGATION OF CHANGES OF PHYSICAL AND CHEMICAL PROPERTIES OF TAP WATER UNDER INFLUENCE OF POWERFUL UNDERWATER SPARK DISCHARGES

    Directory of Open Access Journals (Sweden)

    D. V. Vinnikov

    2017-03-01

    Full Text Available Purpose. The purpose of this investigation is to study the changes in the redox potential and pH-value of the tap water as a function of underwater spark discharges, storage device capacitance and the charging voltage. Methodology. To define the electric parameters of discharge circuit we used the Rogowski loop and the compensated capacitance-ohm potential divider. To determine water properties before and after the treatment we used the following devices: the water analyzer Anion -7051 with the limit of absolute error of the EMF measurement ± 2 mV, the BANTE 902 device with the absolute error of ± 0.002 рН. Results. We managed to establish the time of the origination of changes in the properties of treated water. A change in the positive redox potential to a negative one occurred already after the third pulse at a total energy input of ≥ 1 kJ. The pH value increased in the range of 0.2 – 0.45 рН units. We obtained the relationship of a change in the redox potential as a function of total energy of the pulse train that actually exhibits the linear relation to the mass of erosion products. We established that the electrodes made of stainless steel and the electrodes made of graphite provide similar changes in water properties. An increase in pH is indicative of the progress of reactions that result in the formation of ОН‾. Originality. The obtained experimental data prove a rapid and reliable change in the redox potential from positive to negative changes in the redox potential exponent can persist during ten days and even longer. The erosion products of electrodes can be removed from the treated water using the method of magnetic separation. Practical value. The «HYDRA» plant can be used as the electrochemical ideal mixing reactor of a discrete action with the removal of erosion products of the electrode using the method of magnetic separation.

  7. SparkJet Efficiency

    Science.gov (United States)

    Golbabaei-Asl, Mona; Knight, Doyle; Anderson, Kellie; Wilkinson, Stephen

    2013-01-01

    A novel method for determining the thermal efficiency of the SparkJet is proposed. A SparkJet is attached to the end of a pendulum. The motion of the pendulum subsequent to a single spark discharge is measured using a laser displacement sensor. The measured displacement vs time is compared with the predictions of a theoretical perfect gas model to estimate the fraction of the spark discharge energy which results in heating the gas (i.e., increasing the translational-rotational temperature). The results from multiple runs for different capacitances of c = 3, 5, 10, 20, and 40 micro-F show that the thermal efficiency decreases with higher capacitive discharges.

  8. Observations and Modeling of Long Negative Laboratory Discharges: Identifying the Physics Important to an Electrical Spark in Air

    Energy Technology Data Exchange (ETDEWEB)

    Biagi, C J; Uman, M A

    2011-12-13

    There are relatively few reports in the literature focusing on negative laboratory leaders. Most of the reports focus exclusively on the simpler positive laboratory leader that is more commonly encountered in high voltage engineering [Gorin et al., 1976; Les Renardieres Group, 1977; Gallimberti, 1979; Domens et al., 1994; Bazelyan and Raizer 1998]. The physics of the long, negative leader and its positive counterpart are similar; the two differ primarily in their extension mechanisms [Bazelyan and Raizer, 1998]. Long negative sparks extend primarily by an intermittent process termed a 'step' that requires the development of secondary leader channels separated in space from the primary leader channel. Long positive sparks typically extend continuously, although, under proper conditions, their extension can be temporarily halted and begun again, and this is sometimes viewed as a stepping process. However, it is emphasized that the nature of positive leader stepping is not like that of negative leader stepping. There are several key observational studies of the propagation of long, negative-polarity laboratory sparks in air that have aided in the understanding of the stepping mechanisms exhibited by such sparks [e.g., Gorin et al., 1976; Les Renardieres Group, 1981; Ortega et al., 1994; Reess et al., 1995; Bazelyan and Raizer, 1998; Gallimberti et al., 2002]. These reports are reviewed below in Section 2, with emphasis placed on the stepping mechanism (the space stem, pilot, and space leader). Then, in Section 3, reports pertaining to modeling of long negative leaders are summarized.

  9. New spark test device for material characterization

    CERN Document Server

    Kildemo, Morten

    2004-01-01

    An automated spark test system based on combining field emission and spark measurements, exploiting a discharging capacitor is investigated. In particular, the remaining charge on the capacitor is analytically solved assuming the field emitted current to follow the Fowler Nordheim expression. The latter allows for field emission measurements from pA to A currents, and spark detection by complete discharge of the capacitor. The measurement theory and experiments on Cu and W are discussed.

  10. Formation of ROS and RNS in Water Electro-Sprayed through Transient Spark Discharge in Air and their Bactericidal Effects

    Czech Academy of Sciences Publication Activity Database

    Machala, Z.; Tarabová, B.; Hensel, K.; Doležalová, Eva; Šikurová, L.; Lukeš, Petr

    2013-01-01

    Roč. 10, č. 7 (2013), s. 649-659 ISSN 1612-8850 R&D Projects: GA AV ČR IAAX00430802; GA ČR(CZ) GD104/09/H080; GA MŠk(CZ) MEB0810116 Institutional support: RVO:61389021 Keywords : Plasma electrospray * water * bacteria * hydrogen peroxide * peroxynitrite * cold plasma * water electro-spray Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.964, year: 2013 http://dx.doi.org/10.1002/ppap.201200113

  11. Direct and controllable nitric oxide delivery into biological media and living cells by a pin-to-hole spark discharge (PHD) plasma

    Energy Technology Data Exchange (ETDEWEB)

    Dobrynin, D; Friedman, G [Electrical and Computer Engineering Department, College of Engineering, Drexel University, Philadelphia, PA (United States); Arjunan, K; Clyne, A Morss [School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA (United States); Fridman, A, E-mail: alisam@coe.drexel.edu [Department of Mechanical Engineering and Mechanics, College of Engineering, Drexel University, Philadelphia, PA (United States)

    2011-02-23

    Nitric oxide has great potential for improving wound healing through both inflammatory and vascularization processes. Nitric oxide can be produced in high concentrations by atmospheric pressure thermal plasmas. We measured the physical characteristics and nitric oxide production of a pin-to-hole spark discharge (PHD) plasma, as well as plasma-produced nitric oxide delivery into liquid and endothelial cells. The plasma temperature was calculated as 9030 {+-} 320 K by the Boltzmann method, which was adequate to produce nitric oxide, although the average gas temperature was near room temperature. The plasma produced significant UV radiation and hydrogen peroxide, but these were prevented from reaching the cells by adding a straight or curved tube extension to the plasma device. Plasma-produced nitric oxide in gas reached 2000 ppm and rapidly diffused into liquid and cells. Cells remained viable following plasma treatment and showed a linear increase in cGMP concentration with plasma treatment, indicating an intracellular functional response to PHD plasma NO. These data suggest that this plasma may provide a novel method for delivering NO locally and directly for enhanced wound healing.

  12. Spark Length and the Van de Graaff Generator

    OpenAIRE

    Suthinand Jirakulpatana

    2007-01-01

    The maximum discharge spark length of a Van de Graaf generator as a function of belt speed was studied. It was found that the maximum spark length was proportional to the square root of the belt speed.

  13. Spark Length and the Van de Graaff Generator

    Directory of Open Access Journals (Sweden)

    Suthinand Jirakulpatana

    2007-06-01

    Full Text Available The maximum discharge spark length of a Van de Graaf generator as a function of belt speed was studied. It was found that the maximum spark length was proportional to the square root of the belt speed.

  14. Intershield to tank sparks at the Daresbury tandem

    International Nuclear Information System (INIS)

    James, A.N.

    1983-04-01

    The causes of serious metallic melting and denting due to discharges in the insulating gas of the Daresbury tandem are examined. In order to explain the melting, high oscillating currents have to flow in the spark channels, and those can only be expected when return strokes excite local electromagnetic modes at the site of the origin of breakdown. In the case of intershield to tank sparks, evidence that magnetic confinement of the spark channel produces denting is presented. A model which accounts for the differences between sparks at Oak Ridge and sparks at Daresbury is also presented. (author)

  15. Fastdata processing with Spark

    CERN Document Server

    Karau, Holden

    2013-01-01

    This book will be a basic, step-by-step tutorial, which will help readers take advantage of all that Spark has to offer.Fastdata Processing with Spark is for software developers who want to learn how to write distributed programs with Spark. It will help developers who have had problems that were too much to be dealt with on a single computer. No previous experience with distributed programming is necessary. This book assumes knowledge of either Java, Scala, or Python.

  16. Experimental study of the positive leader velocity as a function of the current in the initial and final-jump phases of a spark discharge

    International Nuclear Information System (INIS)

    Andreev, A. G.; Bazelyan, E. M.; Bulatov, M. U.; Kuzhekin, I. P.; Makalsky, L. M.; Sukharevskij, D. I.; Syssoev, V. S.

    2008-01-01

    A positive leader in air at gap lengths of up to 8 m was studied experimentally on an open experimental stand. The voltage source was a 6-MV pulsed voltage generator or an artificial charged aerosol cloud. The dependence of the leader velocity on the current in the range 0.2-8 A was determined by simultaneously recording the optical picture and electric parameters of the discharge. Particular attention was paid to the final-jump phase of the discharge, when the gap was completely bridged by the streamer zone of the leader. It is shown that the character of the dependence of the leader velocity on the current in this phase remains unchanged; hence, the final-jump phase can be used in experiments in which the current has to be varied within a wide range. For this purpose, one can use a damping resistance, which is inefficient in the initial phase. The parameters of the power-law dependence of the leader velocity on the current at currents of a few amperes are established reliably. It is found that the power-law dependence with constant parameters is inapplicable to calculate the leader velocity at currents of about 0.1 A, which correspond to the lower limit of the leader viability.

  17. Magnetite Nanoparticles Prepared By Spark Erosion

    Directory of Open Access Journals (Sweden)

    Maiorov M.

    2016-08-01

    Full Text Available In the present research, we study a possibility of using the electric spark erosion method as an alternative to the method of chemical co-precipitation for preparation of magnetic nanoparticles. Initiation of high frequency electric discharge between coarse iron particles under a layer of distilled water allows obtaining pure magnetite nanoparticles.

  18. Magnetite Nanoparticles Prepared By Spark Erosion

    Science.gov (United States)

    Maiorov, M.; Blums, E.; Kronkalns, G.; Krumina, A.; Lubane, M.

    2016-08-01

    In the present research, we study a possibility of using the electric spark erosion method as an alternative to the method of chemical co-precipitation for preparation of magnetic nanoparticles. Initiation of high frequency electric discharge between coarse iron particles under a layer of distilled water allows obtaining pure magnetite nanoparticles.

  19. Magnetite Nanoparticles Prepared By Spark Erosion

    OpenAIRE

    Maiorov M.; Blums E.; Kronkalns G.; Krumina A.; Lubane M.

    2016-01-01

    In the present research, we study a possibility of using the electric spark erosion method as an alternative to the method of chemical co-precipitation for preparation of magnetic nanoparticles. Initiation of high frequency electric discharge between coarse iron particles under a layer of distilled water allows obtaining pure magnetite nanoparticles.

  20. Ambient fields generated by a laser spark

    Czech Academy of Sciences Publication Activity Database

    Rohlena, Karel; Mašek, Martin

    2016-01-01

    Roč. 61, č. 2 (2016), s. 119-124 ISSN 0029-5922 R&D Projects: GA MŠk(CZ) LD14089; GA MŠk(CZ) LG13031 Institutional support: RVO:68378271 Keywords : laser spark * radiation chemistry * field generation Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.760, year: 2016

  1. Exhaust purification of DI spark ignition engines by means of barrier discharge. Final report; Abgasreinigung von DI-Ottomotoren durch Barrierenentladungen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Wolters, P.; Lepperhoff, G.; Baumgarten, H.; Scharr, D.; Neff, W.; Trompeter, F.J.; Seiwert, S.; Kamp, J.; Pochner, K.

    2000-07-01

    Dielectric barrier discharge offers the advantage to excite and dissociate molecules in the exhaust gas stream. Those dissociated and excited species are oxidizing or reducing harmful exhaust gas components. The advantage of a plasma chemical system in comparison to a catalytic converter is the instantaneous activity at ambient temperature from the turn key of the engine. The investigations presented here focus on the plasma chemical oxidation of hydrocarbons in the exhaust gas stream during cold start conditions. The article concerns the design and development of a plasma system in order to decrease the hydrocarbon emissions from engine start till catalyst light off. Vehicle results in the new European driving cycle show a hydrocarbon conversion of more than 43% in the first 11 seconds from engine start. In this period nearly all types of hydrocarbon were reduced. The exhaust back pressure of the sytem is comparable to the conventional muffler. Further system improvement can be achieved by an optimization of the disk electrode design. [German] Um die strengen zukuenftigen Schadstoffemissionsgrenzwerte von Ottomotoren in der EU oder den USA einhalten zu koennen, werden derzeit weltweit auch plasmachemische Methoden zur Abgasnachbehandlung in Betracht gezogen. Insbesondere nichtthermische Atmosphaerendruck-Gasentladungen, wie die Barrierenentladung, zeigen Chancen auf, die Betriebsbedingungen und Grenzen gegenwaertiger katalytischer Techniken zu erweitern. In diesem Vorhaben wurde die Barrierenentladung zur plasmachemischen Umsetzung von Schadstoffen im Abgas eines mager betriebenen Ottomotors im Serienautomobil untersucht, um das Potential zur Abgasreinigung zu bewerten und auszuweiten. (orig.)

  2. Resistance of a water spark.

    Energy Technology Data Exchange (ETDEWEB)

    Warne, Larry Kevin; Jorgenson, Roy Eberhardt; Lehr, Jane Marie

    2005-11-01

    The later time phase of electrical breakdown in water is investigated for the purpose of improving understanding of the discharge characteristics. One dimensional simulations in addition to a zero dimensional lumped model are used to study the spark discharge. The goal is to provide better electrical models for water switches used in the pulse compression section of pulsed power systems. It is found that temperatures in the discharge channel under representative drive conditions, and assuming small initial radii from earlier phases of development, reach levels that are as much as an order of magnitude larger than those used to model discharges in atmospheric gases. This increased temperature coupled with a more rapidly rising conductivity with temperature than in air result in a decreased resistance characteristic compared to preceding models. A simple modification is proposed for the existing model to enable the approximate calculation of channel temperature and incorporate the resulting conductivity increase into the electrical circuit for the discharge channel. Comparisons are made between the theoretical predictions and recent experiments at Sandia. Although present and past experiments indicated that preceding late time channel models overestimated channel resistance, the calculations in this report seem to underestimate the resistance relative to recent experiments. Some possible reasons for this discrepancy are discussed.

  3. Laser-induced breakdown spectroscopy with multi-kHz fibre laser for mobile metal analysis tasks — A comparison of different analysis methods and with a mobile spark-discharge optical emission spectroscopy apparatus

    International Nuclear Information System (INIS)

    Scharun, Michael; Fricke-Begemann, Cord; Noll, Reinhard

    2013-01-01

    The identification and separation of different alloys are a permanent task of crucial importance in the metal recycling industry. Laser-induced breakdown spectroscopy (LIBS) offers important advantages in comparison to the state-of-the-art techniques for this application. For LIBS measurement no additional sample preparation is necessary. The overall analysis time is much smaller than for the state-of-the-art techniques. The LIBS setup presented in this study enables mobile operation with a handheld probe for the analysis of metallic materials. Excitation source is a fibre laser with a repetition rate of 30 kHz and a pulse energy of 1.33 mJ. The compact optical setup allows measurements at almost every point of a sample within 5 ms. The generated plasma light is analysed using a Multi-CCD spectrometer. The broad spectral coverage and high resolution provide an outstanding amount of spectroscopic information thereby enabling a variety of calibration approaches. Using a set of Al-based and a set of Fe-based samples the analytical performance of uni- and multivariate calibrations is evaluated. The same sample sets are analysed with a commercial state-of-the-art spark-discharge optical emission spectrometer allowing an assessment of the achieved results. Even though the possible analytical correctness of the fibre laser based LIBS measurements is found to similar or even better than that of the conventional technique, advantages of the multivariate data evaluation have not yet been realised in the investigations. However, due to the in situ sample preparation and short measurement times, fibre-laser based LIBS offers superior features. - Highlights: • Mobile, hand-guided LIBS apparatus for metal analysis, even for steel • Comparable results as state-of-the-art SD-OES instrument • New sectioned calibration function resulting in smaller deviations • Comparison of univariate and multivariate analysis methods

  4. Optical spark chamber

    CERN Multimedia

    CERN PhotoLab

    1971-01-01

    An optical spark chamber developed for use in the Omega spectrometer. On the left the supporting frame is exceptionally thin to allow low momentum particles to escape and be detected outside the magnetic field.

  5. Characteristics of a miniature vacuum spark

    Science.gov (United States)

    Wong, C. S.; Ong, C. X.; Chin, O. H.; Lee, S.; Choi, P.

    1989-12-01

    The characteristics of a miniature vacuum spark device are investigated. It is powered by a 2-stage 50 kV Marx and operated without an external triggering source. Discharge initiation is effected by an electron beam produced by the Pseudospark effect behind the hollow cathode. For discharges performed in air at a pressure of below 10-2 mbar, intense X-ray is detected. Although this X-ray has been found to consist of predominantly the Fe-Kα line produced by the electron beam bombardment of the stainless steel anode, its high intensity, singly-pulsed short-duration temporal structure and nearly monochromatic spectrum make the present vacuum spark an ideal pulsed X-ray source for many applications. The device is also compact, low cost and easy to operate. As an example of its applications, the contact radiography of a living lizard has been obtained using this X-ray source.

  6. SparkRS - Spark for Remote Sensing, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is Spark-RS, an open source software project that enables GPU-accelerated remote sensing workflows in an Apache Spark distributed computing...

  7. SI Engine with repetitive NS spark plug

    Science.gov (United States)

    Pancheshniy, Sergey; Nikipelov, Andrey; Anokhin, Eugeny; Starikovskiy, Andrey; Laplase Team; Mipt Team; Pu Team

    2013-09-01

    Now de-facto the only technology for fuel-air mixtures ignition in IC engines exists. It is a spark discharge of millisecond duration in a short discharge gap. The reason for such a small variety of methods of ignition initiation is very specific conditions of the engine operation. First, it is very high-pressure of fuel-air mixture - from 5-7 atmospheres in old-type engines and up to 40-50 atmospheres on the operating mode of HCCI. Second, it is a very wide range of variation of the oxidizer/fuel ratio in the mixture - from almost stoichiometric (0.8-0.9) at full load to very lean (φ = 0.3-0.5) mixtures at idle and/or economical cruising mode. Third, the high velocity of the gas in the combustion chamber (up to 30-50 m/s) resulting in a rapid compression of swirling inlet flow. The paper presents the results of tests of distributed spark ignition system powered by repetitive pulse nanosecond discharge. Dynamic pressure measurements show the increased pressure and frequency stability for nanosecond excitation in comparison with the standard spark plug. Excitation by single nanosecond high-voltage pulse and short train of pulses was examined. In all regimes the nanosecond pulsed excitation demonstrate a better performance.

  8. Testing of the J-2X Augmented Spark Igniter (ASI) and Its Electronics

    Science.gov (United States)

    Osborne, Robin

    2015-01-01

    Reliable operation of the spark ignition system electronics in the J-2X Augmented Spark Igniter (ASI) is imperative in assuring ASI ignition and subsequent Main Combustion Chamber (MCC) ignition events are reliable in the J-2X Engine. Similar to the man-rated J-2 and RS-25 engines, the J-2X ignition system electronics are equipped with spark monitor outputs intended to indicate that the spark igniters are properly energized and sparking. To better understand anomalous spark monitor data collected on the J-2X development engines at NASA Stennis Space Center (SSC), a comprehensive subsystem study of the engine's low- and high-tension spark ignition system electronics was conducted at NASA Marshall Space Flight Center (MSFC). Spark monitor output data were compared to more detailed spark diagnostics to determine if the spark monitor was an accurate indication of actual sparking events. In addition, ignition system electronics data were closely scrutinized for any indication of an electrical discharge in some location other than the firing tip of the spark igniter - a problem not uncommon in the development of high voltage ignition systems.

  9. Fast data processing with Spark

    CERN Document Server

    Sankar, Krishna

    2015-01-01

    Fast Data Processing with Spark - Second Edition is for software developers who want to learn how to write distributed programs with Spark. It will help developers who have had problems that were too big to be dealt with on a single computer. No previous experience with distributed programming is necessary. This book assumes knowledge of either Java, Scala, or Python.

  10. Primary Science Interview: Science Sparks

    Science.gov (United States)

    Bianchi, Lynne

    2016-01-01

    In this "Primary Science" interview, Lynne Bianchi talks with Emma Vanstone about "Science Sparks," which is a website full of creative, fun, and exciting science activity ideas for children of primary-school age. "Science Sparks" started with the aim of inspiring more parents to do science at home with their…

  11. Spark channel characteristics of a large Van de Graaff generator

    Science.gov (United States)

    Staniforth, J. A.; Charlesworth, T. R.

    1981-09-01

    The current in a spark channel following voltage breakdown between the high voltage terminal and pressure vessel wall of a large single-ended Van de Graaff machine has been measured. The current waveform is oscillatory and has an envelope which is damped with time. The observed damping coefficient is compared with that obtained using a theoretical expression for the variation of the spark channel resistance with time. Reasonable agreement has been achieved. It is also shown that the initial stored energy on the terminal is rapidly absorbed by the insulating gas during discharge.

  12. Shock-wave dynamics under expansion of the spark channel in gas

    CERN Document Server

    Korytchenko, K V; Chumakov, V I

    2001-01-01

    The process of formation of shock waves arising at a spark discharge is considered. According to analysis of experimental statistics the results of the various about dynamics of development of the spark channel are exposed to a doubt. The definition of a concept of time of formation of a shock wave is offered and its quantitative evaluation is carried out. It has allowed to distinguish the process of formation from the process of development of a shock wave,and also to explain the fact of formation of several shock waves at a spark discharge. The offered work can be put in a basis of a technique for evaluation of the intensity of a shock wave formed at a spark discharge.

  13. Sparking protection for MFTF-B neutral beam power supplies

    International Nuclear Information System (INIS)

    Cummings, D.B.

    1983-01-01

    This paper describes the upgrade of MFTF-B Neutral Beam Power Supplies for sparking protection. High performance ion sources spark repeatedly so ion source power supplies must be insensitive to sparking. The hot deck houses the series tetrode, arc and filament supplies, and controls. Hot deck shielding has been upgraded and a continuous shield around the arc, filament, gradient grid, and control cables now extends from the hot deck, through the core snubber, to the source. The shield carries accelerating current and connects only to the source. Shielded source cables go through an outer duct which now connects to a ground plane under the hot deck. This hybrid transmission line is a low inductance path for sparks discharging the stray capacitance of the hot deck and isolation transformers, reducing coupling to building steel. Parallel dc current return cables inside the duct lower inductance to reduce inductive turn-off transients. MOVs to ground further limit surges in the remote power supply return. Single point grounding is at the source. No control or rectifier components have been damaged nor are there any known malfunctions due to sparking up to 80 kV output

  14. Sliding-spark spectrometry of sediment samples.

    Science.gov (United States)

    Angeyo, H; Flórían, K; Golloch, A; Vojtekovà, V

    2002-10-01

    Direct analysis of non-conducting solids and dielectric surface layers for elements at trace levels has been shown to be feasible by the new so-called sliding-spark spectroscopy, in which a discharge plasma is bound by, and propagates on, the surface of a dielectric sample matrix. By using a river sediment as a model matrix, bound in PVC to improve elemental atomization and excitation efficiency, as a result of the formation of volatile chlorides, the potential of the technique for environmental applications has been investigated by studying the characteristic UV-visible radiation emitted in the wavelength range 210-510 nm for the elements Fe, Cr, Ni, Cu, Pb, Cd, Zn, Co, V, Ti, and Mn. The radiation was detected by means of a CCD spectrometer and analysed for spectral line identification, selection, and the linearity of the spectral response, to determine whether this was suitable for establishing a calibration strategy for quantitative analysis using the sliding-spark source.

  15. Are Crab nanoshots Schwinger sparks?

    Energy Technology Data Exchange (ETDEWEB)

    Stebbins, Albert [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Yoo, Hojin [Univ. of Wisconsin, Madison, WI (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)

    2015-05-21

    The highest brightness temperature ever observed are from "nanoshots" from the Crab pulsar which we argue could be the signature of bursts of vacuum e± pair production. If so this would be the first time the astronomical Schwinger effect has been observed. These "Schwinger sparks" would be an intermittent but extremely powerful, ~103 L, 10 PeV e± accelerator in the heart of the Crab. These nanosecond duration sparks are generated in a volume less than 1 m3 and the existence of such sparks has implications for the small scale structure of the magnetic field of young pulsars such as the Crab. As a result, this mechanism may also play a role in producing other enigmatic bright short radio transients such as fast radio bursts.

  16. Bright Sparks of Our Future!

    Science.gov (United States)

    Riordan, Naoimh

    2016-04-01

    My name is Naoimh Riordan and I am the Vice Principal of Rockboro Primary School in Cork City, South of Ireland. I am a full time class primary teacher and I teach 4th class, my students are aged between 9-10 years. My passion for education has developed over the years and grown towards STEM (Science, Technology, Engineering and Mathematics) subjects. I believe these subjects are the way forward for our future. My passion and beliefs are driven by the unique after school programme that I have developed. It is titled "Sparks" coming from the term Bright Sparks. "Sparks" is an after school programme with a difference where the STEM subjects are concentrated on through lessons such as Science, Veterinary Science Computer Animation /Coding, Eco engineering, Robotics, Magical Maths, Chess and Creative Writing. All these subjects are taught through activity based learning and are one-hour long each week for a ten-week term. "Sparks" is fully inclusive and non-selective which gives all students of any level of ability an opportunity to engage into these subjects. "Sparks" is open to all primary students in County Cork. The "Sparks" after school programme is taught by tutors from the different Universities and Colleges in Cork City. It works very well because the tutor brings their knowledge, skills and specialised equipment from their respective universities and in turn the tutor gains invaluable teaching practise, can trial a pilot programme in a chosen STEM subject and gain an insight into what works in the physical classroom.

  17. MV controlled spark gap

    International Nuclear Information System (INIS)

    Evdokimovich, V.M.; Evlampiev, S.B.; Korshunov, G.S.; Nikolaev, V.A.; Sviridov, Yu.F.; Khmyrov, V.V.

    1980-01-01

    A megavolt gas-filled trigatron gap with a sectional gas-discharge chamber having a more than three-fold range of operating voltages is described. The discharge chamber consists of ten sections, each 70 mm thick, made of organic glass. The sections are separated one from another by aluminium gradient rings to which ohmic voltage divider is connected. Insulational sections and gradient rings are braced between themselves by means of metal flanges through gaskets made of oil-resistant rubber with the help of fiberglass-laminate pins. The gap has two electrodes 110 mm in diameter. The trigatron ignition assembly uses a dielectric bushing projecting over the main electrode plane. Use has been made of a gas mixture containing 10% of SF 6 and 90% of air making possible to ensure stable gap operation without readjusting in the voltage range from 0.4 to 1.35 MV. The operation time lag in this range is equal to 10 μs at a spread of [ru

  18. Fiber coupled optical spark delivery system

    Science.gov (United States)

    Yalin, Azer; Willson, Bryan; Defoort, Morgan

    2008-08-12

    A spark delivery system for generating a spark using a laser beam is provided, the spark delivery system including a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. In addition, the laser delivery assembly includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. In accordance with embodiments of the present invention, the assembly may be used to create a spark in a combustion engine. In accordance with other embodiments of the present invention, a method of using the spark delivery system is provided. In addition, a method of choosing an appropriate fiber for creating a spark using a laser beam is also presented.

  19. Spark-erosion characteristics of graphite and CO gas

    International Nuclear Information System (INIS)

    Bickford, K.J.; Hanks, K.W.; Willis, W.L.

    1982-01-01

    The spark erosion characteristic of high-purity graphite and CO for 1-kHz gas blown rail-gap applications has been experimentally evaluated. The test configuration simulates a single channel, 1650-A arc discharge per linear inch of electrode length, with a 44-kV self-breakdown voltage and a transverse gas flow of 98 m/s. The dielectric gas was seeded with a small quantity of azulene vapor and a downstream uv preionization spark was used to assist the self-breakdown of the test electrodes. The erosion characteristics of other, more conventional electrode materials and dielectric gases were also examined and the results are presented graphically. Commerically pure tungsten in air was determined to exhibit the least erosion rate (2.1 x 10 -6 cc/C) for this duty, as compared to graphite and CO

  20. Capacitor Discharge - A Capacitor Tutorial [video

    OpenAIRE

    Naval Postgraduate School Physics

    2014-01-01

    NPS Physics Physics Demonstrations Here's a capacitor discharge demonstrated by physicist Dr. Dernardo. Dr. D gives a nice capacitor lesson along with some fireworks. Charging and Discharging a Capacitor is dangerous. Do not try this at home. Dr. Bruce Denardo uses eleven 9V batteries, connected in series for a total of 99 creating a pretty large spark.

  1. Overvoltage protection by point-plane spark gaps

    International Nuclear Information System (INIS)

    Scarlett, W.R.; Riepe, K.B.

    1979-01-01

    In electron-beam-controlled discharge CO 2 lasers, such as those used in the Antares and Helios laser-fusion drivers at the Los Alamos Scientific Laboratory (LASL), protection needs to be provided against possible damage due to overvoltage. A passive (self-breakdown) point-plane spark gap has been developed and successfully used in the Helios power amplifiers which operate at voltages up to 300 kV. A gap of similar design is planned for use in the Antares power amplifiers which operate at 550 kV. These gaps must reliably hold off the normal discharge voltage, but break down with short delay if overvoltaged, diverting the discharge energy to a resistor. A prototype of the Antares gap has been built and is undergoing tests. Parameters being investigated include voltage polarity, gap spacing, gas composition, and gas pressure. Results of these measurements and the operational experience of the Helios gaps will be presented

  2. X-ray Production in Laboratory Sparks in air

    Science.gov (United States)

    Rahman, M.; Cooray, G. V.; Rakov, V. A.

    2007-12-01

    Dwyer et al. [2005] recently observed X-ray bursts (in the 30 to 150 keV range) from high-voltage laboratory sparks (positive and negative; 5 cm - 2 m) in air. In this paper, we present results of an independent experiment conducted at a different high-voltage facility and using different instrumentation to confirm (or refute) the production of X-rays by laboratory discharges. The experiment was conducted at the high-voltage laboratory of Uppsala University, Sweden. A spark was created in air at atmospheric pressure applying a standard lightning impulse voltage (1.2/50 impulse; front time: 1.2 μs, time to half-value: 50 μs) to an 80-cm long rod-to-hemisphere air gap. In this experiment the generator was charged to 1 MV with negative polarity. The voltage across the gap at breakdown, the current in the spark, the visible optical radiation from the spark, and the emission of X-rays produced by the spark were measured. The emission of X-rays was detected by a barium fluoride (BaF2) crystal scintillator which had a shape of frustum of a right cone (front diameter: 2.2 cm, rear diameter: 4 cm, and length: 4 cm). The scintillator was attached to a 51 mm PMT (Photonis XP2020/URQ, rise time 1.4 ns, spectral sensitivity 200-550 nm). The ungrounded, light-tight, and electromagnetically sealed metal cabinet having the complete X-ray detector, optical measuring system, oscilloscope and power supplies, was placed about 1 m away from the spark gap so that the center of the crystal was a few centimetres below the high voltage rod electrode. A total of 83 negative voltage impulses were applied across the gap and in 49 cases (59% of the events) the X-ray signals were detected. In 23 cases, the X-ray signal appeared before the collapse of the applied voltage across the gap and about 1 μs prior to onset of the main discharge current. In 26 cases, the X-ray signal appeared at around the main discharge current peak. A rough estimation of total deposited energy in the crystal was

  3. Observation of a spark channel generated in water with shock wave assistance in plate-to-plate electrode configuration

    Czech Academy of Sciences Publication Activity Database

    Stelmashuk, Vitaliy

    2014-01-01

    Roč. 21, č. 1 (2014), 010703/1-010703/3 ISSN 1070-664X Institutional support: RVO:61389021 Keywords : discharge * spark * plasma instability Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.142, year: 2014 http://scitation.aip.org/content/aip/journal/pop/21/1/10.1063/1.4861877

  4. Reduction to spark coordinates of data generated by automatic measurement of spark chamber film

    International Nuclear Information System (INIS)

    Maybury, R.; Hart, J.C.

    1976-09-01

    The initial stage in the data reduction for film from two spark chamber experiments is described. The film was automatically measured at the Rutherford Laboratory. The data from these measurements were reduced to a series of spark coordinates for each gap of the spark chambers. Quality control checks are discussed. (author)

  5. Spark Discharge Generated Nanoparticles for Hydrogen Storage Applications

    NARCIS (Netherlands)

    Vons, V.A.

    2010-01-01

    One of the largest obstacles to the large scale application of hydrogen powered fuel cell vehicles is the absence of hydrogen storage methods suitable for application on-board of these vehicles. Metal hydrides are materials in which hydrogen is reversibly absorbed by one or more metals or

  6. Towards the Industrial Application of Spark Ablation for Nanostructured Functional Materials

    NARCIS (Netherlands)

    Pfeiffer, T.V.

    2014-01-01

    Nanostructuring of functional materials is an essential part in the design of energy related devices – but the industrial tools we have to make these materials are lacking. This dissertation explores the green, flexible, and scalable spark discharge process for the fabrication of complex

  7. A compact spark pre-ionized pulser sustainer TE–CO2 laser

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Abstract. A compact spark pre-ionized pulser sustainer TE–CO2 laser that can produce an output energy of one joule with an overall efficiency of 12·4% is presented. Optical pulses have durations of 7·15µs FWHM. Here, the laser uses all solid-state excitation (ASSE) circuit and the discharge formed between two.

  8. Arc Current, Voltage, and Resistance in a High Energy, Gas Filled Spark Gap

    Science.gov (United States)

    1985-06-01

    Rompe [8] show discrepancies of up to a factor of 10, excellent agreement is found with the model of Mesyats [ 6] and Vlastos [9] for times up to...Leipzig Johann Ambrosius [9] Vlastos , A.E. "The Channel Resistance of Sparks," lEE Gas Discharges Conference Proceedings, pp. 31- 34 (Sept. 1970

  9. Development of Augmented Spark Impinging Igniter System for Methane Engines

    Science.gov (United States)

    Marshall, William M.; Osborne, Robin J.; Greene, Sandra E.

    2017-01-01

    The Lunar Cargo Transportation and Landing by Soft Touchdown (Lunar CATALYST) program is establishing multiple no-funds-exchanged Space Act Agreement (SAA) partnerships with U.S. private sector entities. The purpose of this program is to encourage the development of robotic lunar landers that can be integrated with U.S. commercial launch capabilities to deliver payloads to the lunar surface. As part of the efforts in Lander Technologies, NASA Marshall Space Flight Center (MSFC) is developing liquid oxygen (LOX) and liquid methane (LCH4) engine technology to share with the Lunar CATALYST partners. Liquid oxygen and liquid methane propellants are attractive owing to their relatively high specific impulse for chemical propulsion systems, modest storage requirements, and adaptability to NASA's Journey to Mars plans. Methane has also been viewed as a possible propellant choice for lunar missions, owing to the performance benefits and as a technology development stepping stone to Martian missions. However, in the development of methane propulsion, methane ignition has historically been viewed as a high risk area in the development of such an engine. A great deal of work has been conducted in the past decade devoted to risk reduction in LOX/CH4 ignition. This paper will review and summarize the history and results of LOX/CH4 ignition programs conducted at NASA. More recently, a NASA-developed Augmented Spark Impinging (ASI) igniter body, which utilizes a conventional spark exciter system, is being tested with LOX/CH4 to help support internal and commercial engine development programs, such as those in Lunar CATALYST. One challenge with spark exciter systems, especially at altitude conditions, is the ignition lead that transmits the high voltage pulse from the exciter to the spark igniter (spark plug). The ignition lead can be prone to corona discharge, reducing the energy delivered by the spark and potentially causing non-ignition events. For the current work, a

  10. SparkJet characterizations in quiescent and supersonic flowfields

    Science.gov (United States)

    Emerick, T.; Ali, M. Y.; Foster, C.; Alvi, F. S.; Popkin, S.

    2014-12-01

    The aerodynamic community has studied active flow control actuators for some time, and developments have led to a wide variety of devices with various features and operating mechanisms. The design requirements for a practical actuator used for active flow control include reliable operation, requisite frequency and amplitude modulation capabilities, and a reasonable lifespan while maintaining minimal cost and design complexity. An active flow control device called the SparkJet actuator has been developed for high-speed flight control and incorporates no mechanical/moving parts, zero net mass flux capabilities and the ability to tune the operating frequency and momentum throughput. This actuator utilizes electrical power to deliver high-momentum flow with a very fast response time. The SparkJet actuator was characterized on the benchtop using a laser-based microschlieren visualization technique and maximum blast wave and jet front velocities of ~400 and ~310 m/s were, respectively, measured in the flowfield. An increase in jet front velocity from 240 to 310 m/s during subatmospheric (60 kPa) testing reveals that the actuator may have greater control authority at lower ambient pressures, which correspond to high-altitude flight conditions for air vehicles. A SparkJet array was integrated into a flat plate and tested in a Mach 1.5 crossflow. Phase-conditioned shadowgraph results revealed a maximum flow deflection angle of 5° created by the SparkJet 275 µs after the actuator was triggered in single-shot mode. Burst mode operation of frequencies up to 700 Hz revealed similar results during wind tunnel testing. Following these tests, the actuator trigger mechanism was improved and the ability of the actuator to be discharged in burst mode at a frequency of 1 kHz was achieved.

  11. Review of the Soft Sparking Issues in Plasma Electrolytic Oxidation

    Directory of Open Access Journals (Sweden)

    Dah-Shyang Tsai

    2018-02-01

    Full Text Available A dense inner layer is highly valued among the surface coatings created through plasma electrolytic oxidation (PEO treatment, because the PEO coating has been troubled by inherent porosity since its conception. To produce the favored structure, a proven technique is to prompt a soft sparking transition, which involves a sudden decrease in light and acoustic emissions, and a drop in anodic voltage under controlled current mode. Typically these phenomena occur in an electrolyte of sodium silicate and potassium hydroxide, when an Al-based sample is oxidized with an AC or DC (alternating or direct current pulse current preset with the cathodic current exceeding the anodic counterpart. The dense inner layer feature is pronounced if a sufficient amount of oxide has been amassed on the surface before the transition begins. Tremendous efforts have been devoted to understand soft sparking at the metal–oxide–electrolyte interface. Studies on aluminum alloys reveal that the dense inner layer requires plasma softening to avoid discharge damages while maintaining a sufficient growth rate, a porous top layer to retain heat for sintering the amassed oxide, and proper timing to initiate the transition and end the surface processing after transition. Despite our understanding, efforts to replicate this structural feature in Mg- and Ti-based alloys have not been very successful. The soft sparking phenomena can be reproduced, but the acquired structures are inferior to those on aluminum alloys. An analogous quality of the dense inner layer is only achieved on Mg- and Ti-based alloys with aluminate anion in the electrolytic solution and a suitable cathodic current. These facts point out that the current soft sparking knowledge on Mg- and Ti-based alloys is insufficient. The superior inner layer on the two alloys still relies on rectification and densification of aluminum oxide.

  12. Numerical simulation of spark ignition including ionization

    NARCIS (Netherlands)

    Thiele, M; Selle, S; Riedel, U; Warnatz, J; Maas, U

    2000-01-01

    A detailed understanding of the processes associated Midi spark ignition, as a first step during combustion, is of great importance fur clean operation of spark ignition engines. In the past 10 years. a growing concern for environmental protection, including low emission of pollutants, has increased

  13. Simulation of nonstationary phenomena in atmospheric-pressure glow discharge

    International Nuclear Information System (INIS)

    Korolev, Yu. D.; Frants, O. B.; Nekhoroshev, V. O.; Suslov, A. I.; Kas’yanov, V. S.; Shemyakin, I. A.; Bolotov, A. V.

    2016-01-01

    Nonstationary processes in atmospheric-pressure glow discharge manifest themselves in spontaneous transitions from the normal glow discharge into a spark. In the experiments, both so-called completed transitions in which a highly conductive constricted channel arises and incomplete transitions accompanied by the formation of a diffuse channel are observed. A model of the positive column of a discharge in air is elaborated that allows one to interpret specific features of the discharge both in the stationary stage and during its transition into a spark and makes it possible to calculate the characteristic oscillatory current waveforms for completed transitions into a spark and aperiodic ones for incomplete transitions. The calculated parameters of the positive column in the glow discharge mode agree well with experiment. Data on the densities of the most abundant species generated in the discharge (such as atomic oxygen, metastable nitrogen molecules, ozone, nitrogen oxides, and negative oxygen ions) are presented.

  14. Simulation of nonstationary phenomena in atmospheric-pressure glow discharge

    Science.gov (United States)

    Korolev, Yu. D.; Frants, O. B.; Nekhoroshev, V. O.; Suslov, A. I.; Kas'yanov, V. S.; Shemyakin, I. A.; Bolotov, A. V.

    2016-06-01

    Nonstationary processes in atmospheric-pressure glow discharge manifest themselves in spontaneous transitions from the normal glow discharge into a spark. In the experiments, both so-called completed transitions in which a highly conductive constricted channel arises and incomplete transitions accompanied by the formation of a diffuse channel are observed. A model of the positive column of a discharge in air is elaborated that allows one to interpret specific features of the discharge both in the stationary stage and during its transition into a spark and makes it possible to calculate the characteristic oscillatory current waveforms for completed transitions into a spark and aperiodic ones for incomplete transitions. The calculated parameters of the positive column in the glow discharge mode agree well with experiment. Data on the densities of the most abundant species generated in the discharge (such as atomic oxygen, metastable nitrogen molecules, ozone, nitrogen oxides, and negative oxygen ions) are presented.

  15. Spark gap produced plasma diagnostics

    International Nuclear Information System (INIS)

    Chang, H.Y.

    1990-01-01

    A Spark Gap (Applied voltage : 2-8KV, Capacitor : 4 Micro F. Dia of the tube : 1 inch, Electrode distance : .3 ∼.5 inch) was made to generate a small size dynamic plasma. To measure the plasma density and temperature as a function of time and position, we installed and have been installing four detection systems - Mach-Zehnder type Interferometer for the plasma refractivity, Expansion speed detector using two He-Ne laser beams, Image Processing using Lens and A Optical-Fiber Array for Pointwise Radiation Sensing, Faraday Rotation of a Optical Fiber to measure the azimuthal component of B-field generated by the plasma drift. These systems was used for the wire explosion diagnostics, and can be used for the Laser driven plasma also

  16. GeoSpark SQL: An Effective Framework Enabling Spatial Queries on Spark

    Directory of Open Access Journals (Sweden)

    Zhou Huang

    2017-09-01

    Full Text Available In the era of big data, Internet-based geospatial information services such as various LBS apps are deployed everywhere, followed by an increasing number of queries against the massive spatial data. As a result, the traditional relational spatial database (e.g., PostgreSQL with PostGIS and Oracle Spatial cannot adapt well to the needs of large-scale spatial query processing. Spark is an emerging outstanding distributed computing framework in the Hadoop ecosystem. This paper aims to address the increasingly large-scale spatial query-processing requirement in the era of big data, and proposes an effective framework GeoSpark SQL, which enables spatial queries on Spark. On the one hand, GeoSpark SQL provides a convenient SQL interface; on the other hand, GeoSpark SQL achieves both efficient storage management and high-performance parallel computing through integrating Hive and Spark. In this study, the following key issues are discussed and addressed: (1 storage management methods under the GeoSpark SQL framework, (2 the spatial operator implementation approach in the Spark environment, and (3 spatial query optimization methods under Spark. Experimental evaluation is also performed and the results show that GeoSpark SQL is able to achieve real-time query processing. It should be noted that Spark is not a panacea. It is observed that the traditional spatial database PostGIS/PostgreSQL performs better than GeoSpark SQL in some query scenarios, especially for the spatial queries with high selectivity, such as the point query and the window query. In general, GeoSpark SQL performs better when dealing with compute-intensive spatial queries such as the kNN query and the spatial join query.

  17. Bubbles, sparks, and the postwar laboratory

    International Nuclear Information System (INIS)

    Galison, P.

    1989-01-01

    The development and use of bubble chambers and spark chambers in the 1950s form the main thrust of this article, the bubble chamber as an example of ''image-producing'' instruments and the spark chamber as a ''logic'' device. Work on a cloud chamber by Glaser led to the development of the bubble chamber detector using liquid hydrogen, which was later linked to a computer for accurate automatic track analysis. It made possible demonstrations of the existence of a particle or interaction. Spark chambers were easier to build and so soon became common, various types being developed across the world. The development of spark chambers originated in the need for timing devices for the Manhattan Project, but work on their design occurred in a number of units worldwide. (UK)

  18. 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...

  19. Enhancement of flame development by microwave-assisted spark ignition in constant volume combustion chamber

    KAUST Repository

    Wolk, Benjamin

    2013-07-01

    The enhancement of laminar flame development using microwave-assisted spark ignition has been investigated for methane-air mixtures at a range of initial pressures and equivalence ratios in a 1.45. l constant volume combustion chamber. Microwave enhancement was evaluated on the basis of several parameters including flame development time (FDT) (time for 0-10% of total net heat release), flame rise time (FRT) (time for 10-90% of total net heat release), total net heat release, flame kernel growth rate, flame kernel size, and ignitability limit extension. Compared to a capacitive discharge spark, microwave-assisted spark ignition extended the lean and rich ignition limits at all pressures investigated (1.08-7.22. bar). The addition of microwaves to a capacitive discharge spark reduced FDT and increased the flame kernel size for all equivalence ratios tested and resulted in increases in the spatial flame speed for sufficiently lean flames. Flame enhancement is believed to be caused by (1) a non-thermal chemical kinetic enhancement from energy deposition to free electrons in the flame front and (2) induced flame wrinkling from excitation of flame (plasma) instability. The enhancement of flame development by microwaves diminishes as the initial pressure of the mixture increases, with negligible flame enhancement observed above 3. bar. © 2013 The Combustion Institute.

  20. Development of Augmented Spark Impinging Igniter System for Methane Engines

    Science.gov (United States)

    Marshall, William M.; Osborne, Robin J.; Greene, Sandra E.

    2017-01-01

    The Lunar Cargo Transportation and Landing by Soft Touchdown (Lunar CATALYST) program is establishing multiple no-funds-exchanged Space Act Agreement (SAA) partnerships with U.S. private sector entities. The purpose of this program is to encourage the development of robotic lunar landers that can be integrated with U.S. commercial launch capabilities to deliver payloads to the lunar surface. NASA can share technology and expertise under the SAA for the benefit of the CATALYST partners. MSFC seeking to vacuum test Augmented Spark Impinging (ASI) igniter with methane and new exciter units to support CATALYST partners and NASA programs. ASI has previously been used/tested successfully at sea-level, with both O2/CH4 and O2/H2 propellants. Conventional ignition exciter systems historically experienced corona discharge issues in vacuum. Often utilized purging or atmospheric sealing on high voltage lead to remedy. Compact systems developed since PCAD could eliminate the high-voltage lead and directly couple the exciter to the spark igniter. MSFC developed Augmented Spark Impinging (ASI) igniter. Successfully used in several sea-level test programs. Plasma-assisted design. Portion of ox flow is used to generate hot plasma. Impinging flows downstream of plasma. Additional fuel flow down torch tube sleeve for cooling near stoichiometric torch flame. Testing done at NASA GRC Altitude Combustion Stand (ACS) facility 2000-lbf class facility with altitude simulation up to around 100,000 ft. (0.2 psia [10 Torr]) via nitrogen driven ejectors. Propellant conditioning systems can provide temperature control of LOX/CH4 up to test article.

  1. Ultraviolet radiation induced discharge laser

    Science.gov (United States)

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

    1978-01-01

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

  2. Scattering profiles of sparks and combustibility of filter against hot sparks

    International Nuclear Information System (INIS)

    Asazuma, Shinichiro; Okada, Takashi; Kashiro, Kashio

    2004-01-01

    The glove-box dismantling facility in the Plutonium Fuel Production Facility is developed to dismantle after-service glove-boxes with remote-controlled devices such as an arm-type manipulator. An abrasive wheel cutter, which is used to size reduce the gloveboxes, generates sparks during operation. This dispersing spark was a problem from the fire prevention point of view. A suitable spark control measures for this operation were required. We developed panels to minimize spark dispersion, shields to prevent the income of sparks to the pre-filter, and incombustible pre-filters. The equipment was tested and effectiveness was confirmed. This report provides the results of these tests. (author)

  3. Heart pacemaker - discharge

    Science.gov (United States)

    Cardiac pacemaker implantation - discharge; Artificial pacemaker - discharge; Permanent pacemaker - discharge; Internal pacemaker - discharge; Cardiac resynchronization therapy - discharge; CRT - discharge; ...

