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Sample records for controlled auto ignition

  1. Analysis of cyclic variations during mode switching between spark ignition and controlled auto-ignition combustion operations

    OpenAIRE

    Chen, T; Zhao, H; Xie, H; He, B

    2014-01-01

    © IMechE 2014. Controlled auto-ignition, also known as homogeneous charge compression ignition, has been the subject of extensive research because of their ability to provide simultaneous reductions in fuel consumption and NOx emissions from a gasoline engine. However, due to its limited operation range, switching between controlled auto-ignition and spark ignition combustion is needed to cover the complete operating range of a gasoline engine for passenger car applications. Previous research...

  2. Auto-ignition control in turbocharged internal combustion engines operating with gaseous fuels

    International Nuclear Information System (INIS)

    Duarte, Jorge; Amador, Germán; Garcia, Jesus; Fontalvo, Armando; Vasquez Padilla, Ricardo; Sanjuan, Marco; Gonzalez Quiroga, Arturo

    2014-01-01

    Control strategies for auto-ignition control in turbocharged internal combustion engines operating with gaseous fuels are presented. Ambient temperature and ambient pressure are considered as the disturbing variables. A thermodynamic model for predicting temperature at the ignition point is developed, adjusted and validated with a large experimental data-set from high power turbocharged engines. Based on this model, the performance of feedback and feedforward auto-ignition control strategies is explored. A robustness and fragility analysis for the Feedback control strategies is presented. The feedforward control strategy showed the best performance however its implementation entails adding a sensor and new control logic. The proposed control strategies and the proposed thermodynamic model are useful tools for increasing the range of application of gaseous fuels with low methane number while ensuring a safe running in internal combustion engines. - Highlights: • A model for predicting temperature at the ignition point. • Robust PID, modified PID, and feedforward strategies for auto-ignition control. • λ′ were the best set of tuning equations for calculating controller parameters. • Robust PID showed significant improvements in auto-ignition control. • Feedforward control showed the best performance

  3. Controlled auto-ignition characteristics of methane-air mixture in a rapid intake compression and expansion machine

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Gyubaek; Jeong, Dongsoo [Engine Research Team, Eco-Machinery Research Division, Korea Institute of Machinery and Materials, 104 Sinseongno, Yuseong-gu, Daejeon 305-701 (Korea); Moon, Gunfeel [Department of Clean Environmental system, University of Science and Technology, 52 Eoeun-dong, Yuseong-gu, Daejeon (Korea); Bae, Choongsik [Engine Laboratory, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 373-1 GuSeong-Dong, Yuseong-Gu, Daejeon 305-701 (Korea)

    2010-10-15

    The characteristics of controlled auto-ignition (CAI) were investigated with a methane-air mixture and simulated residual gas, that represents internal exhaust gas recirculation (IEGR). Supply systems were additionally installed on the conventional rapid compression machine (RCM), and this modified machine - a rapid intake compression and expansion machine (RICEM) - was able to simulate an intake stroke for the evaluation of controlled auto-ignition with fuel-air mixture. The fuel-air mixture and the simulated residual gas were introduced separately into the combustion chamber through the spool valves. Various IEGR rates and temperatures of the IEGR gas were tested. The initial reaction and the development in controlled auto-ignition combustion were compared with spark-ignited combustion by visualization with a high-speed digital camera. Under the controlled auto-ignition operation, multi-point ignition and faster combustion were observed. With increasing the temperature of IEGR gas, the auto-ignition timing was advanced and burning duration was shortened. The higher rate of IEGR had the same effects on the combustion of the controlled auto-ignition. However, this trend was reversed with more than 47 per cent of IEGR. (author)

  4. Effects of Mixture Stratification on Combustion and Emissions of Boosted Controlled Auto-Ignition Engines

    Directory of Open Access Journals (Sweden)

    Jacek Hunicz

    2017-12-01

    Full Text Available The stratification of in-cylinder mixtures appears to be an effective method for managing the combustion process in controlled auto-ignition (CAI engines. Stratification can be achieved and controlled using various injection strategies such as split fuel injection and the introduction of a portion of fuel directly before the start of combustion. This study investigates the effect of injection timing and the amount of fuel injected for stratification on the combustion and emissions in CAI engine. The experimental research was performed on a single cylinder engine with direct gasoline injection. CAI combustion was achieved using negative valve overlap and exhaust gas trapping. The experiments were performed at constant engine fueling. Intake boost was applied to control the excess air ratio. The results show that the application of the late injection strategy has a significant effect on the heat release process. In general, the later the injection is and the more fuel is injected for stratification, the earlier the auto-ignition occurs. However, the experimental findings reveal that the effect of stratification on combustion duration is much more complex. Changes in combustion are reflected in NOX emissions. The attainable level of stratification is limited by the excessive emission of unburned hydrocarbons, CO and soot.

  5. Quantitative measurements of in-cylinder gas composition in a controlled auto-ignition combustion engine

    Science.gov (United States)

    Zhao, H.; Zhang, S.

    2008-01-01

    One of the most effective means to achieve controlled auto-ignition (CAI) combustion in a gasoline engine is by the residual gas trapping method. The amount of residual gas and mixture composition have significant effects on the subsequent combustion process and engine emissions. In order to obtain quantitative measurements of in-cylinder residual gas concentration and air/fuel ratio, a spontaneous Raman scattering (SRS) system has been developed recently. The optimized optical SRS setups are presented and discussed. The temperature effect on the SRS measurement is considered and a method has been developed to correct for the overestimated values due to the temperature effect. Simultaneous measurements of O2, H2O, CO2 and fuel were obtained throughout the intake, compression, combustion and expansion strokes. It shows that the SRS can provide valuable data on this process in a CAI combustion engine.

  6. Quantitative measurements of in-cylinder gas composition in a controlled auto-ignition combustion engine

    International Nuclear Information System (INIS)

    Zhao, H; Zhang, S

    2008-01-01

    One of the most effective means to achieve controlled auto-ignition (CAI) combustion in a gasoline engine is by the residual gas trapping method. The amount of residual gas and mixture composition have significant effects on the subsequent combustion process and engine emissions. In order to obtain quantitative measurements of in-cylinder residual gas concentration and air/fuel ratio, a spontaneous Raman scattering (SRS) system has been developed recently. The optimized optical SRS setups are presented and discussed. The temperature effect on the SRS measurement is considered and a method has been developed to correct for the overestimated values due to the temperature effect. Simultaneous measurements of O 2 , H 2 O, CO 2 and fuel were obtained throughout the intake, compression, combustion and expansion strokes. It shows that the SRS can provide valuable data on this process in a CAI combustion engine

  7. Detection of combustion start in the controlled auto ignition engine by wavelet transform of the engine block vibration signal

    International Nuclear Information System (INIS)

    Kim, Seonguk; Min, Kyoungdoug

    2008-01-01

    The CAI (controlled auto ignition) engine ignites fuel and air mixture by trapping high temperature burnt gas using a negative valve overlap. Due to auto ignition in CAI combustion, efficiency improvements and low level NO x emission can be obtained. Meanwhile, the CAI combustion regime is restricted and control parameters are limited. The start of combustion data in the compressed ignition engine are most critical for controlling the overall combustion. In this research, the engine block vibration signal is transformed by the Meyer wavelet to analyze CAI combustion more easily and accurately. Signal acquisition of the engine block vibration is a more suitable method for practical use than measurement of in-cylinder pressure. A new method for detecting combustion start in CAI engines through wavelet transformation of the engine block vibration signal was developed and results indicate that it is accurate enough to analyze the start of combustion. Experimental results show that wavelet transformation of engine block vibration can track the start of combustion in each cycle. From this newly developed method, the start of combustion data in CAI engines can be detected more easily and used as input data for controlling CAI combustion

  8. Detection of combustion start in the controlled auto ignition engine by wavelet transform of the engine block vibration signal

    Science.gov (United States)

    Kim, Seonguk; Min, Kyoungdoug

    2008-08-01

    The CAI (controlled auto ignition) engine ignites fuel and air mixture by trapping high temperature burnt gas using a negative valve overlap. Due to auto ignition in CAI combustion, efficiency improvements and low level NOx emission can be obtained. Meanwhile, the CAI combustion regime is restricted and control parameters are limited. The start of combustion data in the compressed ignition engine are most critical for controlling the overall combustion. In this research, the engine block vibration signal is transformed by the Meyer wavelet to analyze CAI combustion more easily and accurately. Signal acquisition of the engine block vibration is a more suitable method for practical use than measurement of in-cylinder pressure. A new method for detecting combustion start in CAI engines through wavelet transformation of the engine block vibration signal was developed and results indicate that it is accurate enough to analyze the start of combustion. Experimental results show that wavelet transformation of engine block vibration can track the start of combustion in each cycle. From this newly developed method, the start of combustion data in CAI engines can be detected more easily and used as input data for controlling CAI combustion.

  9. Experimental investigation of the influence of internal and external EGR on the combustion characteristics of a controlled auto-ignition two-stroke cycle engine

    International Nuclear Information System (INIS)

    Andwari, Amin Mahmoudzadeh; Aziz, Azhar Abdul; Said, Mohd Farid Muhamad; Latiff, Zulkarnain Abdul

    2014-01-01

    Highlights: • Investigate the effect of In-EGR, Ex-EGR and octane number on a CAI 2-stroke engine. • Effect of In-EGR, Ex-EGR and octane number on combustion phasing of the engine. • Effect of In-EGR, Ex-EGR and octane number on cyclic variability of the engine. • Identify the CAI combustion upper and lower boundary for operating regions. - Abstract: A two-stroke cycle engine incorporated with a controlled auto-ignition combustion approach presents a high thermodynamic efficiency, ultra-low exhaust emissions and high power-to-weight ratio features for future demand of prime movers. The start of auto-ignition, control of the auto-ignition and its cyclic variability, are major concerns that should be addressed in the combustion timing control of controlled auto-ignition engines. Several studies have been performed to examine the effect of internal exhaust gas recirculation utilization on auto-ignited two-stroke cycle engines. However, far too little attention has been devoted to study on the influence of external exhaust gas recirculation on the cyclic variation and the combustion characteristics of controlled auto-ignition two-stroke cycle engines. The purpose of this study is to examine the influence of external exhaust gas recirculation in combination with internal exhaust gas recirculation on the combustion characteristics and the cyclic variability of a controlled auto-ignition two-stroke engine using fuel with different octane numbers. In a detailed experimental investigation, the combustion-related and pressure-related parameters of the engine are examined and statistically associated with the coefficient of variation and the standard deviation. The outcomes of the investigation indicates that the most influential controlled auto-ignition combustion phasing parameters can be managed appropriately via regulating the internal and external exhaust gas recirculation and fuel octane number. In general, start of auto-ignition and its cyclic variability are

  10. Experimental validation of concentration profiles in an HCCI engine, modelled by a multi-component kinetic mechanism: Outline for auto-ignition and emission control

    Energy Technology Data Exchange (ETDEWEB)

    Machrafi, Hatim, E-mail: hatim-machrafi@enscp.f [UPMC Universite Paris 06, Ecole Nationale Superieure de Chimie de Paris, 11, rue de Pierre et Marie Curie, 75005 Paris (France); Universite de Liege, Thermodynamique des Phenomenes Irreversibles, 17, Allee du Six-Aout, 4000 Liege (Belgium)

    2010-10-15

    In order to contribute to the auto-ignition and emission control for Homogeneous Charge Compression Ignition (HCCI), a kinetic multi-component mechanism, containing 62 reactions and 49 species for mixtures of n-heptane, iso-octane and toluene is validated in this work, comparing for the concentration profiles of the fuel, the total hydrocarbons, O{sub 2}, CO{sub 2}, CO, acetaldehyde and iso-butene. These species are sampled during the combustion and quantified. For these measurements an automotive exhaust analyser, a gas chromatograph, coupled to a mass spectrometer and a flame ionisation detector are used, depending on the species to be measured. The fuel, total hydrocarbons, O{sub 2}, CO{sub 2}, iso-butene and acetaldehyde showed a satisfactory quantitative agreement between the mechanism and the experiments. Both the experiments and the modelling results showed the same formation behaviour of the different species. An example is shown of how such a validated mechanism can provide for a set of information of the behaviour of the auto-ignition process and the emission control as a function of engine parameters.

  11. Experimental validation of concentration profiles in an HCCI engine, modelled by a multi-component kinetic mechanism: Outline for auto-ignition and emission control

    International Nuclear Information System (INIS)

    Machrafi, Hatim

    2010-01-01

    In order to contribute to the auto-ignition and emission control for Homogeneous Charge Compression Ignition (HCCI), a kinetic multi-component mechanism, containing 62 reactions and 49 species for mixtures of n-heptane, iso-octane and toluene is validated in this work, comparing for the concentration profiles of the fuel, the total hydrocarbons, O 2 , CO 2 , CO, acetaldehyde and iso-butene. These species are sampled during the combustion and quantified. For these measurements an automotive exhaust analyser, a gas chromatograph, coupled to a mass spectrometer and a flame ionisation detector are used, depending on the species to be measured. The fuel, total hydrocarbons, O 2 , CO 2 , iso-butene and acetaldehyde showed a satisfactory quantitative agreement between the mechanism and the experiments. Both the experiments and the modelling results showed the same formation behaviour of the different species. An example is shown of how such a validated mechanism can provide for a set of information of the behaviour of the auto-ignition process and the emission control as a function of engine parameters.

  12. The possibility of controlled auto-ignition (CAI) in gasoline engine and gas to liquid (GTL) as a fuel of diesel engine in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, D. [Korea Inst. of Machinery and Materials, Daejou (Korea)

    2005-07-01

    A significant challenge grows from the ever-increasing demands for the optimization of performance, emissions, fuel economy and drivability. The most powerful technologies in the near future to improve these factors are believed Controlled Auto-Ignition (CAI) in gasoline engine and Gas to Liquid (GTL) as a fuel of Diesel engine. In recent years there has been an increasing trend to use more complex valvetrain designs from traditional camshaft driven mechanical systems to camless electromagnetic or electrohydraulic solutions. Comparing to fixed valve actuation systems, variable valve actuation (VVA) should be powerful to optimize the engine cycle. The matching of valve events to the engine performance and to emission requirements at a given engine or vehicle operating condition can be further optimized to the Controlled Auto-Ignition (CAI) in gasoline engine, which has benefits in NOx emission, fuel consumption, combustion stability and intake throttle load. In case of Diesel engine, the increasing demands for NOx and soot emission reduction have introduced aftertreatment technologies recently, but been in need of basic solution for the future, such as a super clean fuel like Gas to Liquid (GTL), which has benefits in comparability to diesel fuel, independency from crude oil and reduction of CO, THC and soot emissions. Korea looks to the future with these kinds of technologies, and tries to find the possibility for reaching the future targets in the internal combustion engine. (orig.)

  13. Numerical Analysis of the Interaction between Thermo-Fluid Dynamics and Auto-Ignition Reaction in Spark Ignition Engines

    Science.gov (United States)

    Saijyo, Katsuya; Nishiwaki, Kazuie; Yoshihara, Yoshinobu

    The CFD simulations were performed integrating the low-temperature oxidation reaction. Analyses were made with respect to the first auto-ignition location in the case of a premixed-charge compression auto-ignition in a laminar flow field and in the case of the auto-ignition in an end gas during an S. I. Engine combustion process. In the latter simulation, the spatially-filtered transport equations were solved to express fluctuating temperatures in a turbulent flow in consideration of strong non-linearity to temperature in the reaction equations. It is suggested that the first auto-ignition location does not always occur at higher-temperature locations and that the difference in the locations of the first auto-ignition depends on the time period during which the local end gas temperature passes through the region of shorter ignition delay, including the NTC region.

  14. Intermediate species measurement during iso-butanol auto-ignition

    KAUST Repository

    Ji, Weiqi

    2015-10-01

    © 2015 The Combustion Institute.Published by Elsevier Inc. All rights reserved. This work presents the time histories of intermediate species during the auto-ignition of iso-butanol at high pressure and intermediate temperature conditions obtained using a rapid compression machine and recently developed fast sampling system. Iso-butanol ignition delays were acquired for iso-butanol/O2 mixture with an inert/O2 ratio of 7.26, equivalence ratio of 0.4, in the temperature range of 840-950 K and at pressure of 25 bar. Fast sampling and gas chromatography were used to acquire and quantify the intermediate species during the ignition delay of the same mixture at P = 25.3 bar and T = 905 K. The ignition delay times and quantitative measurements of the mole fraction time histories of methane, ethene, propene, iso-butene, iso-butyraldehyde, iso-butanol, and carbon monoxide were compared with predictions from the detailed mechanisms developed by Sarathy et al., Merchant et al., and Cai et al. It is shown that while the Sarathy mechanism well predicts the overall ignition delay time, it overpredicts ethene by a factor of 6-10, underpredicts iso-butene by a factor of 2, and overpredicts iso-butyraldehyde by a factor of 2. Reaction path and sensitivity analyses were carried out to identify the reactions responsible for the observed inadequacy. The rates of iso-butanol hydrogen atom abstraction by OH radical and the beta-scission reactions of hydroxybutyl radicals were updated based on recently published quantum calculation results. Significant improvements were achieved in predicting ignition delay at high pressures (25 and 30 bar) and the species concentrations of ethene and iso-butene. However, the updated mechanism still overpredicts iso-butyraldehyde concentrations. Also, the updated mechanism degrades the prediction in ignition delay at lower pressure (15 bar) compared to the original mechanism developed by Sarathy et al.

  15. Intermediate species measurement during iso-butanol auto-ignition

    KAUST Repository

    Ji, Weiqi; Zhang, Peng; He, Tanjin; Wang, Zhi; Tao, Ling; He, Xin; Law, Chung K.

    2015-01-01

    © 2015 The Combustion Institute.Published by Elsevier Inc. All rights reserved. This work presents the time histories of intermediate species during the auto-ignition of iso-butanol at high pressure and intermediate temperature conditions obtained using a rapid compression machine and recently developed fast sampling system. Iso-butanol ignition delays were acquired for iso-butanol/O2 mixture with an inert/O2 ratio of 7.26, equivalence ratio of 0.4, in the temperature range of 840-950 K and at pressure of 25 bar. Fast sampling and gas chromatography were used to acquire and quantify the intermediate species during the ignition delay of the same mixture at P = 25.3 bar and T = 905 K. The ignition delay times and quantitative measurements of the mole fraction time histories of methane, ethene, propene, iso-butene, iso-butyraldehyde, iso-butanol, and carbon monoxide were compared with predictions from the detailed mechanisms developed by Sarathy et al., Merchant et al., and Cai et al. It is shown that while the Sarathy mechanism well predicts the overall ignition delay time, it overpredicts ethene by a factor of 6-10, underpredicts iso-butene by a factor of 2, and overpredicts iso-butyraldehyde by a factor of 2. Reaction path and sensitivity analyses were carried out to identify the reactions responsible for the observed inadequacy. The rates of iso-butanol hydrogen atom abstraction by OH radical and the beta-scission reactions of hydroxybutyl radicals were updated based on recently published quantum calculation results. Significant improvements were achieved in predicting ignition delay at high pressures (25 and 30 bar) and the species concentrations of ethene and iso-butene. However, the updated mechanism still overpredicts iso-butyraldehyde concentrations. Also, the updated mechanism degrades the prediction in ignition delay at lower pressure (15 bar) compared to the original mechanism developed by Sarathy et al.

  16. Global reaction mechanism for the auto-ignition of full boiling range gasoline and kerosene fuels

    Science.gov (United States)

    Vandersickel, A.; Wright, Y. M.; Boulouchos, K.

    2013-12-01

    Compact reaction schemes capable of predicting auto-ignition are a prerequisite for the development of strategies to control and optimise homogeneous charge compression ignition (HCCI) engines. In particular for full boiling range fuels exhibiting two stage ignition a tremendous demand exists in the engine development community. The present paper therefore meticulously assesses a previous 7-step reaction scheme developed to predict auto-ignition for four hydrocarbon blends and proposes an important extension of the model constant optimisation procedure, allowing for the model to capture not only ignition delays, but also the evolutions of representative intermediates and heat release rates for a variety of full boiling range fuels. Additionally, an extensive validation of the later evolutions by means of various detailed n-heptane reaction mechanisms from literature has been presented; both for perfectly homogeneous, as well as non-premixed/stratified HCCI conditions. Finally, the models potential to simulate the auto-ignition of various full boiling range fuels is demonstrated by means of experimental shock tube data for six strongly differing fuels, containing e.g. up to 46.7% cyclo-alkanes, 20% napthalenes or complex branched aromatics such as methyl- or ethyl-napthalene. The good predictive capability observed for each of the validation cases as well as the successful parameterisation for each of the six fuels, indicate that the model could, in principle, be applied to any hydrocarbon fuel, providing suitable adjustments to the model parameters are carried out. Combined with the optimisation strategy presented, the model therefore constitutes a major step towards the inclusion of real fuel kinetics into full scale HCCI engine simulations.

  17. Modelling auto ignition of hydrogen in a jet ignition pre-chamber

    Energy Technology Data Exchange (ETDEWEB)

    Boretti, Alberto A. [School of Science and Engineering, University of Ballarat, PO Box 663, Ballarat, Victoria 3353 (Australia)

    2010-04-15

    Spark-less jet ignition pre-chambers are enablers of high efficiencies and load control by quantity of fuel injected when coupled with direct injection of main chamber fuel, thus permitting always lean burn bulk stratified combustion. Towards the end of the compression stroke, a small quantity of hydrogen is injected within the pre-chamber, where it mixes with the air entering from the main chamber. Combustion of the air and fuel mixture then starts within the pre-chamber because of the high temperature of the hot glow plug, and then jets of partially combusted hot gases enter the main chamber igniting there in the bulk, over multiple ignition points, lean stratified mixtures of air and fuel. The paper describes the operation of the spark-less jet ignition pre-chamber coupling CFD and CAE engine simulations to allow component selection and engine performance evaluation. (author)

  18. Optimum injection and combustion for gaseous fuel engine : characteristics of hydrogen auto-ignition phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Tsujimura, T.; Mikami, S.; Senda, J.; Fujimoto, H. [Doshisha Univ. (Japan). Dept. of Mechanical Engineering; Nakatani, K. [Fuji Heavy Industries Ltd. (Japan); Tokunaga, Y. [Kawasaki Heavy Industries Ltd. (Japan)

    2002-07-01

    A study was conducted in which the auto-ignition characteristics of hydrogen were examined in order to determine which factors dominate auto-ignition delay of hydrogen jets. Experiments were performed in a rapid compression/expansion machine in order to study the effects of ambient gas density and oxygen concentration on the auto-ignition delays. The focus of research was on an inert gas circulation type cogeneration system to apply hydrogen to a medium-sized diesel engine. Freedom of fuel-oxidizer mixing, ignition and combustion in the system could be achieved for stable combustion, high thermal efficiency, and zero emission. The study also involved chemical analysis using a detailed hydrogen reaction model that could simulate auto-ignition delays under various temperature, pressures, equivalence ratio, and dilution. It is shown that auto-ignition delays of hydrogen jets are very dependent on the ambient gas temperature and less dependent on its density and oxygen concentration. Temperature and hydrogen concentrations have significant impacts on the production and consumption rates of H{sub 2}O{sub 2} and OH radicals. 21 refs., 1 tab., 10 figs.

  19. Auto-ignition generated combustion. Pt. 2. Thermodynamic fundamentals; Verbrennungssteuerung durch Selbstzuendung. T. 2. Experimentelle Analyse

    Energy Technology Data Exchange (ETDEWEB)

    Guibert, P. [Paris-6 Univ. (France). Lab. de Mecanique Physique; Morin, C. [Paris-6 Univ. (France); Mokhtari, S.

    2004-02-01

    The combustion initiation by auto-ignition demonstrates benefits in NO{sub x} reduction and in process stability for both spark-ignited and compression ignited engines. Based on the better thermodynamic particularities of the auto-ignition, which have been presented in the first part, the characteristics of this process are demonstrated in the second part by experimental analysis. For comparison with similar studies, the analyses have been carried out in base of a two stroke loop scavenged spark-ignition single cylinder engine. (orig.) [German] Die Steuerung der Verbrennung durch Selbstzuendung zeigt Vorteile bezueglich Senkung der NO{sub x}-Emission und Prozessstabilitaet, sowohl bei Otto- als auch bei Dieselmotoren. Auf Grundlage der thermodynamischen Besonderheiten der Selbstzuendvorgaenge, die im ersten Teil praesentiert wurden, erfolgt im zweiten Teil eine experimentelle Betrachtung der Prozesscharakteristika. Zur Vergleichbarkeit mit aehnlichen Untersuchungen wird die experimentelle Analyse auf Basis eines Zweitakt-Einzylinder-Ottomotors mit Umkehrspuelung durchgefuehrt. (orig.)

  20. Experimental investigation of the auto-ignition characteristics of oxygenated reference fuel compounds

    Science.gov (United States)

    Walton, Stephen Michael

    intermediates measured during methyl butanoate ignition indicated that pathways leading to the formation of small hydrocarbons are relatively well represented in the reaction mechanism. The results of this work provide archival benchmark data for improved understanding of the dominant reaction pathways and species controlling the auto-ignition of oxygenated reference fuel compounds. These data also provide a path for continued development of chemical kinetic models to optimize practical combustion systems.

  1. The influence of different auto-ignition modes on the behavior of pressure waves

    International Nuclear Information System (INIS)

    Xu, Han; Yao, Anren; Yao, Chunde

    2015-01-01

    Highlights: • Modes of pressure oscillations in knocking, HCCI and super knock are recognized. • Three representative auto-ignition modes in engines are proposed. • A new method of “Energy Injected” is brought into understanding pressure wave. • Simulation results revealed the decisive factors for these three auto-ignition modes. • Different modes lead to different pressure wave behaviors damaging engines. - Abstract: For internal combustion engines, the knock of Homogeneous Charge Compression Ignition engines, the conventional knock of gasoline engines and the super knock are all caused by the auto-ignition of unburned mixture which leads to the oscillation burning, but their Maximal Pressure Oscillation Amplitude (MPOA) and Maximum Pressure Rising Rate (MPRR) are totally different. In order to explore the reason, we propose three typical auto-ignition modes and then bring up the method of “Energy Injected” (EI) which is based on the experiment measured heat release rate. Through changing the heat source term in the energy equation for different auto-ignition modes, we conducted a series of numerical simulations for these three modes. After that, the following pressure oscillations can be compared and analyzed. The numerical simulation results show that different combustion pressure waves with different oscillation characteristics come from different auto-ignition modes, thus the macroscopic MPRR and MPOA are totally different. Furthermore, the method of “EI” based on the experiment measured heat release rate can accurately and rapidly help to research the formation and propagation of pressure waves in the engine combustion chamber.

  2. Effects of methyl substitution on the auto-ignition of C16 alkanes

    KAUST Repository

    Lapuerta, Magín

    2015-12-18

    The auto-ignition quality of diesel fuels, quantified by their cetane number or derived cetane number (DCN), is a critical design property to consider when producing and upgrading synthetic paraffinic fuels. It is well known that auto-ignition characteristics of paraffinic fuels depend on their degree of methyl substitution. However, there remains a need to study the governing chemical functionalities contributing to such ignition characteristics, especially in the case of methyl substitutions, which have not been studied in detail. In this work, the auto-ignition of 2,6,10-trimethyltridecane has been compared with the reference hydrocarbons used for cetane number determination, i.e. n-hexadecane and heptamethylnonane, all of them being C16 isomers. Results from a constant-volume combustion chamber under different pressure and temperature initial conditions showed that the ignition delay time for both cool flame and main combustion events increased less from n-hexadecane to trimethyltridecane than from trimethyltridecane to heptamethylnonane. Additional experimental results from blends of these hydrocarbons, together with kinetic modelling, showed that auto-ignition times and combustion rates were correlated to the concentration of the functional groups indicative of methyl substitution, although not in a linear manner. When the concentration of these functional groups decreased, the first stage OH radical concentration increased and ignition delay times decreased, whereas when their concentration increased, H2O2 production was slower and ignition was retarded. Contrary to the ignition delay times, DCN was correlated linearly with functional groups, thus homogenizing the range of values and clarifying the differences between fuels.

  3. Effects of methyl substitution on the auto-ignition of C16 alkanes

    KAUST Repository

    Lapuerta, Magí n; Herná ndez, Juan J.; Sarathy, Mani

    2015-01-01

    The auto-ignition quality of diesel fuels, quantified by their cetane number or derived cetane number (DCN), is a critical design property to consider when producing and upgrading synthetic paraffinic fuels. It is well known that auto-ignition characteristics of paraffinic fuels depend on their degree of methyl substitution. However, there remains a need to study the governing chemical functionalities contributing to such ignition characteristics, especially in the case of methyl substitutions, which have not been studied in detail. In this work, the auto-ignition of 2,6,10-trimethyltridecane has been compared with the reference hydrocarbons used for cetane number determination, i.e. n-hexadecane and heptamethylnonane, all of them being C16 isomers. Results from a constant-volume combustion chamber under different pressure and temperature initial conditions showed that the ignition delay time for both cool flame and main combustion events increased less from n-hexadecane to trimethyltridecane than from trimethyltridecane to heptamethylnonane. Additional experimental results from blends of these hydrocarbons, together with kinetic modelling, showed that auto-ignition times and combustion rates were correlated to the concentration of the functional groups indicative of methyl substitution, although not in a linear manner. When the concentration of these functional groups decreased, the first stage OH radical concentration increased and ignition delay times decreased, whereas when their concentration increased, H2O2 production was slower and ignition was retarded. Contrary to the ignition delay times, DCN was correlated linearly with functional groups, thus homogenizing the range of values and clarifying the differences between fuels.

  4. Safety characteristics of hydrogen at super ambient conditions: lubricant contamination influencing the auto ignition temperature

    International Nuclear Information System (INIS)

    Liebner, C.; Schroder, V.; Holtappels, K.

    2006-01-01

    Inventing hydrogen as a commonly used future energy carrier the long term social acceptance as well as the clean energy image strongly depends upon the safety of its applications. The safety characteristics of hydrogen build a special challenge e.g. in the field of combustion engine development. Small impurities from lubricants used in motors and pumps, may serve as radical source, strongly influencing the auto ignition temperature of hydrogen. Auto Ignition Temperature (AIT) of Hydrogen-Air mixtures were measured in closed autoclaves made from stainless steel, similar to the closed bomb method described in the European standard EN 1839. Initial pressures of 10 bar(a) and 30 bar(a) of a premixed stoichiometric hydrogen-air mixture were investigated. Auto ignition can be obtained about 100 K below the standard AIT (560 deg C, atmospheric pressure) and 300 K below the standard AIT when contaminated through motor oil. (authors)

  5. Performance Characterization and Auto-Ignition Performance of a Rapid Compression Machine

    Directory of Open Access Journals (Sweden)

    Hao Liu

    2014-09-01

    Full Text Available A rapid compression machine (RCM test bench is developed in this study. The performance characterization and auto-ignition performance tests are conducted at an initial temperature of 293 K, a compression ratio of 9.5 to 16.5, a compressed temperature of 650 K to 850 K, a driving gas pressure range of 0.25 MPa to 0.7 MPa, an initial pressure of 0.04 MPa to 0.09 MPa, and a nitrogen dilution ratio of 35% to 65%. A new type of hydraulic piston is used to address the problem in which the hydraulic buffer adversely affects the rapid compression process. Auto-ignition performance tests of the RCM are then performed using a DME–O2–N2 mixture. The two-stage ignition delay and negative temperature coefficient (NTC behavior of the mixture are observed. The effects of driving gas pressure, compression ratio, initial pressure, and nitrogen dilution ratio on the two-stage ignition delay are investigated. Results show that both the first-stage and overall ignition delays tend to increase with increasing driving gas pressure. The driving gas pressure within a certain range does not significantly influence the compressed pressure. With increasing compression ratio, the first-stage ignition delay is shortened, whereas the second-stage ignition delay is extended. With increasing initial pressure, both the first-stage and second-stage ignition delays are shortened. The second-stage ignition delay is shortened to a greater extent than that of the first-stage. With increasing nitrogen dilution ratio, the first-stage ignition delay is shortened, whereas the second-stage is extended. Thus, overall ignition delay presents different trends under various compression ratios and compressed pressure conditions.