  4. Gas spark switches with increased operating life for Marx generator of lightning test complex

    Science.gov (United States)

    Bykov, Yu. A.; Krastelev, E. G.

    2016-12-01

    A new design of gas spark switches with an increased operating life and stable dynamic characteristics for the Marx generator of the lightning test complex has been developed. The switches are characterized by the following parameters in the mode of operation: voltage up to 80 kV, discharge current up to 50 kA, flowing charge up to 3.5 C/pulse. An increased operating life is achieved by using torus-shaped electrodes with increased working surface area and a trigger electrode in the form of a thick disk with a hole located between them. Low breakdown delay time and high stability of breakdown voltage under dynamic conditions are provided by gas preionization in the spark gap using UV radiation of an additional corona discharge in the axial region.

  5. Gas spark switches with increased operating life for Marx generator of lightning test complex

    Energy Technology Data Exchange (ETDEWEB)

    Bykov, Yu. A.; Krastelev, E. G., E-mail: ekrastelev@yandex.ru [Russian Academy of Sciences, Joint Institute for High Temperature (Russian Federation)

    2016-12-15

    A new design of gas spark switches with an increased operating life and stable dynamic characteristics for the Marx generator of the lightning test complex has been developed. The switches are characterized by the following parameters in the mode of operation: voltage up to 80 kV, discharge current up to 50 kA, flowing charge up to 3.5 C/pulse. An increased operating life is achieved by using torus-shaped electrodes with increased working surface area and a trigger electrode in the form of a thick disk with a hole located between them. Low breakdown delay time and high stability of breakdown voltage under dynamic conditions are provided by gas preionization in the spark gap using UV radiation of an additional corona discharge in the axial region.

  6. Electromagnetic fields radiated from electrostatic discharges: Theory and experiment

    Science.gov (United States)

    Wilson, Perry F.; Ondrejka, Arthur R.; Ma, Mark T.; Ladbury, John M.

    1988-02-01

    The fields radiated by electrostatic discharges (ESD) are studied both theoretically and experimentally. The ESD spark is modeled theoretically as an electrically short, time dependent, linear dipole situated above an infinite ground plane. Experimentally, sparks of varying voltages are generated by a commercially available simulator and used to excite a number of targets including: (1) the extended inner conductor of a coaxial cable mounted in a ground plane, (2) direct discharges to a ground plane, (3) indirect radiation from a large metal plate, (4) a metal chair over a a ground plane, and (5) a metal trash can. Results show that relatively low-voltage sparks (2 to 4 kV) excite the strongest radiated fields. This suggests that the spark fields can pose a significant interference threat to electronic equipment into the gigahertz range.

  7. Laser spark distribution and ignition system

    Science.gov (United States)

    Woodruff, Steven [Morgantown, WV; McIntyre, Dustin L [Morgantown, WV

    2008-09-02

    A laser spark distribution and ignition system that reduces the high power optical requirements for use in a laser ignition and distribution system allowing for the use of optical fibers for delivering the low peak energy pumping pulses to a laser amplifier or laser oscillator. An optical distributor distributes and delivers optical pumping energy from an optical pumping source to multiple combustion chambers incorporating laser oscillators or laser amplifiers for inducing a laser spark within a combustion chamber. The optical distributor preferably includes a single rotating mirror or lens which deflects the optical pumping energy from the axis of rotation and into a plurality of distinct optical fibers each connected to a respective laser media or amplifier coupled to an associated combustion chamber. The laser spark generators preferably produce a high peak power laser spark, from a single low power pulse. The laser spark distribution and ignition system has application in natural gas fueled reciprocating engines, turbine combustors, explosives and laser induced breakdown spectroscopy diagnostic sensors.

  8. Modeling and evaluation of the influence of micro-EDM sparking state settings on the tool electrode wear behavior

    DEFF Research Database (Denmark)

    Puthumana, Govindan

    2017-01-01

    materials characterized by considerable wear ofthe tool used for material removal. This paper presents an investigation involving modeling and estimation of the effect of settings for generation of discharges in stable conditions of micro-EDM on the phenomenon of tool electrode wear. A stable sparking...... a condition for the minimum tool wear for this micro-EDM process configuration....

  9. Using SPARK as a Solver for Modelica

    Energy Technology Data Exchange (ETDEWEB)

    Wetter, Michael; Wetter, Michael; Haves, Philip; Moshier, Michael A.; Sowell, Edward F.

    2008-06-30

    Modelica is an object-oriented acausal modeling language that is well positioned to become a de-facto standard for expressing models of complex physical systems. To simulate a model expressed in Modelica, it needs to be translated into executable code. For generating run-time efficient code, such a translation needs to employ algebraic formula manipulations. As the SPARK solver has been shown to be competitive for generating such code but currently cannot be used with the Modelica language, we report in this paper how SPARK's symbolic and numerical algorithms can be implemented in OpenModelica, an open-source implementation of a Modelica modeling and simulation environment. We also report benchmark results that show that for our air flow network simulation benchmark, the SPARK solver is competitive with Dymola, which is believed to provide the best solver for Modelica.

  10. Spark - a modern approach for distributed analytics

    CERN Multimedia

    CERN. Geneva; Kothuri, Prasanth

    2016-01-01

    The Hadoop ecosystem is the leading opensource platform for distributed storing and processing big data. It is a very popular system for implementing data warehouses and data lakes. Spark has also emerged to be one of the leading engines for data analytics. The Hadoop platform is available at CERN as a central service provided by the IT department. By attending the session, a participant will acquire knowledge of the essential concepts need to benefit from the parallel data processing offered by Spark framework. The session is structured around practical examples and tutorials. Main topics: Architecture overview - work distribution, concepts of a worker and a driver Computing concepts of transformations and actions Data processing APIs - RDD, DataFrame, and SparkSQL

  11. High performance Spark best practices for scaling and optimizing Apache Spark

    CERN Document Server

    Karau, Holden

    2017-01-01

    Apache Spark is amazing when everything clicks. But if you haven’t seen the performance improvements you expected, or still don’t feel confident enough to use Spark in production, this practical book is for you. Authors Holden Karau and Rachel Warren demonstrate performance optimizations to help your Spark queries run faster and handle larger data sizes, while using fewer resources. Ideal for software engineers, data engineers, developers, and system administrators working with large-scale data applications, this book describes techniques that can reduce data infrastructure costs and developer hours. Not only will you gain a more comprehensive understanding of Spark, you’ll also learn how to make it sing. With this book, you’ll explore: How Spark SQL’s new interfaces improve performance over SQL’s RDD data structure The choice between data joins in Core Spark and Spark SQL Techniques for getting the most out of standard RDD transformations How to work around performance issues i...

  12. Chaotic combustion in spark ignition engines

    International Nuclear Information System (INIS)

    Wendeker, Miroslaw; Czarnigowski, Jacek; Litak, Grzegorz; Szabelski, Kazimierz

    2003-01-01

    We analyse the combustion process in a spark ignition engine using the experimental data of an internal pressure during the combustion process and show that the system can be driven to chaotic behaviour. Our conclusion is based on the observation of unperiodicity in the time series, suitable stroboscopic maps and a complex structure of a reconstructed strange attractor. This analysis can explain that in some circumstances the level of noise in spark ignition engines increases considerably due to nonlinear dynamics of a combustion process

  13. The suppression of destructive sparks in parallel plate proportional counters

    Energy Technology Data Exchange (ETDEWEB)

    Cockshott, R.A.; Mason, I.M.

    1984-02-01

    The authors find that high energy background events produce localised sparks in parallel plate counters when operated in the proportional mode. These sparks increase dead-time and lead to degradation ranging from electrode damage to spurious pulsing and continuous breakdown. The problem is particularly serious in low energy photon detectors for X-ray astronomy which are required to have lifetimes of several years in the high radiation environment of space. For the parallel plate imaging detector developed for the European X-ray Observatory Satellite (EXOSAT) they investigate quantitatively the spark thresholds, spark rates and degradation processes. They discuss the spark mechanism, pointing out differences from the situation in spark chambers and counters. They show that the time profile of the sparks allows them to devise a spark suppression system which reduces the degradation rate by a factor of ''200.

  14. Modelling Spark Integration in Science Classroom

    Directory of Open Access Journals (Sweden)

    Marie Paz E. Morales

    2014-02-01

    Full Text Available The study critically explored how a PASCO-designed technology (SPARK ScienceLearning System is meaningfully integrated into the teaching of selected topics in Earth and Environmental Science. It highlights on modelling the effectiveness of using the SPARK Learning System as a primary tool in learning science that leads to learning and achievement of the students. Data and observation gathered and correlation of the ability of the technology to develop high intrinsic motivation to student achievement were used to design framework on how to meaningfully integrate SPARK ScienceLearning System in teaching Earth and Environmental Science. Research instruments used in this study were adopted from standardized questionnaires available from literature. Achievement test and evaluation form were developed and validated for the purpose of deducing data needed for the study. Interviews were done to delve into the deeper thoughts and emotions of the respondents. Data from the interviews served to validate all numerical data culled from this study. Cross-case analysis of the data was done to reveal some recurring themes, problems and benefits derived by the students in using the SPARK Science Learning System to further establish its effectiveness in the curriculum as a forerunner to the shift towards the 21st Century Learning.

  15. SparkJet Actuators for Flow Control

    Science.gov (United States)

    2007-03-01

    characteristics 5. Computational Predictions Both 2D and 3D time-dependent Navier -Stokes calculations of the SparkJet operation have been conducted using the...single sheet of stainless steel shim stock . This metal structure is oriented vertically and clamped at the top and bottom in a Lexan® fixture. The

  16. Book Review of Nicholas Sparks' Safe Haven

    OpenAIRE

    Putriyani, Maygananda

    2015-01-01

    Safe Haven (2010) is a novel written by Nicholas Sparks. It is a story about a woman who suffers from traumatic experience due to her abusive husband. She manages to escape to a safe place and find happiness in that place. The woman wants to start a new life even though the shadow of the past will always haunt her.

  17. Origin and simulation of sparks in MPGD

    CERN Document Server

    Procureur, S; Ball, J; Charles, G; Moreno, B; Moutarde, H; Sabatié, F

    2012-01-01

    The development of Micro-Pattern Gaseous Detectors for high luminosity experiments requires a better understanding of the origin of the sparks in these detectors. Assuming a spark occurs whenever the electron number reaches the well known Raether limit, previous Geant4 simulations quantitatively reproduced the spark rate observed in Micromegas with high energy hadron beams. Large release of energies are provided by fragments from nuclear interactions between the beam and the detector material. In order to further check the validity of our simulation, hadron beam tests have been performed at the CERN/SPS and PS on Micromegas and hybrid Micromegas-GEM detectors. In particular, large variations of the spark rate have been observed in positively charged hadron beams below 1 GeV/c, which are well described by the simulation. The role of the charge density has also been investigated with measurements in magnetic fields and with a Micromegas-GEM. The simulation has therefore been upgraded to take into account the tr...

  18. Efficiency calibration of solid track spark auto counter

    International Nuclear Information System (INIS)

    Wang Mei; Wen Zhongwei; Lin Jufang; Liu Rong; Jiang Li; Lu Xinxin; Zhu Tonghua

    2008-01-01

    The factors influencing detection efficiency of solid track spark auto counter were analyzed, and the best etch condition and parameters of charge were also reconfirmed. With small plate fission ionization chamber, the efficiency of solid track spark auto counter at various experiment assemblies was re-calibrated. The efficiency of solid track spark auto counter at various experimental conditions was obtained. (authors)

  19. System for time-discretized vacuum ultraviolet spectroscopy of spark breakdown in air

    Energy Technology Data Exchange (ETDEWEB)

    Ryberg, D.; Fierro, A.; Dickens, J.; Neuber, A. [Center for Pulsed Power and Power Electronics, Department of Electrical and Computer Engineering and Department of Physics, Texas Tech University, Lubbock, Texas 79409 (United States)

    2014-10-15

    A system for time-discretized spectroscopic measurements of the vacuum ultraviolet (VUV) emission from spark discharges in the 60-160 nm range has been developed for the study of early plasma-forming phenomena. The system induces a spark discharge in an environment close to atmospheric conditions created using a high speed puff value, but is otherwise kept at high vacuum to allow for the propagation of VUV light. Using a vertical slit placed 1.5 mm from the discharge the emission from a small cross section of the discharge is allowed to pass into the selection chamber consisting of a spherical grating, with 1200 grooves/mm, and an exit slit set to 100 μm. Following the exit slit is a photomultiplier tube with a sodium salicylate scintillator that is used for the time discretized measurement of the VUV signal with a temporal resolution limit of 10 ns. Results from discharges studied in dry air, Nitrogen, SF{sub 6}, and Argon indicate the emission of light with wavelengths shorter than 120 nm where the photon energy begins to approach the regime of direct photoionization.

  20. Overcurrent protection for the TFTR neutral beam sources during spark down

    International Nuclear Information System (INIS)

    Praeg, W.F.

    1979-01-01

    The accelerating grid of a neutral beam source (NBS) of the Tokamak Fusion Test Reactor (TFTR) operates at 120 kV and 65 A. The capacitance to ground between the switch tube (ST) and the NBS is C 1 approx. 5 nF (approx. 36 J). The arc and filament power supplies for the NBS float at 120 kV and have a capacitance to ground of C 2 approx. 2 nF (approx. 14 J). When the NBS sparks to ground, C 2 begins to discharge immediately. The ST impedance limits the fault current from the high voltage (HV) power supply to approx. 100 A until it disconnects the power source 1 begins to discharge. During spark down, fault currents are limited with a saturated time-delay transformer (STDT) connected between the ST and the NBS and with a snubber, which is in the arc and filament power leads, in connection with a spark gap. Alternatively, STDT's can be used for the HV and for the arc and filament power leads. This paper presents design details and experimental results of the overcurrent protection circuits

  1. Investigation of the energy dependence of breakdown properties with a DC spark setup

    CERN Document Server

    Hansen, Anita; Calatroni, S

    2009-01-01

    The Compact LInear Collider (CLIC) study is a site independent feasibility study aiming at the development of a realistic technology at an affordable cost for a future linear electron-positron collider. The European Organization for Nuclear Research (CERN) is one of the collaborators for the CLIC study.The CLIC Test Facility (CTF3) positioned at CERN provides testing of this technology, including the testing of the proposed radio-frequency (RF) structures in a two-beam concept to produce the necessary accelerating electric field as high as 100 MV/m to reach the goal of a nominal total energy of 3 TeV. One problem at such high accelerating fields is electrical discharges, i.e. sparks, damaging the inside of the RF structures as well as deflecting the trajectories of accelerated particles. A Direct Current (DC) spark test setup is in use at CERN to aid the understanding of electrical discharges under vacuum conditions, also called vacuum arcs. In contrast to the more complex CTF3 setup, the DC spark setup is si...

  2. submitter Triggering of a pressurized spark gap by a laser beam

    CERN Document Server

    Deutsch, F

    1968-01-01

    A delay line was discharged into a terminating resistor by a spark gap of coaxial design. The spark gap was triggered by a focused laser beam, introduced along the axis; a Q-switched ruby laser giving pulses of 20 ns duration and up to 50 MW power was used. The range of operation of the gap, formative time of the breakdown and jitter were investigated for different gases at pressures above atmospheric, gap widths of 4-10 mm and voltages of up to 120 kv. Mixtures of argon and nitrogen were found to have certain advantages, such as a low threshold for ionization by the laser beam, sufficient dielectric strength, low values of the formative-time jitter and chemical inertness. Formative times of down to about 1 ns and jitters below 1 ns were found. The laser power can be relatively low (0centerdot5-5 MW). An explanation for the breakdown mechanism is proposed.

  3. A 490 W transversely excited atmospheric CO2 spark gap laser with added H2

    Science.gov (United States)

    Zand, M.; Koushki, A. M.; Neshati, R.; Kia, B.; Khorasani, K.

    2018-02-01

    In this paper we present a new design for a high pulse repetition rate transversely excited atmospheric CO2 laser with ultraviolet pre-ionization. A new method of fast thyristor capacitor charging and discharging by a spark gap is used. The effect of H2 gas addition on the output and stability of a transversely excited atmospheric laser operating with a basic mixture of CO2, N2 and He is investigated. The output power was increased by adding H2 to the gas mixture ratio of CO2:N2:He:H2  =  1:1:8:0.5 at total pressure of 850 mbar. An average power of 490 W at 110 Hz with 4.5 J per pulse was obtained. The laser efficiency was 11.2% and oxygen gas was used in the spark gap for electron capture to reduce the recovery time and increase the repetition rate.

  4. Trace amount analysis using spark mass spectrometry

    International Nuclear Information System (INIS)

    Stefani, Rene

    1975-01-01

    Characteristics of spark mass spectrometers (ion source, properties of the ion beam, ion optics, and performance) and their use in qualitative and quantitative analysis are described. This technique is very interesting for the semi-quantitative analysis of trace amounts, down to 10 -8 atoms. Examples of applications such as the analysis of high purity materials and non-conducting mineral samples, and determination of carbon and gas trace amounts are presented. (50 references) [fr

  5. SPARK Version 1.1 user manual

    International Nuclear Information System (INIS)

    Weissenburger, D.W.

    1988-01-01

    This manual describes the input required to use Version 1.1 of the SPARK computer code. SPARK 1.1 is a library of FORTRAN main programs and subprograms designed to calculate eddy currents on conducting surfaces where current flow is assumed zero in the direction normal to the surface. Surfaces are modeled with triangular and/or quadrilateral elements. Lorentz forces produced by the interaction of eddy currents with background magnetic fields can be output at element nodes in a form compatible with most structural analysis codes. In addition, magnetic fields due to eddy currents can be determined at points off the surface. Version 1.1 features eddy current streamline plotting with optional hidden-surface-removal graphics and topological enhancements that allow essentially any orientable surface to be modeled. SPARK also has extensive symmetry specification options. In order to make the manual as self-contained as possible, six appendices are included that present summaries of the symmetry options, topological options, coil options and code algorithms, with input and output examples. An edition of SPARK 1.1 is available on the Cray computers at the National Magnetic Fusion Energy Computer Center at Livermore, California. Another more generic edition is operational on the VAX computers at the Princeton Plasma Physics Laboratory and is available on magnetic tape by request. The generic edition requires either the GKS or PLOT10 graphics package and the IMSL or NAG mathematical package. Requests from outside the United States will be subject to applicable federal regulations regarding dissemination of computer programs. 22 refs

  6. Shoulder replacement - discharge

    Science.gov (United States)

    Total shoulder arthroplasty - discharge; Endoprosthetic shoulder replacement - discharge; Partial shoulder replacement - discharge; Partial shoulder arthroplasty - discharge; Replacement - shoulder - discharge; Arthroplasty - shoulder - discharge

  7. Effects of spark plug configuration on combustion and emission characteristics of a LPG fuelled lean burn SI engine

    Science.gov (United States)

    Ravi, K.; Khan, Manazir Ahmed; Pradeep Bhasker, J.; Porpatham, E.

    2017-11-01

    Introduction of technological innovation in automotive engines in reducing pollution and increasing efficiency have been under contemplation. Gaseous fuels have proved to be a promising way to reduce emissions in Spark Ignition (SI) engines. In particular, LPG settled to be a favourable fuel for SI engines because of their higher hydrogen to carbon ratio, octane rating and lower emissions. Wide ignition limits and efficient combustion characteristics make LPG suitable for lean burn operation. But lean combustion technology has certain drawbacks like poor flame propagation, cyclic variations etc. Based on copious research it was found that location, types and number of spark plug significantly influence in reducing cyclic variations. In this work the influence of single and dual spark plugs of conventional and surface discharge electrode type were analysed. Dual surface discharge electrode spark plug enhanced the brake thermal efficiency and greatly reduced the cyclic variations. The experimental results show that rate of heat release and pressure rise was more and combustion duration was shortened in this configuration. On the emissions front, the NOx emission has increased whereas HC and CO emissions were reduced under lean condition.

  8. Dissociation dynamics of CH3I in electric spark induced breakdown revealed by time-resolved laser induced breakdown spectroscopy

    International Nuclear Information System (INIS)

    Wang, Yang; Liu, Wei-long; Song, Yun-fei; Duo, Li-ping; Liu, Yu-qiang; Yang, Yan-qiang

    2015-01-01

    Highlights: • Emission of electric spark dissociation of CH 3 I is similar to its fs LIBS. • We use fs laser induced breakdown as a simulation for electric spark dissociation. • The I 2 molecule formation is directly observed in the time-resolved LIBS. • Bimolecular collision of I ∗ and CH 3 I is responsible for the formation of I 2 . - Abstract: The electric discharge spark dissociation of gas CH 3 I is found to be similar to its femtosecond laser photodissociation. The almost identical spectra of the two processes show that their initial ionization conditions are very similar. The initial ionization followed by molecular fragmentation is proposed as the dissociation mechanism, in which the characteristic emissions of I + , CH 3 , CH 2 , CH, H, and I 2 are identified as the dissociation products. The emission band of 505 nm I 2 is clearly observed in the time-resolved laser induced breakdown spectroscopy (LIBS). The dynamic curve indicates that I 2 ∗ molecules are formed after the delay time of ∼4.7 ns. The formation of I 2 ∗ molecule results from the bimolecular collision of the highly excited iodine atom I ∗ ( 4 P) and CH 3 I molecule. This dynamical information can help understand the process of electric discharge spark dissociation of CH 3 I

  9. A comparison of electrochemically pre-treated and spark-platinized carbon fiber microelectrode. Measurement of 8-oxo-7,8-dihydro-2′-deoxyguanosine in human urine and plasma

    Energy Technology Data Exchange (ETDEWEB)

    Bartosova, Z.; Riman, D. [Department of Analytical Chemistry, Palacky University, Faculty of Science, 17.listopadu 12, CZ-771 46 Olomouc (Czech Republic); Halouzka, V. [Department of Analytical Chemistry, Palacky University, Faculty of Science, 17.listopadu 12, CZ-771 46 Olomouc (Czech Republic); Department of Physics and Materials Engineering, Faculty of Technology, Tomas Bata University in Zlin, nam. T.G. Masaryka 275, CZ-76001 Zlin (Czech Republic); Vostalova, J.; Simanek, V. [Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacky University, Hnevotinska 3, CZ-775 15 Olomouc (Czech Republic); Hrbac, J., E-mail: jhrbac@atlas.cz [Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, CZ-625 00 Brno (Czech Republic); Jirovsky, D., E-mail: david.jirovsky@upol.cz [Department of Analytical Chemistry, Palacky University, Faculty of Science, 17.listopadu 12, CZ-771 46 Olomouc (Czech Republic)

    2016-09-07

    A novel method of carbon fiber microelectrode activation using spark discharge was demonstrated and compared to conventional electrochemical pretreatment by potential cycling. The spark discharge was performed at 800 V between the microelectrode connected to positive pole of the power supply and platinum counter electrode. Spark discharge led both to trimming of the fiber tip into conical shape and to the modification of carbon fiber microelectrode with platinum, as proven by scanning electron microscopy and electron dispersive X-ray spectroscopy. After the characterization of electrochemical properties using ferricyanide voltammetry, the activated electrodes were used for electrochemical analysis of 8-oxo-7,8-dihydro-2′-deoxyguanosine, an oxidative stress marker. Subnanomolar detection limits (0.55 nmol L{sup −1}) in high-performance liquid chromatography were achieved for spark platinized electrodes incorporated into the flow detection cell. - Highlights: • Novel method of carbon fiber microelectrode activation and platinization using spark discharge. • The activation procedure is efficient, fast and solvent-free. • Modification of the surface and the shape of the carbon fiber microelectrode during the process. • The spark-etched platinized carbon fiber sensors are highly sensitive. • The sensor was successfully applied to HPLC analysis of 8-oxo-7,8-dihydro-2′-deoxyguanosine in plasma and urine.

  10. Big Data Analytics with Datalog Queries on Spark.

    Science.gov (United States)

    Shkapsky, Alexander; Yang, Mohan; Interlandi, Matteo; Chiu, Hsuan; Condie, Tyson; Zaniolo, Carlo

    2016-01-01

    There is great interest in exploiting the opportunity provided by cloud computing platforms for large-scale analytics. Among these platforms, Apache Spark is growing in popularity for machine learning and graph analytics. Developing efficient complex analytics in Spark requires deep understanding of both the algorithm at hand and the Spark API or subsystem APIs (e.g., Spark SQL, GraphX). Our BigDatalog system addresses the problem by providing concise declarative specification of complex queries amenable to efficient evaluation. Towards this goal, we propose compilation and optimization techniques that tackle the important problem of efficiently supporting recursion in Spark. We perform an experimental comparison with other state-of-the-art large-scale Datalog systems and verify the efficacy of our techniques and effectiveness of Spark in supporting Datalog-based analytics.

  11. 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.

  12. Sparking investment in Ontario's power generation industry

    International Nuclear Information System (INIS)

    Allen, J.

    2004-01-01

    This paper discusses the business strategy needed to spark investment in Ontario's power generation industry. It examines the process of decision making and investing in an uncertain environment. The paper suggests that any strategy based on one view of the future courts trouble and that strategic flexibility can prepare for what cannot be predicted. Finally the paper suggests that Ontario needs to create a stable policy and regulatory environment that allows investors to fulfill reasonable expectations and investors need to place bets that provide the flexibility to respond quickly to changing market conditions

  13. Hybrid employment recommendation algorithm based on Spark

    Science.gov (United States)

    Li, Zuoquan; Lin, Yubei; Zhang, Xingming

    2017-08-01

    Aiming at the real-time application of collaborative filtering employment recommendation algorithm (CF), a clustering collaborative filtering recommendation algorithm (CCF) is developed, which applies hierarchical clustering to CF and narrows the query range of neighbour items. In addition, to solve the cold-start problem of content-based recommendation algorithm (CB), a content-based algorithm with users’ information (CBUI) is introduced for job recommendation. Furthermore, a hybrid recommendation algorithm (HRA) which combines CCF and CBUI algorithms is proposed, and implemented on Spark platform. The experimental results show that HRA can overcome the problems of cold start and data sparsity, and achieve good recommendation accuracy and scalability for employment recommendation.

  14. Anticipating Change, Sparking Innovation: Framing the Future

    Science.gov (United States)

    Finnegan, John R.; Spencer, Harrison C.

    2015-01-01

    As the 100th anniversary of the 1915 Welch-Rose report approaches, the Association of Schools and Programs of Public Health (ASPPH) has been pursuing two initiatives to spark innovation in academic partnerships for enhancing population health: (1) Framing the Future: The Second 100 Years of Education for Public Health and (2) Reconnecting Public Health and Care Delivery to Improve the Health of Populations. We describe how ASPPH-member schools and programs accredited by the Council on Education for Public Health, along with their extraordinarily diverse array of partners, are working to improve education that better prepares health professionals to meet 21st-century population health needs. PMID:25706017

  15. Discharge behaviors during plasma electrolytic oxidation on aluminum alloy

    International Nuclear Information System (INIS)

    Liu, Run; Wu, Jie; Xue, Wenbin; Qu, Yao; Yang, Chaolin; Wang, Bin; Wu, Xianying

    2014-01-01

    A plasma electrolytic oxidation (PEO) process was performed on the 2024 aluminum alloy in silicate electrolyte to fabricate ceramic coatings under a constant voltage. Optical emission spectroscopy (OES) was employed to evaluate the characteristics of plasma discharge during PEO process. The plasma electron temperature and density were obtained by analyzing the spectral lines of OES, and the atomic ionization degree in discharge zone was calculated in terms of Saha thermal ionization equation. The illumination intensity of plasma discharge and the temperature in the interior of alloy were measured. Combining the surface morphology and cross-sectional microstructure with the optical emission spectra and illumination at different discharge stage, a discharge model in the growth of PEO ceramic coatings was proposed. It is found that there are two discharge modes of type A with small spark size and type B with large spark size, and the latter only appears in the intermediate stage of PEO process. The illumination intensity has a maximum value in the initial stage of oxidation with many sparks of discharge type A. The electron temperature in plasma discharge zone is about 3000 K–7000 K and atomic ionization degree of Al is about 2.0 × 10 −5 –7.2 × 10 −3 , which depend on discharge stage. The discharge type B plays a key role on the electron temperature and atomic ionization degree. The electron density keeps stable in the range of about 8.5 × 10 21  m −3 –2.6 × 10 22  m −3 . - Highlights: • The characteristics of PEO plasma discharge was evaluated by OES. • Electron temperature, concentration, atomic ionization degree were calculated. • Discharge model for the growth of PEO coatings was proposed. • Temperature in the interior of alloy during PEO process was measured

  16. Development of a SPARK Training Dataset

    Energy Technology Data Exchange (ETDEWEB)

    Sayre, Amanda M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Olson, Jarrod R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-03-01

    In its first five years, the National Nuclear Security Administration’s (NNSA) Next Generation Safeguards Initiative (NGSI) sponsored more than 400 undergraduate, graduate, and post-doctoral students in internships and research positions (Wyse 2012). In the past seven years, the NGSI program has, and continues to produce a large body of scientific, technical, and policy work in targeted core safeguards capabilities and human capital development activities. Not only does the NGSI program carry out activities across multiple disciplines, but also across all U.S. Department of Energy (DOE)/NNSA locations in the United States. However, products are not readily shared among disciplines and across locations, nor are they archived in a comprehensive library. Rather, knowledge of NGSI-produced literature is localized to the researchers, clients, and internal laboratory/facility publication systems such as the Electronic Records and Information Capture Architecture (ERICA) at the Pacific Northwest National Laboratory (PNNL). There is also no incorporated way of analyzing existing NGSI literature to determine whether the larger NGSI program is achieving its core safeguards capabilities and activities. A complete library of NGSI literature could prove beneficial to a cohesive, sustainable, and more economical NGSI program. The Safeguards Platform for Automated Retrieval of Knowledge (SPARK) has been developed to be a knowledge storage, retrieval, and analysis capability to capture safeguards knowledge to exist beyond the lifespan of NGSI. During the development process, it was necessary to build a SPARK training dataset (a corpus of documents) for initial entry into the system and for demonstration purposes. We manipulated these data to gain new information about the breadth of NGSI publications, and they evaluated the science-policy interface at PNNL as a practical demonstration of SPARK’s intended analysis capability. The analysis demonstration sought to answer the

  17. Design of a laser-triggered driver for fast capillary discharge

    Science.gov (United States)

    Schmidt, J.; Kolacek, K.; Bohacek, V.; Prukner, V.; Frolov, O.; Straus, J.

    2004-03-01

    We are developing a new upgraded capillary discharge device. The assembled set-up consists of a Marx generator, a pulse forming line, a gas-filled laser-triggered spark gap and a ceramic capillary. The special attention has been paid to the design of the spark gap. The laser triggering of this spark gap ensures a very low jitter in comparison with the present capillary discharge device CAPEX, where the main spark gap works in a self-breakdown regime. The description of the assembled apparatus, the main predicted parameters of the designed device (such as capillary current, capillary current rise-rte, and/or voltage at the end of pulse forming line) are presented.

  18. Generation of intense soft X-rays from capillary discharge plasmas

    Indian Academy of Sciences (India)

    At Laser Plasma Division, RRCAT, a program on high voltage capillary discharge had been started. The system consists of a 400 kV Marx bank, water line capacitor, spark gap and capillary chamber. The initial results of the emission of intense short soft X-ray pulses (5–10 ns) from the capillary discharge are reported.

  19. Simulation of the Electromagnetic Properties of a Pestov Spark Counter

    CERN Document Server

    Pestov, Yu N; CERN. Geneva; Schmidt, H R; Thoma, P

    1997-01-01

    Both the electrostatic and the electromagnetic properties of the proposed Pestov Spark counter for the CERN-LHC experiment ALICE were calculated employing the HF simulation package MAFIA. The simulations helped to design a frontend readout board of high bandwidth for the transmission of the very fast signal induced by the spark to the frontend electronics.

  20. Detector for recoil nuclei stopping in the spark chamber gas

    International Nuclear Information System (INIS)

    Aleksanyan, A.S.; Asatiani, T.L.; Ivanov, V.I.; Mkrtchyan, G.G.; Pikhtelev, R.N.

    1974-01-01

    A detector consisting of the combination of a drift and a wide gap spark chambers and designed to detect recoil nuclei stopping in the spark chamber gas is described. It is shown, that by using an appropriate discrimination the detector allows to detect reliably the recoil nuclei in the presence of intensive electron and γ-quanta beams

  1. knock characteristics analysis of a supercharged spark ignition

    African Journals Online (AJOL)

    user

    and manufacturing of spark ignition engines with improved performance. Understanding factors influencing knock in spark ignition engines will help designers understand how to manage knock in engines. Various designs over the years have been introduced in internal combustion engines with the aim of improving.

  2. NIPPLE DISCHARGE

    Directory of Open Access Journals (Sweden)

    T. N. Bukharova

    2008-01-01

    Full Text Available According to the data available in the literature, as high as 50% of women have benign breast tumors frequently accompanied by nip- ple discharge. Nipple discharge may be serous, bloody, purulent, and colostric. The most common causes are breast abscess, injury, drugs, prolactinoma, intraductal pappiloma, ductal ectasia, intraductal cancer (not more than 10%.

  3. Characteristics of the Arcing Plasma Formation Effect in Spark-Assisted Chemical Engraving of Glass, Based on Machine Vision.

    Science.gov (United States)

    Ho, Chao-Ching; Wu, Dung-Sheng

    2018-03-22

    Spark-assisted chemical engraving (SACE) is a non-traditional machining technology that is used to machine electrically non-conducting materials including glass, ceramics, and quartz. The processing accuracy, machining efficiency, and reproducibility are the key factors in the SACE process. In the present study, a machine vision method is applied to monitor and estimate the status of a SACE-drilled hole in quartz glass. During the machining of quartz glass, the spring-fed tool electrode was pre-pressured on the quartz glass surface to feed the electrode that was in contact with the machining surface of the quartz glass. In situ image acquisition and analysis of the SACE drilling processes were used to analyze the captured image of the state of the spark discharge at the tip and sidewall of the electrode. The results indicated an association between the accumulative size of the SACE-induced spark area and deepness of the hole. The results indicated that the evaluated depths of the SACE-machined holes were a proportional function of the accumulative spark size with a high degree of correlation. The study proposes an innovative computer vision-based method to estimate the deepness and status of SACE-drilled holes in real time.

  4. Ileostomy - discharge

    Science.gov (United States)

    ... dried fruits (such as raisins), mushrooms, chunky relishes, coconut, and some Chinese vegetables. Tips for when no ... ask your doctor Living with your ileostomy Low-fiber diet Small bowel resection - discharge Total colectomy or ...

  5. Unraveling the Image of Commutation Spark Generated in Universal Motors

    Science.gov (United States)

    Hanazawa, Tamio; Almazroui, Ali; Egashira, Torao

    A universal motor, which is mainly used in vacuum cleaners, generates commutation sparks at the moment when the brush and the commutator segment are separated from each other during rotation. This study investigates the mechanism of commutation spark generation by analyzing high-speed camera images and its electrical aspect. We invented a new external trigger method that used laser light as the trigger signal for the shuttering a high-speed camera. This method enabled us to photograph sparks on any desired commutator segments during high-speed rotation, and that made the analysis after photographing easier. This paper shows that commutation sparks in universal motors are generated on every other commutator segment and at the peak of pulses in the voltage between the brush and commutator segment. Other aspects are also clarified, such as the generation of the singular and plural number of sparks on one commutator segment at a time, the time from the moment of spark generation to extinction, and spark generation during a single rotation.

  6. Target fabrication using laser and spark erosion machining

    International Nuclear Information System (INIS)

    Clement, X.; Coudeville, A.; Eyharts, P.; Perrine, J.P.; Rouillard, R.

    1982-01-01

    Fabrication of laser fusion targets requires a number of special techniques. We have developed both laser and spark erosion machining to produce minute parts of complex targets. A high repetition rate YAG laser at double frequency is used to etch various materials. For example, marks or patterns are often necessary on structured or advanced targets. The laser is also used to thin down plastic coated stalks. A spark erosion system has proved to be a versatile tool and we describe current fabrication processes like cutting, drilling, and ultra precise machining. Spark erosion has interesting features for target fabrication: it is a highly controllable and reproducible technique as well as relatively inexpensive

  7. Three-electrode gas switches with electrodynamical acceleration of a discharge channel.

    Science.gov (United States)

    Kovalchuk, B M; Kim, A A; Kharlov, A V; Kumpyak, E V; Tsoy, N V; Vizir, V V; Zorin, V B

    2008-05-01

    High voltage, high current, and high Coulomb transfer closing switches are required for many high power pulsed systems. There are a few alternatives for closing switches, for example, ignitrons, vacuum switches, solid-state switches, high pressure gas switches (spark gaps), and some others. The most popular closing switches up to date are spark gaps due to relatively simple design, robustness, easily field maintenance, and repair. Main drawback of spark gaps is limited lifetime, which is related directly or indirectly to erosion of the electrodes. Multichannel switches and switches with moving arc have been proposed to prevent the electrodes erosion. This study investigates switches, where a spark channel is initiated in a three-electrode layout and then the spark accelerates due to electrodynamic force and moves along the extended electrodes. At a given current amplitude, the diameter of the extended electrodes allows to control the spark velocity and hence, the erosion of the electrodes providing the required lifetime. The first switch is designed for 24 kV charging voltage and approximately 4 C total charge transfer. This spark gap was tested at 25 kA peak current in 40 000 shots in a single polarity discharge and in 20 000 shots in bipolar discharge. Second spark gap is designed for 24 kV charging voltage and approximately 70 C total charge transfer. It was tested in 22 000 shots, at a current of 250 kA with a pulse length of 360 mus. In this paper, we present design of these spark gaps and trigger generator, describe the test bed, and present the results of the tests.

  8. Hazard of electrostatic generation in a pneumatic conveying system: electrostatic effects on the accuracy of electrical capacitance tomography measurements and generation of spark

    International Nuclear Information System (INIS)

    Zhang, Yan; Wang, Chi-Hwa; Liang, Yung Chii

    2008-01-01

    The study of the hazard of electrostatic generation in pneumatic conveying systems was attempted by examining the sensitivity of electrical capacitance tomography (ECT) and the phenomena of spark generation due to strong electrostatics. The influence on ECT measurement accuracy of an electrostatic charge was analysed with reference to a switch capacitor configuration model. Consequently, it was found that the electrostatic charge introduced at the bend with sharp angles influenced the ECT results most significantly in pneumatic conveying systems, especially for the cases where a spark was generated. The investigation of spark generation indicated that a strong electrostatic charge can cause major discharges inside or outside the pipeline to damage the experimental instrument in severe cases

  9. Spatiotemporally resolved characteristics of a gliding arc discharge in a turbulent air flow at atmospheric pressure

    Science.gov (United States)

    Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas; Aldén, Marcus; Larsson, Anders; Kusano, Yukihiro; Li, Zhongshan

    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 and transitions among the different types of discharges, were investigated using simultaneously optical and electrical diagnostics. The glow-type discharge shows sinusoidal-like voltage and current waveforms with a peak current of hundreds of milliamperes. The frequency of the emission intensity variation of the glow-type discharge is the same as that of the electronic power dissipated in the plasma column. The glow-type discharge can transfer into a spark discharge characterized by a sharp peak current of several amperes and a sudden increase of the brightness in the plasma column. Transitions can also be found to take place from spark-type discharges to glow-type discharges. Short-cutting events were often observed as the intermediate states formed during the spark-glow transition. Three different types of short-cutting events have been observed to generate new current paths between two plasma channel segments, and between two electrodes, as well as between the channel segment and the electrodes, respectively. The short-cut upper part of the plasma column that was found to have no current passing through can be detected several hundreds of microseconds after the short-cutting event. The voltage recovery rate, the period of AC voltage-driving signal, the flow rates and the rated input powers were found to play an important role in affecting the transitions among the different types of discharges.

  10. Exploring the Performance of Spark for a Scientific Use Case

    Energy Technology Data Exchange (ETDEWEB)

    Sehrish, Saba [Fermilab; Kowalkowski, Jim [Fermilab; Paterno, Marc [Fermilab

    2016-01-01

    We present an evaluation of the performance of a Spark implementation of a classification algorithm in the domain of High Energy Physics (HEP). Spark is a general engine for in-memory, large-scale data processing, and is designed for applications where similar repeated analysis is performed on the same large data sets. Classification problems are one of the most common and critical data processing tasks across many domains. Many of these data processing tasks are both computation- and data-intensive, involving complex numerical computations employing extremely large data sets. We evaluated the performance of the Spark implementation on Cori, a NERSC resource, and compared the results to an untuned MPI implementation of the same algorithm. While the Spark implementation scaled well, it is not competitive in speed to our MPI implementation, even when using significantly greater computational resources.

  11. Phase characterisation in spark plasma sintered TiPt alloy

    CSIR Research Space (South Africa)

    Chikosha, S

    2011-12-01

    Full Text Available The conclusions drawn from this presentation are that Spark Plasma Sintering (SPS) of equiatomic BE TiPt powder produces fully sintered specimens, with incomplete homogenisation. There is a need for improved furnace atmosphere control so...

  12. Pulse-actuated fuel-injection spark plug

    Science.gov (United States)

    Murray, Ian; Tatro, Clement A.

    1978-01-01

    A replacement spark plug for reciprocating internal combustion engines that functions as a fuel injector and as a spark plug to provide a "stratified-charge" effect. The conventional carburetor is retained to supply the main fuel-air mixture which may be very lean because of the stratified charge. The replacement plug includes a cylindrical piezoelectric ceramic which contracts to act as a pump whenever an ignition pulse is applied to a central rod through the ceramic. The rod is hollow at its upper end for receiving fuel, it is tapered along its lower length to act as a pump, and it is flattened at its lower end to act as a valve for fuel injection from the pump into the cylinder. The rod also acts as the center electrode of the plug, with the spark jumping from the plug base to the lower end of the rod to thereby provide spark ignition that has inherent proper timing with the fuel injection.

  13. Multiple Spark-Generated Bubble Interactions

    Science.gov (United States)

    Khoo, Boo Cheong; Adikhari, Deepak; Fong, Siew Wan; Klaseboer, Evert

    The complex interactions of two and three spark-generated bubbles are studied using high speed photography. The corresponding simulations are performed using a 3D Boundary Element Method (BEM) code. The bubbles generated are between 3 to 5 mm in radius, and they are either in-phase or out-of-phase with one another. The possible interaction phenomena between two identically sized bubbles are summarized. Depending on their relative distances and phase differences, they can coalesce, jet towards or away from one another, split into smaller bubbles, or 'catapult' away from one another. The 'catapult' effect can be utilized to generated high speed jet in the absence of a solid boundary or shockwave. Also three bubble interactions are highlighted. Complicated phenomena such as bubble forming an elliptical shape and bubble splitting are observed. The BEM simulations provide insight into the physics of the phenomena by providing details such as detailed bubble shape changes (experimental observations are limited by the temporal and spatial resolution), and jet velocity. It is noted that the well-tested BEM code [1,2] utilized here is computationally very efficient as compared to other full-domain methods since only the bubble surface is meshed.

  14. Radiofrequency spark chambers and delay line resonators

    International Nuclear Information System (INIS)

    Sayag, Jacques

    1971-01-01

    According to a suggestion of A. Kastler, a spark chamber was excited by an undamped radiofrequency pulse and tracks about 1 mm wide obtained; the result was interpreted by computation of the coefficients of electronic amplification and partial ambipolar diffusion. This work led us to the construction of a new fast triggering undamped wave-train generator of very high tension (patent taken out by the C.E.A. under the no.: EN 7 134 650 the 27.9.1971). Since this apparatus uses a resonant storage line, its design implied a precise knowledge of high impedance delay lines. The experimental radiofrequency spectra of the input impedance of opened or short-circuited lines were plotted completely and analysed by the circuits theory, new measuring methods were established, dispersion relations accurately checked and the equivalence of the formulas, within the third order, with theses of Debye's Dipolar Absorption demonstrated. General properties of Hilbert's transform were also investigated. From the experimental point of view, the electromagnetic energy storage process was extended to the case of a liquid nitrogen-immersed resonant delay line. The good behavior of the cryogenic experiment, where the main difficulty of icing was overcame by the construction of special electrodes, offers great promise for extrapolation to superconductivity. (author) [fr

  15. Analysis of magnesium and copper in aluminum alloys with high repetition rate laser-ablation spark-induced breakdown spectroscopy

    Science.gov (United States)

    He, Xiaoyong; Dong, Bo; Chen, Yuqi; Li, Runhua; Wang, Fujuan; Li, Jiaoyang; Cai, Zhigang

    2018-03-01

    In order to improve the analytical speed and performance of laser-ablation based atomic emission spectroscopy, high repetition rate laser-ablation spark-induced breakdown spectroscopy (HRR LA-SIBS) was first developed. Magnesium and copper in aluminum alloys were analyzed with this technique. In the experiments, the fundamental output of an acousto-optically Q-switched Nd:YAG laser operated at 1 kHz repetition rate with low pulse energy and 120 ns pulse width was used to ablate the samples and the plasma emission was enhanced by spark discharge. The spectra were recorded with a compact fiber spectrometer with non-intensified charge-coupled device in non-gating mode. Different parameters relative with analytical performance, such as capacitance, voltage, laser pulse energy were optimized. Under current experimental conditions, calibration curves of magnesium and copper in aluminum alloys were built and limits of detection of them were determined to be 14.0 and 9.9 ppm by HRR LA-SIBS, respectively, which were 8-12 folds better than that achieved by HRR LA under similar experimental condition without spark discharge. The analytical sensitivities are close to those obtained with conventional LIBS but with improved analytical speed as well as possibility of using compact fiber spectrometer. Under high repetition rate operation, the noise level can be decreased and the analytical reproducibility can be improved obviously by averaging multiple measurements within short time. High repetition rate operation of laser-ablation spark-induced breakdown spectroscopy is very helpful for improving analytical speed. It is possible to find applications in fast elements analysis, especially fast two-dimension elemental mapping of solid samples.

  16. [Application of spark erosion technology in manufacture of implant prosthesis].

    Science.gov (United States)

    Cui, H Y; DI, P; Li, J H; Lin, Y; Liu, R R

    2015-04-18

    To evaluate the influence of the implant-supported porcelain bridges made from non-precious metals using spark erosion techniques, and to discuss the feasibility and details of making the implant restoration by spark erosion technique. The study included 12 patients (9 males and 3 females) with 92 units implant-supported non-precious porcelain bridge from Sep. 2011 to Feb. 2013. All the patients received implant treatment in Department of Oral Implantology, Peking University School and Hospital of Stomatology. The total of 52 implants, were from Nobel Biocare implant system, Camlog implant system and Ankylos implant system. The implant analogs were connected in sequence with a copper wire to guarantee conductivity. The implant electrodes represented one electrode and the superstructure the other. During spark-erosion machining, the cast holding the implant electrodes and the prosthetic framework were moved toward one another, causing an electrical erosion of the protruding elements. After the spark-erosion machining, the minimum gap between the framework and abutment was 0.21 mm, which was two units bridge. The maximum was 2.59 mm, which was 11 units bridge with 6 implants. The average gap was 0.68 mm. After the spark-erosion machining, the bridge fitted well with the passive position stability. The method of making implant-supported non-precious porcelain bridge reduces costs on patients. Spark erosion has the potential to provide implant framework with an excellent fit. The patients are satisfied with the clinical results.

  17. Nanomaterials synthesis at atmospheric pressure using nanosecond discharges

    International Nuclear Information System (INIS)

    Pai, David Z

    2011-01-01

    The application of nanosecond discharges towards nanomaterials synthesis at atmospheric pressure is explored in this perspective article. First, various plasma sources are evaluated in terms of the energy used to include one atom into the nanomaterial, which is shown to depend strongly on the electron temperature. Because of their high average electron temperature, nanosecond discharges could be used to achieve nanofabrication at a lower energy cost, and therefore with better efficiency, than with other plasma sources at atmospheric pressure. Transient spark discharges and nanosecond repetitively pulsed (NRP) discharges are suggested as particularly useful examples of nanosecond discharges generated at high repetition frequency. Nanosecond discharges also generate fast heating and cooling rates that could be exploited to produce metastable nanomaterials.

  18. Esophagectomy - discharge

    Science.gov (United States)

    ... 000241.htm Esophagectomy - discharge To use the sharing features on this page, please enable JavaScript. You had ... up or down stairs, or ride in a car. Be sure to rest after being active. If it hurts when ... In the bathroom , install safety bars to help you get in and out ...

  19. Mastectomy - discharge

    Science.gov (United States)

    ... had breast reconstruction surgery with implants or natural tissue . What to Expect at Home Full recovery may take ... lump removal Breast reconstruction - implants Breast reconstruction - natural ... breast surgery - discharge Mastectomy and breast reconstruction - what to ask your doctor Wet-to-dry dressing ...

  20. Radiological discharges

    International Nuclear Information System (INIS)

    Woodliffe, J.