  6. A free-boundary value problem related to auto ignition of ...

    African Journals Online (AJOL)

    We examine a free boundary value problem related to auto ignition of combustible fluid in insulation materials. The criteria for the existence of similarity solution of the model equations are established. The conditions for the existence of unique solution are also stated. The numerical results which show the influence of ...

  7. Influence of fuel type, dilution and equivalence ratio on the emission reduction from the auto-ignition in an Homogeneous Charge Compression Ignition engine

    Energy Technology Data Exchange (ETDEWEB)

    Machrafi, Hatim [UPMC Universite Paris 06, ENSCP, 11 rue de Pierre et Marie Curie, 75005 Paris (France); UPMC Universite Paris 06, Institut Jean Le Rond D' Alembert, 4 place Jussieu, 75252 Paris cedex 05 (France); Universite Libre de Bruxelles, TIPs - Fluid Physics, CP165/67, 50 Avenue F.D. Roosevelt, 1050 Brussels (Belgium); Cavadias, Simeon [UPMC Universite Paris 06, ENSCP, 11 rue de Pierre et Marie Curie, 75005 Paris (France); UPMC Universite Paris 06, Institut Jean Le Rond D' Alembert, 4 place Jussieu, 75252 Paris cedex 05 (France); Amouroux, Jacques [UPMC Universite Paris 06, ENSCP, 11 rue de Pierre et Marie Curie, 75005 Paris (France)

    2010-04-15

    One technology that seems to be promising for automobile pollution reduction is the Homogeneous Charge Compression Ignition (HCCI). This technology still faces auto-ignition and emission-control problems. This paper focuses on the emission problem, since it is incumbent to realize engines that pollute less. For this purpose, this paper presents results concerning the measurement of the emissions of CO, NO{sub x}, CO{sub 2}, O{sub 2} and hydrocarbons. HCCI conditions are used, with equivalence ratios between 0.26 and 0.54, inlet temperatures of 70 C and 120 C and compression ratios of 10.2 and 13.5, with different fuel types: gasoline, gasoline surrogate, diesel, diesel surrogate and mixtures of n-heptane/toluene. The effect of dilution is considered for gasoline, while the effect of the equivalence ratio is considered for all the fuels. No significant amount of NO{sub x} has been measured. It appeared that the CO, O{sub 2} and hydrocarbon emissions were reduced by decreasing the toluene content of the fuel and by decreasing the dilution. The opposite holds for CO{sub 2}. The reduction of the hydrocarbon emission appears to compete with the reduction of the CO{sub 2} emission. Diesel seemed to produce less CO and hydrocarbons than gasoline when auto-ignited. An example of emission reduction control is presented in this paper. (author)

  8. Impact of Formaldehyde Addition on Auto-Ignition in Internal-Combustion Engines

    Science.gov (United States)

    Kuwahara, Kazunari; Ando, Hiromitsu; Furutani, Masahiro; Ohta, Yasuhiko

    By employing a direct-injection diesel engine equipped with a common-rail type of injection system, by adding formaldehyde (CH2O) to the intake air, and by changing the fuel-injection timing, the compression ratio and the intake-air temperature, a mechanism for CH2O as a fuel additive to affect auto-ignition was discussed. Unlike an HCCI type of engine, the diesel engine can expose an air-fuel mixture only to a limited range of the in-cylinder temperature before the ignition, and can separate low- and high-temperature parts of the mechanism. When low-temperature oxidation starts at a temperature above 900K, there are cases that the CH2O advances the ignition timing. Below 900K, to the contrary, it always retards the timing. It is because, above 900K, a part of the CH2O changes into CO together with H2O2 as an ignition promoter. Below 900K, on the other hand, the CH2O itself acts as an OH radical scavenger against cool-flame reaction, from the beginning of low-temperature oxidation. Then, the engine was modified for its extraordinary function as a gasoline-knocking generator, in order that an effect of CH2O on knocking could be discussed. The CH2O retards the onset of auto-ignition of an end gas. Judging from a large degree of the retardation, the ignition is probably triggered below 900K.

  9. Predicting auto-ignition characteristics of RCCI combustion using a multi-zone model

    NARCIS (Netherlands)

    Egüz, U.; Maes, N.C.J.; Leermakers, C.A.J.; Somers, L.M.T.; Goey, de L.P.H.

    2013-01-01

    The objective of new combustion concepts is to meet emission standards by improving fuel air mixing prior to ignition. Since there is no overlap between injection and ignition, combustion is governed mainly by chemical kinetics and it is challenging to control the phasing of ignition. Reactivity

  10. Auto-Ignition and Spray Characteristics of n-Heptane and iso-Octane Fuels in Ignition Quality Tester

    KAUST Repository

    Jaasim, Mohammed; Elhagrasy, Ayman; Sarathy, Mani; Chung, Suk-Ho; Im, Hong G.

    2018-01-01

    breakup models, namely the Kelvin-Helmholtz/Rayleigh-Taylor (KH-RT) and linearized instability sheet atomization (LISA) models, in terms of their influence on auto-ignition predictions. Two spray models resulted in different local mixing

  11. External heating of electrical cables and auto-ignition investigation

    Energy Technology Data Exchange (ETDEWEB)

    Courty, L., E-mail: leo.courty@univ-orleans.fr [Univ. Orleans, PRISME EA 4229, 63 Avenue de Lattre de Tassigny, 18020 Bourges (France); Garo, J.P. [Institut P’, UPR 3346 CNRS, ENSMA, Univ. Poitiers, 1 Av. Clément Ader, Téléport 2, BP 40109, 86961 Futuroscope Chasseneuil (France)

    2017-01-05

    Highlights: • Electrical cables pyrolysis and flammability have been studied. • Two different experimental setups were used to study cables mass loss and flammability. • A 1-D thermal model for cables mass loss and temperature is proposed. • Spontaneous and piloted ignitions have been investigated. - Abstract: Electric cables are now extensively used for both residential and industrial applications. During more than twenty years, multi-scale approaches have been developed to study fire behavior of such cables that represents a serious challenge. Cables are rather complicated materials because they consist of an insulated part and jacket of polymeric materials. These polymeric materials can have various chemical structures, thicknesses and additives and generally have a char-forming tendency when exposed to heat source. In this work, two test methods are used for the characterization of cable pyrolysis and flammability. The first one permits the investigation of cable pyrolysis. A description of the cable mass loss is obtained, coupling an Arrhenius expression with a 1D thermal model of cables heating. Numerical results are successfully compared with experimental data obtained for two types of cable commonly used in French nuclear power plants. The second one is devoted to ignition investigations (spontaneous or piloted) of these cables. All these basic observations, measurements and modelling efforts are of major interest for a more comprehensive fire resistance evaluation of electric cables.

  12. External heating of electrical cables and auto-ignition investigation

    International Nuclear Information System (INIS)

    Courty, L.; Garo, J.P.

    2017-01-01

    Highlights: • Electrical cables pyrolysis and flammability have been studied. • Two different experimental setups were used to study cables mass loss and flammability. • A 1-D thermal model for cables mass loss and temperature is proposed. • Spontaneous and piloted ignitions have been investigated. - Abstract: Electric cables are now extensively used for both residential and industrial applications. During more than twenty years, multi-scale approaches have been developed to study fire behavior of such cables that represents a serious challenge. Cables are rather complicated materials because they consist of an insulated part and jacket of polymeric materials. These polymeric materials can have various chemical structures, thicknesses and additives and generally have a char-forming tendency when exposed to heat source. In this work, two test methods are used for the characterization of cable pyrolysis and flammability. The first one permits the investigation of cable pyrolysis. A description of the cable mass loss is obtained, coupling an Arrhenius expression with a 1D thermal model of cables heating. Numerical results are successfully compared with experimental data obtained for two types of cable commonly used in French nuclear power plants. The second one is devoted to ignition investigations (spontaneous or piloted) of these cables. All these basic observations, measurements and modelling efforts are of major interest for a more comprehensive fire resistance evaluation of electric cables.

  13. A numerical study of the influence of ammonia addition on the auto-ignition limits of methane/air mixtures

    International Nuclear Information System (INIS)

    Van den Schoor, F.; Norman, F.; Vandebroek, L.; Verplaetsen, F.; Berghmans, J.

    2009-01-01

    In this study the auto-ignition limit of ammonia/methane/air mixtures is calculated based upon a perfectly stirred reactor model with convective heat transfer. The results of four different reaction mechanisms are compared with existing experimental data at an initial temperature of 723 K with ammonia concentrations of 0-20 mol.% and methane concentrations of 2.5-10 mol.%. It is found that the calculation of the auto-ignition limit pressure at constant temperature leads to larger relative deviations between calculated and experimental results than the calculation of the auto-ignition temperature at constant pressure. In addition to the calculations, a reaction path analysis is performed to explain the observed lowering of the auto-ignition limit of methane/air mixtures by ammonia addition. It is found that this decrease is caused by the formation of NO and NO 2 , which enhance the oxidation of methane at low temperatures.

  14. Effect of oxygen content on n-heptane auto-ignition characteristics in a HCCI engine

    International Nuclear Information System (INIS)

    Wu, Zhijun; Kang, Zhe; Deng, Jun; Hu, Zongjie; Li, Liguang

    2016-01-01

    Highlights: • n-Heptane HCCI combustion under air and oxygen intake was compared. • n-Heptane auto-ignition postponed due to higher specific heat capacity as oxygen increase. • The increment of heat release fraction during low temperature reaction is studied. • Oxygen enrichment lead to suppressed negative temperature coefficient. • The mechanism of low temperature reaction enhancement as oxygen increase is investigated. - Abstract: To take maximum advantage of the high efficiency of homogeneous charge compression ignition combustion mode and internal combustion Rankine cycle concept, in this study, the n-heptane auto-ignition characteristics have been investigated using a compression ignition internal combustion Rankine cycle engine test bench and a zero-dimensional thermodynamic model coupled with a detailed kinetic model. The n-heptane auto-ignition process shows that under both air and oxygen intake, a typical two-stage combustion in which oxygen enrichment has very minor effects on the n-heptane high temperature reaction. The higher specific heat capacity of oxygen compared with nitrogen leads to an overall increased specific heat capacity, which lowers the in-cylinder temperature during compression stroke, thereby delaying the low temperature reaction initial timing. The higher oxygen content also improves the H-atom abstraction, first O_2 addition, second O_2 addition and peroxyalkylhydroperoxide isomerization, thereby improving the overall reaction rate and the heat release fraction of low temperature reaction. As a result, the in-cylinder temperature at the end of low temperature reaction also increases, thereby shortening significantly the negative temperature coefficient duration compared with a combustion cycle using air as oxidizer.

  15. External heating of electrical cables and auto-ignition investigation.

    Science.gov (United States)

    Courty, L; Garo, J P

    2017-01-05

    Electric cables are now extensively used for both residential and industrial applications. During more than twenty years, multi-scale approaches have been developed to study fire behavior of such cables that represents a serious challenge. Cables are rather complicated materials because they consist of an insulated part and jacket of polymeric materials. These polymeric materials can have various chemical structures, thicknesses and additives and generally have a char-forming tendency when exposed to heat source. In this work, two test methods are used for the characterization of cable pyrolysis and flammability. The first one permits the investigation of cable pyrolysis. A description of the cable mass loss is obtained, coupling an Arrhenius expression with a 1D thermal model of cables heating. Numerical results are successfully compared with experimental data obtained for two types of cable commonly used in French nuclear power plants. The second one is devoted to ignition investigations (spontaneous or piloted) of these cables. All these basic observations, measurements and modelling efforts are of major interest for a more comprehensive fire resistance evaluation of electric cables. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Characteristics of Syngas Auto-ignition at High Pressure and Low Temperature Conditions with Thermal Inhomogeneities

    KAUST Repository

    Pal, Pinaki; Mansfield, Andrew B.; Wooldridge, Margaret S.; Im, Hong G.

    2015-01-01

    Effects of thermal inhomogeneities on syngas auto-ignition at high-pressure low-temperature conditions, relevant to gas turbine operation, are investigated using detailed one-dimensional numerical simulations. Parametric tests are carried out for a range of thermodynamic conditions (T = 890-1100 K, P = 3-20 atm) and composition (Ф = 0.1, 0.5). Effects of global thermal gradients and localized thermal hot spots are studied. In the presence of a thermal gradient, the propagating reaction front transitions from spontaneous ignition to deflagration mode as the initial mean temperature decreases. The critical mean temperature separating the two distinct auto-ignition modes is computed using a predictive criterion and found to be consistent with front speed and Damkohler number analyses. The hot spot study reveals that compression heating of end-gas mixture by the propagating front is more pronounced at lower mean temperatures, significantly advancing the ignition delay. Moreover, the compression heating effect is dependent on the domain size.

  17. Characteristics of Syngas Auto-ignition at High Pressure and Low Temperature Conditions with Thermal Inhomogeneities

    KAUST Repository

    Pal, Pinaki

    2015-05-31

    Effects of thermal inhomogeneities on syngas auto-ignition at high-pressure low-temperature conditions, relevant to gas turbine operation, are investigated using detailed one-dimensional numerical simulations. Parametric tests are carried out for a range of thermodynamic conditions (T = 890-1100 K, P = 3-20 atm) and composition (Ф = 0.1, 0.5). Effects of global thermal gradients and localized thermal hot spots are studied. In the presence of a thermal gradient, the propagating reaction front transitions from spontaneous ignition to deflagration mode as the initial mean temperature decreases. The critical mean temperature separating the two distinct auto-ignition modes is computed using a predictive criterion and found to be consistent with front speed and Damkohler number analyses. The hot spot study reveals that compression heating of end-gas mixture by the propagating front is more pronounced at lower mean temperatures, significantly advancing the ignition delay. Moreover, the compression heating effect is dependent on the domain size.

  18. Auto-Ignition and Spray Characteristics of n-Heptane and iso-Octane Fuels in Ignition Quality Tester

    KAUST Repository

    Jaasim, Mohammed

    2018-04-04

    Numerical simulations were conducted to systematically assess the effects of different spray models on the ignition delay predictions and compared with experimental measurements obtained at the KAUST ignition quality tester (IQT) facility. The influence of physical properties and chemical kinetics over the ignition delay time is also investigated. The IQT experiments provided the pressure traces as the main observables, which are not sufficient to obtain a detailed understanding of physical (breakup, evaporation) and chemical (reactivity) processes associated with auto-ignition. A three-dimensional computational fluid dynamics (CFD) code, CONVERGE™, was used to capture the detailed fluid/spray dynamics and chemical characteristics within the IQT configuration. The Reynolds-averaged Navier-Stokes (RANS) turbulence with multi-zone chemistry sub-models was adopted with a reduced chemical kinetic mechanism for n-heptane and iso-octane. The emphasis was on the assessment of two common spray breakup models, namely the Kelvin-Helmholtz/Rayleigh-Taylor (KH-RT) and linearized instability sheet atomization (LISA) models, in terms of their influence on auto-ignition predictions. Two spray models resulted in different local mixing, and their influence in the prediction of auto-ignition was investigated. The relative importance of physical ignition delay, characterized by spray evaporation and mixing processes, in the overall ignition behavior for the two different fuels were examined. The results provided an improved understanding of the essential contribution of physical and chemical processes that are critical in describing the IQT auto-ignition event at different pressure and temperature conditions, and allowed a systematic way to distinguish between the physical and chemical ignition delay times.

  19. An experimental and numerical analysis of the HCCI auto-ignition process of primary reference fuels, toluene reference fuels and diesel fuel in an engine, varying the engine parameters

    Energy Technology Data Exchange (ETDEWEB)

    Machrafi, Hatim; Cavadias, Simeon [UPMC Universite Paris 06, LGPPTS, Ecole Nationale Superieure de Chimie de Paris, 11, rue de Pierre et Marie Curie, 75005 Paris (France); UPMC Universite Paris 06, Institut Jean Le Rond D' Alembert, 2, place de la Gare de Ceinture, 78210 St Cyr-I' Ecole (France); Gilbert, Philippe [UPMC Universite Paris 06, Institut Jean Le Rond D' Alembert, 2, place de la Gare de Ceinture, 78210 St Cyr-I' Ecole (France)

    2008-11-15

    For a future HCCI engine to operate under conditions that adhere to environmental restrictions, reducing fuel consumption and maintaining or increasing at the same time the engine efficiency, the choice of the fuel is crucial. For this purpose, this paper presents an auto-ignition investigation concerning the primary reference fuels, toluene reference fuels and diesel fuel, in order to study the effect of linear alkanes, branched alkanes and aromatics on the auto-ignition. The auto-ignition of these fuels has been studied at inlet temperatures from 25 to 120 C, at equivalence ratios from 0.18 to 0.53 and at compression ratios from 6 to 13.5, in order to extend the range of investigation and to assess the usability of these parameters to control the auto-ignition. It appeared that both iso-octane and toluene delayed the ignition with respect to n-heptane, while toluene has the strongest effect. This means that aromatics have higher inhibiting effects than branched alkanes. In an increasing order, the inlet temperature, equivalence ratio and compression ratio had a promoting effect on the ignition delays. A previously experimentally validated reduced surrogate mechanism, for mixtures of n-heptane, iso-octane and toluene, has been used to explain observations of the auto-ignition process. (author)

  20. Auto-ignition modelling: analysis of the dilution effects by the unburnt gases and of the interactions with turbulence for diesel homogeneous charge compression ignition (HCCI) engines; Modelisation de l'auto-inflammation: analyse des effets de la dilution par les gaz brules et des interactions avec la turbulence dediee aux moteurs Diesel a charge homogene

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, G.

    2005-09-15

    Homogeneous Charge Compression Ignition (HCCI) is an alternative engine combustion process that offers the potential for substantial reductions in both NO{sub x} and particulate matter still providing high Diesel-like efficiencies. Combustion in HCCI mode takes place essentially by auto-ignition. It is mainly controlled by the chemical kinetics. It is therefore necessary to introduce detailed chemistry effects in combustion CFD codes in order to properly model the HCCI combustion process. The objective of this work is to develop an auto-ignition model including detailed chemical kinetics and its interactions with turbulence. Also, a comprehensive study has been performed to analyze the chemical influence of CO and H{sub 2} residual species on auto-ignition, which can be present in the exhaust gases. A new auto-ignition model, TKI-PDF (Tabulated Kinetics for Ignition - with turbulent mixing interactions through a pdf approach) dedicated to RANS 3D engine combustion CFD calculations is proposed. The TKI-PDF model is formulated in order to accommodate the detailed chemical kinetics of auto-ignition coupled with turbulence/chemistry interactions. The complete model development and its validation against experimental results are presented in two parts. The first part of this work describes the detailed chemistry input to the model. The second part is dedicated to the turbulent mixing description. A method based on a progress variable reaction rate tabulation is used. A look-up table for the progress variable reaction rates has been built through constant volume complex chemistry simulations. Instantaneous local reaction rates inside the CFD computational cell are then calculated by linear interpolation inside the look-up table depending on the local thermodynamic conditions. In order to introduce the turbulent mixing effects on auto-ignition, a presumed pdf approach is used. The model has been validated in different levels. First, the detailed kinetic approach was

  1. Auto-ignitions of a methane/air mixture at high and intermediate temperatures

    Science.gov (United States)

    Leschevich, V. V.; Martynenko, V. V.; Penyazkov, O. G.; Sevrouk, K. L.; Shabunya, S. I.

    2016-09-01

    A rapid compression machine (RCM) and a shock tube (ST) have been employed to study ignition delay times of homogeneous methane/air mixtures at intermediate-to-high temperatures. Both facilities allow measurements to be made at temperatures of 900-2000 K, at pressures of 0.38-2.23 MPa, and at equivalence ratios of 0.5, 1.0, and 2.0. In ST experiments, nitrogen served as a diluent gas, whereas in RCM runs the diluent gas composition ranged from pure nitrogen to pure argon. Recording pressure, UV, and visible emissions identified the evolution of chemical reactions. Correlations of ignition delay time were generated from the data for each facility. At temperatures below 1300 K, a significant reduction of average activation energy from 53 to 15.3 kcal/mol was obtained. Moreover, the RCM data showed significant scatter that dramatically increased with decreasing temperature. An explanation for the abnormal scatter in the data was proposed based on the high-speed visualization of auto-ignition phenomena and experiments performed with oxygen-free and fuel-free mixtures. It is proposed that the main reason for such a significant reduction of average activation energy is attributable to the premature ignition of ultrafine particles in the reactive mixture.

  2. Performance Characterization and Auto-Ignition Performance of a Rapid Compression Machine

    OpenAIRE

    Hao Liu; Hongguang Zhang; Zhicheng Shi; Haitao Lu; Guangyao Zhao; Baofeng Yao

    2014-01-01

    A rapid compression machine (RCM) test bench is developed in this study. The performance characterization and auto-ignition performance tests are conducted at an initial temperature of 293 K, a compression ratio of 9.5 to 16.5, a compressed temperature of 650 K to 850 K, a driving gas pressure range of 0.25 MPa to 0.7 MPa, an initial pressure of 0.04 MPa to 0.09 MPa, and a nitrogen dilution ratio of 35% to 65%. A new type of hydraulic piston is used to address the problem in which the hydraul...

  3. Auto-ignition of lubricating oil working at high pressures in a compressor for an air conditioner.

    Science.gov (United States)

    Kim, Chul Jin; Choi, Hyo Hyun; Sohn, Chae Hoon

    2011-01-15

    Auto-ignition of lubricating oil working in a compressor for an air conditioner is studied experimentally. The adopted lubricating oil is an unknown mixture with multi-components and known to have flash point temperature of 170 °C. First, its auto-ignition temperature is measured 365 °C at atmospheric pressure. The lubricating oil works under high-pressure condition up to 30 atm and it is heated and cooled down repeatedly. Accordingly, auto-ignition temperatures or flammable limits of lubricating oil are required at high pressures with respect to fire safety. Because there is not a standard test method for the purpose, a new ignition-test method is proposed in this study and thereby, auto-ignition temperatures are measured over the pressure range below 30 atm. The measured temperatures range from 215 °C to 255 °C and they strongly depend on pressure of gas mixture consisting of oil vapor, nitrogen, and oxygen. They are close to flash point temperature and the lubricating oil can be hazardous when it works for high-pressure operating condition and abundant air flows into a compressor. Copyright © 2010 Elsevier B.V. All rights reserved.

  4. Auto-ignition of lubricating oil working at high pressures in a compressor for an air conditioner

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chul Jin; Choi, Hyo Hyun [Department of Mechanical Engineering, Sejong University, Seoul 143-747 (Korea, Republic of); Sohn, Chae Hoon, E-mail: chsohn@sejong.ac.kr [Department of Mechanical Engineering, Sejong University, Seoul 143-747 (Korea, Republic of)

    2011-01-15

    Auto-ignition of lubricating oil working in a compressor for an air conditioner is studied experimentally. The adopted lubricating oil is an unknown mixture with multi-components and known to have flash point temperature of 170 deg. C. First, its auto-ignition temperature is measured 365 deg. C at atmospheric pressure. The lubricating oil works under high-pressure condition up to 30 atm and it is heated and cooled down repeatedly. Accordingly, auto-ignition temperatures or flammable limits of lubricating oil are required at high pressures with respect to fire safety. Because there is not a standard test method for the purpose, a new ignition-test method is proposed in this study and thereby, auto-ignition temperatures are measured over the pressure range below 30 atm. The measured temperatures range from 215 deg. C to 255 deg. C and they strongly depend on pressure of gas mixture consisting of oil vapor, nitrogen, and oxygen. They are close to flash point temperature and the lubricating oil can be hazardous when it works for high-pressure operating condition and abundant air flows into a compressor.

  5. Auto-ignition of lubricating oil working at high pressures in a compressor for an air conditioner

    International Nuclear Information System (INIS)

    Kim, Chul Jin; Choi, Hyo Hyun; Sohn, Chae Hoon

    2011-01-01

    Auto-ignition of lubricating oil working in a compressor for an air conditioner is studied experimentally. The adopted lubricating oil is an unknown mixture with multi-components and known to have flash point temperature of 170 deg. C. First, its auto-ignition temperature is measured 365 deg. C at atmospheric pressure. The lubricating oil works under high-pressure condition up to 30 atm and it is heated and cooled down repeatedly. Accordingly, auto-ignition temperatures or flammable limits of lubricating oil are required at high pressures with respect to fire safety. Because there is not a standard test method for the purpose, a new ignition-test method is proposed in this study and thereby, auto-ignition temperatures are measured over the pressure range below 30 atm. The measured temperatures range from 215 deg. C to 255 deg. C and they strongly depend on pressure of gas mixture consisting of oil vapor, nitrogen, and oxygen. They are close to flash point temperature and the lubricating oil can be hazardous when it works for high-pressure operating condition and abundant air flows into a compressor.

  6. An experimental and numerical analysis of the influence of the inlet temperature, equivalence ratio and compression ratio on the HCCI auto-ignition process of Primary Reference Fuels in an engine

    Energy Technology Data Exchange (ETDEWEB)

    Machrafi, Hatim [UPMC Universite Paris 06, LGPPTS, Ecole Nationale Superieure de Chimie de Paris, 11, rue de Pierre et Marie Curie, 75005 Paris (France); UPMC Universite Paris 06, Institut Jean Le Rond D' Alembert (France); Cavadiasa, Simeon [UPMC Universite Paris 06, Institut Jean Le Rond D' Alembert (France)

    2008-11-15

    In order to understand better the auto-ignition process in an HCCI engine, the influence of some important parameters on the auto-ignition is investigated. The inlet temperature, the equivalence ratio and the compression ratio were varied and their influence on the pressure, the heat release and the ignition delays were measured. The inlet temperature was changed from 25 to 70 C and the equivalence ratio from 0.18 to 0.41, while the compression ratio varied from 6 to 13.5. The fuels that were investigated were PRF40 and n-heptane. These three parameters appeared to decrease the ignition delays, with the inlet temperature having the least influence and the compression ratio the most. A previously experimentally validated reduced surrogate mechanism, for mixtures of n-heptane, iso-octane and toluene, has been used to explain observations of the auto-ignition process. The same kinetic mechanism is used to better understand the underlying chemical and physical phenomena that make the influence of a certain parameter change according to the operating conditions. This can be useful for the control of the auto-ignition process in an HCCI engine. (author)

  7. Third O2 addition reactions promote the low-temperature auto-ignition of n-alkanes

    KAUST Repository

    Wang, Zhandong

    2016-01-20

    Comprehensive low-temperature oxidation mechanisms are needed to accurately predict fuel auto-ignition properties. This paper studies the effects of a previously unconsidered third O2 addition reaction scheme on the simulated auto-ignition of n-alkanes. We demonstrate that this extended low-temperature oxidation scheme has a minor effect on the simulation of n-pentane ignition; however, its addition significantly improves the prediction of n-hexane auto-ignition under low-temperature rapid compression machine conditions. Additional simulations of n-hexane in a homogeneous charge compression ignition engine show that engine-operating parameters (e.g., intake temperature and combustion phasing) are significantly altered when the third O2 addition kinetic mechanism is considered. The advanced combustion phasing is initiated by the formation and destruction of additional radical chain-branching intermediates produced in the third O2 addition process, e.g. keto-dihydroperoxides and/or keto-hydroperoxy cyclic ethers. Our results indicate that third O2 addition reactions accelerate low-temperature radical chain branching at conditions of relevance to advance engine technologies, and therefore these chemical pathways should also be considered for n-alkanes with 6 or more carbon atoms. © 2015 The Combustion Institute.

  8. N-decane-air end-gas auto-ignition induced by flame propagation in a constant volume chamber: Influence of compression history

    OpenAIRE

    Quintens , Hugo; Strozzi , Camille; Zitoun , Ratiba; Bellenoue , Marc

    2017-01-01

    International audience; The present study aims at characterizing the end-gas auto-ignition of n-decane – air mixtures induced by a flame propagation in a constant volume chamber. A numerical tool is developed, and the study is first focused on academic compressions, e.g. at constant rate of pressure rise. Thermodynamic conditions of transition from deflagration to auto-ignition are first determined, and the involved physical processes are highlighted. A square section combustion chamber is th...

  9. Clementine auto exposure control software

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, E. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    The primary mission of the Clementine program was to test technology developed under the auspices of BMDO (the Ballistic Missile Defense Organization). A secondary goal of the program was to provide astronomical data to the scientific and educational community. The mission plan developed to accomplish these goals included complete mapping of the lunar surface and a close fly-by of a near-Earth asteroid, 1620 Geographos. Exposure control for the Clementine mission was driven by mission phase requirements and sensor characteristics. Thus, there were a total of twelve algorithms developed for three primary mission phases and the four imaging sensors (two additional sensors operated as star trackers). The three mission phases in question were lunar mapping, distant observation of the asteroid for the purpose of tracking, and close-up viewing (as close as 100 Km) of Geographos. The four non-star tracker sensors consisted of an Ultra Violet/Visible (UV/Vis) camera, a High Resolution (HiRes) camera with a built-in LIDAR (Light Detection And Ranging) unit, a Near Infrared (NIR) camera, and a Long Wave InfraRed (LWIR) camera. Due to lack of test time and uncertainties about the imaging environment, numerous input parameters were provided in the algorithms to allow extensive tuning of the exposure control during the mission.

  10. Laser induced plasma methodology for ignition control in direct injection sprays

    International Nuclear Information System (INIS)

    Pastor, José V.; García-Oliver, José M.; García, Antonio; Pinotti, Mattia

    2016-01-01

    Highlights: • Laser Induced Plasma Ignition system is designed and applied to a Diesel Spray. • A method for quantification of the system effectiveness and reliability is proposed. • The ignition system is optimized in atmospheric and engine-like conditions. • Higher system effectiveness is reached with higher ambient density. • The system is able to stabilize Diesel combustion compared to auto-ignition cases. - Abstract: New combustion modes for internal combustion engines represent one of the main fields of investigation for emissions control in transportation Industry. However, the implementation of lean fuel mixture condition and low temperature combustion in real engines is limited by different unsolved practical issues. To achieve an appropriate combustion phasing and cycle-to-cycle control of the process, the laser plasma ignition system arises as a valid alternative to the traditional electrical spark ignition system. This paper proposes a methodology to set-up and optimize a laser induced plasma ignition system that allows ensuring reliability through the quantification of the system effectiveness in the plasma generation and positional stability, in order to reach optimal ignition performance. For this purpose, experimental tests have been carried out in an optical test rig. At first the system has been optimized in an atmospheric environment, based on the statistical analysis of the plasma records taken with a high speed camera to evaluate the induction effectiveness and consequently regulate and control the system settings. The same optimization method has then been applied under engine-like conditions, analyzing the effect of thermodynamic ambient conditions on the plasma induction success and repeatability, which have shown to depend mainly on ambient density. Once optimized for selected engine conditions, the laser plasma induction system has been used to ignite a direct injection Diesel spray, and to compare the evolution of combustion

  11. An experimental and numerical analysis of the HCCI auto-ignition process of primary reference fuels, toluene reference fuels and diesel fuel in an engine, varying the engine parameters

    OpenAIRE

    Machrafi, Hatim; Cavadias, Simeon; Gilbert, Philippe

    2008-01-01

    For a future HCCI engine to operate under conditions that adhere to environmental restrictions, reducing fuel consumption and maintaining or increasing at the same time the engine efficiency, the choice of the fuel is crucial. For this purpose, this paper presents an auto-ignition investigation concerning the primary reference fuels, toluene reference fuels and diesel fuel, in order to study the effect of linear alkanes, branched alkanes and aromatics on the auto-ignition. The auto-ignition o...