    1990-01-01

    Current practice of North Sea States on the discharge and disposal of liquid radioactive wastes to the North Sea are based on the declaration issued at the Second International Conference on the Protection of the North Sea, known as the London Declaration. This has three main points the first of which emphasises the application of the Best Available Technology to protect the North Sea, the second provides a framework on which future controls on radioactive discharges should be based. The third identifies two parts of the framework; to take into account the recommendations of international organizations and that any repositories of radioactive waste which are built should not pollute the North Sea. This chapter looks at how the concensus based on the London Declaration is working, gauges the progress made in the implementation of the policy goal, identifies existing and future areas for concern and proposes ways of strengthening the control of radioactive discharges. The emphasis is on the United Kingdom practice and regulations for liquid wastes, most of which comes from the Sellafield Reprocessing Plant. (author)

  1. Geometric improvement of electrochemical discharge micro-drilling using an ultrasonic-vibrated electrolyte

    Science.gov (United States)

    Han, Min-Seop; Min, Byung-Kwon; Lee, Sang Jo

    2009-06-01

    Electrochemical discharge machining (ECDM) is a spark-based micromachining method especially suitable for the fabrication of various microstructures on nonconductive materials, such as glass and some engineering ceramics. However, since the spark discharge frequency is drastically reduced as the machining depth increases ECDM microhole drilling has confronted difficulty in achieving uniform geometry for machined holes. One of the primary reasons for this is the difficulty of sustaining an adequate electrolyte flow in the narrow gap between the tool and the workpiece, which results in a widened taper at the hole entrance, as well as a significant reduction of the machining depth. In this paper, ultrasonic electrolyte vibration was used to enhance the machining depth of the ECDM drilling process by assuring an adequate electrolyte flow, thus helping to maintain consistent spark generation. Moreover, the stability of the gas film formation, as well as the surface quality of the hole entrance, was improved with the aid of a side-insulated electrode and a pulse-power generator. The side-insulated electrode prevented stray electrolysis and concentrated the spark discharge at the tool tip, while the pulse voltage reduced thermal damage to the workpiece surface by introducing a periodic pulse-off time. Microholes were fabricated in order to investigate the effects of ultrasonic assistance on the overcut and machining depth of the holes. The experimental results demonstrated that the possibility of consistent spark generation and the machinability of microholes were simultaneously enhanced.

  2. Geometric improvement of electrochemical discharge micro-drilling using an ultrasonic-vibrated electrolyte

    International Nuclear Information System (INIS)

    Han, Min-Seop; Min, Byung-Kwon; Lee, Sang Jo

    2009-01-01

    Electrochemical discharge machining (ECDM) is a spark-based micromachining method especially suitable for the fabrication of various microstructures on nonconductive materials, such as glass and some engineering ceramics. However, since the spark discharge frequency is drastically reduced as the machining depth increases ECDM microhole drilling has confronted difficulty in achieving uniform geometry for machined holes. One of the primary reasons for this is the difficulty of sustaining an adequate electrolyte flow in the narrow gap between the tool and the workpiece, which results in a widened taper at the hole entrance, as well as a significant reduction of the machining depth. In this paper, ultrasonic electrolyte vibration was used to enhance the machining depth of the ECDM drilling process by assuring an adequate electrolyte flow, thus helping to maintain consistent spark generation. Moreover, the stability of the gas film formation, as well as the surface quality of the hole entrance, was improved with the aid of a side-insulated electrode and a pulse-power generator. The side-insulated electrode prevented stray electrolysis and concentrated the spark discharge at the tool tip, while the pulse voltage reduced thermal damage to the workpiece surface by introducing a periodic pulse-off time. Microholes were fabricated in order to investigate the effects of ultrasonic assistance on the overcut and machining depth of the holes. The experimental results demonstrated that the possibility of consistent spark generation and the machinability of microholes were simultaneously enhanced

  3. A SPARK BASED COMPUTING FRAMEWORK FOR SPATIAL DATA

    Directory of Open Access Journals (Sweden)

    F. Xiao

    2017-10-01

    Full Text Available In this paper, a novel Apache Spark-based framework for spatial data processing is proposed, which includes 4 layers: spatial data storage, spatial RDDs, spatial operations, and spatial query language. The spatial data storage layer uses HDFS to store large size of spatial vector/raster data in the distributed cluster. The spatial RDDs are the abstract logical dataset of spatial data types, and can be transferred to the spark cluster to conduct spark transformations and actions. The spatial operations layer is a series of processing on spatial RDDs, such as range query, k nearest neighbour and spatial join. The spatial query language is a user-friendly interface which provide people not familiar with Spark with a comfortable way to operation the spatial operation. Compared with other spatial frameworks based on Spark, it is highlighted that spatial indexes like grid, R-tree are used for data storage and query. Extensive experiments on real system prototype and real datasets show that better performance can be achieved.

  4. A spectroscopy study of gasoline partially premixed compression ignition spark assisted combustion

    International Nuclear Information System (INIS)

    Pastor, J.V.; García-Oliver, J.M.; García, A.; Micó, C.; Durrett, R.

    2013-01-01

    Highlights: ► PPC combustion combined with spark assistance and gasoline fuel on a CI engine. ► Chemiluminescence of different chemical species describes the progress of combustion reaction. ► Spectra of a novel combustion mode under SACI conditions is described. ► UV–Visible spectrometry, high speed imaging and pressure diagnostic were employed for analysis. - Abstract: Nowadays many research efforts are focused on the study and development of new combustion modes, mainly based on the use of locally lean air–fuel mixtures. This characteristic, combined with exhaust gas recirculation, provides low combustion temperatures that reduces pollutant formation and increases efficiency. However these combustion concepts have some drawbacks, related to combustion phasing control, which must be overcome. In this way, the use of a spark plug has shown to be a good solution to improve phasing control in combination with lean low temperature combustion. Its performance is well reported on bibliography, however phenomena involving the combustion process are not completely described. The aim of the present work is to develop a detailed description of the spark assisted compression ignition mode by means of application of UV–Visible spectrometry, in order to improve insight on the combustion process. Tests have been performed in an optical engine by means of broadband radiation imaging and emission spectrometry. The engine hardware is typical of a compression ignition passenger car application. Gasoline was used as the fuel due to its low reactivity. Combining broadband luminosity images with pressure-derived heat-release rate and UV–Visible spectra, it was possible to identify different stages of the combustion reaction. After the spark discharge, a first flame kernel appears and starts growing as a premixed flame front, characterized by a low and constant heat-release rate in combination with the presence of remarkable OH radical radiation. Heat release increases

  5. Simultaneous emissions of X-rays and microwaves from long laboratory sparks and downward lightning leaders

    Science.gov (United States)

    Montanya, J.; Oscar, V. D. V.; Tapia, F. F.

    2017-12-01

    Since the discovery of the Terrestrial Gamma-ray Flashes more than 20 years ago, investigations on high energy emissions from natural lightning and high voltage laboratory sparks gained significant interest. X-ray emissions from lightning as well from high voltage laboratory sparks have in common the role played by negative leaders/streamers. On the other hand, negative leaders are well known to produce much more VHF and microwave radiation than positive leaders. Moreover, in previous works, microwave emissions from lightning leaders have been attributed to Bremsstrahlung process. The object of this work is to investigate if X-rays and RF microwave emissions share the same origin. We present simultaneous measurements of X-rays and microwaves in high voltage sparks and natural lightning. The instrumentation consists on a NaI(Tl) and LaBr3 scintillation detectors and two different receivers. One is fix tuned at 2.4 GHz with a bandwidth of 5.5 MHz. The second can be tuned at any frequency up to 18 GHz with different selectable bandwidths of 10 MHz, 40 MHz and 100 MHz. In the laboratory, results have shown that all the sparks presented microwave radiation before the breakdown of the gap, either X-rays were detected or not. In the cases where X-rays were identified, microwave emissions peaked at the same time (in the microsecond scale). We found that the power amplitudes of the microwave emissions are related to the applied voltage to the gap. In the same configuration, those cases where X-rays were detected microwave emissions presented higher power levels. The results suggest that in some part of the discharge electrons are very fast accelerated allowing, in some cases, to reach enought energy to produce X-rays. In the field, we have found similar results. On 13th of June of 2015 a bipolar cloud-to-ground flash struck 200 m close to the Eagle Nest instrumented tower (Spanish Pyrenees, 2536 m ASL). The flash presented four strokes and, in all of them, microwave

  6. The Fabrication of All-Solid-State Lithium-Ion Batteries via Spark Plasma Sintering

    Directory of Open Access Journals (Sweden)

    Xialu Wei

    2017-09-01

    Full Text Available Spark plasma sintering (SPS has been successfully used to produce all-solid-state lithium-ion batteries (ASSLibs. Both regular and functionally graded electrodes are implemented into novel three-layer and five-layer battery designs together with solid-state composite electrolyte. The electrical capacities and the conductivities of the SPS-processed ASSLibs are evaluated using the galvanostatic charge-discharge test. Experimental results have shown that, compared to the three-layer battery, the five-layer battery is able to improve energy and power densities. Scanning electron microscopy (SEM is employed to examine the microstructures of the batteries especially at the electrode–electrolyte interfaces. It reveals that the functionally graded structure can eliminate the delamination effect at the electrode–electrolyte interface and, therefore, retains better performance.

  7. Discharge Dialogue

    DEFF Research Database (Denmark)

    Horsbøl, Anders

    2012-01-01

    less attention has been given to medical patients, who are often elderly and suffer from multiple diseases. This paper addresses the latter issue with a case study of a local initiative to improve transition from hospital to home (care) for medical patients at a Danish hospital, in which a discharge......For several years, efforts have been made to strengthen collaboration between health professionals with different specializations and to improve patient transition from hospital to home (care). In the Danish health care system, these efforts have concentrated on cancer and heart diseases, whereas...

  8. Measurements of Radon Concentration in Yemen Using Spark Counter

    International Nuclear Information System (INIS)

    Arafa, W.; Abou-Leila, M.; Hafiz, M.E.; Al-Glal, N.

    2011-01-01

    Spark counter has been designed and realized and the optimum applied voltage was found to be 600 V. Excellent consistent agreements was observed between counted number of tracks by spark counter and reading by optical microscope. Radon concentration in some houses in Sana'a and Hodeidah cities in Yemen had been performed using LR-115 SSNTD and spark counter system. The average radon concentration in both cities was far lower the alert value. The results showed that radon concentration in the metropolitan area Sana'a was higher than that in Hodeidah city. Also, it was observed that old residential houses had higher levels of radon concentrations have compared to newly built houses in the metropolitan area Sana'a

  9. A miniature spark counter for public communication and education

    International Nuclear Information System (INIS)

    Mao, C.H.; Weng, P.S.

    1987-01-01

    The fabrication of a miniature spark counter for public communication and education using naturally occurring radon as a radioactive source without involving any man-made radioactivity is described. The battery-powered miniature spark counter weighs 2.07 kg with a volume of 4.844 x 10/sup -4/ m/sup 3/. The circuitry consists of seven major components: timer, high-voltage power supply, attenuator, noninverting amplifier, low-pass filter, one-shot generator, and counter. Cellulose nitrate films irradiated with alpha particles from radon emanating from soil were etched and counted. The visible sparks during counting are rather heuristic, which can be used to demonstrate naturally occurring radioactivity in classrooms or showplaces

  10. Spark plasma sintering of hydrothermally synthesized bismuth ferrite

    Directory of Open Access Journals (Sweden)

    Zorica Branković

    2016-12-01

    Full Text Available Bismuth ferrite, BiFeO3 (BFO, powder was synthesized by hydrothermal method from Bi(NO33·5 H2O and Fe(NO33·9 H2O as precursors. The synthesized powder was further sintered using spark plasma sintering (SPS. The sintering conditions were optimized in order to achieve high density, minimal amount of secondary phases and improved ferroelectric and magnetic properties. The optimal structure and properties were achieved after spark plasma sintering at 630 °C for 20 min, under uniaxial pressure of 90 MPa. The composition, microstructure, ferroelectric and magnetic properties of the SPS samples were characterized and compared to those of conventionally sintered ceramics obtained from the same powder. Although the samples sintered using conventional method showed slightly lower amount of secondary phases, the spark plasma sintered samples exhibited favourable microstructure and better ferroelectric properties.

  11. SparkClouds: visualizing trends in tag clouds.

    Science.gov (United States)

    Lee, Bongshin; Riche, Nathalie Henry; Karlson, Amy K; Carpendale, Sheelash

    2010-01-01

    Tag clouds have proliferated over the web over the last decade. They provide a visual summary of a collection of texts by visually depicting the tag frequency by font size. In use, tag clouds can evolve as the associated data source changes over time. Interesting discussions around tag clouds often include a series of tag clouds and consider how they evolve over time. However, since tag clouds do not explicitly represent trends or support comparisons, the cognitive demands placed on the person for perceiving trends in multiple tag clouds are high. In this paper, we introduce SparkClouds, which integrate sparklines into a tag cloud to convey trends between multiple tag clouds. We present results from a controlled study that compares SparkClouds with two traditional trend visualizations—multiple line graphs and stacked bar charts—as well as Parallel Tag Clouds. Results show that SparkClouds ability to show trends compares favourably to the alternative visualizations.

  12. Vacuum spark breakdown model based on exploding metal wire phenomena

    International Nuclear Information System (INIS)

    Haaland, J.

    1984-06-01

    Spark source mass spectra (SSMS) indicates that ions are extracted from an expanding and decaying plasma. The intensity distribution shows no dependance on vaporization properties of individual elements which indicates explosive vapour formation. This seems further to be a requirement for bridging a vacuum gap. A model including plasma ejection from a superheated anode spot by a process similar to that of an exploding metal wire is proposed. The appearance of hot plasma points in low inductance vacuum sparks can then be explained as exploding micro particles ejected from a final central anode spot. The phenomenological model is compared with available experimental results from literature, but no extensive quantification is attempted

  13. Theory and technique of spark source mass spectrometry

    International Nuclear Information System (INIS)

    Stefani, R.

    1968-01-01

    Trace analysis in solids by spark source mass spectrometry involves complicated phenomena: element ionization in spark and blacking of sensitive emulsion by focused ion beam. However the principal risk of selectivity lies in analyser system, which realizes double focusing only for a part of the ions. Therefore, each analyst has to known ionic optics of his apparatus, for ensuring the transmission of mean energetic ions, which are representative of sample composition. By a careful photometry of mass spectrum, good reproducibility can be obtained. Thereafter accuracy depends on the knowledge of sensitivity coefficients proper to this apparatus. (author) [fr

  14. Analysis of Plant Breeding on Hadoop and Spark

    Directory of Open Access Journals (Sweden)

    Shuangxi Chen

    2016-01-01

    Full Text Available Analysis of crop breeding technology is one of the important means of computer-assisted breeding techniques which have huge data, high dimensions, and a lot of unstructured data. We propose a crop breeding data analysis platform on Spark. The platform consists of Hadoop distributed file system (HDFS and cluster based on memory iterative components. With this cluster, we achieve crop breeding large data analysis tasks in parallel through API provided by Spark. By experiments and tests of Indica and Japonica rice traits, plant breeding analysis platform can significantly improve the breeding of big data analysis speed, reducing the workload of concurrent programming.

  15. A note on preserving the spark of a matrix

    Directory of Open Access Journals (Sweden)

    Marcin Skrzynski

    2015-05-01

    Full Text Available Let Mm× n(F be the vector space of all m× n matrices over a field F. In the case where m ≥ n, char (F ≠ 2 and F has at least five elements, we give a complete characterization of linear maps Φ : Mm× n(F → Mm× n(F such that spark(Φ (A = spark(A for any A ∈ Mm× n(F.

  16. Measurement of spark probability of GEM detector for CBM muon chamber (MUCH)

    CERN Document Server

    Biswas, S.; Frankenfeld, U.; Garabatos, C.; Hehner, J.; Kleipa, V.; Morhardt, T.; Schmidt, C.J.; Schmidt, H.R.; Wiechula, J.

    2015-11-11

    The stability of triple GEM detector setups in an environment of high energetic showers is studied. To this end the spark probability in a shower environment is compared to the spark probability in a pion beam.

  17. Experimental study of hard X-rays emitted from meter-scale positive discharges in air

    NARCIS (Netherlands)

    P.O. Kochkin (Pavlo); C.V. Nguyen; A. van Deursen (Arie); U. M. Ebert (Ute)

    2012-01-01

    textabstractWe investigate structure and evolution of long positive spark breakdown; and we study at which stage pulses of hard x-rays are emitted. Positive high-voltage pulses of standardized lightning impulse wave form of about 1 MV were applied to about 1 m of ambient air. The discharge evolution

  18. Lung surgery - discharge

    Science.gov (United States)

    ... Lung biopsy - discharge; Thoracoscopy - discharge; Video-assisted thoracoscopic surgery - discharge; VATS - discharge ... milk) for 2 weeks after video-assisted thoracoscopic surgery and 6 to 8 weeks after open surgery. ...

  19. Hysterectomy - vaginal - discharge

    Science.gov (United States)

    Vaginal hysterectomy - discharge; Laparoscopically assisted vaginal hysterectomy - discharge; LAVH - discharge ... you are unable to urinate. You have a discharge from your vagina that has a bad odor. You have bleeding ...

  20. Pediatric heart surgery - discharge

    Science.gov (United States)

    ... discharge; Heart valve surgery - children - discharge; Heart surgery - pediatric - discharge; Heart transplant - pediatric - discharge ... Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics . 20th ed. Philadelphia, PA: Elsevier; 2016:chap 434. ...

  1. Hip replacement - discharge

    Science.gov (United States)

    ... discharge; Total hip replacement - discharge; Hip hemiarthroplasty - discharge; Osteoarthritis - hip replacement discharge ... such as downhill skiing or contact sports like football and soccer. But you should be able to ...

  2. Effect of the anode material on the X-ray spectrum of micropinch discharge plasma

    Science.gov (United States)

    Grigoryeva, I. G.; Savjolov, A. S.; Salakhutdinov, G. Kh.

    2017-07-01

    The effect of the elemental composition of the anode material on the parameters and X-ray spectrum of micropinch discharge plasma have been studied using a low-inductance vacuum spark device. It is shown that the plasma electron temperature T e and intensity of hard X-ray emission increase with increasing nuclear charge number Z of the anode material of the discharge system.

  3. [Early thrombogenic problems in the sparks-prothesis (author's transl)].

    Science.gov (United States)

    Kleine, H O; Stockmann, U

    1975-04-01

    Some patients with Sparks arterial bypass graft show just during the operation a thrombosis in the prothesis. After the rubber rod has been pulled off, thrombogenic substances can be washed out of the prothesis-lumen. They shorten the clotting time of the patients' venous blood. 1000 ml 0.0% NaCl prevent this early thrombosis in the arterial bypass graft.

  4. knock characteristics analysis of a supercharged spark ignition

    African Journals Online (AJOL)

    user

    KNOCK CHARACTERISTICS ANALYSIS OF SUPERCHARGED SPARK IGNITION ENGINE USING THREE GRADES OF FUELS,. D. C. Uguru-Okorie .... pressure with the engine crank angle. The data acquisition system was controlled by a LabView script written which acquired pressure data at a sampling rate of 200 kHz.

  5. Utilization of Alcohol Fuel in Spark Ignition and Diesel Engines.

    Science.gov (United States)

    Berndt, Don; Stengel, Ron

    These five units comprise a course intended to prepare and train students to conduct alcohol fuel utilization seminars in spark ignition and diesel engines. Introductory materials include objectives and a list of instructor requirements. The first four units cover these topics: ethanol as an alternative fuel (technical and economic advantages,…

  6. SparkText: Biomedical Text Mining on Big Data Framework.

    Directory of Open Access Journals (Sweden)

    Zhan Ye

    Full Text Available Many new biomedical research articles are published every day, accumulating rich information, such as genetic variants, genes, diseases, and treatments. Rapid yet accurate text mining on large-scale scientific literature can discover novel knowledge to better understand human diseases and to improve the quality of disease diagnosis, prevention, and treatment.In this study, we designed and developed an efficient text mining framework called SparkText on a Big Data infrastructure, which is composed of Apache Spark data streaming and machine learning methods, combined with a Cassandra NoSQL database. To demonstrate its performance for classifying cancer types, we extracted information (e.g., breast, prostate, and lung cancers from tens of thousands of articles downloaded from PubMed, and then employed Naïve Bayes, Support Vector Machine (SVM, and Logistic Regression to build prediction models to mine the articles. The accuracy of predicting a cancer type by SVM using the 29,437 full-text articles was 93.81%. While competing text-mining tools took more than 11 hours, SparkText mined the dataset in approximately 6 minutes.This study demonstrates the potential for mining large-scale scientific articles on a Big Data infrastructure, with real-time update from new articles published daily. SparkText can be extended to other areas of biomedical research.

  7. SparkText: Biomedical Text Mining on Big Data Framework.

    Science.gov (United States)

    Ye, Zhan; Tafti, Ahmad P; He, Karen Y; Wang, Kai; He, Max M

    Many new biomedical research articles are published every day, accumulating rich information, such as genetic variants, genes, diseases, and treatments. Rapid yet accurate text mining on large-scale scientific literature can discover novel knowledge to better understand human diseases and to improve the quality of disease diagnosis, prevention, and treatment. In this study, we designed and developed an efficient text mining framework called SparkText on a Big Data infrastructure, which is composed of Apache Spark data streaming and machine learning methods, combined with a Cassandra NoSQL database. To demonstrate its performance for classifying cancer types, we extracted information (e.g., breast, prostate, and lung cancers) from tens of thousands of articles downloaded from PubMed, and then employed Naïve Bayes, Support Vector Machine (SVM), and Logistic Regression to build prediction models to mine the articles. The accuracy of predicting a cancer type by SVM using the 29,437 full-text articles was 93.81%. While competing text-mining tools took more than 11 hours, SparkText mined the dataset in approximately 6 minutes. This study demonstrates the potential for mining large-scale scientific articles on a Big Data infrastructure, with real-time update from new articles published daily. SparkText can be extended to other areas of biomedical research.

  8. Assembly of optical spark chambers for the experiment Nue

    CERN Multimedia

    1974-01-01

    To continue the research on neutral currents after their discovery in Gargamelle in 1973, the Aachen-Padua Collaboration set up in the neutrino beam of the PS South-East Area, behind Gargamelle, an assembly of 150 optical spark chambers, 2x2 m2 extending over 8 m (experiment T230, Nue). Hans Reithler stands on the right.

  9. Joining of β-SiC by spark plasma sintering

    Czech Academy of Sciences Publication Activity Database

    Grasso, S.; Tatarko, Peter; Rizzo, S.; Porwal, H.; Hu, Ch.; Katoh, Y.; Salvo, M.; Reece, M. J.; Ferraris, M.

    2014-01-01

    Roč. 34, č. 7 (2014), s. 1681-1686 ISSN 0955-2219 EU Projects: European Commission(XE) 264526 - GLACERCO Institutional support: RVO:68081723 Keywords : β-SiC * joining * Spark plasma sintering Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 2.947, year: 2014

  10. 46 CFR 30.10-63 - Spark arrester-TB/ALL.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Spark arrester-TB/ALL. 30.10-63 Section 30.10-63 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Definitions § 30.10-63 Spark arrester—TB/ALL. The term spark arrester means any device, assembly, or method of a...

  11. Effect of pulse energy on the dynamic development of spark-plasma-jet driven by nanosecond high-voltage pulse

    Science.gov (United States)

    Tie, W.; Zhang, Y.; Meng, C.; Zhang, Q.; Yan, Z.; He, P.

    2018-01-01

    We investigated the spatial-temporal dynamics characteristics of the spark-plasma-jet (SPJ) in the nitrogen of 0.1 MPa at different pulse energies by fast photography and optical emission spectrum. The spark plasma generated by spark discharge can be rapidly sprayed out of the micro-incentive cavity within several tens nanoseconds under the action of electric field, and the spraying delay time reduces gradually with increase of pulse energy. The outlet velocity of SPJ reaches up to 104 m s‑1. After that, the propulsion velocity decreases dramatically by 1 or 2 orders of magnitude at 2 μs. These two striking features were observed during the SPJ propulsion period. Firstly, there are two propulsion modes including ‘plasma column’ and ‘plasma bullet’ appearing in the development of SPJ successively. The conversion from plasma column to plasma bullet is slowed down with the increase of discharge current duration. Secondly, the inner form of SPJ exhibits the ‘halo’, ‘core-halo’ and ‘tree’ patterns respectively at the pulse energies of 1.6 J, 32 J and 160 J. Furthermore, the distribution morphology of SPJ obviously has flow field features. In order to accurately estimate the spatial-temporal distribution of electron parameters by optical emission spectroscopy diagnosis, the electron temperature was calculated by the Boltzmann plot method and continuum radiation, respectively, and the electron density was calculated by the Saha equation and Stark broadening respectively. The results show that the electron temperature and electron density of SPJ are 1.7 eV ∼ 2.9 eV and 8.5 × 1016/cm3 ∼ 1.0 × 1018/cm3 respectively in different conditions. These results provide some fundamental knowledge about the dynamic development of SPJ.

  12. INFLUENCE OF ELECTRIC SPARK ON HARDNESS OF CARBON STEEL

    Directory of Open Access Journals (Sweden)

    I. O. Vakulenko

    2014-03-01

    Full Text Available Purpose. The purpose of work is an estimation of influence of an electric spark treatment on the state of mouldable superficial coverage of carbon steel. Methodology. The steel of fragment of railway wheel rim served as material for research with chemical composition 0.65% С, 0.67% Mn, 0.3% Si, 0.027% P, 0.028% S. Structural researches were conducted with the use of light microscopy and methods of quantitative metallography. The structural state of the probed steel corresponded to the state after hot plastic deformation. The analysis of hardness distribution in the micro volumes of cathode metal was carried out with the use of microhardness tester of type of PMT-3. An electric spark treatment of carbon steel surface was executed with the use of equipment type of EFI-25M. Findings. After electric spark treatment of specimen surface from carbon steel the forming of multi-layered coverage was observed. The analysis of microstructure found out the existence of high-quality distinctions in the internal structure of coverage metal, depending on the probed area. The results obtained in the process are confirmed by the well-known theses, that forming of superficial coverage according to technology of electric spark is determined by the terms of transfer and crystallization of metal. The gradient of structures on the coverage thickness largely depends on development of structural transformation processes similar to the thermal character influence. Originality. As a result of electric spark treatment on the condition of identical metal of anode and cathode, the first formed layer of coverage corresponds to the monophase state according to external signs. In the volume of coverage metal, the appearance of carbide phase particles is accompanied by the decrease of microhardness values. Practical value. Forming of multi-layered superficial coverage during electric spark treatment is accompanied by the origin of structure gradient on a thickness. The effect

  13. Time-resolved processes in a pulsed electrical discharge in water generated with shock wave assistance in a plate-to-plate configuration

    Czech Academy of Sciences Publication Activity Database

    Stelmashuk, Vitaliy

    2014-01-01

    Roč. 47, č. 49 (2014), s. 495204-495204 ISSN 0022-3727 Institutional support: RVO:61389021 Keywords : underwater discharge * streamers * spark * cavitation bubble * shock wave Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.721, year: 2014 http://iopscience.iop.org/0022-3727/47/49/495204/pdf/0022-3727_47_49_495204.pdf

  14. A small size 1-3 atm pulsed CO2 laser with series-connected spark gaps ultraviolet preionization.

    Science.gov (United States)

    Silakhori, K; Jelvani, S; Ghanavati, F; Sajad, B; Talebi, M; Sadr, M R

    2014-01-01

    A small size pulsed CO2 laser with rounded edge flat profiled electrodes and variable gas pressure in 1-3 atm range has been constructed and characterized. The perionization system consists of a pair of 16 series-connected spark gaps located along either side of the main electrodes by which, the number of required preionization capacitors is reduced to 4. Sharpening of the main discharge has been performed using a 300 pF peaking capacitor. A maximum energy of 160 mJ/pulse was obtained for CO2:N2:He≡1:1:8 gas mixture and 33 kV discharge voltage. By increasing the laser gas pressure in 1-3 atm range, the duration of spike and tail parts of the laser pulses have been reduced from 110 ns and 4 μs to 37 ns and 1 μs, respectively.

  15. Erosion on spark plug electrodes; Funkenerosion an Zuendkerzenelektroden

    Energy Technology Data Exchange (ETDEWEB)

    Rager, J.

    2006-07-01

    Durability of spark plugs is mainly determined by spark gap widening, caused by electrode wear. Knowledge about the erosion mechanisms of spark plug materials is of fundamental interest for the development of materials with a high resistance against electrode erosion. It is therefore crucial to identify those parameters which significantly influence the erosion behaviour of a material. In this work, a reliable and reproducible testing method is presented which produces and characterizes electrode wear under well-defined conditions and which is capable of altering parameters specifically. Endurance tests were carried out to study the dependence of the wear behaviour of pure nickel and platinum on the electrode temperature, gas, electrode gap, electrode diameter, atmospheric pressure, and partial pressure of oxygen. It was shown that erosion under nitrogen is negligible, irrespective of the material. This disproves all common mechanism discussed in the literature explaining material loss of spark plug electrodes. Based on this observation and the variation of the mentioned parameters a new erosion model was deduced. This relies on an oxidation of the electrode material and describes the erosion of nickel and platinum separately. For nickel, electrode wear is caused by the removal of an oxide layer by the spark. In the case of platinum, material loss occurs due to the plasma-assisted formation and subsequent evaporation of volatile oxides in the cathode spot. On the basis of this mechanism a new composite material was developed whose erosion resistance is superior to pure platinum. Oxidation resistant metal oxide particles were added to a platinum matrix, thus leading to a higher erosion resistance of the composite. However, this can be decreased by a side reaction, the separation of oxygen from the metal oxides, which effectively assists the oxidation of the matrix. This reaction can be suppressed by using highly stable oxides, characterized by a large negative Gibbs

  16. Electrode erosion properties of gas spark switches for fast linear transformer drivers

    Science.gov (United States)

    Li, Xiaoang; Pei, Zhehao; Zhang, Yuzhao; Liu, Xuandong; Li, Yongdong; Zhang, Qiaogen

    2017-12-01

    Fast linear transformer drivers (FLTDs) are a popular and potential route for high-power devices employing multiple "bricks" in series and parallel, but they put extremely stringent demands on gas switches. Electrode erosion of FLTD gas switches is a restrictive and unavoidable factor that degrades performance and limits stability. In this paper, we systematically investigated the electrode erosion characteristics of a three-electrode field distortion gas switch under the typical working conditions of FLTD switches, and the discharge current was 7-46 kA with 46-300 ns rise time. A high speed frame camera and a spectrograph were used to capture the expansion process and the spectral emission of the spark channel was used to estimate the current density and the spark temperature, and then the energy fluxes and the external forces on the electrode surface were calculated. A tens of kilo-ampere nanosecond pulse could generate a 1011 W/m2 energy flux injection and 1.3-3.5 MPa external pressure on the electrode surface, resulting in a millimeter-sized erosion crater with the maximum peak height Rz reaching 100 μm magnitude. According to the morphological images by a laser scanning confocal microscope, the erosion crater of a FLTD switch contained three kinds of local morphologies, namely a center boiling region, an overflow region and a sputtering region. In addition, the crater size, the surface roughness, and the mass loss were highly dependent on the current amplitude and the transferred charge. We also observed Morphology Type I and Type II, respectively, with different pulse parameters, which had an obvious influence on surface roughness and mass loss. Finally, the quantitative relationship between the electrode mass loss and the pulse parameter was clarified. The transferred charge and the current amplitude were proved to be the main factors determining the electrode mass loss of a FLTD switch, and a least squares fitting expression for mass loss was also obtained.

  17. Microstructure and property evolution of isotropic and anisotropic NdFeB magnets fabricated from nanocrystalline ribbons by spark plasma sintering and hot deformation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Z W; Huang, H Y; Yu, H Y; Zhong, X C; Zeng, D C [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Gao, X X; Zhu, J, E-mail: zwliu@scut.edu.cn [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)

    2011-01-19

    Isotropic and anisotropic NdFeB magnets were synthesized by spark plasma sintering (SPS) and SPS+HD (hot deformation), respectively, using melt-spun ribbons as the starting materials. Spark plasma sintered magnets sintered at low temperatures (<700 {sup 0}C) almost maintained the uniform fine grain structure inherited from rapid quenching. At higher temperatures, due to the local high-temperature field caused by the spark plasma discharge, the grain growth occurred at the initial particle surfaces and the coarse grain zones formed in the vicinity of the particle boundaries. Since the interior of the particles maintained the fine grain structure, a distinct two-zone structure was formed in the spark plasma sintered magnets. The SPS temperature and pressure have important effects on the widths of coarse and fine grain zones, as well as the grain sizes in two zones. The changes in grain structure led to variations in the magnetic properties. By employing low SPS temperature and high pressure, high-density magnets with negligible coarse grain zone and an excellent combination of magnetic properties can be obtained. An anisotropic magnet with a maximum energy product of {approx}30 MG Oe was produced by the SPS+HD process. HD at 750 {sup 0}C did not lead to obvious grain growth and the two-zone structure still existed in the hot deformed magnets. Intergranular exchange coupling was demonstrated in the spark plasma sintered magnets and was enhanced by the HD process, which reduced the coercivity. Good temperature stability was manifested by low temperature coefficients of remanence and coercivity. The results indicated that nanocrystalline NdFeB magnets without significant grain growth and with excellent properties could be obtained by SPS and HD processes.

  18. Ignition of dust clouds by sparks and heated surfaces; Inflammation des nuages de poussieres par des etincelles et des surfaces chauffees

    Energy Technology Data Exchange (ETDEWEB)

    Proust, C.; Boudalaa, M. [Institut National de l' Environnement Industriel et des Risques, 60 - Verneuil en Halatte (INERIS) (France)

    2001-07-01

    The three types of ignition sources described in this article are the sources of mechanical origin, the heated surfaces and the sparks of electrostatic origin. These 3 categories should be at the origin of 75% of the referenced dust explosions. The approach retained is mainly experimental. Hot spots are produced by the impact of a laser beam (Nd-YAG) on a target located inside the cloud. For relatively long delays of ignition (1 to 2 mn), the characteristic ignition parameter is the thermal power supplied by the target to the mixture, at least when the hot-spot size is small enough (less than 2 or 3 mm). Above this size, the ignition parameter would rather be a critical temperature of the hot spot which can be linked to the 'standard' ignition temperature of the cloud. For electrostatic sparks, measurements of current-voltage characteristics have been performed with some measurements of dimensions. Most possible types have been examined, like the discharges between conductive materials (A), between a conductive material and an insulating material (B), and between a conductive material and an insulating material lined with a conductor connected to the ground (C). It appears that the most powerful sparks (several joules) encountered in the industrial environment are those of type A and C. Measurements have shown that the efficiency of the conversion of the energy stored on the surface of the material into electrical energy inside the spark is very high. Finally, a first approach of the examination of the ignition risk has been tempted with a hot spot created during a lapse of time compatible with a mechanical impact. This leads to an ignition criterion in the form of energy. This energy remains at least two scales of size greater than the minimum spark ignition energy. This difference should come from the absorption of heat by solid materials. (J.S.)

  19. Supression of laser breakdown by pulsed nonequilibrium ns discharge

    Science.gov (United States)

    Starikovskiy, A. Y.; Semenov, I. E.; Shneider, M. N.

    2016-10-01

    The avalanche ionization induced by infrared laser pulses was investigated in a pre-ionized argon gas. Pre-ionization was created by a high-voltage pulsed nanosecond discharge developed in the form of a fast ionization wave. Then, behind the front of ionization wave additional avalanche ionization was initiated by the focused Nd-YAG laser pulse. It was shown that the gas pre-ionization inhibits the laser spark generation. It was demonstrated that the suppression of laser spark development in the case of strong gas pre-ionization is because of fast electron energy transfer from the laser beam focal region. The main mechanism of this energy transfer is free electrons diffusion.

  20. High-speed micro-electro-discharge machining.

    Energy Technology Data Exchange (ETDEWEB)

    Chandrasekar, Srinivasan Dr. (.School of Industrial Engineering, West Lafayette, IN); Moylan, Shawn P. (School of Industrial Engineering, West Lafayette, IN); Benavides, Gilbert Lawrence

    2005-09-01

    When two electrodes are in close proximity in a dielectric liquid, application of a voltage pulse can produce a spark discharge between them, resulting in a small amount of material removal from both electrodes. Pulsed application of the voltage at discharge energies in the range of micro-Joules results in the continuous material removal process known as micro-electro-discharge machining (micro-EDM). Spark erosion by micro-EDM provides significant opportunities for producing small features and micro-components such as nozzle holes, slots, shafts and gears in virtually any conductive material. If the speed and precision of micro-EDM processes can be significantly enhanced, then they have the potential to be used for a wide variety of micro-machining applications including fabrication of microelectromechanical system (MEMS) components. Toward this end, a better understanding of the impacts the various machining parameters have on material removal has been established through a single discharge study of micro-EDM and a parametric study of small hole making by micro-EDM. The main avenues for improving the speed and efficiency of the micro-EDM process are in the areas of more controlled pulse generation in the power supply and more controlled positioning of the tool electrode during the machining process. Further investigation of the micro-EDM process in three dimensions leads to important design rules, specifically the smallest feature size attainable by the process.

  1. Practical internal combustion engine laser spark plug development

    Science.gov (United States)

    Myers, Michael J.; Myers, John D.; Guo, Baoping; Yang, Chengxin; Hardy, Christopher R.

    2007-09-01

    Fundamental studies on laser ignition have been performed by the US Department of Energy under ARES (Advanced Reciprocating Engines Systems) and by the California Energy Commission under ARICE (Advanced Reciprocating Internal Combustion Engine). These and other works have reported considerable increases in fuel efficiencies along with substantial reductions in green-house gas emissions when employing laser spark ignition. Practical commercial applications of this technology require low cost high peak power lasers. The lasers must be small, rugged and able to provide stable laser beam output operation under adverse mechanical and environmental conditions. New DPSS (Diode Pumped Solid State) lasers appear to meet these requirements. In this work we provide an evaluation of HESP (High Efficiency Side Pumped) DPSS laser design and performance with regard to its application as a practical laser spark plug for use in internal combustion engines.

  2. 100 kV reliable accurately-synchronized spark gap

    International Nuclear Information System (INIS)

    Bosamykin, V.S.; Gerasimov, A.I.; Zenkov, D.I.

    1987-01-01

    100 kV three-electrode spark gap filled with 40% SF 6 +60% N 2 mixture under the pressure of ∼ 1 MPa, which has spread Δt ≤ ± 5 ns of operating time delay in the range of 10 4 triggerings and commutation energy of 2.5 kJ, providing electric strength is 100%, is described; at 10 kJ Δt is less than ± 10 ns for 10 3 triggerings. Parallel connection of 16 groups, each consisting of 5 spark gaps with series connection, electric strength being 100%, in the pulse charging unit of Arkadiev-Marx generator being in operation for several years manifested their high efficiency; mutual group spread is ≤ ± 15 ns

  3. Large area spark counters with fine time and position resolution

    International Nuclear Information System (INIS)

    Ogawa, A.; Atwood, W.B.; Fujiwara, N.; Pestov, Yu.N.; Sugahara, R.

    1983-10-01

    Spark counters trace their history back over three decades but have been used in only a limited number of experiments. The key properties of these devices include their capability of precision timing (at the sub 100 ps level) and of measuring the position of the charged particle to high accuracy. At SLAC we have undertaken a program to develop these devices for use in high energy physics experiments involving large detectors. A spark counter of size 1.2 m x 0.1 m has been constructed and has been operating continuously in our test setup for several months. In this talk I will discuss some details of its construction and its properties as a particle detector. 14 references

  4. DC discharges in atmospheric air for bio-decontamination - spectroscopic methods for mechanism identification

    Science.gov (United States)

    Machala, Z.; Jedlovský, I.; Chládeková, L.; Pongrác, B.; Giertl, D.; Janda, M.; Ikurová, L. Å.; Polčic, P.

    2009-08-01

    Three types of DC electrical discharges in atmospheric air (streamer corona, transient spark and glow discharge) were tested for bio-decontamination of bacteria and yeasts in water solution, and spores on surfaces. Static vs. flowing treatment of contaminated water were compared, in the latter the flowing water either covered the grounded electrode or passed through the high voltage needle electrode. The bacteria were killed most efficiently in the flowing regime by transient spark. Streamer corona was efficient when the treated medium flew through the active corona region. The spores on plastic foil and paper surfaces were successfully inactivated by negative corona. The microbes were handled and their population evaluated by standard microbiology cultivation procedures. The emission spectroscopy of the discharges and TBARS (thiobarbituric acid reactive substances) absorption spectrometric detection of the products of lipid peroxidation of bacterial cell membranes indicated a major role of radicals and reactive oxygen species among the bio-decontamination mechanisms.

  5. Particular bi-fuel application of spark ignition engines

    Science.gov (United States)

    Raţiu, S.; Alexa, V.; Kiss, I.

    2016-02-01

    This paper presents a comparative test concerning the operation of a spark-ignition engine, make: Dacia 1300, model: 810.99, fuelled alternatively with gasoline and LPG (Liquefied Petroleum Gas). The tests carried out show, on the one hand, the maintenance of power and torque performances in both engine fuelling cases, for all the engine operation regimes, and, on the other hand, a considerable decrease in CO and HC emissions when using poor mixtures related to LPG fuelling.

  6. The Use of Spark Ignition Engine in Domestic Cogeneration

    Directory of Open Access Journals (Sweden)

    Feiza Memet

    2009-10-01

    Full Text Available Cogeneration plants are strongly sustained by EU energy policies, one of the best beneficiary of this technology being residential buildings. This paper focus on spark ignition engine as a cogeneration application in order to supply energy for domestic consumers. Are considered two aspects of this solution: the energetic aspect and the environmental one. The energetic aspect deals with the energetic ratios, while the environmental aspect refers to the nitrogen oxide and carbon monoxide emissions.

  7. The time response function of spark counters and RPCs

    International Nuclear Information System (INIS)

    Gobbi, A.; Mangiarotti, A.

    2003-01-01

    The fluctuation theory for the avalanche growth with and without space charge effects is briefly summarized and compared to a broad field of applications. These include spark counters as well as timing and trigger RPCs operated in avalanche mode. A large domain in electrical field strength, pressure, gap size and gas mixture type is covered. A reasonable agreement with the experiment is observed, giving confidence on the validity of both assumptions and treatment of the theory

  8. Loits skandaalitses gaalal. Sparks Rabarockil. Pärimusmuusika Ait

    Index Scriptorium Estoniae

    2008-01-01

    Pärnu Kontserdimajas Eesti muusikaauhindade galal üle astunud rockansambel Loits röövis koostöös kultuskirjaniku Sven Kivisildnikuga aasta metal/punk-artisti auhinna, mis pidi minema industrial-metal-artistile Finish Me Off. Ameerika bänd Sparks 14. juunil Järvakandis Rabarockil. Viljandis Tasuja pst.6 avati Eesti Pärimusmuusika Keskuse uus kodu - Pärimusmuusika Ait

  9. High repetition rate burst-mode spark gap

    International Nuclear Information System (INIS)

    Faltens, A.; Reginato, L.; Hester, R.; Chesterman, A.; Cook, E.; Yokota, T.; Dexter, W.

    1978-01-01

    Results are presented on the design and testing of a pressurized gas blown spark gap switch capable of high repetition rates in a burst mode of operation. The switch parameters which have been achieved are as follows: 220-kV, 42-kA, a five pulse burst at 1-kHz, 12-ns risetime, 2-ns jitter at a pulse width of 50-ns

  10. CMS Analysis and Data Reduction with Apache Spark

    Energy Technology Data Exchange (ETDEWEB)

    Gutsche, Oliver [Fermilab; Canali, Luca [CERN; Cremer, Illia [Magnetic Corp., Waltham; Cremonesi, Matteo [Fermilab; Elmer, Peter [Princeton U.; Fisk, Ian [Flatiron Inst., New York; Girone, Maria [CERN; Jayatilaka, Bo [Fermilab; Kowalkowski, Jim [Fermilab; Khristenko, Viktor [CERN; Motesnitsalis, Evangelos [CERN; Pivarski, Jim [Princeton U.; Sehrish, Saba [Fermilab; Surdy, Kacper [CERN; Svyatkovskiy, Alexey [Princeton U.

    2017-10-31

    Experimental Particle Physics has been at the forefront of analyzing the world's largest datasets for decades. The HEP community was among the first to develop suitable software and computing tools for this task. In recent times, new toolkits and systems for distributed data processing, collectively called "Big Data" technologies have emerged from industry and open source projects to support the analysis of Petabyte and Exabyte datasets in industry. While the principles of data analysis in HEP have not changed (filtering and transforming experiment-specific data formats), these new technologies use different approaches and tools, promising a fresh look at analysis of very large datasets that could potentially reduce the time-to-physics with increased interactivity. Moreover these new tools are typically actively developed by large communities, often profiting of industry resources, and under open source licensing. These factors result in a boost for adoption and maturity of the tools and for the communities supporting them, at the same time helping in reducing the cost of ownership for the end-users. In this talk, we are presenting studies of using Apache Spark for end user data analysis. We are studying the HEP analysis workflow separated into two thrusts: the reduction of centrally produced experiment datasets and the end-analysis up to the publication plot. Studying the first thrust, CMS is working together with CERN openlab and Intel on the CMS Big Data Reduction Facility. The goal is to reduce 1 PB of official CMS data to 1 TB of ntuple output for analysis. We are presenting the progress of this 2-year project with first results of scaling up Spark-based HEP analysis. Studying the second thrust, we are presenting studies on using Apache Spark for a CMS Dark Matter physics search, comparing Spark's feasibility, usability and performance to the ROOT-based analysis.

  11. NEUTRON IRRADIATION EFFECTS ON SPARK PLASMA SINTERED BORON CARBIDE

    OpenAIRE

    Buyuk, Bulent; Cengiz, Meral; Tugrul, A. Beril

    2015-01-01

    In this study, spark plasma sintered boron carbide (B4C) was examined against neutrons. The specimens were irradiated by reactor neutrons (include both thermal and fast neutrons) up to fluence of 1.37x1021n m-2. Thermal and fast neutrons cause swelling by different interactions with boron (10B) atoms in the related materials. X-Ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images were investigated for initial and irradiated samples. In addition, lattice parameters and ...

  12. effect of gasket of varying thickness on spark ignition engines

    African Journals Online (AJOL)

    DJFLEX

    In the study of Toyota, In-line, 4 cylinders, spark ignition engine using gaskets of varying thicknesses. (1.75mm, 3.5mm, 5.25mm, 7mm and 8.75mm) between the cylinder head and the engine block, the performance characteristics of the engine was investigated via the effect of engine speed on brake power, brake thermal ...

  13. Ankle replacement - discharge

    Science.gov (United States)

    ... total - discharge; Total ankle arthroplasty - discharge; Endoprosthetic ankle replacement - discharge; Osteoarthritis - ankle ... You had an ankle replacement. Your surgeon removed and reshaped ... an artificial ankle joint. You received pain medicine and were ...

  14. Tennis elbow surgery - discharge

    Science.gov (United States)

    Lateral epicondylitis surgery - discharge; Lateral tendinosis surgery - discharge; Lateral tennis elbow surgery - discharge ... Soon after surgery, severe pain will decrease, but you may have mild soreness for 3 to 6 months.

  15. Knee joint replacement - discharge

    Science.gov (United States)

    ... Knee replacement - total - discharge; Tricompartmental knee replacement - discharge; Osteoarthritis - knee replacement discharge ... such as downhill skiing or contact sports like football and soccer. But, you should be able to ...

  16. Research on retailer data clustering algorithm based on Spark

    Science.gov (United States)

    Huang, Qiuman; Zhou, Feng

    2017-03-01

    Big data analysis is a hot topic in the IT field now. Spark is a high-reliability and high-performance distributed parallel computing framework for big data sets. K-means algorithm is one of the classical partition methods in clustering algorithm. In this paper, we study the k-means clustering algorithm on Spark. Firstly, the principle of the algorithm is analyzed, and then the clustering analysis is carried out on the supermarket customers through the experiment to find out the different shopping patterns. At the same time, this paper proposes the parallelization of k-means algorithm and the distributed computing framework of Spark, and gives the concrete design scheme and implementation scheme. This paper uses the two-year sales data of a supermarket to validate the proposed clustering algorithm and achieve the goal of subdividing customers, and then analyze the clustering results to help enterprises to take different marketing strategies for different customer groups to improve sales performance.

  17. First SPARK-STREAM Workshop on livelihoods and languages, Bangkok, Thailand, 9-11 April 2003. Livelihoods and languages: a SPARK-STREAM learning and communications process

    OpenAIRE

    2003-01-01

    The First SPARK-STREAM Workshop on Livelihoods and Languages took place in Bangkok, Thailand, from 9-11 April 2003. It was the first activity in a SPARK-STREAM learning and communications process around livelihoods and languages. (PDF contains 53 pages)

  18. Spark Ignition Characteristics of a LO2/LCH4 Engine at Altitude Conditions

    Science.gov (United States)

    Kleinhenz, Julie; Sarmiento, Charles; Marshall, William

    2012-01-01

    The use of non-toxic propellants in future exploration vehicles would enable safer, more cost effective mission scenarios. One promising "green" alternative to existing hypergols is liquid methane/liquid oxygen. To demonstrate performance and prove feasibility of this propellant combination, a 100lbf LO2/LCH4 engine was developed and tested under the NASA Propulsion and Cryogenic Advanced Development (PCAD) project. Since high ignition energy is a perceived drawback of this propellant combination, a test program was performed to explore ignition performance and reliability versus delivered spark energy. The sensitivity of ignition to spark timing and repetition rate was also examined. Three different exciter units were used with the engine's augmented (torch) igniter. Propellant temperature was also varied within the liquid range. Captured waveforms indicated spark behavior in hot fire conditions was inconsistent compared to the well-behaved dry sparks (in quiescent, room air). The escalating pressure and flow environment increases spark impedance and may at some point compromise an exciter.s ability to deliver a spark. Reduced spark energies of these sparks result in more erratic ignitions and adversely affect ignition probability. The timing of the sparks relative to the pressure/flow conditions also impacted the probability of ignition. Sparks occurring early in the flow could trigger ignition with energies as low as 1-6mJ, though multiple, similarly timed sparks of 55-75mJ were required for reliable ignition. An optimum time interval for spark application and ignition coincided with propellant introduction to the igniter and engine. Shifts of ignition timing were manifested by changes in the characteristics of the resulting ignition.

  19. Spark Ignition Characteristics of a L02/LCH4 Engine at Altitude Conditions

    Science.gov (United States)

    Kleinhenz, Julie; Sarmiento, Charles; Marshall, William

    2012-01-01

    The use of non-toxic propellants in future exploration vehicles would enable safer, more cost effective mission scenarios. One promising "green" alternative to existing hypergols is liquid methane/liquid oxygen. To demonstrate performance and prove feasibility of this propellant combination, a 100lbf LO2/LCH4 engine was developed and tested under the NASA Propulsion and Cryogenic Advanced Development (PCAD) project. Since high ignition energy is a perceived drawback of this propellant combination, a test program was performed to explore ignition performance and reliability versus delivered spark energy. The sensitivity of ignition to spark timing and repetition rate was also examined. Three different exciter units were used with the engine s augmented (torch) igniter. Propellant temperature was also varied within the liquid range. Captured waveforms indicated spark behavior in hot fire conditions was inconsistent compared to the well-behaved dry sparks (in quiescent, room air). The escalating pressure and flow environment increases spark impedance and may at some point compromise an exciter s ability to deliver a spark. Reduced spark energies of these sparks result in more erratic ignitions and adversely affect ignition probability. The timing of the sparks relative to the pressure/flow conditions also impacted the probability of ignition. Sparks occurring early in the flow could trigger ignition with energies as low as 1-6mJ, though multiple, similarly timed sparks of 55-75mJ were required for reliable ignition. An optimum time interval for spark application and ignition coincided with propellant introduction to the igniter and engine. Shifts of ignition timing were manifested by changes in the characteristics of the resulting ignition.

  20. The spark-plug imitates the lightning; La bougie s'inspire de la foudre

    Energy Technology Data Exchange (ETDEWEB)

    Beaufils, Ph.

    2003-12-01

    The researchers-engineers of Renault company, the French car maker, have developed a spark-plug capable to generate a spark 3 to 6 times more longer than with a classical plug. The geometry of the different parts of the plug keeps the spark (electron avalanche) along the dielectric ceramic insulator between the central electrode and the socket. With this plug, the ignition of heterogenous mixtures is more efficient and the voltage necessary to generate the spark remains below 20000 V (with respect to 40000 V with a classical plug). Short paper. (J.S.)

  1. Search for an optimum time response of spark counters

    International Nuclear Information System (INIS)

    Devismes, A.; Finck, Ch.; Kress, T.; Gobbi, A.; Eschke, J.; Herrmann, N.; Hildenbrand, K.D.; Koczon, P.; Petrovici, M.

    2002-01-01

    A spark counter of the type developed by Pestov has been tested with the aim of searching for an optimum time response function, changing voltage, content of noble and quencher gases, pressure and energy-loss. Replacing the usual argon by neon has brought an improvement of the resolution and a significant reduction of tails in the time response function. It has been proven that a counter as long as 90 cm can deliver, using neon gas mixture, a time resolution σ<60 ps with about 1% absolute tail and an efficiency of about 90%

  2. A Scalable Smart Meter Data Generator Using Spark

    DEFF Research Database (Denmark)

    Iftikhar, Nadeem; Liu, Xiufeng; Danalachi, Sergiu

    2017-01-01

    Today, smart meters are being used worldwide. As a matter of fact smart meters produce large volumes of data. Thus, it is important for smart meter data management and analytics systems to process petabytes of data. Benchmarking and testing of these systems require scalable data, however, it can...... be challenging to get large data sets due to privacy and/or data protection regulations. This paper presents a scalable smart meter data generator using Spark that can generate realistic data sets. The proposed data generator is based on a supervised machine learning method that can generate data of any size...

  3. Spark plasma sintering of commercial and development titanium alloy powders

    OpenAIRE

    Weston, N.S.; Derguti, F.; Tudball, A.; Jackson, M.

    2015-01-01

    Emerging lower cost titanium metal powder produced via an electrolytic method has been fully consolidated using spark plasma sintering (SPS) generating microstructures comparable to those observed in Ti–6Al–4V PM product. This is the first time powder from an alternative titanium extraction method has been processed via SPS and it is benchmarked with commercial alloys (CP–Ti, Ti–6Al–4V, and Ti–5Al–5V–5Mo–3Cr). The effect of powder feedstock size, morphology, and alloy chemistry on the consoli...

  4. Low temperature spark plasma sintering of YIG powders

    International Nuclear Information System (INIS)

    Fernandez-Garcia, L.; Suarez, M.; Menendez, J.L.

    2010-01-01

    A transition from a low to a high spin state in the magnetization saturation between 1000 and 1100 o C calcination temperature is observed in YIG powders prepared by oxides mixture. Spark plasma sintering of these powders between 900 and 950 o C leads to dense samples with minimal formation of YFeO 3 , opening the way to co-sintering of YIG with metals or metallic alloys. The optical properties depend on the sintering stage: low (high) density samples show poor (bulk) optical absorption.

  5. Analysis of solids by spark-source mass spectrometry

    International Nuclear Information System (INIS)

    Stefani, R.; Desjardins, M.; Brun, J.C.; Cornu, A.; Bourguillot, R.

    1965-01-01

    Spark source mass spectrometer MS7 has been designed to determine traces of impurities in solids without standards. An atlas of 12 000 lines, assembled in the Grenoble laboratory, allows a quick investigation of mass spectra, notwithstanding their complexity due to multiply charged and polyatomic darkening. Photometric measurements increase accuracy calibration curve is known for each photo-plate. Further, reproducibility is better, if random fluctuations of matrix line darkening are corrected. So far, in a concentration range of 0,01 to 1 000 ppm (atomic), reproducibility is approximately 20 per cent, but absolute value of results depends on 'sensitivity coefficients'. (authors) [fr

  6. Manufacturing of metal supported BSCF membranes by spark plasma sintering

    OpenAIRE

    Laptev, Alexander; Bram, Martin; Zivcec, Maria; Baumann, Stefan; Jarligo, Maria Ophelia; Sebold, Doris; Pfaff, Ewald; Broeckmann, Christoph

    2013-01-01

    Spark plasma sintering (SPS), also known as field assisted sintering technique (FAST), is a relatively new method for rapid consolidation of metallic or ceramic powders. In the present work, its suitability for the manufacturing of metal supported Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) based membrane by co-sintering of functional ceramic BSCF layer and porous metallic support has been investigated. The BSCF based membranes are highly attractive for oxygen separation from air due to mixed ionic and e...

  7. Compaction of lithium-silicate ceramics using spark plasma sintering

    Czech Academy of Sciences Publication Activity Database

    Kubatík, Tomáš František; Lukáč, František; Mušálek, Radek; Brožek, Vlastimil; Stehlíková, K.; Chráska, Tomáš

    2017-01-01

    Roč. 61, č. 1 (2017), s. 40-44 ISSN 0862-5468 R&D Projects: GA ČR GB14-36566G Institutional support: RVO:61389021 Keywords : Li2Si2O5 * Li2SiO3 * Spark plasma sintering (SPS) * Quantitative Rietveld refinement * X-ray diffraction (XRD) Subject RIV: JG - Metallurgy OBOR OECD: Materials engineering Impact factor: 0.439, year: 2016 http://www.ceramics-silikaty.cz/index.php?page=cs_detail_doi&id=789

  8. Low temperature spark plasma sintering of YIG powders

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Garcia, L. [Department of Nanostructured Materials, Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN). Principado de Asturias - Consejo superior de Investigaciones Cientificas (CSIC) - Universidad de Oviedo - UO, Parque Tecnologico de Asturias, 33428 Llanera, Asturias (Spain); Suarez, M., E-mail: m.suarez@cinn.e [Department of Nanostructured Materials, Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN). Principado de Asturias - Consejo superior de Investigaciones Cientificas (CSIC) - Universidad de Oviedo - UO, Parque Tecnologico de Asturias, 33428 Llanera, Asturias (Spain); Fundacion ITMA, Parque Tecnologico de Asturias, 33428, Llanera (Spain); Menendez, J.L. [Department of Nanostructured Materials, Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN). Principado de Asturias - Consejo superior de Investigaciones Cientificas (CSIC) - Universidad de Oviedo - UO, Parque Tecnologico de Asturias, 33428 Llanera, Asturias (Spain)

    2010-07-16

    A transition from a low to a high spin state in the magnetization saturation between 1000 and 1100 {sup o}C calcination temperature is observed in YIG powders prepared by oxides mixture. Spark plasma sintering of these powders between 900 and 950 {sup o}C leads to dense samples with minimal formation of YFeO{sub 3}, opening the way to co-sintering of YIG with metals or metallic alloys. The optical properties depend on the sintering stage: low (high) density samples show poor (bulk) optical absorption.

  9. MODELING AND SIMULATION OF COMBUSTION AND DETONATION BY SUBCRITICAL STREAMER DISCHARGE

    Directory of Open Access Journals (Sweden)

    Pavel V. Bulat

    2017-07-01

    Full Text Available We consider the possibilities of combustion and detonation initiation for propane mixtured with air by microwave discharges created by a quasi-optical electromagnetic beam. Comparison of initiation is performed by different types of discharge: spark, streamer, and attached one. The formation theory of streamer discharges is given, the velocity of their propagation and the volume of energy supplies are analyzed. Experiments have been carried out together with calculation of the propane-air mixture ignition by various types of discharges. It is shown that when burning is initiated by a streamer discharge, a multiple increase in the propagation velocity of the flame front and the completeness of the fuel combustion is obtained as compared to a spark discharge with an equal energy contribution. In the prechamber initiation of combustion by igniting a streamer discharge on the inner walls of the quartz tube, a significant acceleration of combustion was obtained up to the rates characteristic for the transition of deflagration to detonation. The results can be applied in the development of multivolumetric volumetric ignition systems in internal combustion engines, gas turbine engines, low-emission combustion chambers, for combustion in supersonic flow, and in combustion chambers for detonation engines.

  10. Characterization and modeling of 2D-glass micro-machining by spark-assisted chemical engraving (SACE) with constant velocity

    International Nuclear Information System (INIS)

    Didar, Tohid Fatanat; Dolatabadi, Ali; Wüthrich, Rolf

    2008-01-01

    Spark-assisted chemical engraving (SACE) is an unconventional micro-machining technology based on electrochemical discharge used for micro-machining nonconductive materials. SACE 2D micro-machining with constant speed was used to machine micro-channels in glass. Parameters affecting the quality and geometry of the micro-channels machined by SACE technology with constant velocity were presented and the effect of each of the parameters was assessed. The effect of chemical etching on the geometry of micro-channels under different machining conditions has been studied, and a model is proposed for characterization of the micro-channels as a function of machining voltage and applied speed

  11. X-ray spectra of He-like ions of Ga and Ge, excited in the low-inductance spark plasma

    International Nuclear Information System (INIS)

    Aglitsky, E.V.; Antsiferov, P.S.; Panin, A.M.

    1984-01-01

    The spectra of Ga XXX and Ge XXXI ions in the interval 1.2-1.4 A excited in the low-inductance vacuum spark plasma have been obtained for the first time. The resonance line 1s 2 -1s2p of Ga XXX and Ge XXXI and a group of satellites, corresponding to transitions in Ga XXIX and Ge XXX can be seen distinctly in the spectra. The spectra were obtained by an electronic-optical image-intensifier tube for one discharge. (orig.)

  12. Breakover mechanism of GaAs photoconductive switch triggering spark gap for high power applications

    Science.gov (United States)

    Tian, Liqiang; Shi, Wei; Feng, Qingqing

    2011-11-01

    A spark gap (SG) triggered by a semi-insulating GaAs photoconductive semiconductor switch (PCSS) is presented. Currents as high as 5.6 kA have been generated using the combined switch, which is excited by a laser pulse with energy of 1.8 mJ and under a bias of 4 kV. Based on the transferred-electron effect and gas streamer theory, the breakover characteristics of the combined switch are analyzed. The photoexcited carrier density in the PCSS is calculated. The calculation and analysis indicate that the PCSS breakover is caused by nucleation of the photoactivated avalanching charge domain. It is shown that the high output current is generated by the discharge of a high-energy gas streamer induced by the strong local electric field distortion or by overvoltage of the SG resulting from quenching of the avalanching domain, and periodic oscillation of the current is caused by interaction between the gas streamer and the charge domain. The cycle of the current oscillation is determined by the rise time of the triggering electric pulse generated by the PCSS, the pulse transmission time between the PCSS and the SG, and the streamer transit time in the SG.

  13. Experimental study on surface properties of the PMMA used in high power spark gaps

    Science.gov (United States)

    Han, Ruoyu; Wu, Jiawei; Ding, Weidong; Liu, Yunfei; Gou, Yang

    2017-10-01

    This paper studies the surface properties of the Polymethylmethacrylate (PMMA) insulator samples used in high power spark gaps. Experiments on surface morphology, surface profile, surface chemical composition and surface leakage current were performed. Metal particles ejected in tangent direction of discharge spots were researched on the sample surface. Three kinds of distinct bands were found on the surface after 1500 shots: colorless and transparent sinking band, black band, and grey powdered coating band. The thickness of the coating band was tens of microns and the maximum radial erosion rate was about 10 μm/C. Surface content analysis indicated that the powdered coating was a mixture of decomposed insulator material and electrode material oxides. In addition, leakage current significantly depended on water content in the chamber and presented an U-shape curve distribution along the insulator surface, in keeping with the amount of powdered coating due to shock waves. Possible reasons of the surface property changes were discussed. Electroconductive oxides of low valence states of Cu and W produced by the reactions between electrode materials and arc plasmas were considered to be the cause of dielectric performance degradation.

  14. Excellent electrochemical performance of graphene-silver nanoparticle hybrids prepared using a microwave spark assistance process

    International Nuclear Information System (INIS)

    Shanmugharaj, A.M.; Ryu, Sung Hun

    2012-01-01

    Highlights: ► A simple synthesis route is explored in preparing graphene-metal nanoparticle hybrids using cost effective microwave radiation process. ► Electrochemical performance of the synthesized graphene-silver nanoparticle hybrids have been compared with graphite and silver nanoparticle based anode materials. ► Graphene-silver nanoparticle hybrid exhibits stable charge/discharge characteristics of 714 mAh g −1 and it is significantly higher compared to natural graphite and silver based electrodes. - Abstract: A simple method is described for the synthesis of graphene-silver nanoparticle hybrids from graphite and silver precursors using microwave spark ignition process. Adding ecofriendly free radical initiators, in the presence of hydrogen peroxide solution leads to the expansion of graphite to graphene nanosheets. Simultaneously, silver ions intercalated between the graphene layers are reduced to silver nanocrystals leading to the development of graphene-silver nanoparticle hybrids. Transmission electron microscopic (TEM) studies reveal the successful formation of graphene-silver nanoparticle hybrids. X-ray diffraction (XRD) shows that the silver nanoparticles formed on the graphene surfaces are face centered cubic crystals. The surface composition and functional groups present on the graphene-silver nanoparticle hybrids are corroborated using X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FT-IR). The lithium storage capacity of the synthesized material, when used as an anode material for rechargeable lithium secondary batteries is investigated. Its first specific discharge capacity is observed to be 580 mAh g −1 and this has been increased to 827 mAh g −1 , by incorporating the silver nanoparticles between the graphene platelets. The reversible capacity of the graphene-silver nanoparticle hybrids is observed to be 714 mAh g −1 , which is significantly higher compared to that of graphene (420 mAh g −1

  15. A new and efficient mechanism for spark ignition engines

    International Nuclear Information System (INIS)

    Shadloo, M.S.; Poultangari, R.; Abdollahzadeh Jamalabadi, M.Y.; Rashidi, M.M.

    2015-01-01

    Highlights: • A new slider–crank mechanism, with superior performance is presented. • Thermodynamic processes as well as vibration and internal forces have been modeled. • Comparison with the conventional four-stroke spark ignition engines is made. • Advantages and disadvantages of the proposed mechanism are discussed. - Abstract: In this paper a new symmetrical crank and slider mechanism is proposed and a zero dimensional model is utilized to study its combustion performance enhancement in a four-stroke spark ignition (SI) engine. The main features of this new mechanism are superior thermodynamic efficiency, lower internal frictions, and lower pollutants. Comparison is made between its performance and that of the conventional four-stroke SI engines. Presented mechanism is designed to provide better fuel consumption of internal combustion engines. These advantages over standard engine are achieved through synthesis of new mechanism. Numerical calculation have been performed for several cases of different mechanism parameters, compression ratio and engine speed. A comprehensive comparison between their thermodynamic processes as well as vibration and internal forces has been done. Calculated efficiency and power diagrams are plotted and compared with performance of a conventional SI engine. Advantages and disadvantages of the proposed mechanism are discussed in details

  16. Spark and HPC for High Energy Physics Data Analyses

    Energy Technology Data Exchange (ETDEWEB)

    Sehrish, Saba; Kowalkowski, Jim; Paterno, Marc

    2017-05-01

    A full High Energy Physics (HEP) data analysis is divided into multiple data reduction phases. Processing within these phases is extremely time consuming, therefore intermediate results are stored in files held in mass storage systems and referenced as part of large datasets. This processing model limits what can be done with interactive data analytics. Growth in size and complexity of experimental datasets, along with emerging big data tools are beginning to cause changes to the traditional ways of doing data analyses. Use of big data tools for HEP analysis looks promising, mainly because extremely large HEP datasets can be represented and held in memory across a system, and accessed interactively by encoding an analysis using highlevel programming abstractions. The mainstream tools, however, are not designed for scientific computing or for exploiting the available HPC platform features. We use an example from the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) in Geneva, Switzerland. The LHC is the highest energy particle collider in the world. Our use case focuses on searching for new types of elementary particles explaining Dark Matter in the universe. We use HDF5 as our input data format, and Spark to implement the use case. We show the benefits and limitations of using Spark with HDF5 on Edison at NERSC.

  17. Turbulent spark-jet ignition in SI gas fuelled engine

    Directory of Open Access Journals (Sweden)

    Pielecha Ireneusz

    2017-01-01

    Full Text Available The article contains a thermodynamic analysis of a new combustion system that allows the combustion of stratified gas mixtures with mean air excess coefficient in the range 1.4-1.8. Spark ignition was used in the pre-chamber that has been mounted in the engine cylinder head and contained a rich mixture out of which a turbulent flow of ignited mixture is ejected. It allows spark-jet ignition and the turbulent combustion of the lean mixture in the main combustion chamber. This resulted in a two-stage combustion system for lean mixtures. The experimental study has been conducted using a single-cylinder test engine with a geometric compression ratio ε = 15.5 adapted for natural gas supply. The tests were performed at engine speed n = 2000 rpm under stationary engine load when the engine operating parameters and toxic compounds emissions have been recorded. Analysis of the results allowed to conclude that the evaluated combustion system offers large flexibility in the initiation of charge ignition through an appropriate control of the fuel quantities supplied into the pre-chamber and into the main combustion chamber. The research concluded with determining the charge ignition criterion for a suitably divided total fuel dose fed to the cylinder.

  18. Advances in the electro-spark deposition coating process

    International Nuclear Information System (INIS)

    Johnson, R.N.; Sheldon, G.L.

    1986-04-01

    Electro-spark deposition (ESD) is a pulsed-arc micro-welding process using short-duration, high-current electrical pulses to deposit an electrode material on a metallic substrate. It is one of the few methods available by which a fused, metallurgically bonded coating can be applied with such a low total heat input that the bulk substrate material remains at or near ambient temperatures. The short duration of the electrical pulse allows an extremely rapid solidification of the deposited material and results in an exceptionally fine-grained, homogenous coating that approaches (and with some materials, actually is) an amorphous structure. This structure is believed to contribute to the good tribological and corrosion performance observed for hardsurfacing materials used in the demanding environments of high temperatures, liquid metals, and neutron irradiation. A brief historical review of the process is provided, followed by descriptions of the present state-of-the-art and of the performance and applications of electro-spark deposition coatings in liquid-metal-cooled nuclear reactors

  19. VariantSpark: population scale clustering of genotype information.

    Science.gov (United States)

    O'Brien, Aidan R; Saunders, Neil F W; Guo, Yi; Buske, Fabian A; Scott, Rodney J; Bauer, Denis C

    2015-12-10

    Genomic information is increasingly used in medical practice giving rise to the need for efficient analysis methodology able to cope with thousands of individuals and millions of variants. The widely used Hadoop MapReduce architecture and associated machine learning library, Mahout, provide the means for tackling computationally challenging tasks. However, many genomic analyses do not fit the Map-Reduce paradigm. We therefore utilise the recently developed SPARK engine, along with its associated machine learning library, MLlib, which offers more flexibility in the parallelisation of population-scale bioinformatics tasks. The resulting tool, VARIANTSPARK provides an interface from MLlib to the standard variant format (VCF), offers seamless genome-wide sampling of variants and provides a pipeline for visualising results. To demonstrate the capabilities of VARIANTSPARK, we clustered more than 3,000 individuals with 80 Million variants each to determine the population structure in the dataset. VARIANTSPARK is 80 % faster than the SPARK-based genome clustering approach, ADAM, the comparable implementation using Hadoop/Mahout, as well as ADMIXTURE, a commonly used tool for determining individual ancestries. It is over 90 % faster than traditional implementations using R and Python. The benefits of speed, resource consumption and scalability enables VARIANTSPARK to open up the usage of advanced, efficient machine learning algorithms to genomic data.

  20. A Simulation of Pre-Arcing Plasma Discharge Processes in Water Purification

    International Nuclear Information System (INIS)

    Rodriguez-Mendez, B. G.; Piedad-Beneitez, A. de la; Lopez-Callejas, R.; Godoy-Cabrera, O. G.; Benitez-Read, J. S.; Pacheco-Sotelo, J. O.; Pena-Eguiluz, R.; Mercado-Cabrera, A.; Valencia-A, R.; Barocio, S. R.

    2006-01-01

    The simulation of a water purification system within a coaxial cylinder reactor operated by 1 kHz frequency plasma discharges in pre-arcing regimes is presented. In contrast with precedent works, this computational model considers three mechanisms of the system operation: (a) the relevant physical characteristics of water (b) the ionisation and expansion processes in the spark channel including the near-breakdown electric current generated by the rate of change of the effective capacitance and resistance in the discharge, and (c) the energy associated with this initial spark in the water. The outcome of the model seems to meet all main requirements to allow the design and construction of specific water purification technology devices

  1. Vessel Sewage Discharges

    Science.gov (United States)

    Vessel sewage discharges are regulated under Section 312 of the Clean Water Act, which is jointly implemented by the EPA and Coast Guard. This homepage links to information on marine sanitation devices and no discharge zones.

  2. Foot amputation - discharge

    Science.gov (United States)

    Amputation - foot - discharge; Trans-metatarsal amputation - discharge ... You have had a foot amputation. You may have had an accident, or your foot may have had an infection or disease and doctors could ...

  3. Elbow replacement - discharge

    Science.gov (United States)

    Total elbow arthroplasty - discharge; Endoprosthetic elbow replacement - discharge ... Pain is normal after elbow replacement surgery. It should get better over time. Your doctor will give you a prescription for pain medicine. Get it filled when ...

  4. Vaginal delivery - discharge

    Science.gov (United States)

    Pregnancy - discharge after vaginal delivery ... return in: 4 to 9 weeks after your delivery if you're not breastfeeding 3 to 12 ... can start sexual activity around 6 weeks after delivery, if the discharge or lochia has stopped. Women ...

  5. Benefits and applications of laser-induced sparks in real scale model measurements

    DEFF Research Database (Denmark)

    Gómez-Bolaños, Javier; Delikaris-Manias, Symeon; Pulkki, Ville Topias

    2015-01-01

    The characteristics of using a laser-induced spark as a monopole source in scale model measurements were assessed by comparison with an electric spark and a miniature spherical loudspeaker. Room impulse responses of first order directivity sources were synthesized off-line using six spatially dis...

  6. 77 FR 20388 - California State Nonroad Engine Pollution Control Standards; Large Spark-Ignition (LSI) Engines...

    Science.gov (United States)

    2012-04-04

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9655-9] California State Nonroad Engine Pollution Control Standards; Large Spark-Ignition (LSI) Engines; New Emission Standards and In-Use Fleet Requirements; Notice... emission standards and certification and test procedures for large spark-ignition nonroad engines and in...

  7. 76 FR 67184 - California State Nonroad Engine Pollution Control Standards; Large Spark-Ignition (LSI) Engines...

    Science.gov (United States)

    2011-10-31

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9484-9] California State Nonroad Engine Pollution Control Standards; Large Spark-Ignition (LSI) Engines; Fleet Requirements for In-Use LSI Forklifts and Other... its emission standards and certification and test procedures for large spark-ignition nonroad engines...

  8. Heart attack - discharge

    Science.gov (United States)

    ... and lifestyle Cholesterol - drug treatment Controlling your high blood pressure Deep vein thrombosis - discharge Dietary fats explained Fast food tips Heart attack - discharge Heart attack - what to ask your doctor Heart bypass ... pacemaker - discharge High blood pressure - what to ask your doctor How to read ...

  9. Preliminary Development of Spectrochemical Analysis of Superalloys with the Liquid-Layer Solid-Sample Spark Technique

    National Research Council Canada - National Science Library

    Barnes, Ramon

    1969-01-01

    A comparison study is made, for the spectrochemical analysis of cobalt-base superalloys, between the liquid-layer solid-sample spark technique and the conventional point-to-plane spark analysis in air...

  10. SciSpark: Highly Interactive and Scalable Model Evaluation and Climate Metrics for Scientific Data and Analysis

    Data.gov (United States)

    National Aeronautics and Space Administration — We will construct SciSpark, a scalable system for interactive model evaluation and for the rapid development of climate metrics and analyses. SciSpark directly...

  11. Spark protection layers for CMOS pixel anode chips in MPGDs

    NARCIS (Netherlands)

    Bilevych, Y.; Bilevych, Y.; Blanco Carballo, V.M.; Chefdeville, M.A.; Colas, P.; Delagnes, E.; Fransen, M.; van der Graaff, H.; Koppert, W.J.C.; Melai, J.; Salm, Cora; Schmitz, Jurriaan; Timmermans, J.; Timmermans, J.; Wyrsch, N.

    2011-01-01

    In this work we have investigated the functioning of high resistivity amorphous silicon and silicon-rich nitride layers as a protection against discharges in Micro-Patterned Gaseous Detectors (MPGDs).When the anode is protected by a high resistivity layer, discharge signals are limited in charge. A

  12. Number density measurements on analytical discharge systems: application of ''hook'' spectroscopy

    International Nuclear Information System (INIS)

    Majidi, V.; Hsu, W.; Coleman, D.M.

    1988-01-01

    Various methods for determining atomic, ionic and electron number densities are reviewed. Time- and spatially-resolved number densities of sodium atoms in the post discharge environment of a high voltage spark are then quantitatively determined using the anomalous dispersion hook method. Number densities are calculated from hook separation near the Na D-lines. Lateral profiles are subsequently transformed to the radial domain using a derivative free Abel inversion process. Advantages, limitations, and practical ramification of the hook method are discussed. (author)

  13. A new spark detection system for the electrostatic septa of the SPS North (experimental) Area

    CERN Multimedia

    Barlow, R A; Borburgh, J; Carlier, E; Chanavat, C; Pinget, B

    2013-01-01

    Electrostatic septa (ZS) are used in the extraction of the particle beams from the CERN SPS to the North Area experimental zone. These septa employ high electric fields, generated from a 300 kV power supply, and are particularly prone to internal sparking around the cathode structure. This sparking degrades the electric field quality, consequently affecting the extracted beam, vacuum and equipment performance. To mitigate these effects, a Spark Detection System (SDS) has been realised, which is based on an industrial SIEMENS S7-400 programmable logic controller and deported Boolean processors modules interfaced through a PROFINET fieldbus. The SDS interlock logic uses a moving average spark rate count to determine if the ZS performance is acceptable. Below a certain spark rate it is probable that the ZS septa tank vacuum can recover, thus avoiding transition into a\

  14. SparkBLAST: scalable BLAST processing using in-memory operations.

    Science.gov (United States)

    de Castro, Marcelo Rodrigo; Tostes, Catherine Dos Santos; Dávila, Alberto M R; Senger, Hermes; da Silva, Fabricio A B

    2017-06-27

    The demand for processing ever increasing amounts of genomic data has raised new challenges for the implementation of highly scalable and efficient computational systems. In this paper we propose SparkBLAST, a parallelization of a sequence alignment application (BLAST) that employs cloud computing for the provisioning of computational resources and Apache Spark as the coordination framework. As a proof of concept, some radionuclide-resistant bacterial genomes were selected for similarity analysis. Experiments in Google and Microsoft Azure clouds demonstrated that SparkBLAST outperforms an equivalent system implemented on Hadoop in terms of speedup and execution times. The superior performance of SparkBLAST is mainly due to the in-memory operations available through the Spark framework, consequently reducing the number of local I/O operations required for distributed BLAST processing.

  15. Controlling spark timing for consecutive cycles to reduce the cyclic variations of SI engines

    International Nuclear Information System (INIS)

    Kaleli, Alirıza; Ceviz, Mehmet Akif; Erenturk, Köksal

    2015-01-01

    Minimization of the cyclic variations is one of the most important design goal for spark-ignited engines. Primary motivation of this study is to reduce the cyclic variations in spark ignition engines by controlling the spark timing for consecutive cycles. A stochastic model was performed between spark timing and in–cylinder maximum pressure by using the system identification techniques. The incylinder maximum pressure of the next cycle was predicted with this model. Minimum variance and generalized minimum variance controllers were designed to regulate the in–cylinder maximum pressure by changing the spark timing for consecutive cycles of the test engine. The produced control algorithms were built in LabView environment and installed to the Field Programmable Gate Arrays (FPGA) chassis. According to the test results, the in–cylinder maximum pressure of the next pressure cycle can be predicted fairly well, and the spark timing can be regulated to keep the in–cylinder maximum pressure in a desired band to reduce the cyclic variations. At fixed spark timing experiments, the COV Pmax and COV imep were 3.764 and 0.677%, whereas they decreased to 3.208 and 0.533% when GMV controller was applied, respectively. - Highlights: • Cycle per cycle spark timing control was carried out. • A stochastic process model was described between P max and the spark timing. • The cyclic variations in P max was decreased by keeping it in a desired band. • Different controllers were used to adjust spark timing signal of the next cycle. • COV Pmax was decreased by about 15% by using GMV controller

  16. Neutron irradiation effects on spark plasma sintered boron carbide

    International Nuclear Information System (INIS)

    Buyuk, B.; Cengiz, M.; Tugrul, A.; Ozer, S.; Yucel, O.; Goller, G.; Sahin, F.C.; Lastovski, S.B.

    2015-01-01

    In this study, spark plasma sintered boron carbide (B 4 C) was examined against neutrons. The specimens were ir-radiated by reactor neutrons (include both thermal and fast neutrons) up to fluence of 1.37x10 21 n*m -2 . Thermal and fast neutrons cause swelling by different interactions with boron ( 10 B) atoms in the related materials. X-Ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images were investigated for initial and irradiated samples. In addition, lattice parameters and unit cell volumes were calculated for the samples. The swelling percentages were calculated to be within a range of 0.49-3.80 % (average 1.70 %) for the outer surface of the materials for applied neutron irradiation doses. (authors)

  17. Quartz crystal reinforced quartz glass by spark plasma sintering

    International Nuclear Information System (INIS)

    Torikai, D.; Barazani, B.; Ono, E.; Santos, M.F.M.; Suzuki, C.K.

    2011-01-01

    The Spark Plasma Sintering presents fast processing time when compared to conventional sintering techniques. This allows to control the grain growth during sintering as well as the diffusion rate of a multi-material compounds, and make possible obtainment of functionally graded materials and nanostructured compounds. Powders of high purity silica glass and crystalline silica were sintered in a SPS equipment at temperatures around 1350° C, i.e., above the softening temperature of silica glass and below the melting temperature of quartz crystal. As a result, glass ceramics with pure silica glass matrix reinforced with crystalline alpha-quartz grains were fabricated at almost any desired range of composition, as well as controlled size of the crystalline reinforcement. X-ray diffraction and density measurements showed the possibility to manufacture a well controlled density and crystallinity glass-ceramic materials. (author)

  18. Development of microwave-enhanced spark-induced breakdown spectroscopy

    International Nuclear Information System (INIS)

    Ikeda, Yuji; Moon, Ahsa; Kaneko, Masashi

    2010-01-01

    We propose microwave-enhanced spark-induced breakdown spectroscopy with the same measurement and analysis processes as in laser-induced breakdown spectroscopy, but with a different plasma generation mechanism. The size and lifetime of the plasma generated can contribute to increased measurement accuracy and expand its applicability to industrial measurement, such as an exhaust gas analyzer for automobile engine development and its regulation, which has been hard to operate by laser at an engineering evaluation site. The use of microwaves in this application helps lower the cost, reduce the system size, and increase the ease of operation to make it commercially viable. A microwave frequency of 2.45 GHz was used to enhance the volume and lifetime of the plasma at atmospheric condition even at elevated pressure.

  19. Distributed Parallel Endmember Extraction of Hyperspectral Data Based on Spark

    Directory of Open Access Journals (Sweden)

    Zebin Wu

    2016-01-01

    Full Text Available Due to the increasing dimensionality and volume of remotely sensed hyperspectral data, the development of acceleration techniques for massive hyperspectral image analysis approaches is a very important challenge. Cloud computing offers many possibilities of distributed processing of hyperspectral datasets. This paper proposes a novel distributed parallel endmember extraction method based on iterative error analysis that utilizes cloud computing principles to efficiently process massive hyperspectral data. The proposed method takes advantage of technologies including MapReduce programming model, Hadoop Distributed File System (HDFS, and Apache Spark to realize distributed parallel implementation for hyperspectral endmember extraction, which significantly accelerates the computation of hyperspectral processing and provides high throughput access to large hyperspectral data. The experimental results, which are obtained by extracting endmembers of hyperspectral datasets on a cloud computing platform built on a cluster, demonstrate the effectiveness and computational efficiency of the proposed method.

  20. A prediction study of a spark ignition supercharged hydrogen engine

    International Nuclear Information System (INIS)

    Al-Baghdadi, Maher A.R. Sadiq.; Al-Janabi, Haroun A.K. Shahad

    2003-01-01

    Hydrogen is found to be a suitable alternative fuel for spark ignition engines with certain drawbacks, such as high NO x emission and small power output. However, supercharging may solve such problems. In this study, the effects of equivalence ratio, compression ratio and inlet pressure on the performance and NO x emission of a four stroke supercharged hydrogen engine have been analyzed using a specially developed computer program. The results are verified and compared with experimental data obtained from tests on a Ricardo E6/US engine. A chart specifying the safe operation zone of the hydrogen engine has been produced. The safe operation zone means no pre-ignition, acceptable NO x emission, high engine efficiency and lower specific fuel consumption in comparison with the gasoline engine. The study also shows that supercharging is a more effective method to increase the output of a hydrogen engine rather than increasing the compression ratio of the engine at the knock limited equivalence ratio

  1. Temperature-dependent thermal properties of spark plasma sintered alumina

    Directory of Open Access Journals (Sweden)

    Saheb Nouari

    2017-01-01

    Full Text Available In this work, we report temperature-dependent thermal properties of alumina powder and bulk alumina consolidated by spark plasma sintering method. The properties were measured between room temperature and 250ºC using a thermal constants analyzer. Alumina powder had very low thermal properties due to the presence of large pores and absence of bonding between its particles. Fully dense alumina with a relative density of 99.6 % was obtained at a sintering temperature of 1400°C and a holding time of 10 min. Thermal properties were found to mainly dependent on density. Thermal conductivity, thermal diffusivity, and specific heat of the fully dense alumina were 34.44 W/mK, 7.62 mm2s-1, and 1.22 J/gK, respectively, at room temperature. Thermal conductivity and thermal diffusivity decreased while specific heat increased with the increase in temperature from room temperature to 250ºC.

  2. Human resource recommendation algorithm based on ensemble learning and Spark

    Science.gov (United States)

    Cong, Zihan; Zhang, Xingming; Wang, Haoxiang; Xu, Hongjie

    2017-08-01

    Aiming at the problem of “information overload” in the human resources industry, this paper proposes a human resource recommendation algorithm based on Ensemble Learning. The algorithm considers the characteristics and behaviours of both job seeker and job features in the real business circumstance. Firstly, the algorithm uses two ensemble learning methods-Bagging and Boosting. The outputs from both learning methods are then merged to form user interest model. Based on user interest model, job recommendation can be extracted for users. The algorithm is implemented as a parallelized recommendation system on Spark. A set of experiments have been done and analysed. The proposed algorithm achieves significant improvement in accuracy, recall rate and coverage, compared with recommendation algorithms such as UserCF and ItemCF.

  3. What sparks interest in science? A naturalistic inquiry

    Science.gov (United States)

    Jackson, Julie Kay Cropper

    This study examined how career scientists became interested in science. Eight practicing scientists were asked a focus question, "What sparked your interest in science?" Their responses recorded during personal interviews and reported in correspondence frame this qualitative study. Analysis of the data revealed a variety of influences. The influences were coded, arranged into lists, and grouped by theme. A total of 18 themes emerged from the data. Five of the emerging themes were common across all of the participants. They were the influence of a family member, the influence of a teacher, being naturally curious, being interested in science, and reading books, magazines, and/or encyclopedias. Five themes were common among 5 to 7 participants. These themes included visiting museums, having broad exposure, enjoyment of mathematics, enjoying being outside, and freedom to play and explore. Eight themes were common among 2 to 4 of the participants. They were financial incentive, influence of religion, participation in science fairs, influence of the manned space program, having a scientist in the family, having the opportunity to teach others, not seeing self as a scientist, and first generation college graduate. The emerging themes were compared and contrasted with historical and contemporary literature. Vocational psychology's leading career choice and development literature was also aligned with the emerging themes. Data from this study supports tenets of Trait and Factor Theory, Developmental Theory, and Social Learning Theory. Reported data also supports the proposed movement toward a unified theory of career choice and development. A combination of personality traits, developmental stages, self-efficacy, and learning experiences influenced the vocational decisions of the scientists who participated in this study. The study concludes with suggestions for sparking and sustaining interest in science that people responsible for preparing future scientists may find

  4. SciSpark: In-Memory Map-Reduce for Earth Science Algorithms

    Science.gov (United States)

    Ramirez, P.; Wilson, B. D.; Whitehall, K. D.; Palamuttam, R. S.; Mattmann, C. A.; Shah, S.; Goodman, A.; Burke, W.

    2016-12-01

    We are developing a lightning fast Big Data technology called SciSpark based on ApacheTM Spark under a NASA AIST grant (PI Mattmann). Spark implements the map-reduce paradigm for parallel computing on a cluster, but emphasizes in-memory computation, "spilling" to disk only as needed, and so outperforms the disk-based Apache Hadoop by 100x in memory and by 10x on disk. SciSpark extends Spark to support Earth Science use in three ways: Efficient ingest of N-dimensional geo-located arrays (physical variables) from netCDF3/4, HDF4/5, and/or OPeNDAP URLS; Array operations for dense arrays in scala and Java using the ND4S/ND4J or Breeze libraries; Operations to "split" datasets across a Spark cluster by time or space or both. For example, a decade-long time-series of geo-variables can be split across time to enable parallel "speedups" of analysis by day, month, or season. Similarly, very high-resolution climate grids can be partitioned into spatial tiles for parallel operations across rows, columns, or blocks. In addition, using Spark's gateway into python, PySpark, one can utilize the entire ecosystem of numpy, scipy, etc. Finally, SciSpark Notebooks provide a modern eNotebook technology in which scala, python, or spark-sql codes are entered into cells in the Notebook and executed on the cluster, with results, plots, or graph visualizations displayed in "live widgets". We have exercised SciSpark by implementing three complex Use Cases: discovery and evolution of Mesoscale Convective Complexes (MCCs) in storms, yielding a graph of connected components; PDF Clustering of atmospheric state using parallel K-Means; and statistical "rollups" of geo-variables or model-to-obs. differences (i.e. mean, stddev, skewness, & kurtosis) by day, month, season, year, and multi-year. Geo-variables are ingested and split across the cluster using methods on the sciSparkContext object including netCDFVariables() for spatial decomposition and wholeNetCDFVariables() for time-series. The

  5. Calcium Hex aluminate reaction sintering by Spark Plasma Sintering; Sinterizacion reactiva de Hexaluminato de Calcio mediante Spark Plasma Sintering

    Energy Technology Data Exchange (ETDEWEB)

    Iglesia, P. G. de la; Garcia-Moreno, O.; Torrecillas, R.; Menendez, J. L.

    2012-11-01

    Calcium hex aluminate (CaAl{sub 1}2O{sub 1}9) is the most alumina-rich intermediate compound of the CaO-Al{sub 2}O{sub 3} system. The formation of this aluminate is produced by the reaction between calcium oxide and alumina with the consequent formation of intermediates compounds with lower alumina content with increasing temperature (CaAl{sub 2}O{sub 4}, CaAl4O{sub 7}). In this study we studied the variation of sintering parameters for obtaining dense and pure calcium hex aluminate by reaction sintering by Spark Plasma Sintering (SPS). A mixing of Al{sub 2}O{sub 3} and CaCO{sub 3} were used as reactive. Final densities close to the theoretical and phase transformation over 93% were achieved by this method. (Author) 22 refs.

  6. Interface behavior of tungsten coating on stainless steel by electro spark deposition

    Directory of Open Access Journals (Sweden)

    Wang Yuangang

    2015-01-01

    Full Text Available A new method of electro spark deposition method was put forward, which was based on the theory of electro spark deposition by changing the polarity in the liquid. Tungsten coating layers was produced on surface of Stainless Steel by electro spark deposition. The micro hardness, microstructure, chemical composition and phases of the coating layer were examined by means of hardness test, scanning electron microscopy (SEM and energy dispersive spectrometer (EDS analysis. The results showed that there was tungsten coating in the surface, which was discontinuous. Microhardness of the coating layer was about 3 times more than that of the substrate. The combination between coating layer and substrate was metallurgical bond.

  7. A time-varying copula mixture for hedging the clean spark spread with wind power futures

    DEFF Research Database (Denmark)

    Christensen, Troels Sønderby; Pircalabu, Anca; Høg, Esben

    2018-01-01

    trading in the spot clean spark spread and wind power futures. To facilitate hedging decisions, we propose a time-varying copula mixture for the joint behavior of the spot clean spark spread and the daily wind index. The model describes the data surprisingly well, both in terms of the marginals...... and the dependence structure, while being straightforward and easy to implement. Based on Monte Carlo simulations from the proposed model, the results indicate that significant benefits can be achieved by using wind power futures to hedge the spot clean spark spread. Moreover, a comparison study shows...

  8. Improving the Tribological Properties of Spark-Anodized Titanium by Magnetron Sputtered Diamond-Like Carbon

    OpenAIRE

    Zhaoxiang Chen; Xipeng Ren; Limei Ren; Tengchao Wang; Xiaowen Qi; Yulin Yang

    2018-01-01

    Spark-anodization of titanium can produce adherent and wear-resistant TiO2 film on the surface, but the spark-anodized titanium has lots of surface micro-pores, resulting in an unstable and high friction coefficient against many counterparts. In this study, the diamond-like carbon (DLC) was introduced into the micro-pores of spark-anodized titanium by the magnetron sputtering technique and a TiO2/DLC composite coating was fabricated. The microstructure and tribological properties of TiO2/DLC ...

  9. The secular and the supernatural: madness and psychiatry in the short stories of Muriel Spark.

    Science.gov (United States)

    Beveridge, A W

    2015-01-01

    Edinburgh-born Muriel Spark is one of modern Scotland's greatest writers. Examination of her work reveals that the subjects of madness and psychiatry are recurrent themes in her writing. She herself had a mental breakdown when she was a young woman and she took an interest in the world of psychiatry and psychoanalysis. In her short stories, Spark approaches the subject of madness in a variety of ways: she relates it to the supernatural; to writing fiction; and to religion. She frequently juxtaposes secular and supernatural explanations of mental disturbance. Spark adopts a sceptical and, at times, mocking view of psychiatrists and psychiatric treatment. Both psychoanalysis and pills are seen as problematic.

  10. Magnetic field-assisted electrochemical discharge machining

    International Nuclear Information System (INIS)

    Cheng, Chih-Ping; Mai, Chao-Chuang; Wu, Kun-Ling; Hsu, Yu-Shan; Yan, Biing-Hwa

    2010-01-01

    Electrochemical discharge machining (ECDM) is an effective unconventional method for micromachining in non-conducting materials, such as glass, quartz and some ceramics. However, since the spark discharge performance becomes unpredictable as the machining depth increases, it is hard to achieve precision geometry and efficient machining rate in ECDM drilling. One of the main factors for this is the lack of sufficient electrolyte flow in the narrow gap between the tool and the workpiece. In this study a magnetohydrodynamic (MHD) convection, which enhances electrolyte circulation has been applied to the ECDM process in order to upgrade the machining accuracy and efficiency. During electrolysis in the presence of a magnetic field, the Lorenz force induces the charged ions to form a MHD convection. The MHD convection then forces the electrolyte into movement, thus enhancing circulation of electrolyte. Experimental results show that the MHD convection induced by the magnetic field can effectively enhance electrolyte circulation in the micro-hole, which contributes to higher machining efficiency. Micro-holes in glass with a depth of 450 µm are drilled in less than 20 s. At the same time, better electrolyte circulation can prevent deterioration of gas film quality with increasing machining depth, while ensuring stable electrochemical discharge. The improvement in the entrance diameter thus achieved was 23.8% while that in machining time reached 57.4%. The magnetic field-assisted approach proposed in the research does not require changes in the machining setup or electrolyte but has proved to achieve significant enhancement in both accuracy and efficiency of ECDM.

  11. Early discharge following birth

    DEFF Research Database (Denmark)

    Nilsson, Ingrid M. S.; Kronborg, Hanne; Knight, Christopher H.

    2017-01-01

    of discharge after birth. Results In total 34% mothers were discharged within 12 hours (very early) and 25% between 13 and 50 hours (early), respectively. Vaginal birth and multiparity were the most influential predictors, as Caesarean section compared to vaginal birth had an OR of 0.35 (CI 0....... Smoking, favourable social support and breastfeeding knowledge were significantly associated with discharge within 12 hours. Finally time of discharge varied significantly according to region and time of day of birth. Conclusions Parity and birth related factors were the strongest predictors of early...

  12. Characteristics of cold atmospheric plasma source based on low-current pulsed discharge with coaxial electrodes

    Science.gov (United States)

    Bureyev, O. A.; Surkov, Yu S.; Spirina, A. V.

    2017-05-01

    This work investigates the characteristics of the gas discharge system used to create an atmospheric pressure plasma flow. The plasma jet design with a cylindrical graphite cathode and an anode rod located on the axis of the system allows to realize regularly reproducible spark breakdowns mode with a frequency ∼ 5 kHz and a duration ∼ 40 μs. The device generates a cold atmospheric plasma flame with 1 cm in diameter in the flow of various plasma forming gases including nitrogen and air at about 100 mA average discharge current. In the described construction the cathode spots of individual spark channels randomly move along the inner surface of the graphite electrode creating the secondary plasma stream time-average distributed throughout the whole exit aperture area after the decay of numerous filamentary discharge channels. The results of the spectral diagnostics of plasma in the discharge gap and in the stream coming out of the source are presented. Despite the low temperature of atoms and molecules in plasma stream the cathode spots operation with temperature of ∼ 4000 °C at a graphite electrode inside a discharge system enables to saturate the plasma by CN-radicals and atomic carbon in the case of using nitrogen as the working gas.