  12. Progress of studies on preparation of TiO2 photocatalysts with sol-gel auto igniting synthesis

    Science.gov (United States)

    Wu, Di; Shi, Zaifeng; Zhang, Xiaopeng; Xinghui, Wu

    2017-11-01

    In this article, influencing factors on the kinetics of the process of Sol-gel Auto igniting Synthesis (SAS) which is an advanced technology for preparing nanometer particles of inorganic materials were reviewed. The studies on preparing of nanometer TiO2 photocatalysts with SAS were focused. It was concluded that SAS will play an important role in practical preparing of high-pure nanometer TiO2 powder, and as a technical support, preparation of titania TiO2 from titanic iron ore with SAS is feasible and practicable.

  13. AUTO

    DEFF Research Database (Denmark)

    Gammelgaard Nielsen, Anders; Aagaard, Tine; Diaz, pauline

    2011-01-01

    AUTO is the first assignment that the students of Architecture are introduced to at the Aarhus school of Architecture. The aim is to give students an understanding of design through a generic working method. This by disassembling a car engine and staging its components through a series of castings...

  14. Auto-Ignition and Combustion of Diesel Fuel in a Constant-Volume Bomb

    Science.gov (United States)

    Selden, Robert F

    1938-01-01

    Report presents the results of a study of variations in ignition lag and combustion associated with changes in air temperature and density for a diesel fuel in a constant-volume bomb. The test results have been discussed in terms of engine performance wherever comparisons could be drawn. The most important conclusions drawn from this investigation are: the ignition lag was essentially independent of the injected fuel quantity. Extrapolation of the curves for the fuel used shows that the lag could not be greatly decreased by exceeding the compression-ignition engines. In order to obtain the best combustion and thermal efficiency, it was desirable to use the longest ignition lag consistent with a permissible rate of pressure rise.

  15. Ignition analysis for burn control and diagnostic developments in ITER

    International Nuclear Information System (INIS)

    Mitarai, O.; Muraoka, K.

    1997-01-01

    The temporal evolutions of the operating point during the ignition access and ignited operation phases are analysed on the basis of zero dimensional (0-D) equations in order to clarify the requirements for safe control of ignited operation and for the development of diagnostic systems in ITER. A stable and safe method of reaching the ignited operating point is identified as the 'higher temperature access' method, being compatible with the H mode power threshold constraints. It is found that the ignition boundary can be experimentally determined by a 'thermonuclear oscillation' of the operating point without knowing the power balance equation. On the other hand, the ignition boundary determined by the power balance equation has a larger error bar depending on the accuracy of the diagnostic system. The plasma waveform response to sudden changes in the various plasma parameters during ignited operation is also calculated, and fusion power regulation is demonstrated by feedback control of the fuelling and auxiliary heating power. (author)

  16. Instrumentation and controls of an ignited tokamak

    International Nuclear Information System (INIS)

    Becraft, W.R.; Golzy, J.; Houlberg, W.A.; Kukielka, C.A.; Onega, R.J.; Raju, G.V.S.; Stone, R.S.

    1980-10-01

    The instrumentation and controls (I and C) of an ignited plasma magnetically confined in a tokamak configuration needs increased emphasis in the following areas: (1) physics implications for control; (2) plasma shaping/position control; and (3) control to prevent disruptive instabilities. This document reports on the FY 1979 efforts in these and other areas. Also presented are discusssions in the areas of: (1) diagnostics suitable for the Engineering Test Facility (ETF); and (2) future research and development (R and D) needs. The appendices focus attention on some preliminary ideas about the measurement of the deuteron-triton (D-T) ratio in the plasma, synchrotron radiation, and divertor control. Finally, an appendix documenting the thermal consequences to the first wall of a MPD is presented

  17. Ignition and burn control in tokamak plasmas

    International Nuclear Information System (INIS)

    Borrass, K.; Gruber, O.; Lackner, K.; Minardi, E.; Neuhauser, J.; Wilhelm, R.; Wunderlich, R.; Bromberg, L.; Cohn, D.R.

    1981-01-01

    Different schemes for the control of the thermal instability in an ignited fusion reactor are analysed by zero- and one-dimensional models. Passive stabilization methods considered are ripple-enhanced ion heat conduction, the effect of the major-radius variation of the plasma column in a time-independent vertical field, and the combination of both effects, including the spatial variation of the toroidal-ripple amplitude. Active control methods analysed are high-Q-driven operation and feedback-controlled major-radius variation following different scenarios. One-dimensional analyses taking into account only conductive losses show the existence of a single unstable mode in the energy balance, justifying, under these assumptions, the study of only global control. (author)

  18. Analysis of Auto ignition of Hydrogen-Air Mixture using Direct Numerical Simulation; Analisis de la Autoignicion de Mezclas Hidrogeno-Aire mediante Simulacion Numerica directa

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Vera, I.; Paola, G. de; Jimenez Sanchez, C.

    2008-07-01

    This document reproduces the final project of Ignacio Hernandez Vera, presented on September 25, 2008, for the obtention of the engineer degree of the Carlos III University of Madrid. A study on the auto ignition process of different hydrogen-air mixtures for different simple geometries is carried out by means of direct numerical simulation. Auto ignition time is compared for different configurations and it is discussed the influence that different parameters have on it, such as temperature or transport phenomena. Afterwards a new reduced chemical mechanism for the simulation of this phenomenon is tested and assessed. Finally the mixing and ignition process is tackled using different mixture fractions and its implications on the construction of combustion models briefly discussed. (Author) 15 refs.

  19. Auto-ignition of methane-air mixtures flowing along an array of thin catalytic plates

    Science.gov (United States)

    Treviño, C.

    2010-12-01

    In this paper, the heterogeneous ignition of a methane-air mixture flowing along an infinite array of catalytic parallel plates has been studied by inclusion of gas expansion effects and the finite heat conduction on the plates. The system of equations considers the full compressible Navier-Stokes equations coupled with the energy equations of the plates. The gas expansion effects which arise from temperature changes have been considered. The heterogeneous kinetics considers the adsorption and desorption reactions for both reactants. The limits of large and small longitudinal thermal conductance of the plate material are analyzed and the critical conditions for ignition are obtained in closed form. The governing equations are solved numerically using finite differences. The results show that ignition is more easily produced as the longitudinal wall thermal conductance increases, and the effects of the gas expansion on the catalytic ignition process are rather small due to the large value of the activation energy of the desorption reaction of adsorbed oxygen atoms.

  20. Nonlinear control of a spark ignition engine

    Energy Technology Data Exchange (ETDEWEB)

    Bidan, P [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France); Boverie, S; Chaumerliac, V [Siemens AutomotiveSA, MIRGAS Laboratory, 31 - Toulouse (France)

    1994-12-31

    This paper describes the improvements which can be made to spark ignition engine by extensive use of automatic control. Particular emphasis is placed on fast transient phases produced by simultaneous action on the throttle and the electronic fuel injection device. The aim is to achieve better performance for the fuel/air ratio regulation system, thereby improving engine efficiency and exhaust emission during these transient phases. The authors begin by presenting an average dynamic model of the intake manifold validated on an engine test bench and goes on to develop a closed-loop system controlling average pressure in the intake manifold using the reference tracking model method. The air supply control system is combined with a predictor to compensate for delays in the injection procedure. The paper concludes with a comparison between the results obtained using simulation and those obtained experimentally from the engine. (author) 10 refs.

  1. The development and experimental validation of a reduced ternary kinetic mechanism for the auto-ignition at HCCI conditions, proposing a global reaction path for ternary gasoline surrogates

    Energy Technology Data Exchange (ETDEWEB)

    Machrafi, Hatim; Cavadias, Simeon; Amouroux, Jacques [UPMC Universite Paris 06, LGPPTS, Ecole Nationale Superieure de Chimie de Paris, 11, rue de Pierre et Marie Curie, 75005 Paris (France)

    2009-02-15

    To acquire a high amount of information of the behaviour of the Homogeneous Charge Compression Ignition (HCCI) auto-ignition process, a reduced surrogate mechanism has been composed out of reduced n-heptane, iso-octane and toluene mechanisms, containing 62 reactions and 49 species. This mechanism has been validated numerically in a 0D HCCI engine code against more detailed mechanisms (inlet temperature varying from 290 to 500 K, the equivalence ratio from 0.2 to 0.7 and the compression ratio from 8 to 18) and experimentally against experimental shock tube and rapid compression machine data from the literature at pressures between 9 and 55 bar and temperatures between 700 and 1400 K for several fuels: the pure compounds n-heptane, iso-octane and toluene as well as binary and ternary mixtures of these compounds. For this validation, stoichiometric mixtures and mixtures with an equivalence ratio of 0.5 are used. The experimental validation is extended by comparing the surrogate mechanism to experimental data from an HCCI engine. A global reaction pathway is proposed for the auto-ignition of a surrogate gasoline, using the surrogate mechanism, in order to show the interactions that the three compounds can have with one another during the auto-ignition of a ternary mixture. (author)

  2. AutoCAD electrical 2013 for electrical control designers

    CERN Document Server

    Tickoo, Sham; CADCIM Technologies

    2013-01-01

    The AutoCAD Electrical 2013 for Electrical Control Designers textbook has been written to assist the engineering students and the practicing designers learn the application of various AutoCAD Electrical tools and options for creating electrical control designs. After reading this textbook, the users will be able to create professional electrical-control drawings easily and effectively. Moreover, the users will be able to automate various control engineering tasks such as building circuits, numbering wires, creating bills of materials, and many more. The textbook takes the users across a wide spectrum of electrical control drawings through progressive examples and numerous illustrations and exercises, thereby making it an ideal guide for both the novice and the advanced users. Salient Features of the Textbook Consists of 14 chapters that are organized in a pedagogical sequence covering various tools and features of AutoCAD Electrical such as schematic drawings, parametric and non-parametric PLC modules, Circu...

  3. A Phenomenological Model for Prediction Auto-Ignition and Soot Formation of Turbulent Diffusion Combustion in a High Pressure Common Rail Diesel Engine

    Directory of Open Access Journals (Sweden)

    Qinghui Zhou

    2011-06-01

    Full Text Available A new phenomenological model, the TP (Temperature Phase model, is presented to carry out optimization calculations for turbulent diffusion combustion in a high-pressure common rail diesel engine. Temperature is the most important parameter in the TP model, which includes two parts: an auto-ignition and a soot model. In the auto-ignition phase, different reaction mechanisms are built for different zones. For the soot model, different methods are used for different temperatures. The TP model is then implemented in KIVA code instead of original model to carry out optimization. The results of cylinder pressures, the corresponding heat release rates, and soot with variation of injection time, variation of rail pressure and variation of speed among TP model, KIVA standard model and experimental data are analyzed. The results indicate that the TP model can carry out optimization and CFD (computational fluid dynamics and can be a useful tool to study turbulent diffusion combustion.

  4. Lagrangian Investigation of Auto-ignition in a Hydrogen Jet Flame in a Vitiated Co-flow: Animations of Particle Trajectories in Composition Space from PDF Model Calculations

    OpenAIRE

    Wang, Haifeng; Pope, Stephen B.

    2007-01-01

    PDF model calculations have been performed of the Cabra lifted hydrogen flame in a vitiated co-flow. Particle trajectories are extracted from the Lagrangian particle method used to solve the modeled PDF equation. The particle trajectories in the mixture fraction-temperature plane reveal (at successive downstream locations): essentially inert mixing between the cold fuel jet and the hot co-flow; the auto-ignition of very lean particles; and, subsequent mixing and reaction, leading to near-equi...

  5. Plasma position control in a tokamak reactor around ignition

    International Nuclear Information System (INIS)

    Carretta, U.; Minardi, E.; Bacelli, N.

    1986-01-01

    Plasma position control in a tokamak reactor in the phase approaching ignition is closely related to burn control. If ignited burn corresponds to a thermally unstable situation the plasma becomes sensitive to the thermal instability already in the phase when ignition is approached so that the trajectory in the position-pressure (R,p) space becomes effectively unpredictable. For example, schemes involving closed cycles around ignition can be unstable in the heating-cooling phases, and the deviations may be cumulative in time. Reliable plasma control in pressure-position (p, R) space is achieved by beforehand constraining the p, R trajectory rigidly with suitable feedback vertical field stabilization, which is to be established already below ignition. A scheme in which ignition is approached in a stable and automatic way by feedback stabilization on the vertical field is proposed and studied in detail. The values of the gain coefficient ensuring stabilization and the associated p and R excursions are discussed both analytically, with a 0-D approximation including non-linear effects, and numerically with a 1-D code in cylindrical geometry. Profile effects increase the excursions, in particular above ignition. (author)

  6. Experimental and Numerical Study of Jet Controlled Compression Ignition on Combustion Phasing Control in Diesel Premixed Compression Ignition Systems

    OpenAIRE

    Qiang Zhang; Wuqiang Long; Jiangping Tian; Yicong Wang; Xiangyu Meng

    2014-01-01

    In order to directly control the premixed combustion phasing, a Jet Controlled Compression Ignition (JCCI) for diesel premixed compression ignition systems is investigated. Experiments were conducted on a single cylinder natural aspirated diesel engine without EGR at 3000 rpm. Numerical models were validated by load sweep experiments at fixed spark timing. Detailed combustion characteristics were analyzed based on the BMEP of 2.18 bar. The simulation results showed that the high temperature j...

  7. An experimental and numerical analysis of the influence of the inlet temperature, equivalence ratio and compression ratio on the HCCI auto-ignition process of Primary Reference Fuels in an engine

    OpenAIRE

    Machrafi, Hatim; Cavadias

    2008-01-01

    In order to understand better the auto-ignition process in an HCCI engine, the influence of some important parameters on the auto-ignition is investigated. The inlet temperature, the equivalence ratio and the compression ratio were varied and their influence on the pressure, the heat release and the ignition delays were measured, The inlet temperature was changed from 25 to 70 degrees C and the equivalence ratio from 0.18 to 0.41, while the compression ratio varied from 6 to 13.5. The fuels t...

  8. Experimental and Numerical Study of Jet Controlled Compression Ignition on Combustion Phasing Control in Diesel Premixed Compression Ignition Systems

    Directory of Open Access Journals (Sweden)

    Qiang Zhang

    2014-07-01

    Full Text Available In order to directly control the premixed combustion phasing, a Jet Controlled Compression Ignition (JCCI for diesel premixed compression ignition systems is investigated. Experiments were conducted on a single cylinder natural aspirated diesel engine without EGR at 3000 rpm. Numerical models were validated by load sweep experiments at fixed spark timing. Detailed combustion characteristics were analyzed based on the BMEP of 2.18 bar. The simulation results showed that the high temperature jets of reacting active radical species issued from the ignition chamber played an important role on the onset of combustion in the JCCI system. The combustion of diesel pre-mixtures was initiated rapidly by the combustion products issued from the ignition chamber. Moreover, the flame propagation was not obvious, similar to that in Pre-mixed Charge Compression Ignition (PCCI. Consequently, spark timing sweep experiments were conducted. The results showed a good linear relationship between spark timing in the ignition chamber and CA10 and CA50, which indicated the ability for direct combustion phasing control in diesel PCCI. The NOx and soot emissions gradually changed with the decrease of spark advance angle. The maximum reduction of NOx and soot were both over 90%, and HC and CO emissions were increased.

  9. Analysis of Hydrogen Control Strategy Using Igniter during Severe Accident

    International Nuclear Information System (INIS)

    Lee, Sung Bok; Kim, Hyeong Taek; Lee, Keo Hyoung

    2008-01-01

    The Severe Accident Management Guidelines (SAMGs) for the operating pressurized water reactor (PWR) have been completed within 2006. Among the SAMG strategies, mitigation-07 is the most important strategy for managing a severe accident of a PWR in order to reduce containment hydrogen. The fastest way to reduce the containment hydrogen concentration is to intentionally ignite the hydrogen. For this strategy, igniters exist in Optimized Power Reactor 1000 (OPR 1000) to burn hydrogen for a severe accident. For using the igniters during a severe accident, the adverse effects such as the explosion of the hydrogen mixture should be considered for containment integrity. However, an applicable discrimination method to activate the igniters does not exist, so that the hydrogen control strategy using the igniters cannot be chosen during a severe accident. Thus, this study focused on suggesting an applicable discrimination method to carry out the strategy of using the igniters. In this study, the specific plant used for this analysis is Ulchin Unit 5 and 6, OPR 1000 plant, in Korea

  10. Towards constrained optimal control of spark-ignition engines

    NARCIS (Netherlands)

    Feru, E.; Luo, X.

    2015-01-01

    In this paper, the torque control problem for spark-ignition engines is considered. The objective is to provide good output torque tracking with minimum fuel consumption, while avoiding engine knock and misre. To this end, three control strategies are proposed: a feed-forward controller with

  11. A computational study of syngas auto-ignition characteristics at high-pressure and low-temperature conditions with thermal inhomogeneities

    KAUST Repository

    Pal, Pinaki

    2015-07-30

    A computational study was conducted to investigate the characteristics of auto-ignition in a syngas mixture at high-pressure and low-temperature conditions in the presence of thermal inhomogeneities. Highly resolved one-dimensional numerical simulations incorporating detailed chemistry and transport were performed. The temperature inhomogeneities were represented by a global sinusoidal temperature profile and a local Gaussian temperature spike (hot spot). Reaction front speed and front Damköhler number analyses were employed to characterise the propagating ignition front. In the presence of a global temperature gradient, the ignition behaviour shifted from spontaneous propagation (strong) to deflagrative (weak), as the initial mean temperature of the reactant mixture was lowered. A predictive Zel\\'dovich–Sankaran criterion to determine the transition from strong to weak ignition was validated for different parametric sets. At sufficiently low temperatures, the strong ignition regime was recovered due to faster passive scalar dissipation of the imposed thermal fluctuations relative to the reaction timescale, which was quantified by the mixing Damköhler number. In the presence of local hot spots, only deflagrative fronts were observed. However, the fraction of the reactant mixture consumed by the propagating front was found to increase as the initial mean temperature was lowered, thereby leading to more enhanced compression-heating of the end-gas. Passive scalar mixing was not found to be important for the hot spot cases considered. The parametric study confirmed that the relative magnitude of the Sankaran number translates accurately to the quantitative strength of the deflagration front in the overall ignition advancement. © 2015 Taylor & Francis

  12. A computational study of syngas auto-ignition characteristics at high-pressure and low-temperature conditions with thermal inhomogeneities

    Science.gov (United States)

    Pal, Pinaki; Mansfield, Andrew B.; Arias, Paul G.; Wooldridge, Margaret S.; Im, Hong G.

    2015-09-01

    A computational study was conducted to investigate the characteristics of auto-ignition in a syngas mixture at high-pressure and low-temperature conditions in the presence of thermal inhomogeneities. Highly resolved one-dimensional numerical simulations incorporating detailed chemistry and transport were performed. The temperature inhomogeneities were represented by a global sinusoidal temperature profile and a local Gaussian temperature spike (hot spot). Reaction front speed and front Damköhler number analyses were employed to characterise the propagating ignition front. In the presence of a global temperature gradient, the ignition behaviour shifted from spontaneous propagation (strong) to deflagrative (weak), as the initial mean temperature of the reactant mixture was lowered. A predictive Zel'dovich-Sankaran criterion to determine the transition from strong to weak ignition was validated for different parametric sets. At sufficiently low temperatures, the strong ignition regime was recovered due to faster passive scalar dissipation of the imposed thermal fluctuations relative to the reaction timescale, which was quantified by the mixing Damköhler number. In the presence of local hot spots, only deflagrative fronts were observed. However, the fraction of the reactant mixture consumed by the propagating front was found to increase as the initial mean temperature was lowered, thereby leading to more enhanced compression-heating of the end-gas. Passive scalar mixing was not found to be important for the hot spot cases considered. The parametric study confirmed that the relative magnitude of the Sankaran number translates accurately to the quantitative strength of the deflagration front in the overall ignition advancement.

  13. AutoCAD electrical 2016 for electrical control designers

    CERN Document Server

    Tickoo, Sham

    2016-01-01

    The AutoCAD Electrical 2016 for Electrical Control Designers textbook has been written to assist the engineering students and the practicing designers who are new to AutoCAD Electrical. Using this textbook, the readers can learn the application of basic tools required for creating professional electrical control drawings with the help of AutoCAD Electrical. Keeping in view the varied requirements of the users, this textbook covers a wide range of tools and features such as schematic drawings, Circuit Builder, panel drawings, parametric and nonparametric PLC modules, stand-alone PLC I/O points, ladder diagrams, point-to-point wiring diagrams, report generation, creation of symbols, and so on. This will help the readers to create electrical drawings easily and effectively. Special emphasis has been laid on the introduction of concepts, which have been explained using text and supported with graphical examples. The examples and tutorials used in this book ensure that the users can relate the information provided...

  14. Status of the National Ignition Facility Integrated Computer Control System (ICCS) on the Path to Ignition

    International Nuclear Information System (INIS)

    Lagin, L J; Bettenhauasen, R C; Bowers, G A; Carey, R W; Edwards, O D; Estes, C M; Demaret, R D; Ferguson, S W; Fisher, J M; Ho, J C; Ludwigsen, A P; Mathisen, D G; Marshall, C D; Matone, J M; McGuigan, D L; Sanchez, R J; Shelton, R T; Stout, E A; Tekle, E; Townsend, S L; Van Arsdall, P J; Wilson, E F

    2007-01-01

    The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory is a stadium-sized facility under construction that will contain a 192-beam, 1.8-Megajoule, 500-Terawatt, ultraviolet laser system together with a 10-meter diameter target chamber with room for multiple experimental diagnostics. NIF is the world's largest and most energetic laser experimental system, providing a scientific center to study inertial confinement fusion (ICF) and matter at extreme energy densities and pressures. NIF's laser beams are designed to compress fusion targets to conditions required for thermonuclear burn, liberating more energy than required to initiate the fusion reactions. NIF is comprised of 24 independent bundles of 8 beams each using laser hardware that is modularized into more than 6,000 line replaceable units such as optical assemblies, laser amplifiers, and multifunction sensor packages containing 60,000 control and diagnostic points. NIF is operated by the large-scale Integrated Computer Control System (ICCS) in an architecture partitioned by bundle and distributed among over 800 front-end processors and 50 supervisory servers. NIF's automated control subsystems are built from a common object-oriented software framework based on CORBA distribution that deploys the software across the computer network and achieves interoperation between different languages and target architectures. A shot automation framework has been deployed during the past year to orchestrate and automate shots performed at the NIF using the ICCS. In December 2006, a full cluster of 48 beams of NIF was fired simultaneously, demonstrating that the independent bundle control system will scale to full scale of 192 beams. At present, 72 beams have been commissioned and have demonstrated 1.4-Megajoule capability of infrared light. During the next two years, the control system will be expanded to include automation of target area systems including final optics, target positioners and

  15. Status of the National Ignition Facility Integrated Computer Control System (ICCS) on the path to ignition

    International Nuclear Information System (INIS)

    Lagin, L.J.; Bettenhausen, R.C.; Bowers, G.A.; Carey, R.W.; Edwards, O.D.; Estes, C.M.; Demaret, R.D.; Ferguson, S.W.; Fisher, J.M.; Ho, J.C.; Ludwigsen, A.P.; Mathisen, D.G.; Marshall, C.D.; Matone, J.T.; McGuigan, D.L.; Sanchez, R.J.; Stout, E.A.; Tekle, E.A.; Townsend, S.L.; Van Arsdall, P.J.

    2008-01-01

    The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory is a stadium-sized facility under construction that will contain a 192-beam, 1.8-MJ, 500-TW, ultraviolet laser system together with a 10-m diameter target chamber with room for multiple experimental diagnostics. NIF is the world's largest and most energetic laser experimental system, providing a scientific center to study inertial confinement fusion (ICF) and matter at extreme energy densities and pressures. NIF's laser beams are designed to compress fusion targets to conditions required for thermonuclear burn, liberating more energy than required to initiate the fusion reactions. NIF is comprised of 24 independent bundles of eight beams each using laser hardware that is modularized into more than 6000 line replaceable units such as optical assemblies, laser amplifiers, and multi-function sensor packages containing 60,000 control and diagnostic points. NIF is operated by the large-scale Integrated Computer Control System (ICCS) in an architecture partitioned by bundle and distributed among over 800 front-end processors and 50 supervisory servers. NIF's automated control subsystems are built from a common object-oriented software framework based on CORBA distribution that deploys the software across the computer network and achieves interoperation between different languages and target architectures. A shot automation framework has been deployed during the past year to orchestrate and automate shots performed at the NIF using the ICCS. In December 2006, a full cluster of 48 beams of NIF was fired simultaneously, demonstrating that the independent bundle control system will scale to full scale of 192 beams. At present, 72 beams have been commissioned and have demonstrated 1.4-MJ capability of infrared light. During the next 2 years, the control system will be expanded in preparation for project completion in 2009 to include automation of target area systems including final optics

  16. Auto-control experiments on DIDO using discontinuous feedback

    International Nuclear Information System (INIS)

    Lawrence, L.A.J.

    1959-12-01

    Experiments on auto-controlling the reactor DIDO are described and the equipment design discussed in some detail. The experiments are carried out to show the suitability of an on/off type of control for the maintenance of: (a) a constant flux level in the presence of noise. (b) constant period during power change. The controlling signals stem from measurement of neutron flux computed to give deviation from demanded power, and period respectively. These signals are fed to a D.C. amplifier with variable deadbang whose output is used to control relays, these in turn control the coarse control arms by means of three-phase motors. The system is designed on the basis of locus diagrams, a conventional non-linear technique being used to handle the relay performance. Calculation of the reactor transfer function at high and low power respectively shows that the stability margin is not appreciably affected by the inherent thermodynamic feedback in the reactor core. (author)

  17. Controlling the ignition and flammability of magnesium for aerospace applications

    International Nuclear Information System (INIS)

    Czerwinski, Frank

    2014-01-01

    The perceived easy ignition and flammability of magnesium alloys create a detrimental safety feature that overshadows their high strength-to-weight ratio and hinders the aerospace application opportunities. To overcome the existing barriers a progress in understanding and controlling the reactivity of magnesium at high temperatures is required. This report describes fundamentals of magnesium ignition and flammability along with laboratory testing procedures and correlations with full scale fire scenarios, related in particular to the aircraft cabin. The influence of alloying elements on high temperature reactivity of magnesium and global efforts to develop ignition resistant and non-flammable magnesium alloys are reviewed. Although ignition and flammability represent quite different quantities, both are controlled by an oxidation resistance of the alloy and its capability to form a dense and protective surface oxide after exposures to an open flame or other heat source. Since surface oxide, composed of pure MgO, does not offer a sufficient protection, the research strategy is focused on modification of its chemistry and microstructure by micro-alloying the substrate with rare earths and other elements having high affinity to oxygen

  18. Ignition and burn control characteristics of thermonuclear plasmas

    International Nuclear Information System (INIS)

    Chaniotakis, E.A.

    1990-01-01

    Achieving the long sought goal of fusion energy requires the attainment of an ignited and controlled thermonuclear plasma. Obtaining an ignited plasma in a tokamak device requires consideration of both the physics of the plasma and the engineering of the machine. With the aide of completely analytical procedure optimized and ignited tokamaks are obtained under various physics assumptions. These designs show the possible advantage of tokamaks characterized by high (∼4.5) aspect ratio, and high (∼15 T) toroidal magnetic field. The control of an ignited plasma is investigated by using auxiliary power modulation. With auxiliary power stable operating points can be created with Q ∼50. Recognizing the need for a fast 1 1/2-D transport model for studying profile effects the plasma transport equations are solved using variational methods. A computer model based on the variational method has been developed. This model solves the 1 1/2-D transport equation very fast with little loss of accuracy. 74 refs., 70 figs., 8 tabs

  19. National Ignition Facility integrated computer control system

    International Nuclear Information System (INIS)

    Van Arsdall, P.J. LLNL

    1998-01-01

    The NIF design team is developing the Integrated Computer Control System (ICCS), which is based on an object-oriented software framework applicable to event-driven control systems. The framework provides an open, extensible architecture that is sufficiently abstract to construct future mission-critical control systems. The ICCS will become operational when the first 8 out of 192 beams are activated in mid 2000. The ICCS consists of 300 front-end processors attached to 60,000 control points coordinated by a supervisory system. Computers running either Solaris or VxWorks are networked over a hybrid configuration of switched fast Ethernet and asynchronous transfer mode (ATM). ATM carries digital motion video from sensors to operator consoles. Supervisory software is constructed by extending the reusable framework components for each specific application. The framework incorporates services for database persistence, system configuration, graphical user interface, status monitoring, event logging, scripting language, alert management, and access control. More than twenty collaborating software applications are derived from the common framework. The framework is interoperable among different kinds of computers and functions as a plug-in software bus by leveraging a common object request brokering architecture (CORBA). CORBA transparently distributes the software objects across the network. Because of the pivotal role played, CORBA was tested to ensure adequate performance

  20. Fault tolerant control of multivariable processes using auto-tuning PID controller.

    Science.gov (United States)

    Yu, Ding-Li; Chang, T K; Yu, Ding-Wen

    2005-02-01

    Fault tolerant control of dynamic processes is investigated in this paper using an auto-tuning PID controller. A fault tolerant control scheme is proposed composing an auto-tuning PID controller based on an adaptive neural network model. The model is trained online using the extended Kalman filter (EKF) algorithm to learn system post-fault dynamics. Based on this model, the PID controller adjusts its parameters to compensate the effects of the faults, so that the control performance is recovered from degradation. The auto-tuning algorithm for the PID controller is derived with the Lyapunov method and therefore, the model predicted tracking error is guaranteed to converge asymptotically. The method is applied to a simulated two-input two-output continuous stirred tank reactor (CSTR) with various faults, which demonstrate the applicability of the developed scheme to industrial processes.

  1. Image registration with auto-mapped control volumes

    International Nuclear Information System (INIS)

    Schreibmann, Eduard; Xing Lei

    2006-01-01

    Many image registration algorithms rely on the use of homologous control points on the two input image sets to be registered. In reality, the interactive identification of the control points on both images is tedious, difficult, and often a source of error. We propose a two-step algorithm to automatically identify homologous regions that are used as a priori information during the image registration procedure. First, a number of small control volumes having distinct anatomical features are identified on the model image in a somewhat arbitrary fashion. Instead of attempting to find their correspondences in the reference image through user interaction, in the proposed method, each of the control regions is mapped to the corresponding part of the reference image by using an automated image registration algorithm. A normalized cross-correlation (NCC) function or mutual information was used as the auto-mapping metric and a limited memory Broyden-Fletcher-Goldfarb-Shanno algorithm (L-BFGS) was employed to optimize the function to find the optimal mapping. For rigid registration, the transformation parameters of the system are obtained by averaging that derived from the individual control volumes. In our deformable calculation, the mapped control volumes are treated as the nodes or control points with known positions on the two images. If the number of control volumes is not enough to cover the whole image to be registered, additional nodes are placed on the model image and then located on the reference image in a manner similar to the conventional BSpline deformable calculation. For deformable registration, the established correspondence by the auto-mapped control volumes provides valuable guidance for the registration calculation and greatly reduces the dimensionality of the problem. The performance of the two-step registrations was applied to three rigid registration cases (two PET-CT registrations and a brain MRI-CT registration) and one deformable registration of

  2. Automatic detection of AutoPEEP during controlled mechanical ventilation

    Directory of Open Access Journals (Sweden)

    Nguyen Quang-Thang

    2012-06-01

    Full Text Available Abstract Background Dynamic hyperinflation, hereafter called AutoPEEP (auto-positive end expiratory pressure with some slight language abuse, is a frequent deleterious phenomenon in patients undergoing mechanical ventilation. Although not readily quantifiable, AutoPEEP can be recognized on the expiratory portion of the flow waveform. If expiratory flow does not return to zero before the next inspiration, AutoPEEP is present. This simple detection however requires the eye of an expert clinician at the patient’s bedside. An automatic detection of AutoPEEP should be helpful to optimize care. Methods In this paper, a platform for automatic detection of AutoPEEP based on the flow signal available on most of recent mechanical ventilators is introduced. The detection algorithms are developed on the basis of robust non-parametric hypothesis testings that require no prior information on the signal distribution. In particular, two detectors are proposed: one is based on SNT (Signal Norm Testing and the other is an extension of SNT in the sequential framework. The performance assessment was carried out on a respiratory system analog and ex-vivo on various retrospectively acquired patient curves. Results The experiment results have shown that the proposed algorithm provides relevant AutoPEEP detection on both simulated and real data. The analysis of clinical data has shown that the proposed detectors can be used to automatically detect AutoPEEP with an accuracy of 93% and a recall (sensitivity of 90%. Conclusions The proposed platform provides an automatic early detection of AutoPEEP. Such functionality can be integrated in the currently used mechanical ventilator for continuous monitoring of the patient-ventilator interface and, therefore, alleviate the clinician task.

  3. National Ignition Facility Control and Information System Operational Tools

    International Nuclear Information System (INIS)

    Marshall, C.D.; Beeler, R.G.; Bowers, G.A.; Carey, R.W.; Fisher, J.M.; Foxworthy, C.B.; Frazier, T.M.; Mathisen, D.G.; Lagin, L.J.; Rhodes, J.J.; Shaw, M.J.

    2009-01-01

    The National Ignition Facility (NIF) in Livermore, California, is the world's highest-energy laser fusion system and one of the premier large scale scientific projects in the United States. The system is designed to setup and fire a laser shot to a fusion ignition or high energy density target at rates up to a shot every 4 hours. NIF has 192 laser beams delivering up to 1.8 MJ of energy to a ∼2 mm target that is planned to produce >100 billion atm of pressure and temperatures of >100 million degrees centigrade. NIF is housed in a ten-story building footprint the size of three football fields as shown in Fig. 1. Commissioning was recently completed and NIF will be formally dedicated at Lawrence Livermore National Laboratory on May 29, 2009. The control system has 60,000 hardware controls points and employs 2 million lines of control system code. The control room has highly automated equipment setup prior to firing laser system shots. This automation has a data driven implementation that is conducive to dynamic modification and optimization depending on the shot goals defined by the end user experimenters. NIF has extensive facility machine history and infrastructure maintenance workflow tools both under development and deployed. An extensive operational tools suite has been developed to support facility operations including experimental shot setup, machine readiness, machine health and safety, and machine history. The following paragraphs discuss the current state and future upgrades to these four categories of operational tools.

  4. Comprehensive Auto CAD

    International Nuclear Information System (INIS)

    Jang, Taekju

    1993-06-01

    This book starts introduction of conception, application system, software for CAD, function of Auto CAD, kinds and function of Auto CAD files. It deals with starting of Auto CAD, dialogue box and Auto CAD interface, utility command, 2D drawing command, check command, control system, dimension, hatching command, layer command, block, 3D drawing, plotting and printing, auto CAD and application of data, supply program of auto CAD, AME and region modeler, EDLIN, script optimization of Auto CAD and composition on demand.

  5. Impact of fuel molecular structure on auto-ignition behavior – Design rules for future high performance gasolines

    KAUST Repository

    Boot, Michael D.

    2016-12-29

    At a first glance, ethanol, toluene and methyl tert-butyl ether look nothing alike with respect to their molecular structures. Nevertheless, all share a similarly high octane number. A comprehensive review of the inner workings of such octane boosters has been long overdue, particularly at a time when feedstocks for transport fuels other than crude oil, such as natural gas and biomass, are enjoying a rapidly growing market share. As high octane fuels sell at a considerable premium over gasoline, diesel and jet fuel, new entrants into the refining business should take note and gear their processes towards knock resistant compounds if they are to maximize their respective bottom lines. Starting from crude oil, the route towards this goal is well established. Starting from biomass or natural gas, however, it is less clear what dots on the horizon to aim for. The goal of this paper is to offer insight into the chemistry behind octane boosters and to subsequently distill from this knowledge, taking into account recent advances in engine technology, multiple generic design rules that guarantee good anti-knock performance. Careful analysis of the literature suggests that highly unsaturated (cyclic) compounds are the preferred octane boosters for modern spark-ignition engines. Additional side chains of any variety will dilute this strong performance. Multi-branched paraffins come in distant second place, owing to their negligible sensitivity. Depending on the type and location of functional oxygen groups, oxygenates can have a beneficial, neutral or detrimental impact on anti-knock quality.

  6. Computational characterization of ignition regimes in a syngas/air mixture with temperature fluctuations

    KAUST Repository

    Pal, Pinaki

    2016-07-27

    Auto-ignition characteristics of compositionally homogeneous reactant mixtures in the presence of thermal non-uniformities and turbulent velocity fluctuations were computationally investigated. The main objectives were to quantify the observed ignition characteristics and numerically validate the theory of the turbulent ignition regime diagram recently proposed by Im et al. 2015 [29] that provides a framework to predict ignition behavior . a priori based on the thermo-chemical properties of the reactant mixture and initial flow and scalar field conditions. Ignition regimes were classified into three categories: . weak (where deflagration is the dominant mode of fuel consumption), . reaction-dominant strong, and . mixing-dominant strong (where volumetric ignition is the dominant mode of fuel consumption). Two-dimensional (2D) direct numerical simulations (DNS) of auto-ignition in a lean syngas/air mixture with uniform mixture composition at high-pressure, low-temperature conditions were performed in a fixed volume. The initial conditions considered two-dimensional isotropic velocity spectrums, temperature fluctuations and localized thermal hot spots. A number of parametric test cases, by varying the characteristic turbulent Damköhler and Reynolds numbers, were investigated. The evolution of the auto-ignition phenomena, pressure rise, and heat release rate were analyzed. In addition, combustion mode analysis based on front propagation speed and computational singular perturbation (CSP) was applied to characterize the auto-ignition phenomena. All results supported that the observed ignition behaviors were consistent with the expected ignition regimes predicted by the theory of the regime diagram. This work provides new high-fidelity data on syngas ignition characteristics over a broad range of conditions and demonstrates that the regime diagram serves as a predictive guidance in the understanding of various physical and chemical mechanisms controlling auto-ignition

  7. Design of auto-control high-voltage control system of pulsed neutron generator

    International Nuclear Information System (INIS)

    Lv Juntao

    2008-01-01

    It is difficult to produce multiple anode controlling time sequences under different logging mode for the high-voltage control system of the conventional pulsed neutron generator. It is also difficult realize sequential control among anode high-voltage, filament power supply and target voltage to make neutron yield stable. To these problems, an auto-control high-voltage system of neutron pulsed generator was designed. It not only can achieve anode high-voltage double blast time sequences, which can measure multiple neutron blast time sequences such as Σ, activated spectrum, etc. under inelastic scattering mode, but also can realize neutron generator real-time measurement of multi-state parameters and auto-control such as target voltage pulse width modulation (PWM), filament current, anode current, etc., there by it can produce stable neutron yield and realize stable and accurate measurement of the pulsed neutron full spectral loging tool. (authors)

  8. Dynamic control of a homogeneous charge compression ignition engine

    Science.gov (United States)

    Duffy, Kevin P [Metamora, IL; Mehresh, Parag [Peoria, IL; Schuh, David [Peoria, IL; Kieser, Andrew J [Morton, IL; Hergart, Carl-Anders [Peoria, IL; Hardy, William L [Peoria, IL; Rodman, Anthony [Chillicothe, IL; Liechty, Michael P [Chillicothe, IL

    2008-06-03

    A homogenous charge compression ignition engine is operated by compressing a charge mixture of air, exhaust and fuel in a combustion chamber to an autoignition condition of the fuel. The engine may facilitate a transition from a first combination of speed and load to a second combination of speed and load by changing the charge mixture and compression ratio. This may be accomplished in a consecutive engine cycle by adjusting both a fuel injector control signal and a variable valve control signal away from a nominal variable valve control signal. Thereafter in one or more subsequent engine cycles, more sluggish adjustments are made to at least one of a geometric compression ratio control signal and an exhaust gas recirculation control signal to allow the variable valve control signal to be readjusted back toward its nominal variable valve control signal setting. By readjusting the variable valve control signal back toward its nominal setting, the engine will be ready for another transition to a new combination of engine speed and load.

  9. Development of a self-ignition and combustion model for diesel engines; Modelisation de l`auto-inflammation et de la combustion pour les moteurs diesel

    Energy Technology Data Exchange (ETDEWEB)

    Pires Da Cruz, A.

    1997-12-09

    The work concerns self-ignition and combustion modelling in Diesel engines. Special attention is given to turbulence induced effects. Only gas fuel injection is taken into account. Turbulent mixing is identified as one of the main parameters controlling self-ignition in Diesel engines. However, turbulence effects are often neglected by models currently used in engine calculation codes. A new model based on results obtained by direct numerical simulation (DNS) is proposed. It includes turbulence effects by means of the scalar dissipation rate and presumed pdf of the mixture fraction and a chemical reaction progress variable. The model is validated through several steps. First, its results are compared to DNS in simple mixing and self-ignition cases. Then, its averaged version is integrated into the KIVA2-MB calculation code, where its behavior is tested in a one dimensional version and compared to other formulations. Finally, the model is validated with comparisons to experimental results of methane injection into a high pressure combustion chamber filled with hot air. The combustion chamber allows large optical access and therefore, optical diagnostics can be made. (author) 101 refs.

  10. Low temperature oxidation, co-oxidation and auto-ignition of olefinic and aromatic blending compounds: Experimental study of interactions during the oxidation of a surrogate fuel; Oxydation, co-oxydation et auto-inflammation a basses temperatures d'alcenes et aromatiques types: etude experimentale des interactions au sein d'un carburant-modele

    Energy Technology Data Exchange (ETDEWEB)

    Vanhove, G.

    2004-12-15

    The low-temperature (600-900 K) and high-pressure (5-25 bar) oxidation and auto-ignition of the three position isomers of hexene, of binary mixtures of 1-hexene, toluene and iso-octane, and of a surrogate fuel composed of these three compounds were studied in motor conditions using a rapid compression machine. Auto-ignition delay times were measured as long as intermediate products concentrations during the delay. The results show that the oxidation chemistry of the hexenes is very dependent on the position of the double bond inside the molecule, and that strong interactions between the oxidation mechanisms of hydrocarbons in mixtures can occur. The data obtained concerning the surrogate fuel give a good insight into the behaviour of a practical gasoline after an homogeneous charge compression. (author)

  11. Remote control flare stack igniter for combustible gases

    Science.gov (United States)

    Ray, W. L.

    1972-01-01

    Device has been designed and developed for igniting nonrecoverable combustible gases and sustaining combustion of gases evolving from various gas vent stacks. Igniter is superior to existing systems because of simplicity of operation, low cost fabrication, installation, operational and maintainability features, and excellent reliability in all phases of required operations.

  12. National Ignition Facility (NIF) Control Network Design and Analysis

    International Nuclear Information System (INIS)

    Bryant, R M; Carey, R W; Claybourn, R V; Pavel, G; Schaefer, W J

    2001-01-01

    The control network for the National Ignition Facility (NIF) is designed to meet the needs for common object request broker architecture (CORBA) inter-process communication, multicast video transport, device triggering, and general TCP/IP communication within the NIF facility. The network will interconnect approximately 650 systems, including the embedded controllers, front-end processors (FEPs), supervisory systems, and centralized servers involved in operation of the NIF. All systems are networked with Ethernet to serve the majority of communication needs, and asynchronous transfer mode (ATM) is used to transport multicast video and synchronization triggers. CORBA software infra-structure provides location-independent communication services over TCP/IP between the application processes in the 15 supervisory and 300 FEP systems. Video images sampled from 500 video cameras at a 10-Hz frame rate will be multicast using direct ATM Application Programming Interface (API) communication from video FEPs to any selected operator console. The Ethernet and ATM control networks are used to broadcast two types of device triggers for last-second functions in a large number of FEPs, thus eliminating the need for a separate infrastructure for these functions. Analysis, design, modeling, and testing of the NIF network has been performed to provide confidence that the network design will meet NIF control requirements

  13. A computational study of syngas auto-ignition characteristics at high-pressure and low-temperature conditions with thermal inhomogeneities

    KAUST Repository

    Pal, Pinaki; Mansfield, Andrew B.; Arias, Paul G.; Wooldridge, Margaret S.; Im, Hong G.

    2015-01-01

    number analyses were employed to characterise the propagating ignition front. In the presence of a global temperature gradient, the ignition behaviour shifted from spontaneous propagation (strong) to deflagrative (weak), as the initial mean temperature

  14. An Auto Tuning Substation Peak Shaving Controller for Congestion Management Using Flexible Demand

    DEFF Research Database (Denmark)

    Sossan, Fabrizio; Marinelli, Mattia

    2013-01-01

    A closed loop substation peak shaving/congestion management controller for radial distribution networks is presented. The controller it uses an individual control signal in order to shift the consumption of a population of demand side resources, DSRs. The controller auto tunes its parameters on...

  15. Design of an adaptive backstepping controller for auto-berthing a cruise ship under wind loads

    Directory of Open Access Journals (Sweden)

    Park Jong-Yong

    2014-06-01

    Full Text Available The auto-berthing of a ship requires excellent control for safe accomplishment. Crabbing, which is the pure sway motion of a ship without surge velocity, can be used for this purpose. Crabbing is induced by a peculiar operation procedure known as the push-pull mode. When a ship is in the push-pull mode, an interacting force is induced by complex turbulent flow around the ship generated by the propellers and side thrusters. In this paper, three degrees of freedom equations of the motions of crabbing are derived. The equations are used to apply the adaptive backstepping control method to the auto-berthing controller of a cruise ship. The controller is capable of handling the system nonlinearity and uncertainty of the berthing process. A control allocation algorithm for a ship equipped with two propellers and two side thrusters is also developed, the performance of which is validated by simulation of auto-berthing.

  16. A comparison of Reactivity Controlled Compression Ignition (RCCI) and Gasoline Compression Ignition (GCI) strategies at high load, low speed conditions

    International Nuclear Information System (INIS)

    Kavuri, Chaitanya; Paz, Jordan; Kokjohn, Sage L.

    2016-01-01

    Highlights: • Targeting high load-low speed, optimizations of RCCI and GCI strategies were performed. • The two strategies were compared in terms of performance, controllability and stability. • The optimum cases had high gross indicated efficiency (∼47%) and low NOx emissions. • RCCI strategy showed better combustion control but had higher soot emissions. • GCI strategy was relatively more sensitive to fluctuations in charge conditions. - Abstract: Past research has shown that Reactivity Controlled Compression Ignition (RCCI) and Gasoline Compression Ignition (GCI) combustion are promising approaches to improve efficiency and reduce pollutant emissions. However, the benefits have generally been confined to mid-load operating conditions. To enable practical application, these approaches must be able to operate over the entire engine map. A particularly challenging area is high load, low speed operation. Accordingly, the present work uses detailed CFD modeling and engine experiments to compare RCCI and GCI combustion strategies at a high load, low speed condition. Computational optimizations of RCCI and GCI combustion were performed at 20 bar gross indicated mean effective pressure (IMEP) and 1300 rev/min. The optimum points from the two combustion strategies were verified using engine experiments and were used to make the comparisons between RCCI and GCI combustion. The comparison showed that both the strategies had very similar combustion characteristics with a near top dead center injection initiating combustion. A parametric study was performed to identify the key input parameters that control combustion for the RCCI and GCI strategies. For both strategies, the combustion phasing could be controlled by the start of injection (SOI) timing of the near TDC injection. The short ignition delay of diesel fuel gave the RCCI strategy better control over combustion than the GCI strategy, but also had a simultaneous tradeoff with soot emissions. With the GCI

  17. Components for more blue. BLUETEC takes away undesired nitrogen oxides and creates cleaner auto-ignition; Bausteine fuer mehr Blau. BLUETEC entfernt unerwuenschte Stickoxide und macht den Selbstzuender sauberer

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    The success story of the diesel engine is closely linked with the history of Mercedes-Benz. Now a new chapter is opened with BLUETEC. The modular technology package that is presented by Mercedes-Benz for the first time constitutes a milestone for cars with auto-ignition. BLUETEC enables to reduce the nitrogen oxide content considerably. The target is to build a diesel engine that is as clean as a gasoline engine. Thus DaimlerChrysler owns modern diesel drives, which are economical, powerful and at the same time the cleanest in the world. (orig.)

  18. Diagnosing and controlling mix in National Ignition Facility implosion experiments

    International Nuclear Information System (INIS)

    Hammel, B. A.; Scott, H. A.; Cerjan, C.; Clark, D. S.; Edwards, M. J.; Glenzer, S. H.; Haan, S. W.; Izumi, N.; Koch, J. A.; Landen, O. L.; Langer, S. H.; Smalyuk, V. A.; Suter, L. J.; Regan, S. P.; Epstein, R.; Kyrala, G. A.; Wilson, D. C.; Peterson, K.

    2011-01-01

    High mode number instability growth of ''isolated defects'' on the surfaces of National Ignition Facility [Moses et al., Phys. Plasmas 16, 041006 (2009)] capsules can be large enough for the perturbation to penetrate the imploding shell, and produce a jet of ablator material that enters the hot-spot. Since internal regions of the CH ablator are doped with Ge, mixing of this material into the hot-spot results in a clear signature of Ge K-shell emission. Evidence of jets entering the hot-spot has been recorded in x-ray images and spectra, consistent with simulation predictions [Hammel et al., High Energy Density Phys. 6, 171 (2010)]. Ignition targets have been designed to minimize instability growth, and capsule fabrication improvements are underway to reduce ''isolated defects.'' An experimental strategy has been developed where the final requirements for ignition targets can be adjusted through direct measurements of mix and experimental tuning.

  19. Engine Performance (Section C: Emission Control Systems). Auto Mechanics Curriculum Guide. Module 3. Instructor's Guide.

    Science.gov (United States)

    Rains, Larry

    This engine performance (emission control systems) module is one of a series of competency-based modules in the Missouri Auto Mechanics Curriculum Guide. Topics of this module's five units are: positive crankcase ventilation (PCV) and evaporative emission control systems; exhaust gas recirculation (EGR); air injection and catalytic converters;…

  20. DESIGN AND DEVELOPMENT OF AUTO DEPTH CONTROL OF REMOTELY OPERATED VEHICLE USING THRUSTER SYSTEM

    Directory of Open Access Journals (Sweden)

    F.A. Ali

    2014-12-01

    Full Text Available Remotely Operated Vehicles are underwater robots designed specifically for surveillance, monitoring and collecting data for underwater activities. In the underwater vehicle industries, the thruster is an important part in controlling the direction, depth and speed of the ROV. However, there are some ROVs that cannot be maintained at the specified depth for a long time because of disturbance. This paper proposes an auto depth control using a thruster system. A prototype of a thruster with an auto depth control is developed and attached to the previously fabricated UTeM ROV. This paper presents the operation of auto depth control as well as thrusters for submerging and emerging purposes and maintaining the specified depth. The thruster system utilizes a microcontroller as its brain, a piezoresistive strain gauge pressure sensor and a DC brushless motor to run the propeller. Performance analysis of the auto depth control system is conducted to identify the sensitivity of the pressure sensor, and the accuracy and stability of the system. The results show that the thruster system performs well in maintaining a specified depth as well as stabilizing itself when a disturbanceoccurs even with a simple proportional controller used to control the thruster, where the thruster is an important component of the ROV.

  1. Experimental investigations on controlled auto-ignition combustion in a four-stroke gasoline engine

    OpenAIRE

    Oakley, Aaron John

    2001-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. The effects of air and exhaust gas dilution on the CAI combustion of a range of fuels including three gasoline compositions, four primary reference fuels, and two alcohols are experimentally investigated using a single cylinder research engine. Two of the three gasolines tested are manufactured from standard gasoline during engine operation by a novel fuel system, designed to improve the per...

  2. 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... emission standards; enhanced evaporative emission controls for high performance sterndrive/inboard engines... requirement relating to the control of emissions from new nonroad engines which are used in construction...

  3. Laser-assisted homogeneous charge ignition in a constant volume combustion chamber

    Science.gov (United States)

    Srivastava, Dhananjay Kumar; Weinrotter, Martin; Kofler, Henrich; Agarwal, Avinash Kumar; Wintner, Ernst

    2009-06-01

    Homogeneous charge compression ignition (HCCI) is a very promising future combustion concept for internal combustion engines. There are several technical difficulties associated with this concept, and precisely controlling the start of auto-ignition is the most prominent of them. In this paper, a novel concept to control the start of auto-ignition is presented. The concept is based on the fact that most HCCI engines are operated with high exhaust gas recirculation (EGR) rates in order to slow-down the fast combustion processes. Recirculated exhaust gas contains combustion products including moisture, which has a relative peak of the absorption coefficient around 3 μm. These water molecules absorb the incident erbium laser radiations ( λ=2.79 μm) and get heated up to expedite ignition. In the present experimental work, auto-ignition conditions are locally attained in an experimental constant volume combustion chamber under simulated EGR conditions. Taking advantage of this feature, the time when the mixture is thought to "auto-ignite" could be adjusted/controlled by the laser pulse width optimisation, followed by its resonant absorption by water molecules present in recirculated exhaust gas.

  4. Investigation on the Effects of Internal EGR by Variable Exhaust Valve Actuation with Post Injection on Auto-ignited Combustion and Emission Performance

    Directory of Open Access Journals (Sweden)

    Insu Cho

    2018-04-01

    Full Text Available Variable valve mechanisms are usually applied to a gasoline combustion engine to improve its power performance by controlling the amount of intake air according to the operating load. These mechanisms offer one possibility of resolving the conflict of objectives between a further reduction of raw emissions and an improvement in fuel efficiency. In recent years, variable valve control systems have become extremely important in the diesel combustion engine. Importantly, it has been shown that there are several potential benefits of applying variable valve timing (VVT to a compression ignition engine. Valve train variability could offer one option to achieve the reduction goals of engine-out emissions and fuel consumption. The aim of this study was to investigate the effects on part load combustion and emission performance of internal exhaust gas recirculation (EGR by variable exhaust valve lift actuation using a cam-in-cam system, which is an electronically variable valve device with a variable inside cam retarded to about 30 degrees. Numerical simulation based on GT-POWER has been performed to predict the NOx reduction strategy at the part load operating point of 1200 rpm in a four-valve diesel engine. A GT-POWER model of a common-rail direct injection engine with internal EGR was built and verified with experimental data. As a result, large potential for reducing NOx emissions through the use of exhaust valve control has been identified. Namely, it is possible to utilize heat efficiently as recompression of retarded post injection with downscaled specification of the exhaust valve rather than the intake valve, even if the CIC V1 condition with a reduction of the exhaust valve has a higher internal EGR rate of about 2% compared to that of the CIC V2 condition.

  5. Model Development for Auto Spare Parts Inventory Control and ...

    African Journals Online (AJOL)

    2012-12-01

    Dec 1, 2012 ... essential motivating factors for providing control in manufacturing companies has never showed any sign ... The management of these parts can only be done with the aid of a computer; ... perform a discrete event simulation of.

  6. PID controller auto-tuning based on process step response and damping optimum criterion.

    Science.gov (United States)

    Pavković, Danijel; Polak, Siniša; Zorc, Davor

    2014-01-01

    This paper presents a novel method of PID controller tuning suitable for higher-order aperiodic processes and aimed at step response-based auto-tuning applications. The PID controller tuning is based on the identification of so-called n-th order lag (PTn) process model and application of damping optimum criterion, thus facilitating straightforward algebraic rules for the adjustment of both the closed-loop response speed and damping. The PTn model identification is based on the process step response, wherein the PTn model parameters are evaluated in a novel manner from the process step response equivalent dead-time and lag time constant. The effectiveness of the proposed PTn model parameter estimation procedure and the related damping optimum-based PID controller auto-tuning have been verified by means of extensive computer simulations. © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

  7. Closed loop auto control system software for Miniature Neutron Source Reactors (MNSRs)

    International Nuclear Information System (INIS)

    Iqbal, Masood; Qadir, Javed

    2009-01-01

    A closed loop auto control system has been developed and implemented at the Pakistan Research Reactor-2 (PARR-2). For interfacing of the site signals with a computer, a data acquisition card was employed. The system utilizes nine signals and, on their basis, carries out continuous on-line analysis, maintaining safe operation. On-line reactivity measurement is included in this software. Also, it generates control signals for keeping the reactor at the desired power level in auto-mode round-the-clock without human intervention. In case of abnormal conditions for either power or temperature or radiation level, alarms are initiated and if their levels reach beyond prescribed safe operation regime, automatic shutdown sequence is initiated. The control system has been thoroughly tested for various postulated scenarios. The test results have been in good agreement with the expected response. (orig.)

  8. Auto Code Generation for Simulink-Based Attitude Determination Control System

    Science.gov (United States)

    MolinaFraticelli, Jose Carlos

    2012-01-01

    This paper details the work done to auto generate C code from a Simulink-Based Attitude Determination Control System (ADCS) to be used in target platforms. NASA Marshall Engineers have developed an ADCS Simulink simulation to be used as a component for the flight software of a satellite. This generated code can be used for carrying out Hardware in the loop testing of components for a satellite in a convenient manner with easily tunable parameters. Due to the nature of the embedded hardware components such as microcontrollers, this simulation code cannot be used directly, as it is, on the target platform and must first be converted into C code; this process is known as auto code generation. In order to generate C code from this simulation; it must be modified to follow specific standards set in place by the auto code generation process. Some of these modifications include changing certain simulation models into their atomic representations which can bring new complications into the simulation. The execution order of these models can change based on these modifications. Great care must be taken in order to maintain a working simulation that can also be used for auto code generation. After modifying the ADCS simulation for the auto code generation process, it is shown that the difference between the output data of the former and that of the latter is between acceptable bounds. Thus, it can be said that the process is a success since all the output requirements are met. Based on these results, it can be argued that this generated C code can be effectively used by any desired platform as long as it follows the specific memory requirements established in the Simulink Model.

  9. Synthesis of SrCo {sub x} Ti {sub x} Fe{sub (12-2{sub x})}O{sub 19} through sol-gel auto-ignition and its characterisation

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Simon [Chemistry and Physics, Nottingham Trent University, Clifton Lane, Clifton, Nottingham, NG11 8NS (United Kingdom); Shirtcliffe, Neil J. [Chemistry and Physics, Nottingham Trent University, Clifton Lane, Clifton, Nottingham, NG11 8NS (United Kingdom)]. E-mail: neil.shirtcliffe@ntu.ac.uk; O' Keefe, Eoin S. [QinetiQ, Farnborough, Hampshire (United Kingdom); Appleton, Steve [QinetiQ, Farnborough, Hampshire (United Kingdom); Perry, Carole C. [Chemistry and Physics, Nottingham Trent University, Clifton Lane, Clifton, Nottingham, NG11 8NS (United Kingdom)]. E-mail: carole.perry@ntu.ac.uk

    2005-04-15

    Cobalt-titanium-doped strontium hexaferrites SrCo {sub x} Ti {sub x} Fe{sub (12-2{sub x})}O{sub 19} were synthesised via a sol-gel route using two different complexing agents (ethylene glycol and citric acid). Both routes led to quite pure undoped Sr ferrites, but the citric acid route formed purer doped materials. All synthesised materials consisted of particles smaller than 1 {mu}m, which is the size of a single magnetic domain, and various doping levels were achieved with the final elemental composition being within the bounds of experimental error. The materials synthesised using citric acid were compared with materials synthesised by a solid-state route using ferromagnetic resonance measurements and they were identical within experimental error. Citrate auto-ignition synthesis is more rapid and less prone to contamination than the standard solid-state method and doping levels can be easily varied between runs.

  10. Parking Space Detection and Trajectory Tracking Control for Vehicle Auto-Parking

    OpenAIRE

    Shiuh-Jer Huang; Yu-Sheng Hsu

    2017-01-01

    On-board available parking space detecting system, parking trajectory planning and tracking control mechanism are the key components of vehicle backward auto-parking system. Firstly, pair of ultrasonic sensors is installed on each side of vehicle body surface to detect the relative distance between ego-car and surrounding obstacle. The dimension of a found empty space can be calculated based on vehicle speed and the time history of ultrasonic sensor detecting information. This result can be u...

  11. Auto-Ignition of Iso-Stoichiometric Blends of Gasoline-Ethanol-Methanol (GEM) in SI, HCCI and CI Combustion Modes

    KAUST Repository

    Waqas, Muhammad

    2017-03-28

    Gasoline-ethanol-methanol (GEM) blends, with constant stoichiometric air-to-fuel ratio (iso-stoichiometric blending rule) and equivalent to binary gasoline-ethanol blends (E2, E5, E10 and E15 in % vol.), were defined to investigate the effect of methanol and combined mixtures of ethanol and methanol when blended with three FACE (Fuels for Advanced Combustion Engines) Gasolines, I, J and A corresponding to RON 70.2, 73.8 and 83.9, respectively, and their corresponding Primary Reference Fuels (PRFs). A Cooperative Fuel Research (CFR) engine was used under Spark Ignition and Homogeneous Charge Compression Ignited modes. An ignition quality tester was utilized in the Compression Ignition mode. One of the promising properties of GEM blends, which are derived using the iso-stoichiometric blending rule, is that they maintain a constant octane number, which has led to the introduction of methanol as a drop-in fuel to supplement bio-derived ethanol. A constant RON/HCCI fuel number/derived Research octane number property was observed in all three combustion modes for high RON fuels, but for low RON fuels, the iso-stoichiometric blending rule for constant octane number did not appear to be valid. The chemical composition and octane number of the base fuel also influenced the behavior of the GEM blends under different conditions.

  12. Auto-Ignition of Iso-Stoichiometric Blends of Gasoline-Ethanol-Methanol (GEM) in SI, HCCI and CI Combustion Modes

    KAUST Repository

    Waqas, Muhammad; Naser, Nimal; Sarathy, Mani; Feijs, Jeroen; Morganti, Kai; Nyrenstedt, Gustav; Johansson, Bengt

    2017-01-01

    Gasoline-ethanol-methanol (GEM) blends, with constant stoichiometric air-to-fuel ratio (iso-stoichiometric blending rule) and equivalent to binary gasoline-ethanol blends (E2, E5, E10 and E15 in % vol.), were defined to investigate the effect of methanol and combined mixtures of ethanol and methanol when blended with three FACE (Fuels for Advanced Combustion Engines) Gasolines, I, J and A corresponding to RON 70.2, 73.8 and 83.9, respectively, and their corresponding Primary Reference Fuels (PRFs). A Cooperative Fuel Research (CFR) engine was used under Spark Ignition and Homogeneous Charge Compression Ignited modes. An ignition quality tester was utilized in the Compression Ignition mode. One of the promising properties of GEM blends, which are derived using the iso-stoichiometric blending rule, is that they maintain a constant octane number, which has led to the introduction of methanol as a drop-in fuel to supplement bio-derived ethanol. A constant RON/HCCI fuel number/derived Research octane number property was observed in all three combustion modes for high RON fuels, but for low RON fuels, the iso-stoichiometric blending rule for constant octane number did not appear to be valid. The chemical composition and octane number of the base fuel also influenced the behavior of the GEM blends under different conditions.