  13. Graywater Discharges from Vessels

    Science.gov (United States)

    2011-11-01

    both sewage and graywater, or sewage collected from “ honey dipper” trucks, which may contain far less graywater, depending on the source (See... crystal clean effluent discharge. As a reference, Cruiseliners equipped with Scanship AWP systems has obtained continous discharge permits in Hawaii and

  14. Paediatric vaginal discharge

    African Journals Online (AJOL)

    Vaginal discharge in the prepubertal patient is a common symptom, and can be a source of distress for the caregiver and con- cern for the healthcare worker. Several factors predispose these patients to the development of recurrent vaginal discharge. Unless noticed by the caregiver, this problem can persist for long periods ...

  15. Prostate brachytherapy - discharge

    Science.gov (United States)

    ... nausea or vomiting Any new or unusual symptoms Alternative Names Implant therapy - prostate cancer - discharge; Radioactive seed placement - discharge References D'Amico AV, Nguyen PL, Crook JM, et al. Radiation therapy for prostate cancer. In: Wein AJ, Kavoussi LR, Partin AW, Peters CA, ...

  16. High speed streak techniques for measuring the growth of spark channels

    International Nuclear Information System (INIS)

    Suleebka, P.

    1975-01-01

    The manner of expansion of an electric spark channel is of interest in the understanding of such phenomena as lightning. The development of a camera suitable for photography of this expansion is described, with some results for hydrogen. (author)

  17. An image scanner for real time analysis of spark chamber images

    International Nuclear Information System (INIS)

    Cesaroni, F.; Penso, G.; Locci, A.M.; Spano, M.A.

    1975-01-01

    The notes describes the semiautomatic scanning system at LNF for the analysis of spark chamber images. From the projection of the images on the scanner table, the trajectory in the real space is reconstructed

  18. Torch-Augmented Spark Igniter for Nanosat Launch Vehicle LOX/Propylene Rocket Engine, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The technical innovation proposed here is the introduction of torch-augmented spark ignition for high performance liquid oxygen (LOX) / propylene rocket engines now...

  19. Passenger Car Spark Ignition Data Base : Volume 3. Miscellaneous Data. Part 2.

    Science.gov (United States)

    1979-12-01

    Test data was obtained from spark ignition production and preproduction engines at the engine and vehicle level. The engines were applicable for vehicles 2000 to 3000 pounds in weight. The data obtained provided trade-offs between fuel economy, power...

  20. Passenger Car Spark Ignition Data Base : Volume 3. Miscellaneous Data. Part 1.

    Science.gov (United States)

    1979-12-01

    Test data was obtained from spark ignition production and preproduction engines at the engine and vehicle level. The engines were applicable for vehicles 2000 to 3000 pounds in weight. The data obtained provided trade-offs between fuel economy, power...

  1. Preparation of Ni-Ti shape memory alloy by spark plasma sintering method

    Czech Academy of Sciences Publication Activity Database

    Salvetr, P.; Kubatík, Tomáš František; Novák, P.

    2016-01-01

    Roč. 16, č. 4 (2016), s. 804-808 ISSN 1213-2489 Institutional support: RVO:61389021 Keywords : Ni-Ti alloy * Powder metallurgy * Reactive sintering * Spark plasma sintering Subject RIV: JK - Corrosion ; Surface Treatment of Materials

  2. Status of the Pestov spark counter development for the ALICE experiment

    International Nuclear Information System (INIS)

    Badura, E.; Dodokhov, V.; Eschke, J.; Frolov, A.R.; Gutbrod, H.H.; Grigoriev, V.; Kaplin, V.; Kopf, U.; Lobanov, V.; Neyer, C.; Pestov, Yu.N.; Schulze, R.; Steinhaeuser, P.; Stelzer, H.; Tiunov, M.A.

    1996-05-01

    The performance of a new ALICE prototype Pestov spark counter was measured both in dedicated test beam as well as in a high multiplicity heavy-ion environment. Results in terms of time resolution and background behaviour are presented. (orig.)

  3. Spark PRM: Using RRTs within PRMs to efficiently explore narrow passages

    KAUST Repository

    Shi, Kensen

    2014-05-01

    © 2014 IEEE. Probabilistic RoadMaps (PRMs) have been successful for many high-dimensional motion planning problems. However, they encounter difficulties when mapping narrow passages. While many PRM sampling methods have been proposed to increase the proportion of samples within narrow passages, such difficult planning areas still pose many challenges. We introduce a novel algorithm, Spark PRM, that sparks the growth of Rapidly-expanding Random Trees (RRTs) from narrow passage samples generated by a PRM. The RRT rapidly generates further narrow passage samples, ideally until the passage is fully mapped. After reaching a terminating condition, the tree stops growing and is added to the roadmap. Spark PRM is a general method that can be applied to all PRM variants. We study the benefits of Spark PRM with a variety of sampling strategies in a wide array of environments. We show significant speedups in computation time over RRT, Sampling-based Roadmap of Trees (SRT), and various PRM variants.

  4. CO-AXIAL DISCHARGES

    Science.gov (United States)

    Luce, J.S.; Smith, L.P.

    1960-11-22

    A method and apparatus are given for producing coaxial arc discharges in an evacuated enclosure and within a strong, confining magnetic field. The arcs are maintained at a high potential difference. Electrons will diffuse to the more positive arc from the negative arc, and positive ions will diffuse from the more positive arc to the negative arc. Coaxial arc discharges have the advantage that ions which return to strike the positive arc discharge will lose no energy since they do not strike a solid wall or electrode. Those discharges are useful in confining an ionized plasma between the discharges, and have the advantage of preventing impurities from the walls of the enclosure from entering ihe plasma area because of the arc barrier set up bv the cylindrical outer arc.

  5. Predicting tile drainage discharge

    DEFF Research Database (Denmark)

    Iversen, Bo Vangsø; Kjærgaard, Charlotte; Petersen, Rasmus Jes

    More than 50 % of Danish agricultural areas are expected to be artificial tile drained. Transport of water and nutrients through the tile drain system to the aquatic environment is expected to be significant. For different mitigation strategies such as constructed wetlands an exact knowledge...... of the water load coming from the tile drainage system is therefore essential. This work aims at predicting tile drainage discharge using dynamic as well as a statistical predictive models. A large dataset of historical tile drain discharge data, daily discharge values as well as yearly average values were...... used in the analysis. For the dynamic modelling, a simple linear reservoir model was used where different outlets in the model represented tile drain as well as groundwater discharge outputs. This modelling was based on daily measured tile drain discharge values. The statistical predictive model...

  6. Modelling electric discharge chemistry

    International Nuclear Information System (INIS)

    McFarlane, J.; Wren, J.C.

    1991-07-01

    The chemistry occurring in a electric discharge was modelled to predict how it would be influenced by discharge conditions. The discharge was characterized by a calculated Boltzmann electron-energy distribution, from which rate constants for electron-molecule processes in air were determined. These rate constants were used in a chemical kinetics calculation that also included reactions between neutral molecules, ions, free radicals and electronically excited species. The model describes how the discharge chemistry was influenced by humidity, electric field, electron number density, and concentrations of key reagents identified in the study. The use of an electric discharge to destroy airborne contaminant molecules was appraised, the targeted contaminants being CF 2 Cl 2 , HCN, and SO 2 . The modelling results indicate that an electric discharge should be able to remove HCN and CF 2 Cl 2 effectively, especially if the discharge conditions have been optimized. Effective destruction is achieved with a moderate electric field (over 1 x 10 -15 V.cm 2 ), a substantial electron number density (over 1 x 10 12 cm -3 ), and the presence of H 2 0 in the process air. The residence time in the discharge was also shown to be important in contaminant destruction. An attempt was made to explain the results of the electric discharge abatement of SO 2 , a component of a simulated flue-gas mixture. Results from the model indicate that the discharge parameters that increase the concentration of hydroxyl radical also increase the rate of decomposition of SO 2 . An objective of the study was to explain the apparent enhancement of SO 2 destruction by the presence of a small amount of NO 2 . It was thought that a likely explanation would be the stabilization of HOSO 2 , an important intermediate in the oxidation of SO 2 by NO 2 . (49 figs., 14 tabs., 75 refs.)

  7. Analyzing large data sets from XGC1 magnetic fusion simulations using apache spark

    Energy Technology Data Exchange (ETDEWEB)

    Churchill, R. Michael [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

    2016-11-21

    Apache Spark is explored as a tool for analyzing large data sets from the magnetic fusion simulation code XGCI. Implementation details of Apache Spark on the NERSC Edison supercomputer are discussed, including binary file reading, and parameter setup. Here, an unsupervised machine learning algorithm, k-means clustering, is applied to XGCI particle distribution function data, showing that highly turbulent spatial regions do not have common coherent structures, but rather broad, ring-like structures in velocity space.

  8. Utilization of waste glycerin to fuelling of spark ignition engines

    Science.gov (United States)

    Stelmasiak, Z.; Pietras, D.

    2016-09-01

    The paper discusses a possibilities of usage a simple alcohols to fuelling of spark ignition engines. Methanol and blends of methanol with glycerin, being a waste product from production of bio-components to fuels based on rapeseed oil, have been used in course of the investigations. The main objective of the research was to determine possibilities of utilization of glycerin to blending of engine fuels. The investigations have been performed using the Fiat 1100 MPI engine. Parameters obtained with the engine powered by pure methanol and by methanol- glycerin mixtures with 10÷30%vol content of glycerin were compared to parameters of the engine fuelled conventionally with the E95 gasoline. The investigations have shown increase of overall efficiency of the engine run on pure methanol with 2.5÷5.0%, and run on the mixture having 10% addition of glycerin with 2.0÷7.8%. Simultaneously, fuelling of the engine with the investigated alcohols results in reduced concentration of toxic components in exhaust gases like: CO, THC and NOx, as well as the greenhouse gas CO2.

  9. DEDICATED EXHAUST GAS RECIRCULATION IN SPARK IGNITION ENGINES

    Directory of Open Access Journals (Sweden)

    Sooraj Rehan

    2017-06-01

    Full Text Available The impact of high levels of EGR has been well documented to decrease fuel consumption and reduce emissions of spark ignition engines. But there are also many limitations associated with this technology like EGR control and tolerance, which can reduce the potential efficiency improvements. A new concept called D-EGR has been presented in which the exhaust from a sub group of power cylinders is channeled back to the intake of all the cylinders. In this literature review both experimental and numerical analysis of this technology is shown. In the former case experiments were performed on 2.0 L PFI engine with gasoline as a fuel in part and high load conditions and the results show that at part loads the D-EGR engine can lead to lower Brake Specific Fuel Consumption, lower HC and CO emissions and higher brake thermal efficiency. At high load operations the results show improved combustion stability and superior knock tolerance. In the numerical studies it shows comparable thermal efficiency with conventional SI engines and reduction in NOX emissions.

  10. Interactions of multiple spark-generated bubbles with phase differences

    Science.gov (United States)

    Fong, Siew Wan; Adhikari, Deepak; Klaseboer, Evert; Khoo, Boo Cheong

    2009-04-01

    This paper aims to study the complex interaction between multiple bubbles, and to provide a summary and physical explanation of the phenomena observed during the interaction of two bubbles. High-speed photography is utilized to observe the experiments involving multiple spark-generated bubbles. Numerical simulations corresponding to the experiments are performed using the Boundary Element Method (BEM). The bubbles are typically between 3 and 5 mm in radius and are generated either in-phase (at the same time) or with phase differences. Complex phenomena are observed such as bubble splitting, and high-speed jetting inside a bubble caused by another collapsing bubble nearby (termed the ‘catapult’ effect). The two-bubble interactions are broadly classified in a graph according to two parameters: the relative inter-bubble distance and the phase difference (a new parameter introduced). The BEM simulations provide insight into the physics, such as bubble shape changes in detail, and jet velocities. Also presented in this paper are the experimental results of three bubble interactions. The interesting and complex observations of multiple bubble interaction are important for a better understanding of real life applications in medical ultrasonic treatment and ultrasonic cleaning. Many of the three bubble interactions can be explained by isolating bubble pairs and classifying their interaction according to the graph for the two bubble case. This graph can be a useful tool to predict the behavior of multiple bubble interactions.

  11. Nanostructured CoSi Obtained by Spark Plasma Sintering

    Science.gov (United States)

    Longhin, Marco; Viennois, Romain; Ravot, Didier; Robin, Jean-Jacques; Villeroy, Benjamin; Vaney, Jean-Baptiste; Candolfi, Christophe; Lenoir, Bertrand; Papet, Philippe

    2015-06-01

    Cobalt monosilicide is a cheap, environmentally friendly thermoelectric material for medium temperatures (200-700°C). While its power factor is similar to the state-of-the-art thermoelectric materials, its thermal conductivity is too large to reach high ZT values. Nanostructuring might be an interesting strategy to reduce the phonon mean free path thereby improving the thermoelectric performance. In this paper, we report on a 35% reduction of the thermal conductivity of n-type CoSi by a nanostructuring approach. CoSi nanostructured powders were synthesized by arc melting, followed by 4° h mechanical milling. By optimizing the spark plasma sintering thermal and pressure cycle, pellets with 5â€"10% porosity were obtained. During sintering, a small amount of Co2Si extra phase appeared and grains coarsened. After sintering, the pellets remained nanostructured, with an averaged grain size of 70 nm. The reduction of thermal conductivity is ascribed to a decrease in both the electronic and lattice contributions. The former is directly related to a decrease in the electrical conductivity, which appears to be the limiting factor preventing nanostructured CoSi from reaching enhanced thermoelectric performances.

  12. Fuzzy Fireworks Algorithm Based on a Sparks Dispersion Measure

    Directory of Open Access Journals (Sweden)

    Juan Barraza

    2017-07-01

    Full Text Available The main goal of this paper is to improve the performance of the Fireworks Algorithm (FWA. To improve the performance of the FWA we propose three modifications: the first modification is to change the stopping criteria, this is to say, previously, the number of function evaluations was utilized as a stopping criteria, and we decided to change this to specify a particular number of iterations; the second and third modifications consist on introducing a dispersion metric (dispersion percent, and both modifications were made with the goal of achieving dynamic adaptation of the two parameters in the algorithm. The parameters that were controlled are the explosion amplitude and the number of sparks, and it is worth mentioning that the control of these parameters is based on a fuzzy logic approach. To measure the impact of these modifications, we perform experiments with 14 benchmark functions and a comparative study shows the advantage of the proposed approach. We decided to call the proposed algorithms Iterative Fireworks Algorithm (IFWA and two variants of the Dispersion Percent Iterative Fuzzy Fireworks Algorithm (DPIFWA-I and DPIFWA-II, respectively.

  13. Reactive Spark Plasma Sintering: Successes and Challenges of Nanomaterial Synthesis

    Directory of Open Access Journals (Sweden)

    Dina V. Dudina

    2013-01-01

    Full Text Available Spark plasma sintering (SPS, initially developed as an advanced sintering technique for consolidating nanopowders into nanostructured bulk materials, has been recently looked at in much broader perspective and gained a strong reputation of a versatile method of solid state processing of metals, ceramics, and composites. The powders in the SPS-dies experience the action of pulsed electric current and uniaxial pressure; they are heated at very high rates unachievable in furnace heating and sintered within shorter times and at lower temperatures than in conventional methods. The principle of SPS and convenient design of the facilities make it attractive for conducting solid state synthesis. In this paper, based on our own results and the literature data, we analyze the microstructure formation of the products of chemical reactions occurring in the SPS in an attempt to formulate the requirements to the microstructure parameters of reactant mixtures and SPS conditions that should be fulfilled in order to produce a nanostructured material. We present successful syntheses of nanostructured ceramics and metal matrix composite with nanosized reinforcements in terms of microstructure stability and attractive properties of the materials and discuss the challenges of making a dense nanostructured material when reaction and densification do not coincide during the SPS. In the final part of the paper, we provide an outlook on the further uses of reactive SPS in the synthesis of nanostructured materials.

  14. Consolidation of copper and aluminium powders by spark plasma sintering

    Science.gov (United States)

    Saiprasad, M.; Atchayakumar, R.; Thiruppathi, K.; Raghuraman, S.

    2016-09-01

    Processing in the powder metallurgy route has emerged as an economical process for the production of near net shaped components with a wide range of desired mechanical properties suitable for various applications of industrial needs. This research work was conducted with an objective of studying the improvisation of density and hardness of Copper-Aluminium alloy prepared by spark plasma sintering. Cu-Al alloy with a composition of 95% copper and 5% aluminium was prepared by SPS process. SPS is a low voltage, DC pulse current activated, pressure-assisted sintering, which enables sintering at lower temperatures and shorter durations. The combination offered by Cu-Al alloy of high strength and high corrosion resistance results their applications under a wide variety of conditions. The density and hardness of the prepared sample were measured by conducting appropriate tests. Apparently, the values of hardness and density of the specimen prepared by SPS seemed to be better than that of conventional sintering. The experimental procedure, testing methodologies and analysis are presented.

  15. Ca2+ sparks act as potent regulators of excitation-contraction coupling in airway smooth muscle.

    Science.gov (United States)

    Zhuge, Ronghua; Bao, Rongfeng; Fogarty, Kevin E; Lifshitz, Lawrence M

    2010-01-15

    Ca2+ sparks are short lived and localized Ca2+ transients resulting from the opening of ryanodine receptors in sarcoplasmic reticulum. These events relax certain types of smooth muscle by activating big conductance Ca2+-activated K+ channels to produce spontaneous transient outward currents (STOCs) and the resultant closure of voltage-dependent Ca2+ channels. But in many smooth muscles from a variety of organs, Ca2+ sparks can additionally activate Ca2+-activated Cl(-) channels to generate spontaneous transient inward current (STICs). To date, the physiological roles of Ca2+ sparks in this latter group of smooth muscle remain elusive. Here, we show that in airway smooth muscle, Ca2+ sparks under physiological conditions, activating STOCs and STICs, induce biphasic membrane potential transients (BiMPTs), leading to membrane potential oscillations. Paradoxically, BiMPTs stabilize the membrane potential by clamping it within a negative range and prevent the generation of action potentials. Moreover, blocking either Ca2+ sparks or hyperpolarization components of BiMPTs activates voltage-dependent Ca2+ channels, resulting in an increase in global [Ca2+](i) and cell contraction. Therefore, Ca2+ sparks in smooth muscle presenting both STICs and STOCs act as a stabilizer of membrane potential, and altering the balance can profoundly alter the status of excitability and contractility. These results reveal a novel mechanism underlying the control of excitability and contractility in smooth muscle.

  16. A new spark detection system for the electrostatic septa of the SPS North (experimental) Area

    CERN Document Server

    Barlow, R A; Borburgh, J; Carlier, E; Chanavat, C; Fowler, T; Pinget, B

    2014-01-01

    Electrostatic septa (ZS) are used in the extraction of the particle beams from the CERN SPS to the North Area experimental zone. These septa employ high electric fields, generated from a 300 kV power supply, and are particularly prone to internal sparking around the cathode structure. This sparking degrades the electric field quality, consequently affecting the extracted beam, vacuum and equipment performance. To mitigate these effects, a Spark Detection System (SDS) has been realised, which is based on an industrial SIEMENS S7-400 programmable logic controller and deported Boolean processor modules interfaced through a PROFINET fieldbus. The SDS interlock logic uses a moving average spark rate count to determine if the ZS performance is acceptable. Below a certain spark rate it is probable that the ZS septa tank vacuum can recover, thus avoiding transition into a state where rapid degradation would occur. Above this level an interlock is raised and the high voltage is switched off. Additionally, all spark si...

  17. Experimental Investigation of Augmented Spark Ignition of a LO2/LCH4 Reaction Control Engine at Altitude Conditions

    Science.gov (United States)

    Kleinhenz, Julie; Sarmiento, Charles; Marshall, William

    2012-01-01

    The use of nontoxic propellants in future exploration vehicles would enable safer, more cost-effective mission scenarios. One promising green alternative to existing hypergols is liquid methane (LCH4) with liquid oxygen (LO2). A 100 lbf LO2/LCH4 engine was developed under the NASA Propulsion and Cryogenic Advanced Development project and tested at the NASA Glenn Research Center Altitude Combustion Stand in a low pressure environment. High ignition energy is a perceived drawback of this propellant combination; so this ignition margin test program examined ignition performance versus delivered spark energy. Sensitivity of ignition to spark timing and repetition rate was also explored. Three different exciter units were used with the engine s augmented (torch) igniter. Captured waveforms indicated spark behavior in hot fire conditions was inconsistent compared to the well-behaved dry sparks. This suggests that rising pressure and flow rate increase spark impedance and may at some point compromise an exciter s ability to complete each spark. The reduced spark energies of such quenched deliveries resulted in more erratic ignitions, decreasing ignition probability. The timing of the sparks relative to the pressure/flow conditions also impacted the probability of ignition. Sparks occurring early in the flow could trigger ignition with energies as low as 1 to 6 mJ, though multiple, similarly timed sparks of 55 to 75 mJ were required for reliable ignition. Delayed spark application and reduced spark repetition rate both correlated with late and occasional failed ignitions. An optimum time interval for spark application and ignition therefore coincides with propellant introduction to the igniter.

  18. Capacitor discharge engineering

    CERN Document Server

    Früngel, Frank B A

    1976-01-01

    High Speed Pulse Technology, Volume III: Capacitor Discharge Engineering covers the production and practical application of capacitor dischargers for the generation and utilization of high speed pulsed of energy in different forms. This nine-chapter volume discusses the principles of electric current, voltage, X-rays, gamma rays, heat, beams of electrons, neutrons and ions, magnetic fields, sound, and shock waves in gases and liquids. Considerable chapters consider the applications of capacitor discharges, such as impulse hardening of steel, ultrapulse welding of precision parts, X-ray flash t

  19. Plasma return current discharge

    International Nuclear Information System (INIS)

    Mangano, J.A.; Hsia, J.; Jacob, J.H.; Srivastava, B.N.

    1978-01-01

    A discharge technique based on the use of an electron-beam-induced plasma return current to produce and heat large-volume plasmas is described. The results of discharge studies using this technique in attachment-dominated mixtures are presented. The results are found to be adequately described by a simple theory. The electron attachment rate by F 2 inferred from these measurements agrees well with those of other workers. KrF laser action at 248 nm is reported in return-current discharge-excited mixtures of F 2 /Kr/He

  20. Filament Discharge Phenomena in Fingerprint Acquisition by Dielectric Barrier Discharge

    International Nuclear Information System (INIS)

    Weng Ming; Xu Weijun; Liu Qiang

    2007-01-01

    In this paper, the dielectric barrier discharge fingerprint acquisition technique is introduced. The filament discharge phenomena were observed in the process of fingerprint acquisition. The filament discharge reduced the quality of fingerprint images. Obviously, it was necessary to eliminate streamer discharges in order to get good fingerprint images. The streamer discharge was considered to be the cause of the filament discharge in the experiment. The relationship between the critical electric field and the discharge gap was calculated with the Raether's model of streamer discharge. The calculated results and our experiment proved that it would be difficult for the streamer discharge to occur when the discharge gap was narrow. With a narrow discharge gap, the discharge was homogeneous, and the fingerprint images were clear and large in area. The images obtained in the experiment are very suitable for fingerprint identification as they contain more information

  1. Discharge plasmas as EUV Sources for Future Micro Lithography

    Science.gov (United States)

    Kruecken, Thomas

    2007-08-01

    Future extreme ultraviolet (EUV) lithography will require very high radiation intensities in a narrow wavelength range around 13.5 nm, which is most efficiently emitted as line radiation by highly ionized heavy particles. Currently the most intense EUV sources are based on xenon or tin gas discharges. After having investigated the limits of a hollow cathode triggered xenon pinch discharge Philips Extreme UV favors a laser triggered tin vacuum spark discharge. Plasma and radiation properties of these highly transient discharges will be compared. Besides simple MHD-models the ADAS software package has been used to generate important atomic and spectral data of the relevant ion stages. To compute excitation and radiation properties, collisional radiative equilibria of individual ion stages are computed. For many lines opacity effects cannot be neglected. In the xenon discharges the optical depths allow for a treatment based on escape factors. Due to the rapid change of plasma parameters the abundancies of the different ionization stages must be computed dynamically. This requires effective ionization and recombination rates, which can also be supplied by ADAS. Due to very steep gradients (up to a couple orders of magnitude per mm) the plasma of tin vacuum spark discharges is very complicated. Therefore we shall describe here only some technological aspects of our tin EUV lamp: The electrode system consists of two rotating which are pulled through baths of molten tin such that a tin film remains on their surfaces. With a laser pulse some tin is ablated from one of the wheels and travels rapidly through vacuum towards the other rotating wheel. When the tin plasma reaches the other electrodes it ignites and the high current phase starts, i.e. the capacitor bank is unloaded, the plasma is pinched and EUV is radiated. Besides the good spectral properties of tin this concept has some other advantages: Erosion of electrodes is no severe problem as the tin film is

  2. SciSpark's SRDD : A Scientific Resilient Distributed Dataset for Multidimensional Data

    Science.gov (United States)

    Palamuttam, R. S.; Wilson, B. D.; Mogrovejo, R. M.; Whitehall, K. D.; Mattmann, C. A.; McGibbney, L. J.; Ramirez, P.

    2015-12-01

    Remote sensing data and climate model output are multi-dimensional arrays of massive sizes locked away in heterogeneous file formats (HDF5/4, NetCDF 3/4) and metadata models (HDF-EOS, CF) making it difficult to perform multi-stage, iterative science processing since each stage requires writing and reading data to and from disk. We have developed SciSpark, a robust Big Data framework, that extends ApacheTM Spark for scaling scientific computations. Apache Spark improves the map-reduce implementation in ApacheTM Hadoop for parallel computing on a cluster, by emphasizing in-memory computation, "spilling" to disk only as needed, and relying on lazy evaluation. Central to Spark is the Resilient Distributed Dataset (RDD), an in-memory distributed data structure that extends the functional paradigm provided by the Scala programming language. However, RDDs are ideal for tabular or unstructured data, and not for highly dimensional data. The SciSpark project introduces the Scientific Resilient Distributed Dataset (sRDD), a distributed-computing array structure which supports iterative scientific algorithms for multidimensional data. SciSpark processes data stored in NetCDF and HDF files by partitioning them across time or space and distributing the partitions among a cluster of compute nodes. We show usability and extensibility of SciSpark by implementing distributed algorithms for geospatial operations on large collections of multi-dimensional grids. In particular we address the problem of scaling an automated method for finding Mesoscale Convective Complexes. SciSpark provides a tensor interface to support the pluggability of different matrix libraries. We evaluate performance of the various matrix libraries in distributed pipelines, such as Nd4jTM and BreezeTM. We detail the architecture and design of SciSpark, our efforts to integrate climate science algorithms, parallel ingest and partitioning (sharding) of A-Train satellite observations from model grids. These

  3. Nanosecond Repetitively Pulsed Discharges in Air at Atmospheric Pressure -- Experiment and Theory of Regime Transitions

    Science.gov (United States)

    Pai, David; Lacoste, Deanna; Laux, Christophe

    2009-10-01

    In atmospheric pressure air preheated from 300 to 1000 K, the Nanosecond Repetitively Pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and inter-electrode gap distance) of each discharge regime. Notably, there is a minimum gap distance for the existence of the glow regime that increases with decreasing gas temperature. A theory is developed to describe the Corona-to-Glow (C-G) and Glow-to-Spark (G-S) transitions for NRP discharges. The C-G transition is shown to depend on the Avalanche-to-Streamer Transition (AST) as well as the electric field strength in the positive column. The G-S transition is due to the thermal ionization instability. The minimum gap distance for the existence of the glow regime can be understood by considering that the applied voltage of the AST must be lower than that of the thermal ionization instability. This is a previously unknown criterion for generating glow discharges, as it does not correspond to the Paschen minimum or to the Meek-Raether criterion.

  4. The effect of the configuration of a single electrode corona discharge on its acoustic characteristics

    Science.gov (United States)

    Zhu, Xinlei; Zhang, Liancheng; Huang, Yifan; Wang, Jin; Liu, Zhen; Yan, Keping

    2017-07-01

    A new sparker system based on pulsed spark discharge with a single electrode has already been utilized for oceanic seismic exploration. However, the electro-acoustic energy efficiency of this system is lower than that of arc discharge based systems. A simple electrode structure was investigated in order to improve the electro-acoustic energy efficiency of the spark discharge. Experiments were carried out on an experimental setup with discharge in water driven by a pulsed power source. The voltage-current waveform, acoustic signal and bubble oscillation were recorded when the relative position of the electrode varied. The electro-acoustic energy efficiency was also calculated. The load voltage had a saltation for the invaginated electrode tip, namely an obvious voltage remnant. The more the electrode tip was invaginated, the larger the pressure peaks and first period became. The results show that electrode recessing into the insulating layer is a simple and effective way to improve the electro-acoustic energy efficiency from 2% to about 4%.

  5. Implantable cardioverter defibrillator - discharge

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000108.htm Implantable cardioverter defibrillator - discharge To use the sharing features on this page, please enable JavaScript. An implantable cardioverter-defibrillator (ICD) is a device that detects a life- ...

  6. Hypospadias repair - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000158.htm Hypospadias repair - discharge To use the sharing features on this page, please enable JavaScript. Your child had hypospadias repair to fix a birth defect in which ...

  7. Concussion - child - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000125.htm Concussion in children - discharge To use the sharing features ... enable JavaScript. Your child was treated for a concussion . This is a mild brain injury that can ...

  8. Urethral discharge culture

    Science.gov (United States)

    ... Genital exudate culture; Culture - genital discharge or exudate; Urethritis - culture ... Augenbraun MH, McCormack WM. Urethritis. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases . 8th ed. ...

  9. Thyroid gland removal - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000293.htm Thyroid gland removal - discharge To use the sharing features ... surgery. This will make your scar show less. Thyroid Hormone Replacement You may need to take thyroid ...

  10. Atrial fibrillation - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000237.htm Atrial fibrillation - discharge To use the sharing features on this ... have been in the hospital because you have atrial fibrillation . This condition occurs when your heart beats faster ...

  11. Asthma - child - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000001.htm Asthma - child - discharge To use the sharing features on this ... care for your child. Take Charge of Your Child's Asthma at Home Make sure you know the asthma ...

  12. Small bowel resection - discharge

    Science.gov (United States)

    ... Ileostomy and your diet Ileostomy - caring for your stoma Ileostomy - changing your pouch Ileostomy - discharge Ileostomy - what to ask your doctor Low-fiber diet Surgical wound care - open Types of ileostomy Wet-to-dry dressing ...

  13. Kidney stones - lithotripsy - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000136.htm Kidney stones and lithotripsy - discharge To use the sharing features on this page, please enable JavaScript. A kidney stone is a solid mass made up of tiny ...

  14. Chest radiation - discharge

    Science.gov (United States)

    Radiation - chest - discharge; Cancer - chest radiation; Lymphoma - chest radiation ... When you have radiation treatment for cancer, your body goes through changes. About 2 weeks after your first treatment: It may be hard ...

  15. Breast radiation - discharge

    Science.gov (United States)

    Radiation - breast - discharge ... away around 4 to 6 weeks after the radiation treatment is over. You may notice changes in ... breast looks or feels (if you are getting radiation after a lumpectomy). These changes include: Soreness or ...

  16. Brain radiation - discharge

    Science.gov (United States)

    Radiation - brain - discharge; Cancer-brain radiation; Lymphoma - brain radiation; Leukemia - brain radiation ... Decadron) while you are getting radiation to the brain. It may make you hungrier, cause leg swelling ...

  17. Epilepsy - children - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000127.htm Epilepsy in children - discharge To use the sharing features ... this page, please enable JavaScript. Your child has epilepsy . People with epilepsy have seizures. A seizure is ...

  18. Epilepsy or seizures - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000128.htm Epilepsy or seizures - discharge To use the sharing features on this page, please enable JavaScript. You have epilepsy . People with epilepsy have seizures. A seizure is ...

  19. Multiple sclerosis - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000129.htm Multiple sclerosis - discharge To use the sharing features on this ... Your doctor has told you that you have multiple sclerosis (MS). This disease affects the brain and spinal ...

  20. Pneumonia - adults - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000017.htm Pneumonia in adults - discharge To use the sharing features on this page, please enable JavaScript. You have pneumonia, which is an infection in your lungs. In ...

  1. Pneumonia - children - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000011.htm Pneumonia in children - discharge To use the sharing features ... this page, please enable JavaScript. Your child has pneumonia, which is an infection in the lungs. In ...

  2. Hip fracture - discharge

    Science.gov (United States)

    ... Philadelphia, PA: Elsevier; 2017:chap 55. Read More Broken bone Hip fracture surgery Hip pain Leg MRI scan Osteoporosis - overview Patient Instructions Getting your home ready - knee or hip surgery Osteomyelitis - discharge Review ...

  3. Lanthana-bearing nanostructured ferritic steels via spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Pasebani, Somayeh [Department of Chemical and Materials Engineering, University of Idaho, Moscow, ID 83844 (United States); Center for Advanced Energy Studies, Idaho Falls, ID 83401 (United States); Charit, Indrajit, E-mail: icharit@uidaho.edu [Department of Chemical and Materials Engineering, University of Idaho, Moscow, ID 83844 (United States); Center for Advanced Energy Studies, Idaho Falls, ID 83401 (United States); Wu, Yaqiao; Burns, Jatuporn; Allahar, Kerry N.; Butt, Darryl P. [Department of Materials Science and Engineering, Boise State University, Boise, ID 83725 (United States); Center for Advanced Energy Studies, Idaho Falls, ID 83401 (United States); Cole, James I. [Idaho National Laboratory, Idaho Falls, ID 83401 (United States); Center for Advanced Energy Studies, Idaho Falls, ID 83401 (United States); Alsagabi, Sultan F. [Department of Chemical and Materials Engineering, University of Idaho, Moscow, ID 83844 (United States); Center for Advanced Energy Studies, Idaho Falls, ID 83401 (United States)

    2016-03-15

    A lanthana-containing nanostructured ferritic steel (NFS) was processed via mechanical alloying (MA) of Fe-14Cr-1Ti-0.3Mo-0.5La{sub 2}O{sub 3} (wt.%) and consolidated via spark plasma sintering (SPS). In order to study the consolidation behavior via SPS, sintering temperature and dwell time were correlated with microstructure, density, microhardness and shear yield strength of the sintered specimens. A bimodal grain size distribution including both micron-sized and nano-sized grains was observed in the microstructure of specimens sintered at 850, 950 and1050 °C for 45 min. Significant densification occurred at temperatures greater than 950 °C with a relative density higher than 98%. A variety of nanoparticles, some enriched in Fe and Cr oxides and copious nanoparticles smaller than 10 nm with faceted morphology and enriched in La and Ti oxides were observed. After SPS at 950 °C, the number density of Cr–Ti–La–O-enriched nanoclusters with an average radius of 1.5 nm was estimated to be 1.2 × 10{sup 24} m{sup −3}. The La + Ti:O ratio was close to 1 after SPS at 950 and 1050 °C; however, the number density of nanoclusters decreased at 1050 °C. With SPS above 950 °C, the density improved but the microhardness and shear yield strength decreased due to partial coarsening of the grains and nanoparticles.

  4. Generation of a Social Network Graph by Using Apache Spark

    Directory of Open Access Journals (Sweden)

    Y. A. Belov

    2016-01-01

    Full Text Available We plan to create a method of clustering a social network graph. For testing the method there is a need to generate a graph similar in structure to existing social networks. The article presents an algorithm for the graph distributed generation. We took into account basic properties such as power-law distribution of the users communities number, dense intersections of the social networks and others. This algorithm also considers the problems that are present in similar works of other authors, for example, the multiple edges problem in the generation process. A special feature of the created algorithm is the implementation depending on the communities number parameter rather than on the connected users number as it is done in other works. It is connected with a peculiarity of progressing the existing social network structure. There are properties of its graph in the paper. We described a table containing the variables needed for the algorithm. A step-by-step generation algorithm was compiled. Appropriate mathematical parameters were calculated for it. A generation is performed in a distributed way by Apache Spark framework. It was described in detail how the tasks division with the help of this framework runs. The Erdos-Renyi model for random graphs is used in the algorithm. It is the most suitable and easy one to implement. The main advantages of the created method are the small amount of resources in comparison with other similar generators and execution speed. Speed is achieved through distributed work and the fact that in any time network users have their own unique numbers and are ordered by these numbers, so there is no need to sort them out. The designed algorithm will promote not only the efficient clustering method creation. It can be useful in other development areas connected, for example, with the social networks search engines.

  5. Pseudo-spark switch (PSS) characteristics under different operation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hamad, B. H., E-mail: dr.bassmahussain@gmail.com; Ahmad, A. K., E-mail: ahmad.kamal@sc.nahrainuniv.edu.iq [College of Science, Al Nahrain University, Jadria, Baghdad (Iraq); Lateef, K. H., E-mail: kamalhlatif@yahoo.com [Ministry of Science and Technology, Jadria, Baghdad (Iraq)

    2016-08-15

    The present paper concentrates on the characteristics of the pseudospark switch (PSS) designed in a previous work. The special characteristics of PSS make it a replacement for other high voltage switches such as thyratrons and ordinary high-pressure spark gaps. PSS is characterized by short rise time and small jitter time. The pseudo park chamber consists of two hollow cylindrical electrodes made of a stainless steel material (type 306L) separated by an insulator. The insulator used in our design is a glazed ceramic 70 mm in diameter and 3.5 mm in thickness. A PSS with an anode voltage of 29.2 kV, and a current of 3.6 kA and 11 ns rise time was achieved and used successfully at a repetition rate of about 2.2 kHz. A simple trigger circuit designed, built, and used effectively reaching more than 1.56 kV trigger pulse which is sufficient to ignite the argon gas inside the cathode to cause a breakdown. A non-inductive dummy load is designed to be a new technique to find the accurate value of the PSS inductance. A jitter time of ±10 ns pulses is observed to occur in a reliable manner for more than 6 h of continuous operation. In this research, the important parameters of this switch like rise time, peak current, and anode voltage were studied at various values of charging capacitance. The lifetime of this system is depending on the kind of the electrode material and on the type of insulation material in the main gap of the pseudospark switch.

  6. Discharge lamp technologies

    Energy Technology Data Exchange (ETDEWEB)

    Dakin, J. [GE Lighting, Cleveland, OH (United States)

    1994-12-31

    This talk is an overview of discharge lamp technology commonly employed in general lighting, with emphasis on issues pertinent to lighting for plant growth. Since the audience is primarily from the plant growth community, and this begins the light source part of the program, we will start with a brief description of the discharge lamps. Challenges of economics and of thermal management make lamp efficiency a prime concern in controlled environment agriculture, so we will emphasize science considerations relating to discharge lamp efficiency. We will then look at the spectra and ratings of some representative lighting products, and conclude with a discussion of technological advance. A general overview of discharge lighting technology can be found in the book of Waymouth (1971). A recent review of low pressure lighting discharge science is found in Dakin (1991). The pioneering paper of Reiling (1964) provides a good introduction to metal halide discharges. Particularly relevant to lighting for plant growth, a recent and thorough treatment of high pressure Na lamps is found in the book by deGroot and vanVliet (1986). Broad practical aspects of lighting application are thoroughly covered in the IES Lighting Handbook edited by Kaufman (1984).

  7. Chaos in gas discharges

    International Nuclear Information System (INIS)

    Piel, A.

    1993-01-01

    Many gas discharges exhibit natural oscillations which undergo a transition from regular to chaotic behavior by changing an experimental parameter or by applying external modulation. Besides several isolated investigations, two classes of discharge phenomena have been studied in more detail: ionization waves in medium pressure discharges and potential relaxation oscillations in filament cathode discharges at very low pressure. The latter phenomenon will be discussed by comparing experimental results from different discharge arrangements with particle-in-cell simulations and with a model based on the van-der-Pol equation. The filament cathode discharge has two stable modes of operation: the low current anode-glow-mode and the high current temperature-limited-mode, which form the hysteresis curve in the I(U) characteristics. Close to the hysteresis point of the AGM periodic relaxation oscillations occur. The authors demonstrate that the AGM can be understood by ion production in the anode layer, stopping of ions by charge exchange, and trapping in the virtual cathode around the filament. The relaxation oscillations consist of a slow filling phase and a rapid phase that invokes formation of an unstable double-layer, current-spiking, and ion depletion from the cathodic plasma. The relaxation oscillations can be mode-locked by external modulation. Inside a mode-locked state, a period doubling cascade is observed at high modulation degree

  8. Identifying discharge practice training needs.

    Science.gov (United States)

    Lees, L; Emmerson, K

    A training needs analysis tool was developed to identify nurses' discharge training needs and to improve discharge practice. The tool includes 49 elements of discharge practice subdivided into four areas: corporate, operational, clinical and nurse-led discharge. The tool was disseminated to 15 wards on two hospital sites with assistance from the practice development team. Analysis of discharge training is important to assess discharge training needs and to identify staff who may assist with training.

  9. CORONA DISCHARGE IGNITION FOR ADVANCED STATIONARY NATURAL GAS ENGINES

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Paul D. Ronney

    2003-09-12

    An ignition source was constructed that is capable of producing a pulsed corona discharge for the purpose of igniting mixtures in a test chamber. This corona generator is adaptable for use as the ignition source for one cylinder on a test engine. The first tests were performed in a cylindrical shaped chamber to study the characteristics of the corona and analyze various electrode geometries. Next a test chamber was constructed that closely represented the dimensions of the combustion chamber of the test engine at USC. Combustion tests were performed in this chamber and various electrode diameters and geometries were tested. The data acquisition and control system hardware for the USC engine lab was updated with new equipment. New software was also developed to perform the engine control and data acquisition functions. Work is underway to design a corona electrode that will fit in the new test engine and be capable igniting the mixture in one cylinder at first and eventually in all four cylinders. A test engine was purchased for the project that has two spark plug ports per cylinder. With this configuration it will be possible to switch between corona ignition and conventional spark plug ignition without making any mechanical modifications.

  10. Internal combustion engines a detailed introduction to the thermodynamics of spark and compression ignition engines, their design and development

    CERN Document Server

    Benson, Rowland S

    1979-01-01

    Internal Combustion of Engines: A Detailed Introduction to the Thermodynamics of Spark and Compression Ignition Engines, Their Design and Development focuses on the design, development, and operations of spark and compression ignition engines. The book first describes internal combustion engines, including rotary, compression, and indirect or spark ignition engines. The publication then discusses basic thermodynamics and gas dynamics. Topics include first and second laws of thermodynamics; internal energy and enthalpy diagrams; gas mixtures and homocentric flow; and state equation. The text ta

  11. Characterization of Erosion and Failure Processes of Spark Plugs After Field Service in Natural Gas Engines

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Hua-Tay [ORNL; Brady, Michael P [ORNL; Richards, Roger K [ORNL; Layton, David [National Transportation Research Center (NTRC)

    2005-01-01

    Microstructural and optical spectroscopic analyses were carried out on as-received and used spark plugs after field service in natural gas (NG) reciprocating engines. The objective of this work was to examine the corrosion and erosion mechanisms of natural gas engine spark plug as well as identify the primary life limiting processes during field operation. The optical emission spectroscopic analysis showed a strong Ca signal in the exposed spark plugs and scanning electron microscopy showed substantial formation of Ca-enriched glassy oxide phase(s) on the electrode surfaces. In addition, intergranular cracking was observed in the subsurface region of both iridium (Ir) and platinum-tungsten (Pt-W) alloy electrode insert tips. The coalescence and subsequent growth of these cracks would accelerate the wear of the electrodes and shorten the lifetime of the spark plugs. Also, extensive internal oxidation and subsequent crack generation occurred along the interface between Ni-base alloy electrode and Pt-W alloy tip insert during field service, which would result in substantial degradation in the ignitability and performance of the electrodes, and thus spark plug failure.

  12. THE EFFECT OF COMPRESSION RATIO VARIATIONS ON THE ENGINE PERFORMANCE PARAMETRES IN SPARK IGNITION ENGINES

    Directory of Open Access Journals (Sweden)

    Yakup SEKMEN

    2005-01-01

    Full Text Available Performance of the spark ignition engines may be increased by changing the geometrical compression ratio according to the amount of charging in cylinders. The designed geometrical compression ratio can be realized as an effective compression ratio under the full load and full open throttle conditions since the effective compression ratio changes with the amount of charging into the cylinder in spark ignition engines. So, this condition of the spark ignition engines forces designers to change their geometrical compression ratio according to the amount of charging into the cylinder for improvement of performance and fuel economy. In order to improve the combustion efficiency, fuel economy, power output, exhaust emissions at partial loads, compression ratio must be increased; but, under high load and low speed conditions to prevent probable knock and hard running the compression ratio must be decreased gradually. In this paper, relation of the performance parameters to compression ratio such as power, torque, specific fuel consumption, cylindir pressure, exhaust gas temperature, combustion chamber surface area/volume ratio, thermal efficiency, spark timing etc. in spark ignition engines have been investigated and using of engines with variable compression ratio is suggested to fuel economy and more clear environment.

  13. Synthesis and characterization of aluminium–alumina micro- and nano-composites by spark plasma sintering

    International Nuclear Information System (INIS)

    Dash, K.; Chaira, D.; Ray, B.C.

    2013-01-01

    Graphical abstract: The evolution of microstructure by varying the particle size of reinforcement in the matrix employing spark plasma sintering has been demonstrated here in Al–Al 2 O 3 system. An emphasis has been laid on varying the reinforcement particle size and evaluating the microstructural morphologies and their implications on mechanical performance of the composites. Nanocomposites of 0.5, 1, 3, 5, 7 volume % alumina (average size 2 O 3 micro- and nano-composites fabricated by spark plasma sintering. • Better matrix-reinforcement integrity in nanocomposites than microcomposites. • Spark plasma sintering method results in higher density and hardness values. • High density and hardness values of nanocomposites than microcomposites. • High dislocation density in spark plasma sintered Al–Al 2 O 3 composites. - Abstract: In the present study, an emphasis has been laid on evaluation of the microstructural morphologies and their implications on mechanical performance of the composites by varying the reinforcement particle size. Nanocomposites of 0.5, 1, 3, 5, 7 volume % alumina (average size 2 O 3 nancomposites respectively. Spark plasma sintering imparts enhanced densification and matrix-reinforcement proximity which have been corroborated with the experimental results

  14. SparkBWA: Speeding Up the Alignment of High-Throughput DNA Sequencing Data.

    Directory of Open Access Journals (Sweden)

    José M Abuín

    Full Text Available Next-generation sequencing (NGS technologies have led to a huge amount of genomic data that need to be analyzed and interpreted. This fact has a huge impact on the DNA sequence alignment process, which nowadays requires the mapping of billions of small DNA sequences onto a reference genome. In this way, sequence alignment remains the most time-consuming stage in the sequence analysis workflow. To deal with this issue, state of the art aligners take advantage of parallelization strategies. However, the existent solutions show limited scalability and have a complex implementation. In this work we introduce SparkBWA, a new tool that exploits the capabilities of a big data technology as Spark to boost the performance of one of the most widely adopted aligner, the Burrows-Wheeler Aligner (BWA. The design of SparkBWA uses two independent software layers in such a way that no modifications to the original BWA source code are required, which assures its compatibility with any BWA version (future or legacy. SparkBWA is evaluated in different scenarios showing noticeable results in terms of performance and scalability. A comparison to other parallel BWA-based aligners validates the benefits of our approach. Finally, an intuitive and flexible API is provided to NGS professionals in order to facilitate the acceptance and adoption of the new tool. The source code of the software described in this paper is publicly available at https://github.com/citiususc/SparkBWA, with a GPL3 license.

  15. Sparking connections: An exploration of adolescent girls' relationships with science

    Science.gov (United States)

    Wheeler, Kathryn A.

    Despite progress in narrowing the gender gap, fewer women than men pursue science careers. Adolescence is a critical age when girls' science interest is sparked or smothered. Prior research provides data on who drops out of the "science pipeline" and when, but few studies examine why and how girls disconnect from science. This thesis is an in-depth exploratory study of adolescent girls' relationships with science based on a series of interviews with four middle-class Caucasian girls---two from public schools, two homeschooled. The girls' stones about their experiences with, feelings about, and perspectives on science, the science process, and their science learning environments are examined with a theoretical and analytic approach grounded in relational psychology. The potential link between girls' voices and their involvement in science is investigated. Results indicate that girls' relationships with science are multitiered. Science is engaging and familiar in the sense that girls are curious about the world, enjoy learning about scientific phenomena, and informally use science in their everyday fives. However, the girls in this study differentiated between the science they do and the field of science, which they view as a mostly male endeavor (often despite real life experiences to the contrary) that uses rather rigid methods to investigate questions of limited scope and interest. In essence, how these girls defined science defined their relationship with science: those with narrow conceptions of science felt distant from it. Adolescent girls' decreased involvement in science activities may be a relational act---a move away from a patriarchical process, pedagogy, and institution that does not resonate with their experiences, questions, and learning styles. Girls often feel like outsiders to science; they resist considering science careers when they have concerns that implicitly or explicitly, doing so would involve sacrificing their knowledge, creativity, or

  16. Computerized precision control of a synchronous high voltage discharge switch for the beam separation system of the LEP e+/e- collider

    International Nuclear Information System (INIS)

    Dieperink, J.H.; Finnigan, A.; Kalbreier, W.; Keizer, R.L.; Laffin, M.; Mertens, V.