  13. Distributed Fair Auto Rate Medium Access Control for IEEE 802.11 Based WLANs

    Science.gov (United States)

    Zhu, Yanfeng; Niu, Zhisheng

    Much research has shown that a carefully designed auto rate medium access control can utilize the underlying physical multi-rate capability to exploit the time-variation of the channel. In this paper, we develop a simple analytical model to elucidate the rule that maximizes the throughput of RTS/CTS based multi-rate wireless local area networks. Based on the discovered rule, we propose two distributed fair auto rate medium access control schemes called FARM and FARM+ from the view-point of throughput fairness and time-share fairness, respectively. With the proposed schemes, after receiving a RTS frame, the receiver selectively returns the CTS frame to inform the transmitter the maximum feasible rate probed by the signal-to-noise ratio of the received RTS frame. The key feature of the proposed schemes is that they are capable of maintaining throughput/time-share fairness in asymmetric situation where the distribution of SNR varies with stations. Extensive simulation results show that the proposed schemes outperform the existing throughput/time-share fair auto rate schemes in time-varying channel conditions.

  14. Design of power auto-regulating system's high reliability controller for 200 MW nuclear heating reactor

    International Nuclear Information System (INIS)

    An Zhencai; Liu Longzhi; Chen Yuan

    1996-01-01

    The paper mainly introduces power auto-regulating system's high reliability controller for 200 MW Nuclear Heating Reactor. The controller is implemented with excellent performance 16 bit single chip microcomputer 8097. Master controller and 10 digit samplers are blocked. Each and every block's hardware is identical. These blocks communicate each other through 8 bit BUS and operate synchronously by united clock and reset signal and are designed with three redundancies. The identity comparison principle through two-out-of three is also introduced. The test proves that designing scheme is feasible

  15. Computational characterization of ignition regimes in a syngas/air mixture with temperature fluctuations

    KAUST Repository

    Pal, Pinaki; Valorani, Mauro; Arias, Paul G.; Im, Hong G.; Wooldridge, Margaret S.; Ciottoli, Pietro P.; Galassi, Riccardo M.

    2016-01-01

    ) was applied to characterize the auto-ignition phenomena. All results supported that the observed ignition behaviors were consistent with the expected ignition regimes predicted by the theory of the regime diagram. This work provides new high-fidelity data

  16. Computer-controlled system for plasma ion energy auto-analyzer

    International Nuclear Information System (INIS)

    Wu Xianqiu; Chen Junfang; Jiang Zhenmei; Zhong Qinghua; Xiong Yuying; Wu Kaihua

    2003-01-01

    A computer-controlled system for plasma ion energy auto-analyzer was technically studied for rapid and online measurement of plasma ion energy distribution. The system intelligently controls all the equipments via a RS-232 port, a printer port and a home-built circuit. The software designed by LabVIEW G language automatically fulfils all of the tasks such as system initializing, adjustment of scanning-voltage, measurement of weak-current, data processing, graphic export, etc. By using the system, a few minutes are taken to acquire the whole ion energy distribution, which rapidly provide important parameters of plasma process techniques based on semiconductor devices and microelectronics

  17. The Signal Detection and Control Circuit Design for Confocal Auto-Focus System

    OpenAIRE

    Yin Liu; Jin Yu; Zeqiang Mo

    2016-01-01

    Based on the demands of Confocal Auto-Focus system, the implementation method of signal measurement circuit and control circuit is given. Using the high performance instrumental amplifier AD620BN, low noise precision FET Op amplifier AD795JRZ and ultralow offset voltage Op amplifier OP07EP, a signal measurement circuit used to converse the two differential light intensity signal to electric signal is designed. And a control circuit which takes MCU MSP430F149 as core processes the former signa...

  18. Engine Torque Control of Spark Ignition Engine using Fuzzy Gain Scheduling

    OpenAIRE

    Aris Triwiyatno

    2012-01-01

    In the spark ignition engine system, driver convenience is very dependent on satisfying engine torque appropriate with the throttle position given by the driver. Unfortunately, sometimes the fulfillment of engine torque is not in line with fuel saving efforts. This requires the development of high performance and robust power train controllers. One way to potentially meet these performance requirements is to introduce a method of controlling engine torque using fuzzy gain scheduling. By using...

  19. Fuel Saving Strategy in Spark Ignition Engine Using Fuzzy Logic Engine Torque Control

    OpenAIRE

    Aris Triwiyatno; Sumardi

    2012-01-01

    In the case of injection gasoline engine, or better known as spark ignition engines, an effort to improve engine performance as well as to reduce fuel consumption is a fairly complex problem. Generally, engine performance improvement efforts will lead to increase in fuel consumption. However, this problem can be solved by implementing engine torque control based on intelligent regulation such as the fuzzy logic inference system. In this study, fuzzy logic engine torque regulation is used to c...

  20. Functional Group Analysis for Diesel-like Mixing-Controlled Compression Ignition Combustion Blendstocks

    Energy Technology Data Exchange (ETDEWEB)

    Gaspar, Daniel J.; McCormick, Robert L.; Polikarpov, Evgueni; Fioroni, Gina; George, Anthe; Albrecht, Karl O.

    2016-12-30

    This report addresses the suitability of hydrocarbon and oxygenate functional groups for use as a diesel-like fuel blending component in an advanced, mixing-controlled, compression ignition combustion engine. The functional groups are chosen from those that could be derived from a biomass feedstock, and represent a full range of chemistries. This first systematic analysis of functional groups will be of value to all who are pursuing new bio-blendstocks for diesel-like fuels.

  1. Numerical Study of Natural Gas/Diesel Reactivity Controlled Compression Ignition Combustion with Large Eddy Simulation and Reynolds-Averaged Navier–Stokes Model

    Directory of Open Access Journals (Sweden)

    Amir-Hasan Kakaee

    2018-03-01

    Full Text Available In the current study, a comparative study is performed using Large Eddy Simulation (LES and Reynolds-averaged Navier–Stokes (RANS turbulence models on a natural gas/diesel Reactivity Controlled Compression Ignition (RCCI engine. The numerical results are validated against the available research work in the literature. The RNG (Re-Normalization Group k − ε and dynamic structure models are employed to model turbulent flow for RANS and LES simulations, respectively. Parameters like the premixed natural gas mass fraction, the second start of injection timing (SOI2 of diesel and the engine speed are studied to compare performance of RANS and LES models on combustion and pollutant emissions prediction. The results obtained showed that the LES and RANS model give almost similar predictions of cylinder pressure and heat release rate at lower natural gas mass fractions and late SOI2 timings. However, the LES showed improved capability to predict the natural gas auto-ignition and pollutant emissions prediction compared to RANS model especially at higher natural gas mass fractions.

  2. PC-based arc ignition and arc length control system for gas tungsten arc welding

    International Nuclear Information System (INIS)

    Liu, Y.; Cook, G.E.; Barnett, R.J.; Springfield, J.F.

    1992-01-01

    In this paper, a PC-based digital control system for gas tungsten arc welding (GTAW) is presented. This system controls the arc ignition process, the arc length, and the process of welding termination. A DT2818 made by Data Translation is used for interface and A/D and D/A conversions. The digital I/O ports of the DT2818 are used for control of wirefeed, shield gas, cooling water, welding power supply, etc. The DT2818 is housed in a PC. The welding signals and status are displayed on the screen for in-process monitoring. A user can control the welding process by the keyboard

  3. Target Diagnostic Control System Implementation for the National Ignition Facility

    International Nuclear Information System (INIS)

    Shelton, R.T.; Kamperschroer, J.H.; Lagin, L.J.; Nelson, J.R.; O'Brien, D.W.

    2010-01-01

    The extreme physics of targets shocked by NIF's 192-beam laser are observed by a diverse suite of diagnostics. Many diagnostics are being developed by collaborators at other sites, but ad hoc controls could lead to unreliable and costly operations. A Diagnostic Control System (DCS) framework for both hardware and software facilitates development and eases integration. Each complex diagnostic typically uses an ensemble of electronic instruments attached to sensors, digitizers, cameras, and other devices. In the DCS architecture each instrument is interfaced to a low-cost Windows XP processor and Java application. Each instrument is aggregated with others as needed in the supervisory system to form an integrated diagnostic. The Java framework provides data management, control services and operator GUI generation. DCS instruments are reusable by replication with reconfiguration for specific diagnostics in XML. Advantages include minimal application code, easy testing, and high reliability. Collaborators save costs by assembling diagnostics with existing DCS instruments. This talk discusses target diagnostic instrumentation used on NIF and presents the DCS architecture and framework.

  4. Software quality assurance plan for the National Ignition Facility integrated computer control system

    International Nuclear Information System (INIS)

    Woodruff, J.

    1996-11-01

    Quality achievement is the responsibility of the line organizations of the National Ignition Facility (NIF) Project. This Software Quality Assurance Plan (SQAP) applies to the activities of the Integrated Computer Control System (ICCS) organization and its subcontractors. The Plan describes the activities implemented by the ICCS section to achieve quality in the NIF Project's controls software and implements the NIF Quality Assurance Program Plan (QAPP, NIF-95-499, L-15958-2) and the Department of Energy's (DOE's) Order 5700.6C. This SQAP governs the quality affecting activities associated with developing and deploying all control system software during the life cycle of the NIF Project

  5. Auto Safety

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Auto Safety KidsHealth / For Parents / Auto Safety What's in this ... by teaching some basic rules. Importance of Child Safety Seats Using a child safety seat (car seat) ...

  6. Plans for the CIT [Compact Ignition Tokamak] instrumentation and control system

    International Nuclear Information System (INIS)

    Preckshot, G.G.

    1987-01-01

    Extensive experience with previous fusion experiments (TFTR, MFTF-B and others) is driving the design of the Instrumentation and Control System (I and C) for the Compact Ignition Tokamak (CIT) to be built at Princeton. The new design will reuse much equipment from TFTR and will be subdivided into six major parts: machine control, machine data acquisition, plasma diagnostic instrument control and instrument data acquisition, the database, shot sequencing and safety interlocks. In a major departure from previous fusion experiment control systems, the CIT machine control system will be a commercial process control system. Since the machine control system will be purchased as a completely functional product, we will be able to concentrate development manpower in plasma diagnostic instrument control, data acquisition, data processing and analysis, and database systems. We will discuss the issues driving the design, give a design overview and state the requirements upon any prospective commercial process control system

  7. Thermal re-ignition processes of switching arcs with various gas-blast using voltage application highly controlled by powersemiconductors

    Science.gov (United States)

    Nakano, Tomoyuki; Tanaka, Yasunori; Murai, K.; Uesugi, Y.; Ishijima, T.; Tomita, K.; Suzuki, K.; Shinkai, T.

    2018-05-01

    This paper focuses on a fundamental experimental approach to thermal arc re-ignition processes in a variety of gas flows in a nozzle. Using power semiconductor switches in the experimental system, the arc current and the voltage applied to the arc were controlled with precise timing. With this system, residual arcs were created in decaying phase under free recovery conditions; arc re-ignition was then intentionally instigated by application of artificial voltage—i.e. quasi-transient recovery voltage—to study the arc behaviour in both decaying and re-ignition phases. In this study, SF6, CO2, N2, O2, air and Ar arcs were intentionally re-ignited by quasi-TRV application at 20 μs delay time from initiation of free recovery condition. Through these experiments, the electron density at the nozzle throat was measured using a laser Thomson scattering method together with high speed video camera observation during the re-ignition process. Temporal variations in the electron density from the arc decaying to re-ignition phases were successfully obtained for each gas-blast arc at the nozzle throat. In addition, initial dielectric recovery properties of SF6, CO2, air and Ar arcs were measured under the same conditions. These data will be useful in the fundamental elucidation of thermal arc re-ignition processes.

  8. [Prevention of intrauterine adhesion with auto-crosslinked hyaluronic acid gel: a prospective, randomized, controlled clinical study].

    Science.gov (United States)

    Xiao, Songshu; Wan, Yajun; Zou, Fangjun; Ye, Mingzhu; Deng, Henan; Ma, Jiezhi; Wei, Yingying; Tan, Chen; Xue, Min

    2015-01-01

    To evaluate the efficacy and safety of auto-crosslinked hyaluronic acid (HA) gel for preventing intrauterine adhesion (IUA) after hysteroscopic adhesiolysis. A prospective, randomized, double blinded and controlled clinical trial (level I) was performed. According to American Fertility Society (AFS) scoring system, 120 patients (treatment group: 60 cases, control group: 60 cases) with moderate to severe IUA were enrolled. Upon completion of adhesiolysis, a Foley balloon catheter was first introduced into the uterine cavity and then 3 ml of auto-crosslinked HA gel for patients in the treatment group; patients in the control group, however, only received Foley balloon catheter. Second-look hysteroscopic examination was performed to all patients at 3 months postoperatively for evaluation of IUA. Primary endpoint was the reduction rate of IUA at 3 months after surgery. The secondary endpoints include total AFS score, score of each individual AFS category. At 3 months after surgery, auto-crosslinked HA gel resulted in significantly higher effective rate for reduction of adhesion, the effective rate were 76% (42/55) and 48% (27/56) respectively (P = 0.000 9); the total AFS score of treatment group was 2.1 ± 1.1, and significantly lower than that of control group (3.7 ± 2.5, P = 0.000 8). Application of auto-crosslinked HA gel after surgery significantly enhanced the improvement for each individual patient with regard to their adhesive type and menstrual pattern (P = 0.037 8, P = 0.000 4). The treatment group had significantly lower proportion of patients with moderate to severe adhesive stages than that of control group [13% (7/55) versus 38% (21/56), P = 0.000 6]. No adverse events and complications were observed. Auto-crosslinked HA gel coule be able to reduce IUA, decrease adhesion severity, and improve menopause postoperatively. This absorbable auto-crosslinked HA gel is proposed as a barrier for preventing IUA after intrauterine procedures.

  9. A novel auto-tuning PID control mechanism for nonlinear systems.

    Science.gov (United States)

    Cetin, Meric; Iplikci, Serdar

    2015-09-01

    In this paper, a novel Runge-Kutta (RK) discretization-based model-predictive auto-tuning proportional-integral-derivative controller (RK-PID) is introduced for the control of continuous-time nonlinear systems. The parameters of the PID controller are tuned using RK model of the system through prediction error-square minimization where the predicted information of tracking error provides an enhanced tuning of the parameters. Based on the model-predictive control (MPC) approach, the proposed mechanism provides necessary PID parameter adaptations while generating additive correction terms to assist the initially inadequate PID controller. Efficiency of the proposed mechanism has been tested on two experimental real-time systems: an unstable single-input single-output (SISO) nonlinear magnetic-levitation system and a nonlinear multi-input multi-output (MIMO) liquid-level system. RK-PID has been compared to standard PID, standard nonlinear MPC (NMPC), RK-MPC and conventional sliding-mode control (SMC) methods in terms of control performance, robustness, computational complexity and design issue. The proposed mechanism exhibits acceptable tuning and control performance with very small steady-state tracking errors, and provides very short settling time for parameter convergence. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  10. Control of combustion generated emissions from spark ignition engines: a review

    International Nuclear Information System (INIS)

    Mansha, M.; Shahid, E.M.; Qureshi, A.H.

    2012-01-01

    For the past several decades automobiles have been a major source of ground level emissions of various pollutants like CO, HC, NO/sub x/, SO/sub x/ CO/sub 2/, etc. Due to their dangerous effects on human health, vegetation and on climate, various pre combustion, in-cylinder and post. combustion techniques have been tried for their abatement. This paper reviews all of the workable measures taken so far to controlling the combustion generated emissions from 4-stroke Spark Ignition Vehicular Engines ever since the promulgation of emission control legislation/standards and their subsequent enforcement in the late 1960s. (author)

  11. Fractional order sliding-mode control based on parameters auto-tuning for velocity control of permanent magnet synchronous motor.

    Science.gov (United States)

    Zhang, BiTao; Pi, YouGuo; Luo, Ying

    2012-09-01

    A fractional order sliding mode control (FROSMC) scheme based on parameters auto-tuning for the velocity control of permanent magnet synchronous motor (PMSM) is proposed in this paper. The control law of the proposed F(R)OSMC scheme is designed according to Lyapunov stability theorem. Based on the property of transferring energy with adjustable type in F(R)OSMC, this paper analyzes the chattering phenomenon in classic sliding mode control (SMC) is attenuated with F(R)OSMC system. A fuzzy logic inference scheme (FLIS) is utilized to obtain the gain of switching control. Simulations and experiments demonstrate that the proposed FROSMC not only achieve better control performance with smaller chatting than that with integer order sliding mode control, but also is robust to external load disturbance and parameter variations. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

  12. Control System For Cryogenic THD Layering At The National Ignition Facility

    International Nuclear Information System (INIS)

    Fedorov, M.; Blubaugh, J.; Edwards, O.; Mauvais, M.; Sanchez, R.; Wilson, B.

    2011-01-01

    The National Ignition Facility (NIF) is the world largest and most energetic laser system for Inertial Confinement Fusion (ICF). In 2010, NIF began ignition experiments using cryogenically cooled targets containing layers of the tritium-hydrogen-deuterium (THD) fuel. The 75 (micro)m thick layer is formed inside of the 2 mm target capsule at temperatures of approximately 18 K. The ICF target designs require sub-micron smoothness of the THD ice layers. Formation of such layers is still an active research area, requiring a flexible control system capable of executing the evolving layering protocols. This task is performed by the Cryogenic Target Subsystem (CTS) of the NIF Integrated Computer Control System (ICCS). The CTS provides cryogenic temperature control with the 1 mK resolution required for beta-layering and for the thermal gradient fill of the capsule. The CTS also includes a 3-axis x-ray radiography engine for phase contrast imaging of the ice layers inside of the plastic and beryllium capsules. In addition to automatic control engines, CTS is integrated with the Matlab interactive programming environment to allow flexibility in experimental layering protocols. The CTS Layering Matlab Toolbox provides the tools for layer image analysis, system characterization and cryogenic control. The CTS Layering Report tool generates qualification metrics of the layers, such as concentricity of the layer and roughness of the growth boundary grooves. The CTS activities are automatically coordinated with other NIF controls in the carefully orchestrated NIF Shot Sequence.

  13. MPC-based auto-tuned PID controller for the steam generator water level

    International Nuclear Information System (INIS)

    Na, Man Gyun

    2001-01-01

    In this work, proportional-integral-derivative (PID) control gains are automatically tuned by using a model predictive control (MPC) method. The MPC has received much attention as a powerful tool for the control of industrial process systems. An MPC-based PID controller can be derived from the second order linear model of a process. The steam generator is usually described by the well-known 4 th order linear model which consists of the mass capacity, reverse dynamics and mechanical oscillations terms. But the important terms in this linear model are the mass capacity and reverse dynamics terms, both of which can be described by a 2 nd order linear system. The proposed auto-tuned PID controller was applied to a linear model of steam generators. The parameters of a linear model for steam generators are very different according to the power levels. The proposed controller showed good performance for the water level deviation and sudden steam flow disturbances that are typical in the existing power plants by changing only the input-weighting factor according to the power level

  14. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zhi, E-mail: wangzhi@tsinghua.edu.c [State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084 (China); He Xu; Wang Jianxin; Shuai Shijin; Xu Fan; Yang Dongbo [State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084 (China)

    2010-05-15

    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{sub x} emission and high thermal efficiency. The SICI combustion mode can be applied in medium-high load region for high efficiency gasoline engines.

  16. On-line Auto-Tuning of PI Control of the Superheat for a Supermarket Refrigeration System

    DEFF Research Database (Denmark)

    Yang, Zhenyu; Andersen, Casper; Izadi-Zamanabadi, Roozbeh

    2011-01-01

    An online PI auto-tuning method is proposed for superheat control for a type of supermarket refrigeration systems. The proposed procedure consists of three serial steps: Step-One uses one of the two proposed empirical methods, namely multi-step method and relay method, for modeling initialization...

  17. Software solutions manage the definition, operation, maintenance and configuration control of the National Ignition Facility

    International Nuclear Information System (INIS)

    Dobson, D.; Churby, A.; Krieger, E.; Maloy, D.; White, K.

    2011-01-01

    The National Ignition Facility (NIF) is the world's largest laser composed of millions of individual parts brought together to form one massive assembly. Maintaining control of the physical definition, status and configuration of this structure is a monumental undertaking yet critical to the validity of the shot experiment data and the safe operation of the facility. The NIF business application suite of software provides the means to effectively manage the definition, build, operation, maintenance and configuration control of all components of the National Ignition Facility. State of the art Computer Aided Design software applications are used to generate a virtual model and assemblies. Engineering bills of material are controlled through the Enterprise Configuration Management System. This data structure is passed to the Enterprise Resource Planning system to create a manufacturing bill of material. Specific parts are serialized then tracked along their entire lifecycle providing visibility to the location and status of optical, target and diagnostic components that are key to assessing pre-shot machine readiness. Nearly forty thousand items requiring preventive, reactive and calibration maintenance are tracked through the System Maintenance and Reliability Tracking application to ensure proper operation. Radiological tracking applications ensure proper stewardship of radiological and hazardous materials and help provide a safe working environment for NIF personnel.

  18. Software solutions manage the definition, operation, maintenance and configuration control of the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Dobson, D; Churby, A; Krieger, E; Maloy, D; White, K

    2011-07-25

    The National Ignition Facility (NIF) is the world's largest laser composed of millions of individual parts brought together to form one massive assembly. Maintaining control of the physical definition, status and configuration of this structure is a monumental undertaking yet critical to the validity of the shot experiment data and the safe operation of the facility. The NIF business application suite of software provides the means to effectively manage the definition, build, operation, maintenance and configuration control of all components of the National Ignition Facility. State of the art Computer Aided Design software applications are used to generate a virtual model and assemblies. Engineering bills of material are controlled through the Enterprise Configuration Management System. This data structure is passed to the Enterprise Resource Planning system to create a manufacturing bill of material. Specific parts are serialized then tracked along their entire lifecycle providing visibility to the location and status of optical, target and diagnostic components that are key to assessing pre-shot machine readiness. Nearly forty thousand items requiring preventive, reactive and calibration maintenance are tracked through the System Maintenance & Reliability Tracking application to ensure proper operation. Radiological tracking applications ensure proper stewardship of radiological and hazardous materials and help provide a safe working environment for NIF personnel.

  19. Controllable frequency entanglement via auto-phase-matched spontaneous parametric down-conversion

    International Nuclear Information System (INIS)

    Sergienko, A.V.; Walton, Z.D.; Booth, M.C.; Saleh, B.E.A.; Teich, M.C.

    2005-01-01

    Full text: A new method for generating entangled photons with controllable frequency correlation via spontaneous parametric down-conversion (SPDC) is presented. The method entails initiating counter-propagating SPDC in a single-mode nonlinear waveguide by pumping with a pulsed beam perpendicular to the waveguide. In a typical spontaneous parametric down-conversion (SPDC) experiment, a photon from a monochromatic pump beam decays into two photons (often referred to as signal and idler) via interaction with a nonlinear optical crystal. While the signal and idler may be broadband individually, conservation of energy requires that the sum of their respective frequencies equals the single frequency of the monochromatic pump. This engenders frequency anti-correlation in the down-converted beams. Two developments in quantum information theory have renewed interest in the generalized states of frequency correlation. First, quantum information processes requiring the synchronized creation of multiple photon pairs have been devised, such as quantum teleportation. The requisite temporal control can be achieved by pumping the crystal with a brief pulse. The availability of pump photons of differing frequencies relaxes the strict frequency anti-correlation in the down-converted beams. Second, applications such as entanglement-enhanced clock synchronization and one-way auto-compensating quantum cryptography have been introduced that specifically require frequency correlation, as opposed to the usual frequency anticorrelation. Our method for obtaining controllable frequency entanglement entails initiating type-I SPDC (signal and idler identically polarized) in a single-mode nonlinear waveguide by pumping with a pulsed beam perpendicular to the waveguide. The down-converted photons emerge from opposite ends of the waveguide with a joint spectrum that can be varied from frequency anti-correlated to frequency correlated by adjusting the temporal and spatial characteristics of the

  20. Use of the target diagnostic control system in the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Shelton, R; Lagin, L; Nelson, J

    2011-07-25

    The extreme physics of targets shocked by NIF's 192-beam laser are observed by a diverse suite of diagnostics including optical backscatter, time-integrated, time resolved and gated X-ray sensors, laser velocity interferometry, and neutron time of flight. Diagnostics to diagnose fusion ignition implosion and neutron emissions have been developed. A Diagnostic Control System (DCS) for both hardware and software facilitates development and eases integration. Each complex diagnostic typically uses an ensemble of electronic instruments attached to sensors, digitizers, cameras, and other devices. In the DCS architecture each instrument is interfaced to a low-cost Window XP processor and Java application. Instruments are aggregated as needed in the supervisory system to form an integrated diagnostic. The Java framework provides data management, control services and operator GUI generation. During the past several years, over thirty-six diagnostics have been deployed using this architecture in support of the National Ignition Campaign (NIC). The DCS architecture facilitates the expected additions and upgrades to diagnostics as more experiments are performed. This paper presents the DCS architecture, framework and our experiences in using it during the NIC to operate, upgrade and maintain a large set of diagnostic instruments.

  1. Use of the target diagnostic control system in the National Ignition Facility

    International Nuclear Information System (INIS)

    Shelton, R.; Lagin, L.; Nelson, J.

    2011-01-01

    The extreme physics of targets shocked by NIF's 192-beam laser are observed by a diverse suite of diagnostics including optical backscatter, time-integrated, time resolved and gated X-ray sensors, laser velocity interferometry, and neutron time of flight. Diagnostics to diagnose fusion ignition implosion and neutron emissions have been developed. A Diagnostic Control System (DCS) for both hardware and software facilitates development and eases integration. Each complex diagnostic typically uses an ensemble of electronic instruments attached to sensors, digitizers, cameras, and other devices. In the DCS architecture each instrument is interfaced to a low-cost Window XP processor and Java application. Instruments are aggregated as needed in the supervisory system to form an integrated diagnostic. The Java framework provides data management, control services and operator GUI generation. During the past several years, over thirty-six diagnostics have been deployed using this architecture in support of the National Ignition Campaign (NIC). The DCS architecture facilitates the expected additions and upgrades to diagnostics as more experiments are performed. This paper presents the DCS architecture, framework and our experiences in using it during the NIC to operate, upgrade and maintain a large set of diagnostic instruments.

  2. PID-controller with predictor and auto-tuning algorithm: study of efficiency for thermal plants

    Science.gov (United States)

    Kuzishchin, V. F.; Merzlikina, E. I.; Hoang, Van Va

    2017-09-01

    The problem of efficiency estimation of an automatic control system (ACS) with a Smith predictor and PID-algorithm for thermal plants is considered. In order to use the predictor, it is proposed to include an auto-tuning module (ATC) into the controller; the module calculates parameters for a second-order plant module with a time delay. The study was conducted using programmable logical controllers (PLC), one of which performed control, ATC, and predictor functions. A simulation model was used as a control plant, and there were two variants of the model: one of them was built on the basis of a separate PLC, and the other was a physical model of a thermal plant in the form of an electrical heater. Analysis of the efficiency of the ACS with the predictor was carried out for several variants of the second order plant model with time delay, and the analysis was performed on the basis of the comparison of transient processes in the system when the set point was changed and when a disturbance influenced the control plant. The recommendations are given on correction of the PID-algorithm parameters when the predictor is used by means of using the correcting coefficient k for the PID parameters. It is shown that, when the set point is changed, the use of the predictor is effective taking into account the parameters correction with k = 2. When the disturbances influence the plant, the use of the predictor is doubtful, because the transient process is too long. The reason for this is that, in the neighborhood of the zero frequency, the amplitude-frequency characteristic (AFC) of the system with the predictor has an ascent in comparison with the AFC of the system without the predictor.

  3. Software quality assurance plan for the National Ignition Facility integrated computer control system

    Energy Technology Data Exchange (ETDEWEB)

    Woodruff, J.

    1996-11-01

    Quality achievement is the responsibility of the line organizations of the National Ignition Facility (NIF) Project. This Software Quality Assurance Plan (SQAP) applies to the activities of the Integrated Computer Control System (ICCS) organization and its subcontractors. The Plan describes the activities implemented by the ICCS section to achieve quality in the NIF Project`s controls software and implements the NIF Quality Assurance Program Plan (QAPP, NIF-95-499, L-15958-2) and the Department of Energy`s (DOE`s) Order 5700.6C. This SQAP governs the quality affecting activities associated with developing and deploying all control system software during the life cycle of the NIF Project.

  4. A Study on Homogeneous Charge Compression Ignition Gasoline Engines

    Science.gov (United States)

    Kaneko, Makoto; Morikawa, Koji; Itoh, Jin; Saishu, Youhei

    A new engine concept consisting of HCCI combustion for low and midrange loads and spark ignition combustion for high loads was introduced. The timing of the intake valve closing was adjusted to alter the negative valve overlap and effective compression ratio to provide suitable HCCI conditions. The effect of mixture formation on auto-ignition was also investigated using a direct injection engine. As a result, HCCI combustion was achieved with a relatively low compression ratio when the intake air was heated by internal EGR. The resulting combustion was at a high thermal efficiency, comparable to that of modern diesel engines, and produced almost no NOx emissions or smoke. The mixture stratification increased the local A/F concentration, resulting in higher reactivity. A wide range of combustible A/F ratios was used to control the compression ignition timing. Photographs showed that the flame filled the entire chamber during combustion, reducing both emissions and fuel consumption.

  5. The Overview of the National Ignition Facility Distributed Computer Control System

    International Nuclear Information System (INIS)

    Lagin, L.J.; Bettenhausen, R.C.; Carey, R.A.; Estes, C.M.; Fisher, J.M.; Krammen, J.E.; Reed, R.K.; VanArsdall, P.J.; Woodruff, J.P.

    2001-01-01

    The Integrated Computer Control System (ICCS) for the National Ignition Facility (NIF) is a layered architecture of 300 front-end processors (FEP) coordinated by supervisor subsystems including automatic beam alignment and wavefront control, laser and target diagnostics, pulse power, and shot control timed to 30 ps. FEP computers incorporate either VxWorks on PowerPC or Solaris on UltraSPARC processors that interface to over 45,000 control points attached to VME-bus or PCI-bus crates respectively. Typical devices are stepping motors, transient digitizers, calorimeters, and photodiodes. The front-end layer is divided into another segment comprised of an additional 14,000 control points for industrial controls including vacuum, argon, synthetic air, and safety interlocks implemented with Allen-Bradley programmable logic controllers (PLCs). The computer network is augmented asynchronous transfer mode (ATM) that delivers video streams from 500 sensor cameras monitoring the 192 laser beams to operator workstations. Software is based on an object-oriented framework using CORBA distribution that incorporates services for archiving, machine configuration, graphical user interface, monitoring, event logging, scripting, alert management, and access control. Software coding using a mixed language environment of Ada95 and Java is one-third complete at over 300 thousand source lines. Control system installation is currently under way for the first 8 beams, with project completion scheduled for 2008

  6. National Ignition Facility TestController for automated and manual testing

    Energy Technology Data Exchange (ETDEWEB)

    Zielinski, Jason, E-mail: fishler2@llnl.gov [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States)

    2012-12-15

    The Controls and Information Systems (CIS) organization for the National Ignition Facility (NIF) has developed controls, configuration and analysis software applications that combine for several million lines of code. The team delivers updates throughout the year, from major releases containing hundreds of changes to patch releases containing a small number of focused updates. To ensure the quality of each delivery, manual and automated tests are performed using the NIF TestController test infrastructure. The TestController system provides test inventory management, test planning, automated and manual test execution, release testing summaries and results search, all through a web browser interface. As part of the three-stage software testing strategy, the NIF TestController system helps plan, evaluate and track the readiness of each release to the NIF production environment. After several years of use in testing NIF software applications, the TestController's manual testing features have been leveraged for verifying the installation and operation of NIF Target Diagnostic hardware. The TestController recorded its first test results in 2004. Today, the system has recorded the execution of more than 160,000 tests and continues to play a central role in ensuring that NIF hardware and software meet the requirements of a high reliability facility. This paper describes the TestController system and discusses its use in assuring the quality of software delivered to the NIF.

  7. National Ignition Facility TestController for automated and manual testing

    International Nuclear Information System (INIS)

    Zielinski, Jason

    2012-01-01

    The Controls and Information Systems (CIS) organization for the National Ignition Facility (NIF) has developed controls, configuration and analysis software applications that combine for several million lines of code. The team delivers updates throughout the year, from major releases containing hundreds of changes to patch releases containing a small number of focused updates. To ensure the quality of each delivery, manual and automated tests are performed using the NIF TestController test infrastructure. The TestController system provides test inventory management, test planning, automated and manual test execution, release testing summaries and results search, all through a web browser interface. As part of the three-stage software testing strategy, the NIF TestController system helps plan, evaluate and track the readiness of each release to the NIF production environment. After several years of use in testing NIF software applications, the TestController's manual testing features have been leveraged for verifying the installation and operation of NIF Target Diagnostic hardware. The TestController recorded its first test results in 2004. Today, the system has recorded the execution of more than 160,000 tests and continues to play a central role in ensuring that NIF hardware and software meet the requirements of a high reliability facility. This paper describes the TestController system and discusses its use in assuring the quality of software delivered to the NIF.

  8. The use of CO 2 as an additive for ignition delay and pollutant control in CH 4 /air autoignition

    KAUST Repository

    Tingas, Efstathios Al.

    2017-10-05

    The effect of CO2 dilution on the adiabatic and isochoric autoignition of CH4/air mixtures is analyzed with Computational Singular Perturbation (CSP) algorithmic tools, with a particular emphasis on the determination of the features of the chemical dynamics that control ignition delay and emission formation. Increasing CO2 dilution causes longer ignition delays, lower final temperatures and decreased formation of NO and CO. These effects of CO2 dilution are shown to be entirely thermal, contrary to what happens with dilution with H2O, which also has chemical activity and can reduce ignition delay. For the same initial mole fraction of the diluent, the decrease in final temperature and in NO concentration is larger in the CO2 case whereas the decrease in CO is larger in the H2O case. The thermal effect of CO2 is entirely analogous with those of dilution with the chemically inert Ar, only stronger for the same percentage of initial dilution, because of the larger specific heat of CO2. The reactions that have the largest contribution to the characteristic explosive time scale of the system during ignition delay (H2O2(+M)→OH+OH(+M), CH3O2+CH2O→CH3O2H+HCO, CH4+CH3O2→CH3+CH3O2H, H+O2→O+OH, etc.) are not substantially affected by CO2 dilution, neither are the species that are pointed by CSP (CH3O2, H2O2, CH2O, etc.) as having the largest impact on the this timescale. The same holds for the modes that control CO and NO formation. The results point to the possibility of cold exhaust gas recirculation being used in order to produce mixtures with longer ignition delays and therefore substantial resistance to uncontrolled ignition.

  9. Application of Auto CAD

    International Nuclear Information System (INIS)

    Park, Yong Un; Kim, Geun Ho

    1989-05-01

    This book has introduction to use this book and explanation of application on Auto CAD, which includes, sub directories, batch files, robot wrist, design of standard paper, title block, robort weld room, robert wrist joint, PC board, plant sym, electro, PID, machines, robots, bubbles, plant, schema, Pid, plant assembly, robots, dim plant, PL-ASSM, plotting line weight control, symbol drawing joint, Auto CAD using script file, set up of workout · MNU, workout MNU, ACAD, LSP and workout · MNU.

  10. 76 FR 25246 - Control of Emissions From New and In-Use Marine Compression-Ignition Engines and Vessels; CFR...

    Science.gov (United States)

    2011-05-04

    ... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 1042 Control of Emissions From New and In-Use Marine Compression- Ignition Engines and Vessels; CFR Correction Correction In rule document 2011-8794 appearing on pages 20550-20551 in the issue of Wednesday, April 13, 2011, make the following correction: Sec. 1042...

  11. 76 FR 26620 - Control of Emissions From New and In-Use Marine Compression-Ignition Engines and Vessels; CFR...

    Science.gov (United States)

    2011-05-09

    ... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 1042 Control of Emissions From New and In-Use Marine Compression- Ignition Engines and Vessels; CFR Correction Correction In rule correction document C1-2011-8794 appearing on page 25246 in the issue of Wednesday, May 4, 2011, make the following correction: Sec. 1042.901...

  12. 76 FR 20550 - Control of Emissions From New and In-Use Marine Compression-Ignition Engines and Vessels

    Science.gov (United States)

    2011-04-13

    ... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 1042 Control of Emissions From New and In-Use Marine Compression- Ignition Engines and Vessels CFR Correction In Title 40 of the Code of Federal Regulations, Part... service, whichever comes first. (2) For vessels with no Category 3 engines, a vessel that has been...

  13. 75 FR 37310 - Control of Emissions From New and In-Use Nonroad Compression-Ignition Engines

    Science.gov (United States)

    2010-06-29

    ... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 1039 Control of Emissions From New and In-Use Nonroad Compression- Ignition Engines CFR Correction In Title 40 of the Code of Federal Regulations, Part 1000 to End... for my engines in model year 2014 and earlier? * * * * * Table 2 of Sec. 1039.102--Interim Tier 4...

  14. Influence of several factors on ignition lag in a compression-ignition engine

    Science.gov (United States)

    Gerrish, Harold C; Voss, Fred

    1932-01-01

    This investigation was made to determine the influence of fuel quality, injection advance angle, injection valve-opening pressure, inlet-air pressure, compression ratio, and engine speed on the time lag of auto-ignition of a Diesel fuel oil in a single-cylinder compression-ignition engine as obtained from an analysis of indicator diagrams. Three cam-operated fuel-injection pumps, two pumps cams, and an automatic injection valve with two different nozzles were used. Ignition lag was considered to be the interval between the start of injection of the fuel as determined with a Stroborama and the start of effective combustion as determined from the indicator diagram, the latter being the point where 4.0 x 10(exp-6) pound of fuel had been effectively burned. For this particular engine and fuel it was found that: (1) for a constant start and the same rate of fuel injection up the point of cut-off, a variation in fuel quantity from 1.2 x 10(exp-4) to 4.1 x 10(exp-4) pound per cycle has no appreciable effect on the ignition lag; (2) injection advance angle increases or decreases the lag according to whether density, temperature, or turbulence has the controlling influence; (3) increase in valve-opening pressure slightly increases the lag; and (4) increase of inlet-air pressure, compression ratio, and engine speed reduces the lag.

  15. Software solutions manage the definition, operation, maintenance and configuration control of the National Ignition Facility

    International Nuclear Information System (INIS)

    Dobson, Darwin; Churby, Al; Krieger, Ed; Maloy, Donna; White, Kevin

    2012-01-01

    Highlights: ► NIF is a complex experimental facility composed of ∼4 million components. ► We describe business tools to define, build, operate, and maintain all components. ► CAD tools generate virtual models and assemblies under configuration control. ► Items requiring preventive, reactive, and/or calibration maintenance are tracked. ► Radiological or hazardous materials undergo additional controls. - Abstract: The National Ignition Facility (NIF) is the world's largest laser composed of millions of individual parts brought together to form one massive assembly. Maintaining control of the physical definition, status and configuration of this structure is a monumental undertaking yet critical to the validity of experimental data and the safe operation of the facility. A major programmatic challenge is to deploy software solutions to effectively manage the definition, build, operation, and maintenance, and configuration control of all components of NIF. The strategy for meeting this challenge involves deploying and integrating an enterprise application suite of solutions consisting of both Commercial-Off-The-Shelf (COTS) products and custom developed software.This paper describes how this strategy has been implemented along with a discussion on the successes realized and the ongoing challenges associated with this approach.

  16. Reducing methods of patients exposed dose using auto exposure control system in digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Seong Gyu [Dept. of Diagnostic Radiology, Dong A University Medical Center, Busan (Korea, Republic of)

    2013-06-15

    This study was carried out to reduce patient dose through focus-detector distance, kilovoltage, and a combination of copper filters. In the C, L-spine lateral, Skull AP views were obtained by making changes of 60-100 kV in tube voltage and of 100-200 cm in focus-detector distance and by adding a copper filter when using an auto exposure control device in the digital radiography equipment. The incident dose showed 90 kV, 0.3 mmCu in C-spine lateral with 0.06 mGy under the condition of 200 cm; 100 kV, 0.3 mmCu with 0.40 mGy under the condition of 200 cm and 90 kV 0.3 mmCu in Skull AP with the lowest value of 0.24 mGy under the condition of 140 cm. It was observed that entrance surface dose decreased the most when was increased by 150 cm, 70 kV (C-spine lateral), 81 kV (L-spine lateral). It was also found out that as the between the focus-detector increased in the expansion of the video decreased but the difference was not significant when the distance was 180 cm or more. Skull AP showed the most reduction in the entrance surface dose when the tube voltage was changed by 80 kV, 0.1 mmCu, and 120 cm. Therefore, when using the automatic exposure control device, it is recommended to use the highest tube voltage if possible and to increase focus-detector distance at least by 150-200 cm in wall and 120-140 cm in table in consideration of the radiotechnologist's physical conditions, and to combine 0.1-0.3 mmCu and higher filters. It is thus expected to reduce patient dose by avoiding distortion of images and reducing the entrance surface dose.

  17. Program auto

    International Nuclear Information System (INIS)

    Rawool-Sullivan, M.W.; Plagnol, E.

    1990-01-01

    The program AUTO was developed to be used in the analysis of dE vs E type spectra. This program is written in FORTRAN and calculates dE vs E lines in MeV. The provision is also made in the program to convert these lines from MeV to ADC channel numbers to facilitate the comparison with the raw data from the experiments. Currently the output of this program can be plotted with the display program, called VISU, but it can also be used independent of the program VISU, with little or no modification in the actual fortran code. The program AUTO has many useful applications. In this article the program AUTO is described along with its applications

  18. The influence of beam energy, mode and focal length on the control of laser ignition in an internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Mullett, J D [Laser Group, Department of Engineering, University of Liverpool, Brownlow Street, Liverpool, L69 3GH (United Kingdom); Dodd, R [Laser Group, Department of Engineering, University of Liverpool, Brownlow Street, Liverpool, L69 3GH (United Kingdom); Williams, C J [Laser Group, Department of Engineering, University of Liverpool, Brownlow Street, Liverpool, L69 3GH (United Kingdom); Triantos, G [Powertrain Control Group, Department of Engineering, University of Liverpool, Brownlow Street, Liverpool, L69 3GH (United Kingdom); Dearden, G [Laser Group, Department of Engineering, University of Liverpool, Brownlow Street, Liverpool, L69 3GH (United Kingdom); Shenton, A T [Powertrain Control Group, Department of Engineering, University of Liverpool, Brownlow Street, Liverpool, L69 3GH (United Kingdom); Watkins, K G [Laser Group, Department of Engineering, University of Liverpool, Brownlow Street, Liverpool, L69 3GH (United Kingdom); Carroll, S D [Ford Motor Company, Dunton Research and Engineering Centre, Laindon, Basildon, Essex, SS15 6EE (United Kingdom); Scarisbrick, A D [Ford Motor Company, Dunton Research and Engineering Centre, Laindon, Basildon, Essex, SS15 6EE (United Kingdom); Keen, S [GSI Group, Cosford Lane, Swift Valley, Rugby, Warwickshire, CV21 1QN (United Kingdom)

    2007-08-07

    This work involves a study on laser ignition (LI) in an internal combustion (IC) engine and investigates the effects on control of engine combustion performance and stability of varying specific laser parameters (beam energy, beam quality, minimum beam waist size, focal point volume and focal length). A Q-switched Nd : YAG laser operating at the fundamental wavelength 1064 nm was successfully used to ignite homogeneous stoichiometric gasoline and air mixtures in one cylinder of a 1.6 litre IC test engine, where the remaining three cylinders used conventional electrical spark ignition (SI). A direct comparison between LI and conventional SI is presented in terms of changes in coefficient of variability in indicated mean effective pressure (COV{sub IMEP}) and the variance in the peak cylinder pressure position (Var{sub PPP}). The laser was individually operated in three different modes by changing the diameter of the cavity aperture, where the results show that for specific parameters, LI performed better than SI in terms of combustion performance and stability. Minimum ignition energies for misfire free combustion ranging from 4 to 28 mJ were obtained for various optical and laser configurations and were compared with the equivalent minimum optical breakdown energies in air.

  19. The influence of beam energy, mode and focal length on the control of laser ignition in an internal combustion engine

    International Nuclear Information System (INIS)

    Mullett, J D; Dodd, R; Williams, C J; Triantos, G; Dearden, G; Shenton, A T; Watkins, K G; Carroll, S D; Scarisbrick, A D; Keen, S

    2007-01-01

    This work involves a study on laser ignition (LI) in an internal combustion (IC) engine and investigates the effects on control of engine combustion performance and stability of varying specific laser parameters (beam energy, beam quality, minimum beam waist size, focal point volume and focal length). A Q-switched Nd : YAG laser operating at the fundamental wavelength 1064 nm was successfully used to ignite homogeneous stoichiometric gasoline and air mixtures in one cylinder of a 1.6 litre IC test engine, where the remaining three cylinders used conventional electrical spark ignition (SI). A direct comparison between LI and conventional SI is presented in terms of changes in coefficient of variability in indicated mean effective pressure (COV IMEP ) and the variance in the peak cylinder pressure position (Var PPP ). The laser was individually operated in three different modes by changing the diameter of the cavity aperture, where the results show that for specific parameters, LI performed better than SI in terms of combustion performance and stability. Minimum ignition energies for misfire free combustion ranging from 4 to 28 mJ were obtained for various optical and laser configurations and were compared with the equivalent minimum optical breakdown energies in air

  20. Target Diagnostic Instrument-Based Controls Framework for the National Ignition Facility

    International Nuclear Information System (INIS)

    Shelton, R; O'Brien, D; Nelson, J; Kamperschroer, J

    2007-01-01

    NIF target diagnostics are being developed to observe and measure the extreme physics of targets irradiated by the 192-beam laser. The response time of target materials can be on the order of 100ps--the time it takes light to travel 3 cm--temperatures more than 100 times hotter than the surface of the sun, and pressures that exceed 109 atmospheres. Optical and x-ray diagnostics were developed and fielded to observe and record the results of the first 4-beam experiments at NIF. Hard and soft x-ray spectra were measured, and time-integrated and gated x-ray images of hydrodynamics experiments were recorded. Optical diagnostics recorded backscatter from the target, and VISAR laser velocimetry measurements were taken of laser-shocked target surfaces. Additional diagnostics are being developed and commissioned to observe and diagnose ignition implosions, including various neutron and activation diagnostics. NIF's diagnostics are being developed at LLNL and with collaborators at other sites. To accommodate the growing number of target diagnostics, an Instrument-Based Controls hardware-software framework has been developed to facilitate development and ease integration into the NIF Integrated Computer Control System (ICCS). Individual WindowsXP PC controllers for each digitizer, power supply and camera (i.e., instruments) execute controls software unique to each instrument model. Each hardware-software controller manages a single instrument, in contrast to the complexity of combining all the controls software needed for a diagnostic into a single controller. Because of this simplification, controllers can be more easily tested on the actual hardware, evaluating all normal and off-normal conditions. Each target diagnostic is then supported by a number of instruments, each with its own hardware-software instrument-based controller. Advantages of the instrument-based control architecture and framework include reusability, testability, and improved reliability of the deployed

  1. Target Diagnostic Instrument-Based Controls Framework for the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Shelton, R; O' Brien, D; Nelson, J; Kamperschroer, J

    2007-05-07

    NIF target diagnostics are being developed to observe and measure the extreme physics of targets irradiated by the 192-beam laser. The response time of target materials can be on the order of 100ps--the time it takes light to travel 3 cm--temperatures more than 100 times hotter than the surface of the sun, and pressures that exceed 109 atmospheres. Optical and x-ray diagnostics were developed and fielded to observe and record the results of the first 4-beam experiments at NIF. Hard and soft x-ray spectra were measured, and time-integrated and gated x-ray images of hydrodynamics experiments were recorded. Optical diagnostics recorded backscatter from the target, and VISAR laser velocimetry measurements were taken of laser-shocked target surfaces. Additional diagnostics are being developed and commissioned to observe and diagnose ignition implosions, including various neutron and activation diagnostics. NIF's diagnostics are being developed at LLNL and with collaborators at other sites. To accommodate the growing number of target diagnostics, an Instrument-Based Controls hardware-software framework has been developed to facilitate development and ease integration into the NIF Integrated Computer Control System (ICCS). Individual WindowsXP PC controllers for each digitizer, power supply and camera (i.e., instruments) execute controls software unique to each instrument model. Each hardware-software controller manages a single instrument, in contrast to the complexity of combining all the controls software needed for a diagnostic into a single controller. Because of this simplification, controllers can be more easily tested on the actual hardware, evaluating all normal and off-normal conditions. Each target diagnostic is then supported by a number of instruments, each with its own hardware-software instrument-based controller. Advantages of the instrument-based control architecture and framework include reusability, testability, and improved reliability of the

  2. Development and testing of hydrogen ignition devices

    International Nuclear Information System (INIS)

    Renfro, D.; Smith, L.; Thompson, L.; Clever, R.

    1982-01-01

    Controlled ignition systems for the mitigation of hydrogen produced during degraded core accidents have been installed recently in several light water reactor (LWR) containments. This paper relates the background of the thermal igniter approach and its application to LWR controlled ignition systems. The process used by the Tennessee Valley Authority (TVA) to select a hydrogen mitigation system in general and an igniter type in particular is described. Descriptions of both the Interim Distributed Ignition System and the Permanent Hydrogen Mitigation System installed by TVA are included as examples. Testing of igniter durability at TVA's Singleton Materials Engineering Laboratory and of igniter performance at Atomic Energy of Canada's Whiteshell Nuclear Research Establishment is presented

  3. Easy Korean Auto CAD 14

    International Nuclear Information System (INIS)

    Lee, Jae Cheol

    1997-10-01

    This book introduces Auto CAD 14, which includes summary of basic things of Auto CAD 14, user interface for Auto CAD, basic drawing and advice, layer and set-up drawing, drawing with Auto CAD tools exactly, basic drawing of every thing, edit command, control of display, modeling and view ports of drawing space, various things drawing, writing letters, modification of floor plan, and check, block, X ref, lines and hatch, writing measurement, floor plan and OLE exchange of data, 3D floor plan, and rendering and presentation.

  4. Combustion in a High-Speed Compression-Ignition Engine

    Science.gov (United States)

    Rothrock, A M

    1933-01-01

    An investigation conducted to determine the factors which control the combustion in a high-speed compression-ignition engine is presented. Indicator cards were taken with the Farnboro indicator and analyzed according to the tangent method devised by Schweitzer. The analysis show that in a quiescent combustion chamber increasing the time lag of auto-ignition increases the maximum rate of combustion. Increasing the maximum rate of combustion increases the tendency for detonation to occur. The results show that by increasing the air temperature during injection the start of combustion can be forced to take place during injection and so prevent detonation from occurring. It is shown that the rate of fuel injection does not in itself control the rate of combustion.

  5. High frequency ignition arrangement

    Energy Technology Data Exchange (ETDEWEB)

    Canup, R E

    1977-03-03

    The invention concerns an HF ignition arrangement for combustion engines with a transistor oscillator. As this oscillator requires a current of 10A, with peak currents up to about 50A, it is not sensible to take this current through the remote ignition switch for switching it on and off. According to the invention the HF high voltage transformer of the ignition is provided with a control winding, which only requires a few milliamps DC and which can therefore be switched via the ignition switch. If the ignition switch is in the 'running' position, then a premagnetising DC current flows through the control winding, which suppresses the oscillation of the oscillator which has current flowing through it, until this current is interrupted by the interruptor contacts controlled by the combustion engine, so that the oscillations of the oscillator start immediately; the oscillator only continues to oscillate during the period during which the interruptor contacts controlled by the machine are open and interrupt the premagnetisation current. The control winding is short circuited in the 'off' position of the ignition switch.

  6. Auto Market

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    <正> Editor’s notes: the "online investigation of the updated condition of auto market in China", organized by BAGAE together with 7 websites, ended recently. The participants were from 32 provinces, cities and autonomous regions throughout China. Diplomas of the 4,657 participants were generally high, of which college or/over accounted for 80.7%; the participants were mainly middle-aged and young people in which 92.1% were below 40 years old.

  7. Skip cycle method with a valve-control mechanism for spark ignition engines

    International Nuclear Information System (INIS)

    Baykara, Cemal; Akin Kutlar, O.; Dogru, Baris; Arslan, Hikmet

    2017-01-01

    Highlights: • A normal four-stroke cycle followed by a skip cycle without gas exchange is tested. • The normal and skipped mode results are compared at equal power levels. • The throttle valve is opened wider, thereby resulting in a higher volumetric efficiency. • The pumping work during the gas exchange decreases significantly. • The fuel consumption (BSFC) is reduced by approximately 14–26% under part load conditions. - Abstract: The efficiency decrease of spark ignition (SI) engines under part-load conditions is a considerable issue. Changing the effective stroke volume based on the load level is one of the methods using to improve the part-load efficiency. In this study, a novel alternative engine valve control technique in order to perform a cycle without gas exchange (skip cycle), is examined. The goal of skip cycle strategy is to reduce the effective stroke volume of an engine under part load conditions by skipping several of the four stroke cycles by cutting off the fuel injection and simultaneously deactivating the inlet and exhaust valves. To achieve the same power level in the skip cycle, the cylinder pressure level reaches higher values compared to those in a normal four stroke cycle operation, but inherently not higher than the maximum one at full load of normal cycle. According to the experimental results, the break specific fuel consumption (BSFC) was reduced by 14–26% at a 1–3 bar break mean effective pressure (BMEP) and a 1200–1800 rpm engine speed of skip cycle operation, in comparison to normal engine operation. The significant decrease in the pumping work from the gas exchange is one of the primary factors for an increase in efficiency under part load conditions. As expected, the fuel consumption reduction rate at lower load conditions was higher. These experimental results indicate a promising potential of the skip cycle system for reducing the fuel consumption under part load conditions.

  8. First industrial application of MAG STT welding with auto adaptative joint control

    International Nuclear Information System (INIS)

    Tran Tien, Thong

    2006-01-01

    The Welding Institute has participated to an extraordinary plan: the manufacture of the new LHC (Large Hadron Collider) particles accelerator in a circular tunnel of 27 km of circumference, at the European laboratory for particles physics (CERN) located at the Franco-Swiss frontier. The LHC dipolar magnets wires constituted in semi-cylinders of 15 m length in 316 LN, thickness 10 mm, are assembled in horizontal-vertical position. The Welding Institute has developed a software allowing to implement the auto-adaptative welding with follow of laser joint, using the MAG STT (Surface Tension Transfer) process. The modeling of welding laws connected with the strategy of joints filling runs (in multi-passes), absorb the physical tolerances of the preparation (clearance, poor alignment, root of joint...) and this in welding dynamical condition. (O.M.)

  9. A sustained-arc ignition system for internal combustion engines

    Science.gov (United States)

    Birchenough, A. G.

    1977-01-01

    A sustained-arc ignition system was developed for internal combustion engines. It produces a very-long-duration ignition pulse with an energy in the order of 100 millijoules. The ignition pulse waveform can be controlled to predetermined actual ignition requirements. The design of the sustained-arc ignition system is presented in the report.

  10. Dual-harmonic auto voltage control for the rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

    Directory of Open Access Journals (Sweden)

    Fumihiko Tamura

    2008-07-01

    Full Text Available The dual-harmonic operation, in which the accelerating cavities are driven by the superposition of the fundamental and the second harmonic rf voltage, is useful for acceleration of the ultrahigh intensity proton beam in the rapid cycling synchrotron (RCS of Japan Proton Accelerator Research Complex (J-PARC. However, the precise and fast voltage control of the harmonics is necessary to realize the dual-harmonic acceleration. We developed the dual-harmonic auto voltage control system for the J-PARC RCS. We describe details of the design and the implementation. Various tests of the system are performed with the RCS rf system. Also, a preliminary beam test has been done. We report the test results.

  11. AutoCAD platform customization user interface, AutoLISP, VBA, and beyond

    CERN Document Server

    Ambrosius, Lee

    2015-01-01

    Take control of AutoCAD to boost the speed, quality, and precision of your work Senior drafters and savvy users are increasingly taking AutoCAD customization out of the hands of system administrators, and taking control of their own workflow. In AutoCAD Platform Customization, Autodesk customization guru Lee Ambrosius walks you through a multitude of customization options using detailed tutorials and real-world examples applicable to AutoCAD, AutoCAD LT, Civil 3D, Plant 3D, and other programs built on the AutoCAD platform. By unleashing the full power of the software, you'll simplify and str

  12. Spectroscoping analysis of ignition in a spark ignition engine with jet-controlled combustion; Spektroskopische Untersuchung der Entflammung an einem Ottomotor mit strahlgefuehrtem Brennverfahren

    Energy Technology Data Exchange (ETDEWEB)

    Palaveev, S. [MOT Forschungs- und Entwicklungsgesellschaft fuer Motorentechnik, Optik und Thermodynamik GmbH, Karlsruhe (Germany); Buri, S.; Xander, B.; Spicher, U. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Kolbenmaschinen

    2007-07-01

    The gasoline direct injection engine is one of the most promising strategies today to reduce the fuel consumption and CO{sub 2}-emissions of spark-ignition engines. The commercial launch of that combustion system was possible only through the development of new optical measurement techniques, which have been a major contribution for understanding the basics of the combustion in a stratified mode. In terms of space and time, compared to the homogeneous approach, the air-fuel-ratio for a stratified mode may vary significantly. This fluctuation affects in a critical way the process of ignition and combustion. The knowledge of the air-fuel-ratio in the spark plug area both at time of ignition and in during the combustion is therefore critical for the development of this combustion system and it components. This paper presents the spark-emission spectroscopy as a non invasive optical technique for measuring the air-fuel-ratio {lambda} in the spark gap at time of ignition. (orig.)

  13. Adaptive threshold control for auto-rate fallback algorithm in IEEE 802.11 multi-rate WLANs

    Science.gov (United States)

    Wu, Qilin; Lu, Yang; Zhu, Xiaolin; Ge, Fangzhen

    2012-03-01

    The IEEE 802.11 standard supports multiple rates for data transmission in the physical layer. Nowadays, to improve network performance, a rate adaptation scheme called auto-rate fallback (ARF) is widely adopted in practice. However, ARF scheme suffers performance degradation in multiple contending nodes environments. In this article, we propose a novel rate adaptation scheme called ARF with adaptive threshold control. In multiple contending nodes environment, the proposed scheme can effectively mitigate the frame collision effect on rate adaptation decision by adaptively adjusting rate-up and rate-down threshold according to the current collision level. Simulation results show that the proposed scheme can achieve significantly higher throughput than the other existing rate adaptation schemes. Furthermore, the simulation results also demonstrate that the proposed scheme can effectively respond to the varying channel condition.

  14. The simulation study on the Nuclear Heating Reactor's power auto-control system

    International Nuclear Information System (INIS)

    Yang Zhijun; Liu Longzhi; Hu Guifen

    2000-01-01

    The power automatic control system on nuclear heating reactor (NHR) is a multi-input and multi-output non-linear system. The power automatic control system on NHR is studied by modern control theory. Through the simulation experiments, it is clear that adopting μ outer-loop and LQR inner-loop feedback, the best control results are obtained

  15. A Soft Sensor-Based Fault-Tolerant Control on the Air Fuel Ratio of Spark-Ignition Engines

    Directory of Open Access Journals (Sweden)

    Yu-Jia Zhai

    2017-01-01

    Full Text Available The air/fuel ratio (AFR regulation for spark-ignition (SI engines has been an essential and challenging control problem for engineers in the automotive industry. The feed-forward and feedback scheme has been investigated in both academic research and industrial application. The aging effect can often cause an AFR sensor fault in the feedback loop, and the AFR control performance will degrade consequently. In this research, a new control scheme on AFR with fault-tolerance is proposed by using an artificial neural network model based on fault detection and compensation, which can provide the satisfactory AFR regulation performance at the stoichiometric value for the combustion process, given a certain level of misreading of the AFR sensor.

  16. Modeling and controller design architecture for cycle-by-cycle combustion control of homogeneous charge compression ignition (HCCI) engines – A comprehensive review

    International Nuclear Information System (INIS)

    Fathi, Morteza; Jahanian, Omid; Shahbakhti, Mahdi

    2017-01-01

    Highlights: • Addressing accuracy-speed compromise of HCCI representation is very important. • Phasing, load, exhaust temperature and emissions are the most important outputs. • Separability between the effects of the inputs on the outputs is of great interest. • Existing actuation systems combining inputs are favorable. • An HCCI controller should be a fast and robust one to become a viable solution. - Abstract: Homogeneous charge compression ignition (HCCI) combustion engines are advantageous in terms of good fuel economy and low levels of soot-nitrogen oxides (NOx) emissions. However, they are accompanied with some intrinsic challenges, the most important of which is the lack of any direct control method for ignition trigger. Thus, implementation of HCCI combustion is in fact a control problem, and an optimized control structure is required for attaining the inherent benefits of HCCI. The control structure consists of a proper representation of engine processes; a suitable selection of state variables; useful and applicable set of inputs, outputs and observers; appropriate fixed or variable set-points for controlled parameters; instrumentations including sensors and actuators; and an applicable control law implemented in a controller. The present paper aims at addressing these issues altogether by introducing HCCI engine control structure in progress and presenting highlights from literature. Research should result in appropriately controlled HCCI engines which can provide desired load at rated speed with acceptable performance and emissions characteristics.

  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. Breakdown plasma and vortex flow control for laser ignition using a combination of nano- and femto-second lasers.

    Science.gov (United States)

    Kojima, Hirokazu; Takahashi, Eiichi; Furutani, Hirohide

    2014-01-13

    The breakdown plasma and successive flow leading to combustion are controlled by the combination of a nano-second Nd:YAG laser and a femto-second Ti:Sapphire (TiS) laser. The behaviors are captured by an intensified charged coupled device (ICCD) camera and a high-speed schlieren optical system. The TiS laser determines the initial position of the breakdown by supplying the initial electrons in the optical axis of focusing YAG laser pulses. We show that the initial position of the breakdown can be controlled by the incident position of the TiS laser. In addition, the ignition lean limit of the flammable mixture changes depending on the TiS laser incident position, which is influenced by hot gas distribution and the flow in the flame kernel.

  19. Dependence of CIT [Compact Ignition Tokamak] PF [poloidal field] coil currents on profile and shape parameters using the Control Matrix

    International Nuclear Information System (INIS)

    Strickler, D.J.; Peng, Y-K.M.; Jardin, S.C.; Pomphrey, N.