    1989-01-01

    Electrostatic separators are used to separate the beams in LEP. The counter-rotating beams are eventually brought into collision in the four low beta insertions, using switches to discharge simultaneously four high voltage (HV) circuits. Each switch consists of four spark gaps mounted in a pressure vessel. A reduction of the gap widths below the self ignition instance by electric motors results in the initiation of the discharges. Synchronization is ensured by the electrical coupling of the electrodes connected to the ground. The design and performance of the computerized precision control of the discharge switch are described. The dynamic characteristics of the prototype switch are also presented. 5 refs., 5 figs

  17. Fast capillary discharge facility CAPEX-U as a source of the soft X-ray radiation

    Czech Academy of Sciences Publication Activity Database

    Frolov, Oleksandr; Koláček, Karel; Schmidt, Jiří; Štraus, Jaroslav; Prukner, Václav

    2007-01-01

    Roč. 52, č. 16 (2007), s. 295-295 ISSN 0003-0503. [Annual Meeting of the Division of Plasma Physics/49th./. Orlando , Florida, 12.11.2007-16.11.2007] R&D Projects: GA ČR GA202/06/1324; GA AV ČR KJB100430702; GA AV ČR KAN300100702; GA MŠk 1P04LA235 Institutional research plan: CEZ:AV0Z20430508 Keywords : Capillary discharge * x-ray * laser * laser-triggered * spark gap * breakdown * plasma Subject RIV: BL - Plasma and Gas Discharge Physics http://meetings.aps.org/Meeting/DPP07/Content/901

  18. Oil based mud discharges

    International Nuclear Information System (INIS)

    Tiesma, R.

    1996-01-01

    The intensive use of oil based muds by the offshore oil and gas industry during the 1980s has caused considerable contamination around drilling sites. A recent investigation on the Norwegian continental shelf indicates that the situation is much worse than previously thought. This material suggests that oil pollution of this kind could be damaging the North Sea's endangered fish stocks, including cod, haddock and plaice. The amount of oil discharged in the UK sector is many times higher than in the other sectors, suggesting that the problem there may be even more serious. The amount discharged in the Dutch and Norwegian sectors are comparable. (author)

  19. [Diagnosis of vaginal discharge].

    Science.gov (United States)

    Böcher, Sidsel; Helmig, Rikke Bek; Arpi, Magnus; Bjerrum, Lars

    2018-01-15

    Changes in vaginal discharge are often caused by imbalance in the vaginal microflora, and laboratory testing is usually of little use, as most microbes detected are commensals. In-office diagnosis in general practice using wet mount microscopy and Amsel criteria is helpful and often sufficient to ensure correct diagnosis and treatment. Laboratory testing of vaginal discharge should only be performed, if sexually transmitted disease is suspected, if there is treatment failure or inconclusive wet mount prior to gynaecological surgery, and in pregnant women with recurrent miscarriage or preterm birth.

  20. Red herring vaginal discharge.

    Science.gov (United States)

    Lee, Jun Hee; Pringle, Kirsty; Rajimwale, Ashok

    2013-09-18

    Labial hair tourniquet syndrome is a rare condition that can be easily misdiagnosed and ultimately lead to irreversible damage. An 11-year-old premenarche girl presented with a 5-day history of pain and swelling in the labia with associated vaginal discharge. The general practitioner treated her with clotrimazole without improvement. On examination, there was an oedematous swelling of the right labia with a proximal hair tourniquet. Local anaesthetic was applied and the hair removed with forceps. There was instant relief of pain and the discharge stopped within 24 h. The patient was sent home with a course of antibiotics.

  1. Combustion process in a spark ignition engine: dynamics and noise level estimation.

    Science.gov (United States)

    Kaminski, T; Wendeker, M; Urbanowicz, K; Litak, G

    2004-06-01

    We analyze the experimental time series of internal pressure in a four cylinder spark ignition engine. In our experiment, performed for different spark advance angles, apart from the usual cyclic changes of engine pressure we observed additional oscillations. These oscillations are with longer time scales ranging from one to several hundred engine cycles depending on engine working conditions. Based on the pressure time dependence we have calculated the heat released per combustion cycle. Using the time series of heat release to calculate the correlation coarse-grained entropy we estimated the noise level for internal combustion process. Our results show that for a larger spark advance angle the system is more deterministic. (c) 2004 American Institute of Physics

  2. Development And Testing Of Biogas-Petrol Blend As An Alternative Fuel For Spark Ignition Engine

    Directory of Open Access Journals (Sweden)

    Awogbemi

    2015-08-01

    Full Text Available Abstract This research is on the development and testing of a biogas-petrol blend to run a spark ignition engine. A2080 ratio biogaspetrol blend was developed as an alternative fuel for spark ignition engine test bed. Petrol and biogas-petrol blend were comparatively tested on the test bed to determine the effectiveness of the fuels. The results of the tests showed that biogas petrol blend generated higher torque brake power indicated power brake thermal efficiency and brake mean effective pressure but lower fuel consumption and exhaust temperature than petrol. The research concluded that a spark ignition engine powered by biogas-petrol blend was found to be economical consumed less fuel and contributes to sanitation and production of fertilizer.

  3. ClimateSpark: An In-memory Distributed Computing Framework for Big Climate Data Analytics

    Science.gov (United States)

    Hu, F.; Yang, C. P.; Duffy, D.; Schnase, J. L.; Li, Z.

    2016-12-01

    Massive array-based climate data is being generated from global surveillance systems and model simulations. They are widely used to analyze the environment problems, such as climate changes, natural hazards, and public health. However, knowing the underlying information from these big climate datasets is challenging due to both data- and computing- intensive issues in data processing and analyzing. To tackle the challenges, this paper proposes ClimateSpark, an in-memory distributed computing framework to support big climate data processing. In ClimateSpark, the spatiotemporal index is developed to enable Apache Spark to treat the array-based climate data (e.g. netCDF4, HDF4) as native formats, which are stored in Hadoop Distributed File System (HDFS) without any preprocessing. Based on the index, the spatiotemporal query services are provided to retrieve dataset according to a defined geospatial and temporal bounding box. The data subsets will be read out, and a data partition strategy will be applied to equally split the queried data to each computing node, and store them in memory as climateRDDs for processing. By leveraging Spark SQL and User Defined Function (UDFs), the climate data analysis operations can be conducted by the intuitive SQL language. ClimateSpark is evaluated by two use cases using the NASA Modern-Era Retrospective Analysis for Research and Applications (MERRA) climate reanalysis dataset. One use case is to conduct the spatiotemporal query and visualize the subset results in animation; the other one is to compare different climate model outputs using Taylor-diagram service. Experimental results show that ClimateSpark can significantly accelerate data query and processing, and enable the complex analysis services served in the SQL-style fashion.

  4. Combustion visualization and experimental study on spark induced compression ignition (SICI) in gasoline HCCI engines

    International Nuclear Information System (INIS)

    Wang Zhi; He Xu; Wang Jianxin; Shuai Shijin; Xu Fan; Yang Dongbo

    2010-01-01

    Spark induced compression ignition (SICI) is a relatively new combustion control technology and a promising combustion mode in gasoline engines with high efficiency. SICI can be divided into two categories, SACI and SI-CI. This paper investigated the SICI combustion process using combustion visualization and engine experiment respectively. Ignition process of SICI was captured by high speed photography in an optical engine with different compression ratios. The results show that SICI is a combustion mode combined with partly flame propagation and main auto-ignition. The spark ignites the local mixture near spark electrodes and the flame propagation occurs before the homogeneous mixture is auto-ignited. The heat release from central burned zone due to the flame propagation increases the in-cylinder pressure and temperature, resulting in the unburned mixture auto-ignition. The SICI combustion process can be divided into three stages of the spark induced stage, the flame propagation stage and the compression ignition stage. The SICI combustion mode is different from the spark ignition (SI) knocking in terms of the combustion and emission characteristics. Furthermore, three typical combustion modes including HCCI, SICI, SI, were compared on a gasoline direct injection engine with higher compression ratio and switchable cam-profiles. The results show that SICI has an obvious combustion characteristic with two-stage heat release and lower pressure rise rate. The SICI combustion mode can be controlled by spark timings and EGR rates and utilized as an effective method for high load extension on the gasoline HCCI engine. The maximum IMEP of 0.82 MPa can be achieved with relatively low NO x emission and high thermal efficiency. The SICI combustion mode can be applied in medium-high load region for high efficiency gasoline engines.

  5. Discharges from nuclear power stations

    International Nuclear Information System (INIS)

    1991-02-01

    HM Inspectorate of Pollution commissioned, with authorising responsibilities in England and Wales, a study into the discharges of radioactive effluents from Nuclear Power Stations. The study considered arisings from nuclear power stations in Europe and the USA and the technologies to treat and control the radioactive discharges. This report contains details of the technologies used at many nuclear power stations to treat and control radioactive discharges and gives, where information was available, details of discharges and authorised discharge limits. (author)

  6. Sparking limits, cavity loading, and beam breakup instability associated with high-current rf linacs

    International Nuclear Information System (INIS)

    Faehl, R.J.; Lemons, D.S.; Thode, L.E.

    1982-01-01

    The limitations on high-current rf linacs due to gap sparking, cavity loading, and the beam breakup instability are studied. It appears possible to achieve cavity accelerating gradients as high as 35 MV/m without sparking. Furthermore, a linear analysis, as well as self-consistent particle simulations of a multipulsed 10 kA beam, indicated that only a negligible small fraction of energy is radiated into nonfundamental cavity modes. Finally, the beam breakup instability is analyzed and found to be able to magnify initial radial perturbations by a factor of no more than about 20 during the beam transit time through a 1 GeV accelerator

  7. Impulse tests on distribution transformers protected by means of spark gaps

    Energy Technology Data Exchange (ETDEWEB)

    Pykaelae, M.L.; Palva, V. [Helsinki Univ. of Technology, Otaniemi (Finland). High Voltage Institute; Niskanen, K. [ABB Corporate Research, Vaasa (Finland)

    1997-12-31

    Distribution transformers in rural networks have to cope with transient overvoltages, even with those caused by the direct lightning strokes to the lines. In Finland the 24 kV network conditions, such as wooden pole lines, high soil resistivity and isolated neutral network, lead into fast transient overvoltages. Impulse testing of pole-mounted distribution transformers ({<=} 200 kVA) protected by means of spark gaps were studied. Different failure detection methods were used. Results can be used as background information for standardization work dealing with distribution transformers protected by means of spark gaps. (orig.) 9 refs.

  8. Effect of electric spark pulses on surface layer structure of chromium monocrystals

    International Nuclear Information System (INIS)

    Evstyukhin, A.I.; Krapivka, N.A.; Barinov, I.P.

    1981-01-01

    Effect of electric spark pulses on the character of fracture of surface layers of chromium monocrystals during cutting in crystallographic planes (100), (110) and (111) is established. Crystallographical anisotropy of defect formation is determined and the value of defective layers during cutting in the above planes is found. A conclusion is made that cracks in chromium monocrystals of commercial grade during electric-spark cutting are formed in planes (100) and more seldom in (111) ones. A high-temperature annealing for the reduction of initial properties of chromium surface layers is suggested

  9. Effort on calibration of infrared spark ablation of copper with synthetic copper standards

    Energy Technology Data Exchange (ETDEWEB)

    Wienold, Julia, E-mail: julia.wienold@bam.de; Traub, Heike; Bresch, Harald; Seeger, Stefan; Recknagel, Sebastian; Kipphardt, Heinrich

    2011-06-15

    Two types of copper samples, compact certified copper reference materials and calibration samples prepared from liquid doped, pressed copper powders, were studied in terms of accuracy of obtained calibration functions originating from infrared spark ablation. Additionally, corresponding particle size distributions of the aerosols from infrared spark ablation were recorded. It is shown that the differences in quantification results, originating from the two sets of calibration functions, could not mainly be ascribed to different particle size distributions of the two copper sample types. Possible other causes, as different ablation rates, parts of melting and differences of the chemical constitutions of the two sample types were explored.

  10. Heart bypass surgery - discharge

    Science.gov (United States)

    ... trouble with short-term memory or feel confused ("fuzzy-headed") Be tired or not have much energy ... or a fever over 101°F (38.3°C). Alternative Names Off-pump coronary artery bypass - discharge; ...

  11. Electrical Discharge Machining.

    Science.gov (United States)

    Montgomery, C. M.

    The manual is for use by students learning electrical discharge machining (EDM). It consists of eight units divided into several lessons, each designed to meet one of the stated objectives for the unit. The units deal with: introduction to and advantages of EDM, the EDM process, basic components of EDM, reaction between forming tool and workpiece,…

  12. MANAGEMENT OF VAGINAL DISCHARGE

    African Journals Online (AJOL)

    Enrique

    , an oral antifungal should be used weekly, e.g. 100 mg flucona- zole.7. The discharge of candidiasis is curd- like and adherent due to direct hyphal invasion of epithelial tissues resulting in erythema of the vaginal epithelium. Clinical diagnosis ...

  13. Ulcerative colitis - discharge

    Science.gov (United States)

    ... doctor - child Diarrhea - what to ask your health care provider - adult Enteral nutrition - child - managing problems Gastrostomy feeding tube - bolus Ileostomy and your child Ileostomy and your diet Ileostomy - caring for your stoma Ileostomy - discharge Jejunostomy feeding tube Living with your ...

  14. Crohn disease - discharge

    Science.gov (United States)

    ... doctor - child Diarrhea - what to ask your health care provider - adult Enteral nutrition - child - managing problems Gastrostomy feeding tube - bolus Ileostomy and your child Ileostomy and your diet Ileostomy - caring for your stoma Ileostomy - discharge Jejunostomy feeding tube Living with your ...

  15. Cosmetic breast surgery - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000273.htm Cosmetic breast surgery - discharge To use the sharing features on this ... Editorial team. Related MedlinePlus Health Topics Plastic and Cosmetic Surgery Browse the Encyclopedia A.D.A.M., Inc. ...

  16. Effect of Spark Motor Program on the development of gross motor skills in intellectually disabled educable boys

    Directory of Open Access Journals (Sweden)

    Hashem Faal Moganloo

    2013-11-01

    Results: Spark Program caused significant changes in all the variables of the study, except speed and agility, in the experimental group after 24 sessions. The changes included: agility and speed (P=0.731, balance (P=0, strength (P=0.002, and bilateral coordination (P=0. Conclusion: Spark Motor Program can improve gross motor skills in intellectually disabled educable students.

  17. AN EXPERIMENTAL INVESTIGATION OF THE EFFECTS OF VARIABLE VALVE TIMING ON THE PERFORMANCE IN SPARK IGNITION ENGINE

    Directory of Open Access Journals (Sweden)

    Ali AKBAŞ

    2001-01-01

    Full Text Available In this study, an alternative prototype has been designed and constructed for variable valve timing systems which are used in spark ignition engines. The effects of intake valve timing and lift changing on engine performance have been investigated without changing the opening duration of the valves. A four stroke, single cylinder, spark ignition engine has been used for these experiments.

  18. Airborne laser-spark for ambient desorption/ionisation.

    Science.gov (United States)

    Bierstedt, Andreas; Riedel, Jens

    A novel direct sampling ionisation scheme for ambient mass spectrometry is presented. Desorption and ionisation are achieved by a quasi-continuous laser induced plasma in air. Since there are no solid or liquid electrodes involved the ion source does not suffer from chemical interferences or fatigue originating from erosive burning or from electrode consumption. The overall plasma maintains electro-neutrality, minimising charge effects and accompanying long term drift of the charged particles trajectories. In the airborne plasma approach the ambient air not only serves as the plasma medium but at the same time also slows down the nascent ions via collisional cooling. Ionisation of the analyte molecules does not occur in the plasma itself but is induced by interaction with nascent ionic fragments, electrons and/or far ultraviolet photons in the plasma vicinity. At each individual air-spark an audible shockwave is formed, providing new reactive species, which expands concentrically and, thus, prevents direct contact of the analyte with the hot region inside the plasma itself. As a consequence the interaction volume between plasma and analyte does not exceed the threshold temperature for thermal dissociation or fragmentation. Experimentally this indirect ionisation scheme is demonstrated to be widely unspecific to the chemical nature of the analyte and to hardly result in any fragmentation of the studied molecules. A vast ensemble of different test analytes including polar and non-polar hydrocarbons, sugars, low mass active ingredients of pharmaceuticals as well as natural biomolecules in food samples directly out of their complex matrices could be shown to yield easily accessible yet meaningful spectra. Since the plasma medium is humid air, the chemical reaction mechanism of the ionisation is likely to be similar to other ambient ionisation techniques. Wir stellen hier eine neue Ionisationsmethode für die Umgebungsionisation (ambient ionisation) vor. Sowohl die

  19. Method for improving the electrostatics perforation pattern using power controlled discharges

    Energy Technology Data Exchange (ETDEWEB)

    Garzon, C; Miranda, E; GarcIa-Garcia, J [Departament d' Enginyeria Electronica, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain); Martinez-Cisneros, C; Alonso, J, E-mail: carolina.garzon@uab.cat [Departament de Quimica Analitica, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain)

    2011-06-23

    The aims of this work are to show the influence of adding a series resistance at the output of a discharge generator circuit and to point out that this component can be used to control the spark energy in electrostatic perforation systems. Analysis of the experimental results reveals that there exists a close connection between the resistor value and the obtained perforation pattern both in hole density and size. The use of a series resistor has a strong influence on the material porosity, which is an important industrial parameter for assessing the pattern perforation quality.

  20. Target fabrication using laser and spark erosion machining

    International Nuclear Information System (INIS)

    Clement, X.; Coudeville, A.; Eyharts, P.; Perrine , J.P.; Rouillard, R.

    1981-11-01

    Lasers and E.D.M. (electrical discharge machining) are both extremely useful tools for machining the small targets needed in inertial confinement studies. Lasers are currently used in a wide range of target problems and it appears that E.D.M. has a still wider range of applications for plane and spherical targets. The problems of material deformation and tool breaking are practically eliminated as the electrode and the machined part are not in mechanical contact. In comparison with laser micromachining E.D.M. offers: larger versatility with the possibility of new developments and applications; higher production speed for thin conducting materials; lower initial and operating costs; the processes are well controlled, reproducible and can be easily automated; the operation is safe without the dangers associted with lasers

  1. Vessel Sewage Discharges: No-Discharge Zones (NDZs)

    Science.gov (United States)

    States may petition the EPA to establish areas, called no discharge zones (NDZs), where vessel sewage discharges are prohibited. This page describes how NDZs are designated, the types of designations, who enforces them, and how to comply.

  2. GASEOUS DISCHARGE DEVICE

    Science.gov (United States)

    Gow, J.D.

    1961-01-10

    An extremely compact two-terminal gaseous discharge device is described that is capable of producing neutrons in copious quantities, relatively high energy ions, intense x rays, and the like. Principal novelty resides in the provision of a crossed electric-magnetic field region in the discharge envelope that traps electrons and accelerates them to very high energies to provide an intense ionizing medium adjacent the anode of the device for ionizing gas therein with extremely high efficiency. In addition, the crossed-field trapping region holds the electrons close to the anode whereby the acceleration of ions to the cathode is not materially effected by the electron sheath and the ions assume substantially the full energy of the anodecathode potential drop. (auth)

  3. Discharge pulse phenomenology

    Science.gov (United States)

    Frederickson, A. R.

    1985-01-01

    A model was developed which places radiation induced discharge pulse results into a unified conceptual framework. Only two phenomena are required to interpret all space and laboratory results: (1) radiation produces large electrostatic fields inside insulators via the trapping of a net space charge density; and (2) the electrostatic fields initiate discharge streamer plasmas similar to those investigated in high voltage electrical insulation materials; these streamer plasmas generate the pulsing phenomena. The apparent variability and diversity of results seen is an inherent feature of the plasma streamer mechanism acting in the electric fields which is created by irradiation of the dielectrics. The implications of the model are extensive and lead to constraints over what can be done about spacecraft pulsing.

  4. Observation of X-rays from long laboratory negative discharge in STP air

    Science.gov (United States)

    Kochkin, Pavlo; van Deursen, A. P. J.; Ebert, Ute

    2014-05-01

    Pulses of x-rays emitted by lightning are one of the most intriguing among unsolved problem in physics of lightning. They have been detected from both - natural and rocket-triggered lightning. In natural lightning x-rays were detected during stepped leader process and later were associated with a single step. In triggered lighting x-rays were found to be originated from a tip of a dart leader that also possesses stepping propagation mechanism. Therefore, stepping mechanism is the key to understanding the x-ray pulses generated by lightning. Unfortunately, leader stepping mechanism itself is far from well understood. Negative long laboratory discharges also develop through a formation of a space stem/leader and they also generate bursts of x-ray radiation. In this study we investigate the development of a long negative laboratory spark in particular focusing on its x-ray emission. A 2 MV Marx generator delivers high-voltage standard lightning pulse with 1.2/50 microsec rise/fall time to a spark gap with conical electrodes. The distance between cone tips was varied between 1 m and 1.75 m. An upper voltage limit is set to about 1 MV level. The voltage is measured by capacitive high-voltage divider. Two Pearson 7427 current probes determine the currents through high-voltage and grounded electrodes. Two LaBr3 scintillator detectors were mounted in EMC-cabinets and recorded the x-rays. Picos4 Stanford Optics camera with intensified CCD is placed in 4 m distance from the spark gap and directed perpendicular to the spark plane. The camera allows us to make ns-fast images of pre-breakdown phenomena in controllable time. We discovered new details of space stem/leader formation and development in long laboratory sparks. The connection moment of positive part of the space stem/leader to negative high-voltage is accompanied by intense x-ray emission. Taking into account our previous study on positive discharge, we conclude that encounter between positive and negative streamers

  5. Monitoring of lightning discharge

    International Nuclear Information System (INIS)

    Grigor'ev, V.A.

    2001-01-01

    The paper presents a brief description of a lightning discharge recording system developed at the NPO 'Monitoring Techniques' under the direction of V.M. Moskolenko (Moscow). The system provides information about dangerous environmental occurrences such as tornados and hurricanes, making the forecast of extreme situations possible, especially in the areas of dangerous industries and objects. The created automatic system can be useful in solving the tasks relating to nuclear test monitoring. (author)

  6. The human discharge chain

    Science.gov (United States)

    Dudley, Scott C.; Heerema, Bret D.; Haaland, Ryan K.

    1997-06-01

    The common classroom demonstration of a human chain, charged by a Van de Graaff generator, and then discharged via the person at the end of the chain touching ground, is analyzed as a capacitor and resistor circuit model. The energy deposited in each person in the chain is determined. Further, the effect of increasing energy deposited in the person who touched ground, as the number of people in the chain is increased, is shown and quantified.

  7. THERMODYNAMIC MODEL OF THE CYCLE OF SPARK IGNITION ENGINE WITH EXHAUST GAS RECIRCULATION

    OpenAIRE

    Öğüçlü, Özer

    2015-01-01

    A thermodynamic model has been developed and applied to predict the emission levels and performance of a spark ignition engine with using Exhaust Gas Recirculation (EGR) gas. The model simulates the full thermodynamic cycle of the engine and includes heat transfer, combustion, gas exchange process, thermal dissociation of water and carbon dioxide, and chemical equilibrium. 

  8. Modeling And Simulation Of Combined Extrusion For Spark Plug Body Parts

    Science.gov (United States)

    Canta, T.; Noveanu, D.; Frunza, D.

    2004-06-01

    The paper presents the modeling and simulation for the extrusion technology of a new type of spark plug body for Dacia Supernova car. This technology was simulated using the finite elements modeling and analysis SuperForm software, designed for the simulation of plastic deformation processes. There is also presented a comparison between the results of the simulation and the industrial results.

  9. Commissioning of an automated microphotometer used in spark-source mass spectrometry

    International Nuclear Information System (INIS)

    Pearton, D.C.G.; Heron, C.

    1983-01-01

    A description of the automated microphotometer and its operation is given, which includes measurement under computer control. Speed and precision tests indicate that the system is superior in every respect to that in which an analyst reads photoplates in spark-source mass spectrometry

  10. Fe-Zn intermetallic phases prepared by diffusion annealing and spark-plasma sintering

    Czech Academy of Sciences Publication Activity Database

    Pokorný, P.; Cinert, Jakub; Pala, Zdeněk

    2016-01-01

    Roč. 50, č. 2 (2016), s. 253-256 ISSN 1580-2949 R&D Projects: GA ČR GB14-36566G Institutional support: RVO:61389021 Keywords : Fe-Zn intermetallics * spark-plasma sintering * diffusion annealing * phase composition * hardness Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 0.436, year: 2016

  11. 46 CFR 35.30-35 - Spark producing devices-TB/ALL.

    Science.gov (United States)

    2010-10-01

    ..., power driven or manually operated spark producing devices shall not be used in bulk cargo tanks, fuel oil tanks, cargo pumprooms, or enclosed spaces immediately above or adjacent to bulk cargo tanks unless all the following conditions are met: (1) The compartment itself is gas-free; (2) The compartments...

  12. Spark plasma-sintered Sn-based intermetallic alloys and their Li-storage studies

    CSIR Research Space (South Africa)

    Nithyadharseni, P

    2016-06-01

    Full Text Available In the present study, SnSb, SnSb/Fe, SnSb/Co, and SnSb/Ni alloy powders processed by co-precipitation were subjected to spark plasma-sintering (SPS) at 400 °C for 5 min. The compacts were structurally and morphologically characterized by X...

  13. A cinema for the unborn: moving pictures, mental pictures and Electra Sparks's New Thought film theory.

    Science.gov (United States)

    Ellis, Patrick

    2017-09-01

    In the 1910s, New York suffragette Electra Sparks wrote a series of essays in the Moving Picture News that advocated for cine-therapy treatments for pregnant women. Film was, in her view, the great democratizer of beautiful images, providing high-cultural access to the city's poor. These positive 'mental pictures' were important for her because, she claimed, in order to produce an attractive, healthy child, the mother must be exposed to quality cultural material. Sparks's championing of cinema during its 'second birth' was founded upon the premise of New Thought. This metaphysical Christian doctrine existed alongside the self-help and esoteric publishing domains and testified, above all, to the possibility of the 'mind-cure' of the body through the positive application of 'mental pictures'. Physiologically, their method began best in the womb, where the thoughts of the mother were of utmost importance: the eventual difference between birthing an Elephant Man or an Adonis. This positive maternal impression was commonplace in New Thought literature; it was Sparks's innovation to apply it to cinema. Investigating Sparks's film theory, practice and programming reveals her to be a harbinger of the abiding analogy between mind and motion picture that occupies film theorists to this day.

  14. Improving the Tribological Properties of Spark-Anodized Titanium by Magnetron Sputtered Diamond-Like Carbon

    Directory of Open Access Journals (Sweden)

    Zhaoxiang Chen

    2018-02-01

    Full Text Available Spark-anodization of titanium can produce adherent and wear-resistant TiO2 film on the surface, but the spark-anodized titanium has lots of surface micro-pores, resulting in an unstable and high friction coefficient against many counterparts. In this study, the diamond-like carbon (DLC was introduced into the micro-pores of spark-anodized titanium by the magnetron sputtering technique and a TiO2/DLC composite coating was fabricated. The microstructure and tribological properties of TiO2/DLC composite coating were investigated and compared with the anodic TiO2 mono-film and DLC mono-film. Results show that the DLC deposition significantly decreased the surface roughness and porosity of spark-anodized titanium. The fabricated TiO2/DLC composite coating exhibited a more stable and much lower friction coefficient than anodic TiO2 mono-film. Although the friction coefficient of the composite coating and the DLC mono-film was similar under both light load and heavy load conditions, the wear life of the composite coating was about 43% longer than that of DLC mono-film under heavy load condition. The wear rate of titanium with protective composite coating was much lower than that of titanium with DLC mono-film. The superior low friction coefficient and wear rate of the TiO2/DLC composite coating make it a good candidate as protective coating on titanium alloys.

  15. InnerSpark: A Creative Summer School and Artistic Community for Teenagers with Visual Arts Talent

    Science.gov (United States)

    Chin, Christina S.; Harrington, David M.

    2009-01-01

    InnerSpark is a residential summer arts training program for high school students established by the California State Legislature (California Education Code sections 8950-8957) in order to make it possible for "artistically gifted and talented students, broadly representative of the socioeconomic and ethnic diversity of the state, to receive…

  16. Influence of spark plasma sintering and baghdadite powder on mechanical properties of hydroxyapatite

    NARCIS (Netherlands)

    Khandan, A.; Karamian, E.; Mehdikhani-Nahrkhalaji, M.; Mirmohammadi, H.; Farzadi, A.; Ozada, N.; Heidarshenas, B.; Zamani, K.

    2015-01-01

    Since hydroxyapatite-based materials have similar composition and crystallinity as natural calcified tissues, can be used for bone/tissue engineering. In the present study a novel nanocomposite based on bioceramics such as Natural Hydroxyapatite (NHA) and Baghdadite (BAG), was sintered by spark

  17. Spark Plasma Sintered AlN-BN Composites and Its Thermal Conductivity

    NARCIS (Netherlands)

    Zhao Haiyang, [No Value; Wang Weimin, [No Value; Wang Hao, [No Value; Fu Zhengyi, [No Value

    2008-01-01

    A series of samples of hexagonal boron nitride-aluminum nitride ceramic composites with different amounts of CaF(2) as sintering aid were prepared by spark plasma sintered at 1700-1850 degrees C for 5 min. The addition of CaF(2) effectively lowered the sintering temperature and promoted the

  18. 78 FR 50412 - California State Nonroad Engine Pollution Control Standards; Amendments to Spark Ignition Marine...

    Science.gov (United States)

    2013-08-19

    ... Engine Pollution Control Standards; Amendments to Spark Ignition Marine Engine and Boat Regulations... Marine Engine and Boat Regulations (2008 Marine SI Amendments or 2008 Amendments). CARB requested EPA... outboard and personal watercraft engines and to enforce the first tier of regulations affecting inboard and...

  19. SPARK-UP; Seaweed Production And Refining of Kelp, Ulva and Palmaria

    NARCIS (Netherlands)

    Wald, J.; Visser, de W.; Brandenburg, W.A.; Jongschaap, R.E.E.; Werf, van der A.K.; Deelman, Berth-Jan; Helmendach-Nieuwenhuize, Carola

    2016-01-01

    In het SPARK-UP project, waarin de partners Arkema, PRI-WUR en North Seaweed samenwerkten aan de ontwikkeling van toepassing van zeewier in de biobased economy, is de afgelopen jaren veel werk verzet. In een bassin op het terrein van Arkema, heeft PRI een teeltsysteem opgezet en in gebruik genomen,

  20. Fabrication, spark plasma consolidation, and thermoelectric evaluation of nanostructured CoSb3

    DEFF Research Database (Denmark)

    Khan, A.; Saleemi, M.; Johnsson, M.

    2014-01-01

    to maintain pre-consolidation particle size and to compensate Sb evaporation during reduction. Significant changes in particle size and morphology were observed, and the post-reduction cooling was found to be an important stage in the process. The spark plasma sintering (SPS) parameters were optimized...

  1. Vaginal itching and discharge - child

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003159.htm Vaginal itching and discharge - child To use the sharing features on this ... problem in girls before the age of puberty. Vaginal discharge may also be present. The color, smell, and ...

  2. Spleen removal - open - adults - discharge

    Science.gov (United States)

    ... discharge; Spleen removal - adult - discharge References Poulose BK, Holzman MD. The spleen. In: Townsend CM, Beauchamp RD, ... provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial ...

  3. Plasma Discharge Process in a Pulsed Diaphragm Discharge System

    Science.gov (United States)

    Duan, Jianjin; Hu, Jue; Zhang, Chao; Wen, Yuanbin; Meng, Yuedong; Zhang, Chengxu

    2014-12-01

    As one of the most important steps in wastewater treatment, limited study on plasma discharge process is a key challenge in the development of plasma applications. In this study, we focus on the plasma discharge process of a pulsed diaphragm discharge system. According to the analysis, the pulsed diaphragm discharge proceeds in seven stages: (1) Joule heating and heat exchange stage; (2) nucleated site formation; (3) plasma generation (initiation of the breakdown stage); (4) avalanche growth and plasma expansion; (5) plasma contraction; (6) termination of the plasma discharge; and (7) heat exchange stage. From this analysis, a critical voltage criterion for breakdown is obtained. We anticipate this finding will provide guidance for a better application of plasma discharges, especially diaphragm plasma discharges.

  4. Effect of spark plug and fuel injector location on mixture stratification in a GDI engine - A CFD analysis

    Science.gov (United States)

    Saw, O. P.; Mallikarjuna, J. M.

    2017-09-01

    The mixture preparation in gasoline direct injection (GDI) engines operating at stratified condition plays an important role in deciding the combustion, performance and emission characteristics of the engine. In a wall-guided GDI engine, with a late fuel injection strategy, piston top surface is designed in such a way that the injected fuel is directed towards the spark plug to form a combustible mixture at the time of ignition. In addition, in these engines, location of spark-plug and fuel injector, fuel injection pressure and timing are also important to create a combustible mixture near the spark plug. Therefore, understanding the mixture formation under the influence of the location of spark plug and fuel injector is very essential for the optimization of the engine parameters. In this study, an attempt is made to understand the effect of spark plug and fuel injector location on the mixture preparation in a four-stroke, four-valve and wall-guided GDI engine operating under a stratified condition by using computational fluid dynamics (CFD) analysis. All the CFD simulations are carried out at an engine speed of 2000 rev/min., and compression ratio of 10.6, at an overall equivalence ratio (ER) of about 0.65. The fuel injection and spark timings are maintained at 605 and 710 CADs respectively. Finally, it is concluded that, combination of central spark plug and side fuel injector results in better combustion and performance.

  5. Compact Intracloud Discharges

    Energy Technology Data Exchange (ETDEWEB)

    Smith, David A. [Univ. of Colorado, Boulder, CO (United States)

    1998-11-01

    In November of 1993, mysterious signals recorded by a satellite-borne broadband VHF radio science experiment called Blackboard led to a completely unexpected discovery. Prior to launch of the ALEXIS satellite, it was thought that its secondary payload, Blackboard, would most often detect the radio emissions from lightning when its receiver was not overwhelmed by noise from narrowband communication carriers. Instead, the vast majority of events that triggered the instrument were isolated pairs of pulses that were one hundred times more energetic than normal thunderstorm electrical emissions. The events, which came to be known as TIPPs (for transionospheric pulse pairs), presented a true mystery to the geophysics community. At the time, it was not even known whether the events had natural or anthropogenic origins. After two and one half years of research into the unique signals, two ground-based receiver arrays in New Mexico first began to detect and record thunderstorm radio emissions that were consistent with the Blackboard observations. On two occasions, the ground-based systems and Blackboard even recorded emissions that were produced by the same exact events. From the ground based observations, it has been determined that TIPP events areproduced by brief, singular, isolated, intracloud electrical discharges that occur in intense regions of thunderstorms. These discharges have been dubbed CIDS, an acronym for compact intracloud discharges. During the summer of 1996, ground-based receiver arrays were used to record the electric field change signals and broadband HF emissions from hundreds of CIDS. Event timing that was accurate to within a few microseconds made possible the determination of source locations using methods of differential time of arrival. Ionospheric reflections of signals were recorded in addition to groundwave/line-of-sight signals and were used to determine accurate altitudes for the discharges. Twenty-four CIDS were recorded from three

  6. Continuous pile discharging machine

    International Nuclear Information System (INIS)

    Smith, P.P.

    1976-01-01

    A device for discharging cartridges from tubes under fluid pressure includes a cylindrical housing adapted to be seated in a leak-tight manner on the end of one of the tubes, a chute depending from the cylindrical housing near the end seated on the end of the tube, a rotatable piston having a wrench on the forward end thereof disposed in the cylindrical housing and adapted to manipulate a plug in the end of the tube, and a telescopic hydraulic ram adapted to move the piston toward the plug. In addition the wrench contains a magnet which prevents inadvertent uncoupling of the wrench and the plug. 7 claims, 10 drawing figures

  7. Continuous pile discharging machine

    Science.gov (United States)

    Smith, Phillips P.

    1976-05-11

    A device for discharging cartridges from tubes under fluid pressure includes a cylindrical housing adapted to be seated in a leak-tight manner on the end of one of the tubes, a chute depending from the cylindrical housing near the end seated on the end of the tube, a rotatable piston having a wrench on the forward end thereof disposed in the cylindrical housing and adapted to manipulate a plug in the end of the tube, and a telescopic hydraulic ram adapted to move the piston toward the plug. In addition the wrench contains a magnet which prevents inadvertent uncoupling of the wrench and the plug.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  9. Cálculo del exponente de Hurst utilizando Spark Streaming: enfoque experimental sobre un flujo de transacciones de criptomonedas

    OpenAIRE

    Basgall, María José; Hasperué, Waldo; Naiouf, Marcelo; Bariviera, Aurelio F.

    2017-01-01

    Actualmente es cada vez más común encontrarse con problemas de Big Data, donde las aplicaciones desarrolladas para resolver dichos problemas son implementadas en frameworks específicos. Uno de los que más se utiliza es Apache Spark, que posee el módulo Spark Streaming el cual permite el tratamiento de datos provenientes de un flujo de información potencialmente infinito. En este trabajo se presenta una aplicación implementada en Spark Streaming que realiza el cálculo del exponente de Hurst, u...

  10. CH4/NH3/H2O spark tholin: chemical analysis and interaction with Jovian aqueous clouds.

    Science.gov (United States)

    McDonald, G D; Khare, B N; Thompson, W R; Sagan, C

    1991-01-01

    The organic solid (tholin) produced by spark discharge in a CH4 + NH3 + H2O atmosphere is investigated, along with the separable components of its water-soluble fraction. The chemistry of this material serves as a provisional model for the interaction of Jovian organic heteropolymers with the deep aqueous clouds of Jupiter. Intact (unhydrolyzed) tholin is resolved into four chemically distinct fractions by high-pressure liquid chromatography (HPLC). Gel filtration chromatography reveals abundant components at molecular weights approximately or equal to 600-700 and 200-300 Da. Gas chromatography/mass spectrometry of derivatized hydrolysis products of unfractionated tholin shows about 10% by mass protein and nonprotein amino acids, chiefly glycine, alanine, aspartic acid, beta-alanine, and beta-aminobutyric acid, and 12% by mass other organic acids and hydroxy acids. The stereospecificity of alanine is investigated and shown to be racemic. The four principal HPLC fractions yield distinctly different proportions of amino acids. Chemical tests show that small peptides or organic molecules containing multiple amino acid precursors are a possibility in the intact tholins, but substantial quantities of large peptides are not indicated. Candidate 700-Da molecules have a central unsaturated, hydrocarbon- and nitrile-rich core, linked by acid-labile (ester or amide) bonds to amino acid and carboxylic acid side groups. The core is probably not HCN "polymer." The concentration of amino acids from tholin hydrolysis in the lower aqueous clouds of Jupiter, about 0.1 micromole, is enough to maintain small populations of terrestrial microorganisms even if the amino acids must serve as the sole carbon source.

  11. SciSpark: Highly Interactive and Scalable Model Evaluation and Climate Metrics

    Science.gov (United States)

    Wilson, B. D.; Palamuttam, R. S.; Mogrovejo, R. M.; Whitehall, K. D.; Mattmann, C. A.; Verma, R.; Waliser, D. E.; Lee, H.

    2015-12-01

    Remote sensing data and climate model output are multi-dimensional arrays of massive sizes locked away in heterogeneous file formats (HDF5/4, NetCDF 3/4) and metadata models (HDF-EOS, CF) making it difficult to perform multi-stage, iterative science processing since each stage requires writing and reading data to and from disk. We are developing a lightning fast Big Data technology called SciSpark based on ApacheTM Spark under a NASA AIST grant (PI Mattmann). Spark implements the map-reduce paradigm for parallel computing on a cluster, but emphasizes in-memory computation, "spilling" to disk only as needed, and so outperforms the disk-based ApacheTM Hadoop by 100x in memory and by 10x on disk. SciSpark will enable scalable model evaluation by executing large-scale comparisons of A-Train satellite observations to model grids on a cluster of 10 to 1000 compute nodes. This 2nd generation capability for NASA's Regional Climate Model Evaluation System (RCMES) will compute simple climate metrics at interactive speeds, and extend to quite sophisticated iterative algorithms such as machine-learning based clustering of temperature PDFs, and even graph-based algorithms for searching for Mesocale Convective Complexes. We have implemented a parallel data ingest capability in which the user specifies desired variables (arrays) as several time-sorted lists of URL's (i.e. using OPeNDAP model.nc?varname, or local files). The specified variables are partitioned by time/space and then each Spark node pulls its bundle of arrays into memory to begin a computation pipeline. We also investigated the performance of several N-dim. array libraries (scala breeze, java jblas & netlib-java, and ND4J). We are currently developing science codes using ND4J and studying memory behavior on the JVM. On the pyspark side, many of our science codes already use the numpy and SciPy ecosystems. The talk will cover: the architecture of SciSpark, the design of the scientific RDD (sRDD) data structure, our

  12. Pulsed Power Issues for the Phillips Laboratory's Capillary Discharge Soft X-Ray Laser Experiment.

    Science.gov (United States)

    Ruden, Edward L.; Graham, Jack D.

    1996-11-01

    The Phillips Laboratory is presently attempting to reproduce the high gain laser results of J. Rocca's Capillary Discharge z-pinch pumped 46.9 nm Ne-like Ar laser. This poster discusses the design and operation of the PL laser's pulsed power circuit. The capillary circuit consists of a low inductance 3nH water capacitor discharged by a coaxial spark gap into a presently 12 cm capillary. The capillary is supplied with 39 kA of current which rises in 20ns. The capillary tube itself is submerged in the same water supply as the capacitor. The effect of the slower speed of electromagnetic propagation in water vs. plastic on the dynamic inductance of the plastic capillary is discussed. Higher current rise rates for the first few ns apparently result from the lag in the EM propagation in the water. This effect may improve implosion uniformity during the initial formative phase of the imploding z- pinch plasma.

  13. Analysis of Multipactor Discharge

    International Nuclear Information System (INIS)

    Lau, Y. Y.

    2005-01-01

    Several comprehensive studies of radio frequency (rf) breakdown and rf heating are reported. They are of general interest to magnetic confinement fusion, rf linac, and high power microwave source development. The major results include: (1) a ground-breaking theory of multipactor discharge on dielectric, including a successful proof-of-principle experiment that verified the newly developed scaling laws, (2) an in depth investigation of the failure mechanisms of diamond windows and ceramic windows, and of the roles of graphitization, thin films of coating and contaminants, and (3) a most comprehensive theory, to date, on the heating of particulates by an electromagnetic pulse, and on the roles of rf magnetic field heating and of rf electric field heating, including the construction of new scaling laws that govern them. The above form a valuable knowledge base for the general problem of heating phenomenology

  14. Magnetic microstructure and magnetic properties of spark plasma sintered NdFeB magnets

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Y.L., E-mail: hyl1019_lin@163.com [School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Wang, Y.; Hou, Y.H.; Wang, Y.L.; Wu, Y.; Ma, S.C. [School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Liu, Z.W.; Zeng, D.C. [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Tian, Y.; Xia, W.X. [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Zhong, Z.C., E-mail: zzhong2014@sina.com [School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063 (China)

    2016-02-01

    Nanocrystalline NdFeB magnets were prepared by spark plasma sintering (SPS) technique using melt-spun ribbons as starting materials. A distinct two-zone structure with coarse grain zone and fine grain zone was formed in the SPSed magnets. Multi-domain particle in coarse grain zone and exchange interaction domain for fine grain zone were observed. Intergranular non-magnetic phase was favorable to improve the coercivity due to the enhancement of domain wall pinning effects and increased exchange-decouple. The remanent polarization of 0.83 T, coercivity of 1516 kA/m, and maximum energy product of 118 kJ/m{sup 3} are obtained for an isotropic magnet. - Highlights: • Nanocrystalline NdFeB magnets were prepared by spark plasma sintering technique. • Multi-domain particle and exchange interaction domain were observed. • Magnetic microstructure and their relation to the properties were investigated.

  15. Prediction of heart disease using apache spark analysing decision trees and gradient boosting algorithm

    Science.gov (United States)

    Chugh, Saryu; Arivu Selvan, K.; Nadesh, RK

    2017-11-01

    Numerous destructive things influence the working arrangement of human body as hypertension, smoking, obesity, inappropriate medication taking which causes many contrasting diseases as diabetes, thyroid, strokes and coronary diseases. The impermanence and horribleness of the environment situation is also the reason for the coronary disease. The structure of Apache start relies on the evolution which requires gathering of the data. To break down the significance of use programming focused on data structure the Apache stop ought to be utilized and it gives various central focuses as it is fast in light as it uses memory worked in preparing. Apache Spark continues running on dispersed environment and chops down the data in bunches giving a high profitability rate. Utilizing mining procedure as a part of the determination of coronary disease has been exhaustively examined indicating worthy levels of precision. Decision trees, Neural Network, Gradient Boosting Algorithm are the various apache spark proficiencies which help in collecting the information.

  16. Influence of the voltage-time derivative in X-ray emission from laboratory sparks

    Science.gov (United States)

    March, Víctor; Montanyà, Joan

    2010-10-01

    X-rays produced by laboratory sparks in air at atmospheric pressure for rod-rod and rod-plane configurations were observed. A total of 510 sparks were applied for both polarities. The paper shows the effects of the voltage rise time and the peak voltage in the generation of X-rays. It is found here that shorter rise times and high peak voltages tend to produce more X-rays emissions with higher energies than longer front waveforms or lower peak voltages. In a similar way, higher voltage variations produce more energetic emissions. This finding suggests that the variation of the electric field before the breakdown can play a fundamental role in the X-ray production. The results are similar with the observations of X-rays produced in natural lightning where detections have been associated to leader steps before the return stroke.

  17. A Feature Selection Method for Large-Scale Network Traffic Classification Based on Spark

    Directory of Open Access Journals (Sweden)

    Yong Wang

    2016-02-01

    Full Text Available Currently, with the rapid increasing of data scales in network traffic classifications, how to select traffic features efficiently is becoming a big challenge. Although a number of traditional feature selection methods using the Hadoop-MapReduce framework have been proposed, the execution time was still unsatisfactory with numeral iterative computations during the processing. To address this issue, an efficient feature selection method for network traffic based on a new parallel computing framework called Spark is proposed in this paper. In our approach, the complete feature set is firstly preprocessed based on Fisher score, and a sequential forward search strategy is employed for subsets. The optimal feature subset is then selected using the continuous iterations of the Spark computing framework. The implementation demonstrates that, on the precondition of keeping the classification accuracy, our method reduces the time cost of modeling and classification, and improves the execution efficiency of feature selection significantly.

  18. Synthesis and characterization of aluminium–alumina micro- and nano-composites by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Dash, K., E-mail: khushbudash@gmail.com; Chaira, D.; Ray, B.C.

    2013-07-15

    Graphical abstract: The evolution of microstructure by varying the particle size of reinforcement in the matrix employing spark plasma sintering has been demonstrated here in Al–Al{sub 2}O{sub 3} system. An emphasis has been laid on varying the reinforcement particle size and evaluating the microstructural morphologies and their implications on mechanical performance of the composites. Nanocomposites of 0.5, 1, 3, 5, 7 volume % alumina (average size < 50 nm) reinforced in aluminium matrix were fabricated by powder metallurgy route using spark plasma sintering technique technique at a temperature of 773 K and pressure of 50 MPa. Another set of specimens having composition 1, 5, 20 vol.% of alumina (average size ∼ 10 μm) had been fabricated to compare the physical as well as mechanical attributes of the microcomposite as well as the nanocomposites. These micro- and nano-composites have been characterized using X-ray diffraction, scanning electron microscopy and transmission electron microscopy followed by density, microhardness and nanoindentation measurements. The alumina nanoparticles revealed an interface showing appreciable physical intimacy with the aluminium matrix compared to that of the alumina microparticles. The interfacial integrity in case of nanocomposites is better than in the microcomposite which has been studied using microscopic techniques. Spark plasma sintering imparts enhanced densification as well as matrix-reinforcement proximity which has been corroborated with the experimental results. - Highlights: • The Al–Al{sub 2}O{sub 3} micro- and nano-composites fabricated by spark plasma sintering. • Better matrix-reinforcement integrity in nanocomposites than microcomposites. • Spark plasma sintering method results in higher density and hardness values. • High density and hardness values of nanocomposites than microcomposites. • High dislocation density in spark plasma sintered Al–Al{sub 2}O{sub 3} composites. - Abstract: In the

  19. A jumping spark counter for various applications; rapid determination of its counting parameters

    International Nuclear Information System (INIS)

    Varnagy, M.; Vasvary, L.; Gyarmati, E.; Juhasz, S.; Scharbert, T.; Sztaricskai, T.