    1990-01-01

    The plasma shaping flexibility of the Compact Ignition Tokamak (CIT) poloidal field (PF) coil set is demonstrated through MHD equilibrium calculations of optimal PF coil current distributions and their variation with poloidal beta, internal inductance, plasma 95% elongation, and 95% triangularity. Calculations of the magnetic stored energy are used to compare solutions associated with various plasma parameters. The Control Matrix (CM) equilibrium code, together with the nonlinear equation and numerical optimization software packages HYBRD, and VMCON, respectively, are used to find equilibrium coil current distributions for fixed divertor geometry, volt-seconds, and plasma profiles in order to isolate the dependence on individual parameters. A reference equilibrium and coil current distribution are chosen, and correction currents dI are determined using the CM equilibrium method to obtain other specified plasma shapes. The reference equilibrium is the κ = 2 divertor at beginning of flattop (BOFT) with a minimum stored energy solution for the coil current distribution. The pressure profile function is fixed

  20. Electrically controlled fuel injection system for an externally ignited internal combustion engine. Elektrisch gesteuerte Kraftstoffeinspritzanlage fuer eine fremdgezuendete Brennkraftmaschine

    Energy Technology Data Exchange (ETDEWEB)

    Busse, W; Drews, U; Werner, P

    1980-12-04

    The purpose of the invention is to create an electrically controlled fuel injection system with a pulse shaping stage, which can be manufactured by integrated circuit technique and which is protected against faulty initiation, which could be caused by interference from the ignition system. According to the invention the problem is solved by the pulse shaping stage containing a monostable multivibrator set to a predetermined period for changeover, preferably about 4 millisecs, which includes a first transistor blocked in the de-energised state and a second transistor conducting in the de-energised state, whose base is connected via a coupling capacity determining the period of changeover to the collector of the first transistor, and which also has a charging transistor. This is connected to the collector of the first transistor and its collector is connected via a resistor to the DC supply wire.

  1. Control voltage of the generator of auto-excited induction for applications on micro/mini generation o electric power; Control de voltaje del generador de induccion auto-excitado para aplicaciones de micro/mini generacion de energia electrica

    Energy Technology Data Exchange (ETDEWEB)

    Torres Montalvo, Emmanuel

    2006-09-15

    Although only one part of the mini/micro hydraulic power has been exploited in our country, this type of electric energy generation can be considered as a visible way of electricity generation, mainly related to the ecological, economical and social aspects. The impact that these power plants can have in the regions in which they are installed is always positive: cost energy cost reduction, economical spills and mainly a social welfare. The electric energy is one of the pillars for the economical development of a country and provides a better life quality. Nowadays the research and the technology oriented to the operation and control of the micro/mini power plants has awaken the interest of many researchers in several countries of the world as China, India, Canada, and USA to mention some of them. The induction generator plays a crucial role in the uses of these technologies. The work of Basset and Potter in 1935 is the angular stone over the possibility of generating energy making use of the induction machine and a capacitors bank connected to the machine terminals. This configuration is known as induction auto-excited generator (GIAE). Several investigations have been realized that deal about the functioning principle and the dynamic behavior a GIAE, which can supply electric power in remote isolated regions. In the existing literature have been proposed control strategies to offer voltage regulations and/or frequency into the acceptable range. Some of these control strategies present problems such a demand of a reactive power, harmonics injections in the system, the control circuits are complicated, expensive and voluminous and prone to fail. This paper realizes an analysis of the necessary and sufficient conditions so that an induction machine can operate as GIAE. The corresponding curves are presented for each studied case. The dynamic behavior of the voltage and the frequency generated by the GIAE are studied in detail, which is a contribution to the existing

  2. Knowledge of allergies and performance in epinephrine auto-injector use: a controlled intervention in preschool teachers.

    Science.gov (United States)

    Dumeier, Henriette Karoline; Richter, Luca Anne; Neininger, Martina Patrizia; Prenzel, Freerk; Kiess, Wieland; Bertsche, Astrid; Bertsche, Thilo

    2018-04-01

    Epinephrine auto-injectors are used for first aid in anaphylactic emergencies by non-healthcare professionals, e.g., (pre-)school teachers. We developed an education session for preschool teachers addressing allergies, anaphylactic emergencies, and administering auto-injectors. We assessed their attitudes and knowledge in allergies and anaphylactic emergency by a questionnaire and monitored their practical performance in administering auto-injectors before the education session, directly after, and 4-12 weeks after the session. From 75 teachers giving their consent to participate, 81% had children with allergies under their supervision and 3% had already administered medication from an available rescue kit. The knowledge of triggers of allergies increased from 9 to 55% directly and to 33% 4-12 weeks after the session (both p < 0.001, compared to baseline). Directly after the session, the number of teachers who felt well-prepared for an anaphylactic emergency rose from 11 to 88%, which decreased to 79% 4-12 weeks thereafter (each p < 0.001). The number of auto-injector administrations without any drug-related problems increased from 3 to 35% directly after the session and shrunk to 16% 4-12 weeks afterwards (both p < 0.025). A single education session substantially improved preschool teachers' attitudes and knowledge in allergies and anaphylactic emergencies. Additionally, their practical performance in auto-injector administration increased. What is Known: • Food allergies are increasing among children. • The knowledge about allergies and anaphylactic emergencies is poor. What is New: • The proportion of teachers who felt well-prepared for an anaphylactic emergency increased after a single education session. • The proportion of auto-injector administrations without any drug-related problems additionally increased due to an education session.

  3. Enzyme controlled glucose auto-delivery for high cell density cultivations in microplates and shake flasks

    Directory of Open Access Journals (Sweden)

    Casteleijn Marco G

    2008-11-01

    Full Text Available Abstract Background Here we describe a novel cultivation method, called EnBase™, or enzyme-based-substrate-delivery, for the growth of microorganisms in millilitre and sub-millilitre scale which yields 5 to 20 times higher cell densities compared to standard methods. The novel method can be directly applied in microwell plates and shake flasks without any requirements for additional sensors or liquid supply systems. EnBase is therefore readily applicable for many high throughput applications, such as DNA production for genome sequencing, optimisation of protein expression, production of proteins for structural genomics, bioprocess development, and screening of enzyme and metagenomic libraries. Results High cell densities with EnBase are obtained by applying the concept of glucose-limited fed-batch cultivation which is commonly used in industrial processes. The major difference of the novel method is that no external glucose feed is required, but glucose is released into the growth medium by enzymatic degradation of starch. To cope with the high levels of starch necessary for high cell density cultivation, starch is supplied to the growing culture suspension by continuous diffusion from a storage gel. Our results show that the controlled enzyme-based supply of glucose allows a glucose-limited growth to high cell densities of OD600 = 20 to 30 (corresponding to 6 to 9 g l-1 cell dry weight without the external feed of additional compounds in shake flasks and 96-well plates. The final cell density can be further increased by addition of extra nitrogen during the cultivation. Production of a heterologous triosphosphate isomerase in E. coli BL21(DE3 resulted in 10 times higher volumetric product yield and a higher ratio of soluble to insoluble product when compared to the conventional production method. Conclusion The novel EnBase method is robust and simple-to-apply for high cell density cultivation in shake flasks and microwell plates. The

  4. Auto-control of pumping operations in sewerage systems by rule-based fuzzy neural networks

    Directory of Open Access Journals (Sweden)

    Y.-M. Chiang

    2011-01-01

    Full Text Available Pumping stations play an important role in flood mitigation in metropolitan areas. The existing sewerage systems, however, are facing a great challenge of fast rising peak flow resulting from urbanization and climate change. It is imperative to construct an efficient and accurate operating prediction model for pumping stations to simulate the drainage mechanism for discharging the rainwater in advance. In this study, we propose two rule-based fuzzy neural networks, adaptive neuro-fuzzy inference system (ANFIS and counterpropagation fuzzy neural network for on-line predicting of the number of open and closed pumps of a pivotal pumping station in Taipei city up to a lead time of 20 min. The performance of ANFIS outperforms that of CFNN in terms of model efficiency, accuracy, and correctness. Furthermore, the results not only show the predictive water levels do contribute to the successfully operating pumping stations but also demonstrate the applicability and reliability of ANFIS in automatically controlling the urban sewerage systems.

  5. Effect of laser induced plasma ignition timing and location on Diesel spray combustion

    International Nuclear Information System (INIS)

    Pastor, José V.; García-Oliver, José M.; García, Antonio; Pinotti, Mattia

    2017-01-01

    Highlights: • Laser plasma ignition is applied to a direct injection Diesel spray, compared with auto-ignition. • Critical local fuel/air ratio for LIP provoked ignition is obtained. • The LIP system is able to stabilize Diesel combustion compared to auto-ignition cases. • Varying LIP position along spray axis directly affects Ignition-delay. • Premixed combustion is reduced both by varying position and delay of the LIP ignition system. - Abstract: An experimental study about the influence of the local conditions at the ignition location on combustion development of a direct injection spray is carried out in an optical engine. A laser induced plasma ignition system has been used to force the spray ignition, allowing comparison of combustion’s evolution and stability with the case of conventional autoignition on the Diesel fuel in terms of ignition delay, rate of heat release, spray penetration and soot location evolution. The local equivalence ratio variation along the spray axis during the injection process was determined with a 1D spray model, previously calibrated and validated. Upper equivalence ratios limits for the ignition event of a direct injected Diesel spray, both in terms of ignition success possibilities and stability of the phenomena, could been determined thanks to application of the laser plasma ignition system. In all laser plasma induced ignition cases, heat release was found to be higher than for the autoignition reference cases, and it was found to be linked to a decrease of ignition delay, with the premixed peak in the rate of heat release curve progressively disappearing as the ignition delay time gets shorter. Ignition delay has been analyzed as a function of the laser position, too. It was found that ignition delay increases for plasma positions closer to the nozzle, indicating that the amount of energy introduced by the laser induced plasma is not the only parameter affecting combustion initiation, but local equivalence ratio

  6. Electronic ignition system for internal combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Crowder, L W

    1980-11-20

    Mechanical ignition adjustment devices are sensitive to many effects, for example breakage, faults due to manufacturing tolerances, play in the linkage and the effect of a dirty or corrosive environment. It is therefore the purpose of the invention to provide an electronic ignition system which avoids the disadvantages of a mechanical system. The invention provides adjustment of the ignition point, which gives advance of the ignition timing with increasing speed. An output signal is formed, which supersedes the signal supplied by the electronic control system, so that the ignition is advanced. This also occurs with a larger crankshaft angle before top dead centre of the engine. The electronic control system combines with a source of AC time signals which has a generator as electrical transmitter and a DC battery and ignition coil. The rotor of the electrical generator is driven synchronised with the engine. Structural and functional details of the transistor control circuits are given in 5 patent claims.

  7. La auditoría de control de la calidad y los niveles de auto-evaluación y acreditación universitaria

    OpenAIRE

    Rojas García, José Domingo

    2014-01-01

    Determina de qué manera la auditoria de calidad influye en los niveles de evaluación y acreditación universitaria. Se investigaron temas muy puntuales relacionados con la calidad de la educación superior, por ejemplo: el control de calidad como herramienta de la auditoría, las acciones y recomendaciones de auditoría de calidad relacionadas con los niveles de auto-evaluación y acreditación universitaria. Durante la investigación, se consultó bibliografía vinculada con la auditoría de control d...

  8. Ignition circuit for combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Becker, H W

    1977-05-26

    The invention refers to the ignition circuit for combustion engines, which are battery fed. The circuit contains a transistor and an oscillator to produce an output voltage on the secondary winding of an output transformer to supply an ignition current. The plant is controlled by an interrupter. The purpose of the invention is to form such a circuit that improved sparks for ignition are produced, on the one hand, and that on the other hand, the plant can continue to function after loss of the oscillator. The problem is solved by the battery and the secondary winding of the output transformers of the oscillator are connected via a rectifier circuit to produce a resultant total voltage with the ignition coil from the battery voltage and the rectified pulsating oscillator output.

  9. Instant AutoIt scripting

    CERN Document Server

    Laso, Emilio Aristides de Fez

    2013-01-01

    Filled with practical, step-by-step instructions and clear explanations for the most important and useful tasks. This is a Packt Instant How-to guide, which provides concise and clear recipes for getting started with AutoIt.Instant AutoIt Scripting Essentials How-to is for beginners who wish to know more about automation and programming, system administration developers who intent to automate/manage clusters and servers, and for computer programmers who want to control any PC to create seamless automation apps.

  10. Flamelet Generated Manifold Strategies in Modeling of an Igniting Diesel Spray

    NARCIS (Netherlands)

    Bekdemir, C.; Somers, L.M.T.; Goey, de L.P.H.

    2009-01-01

    A study is presented on the modeling of fuel spray combustion in diesel engines. The objective is to model igniting diesel sprays with the detailed chemistry tabulation method FGM (Flamelet GeneratedManifold). The emphasis is on the accurate prediction of auto-ignition as well as the steady

  11. 2-Methylfuran: A bio-derived octane booster for spark-ignition engines

    KAUST Repository

    Sarathy, Mani; Shankar, Vijai; Tripathi, Rupali; Pitsch, Heinz; Sarathy, Mani

    2018-01-01

    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

  12. Experimental investigations of effects of EGR on performance and emissions characteristics of CNG fueled reactivity controlled compression ignition (RCCI) engine

    International Nuclear Information System (INIS)

    Singh Kalsi, Sunmeet; Subramanian, K.A.

    2016-01-01

    Highlights: • NO_x emission decreased drastically in RCCI engine with EGR. • CO and HC emissions decreased with 8% EGR. • Smoke emission increased with EGR but is still less than base diesel. • Brake thermal efficiency does not change with EGR up to 15% • 8% EGR is optimum based on less CO, HC, NO_x except smoke. - Abstract: Experimental: tests were carried out on a single cylinder diesel engine (7.4 kW rated power at 1500 rpm) under dual fuel mode (CNG-Diesel) with EGR (exhaust gas recirculation). Less reacting fuel (CNG) was injected inside the intake manifold using timed manifold gas injection system whereas high reactive diesel fuel was directly injected into the engine’s cylinder for initiation of ignition. EGR at different percentages (8%, 15% and 30%) was inducted to the engine through intake manifold and tests were conducted at alternator power output of 2 kW and 5 kW. The engine can operate under dual fuel mode with maximum CNG energy share of 85% and 92% at 5 kW and 2 kW respectively. The brake thermal efficiency of diesel engine improved marginally at 5 kW power output under conventional dual fuel mode with the CNG share up to 37% whereas the efficiency did not change with up to 15% EGR however it decreased beyond the EGR percentage. NO_x emission in diesel engine under conventional dual fuel mode decreased significantly and it further decreased drastically with EGR. The notable point emerged from this study is that CO and HC emissions, which are major problems at part load in reactivity controlled compression ignition engine (RCCI), decreased with 8% EGR along with further reduction of NO_x. However, smoke emission is marginally higher with EGR than without EGR but it is still less than conventional mode (Diesel alone). The new concept emerged from this study is that CO and HC emissions of RCCI engine at part load can be reduced using EGR.

  13. Building a World-Class Safety Culture: The National Ignition Facility and the Control of Human and Organizational Error

    International Nuclear Information System (INIS)

    Bennett, C T; Stalnaker, G

    2002-01-01

    Accidents in complex systems send us signals. They may be harbingers of a catastrophe. Some even argue that a ''normal'' consequence of operations in a complex organization may not only be the goods it produces, but also accidents and--inevitably--catastrophes. We would like to tell you the story of a large, complex organization, whose history questions the argument ''that accidents just happen.'' Starting from a less than enviable safety record, the National Ignition Facility (NIF) has accumulated over 2.5 million safe hours. The story of NIF is still unfolding. The facility is still being constructed and commissioned. But the steps NIF has taken in achieving its safety record provide a principled blueprint that may be of value to others. Describing that principled blueprint is the purpose of this paper. The first part of this paper is a case study of NIF and its effort to achieve a world-class safety record. This case study will include a description of (1) NIF's complex systems, (2) NIF's early safety history, (3) factors that may have initiated its safety culture change, and (4) the evolution of its safety blueprint. In the last part of the paper, we will compare NIF's safety culture to what safety industry experts, psychologists, and sociologists say about how to shape a culture and control organizational error

  14. National Ignition Facility subsystem design requirements supervisory control software SSDR 1.5.2

    International Nuclear Information System (INIS)

    Woodruff, J.; VanArsdall, P.; Bliss, E.

    1996-01-01

    This System Design Requirement document establishes the performance, design, development, and test requirements for the Supervisory Control Software, WBS 1.5.2, which is part of the NIF Integrated Computer Control System (ICCS). This document responds directly to the requirements detailed in ICCS (WBS 1-5)

  15. National Ignition Facility system design requirements NIF integrated computer controls SDR004

    International Nuclear Information System (INIS)

    Bliss, E.

    1996-01-01

    This System Design Requirement document establishes the performance, design, development, and test requirements for the NIF Integrated Computer Control System. The Integrated Computer Control System (ICCS) is covered in NIF WBS element 1.5. This document responds directly to the requirements detailed in the NIF Functional Requirements/Primary Criteria, and is supported by subsystem design requirements documents for each major ICCS Subsystem

  16. High signal-to-noise ratio sensing with Shack–Hartmann wavefront sensor based on auto gain control of electron multiplying CCD

    International Nuclear Information System (INIS)

    Zhu Zhao-Yi; Li Da-Yu; Hu Li-Fa; Mu Quan-Quan; Yang Cheng-Liang; Cao Zhao-Liang; Xuan Li

    2016-01-01

    High signal-to-noise ratio can be achieved with the electron multiplying charge-coupled-device (EMCCD) applied in the Shack–Hartmann wavefront sensor (S–H WFS) in adaptive optics (AO). However, when the brightness of the target changes in a large scale, the fixed electron multiplying (EM) gain will not be suited to the sensing limitation. Therefore an auto-gain-control method based on the brightness of light-spots array in S–H WFS is proposed in this paper. The control value is the average of the maximum signals of every light spot in an array, which has been demonstrated to be kept stable even under the influence of some noise and turbulence, and sensitive enough to the change of target brightness. A goal value is needed in the control process and it is predetermined based on the characters of EMCCD. Simulations and experiments have demonstrated that this auto-gain-control method is valid and robust, the sensing SNR reaches the maximum for the corresponding signal level, and especially is greatly improved for those dim targets from 6 to 4 magnitude in the visual band. (special topic)

  17. Fundamental Interactions in Gasoline Compression Ignition Engines with Fuel Stratification

    Science.gov (United States)

    Wolk, Benjamin Matthew

    Transportation accounted for 28% of the total U.S. energy demand in 2011, with 93% of U.S. transportation energy coming from petroleum. The large impact of the transportation sector on global climate change necessitates more-efficient, cleaner-burning internal combustion engine operating strategies. One such strategy that has received substantial research attention in the last decade is Homogeneous Charge Compression Ignition (HCCI). Although the efficiency and emissions benefits of HCCI are well established, practical limits on the operating range of HCCI engines have inhibited their application in consumer vehicles. One such limit is at high load, where the pressure rise rate in the combustion chamber becomes excessively large. Fuel stratification is a potential strategy for reducing the maximum pressure rise rate in HCCI engines. The aim is to introduce reactivity gradients through fuel stratification to promote sequential auto-ignition rather than a bulk-ignition, as in the homogeneous case. A gasoline-fueled compression ignition engine with fuel stratification is termed a Gasoline Compression Ignition (GCI) engine. Although a reasonable amount of experimental research has been performed for fuel stratification in GCI engines, a clear understanding of how the fundamental in-cylinder processes of fuel spray evaporation, mixing, and heat release contribute to the observed phenomena is lacking. Of particular interest is gasoline's pressure sensitive low-temperature chemistry and how it impacts the sequential auto-ignition of the stratified charge. In order to computationally study GCI with fuel stratification using three-dimensional computational fluid dynamics (CFD) and chemical kinetics, two reduced mechanisms have been developed. The reduced mechanisms were developed from a large, detailed mechanism with about 1400 species for a 4-component gasoline surrogate. The two versions of the reduced mechanism developed in this work are: (1) a 96-species version and (2

  18. National Ignition Facility, subsystem design requirements beam control and laser diagnostics SSDR 1.7

    International Nuclear Information System (INIS)

    Bliss, E.

    1996-01-01

    This Subsystem Design Requirement document is a development specification that establishes the performance, design, development, and test requirements for the Alignment subsystem (WBS 1.7.1), Beam Diagnostics (WBS 1.7.2), and the Wavefront Control subsystem (WBS 1.7. 3) of the NIF Laser System (WBS 1.3). These three subsystems are collectively referred to as the Beam Control ampersand Laser Diagnostics Subsystem. The NIF is a multi-pass, 192-beam, high-power, neodymium-glass laser that meets requirements set forth in the NIF SDR 002 (Laser System). 3 figs., 3 tabs

  19. Learning Auto CAD 2004

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Gyeong Su; Song, Chun Dong; Park, Hyeong Jin; Kim, Yeong Min

    2004-02-15

    This book introduces basic knowledge of AutoCAD, practice method of command of AutoCAD like poly line, rotate, copy, break, trim, stretch, lengthen, chamfer, grips, extend, array polygon, spline, hatch, and image, writing letters, making library, application of design center and tool palette, drawing floor plan elevation, cross-sectional diagram, presentation materials, effective application of AutoCAD, and construction design using CAD POWER 2004.

  20. Easy Auto CAD

    International Nuclear Information System (INIS)

    Lee, Hyeon Jun

    1996-02-01

    This book explains Auto CAD easily, which introduces improved function in Auto CAD R 13, such as direct import and export of 3 DS pile, revised render order structure, and explanations of assist, view Draw, construct and modify. Next it gives descriptions of Auto CAD conception, application and system. The last part deals with line, arc, circle, ellipse, erase, undo, redo, redraw, line type, multi line, limits, zoom, move, copy, rotate, array, mirror, grid, snap, units, offset and poly line.

  1. Learning Auto CAD 2004

    International Nuclear Information System (INIS)

    Shin, Gyeong Su; Song, Chun Dong; Park, Hyeong Jin; Kim, Yeong Min

    2004-02-01

    This book introduces basic knowledge of AutoCAD, practice method of command of AutoCAD like poly line, rotate, copy, break, trim, stretch, lengthen, chamfer, grips, extend, array polygon, spline, hatch, and image, writing letters, making library, application of design center and tool palette, drawing floor plan elevation, cross-sectional diagram, presentation materials, effective application of AutoCAD, and construction design using CAD POWER 2004.

  2. Understanding Biomass Ignition in Power Plant Mills

    DEFF Research Database (Denmark)

    Schwarzer, Lars; Jensen, Peter Arendt; Glarborg, Peter

    2017-01-01

    . This is not very well explained by apply-ing conventional thermal ignition theory. An experimental study at lab scale, using pinewood as an example fuel, was conducted to examine self-heating and self-ignition. Supplemental experiments were performed with bituminous coal. Instead of characterizing ignition......Converting existing coal fired power plants to biomass is a readily implemented strategy to increase the share of renewable energy. However, changing from one fuel to another is not straightforward: Experience shows that wood pellets ignite more readily than coal in power plant mills or storages...... temperature in terms of sample volume, mass-scaling seems more physically correct for the self-ignition of solids. Findings also suggest that the transition between self-heating and self-ignition is controlled both by the availability of reactive material and temperature. Comparison of experiments at 20...

  3. Ozone applied to the homogeneous charge compression ignition engine to control alcohol fuels combustion

    International Nuclear Information System (INIS)

    Masurier, J.-B.; Foucher, F.; Dayma, G.; Dagaut, P.

    2015-01-01

    Highlights: • Ozone was useful to control combustion phasing of alcohol fuels in HCCI engine. • Ozone helps to improve the combustion and advance its phasing. • Butanol is more impacted by ozone than methanol and ethanol. • HCCI combustion parameters may be controlled by managing ozone concentration. • Kinetics demonstrates that alcohol fuels are initially oxidized by O-atoms. - Abstract: The present investigation examines the impact of seeding the intake of an HCCI engine with ozone, one of the most oxidizing chemical species, on the combustion of three alcohol fuels: methanol, ethanol and n-butanol. The research was performed through engine experiments and constant volume computations. The results showed that increasing the ozone concentration led to an improvement in combustion coupled with a combustion advance. It was also observed, by comparing the results for each fuel selected, that n-butanol is the most impacted by ozone seeding and methanol the least. Further analyses of the experimental results showed that the alcohol fuel combustion can be controlled with ozone, which presents an interesting potential. Finally, computation results confirmed the experimental results observed. They also showed that in presence of ozone, alcohol fuels are not initially oxidized by molecular oxygen but by O-atoms coming from the ozone decomposition.

  4. Target diagnostic control system implementation for the National Ignition Facility (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Shelton, R. T.; Kamperschroer, J. H.; Lagin, L. J.; Nelson, J. R.; O' Brien, D. W. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2010-10-15

    The extreme physics of targets shocked by NIF's 192-beam laser is observed by a diverse suite of diagnostics. Many diagnostics are being developed by collaborators at other sites, but ad hoc controls could lead to unreliable and costly operations. A diagnostic control system (DCS) framework for both hardware and software facilitates development and eases integration. Each complex diagnostic typically uses an ensemble of electronic instruments attached to sensors, digitizers, cameras, and other devices. In the DCS architecture each instrument is interfaced to a low-cost WINDOWS XP processor and JAVA application. Each instrument is aggregated with others as needed in the supervisory system to form an integrated diagnostic. The JAVA framework provides data management, control services, and operator graphical user interface generation. DCS instruments are reusable by replication with reconfiguration for specific diagnostics in extensible markup language. Advantages include minimal application code, easy testing, and high reliability. Collaborators save costs by assembling diagnostics with existing DCS instruments. This talk discusses target diagnostic instrumentation used on NIF and presents the DCS architecture and framework.

  5. Target diagnostic control system implementation for the National Ignition Facility (invited)

    International Nuclear Information System (INIS)

    Shelton, R. T.; Kamperschroer, J. H.; Lagin, L. J.; Nelson, J. R.; O'Brien, D. W.

    2010-01-01

    The extreme physics of targets shocked by NIF's 192-beam laser is observed by a diverse suite of diagnostics. Many diagnostics are being developed by collaborators at other sites, but ad hoc controls could lead to unreliable and costly operations. A diagnostic control system (DCS) framework for both hardware and software facilitates development and eases integration. Each complex diagnostic typically uses an ensemble of electronic instruments attached to sensors, digitizers, cameras, and other devices. In the DCS architecture each instrument is interfaced to a low-cost WINDOWS XP processor and JAVA application. Each instrument is aggregated with others as needed in the supervisory system to form an integrated diagnostic. The JAVA framework provides data management, control services, and operator graphical user interface generation. DCS instruments are reusable by replication with reconfiguration for specific diagnostics in extensible markup language. Advantages include minimal application code, easy testing, and high reliability. Collaborators save costs by assembling diagnostics with existing DCS instruments. This talk discusses target diagnostic instrumentation used on NIF and presents the DCS architecture and framework.

  6. Study of ignition in a high compression ratio SI (spark ignition) methanol engine using LES (large eddy simulation) with detailed chemical kinetics

    International Nuclear Information System (INIS)

    Zhen, Xudong; Wang, Yang

    2013-01-01

    Methanol has been recently used as an alternative to conventional fuels for internal combustion engines in order to satisfy some environmental and economical concerns. In this paper, the ignition in a high compression ratio SI (spark ignition) methanol engine was studied by using LES (large eddy simulation) with detailed chemical kinetics. A 21-species, 84-reaction methanol mechanism was adopted to simulate the auto-ignition process of the methanol/air mixture. The MIT (minimum ignition temperature) and MIE (minimum ignition energy) are two important properties for designing safety standards and understanding the ignition process of combustible mixtures. The effects of the flame kernel size, flame kernel temperature and equivalence ratio were also examined on MIT, MIE and IDP (ignition delay period). The methanol mechanism was validated by experimental test. The simulated results showed that the flame kernel size, temperature and energy dramatically affected the values of the MIT, MIE and IDP for a methanol/air mixture, the value of the ignition delay period was not only related to the flame kernel energy, but also to the flame kernel temperature. - Highlights: • We used LES (large eddy simulation) coupled with detailed chemical kinetics to simulate methanol ignition. • The flame kernel size and temperature affected the minimum ignition temperature. • The flame kernel temperature and energy affected the ignition delay period. • The equivalence ratio of methanol–air mixture affected the ignition delay period

  7. Maximizing Power Output in Homogeneous Charge Compression Ignition (HCCI) Engines and Enabling Effective Control of Combustion Timing

    Science.gov (United States)

    Saxena, Samveg

    Homogeneous Charge Compression Ignition (HCCI) engines are one of the most promising engine technologies for the future of energy conversion from clean, efficient combustion. HCCI engines allow high efficiency and lower CO2 emission through the use of high compression ratios and the removal of intake throttle valves (like Diesel), and allow very low levels of urban pollutants like nitric oxide and soot (like Otto). These engines, however, are not without their challenges, such as low power density compared with other engine technologies, and a difficulty in controlling combustion timing. This dissertation first addresses the power output limits. The particular strategies for enabling high power output investigated in this dissertation focus on avoiding five critical limits that either damage an engine, drastically reduce efficiency, or drastically increase emissions: (1) ringing limits, (2) peak in-cylinder pressure limits, (3) misfire limits, (4) low intake temperature limits, and (5) excessive emissions limits. The research shows that the key factors that enable high power output, sufficient for passenger vehicles, while simultaneously avoiding the five limits defined above are the use of: (1) high intake air pressures allowing improved power output, (2) highly delayed combustion timing to avoid ringing limits, and (3) using the highest possible equivalence ratio before encountering ringing limits. These results are revealed by conducting extensive experiments spanning a wide range of operating conditions on a multi-cylinder HCCI engine. Second, this dissertation discusses strategies for effectively sensing combustion characteristics on a HCCI engine. For effective feedback control of HCCI combustion timing, a sensor is required to quantify when combustion occurs. Many laboratory engines use in-cylinder pressure sensors but these sensors are currently prohibitively expensive for wide-scale commercialization. Instead, ion sensors made from inexpensive sparkplugs

  8. Encapsulation of low density plastic foam materials for the fast ignition realization experiment (FIREX). Control of microstructure and density

    International Nuclear Information System (INIS)

    Nagai, Keiji; Yang, H.; Iwamoto, A.

    2008-10-01

    Development of foam capsule fabrication for cryogenically cooled fuel targets is overviewed in the present paper. The fabrication development was initiated as a part of the Fast Ignition Realization Experiment (FIREX) Project at the ILE, Osaka University in the way of bilateral collaboration between Osaka University and National Institute for Fusion Science (NIFS). A foam cryogenic target was designed where low-density foam shells with a conical light guide will be cooled down to the cryogenic temperature and will be fueled through a narrow pipe. The required diameter and thickness of the capsule are 500 μm and 20 μm, respectively. The material should be low-density plastics foam. We have prepared such capsules using 1) mixtureing a new material of (phloroglucinolcarboxylic acid)/formalin (PF) linear polymer to control kinematic viscosity of the precursor, 2) phase-transfer-catalyzed gelation process to keep density matching of three phases of the emulsion. 3) non-volatile silicone oil as outer oil of emulsion in order to prevent hazard halogenated hydrocarbon and flammable mineral oil. The obtained foam capsule had fine structure of 180 nm (outer surface) to 220 nm (inner surface) and uniform thickness reaching to resolution limit of optical analysis (∼0.5 μm). A small hole was made before the solvent exchange and the drying process to prevent distortion due to volume changes. The density of dried foam was 0.29 g/cm 3 . After attaching the petawatt laser guiding cone and fueling glass tube, poly([2,2]paracyclophane) was coated on the foam surface and supplied for a fueling test of cryogenic hydrogen. Generally, lower density is from larger pore, then precise control of thickness and its encapsulation becomes more difficult. We have clarified the relation between pore size and preparation conditions using several precursor materials, and revealed how to control pore size of low density foams, where the solvent affinity for the polymer chain plays fundamental

  9. Stability of Ignition Transients

    OpenAIRE

    V.E. Zarko

    1991-01-01

    The problem of ignition stability arises in the case of the action of intense external heat stimuli when, resulting from the cut-off of solid substance heating, momentary ignition is followed by extinction. Physical pattern of solid propellant ignition is considered and ignition criteria available in the literature are discussed. It is shown that the above mentioned problem amounts to transient burning at a given arbitrary temperature distribution in the condensed phase. A brief survey...