    1977-01-01

    On the basis of the method proposed by Cross and Tommasino a jumping spark counter (JSC) has been constructed which is applicable for the counting (continuously or 'step by step') of the perforations in thin (5-20μm) polymer foils. The JSC was combined with a DIDAC 4000 multichannel pulse-height analyser and multiscaler to determine automatically the best parameters and procedures for spark counting as well as to study the working mechanism of the JSC. Investigations were performed on etched Markrofol GK foils irradiated with fission fragments and exposed to 0.35 MRad gamma-rays. The track density interval studies was 0-50000 tracks/cm 2 . The possibility of the adoption of JSC for neutron dosimetric application, evaluation of angular distribution and for safegaurd purposes was tested. The possible consequences of the results are discussed. (Auth.)

  20. A Parallel Approach for Frequent Subgraph Mining in a Single Large Graph Using Spark

    Directory of Open Access Journals (Sweden)

    Fengcai Qiao

    2018-02-01

    Full Text Available Frequent subgraph mining (FSM plays an important role in graph mining, attracting a great deal of attention in many areas, such as bioinformatics, web data mining and social networks. In this paper, we propose SSiGraM (Spark based Single Graph Mining, a Spark based parallel frequent subgraph mining algorithm in a single large graph. Aiming to approach the two computational challenges of FSM, we conduct the subgraph extension and support evaluation parallel across all the distributed cluster worker nodes. In addition, we also employ a heuristic search strategy and three novel optimizations: load balancing, pre-search pruning and top-down pruning in the support evaluation process, which significantly improve the performance. Extensive experiments with four different real-world datasets demonstrate that the proposed algorithm outperforms the existing GraMi (Graph Mining algorithm by an order of magnitude for all datasets and can work with a lower support threshold.

  1. Simulation of Aldehyde Emissions from an Ethanol Fueled Spark Ignition Engine and Comparison with FTIR Measurements

    International Nuclear Information System (INIS)

    Zaránte, Paola Helena Barros; Sodre, Jose Ricardo

    2016-01-01

    This paper presents a mathematical model that calculates aldehyde emissions in the exhaust of a spark ignition engine fueled with ethanol. The numerical model for aldehyde emissions was developed using FORTRAN software, with the input data obtained from a dedicated engine cycle simulation software, AVL BOOST. The model calculates formaldehyde and acetaldehyde emissions, formed from the partial oxidation of methane, ethane and unburned ethanol. The calculated values were compared with experimental data obtained by Fourier Transform Infrared Spectroscopy (FTIR). The experiments were performed with a mid-size sedan powered by a 1.4-liter spark ignition engine on a chassis dynamometer. In general, the results demonstrate that the concentrations of aldehydes and the source elements increased with engine speed and exhaust gas temperature. A reasonable agreement between simulated and measured values was achieved. (paper)

  2. Evaluating the Impact of Data Placement to Spark and SciDB with an Earth Science Use Case

    Science.gov (United States)

    Doan, Khoa; Oloso, Amidu; Kuo, Kwo-Sen; Clune, Thomas; Yu, Hongfeng; Nelson, Brian; Zhang, Jian

    2016-01-01

    We investigate the impact of data placement for two Big Data technologies, Spark and SciDB, with a use case from Earth Science where data arrays are multidimensional. Simultaneously, this investigation provides an opportunity to evaluate the performance of the technologies involved. Two datastores, HDFS and Cassandra, are used with Spark for our comparison. It is found that Spark with Cassandra performs better than with HDFS, but SciDB performs better yet than Spark with either datastore. The investigation also underscores the value of having data aligned for the most common analysis scenarios in advance on a shared nothing architecture. Otherwise, repartitioning needs to be carried out on the fly, degrading overall performance.

  3. Heart bypass surgery - minimally invasive - discharge

    Science.gov (United States)

    ... invasive direct coronary artery bypass - discharge; MIDCAB - discharge; Robot assisted coronary artery bypass - discharge; RACAB - discharge; Keyhole ... M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health ...

  4. X-ray emissions from centimeter-long streamer corona discharges

    Science.gov (United States)

    da Silva, C. L.; Millan, R. M.; McGaw, D. G.; Yu, C. T.; Putter, A. S.; Labelle, J. W.; Dwyer, J. R.

    2017-12-01

    In this work we provide extensive evidence that runaway electron acceleration and subsequent bremsstrahlung X-ray emission are a common feature in electrical discharges of negative polarity. They can be easily detected at voltages as low as 100 kV, indicating that all negative lightning could potentially produce runaway electrons. We show that centimeter-long streamer corona discharges produce bursts of X-ray radiation that are emitted by a source that is highly compact in space and time. Therefore, the emitted X-ray photons arrive together at the detector and pile up. Median burst energies vary between 33-96% of the total 100 keV available electrostatic energy that an electron can acquire in the gap. We present detailed statistical analysis of 5000+ discharges, showing that X-rays are observed in as many as 60% of the triggers, depending on the configuration. X-ray detection is more frequent when: the streamer corona discharge is not followed by a spark, the detector is oriented perpendicular to the gap, and a thicker anode is used. We show that for an 8-cm-long gap, X-rays are produced when runaway electrons hit the anode, and that the runaway electron acceleration is not correlated with streamer collisions, as inferred in meter-long discharges. The described experiment is a promising way for measuring the runaway electron distribution very close to the source and its dependence on the applied voltage.

  5. Synergistic effect of pulsed corona discharges and ozonation on decolourization of methylene blue in water

    CERN Document Server

    Malik, M A; Ghaffar, A; Ahmed, K

    2002-01-01

    The effect of O sub 2 and O sub 3 bubbling on decolourization of methylene blue by pulsed corona discharges in water was studied. The pulsed corona discharges were produced by charging an 80 pF capacitor with a 40 kV DC source, through a 100 M OMEGA resistor, and discharging it into a needle-plate type reactor at 60 Hz through a rotating spark gap switch. A 20 ml sample of 13.25 mg l sup - sup 1 methylene blue in distilled water was decolourized in 120 min. Bubbling O sub 2 at 10 ml min sup - sup 1 through the discharge region reduced the decolourization time to 25 min. Bubbling O sub 2 containing 1500 mu mol O sub 3 l sup - sup 1 at 10 ml min sup - sup 1 reduced the decolourization time to 8 min. The O sub 3 was produced by fractionating input energy between a water treatment reactor and a O sub 3 generator, i.e. no additional energy was consumed for O sub 3 production. Under the same experimental conditions methylene blue solution in tap water was decolourized in >210 min by corona discharge in solution, in...

  6. Exploring the Effect of Sample Properties on Spark-Induced Breakdown Spectroscopy

    OpenAIRE

    Marino, Michael J; Dieffenbach, Payson; Krause, Liesl A; Diwakar, Prasoon; Hassanein, Ahmed

    2015-01-01

    Optical emission spectroscopy techniques such as laser-induced breakdown spectroscopy (LIBS) and spark-induced breakdown spectroscopy (SIBS) provide portable and robust methods for elemental detection in real-time. Laser-produced emissions are then used for quantitative and qualitative analysis of a sample material with applications in explosives detection. For both techniques, the main obstacles have always been signal intensity, accuracy, and sensitivity of detection. The main advantage of ...

  7. Application of Alcohols to Dual - Fuel Feeding the Spark-Ignition and Self-Ignition Engines

    OpenAIRE

    Stelmasiak Zdzisław

    2014-01-01

    This paper concerns analysis of possible use of alcohols for the feeding of self - ignition and spark-ignition engines operating in a dual- fuel mode, i.e. simultaneously combusting alcohol and diesel oil or alcohol and petrol. Issues associated with the requirements for application of bio-fuels were presented with taking into account National Index Targets, bio-ethanol production methods and dynamics of its production worldwide and in Poland. Te considerations are illustrated by results of t...

  8. Sparking ideas, making connections:Digital Film Archives and collaborative scholarship

    OpenAIRE

    Atkinson, Sarah Anne

    2012-01-01

    Film archiving is a rapidly changing field as a result of the accelerating development of online digital technologies. Taking as its case study the example of SP-ARK (1), the Sally Potter online film archive, this article proposes a notable shift from the traditional single-user archive model to emerging multi-user, collaborative forms of archival scholarship. The digital preservation and presentation of archival materials dramatically impact upon the nature of the types and levels of access ...

  9. Master Sintering Surface: A practical approach to its construction and utilization for Spark Plasma Sintering prediction

    Directory of Open Access Journals (Sweden)

    Pouchly V.

    2012-01-01

    Full Text Available The sintering is a complex thermally activated process, thus any prediction of sintering behaviour is very welcome not only for industrial purposes. Presented paper shows the possibility of densification prediction based on concept of Master Sintering Surface (MSS for pressure assisted Spark Plasma Sintering (SPS. User friendly software for evaluation of the MSS is presented. The concept was used for densification prediction of alumina ceramics sintered by SPS.

  10. Effect of gasket of varying thickness on spark ignition engines | Ajayi ...

    African Journals Online (AJOL)

    In the study of Toyota, In-line, 4 cylinders, spark ignition engine using gaskets of varying thicknesses (1.75mm, 3.5mm, 5.25mm, 7mm and 8.75mm) between the cylinder head and the engine block, the performance characteristics of the engine was investigated via the effect of engine speed on brake power, brake thermal ...

  11. Nanocrystalline Al7075+1 wt % Zr Alloy Prepared Using Mechanical Milling and Spark Plasma Sintering.

    Czech Academy of Sciences Publication Activity Database

    Molnárová, O.; Málek, P.; Veselý, J.; Šlapáková, M.; Minárik, P.; Lukáč, František; Chráska, Tomáš; Novák, P.; Průša, F.

    2017-01-01

    Roč. 10, č. 9 (2017), č. článku 1105. ISSN 1996-1944 R&D Projects: GA ČR(CZ) GA15-15609S Institutional support: RVO:61389021 Keywords : gas atomization * mechanical milling * spark plasma sintering * microstructure * microhardness * recrystallization Subject RIV: JG - Metallurgy OBOR OECD: Materials engineering Impact factor: 2.654, year: 2016 http://www.readcube.com/articles/10.3390/ma10091105

  12. Spark Plasma Sintering of a Gas Atomized Al7075 Alloy: Microstructure and Properties

    Czech Academy of Sciences Publication Activity Database

    Molnárová, O.; Málek, P.; Lukáč, František; Chráska, Tomáš

    2016-01-01

    Roč. 9, č. 12 (2016), č. článku 1004. ISSN 1996-1944 R&D Projects: GA ČR(CZ) GA15-15609S Institutional support: RVO:61389021 Keywords : gas atomized Al7075 alloy * spark plasma sintering * microstructure * microhardness * high temperature stability Subject RIV: JJ - Other Materials Impact factor: 2.654, year: 2016 http://www.mdpi.com/1996-1944/9/12/1004

  13. Method for operating a spark-ignition, direct-injection internal combustion engine

    Science.gov (United States)

    Narayanaswamy, Kushal; Koch, Calvin K.; Najt, Paul M.; Szekely, Jr., Gerald A.; Toner, Joel G.

    2015-06-02

    A spark-ignition, direct-injection internal combustion engine is coupled to an exhaust aftertreatment system including a three-way catalytic converter upstream of an NH3-SCR catalyst. A method for operating the engine includes operating the engine in a fuel cutoff mode and coincidentally executing a second fuel injection control scheme upon detecting an engine load that permits operation in the fuel cutoff mode.

  14. Cavitation Erosion of Electro Spark Deposited Nitinol vs. Stellite Alloy on Stainless Steel Substrate

    Science.gov (United States)

    2015-07-15

    Chromium Cu Copper ESD Electro Spark Deposition Fe Iron HB Brinnell Hardness in Inch kgf Kilogram-force ksi Kilo pounds per square inch, 1000 pound...1 Nickel and Nitinol Fused onto SS-304 The team at APAS theorized that Nitinol’s extreme hardness , along with high chromium levels in the...contaminate their microstructure with oxygen, vacancies, and other foreign substances. Welding also tends to deposit an uncontrolled and overly

  15. Over compression influence to the performances of the spark ignition engines

    Science.gov (United States)

    Rakosi, E.; Talif, S. G.; Manolache, G.

    2016-08-01

    This paper presents the theoretical and experimental results of some procedures used in improving the performances of the automobile spark ignition engines. The study uses direct injection and high over-compression applied to a standard engine. To this purpose, the paper contains both the constructive solutions and the results obtained from the test bed concerning the engine power indices, fuel consumption and exhaust emissions.

  16. About the constructive and functional particularities of spark ignition engines with gasoline direct injection: experimental results

    Science.gov (United States)

    Niculae, M.; Ivan, F.; Neacsu, D.

    2017-08-01

    The paper aims to analyze and compare the environmental performances between a gasoline direct engine and a multi-point injection engine. There are analyzed the stages of emission formation during the New European Driving Cycle. The paper points out the dynamic, economic and environmental performances of spark ignition engines equipped with a GDI systems. Reason why, we believe the widespread implementation of this technology is today an immediate need.

  17. Research of combustion in older generation spark-ignition engines in the condition of use leaded and unleaded petrol

    OpenAIRE

    Bulatović Željko M.; Rakić Slavko N.; Knežević Dragan M.; Tomić Miroljub V.; Bojer Ljubiša M.; Radić Dragoslav B.; Jerkin Goran L.

    2014-01-01

    This paper analyzes the potential problems in the exploitation of the older generation of spark-ignition engines with higher octane number of petrol (unleaded petrol BMB 95) than required (leaded petrol MB 86). Within the experimental tests on two different engines (STEYR-PUCH model 712 and GAZ 41) by applying piezoelectric pressure sensors integrated with the engine spark plugs, acceleration sensors (accelerometers) and special electronic block connected w...

  18. Consolidation of W–Ta composites: Hot isostatic pressing and spark and pulse plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Dias, M., E-mail: marta.dias@itn.pt [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Guerreiro, F. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Correia, J.B. [LNEG, Laboratório Nacional de Energia e Geologia, Estrada do Paço do Lumiar, 1649-038 Lisboa (Portugal); Galatanu, A. [National Institute of Materials Physics, Atomistilor 105 bis Bucharest-Magurele, 077125 Ilfov (Romania); Rosiński, M. [Warsaw University of Technology, Faculty of Materials Science and Engineering, Warsaw (Poland); Monge, M.A.; Munoz, A. [Departamento de Física, Univerdidad Carlos III de Madrid, Avd. de la Universidad 30, 28911 Madrid (Spain); Alves, E. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Carvalho, P.A. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); CeFEMA, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

    2015-10-15

    Highlights: • Consolidation of W–Ta composites using three techniques: HIP, SPS and PPS. • Comparison of consolidation methods in terms of W–Ta interdiffusion and densification. • Microstructure analysis in terms of oxides formation. - Abstract: Composites consisting of tantalum fiber/powder dispersed in a nanostructured W matrix have been consolidated by spark and pulse plasma sintering as well as by hot isostatic pressing. The microstructural observations revealed that the tungsten–tantalum fiber composites consolidated by hot isostatic pressing and pulse plasma sintering presented a continuous layer of Ta{sub 2}O{sub 5} phase at the W/Ta interfaces, while the samples consolidated by spark plasma sintering evidenced a Ta + Ta{sub 2}O{sub 5} eutectic mixture due to the higher temperature of this consolidation process. Similar results have been obtained for the tungsten–tantalum powder composites. A (W, Ta) solid solution was detected around the prior nanostructured W particles in tungsten–tantalum powder composites consolidated by spark and pulse plasma sintering. Higher densifications were obtained for composites consolidated by hot isostatic pressing and pulse plasma sintering.

  19. A multi-platform evaluation of the randomized CX low-rank matrix factorization in Spark

    Energy Technology Data Exchange (ETDEWEB)

    Gittens, Alex; Kottalam, Jey; Yang, Jiyan; Ringenburg, Michael, F.; Chhugani, Jatin; Racah, Evan; Singh, Mohitdeep; Yao, Yushu; Fischer, Curt; Ruebel, Oliver; Bowen, Benjamin; Lewis, Norman, G.; Mahoney, Michael, W.; Krishnamurthy, Venkat; Prabhat, Mr

    2017-07-27

    We investigate the performance and scalability of the randomized CX low-rank matrix factorization and demonstrate its applicability through the analysis of a 1TB mass spectrometry imaging (MSI) dataset, using Apache Spark on an Amazon EC2 cluster, a Cray XC40 system, and an experimental Cray cluster. We implemented this factorization both as a parallelized C implementation with hand-tuned optimizations and in Scala using the Apache Spark high-level cluster computing framework. We obtained consistent performance across the three platforms: using Spark we were able to process the 1TB size dataset in under 30 minutes with 960 cores on all systems, with the fastest times obtained on the experimental Cray cluster. In comparison, the C implementation was 21X faster on the Amazon EC2 system, due to careful cache optimizations, bandwidth-friendly access of matrices and vector computation using SIMD units. We report these results and their implications on the hardware and software issues arising in supporting data-centric workloads in parallel and distributed environments.

  20. Skip cycle system for spark ignition engines: An experimental investigation of a new type working strategy

    International Nuclear Information System (INIS)

    Kutlar, Osman Akin; Arslan, Hikmet; Calik, Alper T.

    2007-01-01

    A new type working strategy for spark ignition engine, named skip cycle, is examined. The main idea is to reduce the effective stroke volume of an engine by cutting off fuel injection and spark ignition in some of the classical four stroke cycles. When the cycle is skipped, additionally, a rotary valve is used in the intake to reduce pumping losses in part load conditions. The effect of this strategy is similar to that of variable displacement engines. Alternative power stroke fractions in one cycle and applicability in single cylinder engines are specific advantageous properties of the proposed system. A thermodynamic model, besides experimental results, is used to explain the skip cycle strategy in more detail. This theoretical investigation shows considerable potential to increase the efficiency at part load conditions. Experimental results obtained with this novel strategy show that the throttle valve of the engine opens wider and the minimum spark advance for maximum brake torque decreases in comparison to those of the classical operation system. The brake specific fuel consumption decreases at very low speed and load, while it increases at higher speed and load due to the increased fuel loss within the skipped cycles. In this working mode, the engine operates at lower idle speed without any stability problem; and moreover with less fuel consumption

  1. Formation and properties of two-phase bulk metallic glasses by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Xie Guoqiang, E-mail: xiegq@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Louzguine-Luzgin, D.V. [WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Inoue, Akihisa [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)

    2011-06-15

    Research highlights: > Two-phase bulk metallic glasses with high strength and good soft magnetic properties as well as satisfying large-size requirements were produced by spark plasma sintering. > Effects of sintering temperature on thermal stability, microstructure, mechanical and magnetic properties were investigated. > Densified samples were obtained by the spark plasma sintering at above 773 K. - Abstract: Using a mixture of the gas-atomized Ni{sub 52.5}Nb{sub 10}Zr{sub 15}Ti{sub 15}Pt{sub 7.5} and Fe{sub 73}Si{sub 7}B{sub 17}Nb{sub 3} glassy alloy powders, we produced the two-phase bulk metallic glass (BMG) with high strength and good soft magnetic properties as well as satisfying large-size requirements by the spark plasma sintering (SPS) process. Two kinds of glassy particulates were homogeneously dispersed each other. With an increase in sintering temperature, density of the produced samples increased, and densified samples were obtained by the SPS process at above 773 K. Good bonding state among the Ni- and Fe-based glassy particulates was achieved.

  2. Synthesis and characterization of copper–alumina metal matrix composite by conventional and spark plasma sintering

    International Nuclear Information System (INIS)

    Dash, K.; Ray, B.C.; Chaira, D.

    2012-01-01

    Graphical abstract: The evolution of microstructure, density and hardness of Cu–Al 2 O 3 metal matrix composites with different techniques of sintering has been demonstrated here. The effect of sintering atmosphere has also been discussed. Synthesis of microcomposites was carried out by reinforcing 5, 10 and 15 vol.% of alumina powder particle (average size ∼5.71 μm) in copper matrix via conventional sintering using H 2 and N 2 atmospheres. Nanocomposites of 1, 5, 7 vol.% alumina (average size 2 O 3 metal matrix microcomposites and nanocomposites via conventional route and spark plasma sintering routes are studied and compared. Maximum Vickers hardness of 60 and 80 are obtained when the Cu–15 vol.% Al 2 O 3 is conventionally sintered in N 2 and H 2 atmosphere respectively. However, maximum hardness value of 125 is achieved for the Cu–5 vol.% Al 2 O 3 nanocomposite prepared by spark plasma sintering. It has been observed that Cu–Al 2 O 3 metal matrix composite (MMC) shows poor mechanical properties when it is conventionally sintered in N 2 atmosphere than H 2 atmosphere. Highlights: ► Better matrix–reinforcement interfacial bonding and compatibility in hydrogen atmosphere than nitrogen atmosphere. ► An improvement in density and hardness under hydrogen atmosphere than in nitrogen atmosphere is manifested. ► Spark plasma sintering method results in higher density and hardness values than conventional sintering. - Abstract: The evolution of microstructure, density and hardness of Cu–Al 2 O 3 metal matrix composites with different techniques of sintering have been demonstrated here. The effect of sintering atmosphere on the interfacial compatibility of matrix and reinforcement has also been discussed. Synthesis of microcomposites was carried out by reinforcing 5, 10 and 15 vol.% of alumina powder particles (average size ∼5.71 μm) in copper matrix via conventional sintering using N 2, H 2 and Ar atmospheres. Nanocomposites of 1, 5, 7 vol

  3. The ASDEX Upgrade discharge schedule

    International Nuclear Information System (INIS)

    Neu, G.; Engelhardt, K.; Raupp, G.; Treutterer, W.; Zasche, D.; Zehetbauer, T.

    2007-01-01

    ASDEX Upgrade's recently commissioned discharge control system (DCS) marks the transition from a traditional programmed system to a highly flexible 'data driven' one. The allocation of application processes (APs) to controllers, the interconnection of APs through uniquely named signals, and AP control parameter values are all defined as data, and can easily be adapted to the requirements of a particular discharge. The data is laid down in a set of XML documents which APs request via HTTP from a configuration server before a discharge. The use of XML allows for easy parsing, and structural validation through (XSD) schemas. The central input to the configuration process is the discharge schedule (DS), which embodies the dynamic behaviour of a planned discharge as reference trajectories grouped in segments, concatenated through transition conditions. Editing, generation and validation tools, and version control through CVS allow for efficient management of DSs

  4. Discharge Planning in Chronic Conditions

    Science.gov (United States)

    McMartin, K

    2013-01-01

    Background Chronically ill people experience frequent changes in health status accompanied by multiple transitions between care settings and care providers. Discharge planning provides support services, follow-up activities, and other interventions that span pre-hospital discharge to post-hospital settings. Objective To determine if discharge planning is effective at reducing health resource utilization and improving patient outcomes compared with standard care alone. Data Sources A standard systematic literature search was conducted for studies published from January 1, 2004, until December 13, 2011. Review Methods Reports, randomized controlled trials, systematic reviews, and meta-analyses with 1 month or more of follow-up and limited to specified chronic conditions were examined. Outcomes included mortality/survival, readmissions and emergency department (ED) visits, hospital length of stay (LOS), health-related quality of life (HRQOL), and patient satisfaction. Results One meta-analysis compared individualized discharge planning to usual care and found a significant reduction in readmissions favouring individualized discharge planning. A second meta-analysis compared comprehensive discharge planning with postdischarge support to usual care. There was a significant reduction in readmissions favouring discharge planning with postdischarge support. However, there was significant statistical heterogeneity. For both meta-analyses there was a nonsignificant reduction in mortality between the study arms. Limitations There was difficulty in distinguishing the relative contribution of each element within the terms “discharge planning” and “postdischarge support.” For most studies, “usual care” was not explicitly described. Conclusions Compared with usual care, there was moderate quality evidence that individualized discharge planning is more effective at reducing readmissions or hospital LOS but not mortality, and very low quality evidence that it is more

  5. Recurrent vaginal discharge in children.

    Science.gov (United States)

    McGreal, Sharon; Wood, Paul

    2013-08-01

    Childhood vaginal discharge remains a frequent reason for referral from primary to secondary care. The Pediatric and Adolescent Gynecology (PAG) service at Kettering General Hospital was established in 1993 and provides a specialized service that meets the needs of children with gynaecological conditions. To investigate recurrent vaginal discharge noting symptomatology, defining pathogens, common and rarer causes, exploring management regimes, and any changes in practice over time. Retrospective review spanning 15 years identifying prepubertal children attending the outpatient PAG clinic with recurrent vaginal discharge. We reviewed the medical notes individually. 110 patients were identified; 85% were referred from primary care. The age distribution was bimodal at four and eight years. Thirty-five percent of our patients were discharged after the initial consultation. The commonest cause of discharge was vulvovaginitis (82%). Other important causes included suspected sexual abuse (5%), foreign body (3%), labial adhesions (3%), vaginal agenesis (2%). 35% of patients were admitted for vaginoscopy. Vaginal discharge is the most common gynecological symptom in prepubertal girls and can cause repeated clinical episodes. Vulvovaginitis is the most common cause and often responds to simple hygiene measures. Awareness of the less common causes of vaginal discharge is essential. Copyright © 2013 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

  6. Legal aspects of thermal discharges

    International Nuclear Information System (INIS)

    Martin, A.J.

    1974-01-01

    An overview of those legal areas which directly affect technical and planning decisions is presented in the form of 2 legal approaches which constrain the indiscriminate release of thermal discharges to receiving waters. One takes the form of private remedies which have traditionally been available to aggrieved parties who are in some way damaged by the harmful discharge. The 2nd approach utilizes the various statutory constraints leading to direct governmental action. It appears that statutory law is playing the prominent role in restricting the temperature to which receiving waters may be raised as a result of such discharges by using effluent limitations and water quality standards. (Water Resour. Abstr.)

  7. An introduction to gas discharges

    CERN Document Server

    Howatson, A M

    2013-01-01

    An Introduction to Gas Discharges: Second Edition aims to provide a compact introduction to the subject of gas discharges, which continues to make both scientific and industrial progress. In this second edition, the author has made minor corrections, rewritten and expanded some sections, used SI units and modernized notions, in hopes of making the book more up to date. Included in the book is a short history of the subject, an introduction that enumerates the types of gas discharges, the fundamental processes, and then moves on to the more specific areas such as the breakdown, the self-sustai

  8. Processing of pure titanium containing titanium-based reinforcing ceramics additives using spark plasma sintering

    Directory of Open Access Journals (Sweden)

    Mondiu Olayinka DUROWOJU

    2017-06-01

    Full Text Available The densification behaviour, microstructural changes and hardness characteristics during spark plasma sintering of CP-Ti reinforced with TiC, TiN, TiCN and TiB2 were investigated. Commercially pure Ti powders were dry mixed with varied amounts (2.5 and 5 wt. % of the ceramic additives using a T2F Turbula mixer for 5 h and at a speed of 49 rpm. The blended composite powders were then sintered using spark plasma sintering system (model HHPD-25 from FCT Germany at a heating rate of 100oC min-1, dwell time of 5 min and sintering temperature of 950ºC. The sintering of CP-Ti was used as a base study to select the proper spark plasma sintering temperature for full density. Densification was monitored through analysis of the recorded punch displacement and the measured density of the sintered samples using Archimedes method. High densities ranging from 97.8% for 5% TiB2 addition to 99.6% for 5% TiCN addition were achieved at a relatively low temperature of 950°C. Microstructural analyses show a uniform distribution of the additives and finer structure showing their inhibitive effect on grain growth. An improved hardness was observed in all the cases with highest values obtained with TiCN as a result of the combined effect of TiC and TiN. A change in the fracture mode from trans granular to intergranular was also observed.

  9. Conversion of a diesel engine to a spark ignition natural gas engine

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    Requirements for alternatives to diesel-fueled vehicles are developing, particularly in urban centers not in compliance with mandated air quality standards. An operator of fleets of diesel- powered vehicles may be forced to either purchase new vehicles or equip some of the existing fleets with engines designed or modified to run on alternative fuels. In converting existing vehicles, the operator can either replace the existing engine or modify it to burn an alternative fuel. Work described in this report addresses the problem of modifying an existing diesel engine to operate on natural gas. Tecogen has developed a technique for converting turbocharged automotive diesel engines to operate as dedicated spark-ignition engines with natural gas fuel. The engine cycle is converted to a more-complete-expansion cycle in which the expansion ratio of the original engine is unchanged while the effective compression ratio is lowered, so that engine detonation is avoided. The converted natural gas engine, with an expansion ratio higher than in conventional spark- ignition natural gas engines, offers thermal efficiency at wide-open- throttle conditions comparable to its diesel counterpart. This allows field conversion of existing engines. Low exhaust emissions can be achieved when the engine is operated with precise control of the fuel air mixture at stoichiometry with a 3-way catalyst. A Navistar DTA- 466 diesel engine with an expansion ratio of 16.5 to 1 was converted in this way, modifying the cam profiles, increasing the turbocharger boost pressure, incorporating an aftercooler if not already present, and adding a spark-ignition system, natural gas fuel management system, throttle body for load control, and an electronic engine control system. The proof-of-concept engine achieved a power level comparable to that of the diesel engine without detonation. A conversion system was developed for the Navistar DT 466 engine. NOx emissions of 1.5 g/bhp-h have been obtained.

  10. Controlling corrosion rate of Magnesium alloy using powder mixed electrical discharge machining

    Science.gov (United States)

    Razak, M. A.; Rani, A. M. A.; Saad, N. M.; Littlefair, G.; Aliyu, A. A.

    2018-04-01

    Biomedical implant can be divided into permanent and temporary employment. The duration of a temporary implant applied to children and adult is different due to different bone healing rate among the children and adult. Magnesium and its alloys are compatible for the biodegradable implanting application. Nevertheless, it is difficult to control the degradation rate of magnesium alloy to suit the application on both the children and adult. Powder mixed electrical discharge machining (PM-EDM) method, a modified EDM process, has high capability to improve the EDM process efficiency and machined surface quality. The objective of this paper is to establish a formula to control the degradation rate of magnesium alloy using the PM-EDM method. The different corrosion rate of machined surface is hypothesized to be obtained by having different combinations of PM-EDM operation inputs. PM-EDM experiments are conducted using an opened-loop PM-EDM system and the in-vitro corrosion tests are carried out on the machined surface of each specimen. There are four operation inputs investigated in this study which are zinc powder concentration, peak current, pulse on-time and pulse off-time. The results indicate that zinc powder concentration is significantly affecting the response with 2 g/l of zinc powder concentration obtaining the lowest corrosion rate. The high localized temperature at the cutting zone in spark erosion process causes some of the zinc particles get deposited on the machined surface, hence improving the surface characteristics. The suspended zinc particles in the dielectric fluid have also improve the sparking efficiency and the uniformity of sparks distribution. From the statistical analysis, a formula was developed to control the corrosion rate of magnesium alloy within the range from 0.000183 mm/year to 0.001528 mm/year.

  11. EXPERIMENTAL DETERMINATION OF TEMPERATURES IN SPARK GENERATED BUBBLES OSCILLATING IN WATER

    Directory of Open Access Journals (Sweden)

    Karel Vokurka

    2017-05-01

    Full Text Available The surface temperatures of the plasma core in the final stages of the first contraction phase of spark-generated bubbles oscillating under ordinary laboratory conditions in a large expanse of water are determined experimentally. The measurement method is based on an analysis of the optical radiation from the bubbles and on the assumption that the plasma core is radiating as a black-body. It is found that the maximum surface temperatures of the plasma core range 4300–8700 K.

  12. Grain growth control and transparency in spark plasma sintered self-doped alumina materials

    International Nuclear Information System (INIS)

    Suarez, M.; Fernandez, A.; Menendez, J.L.; Torrecillas, R.

    2009-01-01

    Doping alumina particles with aluminum alkoxides allows dense spark plasma sintered (SPSed) materials to be obtained that have a refined grain size compared to pure materials, which is critical for their transparency. An optical model considering pore and grain size distributions has been developed to obtain information about porosity in dense materials. This work suggests that the atomic diffusion mechanisms do not depend on the sintering technique. A reduction in the activation energy by a factor of 2 has been found in SPSed materials.

  13. Low jitter spark gap switch for repetitively pulsed parallel capacitor banks

    International Nuclear Information System (INIS)

    Rohwein, G.J.

    1980-01-01

    A two-section air insulated spark gap has been developed for switching multi-kilojoule plus-minus charged parallel capacitor banks which operate continuously at pulse rates up to 20 pps. The switch operates with less than 2 ns jitter, recovers its dielectric strength within 2 to 5 ms and has not shown degraded performance in sequential test runs totaling over a million shots. Its estimated life with copper electrodes is > 10 7 shots. All preliminary tests indicate that the switch is suitable for continuous running multi-kilojoule systems operating to at least 20 pps

  14. Nanostructured tetragonal barium titanate produced by the polyol and spark plasma sintering (SPS) route

    Science.gov (United States)

    Acevedo-Salas, Ulises; Breitwieser, Romain; Gaudisson, Thomas; Nowak, Sophie; Ammar, Souad; Valenzuela, Raúl

    2017-10-01

    There is a great interest to synthesize ferroelectric ceramics both with fine grain size and significant electric properties. Here, we report the preparation of nanostructured tetragonal barium titanate by combining forced hydrolysis of metallic salts in polyol, soft annealing and 650 °C spark plasma sintering under uniaxial pressure of 120 MPa for 5 min. The stabilization of highly dense (density of 90%), nanostructured (grains about 50 nm) tetragonal barium titanate ceramic was achieved. The produced ceramic exhibited ferroelectric behavior and a dielectric permittivity of 3600 at 1 kHz and room temperature.

  15. Effect of cryogenic milling on Al7075 prepared by spark plasma sintering method.

    Czech Academy of Sciences Publication Activity Database

    Lukáč, František; Chráska, Tomáš; Molnárová, O.; Málek, P.; Cinert, Jakub

    2017-01-01

    Roč. 32, S1 (2017), S221-S224 ISSN 0885-7156. [European Powder Diffraction Conference (EPDIC) /15./. Bari, 12.06.2016-15.06.2016] R&D Projects: GA ČR(CZ) GA15-15609S Institutional support: RVO:61389021 Keywords : Intermetallic precipitates * cryogenic milling * powder metallurgy * ultrafine-grained materials * Al7075 alloy Subject RIV: JG - Metallurgy OBOR OECD: Materials engineering Impact factor: 0.674, year: 2016 https://www.cambridge.org/core/journals/powder-diffraction/article/effect-of-cryogenic-milling-on-al7075-prepared-by-spark-plasma-sintering-method/17E9F722BAFD428BA7310194FEE551C6

  16. Barium titanate nanometric polycrystalline ceramics fired by spark plasma sintering.

    Czech Academy of Sciences Publication Activity Database

    Ctibor, Pavel; Sedláček, J.; Ryukhtin, Vasyl; Cinert, Jakub; Lukáč, František

    2016-01-01

    Roč. 42, č. 14 (2016), s. 15989-15993 ISSN 0272-8842 R&D Projects: GA ČR GB14-36566G; GA MŠk LM2015056 Institutional support: RVO:61389021 ; RVO:61389005 Keywords : BaTiO3 * Spark plasma sintering * Electrical properties Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass; JH - Ceramics, Fire-Resistant Materials and Glass (UJF-V) Impact factor: 2.986, year: 2016 http://www.sciencedirect.com/science/article/pii/S0272884216311695

  17. Surprising synthesis of nanodiamond from single-walled carbon nanotubes by the spark plasma sintering process

    Science.gov (United States)

    Mirzaei, Ali; Ham, Heon; Na, Han Gil; Kwon, Yong Jung; Kang, Sung Yong; Choi, Myung Sik; Bang, Jae Hoon; Park, No-Hyung; Kang, Inpil; Kim, Hyoun Woo

    2016-10-01

    Nanodiamond (ND) was successfully synthesized using single-walled carbon nanotubes (SWCNTs) as a pure solid carbon source by means of a spark plasma sintering process. Raman spectra and X-ray diffraction patterns revealed the generation of the cubic diamond phase by means of the SPS process. Lattice-resolved TEM images confirmed that diamond nanoparticles with a diameter of about ˜10 nm existed in the products. The NDs were generated mainly through the gas-phase nucleation of carbon atoms evaporated from the SWCNTs. [Figure not available: see fulltext.

  18. Numerical modelling of barrier discharge

    International Nuclear Information System (INIS)

    Kozlov, K.V.

    1990-01-01

    A survey is given of the theory of the barrier discharge in oxygen at atmospheric pressure. The discharge consists of a number of randomly distributed microdischarges of nanosecond duration. This complicated space-time structure must be taken into account in any numerical model of the barrier discharge. In a single discharge channel, three consequent phases can be distinguished; 1) electric breakdown and electron-time-scale processes; 2) ion drift and ion-time-scale processes; 3) slow chemical processes, diffusion of chemical products and heat transfer. The scheme of such a three-phase model is presented and the results of simulation are discussed and compared with experimental data. (J.U.) 9 figs., 15 refs

  19. Microwave discharges in capillary tubes

    International Nuclear Information System (INIS)

    Dervisevic, Emil

    1984-01-01

    This research thesis aims at being a contribution to the study of microwave discharge by a surface wave, and more precisely focusses on the discharge in capillary tubes filled with argon. The author first present theoretical models which describe, on the one hand, the propagation of the surface wave along the plasma column, and, on the other hand, longitudinal and radial profiles of the main discharge characteristics. The second part addresses the study of the influence of parameters (gas pressure and tube radius) on discharge operation and characteristics. Laws of similitude as well as empirical relationships between argon I and argon II emission line intensities, electron density, and electric field in the plasma have been established [fr

  20. Gram stain of urethral discharge

    Science.gov (United States)

    Urethral discharge Gram stain; Urethritis - Gram stain ... Augenbraun MH, McCormack WM. Urethritis. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, Updated Edition . ...

  1. Discharge cell for ozone generator

    Science.gov (United States)

    Nakatsuka, Suguru

    2000-01-01

    A discharge cell for use in an ozone generator is provided which can suppress a time-related reduction in ozone concentration without adding a catalytic gas such as nitrogen gas to oxygen gas as a raw material gas. The discharge cell includes a pair of electrodes disposed in an opposed spaced relation with a discharge space therebetween, and a dielectric layer of a three-layer structure consisting of three ceramic dielectric layers successively stacked on at least one of the electrodes, wherein a first dielectric layer of the dielectric layer contacting the one electrode contains no titanium dioxide, wherein a second dielectric layer of the dielectric layer exposed to the discharge space contains titanium dioxide in a metal element ratio of not lower than 10 wt %.

  2. Total colectomy or proctocolectomy - discharge

    Science.gov (United States)

    ... Ileostomy and your diet Ileostomy - caring for your stoma Ileostomy - changing your pouch Ileostomy - discharge Ileostomy - what to ask your doctor Low-fiber diet Surgical wound care - open Types of ileostomy Review Date 9/17/ ...

  3. Sparking Interest

    Science.gov (United States)

    Guth, Douglas J.

    2018-01-01

    Community colleges are attempting to bridge America's widening blue-collar skills gap through workforce development programs promising living-wage jobs that don't require four years of college. While trade, construction and manufacturing companies are starving for talented workers, these fields also suffer from an image problem, one fueled by…

  4. Radioactive discharges from Sellafield (UK)

    International Nuclear Information System (INIS)

    Pentreath, R.J.

    1985-01-01

    This study of low-level liquid radioactive discharges from the British Nuclear Fuels Ltd Sellafield site into the eastern basin of the Irish Sea, prepared on the basis of existing publications and documents, reviews chemical forms and rate of discharges, physical oceanography, sediment distribution and fisheries of the Irish Sea, behaviour of radionuclides in seawater, association with sedimentary materials, accumulation of radionuclides by biological materials, environmental monitoring, surveillance and assessment of radiation exposure of the public and impact on the environment

  5. Vaginal Discharge: What's Normal, What's Not

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Vaginal Discharge: What's Normal, What's Not KidsHealth / For Teens / Vaginal Discharge: What's Normal, What's Not Print Normal vaginal discharge ...

  6. Ballooning stability of JET discharges

    International Nuclear Information System (INIS)

    Huysmans, G.T.A.; Goedbloed, J.P.; Galvao, R.M.O.; Lazzaro, E.; Smeulders, P.

    1989-01-01

    Conditions under which ballooning modes are expected to be excited have recently been obtained in two different types of discharges in JET. In the first type, extremely large pressure gradients have been produced in the plasma core through pellet injections in the current rise phase followed by strong additional heating. In the second type, the total pressure of the discharge is approaching the Troyon limit. The stability of these discharges with respect to the ideal MHD ballooning modes has been studied with the stability code HBT. The equilibria are reconstructed with the IDENTC code using the external magnetic measurements and the experimental pressure profile. The results show that the evaluated high beta discharge is unstable in the central region of the plasma. This instability is related to the low shear and not to a large pressure gradient, as expected at the Troyon limit. In the pellet discharges the regions with the large pressure gradients are unstable to ballooning modes at the time of the beta decay, which ends the period of enhanced performance. The maximum pressure gradient in these discharges is limited by the boundary of the first region of stability. The observed phenomena at the beta decay are similar to those observed at the beta limit in DIII-D and TFTR. (author)

  7. Interferometric fiber-optic sensor embedded in a spark plug for in-cylinder pressure measurement in engines.

    Science.gov (United States)

    Bae, Taehan; Atkins, Robert A; Taylor, Henry F; Gibler, William N

    2003-02-20

    Pressure sensing in an internal combustion engine with an intrinsic fiber Fabry-Perot interferometer (FFPI) integrated with a spark plug is demonstrated for the first time. The spark plug was used for the ignition of the cylinder in which it was mounted. The FFPI element, protected with a copper/gold coating, was embedded in a groove in the spark-plug housing. Gas pressure inthe engine induced longitudinal strain in this housing, which was also experienced by the fiber-optic sensing element. The sensor was monitored with a signal conditioning unit containing a chirped distributed-feedback laser. Pressure sensitivities as high as 0.00339 radians round-trip phase shift per pounds per square inch of pressure were observed. Measured pressure versus time traces showed good agreement with those from a piezoelectric reference sensor mounted in the same engine cylinder.

  8. The spark counting of etched fission-fragment tracks in polycarbonate for a personal neutron dosimetry system

    International Nuclear Information System (INIS)

    Harrison, K.G.; Hancock, I.B.; Holt, P.D.; Wylie, J.W.

    1977-10-01

    A new type of personal neutron dosimeter, in which neutron-induced fissions in a thin 237 Np foil are detected by a polycarbonate track-detector, is under development at Harwell for use in a nuclear-fuel reprocessing plant. As part of the development programme, an experimental dosimeter, etching facility and spark counter have been used to study the spark-counting method for counting fission-fragment tracks in polycarbonate. Emphasis has been placed on developing operating procedures for the counter consistent with good overall reproducibility. Existing methods for the optimizing and testing of spark counters is briefly reviewed and a practical operational testing procedure is devised. The optimized system is found to be relatively foolproof in operation and gives good results in unskilled use as well as under carefully-controlled laboratory conditions. (author)

  9. Quantitative Determination of the Breakdown Field of Air from Van de Graaff Generator Discharge

    Science.gov (United States)

    Beach, John; Chartrand, Bridget; Gallagher, Hugh

    2016-03-01

    The Van de Graaff generator (VG) is ubiquitous in electrostatic demonstrations because of the large static charge and dramatic sparks produced. We have developed a novel technique for determining the breakdown field of air using the VG. When a spark occurs, the force of attraction between the VG and a discharge sphere suspended above it is measured by a Pasco force sensor. At this time the charge is not symmetric but pulled towards the near side of the spheres by mutual attraction. In order to interpret the measured force in terms of the breakdown field, an accurate model of the charge distribution is needed. Using the method of images for a spherical conductor in an iterative fashion we can provide this model. The electric field in the vicinity of the spheres is then calculated from the charge distribution and its maximum value is the breakdown field. In preliminary work, we determined the breakdown field to be 3.1x106 N/C at 24.9 C and 18% relative humidity. We will report our most recent determination of the breakdown field using this method and discuss the validity of the results in terms of accepted values, experimental limitations and sensitivity to the charge distribution model.

  10. Prebiotic Synthesis in Volcanic Discharges: Exposing Ash to Volcanic/Primordial Gas Atmospheres

    Science.gov (United States)

    Scheu, B.; Dingwell, D. B.; Cimarelli, C.; Bada, J.; Chalmers, J. H.; Burton, A. S.

    2017-12-01

    Few topics in natural science are as heavily debated as context for the emergence of life on Earth more than 3.5 billion years ago. The spark discharge experiments by Miller (1953) are widely recognized as the first efficient abiotic synthesis of organic compounds under simulated primitive Earth conditions; however, since then our understanding of conditions on the early Earth have significantly advanced. Still, considerable uncertainty remains regarding when, where and how the raw materials needed for prebiotic reactions and molecular evolution originated. Recently volcanic lightning has been successfully reproduced in rapid decompression experiments, showing a direct relation between amount of electrical discharges and the abundance of finer ash ejected. This correlation suggests that efficient fragmentation and particle clustering in the plume provide favorable conditions for charge generation and discharge. In the context of the origin of life, volcanic lightning is of special interest because within volcanic plumes the volcanic gases will mix with the primordial atmosphere, widening the possible gas spectrum. Here we present a first study on volcanic discharges generated from the energetic ejection of volcanic ash into different controlled atmospheres. Ash from Sakurajima volcano (Japan), well known for the electrical activity associated with its frequent explosive eruptions, was loaded in our experimental volcano (a shock-tube-based apparatus), slowly pressurized and ejected into atmospheres of various compositions (N2, CH4, NH3, CO2). We monitored ash ejection as well as charge generation and discharges. The recollected ash was analyzed for interesting prebiotic compounds. Analyses indicated that simple amino acids such as glycine were synthesized in the experiments as long as there was a reduced gas (either ammonia or methane) present. We are now carrying out a systematic series of analyses to determine whether essential prebiotic reagents are generated

  11. Fundamental Studies of Ignition Process in Large Natural Gas Engines Using Laser Spark Ignition

    Energy Technology Data Exchange (ETDEWEB)

    Azer Yalin; Bryan Willson

    2008-06-30

    Past research has shown that laser ignition provides a potential means to reduce emissions and improve engine efficiency of gas-fired engines to meet longer-term DOE ARES (Advanced Reciprocating Engine Systems) targets. Despite the potential advantages of laser ignition, the technology is not seeing practical or commercial use. A major impediment in this regard has been the 'open-path' beam delivery used in much of the past research. This mode of delivery is not considered industrially practical owing to safety factors, as well as susceptibility to vibrations, thermal effects etc. The overall goal of our project has been to develop technologies and approaches for practical laser ignition systems. To this end, we are pursuing fiber optically coupled laser ignition system and multiplexing methods for multiple cylinder engine operation. This report summarizes our progress in this regard. A partial summary of our progress includes: development of a figure of merit to guide fiber selection, identification of hollow-core fibers as a potential means of fiber delivery, demonstration of bench-top sparking through hollow-core fibers, single-cylinder engine operation with fiber delivered laser ignition, demonstration of bench-top multiplexing, dual-cylinder engine operation via multiplexed fiber delivered laser ignition, and sparking with fiber lasers. To the best of our knowledge, each of these accomplishments was a first.

  12. THE EFFECT OF VARIABLE COMPRESSION RATIO ON FUEL CONSUMPTION IN SPARK IGNITION ENGINES

    Directory of Open Access Journals (Sweden)

    Yakup SEKMEN

    2002-02-01

    Full Text Available Due to lack of energy sources in the world, we are obliged to use our current energy sources in the most efficient way. Therefore, in the automotive industry, research works to manufacture more economic cars in terms of fuelconsumption and environmental friendly cars, at the same time satisfying the required performance have been intensively increasing. Some positive results have been obtained by the studies, aimed to change the compression ratio according to the operating conditions of engine. In spark ignition engines in order to improve the combustion efficiency, fuel economy and exhaust emission in the partial loads, the compression ratio must be increased; but, under the high load and low speed conditions to prevent probable knock and hard running compression ratio must be decreased slightly. In this paper, various research works on the variable compression ratio with spark ignition engines, the effects on fuel economy, power output and thermal efficiency have been investigated. According to the results of the experiments performed with engines having variable compression ratio under the partial and mid-load conditions, an increase in engine power, a decrease in fuel consumption, particularly in partial loads up to 30 percent of fuel economy, and also severe reductions of some exhaust emission values were determined.

  13. High quality new type spark plug pressure sensor; Koseino plug gata shiatsu sensor ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Urakawa, H.; Yanagihara, S.; Kawa, T. [Tsukasa Sokken Co. Ltd., Tokyo (Japan); Enomoto, Y. [Musashi Institute of Technology, Tokyo (Japan); Sato, T. [Dai Ichi Institute of Technology, Kagoshima (Japan); Gotthard, E.

    1998-05-01

    Investigations were made on a spark plug type pressure sensor using GaPO4 piezoelectric material developed recently by AVL Corporation. This sensor has the ignition electrode installed decentered to assure the installing position for the pressure sensor, where the small pressure sensor with a diameter of 4.4 mm, model GU12P is installed on the side. Experiments were performed on this sensor, a water cooled sensor for comparison, and a cooling-free type sensor for reference. The engine was operated at an outlet cooling water temperature maintained constant at 80 degC, and experimented in a normal combustion condition with full load at 2000 rpm and 4000 rpm, in a knocking condition with full load at 2000 rpm, and in a transient condition from full load at 4000 rpm to no load at 1300 rpm. As a result, it was made clear that the spark plug type pressure sensor showed an output of the same level as that with the water cooled sensor in the normal combustion pressure. Load change drift under the transient condition was found as good as 2.5% FS at maximum. No effect of columnar vibration was discovered, and a knocking waveform of 14 kHz was observed. 6 refs., 12 figs., 1 tab.

  14. Synthesis of dense yttrium-stabilised hafnia pellets for nuclear applications by spark plasma sintering

    International Nuclear Information System (INIS)

    Tyrpekl, Vaclav; Holzhäuser, Michael; Hein, Herwin; Vigier, Jean-Francois; Somers, Joseph; Svora, Petr

    2014-01-01

    Graphical abstract: Densification of HfO 2 –Y 2 O 3 micro-beads by Spark Plasma Sintering High density pellets with homogenous distribution of Hf and Y serve as neutron absorbers. - Abstract: Dense yttrium–stabilised hafnia pellets (91.35 wt.% HfO 2 and 8.65 wt.% Y 2 O 3 ) were prepared by spark plasma sintering consolidation of micro-beads synthesised by the “external gelation” sol–gel technique. This technique allows a preparation of HfO 2 –Y 2 O 3 beads with homogenous yttria–hafnia solid solution. A sintering time of 5 min at 1600 °C was sufficient to produce high density pellets (over 90% of the theoretical density) with significant reproducibility. The pellets have been machined in a lathe to the correct dimensions for use as neutron absorbers in an experimental test irradiation in the High Flux Reactor (HFR) in Petten, Holland, in order to investigate the safety of americium based nuclear fuels

  15. Zinc sparks induce physiochemical changes in the egg zona pellucida that prevent polyspermy.

    Science.gov (United States)

    Que, Emily L; Duncan, Francesca E; Bayer, Amanda R; Philips, Steven J; Roth, Eric W; Bleher, Reiner; Gleber, Sophie C; Vogt, Stefan; Woodruff, Teresa K; O'Halloran, Thomas V

    2017-02-20

    During fertilization or chemically-induced egg activation, the mouse egg releases billions of zinc atoms in brief bursts known as 'zinc sparks.' The zona pellucida (ZP), a glycoprotein matrix surrounding the egg, is the first structure zinc ions encounter as they diffuse away from the plasma membrane. Following fertilization, the ZP undergoes changes described as 'hardening', which prevent multiple sperm from fertilizing the egg and thereby establish a block to polyspermy. A major event in zona hardening is cleavage of ZP2 proteins by ovastacin; however, the overall physiochemical changes contributing to zona hardening are not well understood. Using X-ray fluorescence microscopy, transmission and scanning electron microscopy, and biological function assays, we tested the hypothesis that zinc release contributes to ZP hardening. We found that the zinc content in the ZP increases by 300% following activation and that zinc exposure modulates the architecture of the ZP matrix. Importantly, zinc-induced structural changes of the ZP have a direct biological consequence; namely, they reduce the ability of sperm to bind to the ZP. These results provide a paradigm-shifting model in which fertilization-induced zinc sparks contribute to the polyspermy block by altering conformations of the ZP matrix. This adds a previously unrecognized factor, namely zinc, to the process of ZP hardening.

  16. Spark Ignition Engine Combustion, Performance and Emission Products from Hydrous Ethanol and Its Blends with Gasoline

    Directory of Open Access Journals (Sweden)

    Musaab O. El-Faroug

    2016-11-01

    Full Text Available This paper reviews the serviceability of hydrous ethanol as a clean, cheap and green renewable substitute fuel for spark ignition engines and discusses the comparative chemical and physical properties of hydrous ethanol and gasoline fuels. The significant differences in the properties of hydrous ethanol and gasoline fuels are sufficient to create a significant change during the combustion phase of engine operation and consequently affect the performance of spark-ignition (SI engines. The stability of ethanol-gasoline-water blends is also discussed. Furthermore, the effects of hydrous ethanol, and its blends with gasoline fuel on SI engine combustion characteristics, cycle-to-cycle variations, engine performance parameters, and emission characteristics have been highlighted. Higher water solubility in ethanol‑gasoline blends may be obviously useful and suitable; nevertheless, the continuous ability of water to remain soluble in the blend is significantly affected by temperature. Nearly all published engine experimental results showed a significant improvement in combustion characteristics and enhanced engine performance for the use of hydrous ethanol as fuel. Moreover, carbon monoxide and oxides of nitrogen emissions were also significantly decreased. It is also worth pointing out that unburned hydrocarbon and carbon dioxide emissions were also reduced for the use of hydrous ethanol. However, unregulated emissions such as acetaldehyde and formaldehyde were significantly increased.

  17. Effect of intake manifold water injection on a natural gas spark ignition engine: an experimental study

    Science.gov (United States)

    Arruga, H.; Scholl, F.; Kettner, M.; Amad, O. I.; Klaissle, M.; Giménez, B.

    2017-10-01

    Design and development of gas CHP (combined heat and power) engines are strongly influenced by the progressively more severe European NOx emissions normative. Water injection represents a promising approach to reduce these emissions while attaining high engine efficiency. In this work, the effect of intake manifold water injection on combustion parameters and performance of a single-cylinder naturally aspirated natural gas spark ignition engine is presented. First, the most appropriate injector was selected, using a spray test bed. Subsequently, engine experiments at constant indicated mean effective pressure (IMEP) and engine speed were conducted with water-fuel ratios of 0.1 to 0.3. IMEP was kept constant at about 6.3 bar by adjusting both air-fuel ratio and spark timing. A NOx reduction of 0.2 g/kWhi (15 %) for a constant ISFC of about 204 g/kWhi was achieved. In the low NOx regime, water injection allows for an improvement of the NOx-ISFC trade-off, while leading to poor fuel consumption at same NOx in the high efficiency regime. Furthermore, water injection implies a reduction of intake mixture temperature, lengthened burning delay and combustion duration and a moderate increase of combustion instability.

  18. Trace element determinations in uranium bearing minerals and rocks by spark source mass spectrometry

    International Nuclear Information System (INIS)

    Luck, J.; Szacki, W.; Pluhar, E.

    1981-01-01

    Spark source mass spectrometry has been used in the multielemental analyses in the samples: BIR, DNC, and W-2 of the U.S. Geological Survey (USGS). The concentrations for up to 23 trace elements could be determined depending on the concentration level and matrix composition. The USGS standards W-1 and BCR-1 were used as multi-elemental standards to evaluate the necessary sensitivity factors. The determinations of U and Th concentrations of DL-1a (Canada Centre for Mineral and Energy Technology, CANMET) are based on sensitivity factors of CANMET DH-1, BL-1, BL-2, BL-3, and BL-4 standard material. The agreement between our U and Th values and those concentration values supplied from CANMET at the end of the round robin program for the standardization was found to be good. The application of spark source mass spectrometry is demonstrated by determining the concentrations of 10 geochemical relevant elements in two drill cores of a uranium deposit and neighbouring rocks. (orig.) [de

  19. Distributed Nonparametric and Semiparametric Regression on SPARK for Big Data Forecasting

    Directory of Open Access Journals (Sweden)

    Jelena Fiosina

    2017-01-01

    Full Text Available Forecasting in big datasets is a common but complicated task, which cannot be executed using the well-known parametric linear regression. However, nonparametric and semiparametric methods, which enable forecasting by building nonlinear data models, are computationally intensive and lack sufficient scalability to cope with big datasets to extract successful results in a reasonable time. We present distributed parallel versions of some nonparametric and semiparametric regression models. We used MapReduce paradigm and describe the algorithms in terms of SPARK data structures to parallelize the calculations. The forecasting accuracy of the proposed algorithms is compared with the linear regression model, which is the only forecasting model currently having parallel distributed realization within the SPARK framework to address big data problems. The advantages of the parallelization of the algorithm are also provided. We validate our models conducting various numerical experiments: evaluating the goodness of fit, analyzing how increasing dataset size influences time consumption, and analyzing time consumption by varying the degree of parallelism (number of workers in the distributed realization.

  20. Effect of the duty cycle on the spark-plug plasma synthetic jet actuator

    Directory of Open Access Journals (Sweden)

    Seyhan Mehmet

    2016-01-01

    Full Text Available A promising novel actuator called Spark-Plug Plasma Synthetic Jet (SPSJ has been developed in Atmospheric Plasma Research Laboratory at Niğde University. It generates electrothermally high synthetic jet velocity by using high voltage. SPSJ actuator can be utilized to be an active flow control device having some advantages such as no moving parts, low energy consumption and easy to integrate the system. This actuator consists of two main components: semi-surface spark plug (NGK BUHW as an anode electrode and a cap having an orifice as a cathode electrode. The cap, having a jet exit orifice diameter of 2 mm, has diameter of 4.4 mm and height of 4.65 mm. This study presents the characteristics of SPSJ actuator by using the hot wire anemometer in order to approximately determine jet velocity in quiescent air. Peak velocity as high as 180 m/s was obtained for fe= 100 and duty cycle 50%. The flow visualization indicated that the actuator’s jet velocity is enough to penetrate the developed boundary layer.

  1. Classification of electrical discharges in DC Accelerators

    Science.gov (United States)

    Banerjee, Srutarshi; Deb, A. K.; Rajan, Rehim N.; Kishore, N. K.

    2016-08-01

    Controlled electrical discharge aids in conditioning of the system while uncontrolled discharges damage its electronic components. DC Accelerator being a high voltage system is no exception. It is useful to classify electrical discharges according to the severity. Experimental prototypes of the accelerator discharges are developed. Photomultiplier Tubes (PMTs) are used to detect the signals from these discharges. Time and Frequency domain characteristics of the detected discharges are used to extract features. Machine Learning approaches like Fuzzy Logic, Neural Network and Least Squares Support Vector Machine (LSSVM) are employed to classify the discharges. This aids in detecting the severity of the discharges.

  2. Classification of electrical discharges in DC Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Srutarshi, E-mail: sruban.stephens@gmail.com [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Deb, A.K. [Department of Electrical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India); Rajan, Rehim N. [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Kishore, N.K. [Department of Electrical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)

    2016-08-11

    Controlled electrical discharge aids in conditioning of the system while uncontrolled discharges damage its electronic components. DC Accelerator being a high voltage system is no exception. It is useful to classify electrical discharges according to the severity. Experimental prototypes of the accelerator discharges are developed. Photomultiplier Tubes (PMTs) are used to detect the signals from these discharges. Time and Frequency domain characteristics of the detected discharges are used to extract features. Machine Learning approaches like Fuzzy Logic, Neural Network and Least Squares Support Vector Machine (LSSVM) are employed to classify the discharges. This aids in detecting the severity of the discharges.

  3. Comparison the Impact of Spark Motor Program and Basketball Techniques on Improving Gross Motor Skills in Educable Intellectually Disabled Boys

    Directory of Open Access Journals (Sweden)

    Hashem Faal Moghanlo

    2014-09-01

    Full Text Available Background & objectives : Different types of practises are known for improving motor skills in intellectually disabled boys. The purpose of this study was to compar e the impact of spark motor program and basketball on improving of gross motor skills in this people.   Methods: In this semi-experimental study , from 98 educable intellectually disabled students who studied in special school in Urmia, 30 children ( age range of 9 to 13 years and IQ mean 64.4 were selected objectively and divided in three groups (2 experimental and 1 control based on pre - test. BOTMP was used as a measurement of motor ability. Selected motor program (Spark motor program including strengthening training, games, sports and basketball techniques was performed for 24 sessions. T-tests (dependent and co-variance were used to comparison of results.   Results: In Spark group after 24 sessions, there were significant effects on balance (p= 0.000, bilateral coordination (p=0.000 and strength (p=0.001. There was no significant effect in agility and speed (p= 0.343 in basketball techniques group after 24 sessions, there were significant effects in agility and speed (p= 0.001, balance (p= 0.000, bilateral coordination (p= 0.013 and strength (p= 0.007.   Conclusion: Based on the results of this study, it can be claimed that the Spark program and basketball techniques improve gross motor skills in educable intellectually disabled students. We also found a significant difference between the Spark program and basketball techniques efficacy on the improved skills. Furthermore, the efficacy of Spark program was significantly higher than basketball techniques (p<0.05.

  4. Development of laser-induced fluorescence for precombustion diagnostics in spark-ignition engines

    Energy Technology Data Exchange (ETDEWEB)

    Neij, H.

    1998-11-01

    Motivated by a desire to understand and optimize combustion in spark-ignition (SI) engines, laser techniques have been developed for measurement of fuel and residual gas, respectively, in the precombustion mixture of an operating SI engine. The primary objective was to obtain two-dimensional, quantitative data in the vicinity of the spark gap at the time of ignition. A laser-induced fluorescence (LIF) technique was developed for fuel visualization in engine environments. Since the fluorescence signal from any commercial gasoline fuel would be unknown to its origin, with an unpredictable dependence on collisional partners, pressure and temperature, a non-fluorescent base fuel - isooctane - was used. For LIF detection, a fluorescent species was added to the fuel. An additive not commonly used in this context - 3-pentanone - was chosen based on its suitable vaporization characteristics and fluorescent properties. The LIF technique was applied to an optically accessible research engine. By calibration, the fluorescence signal from the additive was converted to fuel-to-air equivalence ratio ({phi}). The accuracy and precision of the acquired data were assessed. A statistical evaluation revealed that the spatially averaged equivalence ratio around the spark plug had a significant impact on the combustion event. The strong correlation between these two quantities suggested that the early combustion was sensitive to large-scale inhomogeneities in the precombustion mixture. A similar LIF technique, using acetone as a fluorescent additive in methane, was applied to a combustion cell for ion current evaluation. The local equivalence ratio around the spark gap at the time of ignition was extracted from LIF data. Useful relations were identified between different ion current parameters and the local equivalence ratio, although the impact of the flow field, the fuel type, and the electrode geometry were identified as areas for future research. A novel fuel - dimethyl ether (DME

  5. Identification of Knock in NACA High-Speed Photographs of Combustion in a Spark-Ignition Engine

    Science.gov (United States)

    1943-01-01

    brilliancy control of the oscillo- graph beam was arranged in such a way that the beam would normally be invisible but, when tripped by a contactor at the...oscillator was used. The engine was stopped immediately after fining and the brilliancy control was agg tripped to give a single sweep of the...a spark-ignltfon engine wfth IIght hmcL F@ m pemmt S-1 with XI p?rcent M-z fear -k plaga ; spark advanm, loft-bnnd PltW 2’7’. OthW thiw phla m B

  6. THE EFFECT OF GASOLINE-LIKE FUEL PRODUCED FROM WASTE AUTOMOBILE TIRES ON EMISSIONS IN SPARK-IGNITION ENGINES

    OpenAIRE

    ÖZTOP, H. F.; VAROL, Y.; ALTUN, Ş.; FIRAT, M.

    2016-01-01

    In the present paper, the effect of Gasoline-Like Fuel (GLF) on emissions was investigated for direct injection spark-ignited engine. The GLF was obtained from waste automobile tires by using the pyrolysis. The tires are installed to oven without any procedure such as cutting, melding etc. Obtained GLF was then used in a four-cylinder, four-stroke, water-cooled and direct injection spark-ignited engine as blended with unleaded gasoline from 0% to 60% with an increment of 10%. Engine tests res...

  7. Powder-metallurgy preparation of NiTi shape-memory alloy using mechanical alloying and spark-plasma sintering.

    Czech Academy of Sciences Publication Activity Database

    Novák, P.; Moravec, H.; Vojtěch, V.; Knaislová, A.; Školáková, A.; Kubatík, Tomáš František; Kopeček, Jaromír

    2017-01-01

    Roč. 51, č. 1 (2017), s. 141-144 ISSN 1580-2949 R&D Projects: GA ČR(CZ) GA14-03044S Institutional support: RVO:61389021 ; RVO:68378271 Keywords : mechanical alloying * spark plasma sintering * NiTi * shape memory alloy Subject RIV: JG - Metallurgy; JG - Metallurgy (FZU-D) OBOR OECD: Materials engineering ; Materials engineering (FZU-D) Impact factor: 0.436, year: 2016 https://www.researchgate.net/publication/313900224_Powder-metallurgy_preparation_of_NiTi_shape-memory_alloy_using_mechanical_alloying_and_spark-plasma_sintering

  8. LASER RADIATION SCATTERING: Properties of laser radiation scattering by a laser-induced spark plasma revisited after 40 years

    Science.gov (United States)

    Malyutin, A. A.

    2008-05-01

    Experimental studies of a laser-induced spark produced in air by 1.05-μm, 100-ns pulses with spatial TEM00, TEM01 and TEM02 modes are described. It is found that when the spark is observed at an angle of 90° to the laser beam axis, the scattered radiation has the maximal intensity outside the beam waist. The intensity ratio of the scattered laser radiation for two orthogonal polarisations is ≈100, and the spatial structures of their depolarisation considerably differ. These properties are explained by using a model of the Fresnel reflection from the spherical front of the plasma—undisturbed gas interface.

  9. Multi-pin-to-plate atmospheric glow discharge for the removal of volatile organic compounds in waste air

    International Nuclear Information System (INIS)

    Vertriest, R; Morent, R; Dewulf, J; Leys, C; Langenhove, H van

    2003-01-01

    A DC-excited atmospheric pressure glow discharge in a multi-pin-to-plate electrode configuration is applied to the removal of trichloroethylene (TCE) in air. A removal fraction of up to 47% is obtained at an energy density of 35 J litre -1 (air flow rate: 60 m 3 h -1 ; residence time: 50 ms; TCE inlet concentration: 120 ppm; temperature: 298 K). The addition of TCE increases the discharge impedance and improves the uniformity of the current distribution in the direction of the gas flow. In the investigated inlet concentration range (0-160 ppm), no influence of the TCE admixture is observed on the corona-to-glow and glow-to-spark threshold currents. Experiments with other volatile organic compounds (VOCs) reveal that molecules containing a double carbon bond have the lowest energy requirement for decomposition

  10. The source of X-rays and high-charged ions based on moderate power vacuum discharge with laser triggering

    Directory of Open Access Journals (Sweden)

    Alkhimova Mariya A.

    2015-06-01

    Full Text Available The source of X-ray radiation with the energy of quanta that may vary in the range hν = 1÷12 keV was developed for studies in X-ray interaction with matter and modification of solid surfaces. It was based on a vacuum spark discharge with the laser triggering. It was shown in our experiments that there is a possibility to adjust X-ray radiation spectrum by changing the configuration of the electrode system when the energy stored in the capacitor is varied within the range of 1÷17 J. A comprehensive study of X-ray imaging and quanta energy was carried out. These experiments were carried out for the case of both direct and reverse polarity of the voltage on the electrodes. Additionally, ion composition of plasma created in a laser-triggered vacuum discharge was analyzed. Highly charged ions Zn(+21, Cu(+20 and Fe(+18 were observed.

  11. Evaluation of the contact switch materials in high voltage power supply for generate of underwater shockwave by electrical discharge

    Directory of Open Access Journals (Sweden)

    K Higa

    2016-10-01

    Full Text Available We have developed the high voltage power-supply unit by Cockcroft-Walton circuit for ingenerate high pressure due to underwater shockwave by electrical discharge. This high voltage power supply has the problem of the metal contact switch operation that contact switch stop by melting and bonding due to electrical spark. We have studied the evaluation of materials of contact switch for the reducing electrical energy loss and the problem of contact switch operation. In this research, measurement of discharge voltage and high pressure due to underwater shockwave was carried out using the contact switch made of different materials as brass plate, brass-carbon plate-brass and carbon block. The contact switch made of carbon is effective to reduce energy loss and problem of contactor switch operation.

  12. Study of Corona Discharge on 160 KeV, 10 mA Electron Accelerator Facility Using FEM

    International Nuclear Information System (INIS)

    Ghazali, Abu Bakar Mhd; Sobri, Rokiah Mohd

    2008-01-01

    This paper describes a method to verify the overall design of our electron accelerator. It is free from corona or spark discharge phenomenon. This locally designed electron accelerator facility is located at Nuclear Malaysia Complex, Bangi, Selangor. In this study, we describe the geometry of the pressure vessel filled with SF 6 gas at 2 atm to enclose the high voltage area of the accelerating tube. The Poisson's equation is used to calculate the contours of the electric field that is created between the cathode of -160 kV maximum and the wall of the vessel. The nearest sharp edge between the cathode and the pressure wall is 163 mm apart. The calculation is based on finite element method (FEM) for electrostatic charges in order to obtain an electric field contour in two-dimensional plane. We found that the surface charge density of the cathode is 1.1x10 -5 C/m 2 for the corona glowing seen at -90 kV. Moreover, the highest electric field near to (about 5 mm from) the sharp edge is about 2.7 MV/m, which is less than the dielectric strength of SF 6 gas, i.e. 6 MV/m and therefore, it proved that our design of the pressure vessel is save from corona or spark discharges

  13. Influence of air flow parameters on nanosecond repetitively pulsed discharges in a pin-annular electrode configuration

    KAUST Repository

    Heitz, Sylvain A

    2016-03-16

    The effect of various air flow parameters on the plasma regimes of nanosecond repetitively pulsed (NRP) discharges is investigated at atmospheric pressure. The two electrodes are in a pin-annular configuration, transverse to the mean flow. The voltage pulses have amplitudes up to 15 kV, a duration of 10 ns and a repetition frequency ranging from 15 to 30 kHz. The NRP corona to NRP spark (C-S) regime transition and the NRP spark to NRP corona (S-C) regime transition are investigated for different steady and harmonically oscillating flows. First, the strong effect of a transverse flow on the C-S and S-C transitions, as reported in previous studies, is verified. Second, it is shown that the azimuthal flow imparted by a swirler does not affect the regime transition voltages. Finally, the influence of low frequency harmonic oscillations of the air flow, generated by a loudspeaker, is studied. A strong effect of frequency and amplitude of the incoming flow modulation on the NRP plasma regime is observed. Results are interpreted based on the cumulative effect of the NRP discharges and an analysis of the residence times of fluid particles in the inter-electrode region. © 2016 IOP Publishing Ltd.

  14. 40 CFR Table 1a to Subpart Zzzz of... - Emission Limitations for Existing, New, and Reconstructed Spark Ignition, 4SRB Stationary RICE...

    Science.gov (United States)

    2010-07-01

    ..., and Reconstructed Spark Ignition, 4SRB Stationary RICE >500 HP Located at a Major Source of HAP... Limitations for Existing, New, and Reconstructed Spark Ignition, 4SRB Stationary RICE >500 HP Located at a... emission limitations for existing, new and reconstructed 4SRB stationary RICE at 100 percent load plus or...

  15. 40 CFR Table 1b to Subpart Zzzz of... - Operating Limitations for Existing, New, and Reconstructed Spark Ignition, 4SRB Stationary RICE...

    Science.gov (United States)

    2010-07-01

    ..., New, and Reconstructed Spark Ignition, 4SRB Stationary RICE >500 HP Located at a Major Source of HAP... Limitations for Existing, New, and Reconstructed Spark Ignition, 4SRB Stationary RICE >500 HP Located at a... following operating emission limitations for existing, new and reconstructed 4SRB stationary RICE >500 HP...

  16. Estimating sediment discharge: Appendix D

    Science.gov (United States)

    Gray, John R.; Simões, Francisco J. M.

    2008-01-01

    Sediment-discharge measurements usually are available on a discrete or periodic basis. However, estimates of sediment transport often are needed for unmeasured periods, such as when daily or annual sediment-discharge values are sought, or when estimates of transport rates for unmeasured or hypothetical flows are required. Selected methods for estimating suspended-sediment, bed-load, bed- material-load, and total-load discharges have been presented in some detail elsewhere in this volume. The purposes of this contribution are to present some limitations and potential pitfalls associated with obtaining and using the requisite data and equations to estimate sediment discharges and to provide guidance for selecting appropriate estimating equations. Records of sediment discharge are derived from data collected with sufficient frequency to obtain reliable estimates for the computational interval and period. Most sediment- discharge records are computed at daily or annual intervals based on periodically collected data, although some partial records represent discrete or seasonal intervals such as those for flood periods. The method used to calculate sediment- discharge records is dependent on the types and frequency of available data. Records for suspended-sediment discharge computed by methods described by Porterfield (1972) are most prevalent, in part because measurement protocols and computational techniques are well established and because suspended sediment composes the bulk of sediment dis- charges for many rivers. Discharge records for bed load, total load, or in some cases bed-material load plus wash load are less common. Reliable estimation of sediment discharges presupposes that the data on which the estimates are based are comparable and reliable. Unfortunately, data describing a selected characteristic of sediment were not necessarily derived—collected, processed, analyzed, or interpreted—in a consistent manner. For example, bed-load data collected with

  17. Glow discharge in singlet oxygen

    International Nuclear Information System (INIS)

    Vagin, N.P.; Ionin, A.A.; Klimachev, Yu.M.; Sinitsyn, D.V.; Yuryshev, N.N.; Kochetov, I.V.; Napartovich, A.P.

    2003-01-01

    Currently, there is no experimental data on the plasma balance in gas mixtures with a high content of singlet delta oxygen O 2 ( 1 Δ g ). These data can be obtained by studying the parameters of an electric discharge in singlet oxygen produced by a chemical generator. The O 2 ( 1 Δ g ) molecules significantly change the kinetics of electrons and negative ions in plasma. Hence, the discharge conditions at low and high O 2 ( 1 Δ g ) concentrations are very different. Here, the parameters of the positive column of a glow discharge in a gas flow from a chemical singlet-oxygen generator are studied. It is experimentally shown that, at an O 2 ( 1 Δ g ) concentration of 50% and at pressures of 1.5 and 2 torr, the electric field required to sustain the discharge is considerably lower than in the case when all of the oxygen molecules are in the ground state. A theoretical model of the glow discharge is proposed whose predictions are in good agreement with the experimental data

  18. Nonconvulsive status epilepticus associated with periodic lateralized epileptiform discharges in a patient with syphilis

    Directory of Open Access Journals (Sweden)

    Xin Yu

    2016-09-01

    Full Text Available Nonconvulsive status epilepticus (NCSE has been increasingly recognized as a cause of impaired level of consciousness in the ICU and emergency rooms. The confirmation of NCSE is largely based on the EEG, given the nonspecific and pleomorphic clinical manifestations. Debate remains over electroencephalograms (EEG criteria for NCSE. Periodic lateralized epileptiform discharges (PLEDs, have sparked controversy with regard to being part of the ictal vs. interictal spectrum. We report a case of a patient with syphilis who had cognitive decline and damaged consciousness with PLEDs and T2 hyperintensity at temporal and occipital lobe in MRI. After antiepileptic treatment only, his consciousness improved markedly together with the EEG in few days, while the change of MRI was still serious. In this case PLEDs is the sign of NCSE and change of MRI is limbic encephalitis (LE. This report discusses the association of PLEDs and NCSE, and supports the concept of PLEDs as an ictal pattern in some condition.

  19. Compact soft x-ray microscope using a gas-discharge light source.

    Science.gov (United States)

    Benk, Markus; Bergmann, Klaus; Schäfer, David; Wilhein, Thomas

    2008-10-15

    We report on a soft x-ray microscope using a gas-discharge plasma with pseudo spark-like electrode geometry as a light source. The source produces a radiant intensity of 4 x 10(13) photons/(sr pulse) for the 2.88 nm emission line of helium-like nitrogen. At a demonstrated 1 kHz repetition rate a brilliance of 4.3 x 10(9) photons/(microm2 sr s) is obtained for the 2.88 nm line. Ray-tracing simulations show that, employing an adequate grazing incidence collector, a photon flux of 1 x 10(7) photons/(microm2 s) can be achieved with the current source. The applicability of the presented pinch plasma concept to soft x-ray microscopy is demonstrated in a proof-of-principle experiment.

  20. Catalytic aided electrical discharge machining of polycrystalline diamond - parameter analysis of finishing condition

    Science.gov (United States)

    Haikal Ahmad, M. A.; Zulafif Rahim, M.; Fauzi, M. F. Mohd; Abdullah, Aslam; Omar, Z.; Ding, Songlin; Ismail, A. E.; Rasidi Ibrahim, M.

    2018-01-01

    Polycrystalline diamond (PCD) is regarded as among the hardest material in the world. Electrical Discharge Machining (EDM) typically used to machine this material because of its non-contact process nature. This investigation was purposely done to compare the EDM performances of PCD when using normal electrode of copper (Cu) and newly proposed graphitization catalyst electrode of copper nickel (CuNi). Two level full factorial design of experiment with 4 center points technique was used to study the influence of main and interaction effects of the machining parameter namely; pulse-on, pulse-off, sparking current, and electrode materials (categorical factor). The paper shows interesting discovery in which the newly proposed electrode presented positive impact to the machining performance. With the same machining parameters of finishing, CuNi delivered more than 100% better in Ra and MRR than ordinary Cu electrode.

  1. Investigation of partially oxidized Ge and Si nanoparticles produced in repetitive pulsed gas discharge

    Science.gov (United States)

    Mylnikov, D. A.; Lizunova, A. A.; Efimov, A. A.; Ivanov, V. V.

    2017-07-01

    This paper focuses on the properties of nanoparticles obtained in pulsed spark discharge by erosion of silicon and germanium electrodes in inert atmosphere. A distinctive feature of the obtained particles is a small primary particle size of 10-20 nm and a low degree of agglomeration. Due to the small size of the particles and the presence of residual oxygen in a chamber the particles are oxidized. Silicon nanoparticles are oxidized more actively than germanium ones under identical conditions of synthesis. Some of the synthesized nanoparticles are found to have a core-shell structure, a pure semiconductor core and shell of the oxide, which opens wide possibilities for practical use in electronics.

  2. A Laser Spark Plug Ignition System for a Stationary Lean-Burn Natural Gas Reciprocating Engine

    Energy Technology Data Exchange (ETDEWEB)

    McIntyre, D. L. [West Virginia Univ., Morgantown, WV (United States)

    2007-05-01

    To meet the ignition system needs of large bore, high pressure, lean burn, natural gas engines a side pumped, passively Q-switched, Nd:YAG laser was developed and tested. The laser was designed to produce the optical intensities needed to initiate ignition in a lean burn, high compression engine. The laser and associated optics were designed with a passive Q-switch to eliminate the need for high voltage signaling and associated equipment. The laser was diode pumped to eliminate the need for high voltage flash lamps which have poor pumping efficiency. The independent and dependent parameters of the laser were identified and explored in specific combinations that produced consistent robust sparks in laboratory air. Prior research has shown that increasing gas pressure lowers the breakdown threshold for laser initiated ignition. The laser has an overall geometry of 57x57x152 mm with an output beam diameter of approximately 3 mm. The experimentation used a wide range of optical and electrical input parameters that when combined produced ignition in laboratory air. The results show a strong dependence of the output parameters on the output coupler reflectivity, Q-switch initial transmission, and gain media dopant concentration. As these three parameters were lowered the output performance of the laser increased leading to larger more brilliant sparks. The results show peak power levels of up to 3MW and peak focal intensities of up to 560 GW/cm2. Engine testing was performed on a Ricardo Proteus single cylinder research engine. The goal of the engine testing was to show that the test laser performs identically to the commercially available flashlamp pumped actively Q-switched laser used in previous laser ignition testing. The engine testing consisted of a comparison of the in-cylinder, and emissions behavior of the engine using each of the lasers as an ignition system. All engine parameters were kept as constant as possilbe while the equivalence ratio (fueling

  3. Discharge quenching circuit for counters

    International Nuclear Information System (INIS)

    Karasik, A.S.

    1982-01-01

    A circuit for quenching discharges in gas-discharge detectors with working voltage of 3-5 kV based on transistors operating in the avalanche mode is described. The quenching circuit consists of a coordinating emitter follower, amplifier-shaper for avalanche key cascade control which changes potential on the counter electrodes and a shaper of discharge quenching duration. The emitter follower is assembled according to a widely used flowsheet with two transistors. The circuit permits to obtain a rectangular quenching pulse with front of 100 ns and an amplitude of up to 3.2 kV at duration of 500 μm-8 ms. Application of the quenching circuit described permits to obtain countering characteristics with the slope less than or equal to 0.02%/V and plateau extent greater than or equal to 300 V [ru

  4. State Waste Discharge Permit application, 183-N Backwash Discharge Pond

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    As part of the Hanford Federal Facility Agreement and Consent Order negotiations (Ecology et al. 1994), the US Department of Energy, Richland Operations Office, the US Environmental Protection Agency, and the Washington State Department of Ecology agreed that liquid effluent discharges to the ground on the Hanford Site which affect groundwater or have the potential to affect groundwater would be subject to permitting under the structure of Chapter 173--216 (or 173--218 where applicable) of the Washington Administrative Code, the State Waste Discharge Permit Program. As a result of this decision, the Washington State Department of Ecology and the US Department of Energy, Richland Operations Office entered into Consent Order No. DE91NM-177, (Ecology and DOE-RL 1991). The Consent Order No. DE91NM-177 requires a series of permitting activities for liquid effluent discharges. Liquid effluents on the Hanford Site have been classified as Phase I, Phase II, and Miscellaneous Streams. The Consent Order No. DE91NM-177 establishes milestones for State Waste Discharge Permit application submittals for all Phase I and Phase II streams, as well as the following 11 Miscellaneous Streams as identified in Table 4 of the Consent Order No. DE91NM-177.

  5. Small Groups, Big Change: Preliminary Findings from the Sparks for Change Institute

    Science.gov (United States)

    Kirsch, R.; Batchelor, R. L.; Habtes, S. Y.; King, B.; Crockett, J.

    2017-12-01

    The geoscience professoriate continues to under represent women and minorities, yet the value of diversity, both for science as well as recruiting and retaining diverse students, is well known. While there are growing numbers of early career tenure-track minority faculty, low retention rates pose a challenge for sustained diversity in the professoriate. Part of this challenge is the lack of institutional support and recognition in tenure and promotion pathways for faculty who undertake broadening participation efforts. Sparks for Change is a NSF Geoscience Opportunities for Leadership in Diversity (GOLD)-funded project that aims to change departmental culture to better value and reward inclusion and broadening participation efforts. By encouraging, recognizing, and rewarding diversity, equity, and inclusion (DEI) efforts at the department level, we aim to support and retain underrepresented minority (URM) faculty, who often disproportionately undertake these efforts, and to build more inclusive environments for faculty, staff and students alike. Sparks for Change utilizes a small group theory of change, arguing that the effort of a small group of committed individuals inside the organization is the best way to overcome the institutional inertia of academic departments that makes them resistant to change. For this effort, we propose that the ideal composition of these small groups is a junior faculty URM who is interested in DEI in the geosciences, a senior member of that same department who can lend weight to efforts and is positioned to help enact department policy, and an external broadening participation expert who can share best practices and provide accountability for the group. Eleven of these small groups, representing a range of institutions, will be brought together at the Sparks for Change Institute in Boulder, CO, in September. There they will receive leadership training on adaptive, transformative, and solidarity practices, share DEI experiences and

  6. Experimental investigation of the vibrational and thermal response of a laser spark plug

    Science.gov (United States)

    Yoder, Gregory S.

    A study was conducted in order to evaluate the external thermal and vibrational effects on the operation of a laser ignition system for internal combustion (IC) engine applications. West Virginia University (WVU) in conjunction with the National Energy Technology Laboratory (NETL) have constructed a prototype laser spark plug which has been designed to mount directly onto the head of a natural gas engine for the purpose of igniting an air/fuel (A/F) mixture in the engine's combustion chamber. To be considered as a viable replacement for the conventional electrode-based ignition system, integrity, durability and reliability must be justified. Thermal and oscillatory perturbations induced upon the ignition system are major influences that affect laser spark plug (LSP) operation and, therefore, quantifying these effects is necessary to further the advancement and development of this technology. The passively q-switched Nd:YAG laser was mounted on Bruel & Kjaer (B&K) Vibration Exciter Type 4808 Shaker in conjunction with at B&K Power Amplifier Type 2719, which was oscillated in 10 Hz intervals from 0 to 60 Hz using a sine wave to mimic natural gas engine operation. The input signal simulated the rotational velocity of the engine operating from 0 to 3600 RPM with the laser mounted in three different axial orientations. The laser assembly was wrapped with medium-temperature heat tape, outfitted with thermocouples and heated from room temperature to 140 ºF to simulate the temperatures that the LSP may experience when installed on an engine. The acceleration of the payload was varied between 50% and 100% of the oscillator's maximum allowable acceleration in each mounting orientation resulting in a total of 294 total setpoints. For each setpoint, pulse width, pulse width variation, q-switch delay, jitter and output energy were measured and recorded. Each of these dependent variables plays a critical role in multi photon ionization and precise control is necessary to limit

  7. A study of operating parameters on the linear spark ignition engine

    International Nuclear Information System (INIS)

    Lim, Ocktaeck; Hung, Nguyen Ba; Oh, Seokyoung; Kim, Gangchul; Song, Hanho; Iida, Norimasa

    2015-01-01

    Highlights: • An experimental and simulation study of a linear engine is conducted. • The effects of operating parameters on the generating power are investigated. • The air gap length has a significant influence on the generating power. • The generating power of the linear engine is optimized with the value of 111.3 W. • There are no problems for the linear engine after 100 h of durable test. - Abstract: In this paper, we present our experiment and simulation study of a free piston linear engine based on operating conditions and structure of the linear engine for generating electric power. The free piston linear engine includes a two-stroke free piston engine, linear generators, and compressors. In the experimental study, the effects of key parameters such as input caloric value, equivalence ratio, spark timing delay, electrical resistance, and air gap length on the piston dynamics and electric power output are investigated. Propane is used as a fuel in the free piston linear engine, and it is premixed with the air to make a homogeneous charge before go into the cylinder. The air and fuel mass flow rate are varied by a mass flow controller. The experimental results show that the maximum generating power is found with the value of 111 W at the input caloric value of 5.88 kJ/s, spark timing delay of 1.5 ms, equivalence ratio of 1.0, electric resistance of 30 Ω, and air gap length of 1.0 mm. In order to check the durability of the linear engine, a durable test is conducted during 100 h. The experimental results show that there are no problems for the linear engine after about one hundred hours of the durable test. Beside experimental study, a simulation study is conducted to predict operating behavior of the linear engine. In the simulation study, the two-stroke free piston linear engine is modeled and simulated through a combination of three mathematical models including a dynamic model, a linear alternator model and a thermodynamic model. These

  8. 2-Methylfuran: A bio-derived octane booster for spark-ignition engines

    KAUST Repository

    Sarathy, Mani

    2018-04-02

    The efficiency of spark-ignition engines is limited by the phenomenon of knock, which is caused by auto-ignition of the fuel-air mixture ahead of the spark-initiated flame front. The resistance of a fuel to knock is quantified by its octane index; therefore, increasing the octane index of a spark-ignition engine fuel increases the efficiency of the respective engine. However, raising the octane index of gasoline increases the refining costs, as well as the energy consumption during production. The use of alternative fuels with synergistic blending effects presents an attractive option for improving octane index. In this work, the octane enhancing potential of 2-methylfuran (2-MF), a next-generation biofuel, has been examined and compared to other high-octane components (i.e., ethanol and toluene). A primary reference fuel with an octane index of 60 (PRF60) was chosen as the base fuel since it closely represents refinery naphtha streams, which are used as gasoline blend stocks. Initial screening of the fuels was done in an ignition quality tester (IQT). The PRF60/2-MF (80/20 v/v%) blend exhibited longer ignition delay times compared to PRF60/ethanol (80/20 v/v%) blend and PRF60/toluene (80/20 v/v%) blend, even though pure 2-MF is more reactive than both ethanol and toluene. The mixtures were also tested in a cooperative fuels research (CFR) engine under research octane number and motor octane number like conditions. The PRF60/2-MF blend again possesses a higher octane index than other blending components. A detailed chemical kinetic analysis was performed to understand the synergetic blending effect of 2-MF, using a well-validated PRF/2-MF kinetic model. Kinetic analysis revealed superior suppression of low-temperature chemistry with the addition of 2-MF. The results from simulations were further confirmed by homogeneous charge compression ignition engine experiments, which established its superior low-temperature heat release (LTHR) suppression compared to ethanol

  9. Thermoelectric transport properties of polycrystalline titanium diselenide co-intercalated with nickel and titanium using spark plasma sintering

    DEFF Research Database (Denmark)

    Holgate, Tim; Zhu, S.; Zhou, M.

    2013-01-01

    Polycrystalline samples of nickel intercalated (0–5%) TiSe2 were attempted via solid-state reaction in evacuated quartz tubes followed by densification using a spark plasma sintering process. X-ray diffraction data indicated that mixed NiSe2 and TiSe2 phases were present after initial synthesis b...

  10. Spark plasma sintered Sm(2)Co(17)-FeCo nanocomposite permanent magnets synthesized by high energy ball milling.

    Science.gov (United States)

    Sreenivasulu, G; Gopalan, R; Chandrasekaran, V; Markandeyulu, G; Suresh, K G; Murty, B S

    2008-08-20

    Nanocomposite Sm(2)Co(17)-5 wt% FeCo magnets were synthesized by high energy ball milling followed by consolidation into bulk shape by the spark plasma sintering technique. The evolution of magnetic properties was systematically investigated in milled powders as well as in spark plasma sintered samples. A high energy product of 10.2 MGOe and the other magnetic properties of M(s) = 107 emu g(-1), M(r) = 59 emu g(-1), M(r)/M(s) = 0.55 and H(c) = 6.4 kOe were achieved in a 5 h milled and spark plasma sintered Sm(2)Co(17)-5 wt% FeCo nanocomposite magnet. The spark plasma sintering was carried out at 700 °C for 5 min with a pressure of 70 MPa. The nanocomposite showed a higher Curie temperature of 955 °C for the Sm(2)Co(17) phase in comparison to its bulk Curie temperature for the Sm(2)Co(17) phase (920 °C). This higher Curie temperature can improve the performance of the magnet at higher temperatures.

  11. Determination of Cr, Mn, Si, and Ni in carbon steels by optical emission spectrometry with spark source

    International Nuclear Information System (INIS)

    Garcia Gonzalez, M.A.; Pomares Alfonso, M.; Mora Lopez, L.

    1995-01-01

    Elemental composition of steels determines some important of his characteristic moreover it is necessary to obtain their quality certification. Analytical procedure has performed for determination of Cr, Mn, Si and Ni in carbon steels by optical emission spectrometry with spark source. reproducibility of results is 5-11 %. Exactitude has tested with results that have obtained by internationally recognised methods-

  12. Quantitative mapping of zinc fluxes in the mammalian egg reveals the origin of fertilization-induced zinc sparks

    Energy Technology Data Exchange (ETDEWEB)

    Que, Emily L.; Bleher, Reiner; Duncan, Francesca E.; Kong, Betty Y.; Gleber, Sophie C.; Vogt, Stefan; Chen, Si; Garwin, Seth A.; Bayer, Amanda R.; Dravid, Vinayak P.; Woodruff, Teresa K.; O' Halloran, Thomas V.

    2014-12-15

    Fertilization of a mammalian egg initiates a series of 'zinc sparks' that are necessary to induce the egg-to-embryo transition. Despite the importance of these zinc-efflux events little is known about their origin. To understand the molecular mechanism of the zinc spark we combined four physical approaches that resolve zinc distributions in single cells: a chemical probe for dynamic live-cell fluorescence imaging and a combination of scanning transmission electron microscopy with energy-dispersive spectroscopy, X-ray fluorescence microscopy and three-dimensional elemental tomography for high-resolution elemental mapping. We show that the zinc spark arises from a system of thousands of zinc-loaded vesicles, each of which contains, on average, 10(6) zinc atoms. These vesicles undergo dynamic movement during oocyte maturation and exocytosis at the time of fertilization. The discovery of these vesicles and the demonstration that zinc sparks originate from them provides a quantitative framework for understanding how zinc fluxes regulate cellular processes

  13. Quantification of deformation microstructure at ultra-low tensile strain in pure Al prepared by spark plasma sintering

    DEFF Research Database (Denmark)

    Zhang, C. L.; Zhang, Y. B.; Wul, G. L.

    2017-01-01

    A sample of Al with grain size of 5.1 mu m, prepared by spark plasma sintering, was deformed to a nominal strain of 0.35% under exposure to X-ray synchrotron radiation, allowing spatially resolved orientation measurements to be made during loading by use of a micro-diffraction technique. A signif...

  14. High-strength bulk nano-crystalline silver prepared by selective leaching combined with spark plasma sintering

    Czech Academy of Sciences Publication Activity Database

    Marek, I.; Vojtěch, D.; Michalcová, A.; Kubatík, Tomáš František

    2015-01-01

    Roč. 627, March (2015), s. 326-332 ISSN 0921-5093 Institutional support: RVO:61389021 Keywords : Nano-crystalline material * Selective leaching * Silver * Spark plasma sintering * Strength Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 2.647, year: 2015 http://dx.doi.org/10.1016/j.msea.2015.01.014

  15. Fabrication of Ni-Ti Alloy by Self-Propagating High-Temperature Synthesis and Spark Plasma Sintering Technique

    Czech Academy of Sciences Publication Activity Database

    Salvetr, P.; Kubatík, Tomáš František; Pignol, D.; Novák, P.

    2017-01-01

    Roč. 48, č. 2 (2017), s. 772-778 ISSN 1073-5615 Institutional support: RVO:61389021 Keywords : powder metallurgy * Spark plasma sintering Subject RIV: JJ - Other Materials OBOR OECD: Materials engineering Impact factor: 1.642, year: 2016

  16. Spark Plasma Sintering of Dielectric Ceramics Zr0.8Sn0.2TiO4

    Czech Academy of Sciences Publication Activity Database

    Ctibor, P.; Kubatík, Tomáš František; Sedláček, J.; Kotlan, Jiří

    2016-01-01

    Roč. 22, č. 3 (2016), s. 435-439 ISSN 1392-1320 Institutional support: RVO:61389021 Keywords : titanates * dielectric ceramics * spark plasma sintering Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 0.393, year: 2016 http://www.matsc.ktu.lt/index.php/MatSc/article/view/8767

  17. Sparks sädeleb Rabarocki öös. Ettevaatust! Eliidi rünnak. Hu? Hu da hell?

    Index Scriptorium Estoniae

    2007-01-01

    Ameerika ansamblist Sparks. Vaiko Eplik & Eliit heliplaatidest "1: Aastaajad", "2: Aastaajad" ja "3: Kosmoseodüsseia", esinemisest festivalil Rabarock. Hannaliisa Uusma, Leslie Da Bassi ja DJ Criticali projektist HU?, singlitest "Kosmos" ja "Absoluutselt" (Rabarockil esitusel materjal HU? debüütalbumilt "Film")

  18. Basic study of Eu.sup.2+./sup.-doped garnet ceramic scintillator produced by spark plasma sintering

    Czech Academy of Sciences Publication Activity Database

    Sugiyama, K.; Yanagida, T.; Fujimoto, Y.; Yokota, Y.; Ito, A.; Nikl, Martin; Goto, T.; Yoshikawa, A.

    2012-01-01

    Roč. 35, č. 2 (2012), s. 222-226 ISSN 0925-3467 R&D Projects: GA MŠk LH12150 Institutional research plan: CEZ:AV0Z10100521 Keywords : Eu 2+ 5d–4f transition * scintillator * spark plasma sintering Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.918, year: 2012

  19. The total trace element content of some Scottish soils by spark source mass spectrometry

    International Nuclear Information System (INIS)

    Ure, A.M.; Bacon, J.R.; Berrow, M.L.; Watt, J.J.

    1979-01-01

    Quantitative methods of analysis by spark source mass spectrometry have been used to determine the total trace element content of the surface horizons of 10 arable Scottish soils derived from parent materials of different geological origin and used for earlier trace element surveys. Other methods have been used to supplement these analyses for 12 elements including the major elements, and results for a total of 62 elements in the 10 soils are reported. The results are discussed in terms of the geological nature of the soil parent material making use of 62-element soil fingerprints for visual comparison. It is concluded that the total trace element contents of a Scottish soil corresponds to that expected on the basis of the geochemistry of its parent materials and that the influence of agricultural operations on soil contents is of secondary importance. Average soil contents for most elements are closely similar to published values for crustal abundance. (Auth.)

  20. Transparent Yttrium Aluminium Garnet Obtained by Spark Plasma Sintering of Lyophilized Gels

    Directory of Open Access Journals (Sweden)

    M. Suárez

    2009-01-01

    Full Text Available Lyophilized YAG gel, synthesized by the coprecipitation technique, has been sintered to transparency by spark plasma sintering method at 1500∘C. Whereas conventionally dried gels show large agglomerates, over 1 μm, powders from lyophilized gels show no agglomeration with an average particle size below 100 nm. The absence of agglomerates affects on the optical properties of the sintered materials: conventionally dried powders are opaque after sintering, whereas 0.8 mm thick transparent YAG materials with in-line transmittances close to 60% at 680 nm and over 80% in the infrared range have been obtained for the lyophilized gels.