  10. Progress Towards Ignition on the National Ignition Facility

    Science.gov (United States)

    Edwards, John

    2012-10-01

    Since completion of the National Ignition Facility (NIF) construction project in March 2009, a wide variety of diagnostics, facility infrastructure, and experimental platforms have been commissioned in pursuit of generating the conditions necessary to reach thermonuclear ignition in the laboratory via the inertial confinement approach. NIF's capabilities and infrastructure include over 50 X-ray, optical, and nuclear diagnostics systems and the ability to shoot cryogenic DT layered capsules. There are two main approaches to ICF: direct drive in which laser light impinges directly on a capsule containing a solid layer of DT fuel, and indirect drive in which the laser light is first converted to thermal X-rays. To date NIF has been conducting experiments using the indirect drive approach, injecting up to 1.8MJ of ultraviolet light (0.35 micron) into 1 cm scale cylindrical gold or gold-coated uranium, gas-filled hohlraums, to implode 1mm radius plastic capsules containing solid DT fuel layers. In order to achieve ignition conditions the implosion must be precisely controlled. The National Ignition Campaign (NIC), an international effort with the goal of demonstrating thermonuclear burn in the laboratory, is making steady progress toward this. Utilizing precision pulse-shaping experiments in early 2012 the NIC achieve fuel rhoR of approximately 1.2 gm/cm^2 with densities of around 600-800 g/cm^3 along with neutron yields within about a factor of 5 necessary to enter a regime in which alpha particle heating will become important. To achieve these results, experimental platforms were developed to carefully control key attributes of the implosion. This talk will review NIF's capabilities and the progress toward ignition, as well as the physics of ignition targets on NIF and on other facilities. Acknowledgement: this work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  11. Ignition experiment in a single-turn-coil tokamak

    International Nuclear Information System (INIS)

    Carrera, R.; Driga, M.; Gully, J.H.

    1989-01-01

    A novel concept for a fusion ignition experiment, IGNITEX proposed along the lines of previous ideas for a compact thermonuclear device is analyzed. A single-turn-coil tokamak is analyzed. A single-turn-coil tokamak supplied by homopolar generators can ohmically heat a DT plasma to ignition conditions and maintain a thermally stable ignited phase for about ten energy confinement times. The IGNITEX experiment can provide a simple and relatively inexpensive way to produce and control ignited plasmas for scientific study

  12. Dual coil ignition system

    Energy Technology Data Exchange (ETDEWEB)

    Huberts, Garlan J.; Qu, Qiuping; Czekala, Michael Damian

    2017-03-28

    A dual coil ignition system is provided. The dual coil ignition system includes a first inductive ignition coil including a first primary winding and a first secondary winding, and a second inductive ignition coil including a second primary winding and a second secondary winding, the second secondary winding connected in series to the first secondary winding. The dual coil ignition system further includes a diode network including a first diode and a second diode connected between the first secondary winding and the second secondary winding.

  13. AutoCAD workbook

    CERN Document Server

    Metherell, Phil

    1989-01-01

    AutoCAD Workbook helps new users learn the basics of AutoCad, providing guidance on most of the commonly used functions in which the program operates.This book discusses loading AutoCad and starting a drawing; drawing and erasing lines, circles, and arcs; and setting up the drawing environment. The topics on drawing and editing polylines; entering text and text styles; and layers, linetype, and color are also considered. This publication likewise covers creating and using blocks, hatching and extracting information, dimensioning drawings, 3D visualization, and plotting a drawing. Other

  14. Fusion ignition via a magnetically-assisted fast ignition approach

    OpenAIRE

    Wang, W. -M.; Gibbon, P.; Sheng, Z. -M.; Li, Y. T.; Zhang, J.

    2016-01-01

    Significant progress has been made towards laser-driven fusion ignition via different schemes, including direct and indirect central ignition, fast ignition, shock ignition, and impact ignition schemes. However, to reach ignition conditions, there are still various technical and physical challenges to be solved for all these schemes. Here, our multi-dimensional integrated simulation shows that the fast-ignition conditions could be achieved when two 2.8 petawatt heating laser pulses counter-pr...

  15. Tagaotsitav "Auto" / Kristiina Vaarik

    Index Scriptorium Estoniae

    Vaarik, Kristiina

    2001-01-01

    Chris O'Connelli "Auto" Vanemuises, lavastaja Mark Babych. Etendusele tegid muusika ansamblist Bizarre tuntud muusikud Tristan Priimägi ja Lauri Liivak, kes artiklis sellest räägivad. Esietendus 2. detsembril 2000

  16. Spike frequency adaptation is a possible mechanism for control of attractor preference in auto-associative neural networks

    Science.gov (United States)

    Roach, James; Sander, Leonard; Zochowski, Michal

    Auto-associative memory is the ability to retrieve a pattern from a small fraction of the pattern and is an important function of neural networks. Within this context, memories that are stored within the synaptic strengths of networks act as dynamical attractors for network firing patterns. In networks with many encoded memories, some attractors will be stronger than others. This presents the problem of how networks switch between attractors depending on the situation. We suggest that regulation of neuronal spike-frequency adaptation (SFA) provides a universal mechanism for network-wide attractor selectivity. Here we demonstrate in a Hopfield type attractor network that neurons minimal SFA will reliably activate in the pattern corresponding to a local attractor and that a moderate increase in SFA leads to the network to converge to the strongest attractor state. Furthermore, we show that on long time scales SFA allows for temporal sequences of activation to emerge. Finally, using a model of cholinergic modulation within the cortex we argue that dynamic regulation of attractor preference by SFA could be critical for the role of acetylcholine in attention or for arousal states in general. This work was supported by: NSF Graduate Research Fellowship Program under Grant No. DGE 1256260 (JPR), NSF CMMI 1029388 (MRZ) and NSF PoLS 1058034 (MRZ & LMS).

  17. A Novel Therapy for Chronic Sleep-Onset Insomnia: A Retrospective, Nonrandomized Controlled Study of Auto-Adjusting, Dual-Level, Positive Airway Pressure Technology.

    Science.gov (United States)

    Krakow, Barry; Ulibarri, Victor A; McIver, Natalia D; Nadorff, Michael R

    2016-09-29

    Evidence indicates that behavioral or drug therapy may not target underlying pathophysiologic mechanisms for chronic insomnia, possibly due to previously unrecognized high rates (30%-90%) of sleep apnea in chronic insomnia patients. Although treatment studies with positive airway pressure (PAP) demonstrate decreased severity of chronic sleep maintenance insomnia in patients with co-occurring sleep apnea, sleep-onset insomnia has not shown similar results. We hypothesized advanced PAP technology would be associated with decreased sleep-onset insomnia severity in a sample of predominantly psychiatric patients with comorbid sleep apnea. We reviewed charts of 74 severe sleep-onset insomnia patients seen from March 2011 to August 2015, all meeting American Academy of Sleep Medicine Work Group criteria for a chronic insomnia disorder and all affirming behavioral and psychological origins for insomnia (averaging 10 of 18 indicators/patient), as well as averaging 2 or more psychiatric symptoms or conditions: depression (65.2%), anxiety (41.9%), traumatic exposure (35.1%), claustrophobia (29.7%), panic attacks (28.4%), and posttraumatic stress disorder (20.3%). All patients failed continuous or bilevel PAP and were manually titrated with auto-adjusting PAP modes (auto-bilevel and adaptive-servo ventilation). At 1-year follow-up, patients were compared through nonrandom assignment on the basis of a PAP compliance metric of > 20 h/wk (56 PAP users) versus insomnia severity (Hedges' g = 1.72) and sleep-onset insomnia (g = 2.07) compared to partial users (g = 1.04 and 0.91, respectively). Both global and sleep-onset insomnia severity decreased below moderate levels in PAP users compared to partial users whose outcomes persisted at moderately severe levels. In a nonrandomized controlled retrospective study, advanced PAP technology (both auto-bilevel and adaptive servo-ventilation) were associated with large decreases in insomnia severity for sleep-onset insomnia patients who

  18. Development of ATSR (Auto Thermal Steam Reformer)

    International Nuclear Information System (INIS)

    Ono, J.; Yoshino, Y.; Kuwabara, T.; Fujisima, S.; Kobayashi, S.; Maruko, S.

    2004-01-01

    'Full text:' Auto-thermal reformers are used popularly for fuel cell vehicle because they are compact and can start up quickly. On the other hand, steam reformers are used for stationary fuel cell power plant because they are good thermal efficiency. While, there are many cases using the auto- thermal reformer for stationary use with expectation of cost reduction in USA, as well. However, they are still insufficient for its durability, compactness and cost. We have been developing the new type of fuel processing system that is auto-thermal steam reformer (ATSR), which is hybrid of a conventional steam reformer (STR) and a conventional auto-thermal reformer (ATR). In this study, some proto-type of ATSR for field test were designed, tried manufacturing and tested performance and durability. And we have tried to operate with fuel cell stack to evaluate the system interface performance, that is, operability and controllability. (author)

  19. Application of Auto CAD 2000

    International Nuclear Information System (INIS)

    Kim, Hyeong Jun

    1999-11-01

    This book deals with basic of AutoCAD, beginning AutoCAD 2000, using design center of AutoCAD 2000, adding drawing element with design center, drawing lines, using 2D edit command, making layer, hatching, dimensioning, entering letters on the floor plan, making 3D object, practice of 3D command, edition of 3D object, making solid, rendering object, and using internet in AutoCAD 2000. This book is introduction of AutoCAD 2000 for beginner.

  20. Multi variable control of a switched ignition device: efficiency improvement under various constraints; Commande multivariable d`un moteur a allumage commande: Amelioration du rendement sous differentes contraintes

    Energy Technology Data Exchange (ETDEWEB)

    Chaumerliac, V

    1995-03-09

    Spark-ignition engine control needs substantial improvement for various reasons: a non-linear and multivariable process, the strictness of anti-pollution constraints, the necessity of fuel economy, the variable running conditions, the aging, the reliability and the cost. The improvement of engine efficiency will be involved in this context and with the pollution constraints. This work develops a system approach and its philosophy is based on a suitable description of the main dynamics. A compartmentalized model of a spark-ignition engine and the dynamic of the vehicle is presented. The aim of this modeling is to have a good representativeness in transients and to describe the behavior of the outputs useful for control. The multivariable control is split in two independent systems. The first one controls the spark advance control to obtain the maximum torque. The second one controls the throttle and the electronic fuel injection device to have lower pollutant emissions. The spark advance closed loop control uses information measured with either a cylinder pressure sensor or a torque sensor. These studies have achieved to an adaptive tuning on engine bench. A new actuator, the electronic throttle control, can provide a higher degree of precision for the fuel/air ratio regulation system, particularly during fast accelerations and decelerations. An intake manifold pressure control is developed to coordinate the air and fuel flows. A delay strategy and a simple compensation of fuel supply dynamics allow to obtain good results on engine bench. Uncoupling the acceleration pedal and the throttle command is a promising way to improve engine efficiency and reduce exhaust emission during transient phases. (author) 59 refs.

  1. Genotoxic damage in auto body shop workers.

    Science.gov (United States)

    Siebel, Anna Maria; Basso da Silva, Luciano

    2010-10-01

    Some studies have shown increased DNA damage among car painters, but other professionals working in auto body and paint shops have not been extensively assessed. The aim of this study was to assess DNA damage in different types of auto body shop workers by measuring micronucleus (MN) levels in exfoliated buccal cells. The mean number of cells with MN per 2000 exfoliated buccal cells was analyzed in three groups of male workers: auto body repair technicians, painters, and office workers (control group). All participants answered a questionnaire inquiring about age, smoking habits, alcohol consumption, work practices, occupational exposure time, job activities, and use of protective equipment. The mean number of cells with MN was 3.50 ± 1.50 in auto body painters, 3.91 ± 2.10 in auto body repair technicians, and 0.80 ± 0.78 in office workers, with a significant difference between the control group and the two other groups (p = 0.0001). Age, occupational exposure time, use of protective masks, alcohol consumption, and smoking habit did not affect MN results. The findings indicate that technicians and painters working in auto body shops are at risk for genotoxic damage, while office workers seem to be protected.

  2. Ignition in Convective-Diffusive Systems

    National Research Council Canada - National Science Library

    Law, Chung

    1999-01-01

    ... efficiency as well as the knock and emission characteristics. The ignition event is clearly controlled by the chemical reactions of fuel oxidation and the fluid mechanics of convective and diffusive transport...

  3. A comparative experimental study on engine operating on premixed charge compression ignition and compression ignition mode

    Directory of Open Access Journals (Sweden)

    Bhiogade Girish E.

    2017-01-01

    Full Text Available New combustion concepts have been recently developed with the purpose to tackle the problem of high emissions level of traditional direct injection Diesel engines. A good example is the premixed charge compression ignition combustion. A strategy in which early injection is used causing a burning process in which the fuel burns in the premixed condition. In compression ignition engines, soot (particulate matter and NOx emissions are an extremely unsolved issue. Premixed charge compression ignition is one of the most promising solutions that combine the advantages of both spark ignition and compression ignition combustion modes. It gives thermal efficiency close to the compression ignition engines and resolves the associated issues of high NOx and particulate matter, simultaneously. Premixing of air and fuel preparation is the challenging part to achieve premixed charge compression ignition combustion. In the present experimental study a diesel vaporizer is used to achieve premixed charge compression ignition combustion. A vaporized diesel fuel was mixed with the air to form premixed charge and inducted into the cylinder during the intake stroke. Low diesel volatility remains the main obstacle in preparing premixed air-fuel mixture. Exhaust gas re-circulation can be used to control the rate of heat release. The objective of this study is to reduce exhaust emission levels with maintaining thermal efficiency close to compression ignition engine.

  4. Hot Surface Ignition

    OpenAIRE

    Tursyn, Yerbatyr; Goyal, Vikrant; Benhidjeb-Carayon, Alicia; Simmons, Richard; Meyer, Scott; Gore, Jay P.

    2015-01-01

    Undesirable hot surface ignition of flammable liquids is one of the hazards in ground and air transportation vehicles, which primarily occurs in the engine compartment. In order to evaluate the safety and sustainability of candidate replacement fuels with respect to hot surface ignition, a baseline low lead fuel (Avgas 100 LL) and four experimental unleaded aviation fuels recommended for reciprocating aviation engines were considered. In addition, hot surface ignition properties of the gas tu...

  5. Exhaust gas recirculation in a homogeneous charge compression ignition engine

    Science.gov (United States)

    Duffy, Kevin P [Metamora, IL; Kieser, Andrew J [Morton, IL; Rodman, Anthony [Chillicothe, IL; Liechty, Michael P [Chillicothe, IL; Hergart, Carl-Anders [Peoria, IL; Hardy, William L [Peoria, IL

    2008-05-27

    A homogeneous charge compression ignition engine operates by injecting liquid fuel directly in a combustion chamber, and mixing the fuel with recirculated exhaust and fresh air through an auto ignition condition of the fuel. The engine includes at least one turbocharger for extracting energy from the engine exhaust and using that energy to boost intake pressure of recirculated exhaust gas and fresh air. Elevated proportions of exhaust gas recirculated to the engine are attained by throttling the fresh air inlet supply. These elevated exhaust gas recirculation rates allow the HCCI engine to be operated at higher speeds and loads rendering the HCCI engine a more viable alternative to a conventional diesel engine.

  6. The Auto control System Based on InTouch Configuration software for High-gravity Oil Railway Tank Feeding

    Directory of Open Access Journals (Sweden)

    Xu De-Kai

    2015-01-01

    Full Text Available This paper provides automatic design for high-gravity oil railway tank feeding system of some refinery uses distributive control system. The system adopts the automatic system of Modicon TSX Quantum or PLC as monitor and control level and uses a PC-based plat form as principal computer running on the Microsoft Windows2000. An automatic control system is developed in the environment of InTouch configuration software. This system implements automatic high-gravity oil tank feeding with pump controlling function. And it combines automatic oil feeding controlling, pump controlling and tank monitoring function to implement the automation of oil feeding with rations and automatic control.

  7. Study of the Injection Control Strategies of a Compression Ignition Free Piston Engine Linear Generator in a One-Stroke Starting Process

    Directory of Open Access Journals (Sweden)

    Huihua Feng

    2016-06-01

    Full Text Available For a compression ignition (CI free piston engine linear generator (FPLG, injection timing is one of the most important parameters that affect its performance, especially for the one-stroke starting operation mode. In this paper, two injection control strategies are proposed using piston position and velocity signals. It was found experimentally that the injection timing’s influence on the compression ratio, the peak in-cylinder gas pressure and the indicated work (IW is different from that of traditional reciprocating CI engines. The maximum IW of the ignition starting cylinder, say left cylinder (LC and the right cylinder (RC are 132.7 J and 138.1 J, respectively. The thermal-dynamic model for simulating the working processes of the FPLG are built and verified by experimental results. The numerical simulation results show that the running instability and imbalance between LC and RC are the obvious characters when adopting the injection strategy of the velocity feedback. These could be solved by setting different triggering velocity thresholds for the two cylinders. The IW output from the FPLG under this strategy is higher than that of adopting the position feedback strategy, and the maximum IW of the RC could reach 162.3 J. Under this strategy, the prototype is able to achieve better starting conditions and could operate continuously for dozens of cycles.

  8. Reaching ignition in the tokamak

    International Nuclear Information System (INIS)

    Furth, H.P.

    1985-06-01

    This review covers the following areas: (1) the physics of burning plasmas, (2) plasma physics requirements for reaching ignition, (3) design studies for ignition devices, and (4) prospects for an ignition project

  9. Approach to ignition of tokamak reactors

    International Nuclear Information System (INIS)

    Sigmar, D.J.

    1981-02-01

    Recent transport modeling results for JET, INTOR, and ETF are reviewed and analyzed with respect to existing uncertainties in the underlying physics, the self-consistency of the very large numerical codes, and the margin for ignition. The codes show ignition to occur in ETF/INTOR-sized machines if empirical scaling can be extrapolated to ion temperatures (and beta values) much higher than those presently achieved, if there is no significant impurity accumulation over the first 7 s, and if the known ideal and resistive MHD instabilities remain controllable for the evolving plasma profiles during ignition startup

  10. An assessment of the dual-mode reactivity controlled compression ignition/conventional diesel combustion capabilities in a EURO VI medium-duty diesel engine fueled with an intermediate ethanol-gasoline blend and biodiesel

    International Nuclear Information System (INIS)

    Benajes, Jesús; García, Antonio; Monsalve-Serrano, Javier; Balloul, Iyad; Pradel, Gérard

    2016-01-01

    Highlights: • Reactivity controlled compression ignition regime utilized from 25% to 35% load. • Dual-mode reduces the regeneration periods of the diesel particulate filter. • The use of near-term available biofuels allows good performance and emissions. • Dual-mode leads to 2% greater efficiency than diesel combustion at high engine speeds. - Abstract: This work investigates the capabilities of the dual-mode reactivity controlled compression ignition/conventional diesel combustion engine operation to cover the full operating range of a EURO VI medium-duty diesel engine with compression ratio of 17.5:1. This concept is based on covering all the engine map switching between the reactivity controlled compression ignition and the conventional diesel combustion operating modes. Specifically, the benefits of reactivity controlled compression ignition combustion are exploited whenever possible according to certain restrictions, while the conventional diesel combustion operation is used to cover the zones of the engine map in which the reactivity controlled compression ignition operation is limited. The experiments were conducted using a single-cylinder research diesel engine derived from the multi-cylinder production engine. In addition, considering the mandatory presence of biofuels in the future context of road transport and the ability of ethanol to be blended with gasoline, the low reactivity fuel used in the study is a blend of 20% ethanol by volume with 80% of 95 octane number gasoline. Moreover, a diesel containing 7% of biodiesel has been used as high reactivity fuel. Firstly, a reactivity controlled compression ignition mapping is performed to check the operational limits of the concept in this engine platform. Later, based on the results, the potential of the dual-mode concept is discussed. Results suggest that, under the constraints imposed, reactivity controlled compression ignition combustion can be utilized between 25% and 35% load. In this region

  11. Control and diagnosis oriented modelling of the compression ignition engine; Modelisation du moteur a allumage par compression dans la perspective du controle et du diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Grondin, O

    2004-12-15

    This thesis has described an investigation into the modelling of compression ignition engine for control and diagnosis purpose. The Diesel engine is the most efficient and clean internal combustion engine due to modem electromechanical actuators. However, pollutant emission regulations are much more stricter, thus, these complex systems need sophisticated and efficient control algorithms to reach very low emission levels. For this task, engine models are required at each step of the control system development: control laws synthesis, simulation and validation. The system under study is a six cylinder direct injection Diesel engine fitted with a turbocharger. The model of this system is based on physical laws for some parts of the engine such as cylinders, manifolds, turbocharger and crank-slider system. In order to reduce computing time we choose to model heat transfer and heat release during combustion using simple empirical correlations. Resulting model has been implemented in the Matlab-Simulink environment and it can predict variables of interest for control purpose with one degree crank angle resolution. The model has been tested numerically and compared with an industrial engine simulation code with good results. Moreover, model output variables are in good agreement with experimental data recorded on a heavy-duty research engine. The engine model has been embedded on a board providing enough computing performances to perform real-time simulations, this will be helpful for 'hardware-in-the-loop' simulations. Another part of this study is dedicated to the combustion process modelling using a non linear phenomenological model: the NARMAX model. The goal is to predict the in-cylinder pressure evolution using other measurements available on the engine. The NARMAX model parameters have been identified using input-output data carried out from the experimental engine. Such model is well suited for real-time applications compare to numerically cost effective physical

  12. Control and diagnosis oriented modelling of the compression ignition engine; Modelisation du moteur a allumage par compression dans la perspective du controle et du diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Grondin, O.

    2004-12-15

    This thesis has described an investigation into the modelling of compression ignition engine for control and diagnosis purpose. The Diesel engine is the most efficient and clean internal combustion engine due to modem electromechanical actuators. However, pollutant emission regulations are much more stricter, thus, these complex systems need sophisticated and efficient control algorithms to reach very low emission levels. For this task, engine models are required at each step of the control system development: control laws synthesis, simulation and validation. The system under study is a six cylinder direct injection Diesel engine fitted with a turbocharger. The model of this system is based on physical laws for some parts of the engine such as cylinders, manifolds, turbocharger and crank-slider system. In order to reduce computing time we choose to model heat transfer and heat release during combustion using simple empirical correlations. Resulting model has been implemented in the Matlab-Simulink environment and it can predict variables of interest for control purpose with one degree crank angle resolution. The model has been tested numerically and compared with an industrial engine simulation code with good results. Moreover, model output variables are in good agreement with experimental data recorded on a heavy-duty research engine. The engine model has been embedded on a board providing enough computing performances to perform real-time simulations, this will be helpful for 'hardware-in-the-loop' simulations. Another part of this study is dedicated to the combustion process modelling using a non linear phenomenological model: the NARMAX model. The goal is to predict the in-cylinder pressure evolution using other measurements available on the engine. The NARMAX model parameters have been identified using input-output data carried out from the experimental engine. Such model is well suited for real-time applications compare to numerically cost

  13. AutoCAD

    DEFF Research Database (Denmark)

    Jensen, Henrik

    1998-01-01

    I 1998 var AutoCAD Arkitektskolens basale CAD-tilbud til de studerende. Kursets vægt ligger på konstruktion og strukturering af 3d-modeller og med udgangspunkt i dette, 2d-tegning. Kurset er opbygget over CAD Clasic skabelonen (se min forskning). Kompendiet kan bruges til selvstudium.......I 1998 var AutoCAD Arkitektskolens basale CAD-tilbud til de studerende. Kursets vægt ligger på konstruktion og strukturering af 3d-modeller og med udgangspunkt i dette, 2d-tegning. Kurset er opbygget over CAD Clasic skabelonen (se min forskning). Kompendiet kan bruges til selvstudium....

  14. PERI auto-tuning

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, D H; Williams, S [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Chame, J; Chen, C; Hall, M [USC/ISI, Marina del Rey, CA 90292 (United States); Dongarra, J; Moore, S; Seymour, K; You, H [University of Tennessee, Knoxville, TN 37996 (United States); Hollingsworth, J K; Tiwari, A [University of Maryland, College Park, MD 20742 (United States); Hovland, P; Shin, J [Argonne National Laboratory, Argonne, IL 60439 (United States)], E-mail: mhall@isi.edu

    2008-07-15

    The enormous and growing complexity of today's high-end systems has increased the already significant challenges of obtaining high performance on equally complex scientific applications. Application scientists are faced with a daunting challenge in tuning their codes to exploit performance-enhancing architectural features. The Performance Engineering Research Institute (PERI) is working toward the goal of automating portions of the performance tuning process. This paper describes PERI's overall strategy for auto-tuning tools and recent progress in both building auto-tuning tools and demonstrating their success on kernels, some taken from large-scale applications.

  15. Ignition probabilities for Compact Ignition Tokamak designs

    International Nuclear Information System (INIS)

    Stotler, D.P.; Goldston, R.J.

    1989-09-01

    A global power balance code employing Monte Carlo techniques had been developed to study the ''probability of ignition'' and has been applied to several different configurations of the Compact Ignition Tokamak (CIT). Probability distributions for the critical physics parameters in the code were estimated using existing experimental data. This included a statistical evaluation of the uncertainty in extrapolating the energy confinement time. A substantial probability of ignition is predicted for CIT if peaked density profiles can be achieved or if one of the two higher plasma current configurations is employed. In other cases, values of the energy multiplication factor Q of order 10 are generally obtained. The Ignitor-U and ARIES designs are also examined briefly. Comparisons of our empirically based confinement assumptions with two theory-based transport models yield conflicting results. 41 refs., 11 figs

  16. Effects of auto-servo ventilation on patients with sleep-disordered breathing, stable systolic heart failure and concomitant diastolic dysfunction: subanalysis of a randomized controlled trial.

    Science.gov (United States)

    Birner, Christoph; Series, Frederic; Lewis, Keir; Benjamin, Amit; Wunderlich, Silke; Escourrou, Pierre; Zeman, Florian; Luigart, Ruth; Pfeifer, Michael; Arzt, Michael

    2014-01-01

    Systolic heart failure (HF) is frequently accompanied by diastolic dysfunction and sleep-disordered breathing (SDB). The objective of this subset analysis was to determine effect sizes of auto-servo ventilation (ASV and biphasic positive airway pressure ASV) on echocardiographic measures of diastolic function in patients with systolic HF and SDB. Thirty-two patients with stable systolic HF, concomitant diastolic dysfunction [age 66 ± 9 years old, left ventricular (LV) ejection fraction: 30 ± 7% and New York Heart Association class II: 72%] and SDB (apnea-hypopnea index, AHI: 48 ± 19/h; 53% had predominantly obstructive sleep apnea) receiving either ASV (n = 19) or optimal medical treatment (control, n = 13) were analyzed in a randomized controlled clinical trial. Polysomnographic and echocardiographic measurements were obtained at baseline and after 12 weeks. AHI significantly improved in the ASV group compared to the control group (-39 ± 18 vs. -0.2 ± 13.2/h, p control visit, diastolic function assessed by the isovolumetric relaxation time (-10.3 ± 26.1 vs. 9.3 ± 49.1, p = 0.48) and deceleration time (-43.9 ± 88.8 vs. 12.4 ± 68.8, p = 0.40) tended to improve after ASV treatment, but did not reach statistical significance. Likewise, the proportion of patients whose diastolic dysfunction improved was nonsignificantly higher in the ASV than in the control group, respectively (37 vs. 15%, p = 0.25). ASV treatment efficiently abolishes SDB in patients with stable systolic HF and concomitant diastolic dysfunction, and was associated with a statistically nonsignificant improvement in measures of diastolic dysfunction. Thus, these data provide estimates of effect size and justify the evaluation of the effects of ASV on diastolic function in larger randomized controlled trials. Copyright © 2013 S. Karger AG, Basel.

  17. Ignition tuning for the National Ignition Campaign

    Directory of Open Access Journals (Sweden)

    Landen O.

    2013-11-01

    Full Text Available The overall goal of the indirect-drive inertial confinement fusion [1] tuning campaigns [2] is to maximize the probability of ignition by experimentally correcting for likely residual uncertainties in the implosion and hohlraum physics [3] used in our radiation-hydrodynamic computational models, and by checking for and resolving unexpected shot-to-shot variability in performance [4]. This has been started successfully using a variety of surrogate capsules that set key laser, hohlraum and capsule parameters to maximize ignition capsule implosion velocity, while minimizing fuel adiabat, core shape asymmetry and ablator-fuel mix.

  18. The Durban Auto Cluster

    DEFF Research Database (Denmark)

    Lorentzen, Jochen; Robbins, Glen; Barnes, Justin

    2004-01-01

    The paper describes the formation of the Durban Auto Cluster in the context of trade liberalization. It argues that the improvement of operational competitiveness of firms in the cluster is prominently due to joint action. It tests this proposition by comparing the gains from cluster activities...

  19. AUTO-EXPANSIVE FLOW

    Science.gov (United States)

    Physics suggests that the interplay of momentum, continuity, and geometry in outward radial flow must produce density and concomitant pressure reductions. In other words, this flow is intrinsically auto-expansive. It has been proposed that this process is the key to understanding...

  20. Effects of air jet duration and timing on the combustion characteristics of high-pressure air jet controlled compression ignition combustion mode in a hybrid pneumatic engine

    International Nuclear Information System (INIS)

    Long, Wuqiang; Meng, Xiangyu; Tian, Jiangping; Tian, Hua; Cui, Jingchen; Feng, Liyan

    2016-01-01

    Highlights: • A 3-D CFD model of the power cylinder in HPE was developed. • High-pressure air JCCI combustion mode includes two-stage high-temperature reaction. • The combustion phasing of the pre-mixture is controllable via the SOJ timing. • There exists an optimum SOJ timing for obtaining the highest combustion efficiency and shortest burning duration. - Abstract: The high-pressure air jet controlled compression ignition (JCCI) combustion mode was employed to control the premixed diesel compression ignition combustion phasing by using the compound thermodynamic cycle under all operating conditions, which is accomplished in a hybrid pneumatic engine (HPE). A three-dimensional computational fluid dynamics (CFD) numerical simulation coupled with reduced n-heptane chemical kinetics mechanism has been applied to investigate the effects of high-pressure air jet duration and the start of jet (SOJ) timing on the combustion characteristics in the power cylinder of HPE. By sweeping the high-pressure air jet durations from 6 to 14 °CA and SOJ timings from −12 °CA ATDC to the top dead center (TDC) under the air jet temperatures of 400 and 500 K, respectively, the low- and high-temperature reactions, combustion efficiency, as well as the combustion phasing and burning duration have been analyzed in detail. The results illustrated that a longer air jet duration results in a higher peak in the first-stage high-temperature reaction, and the short air jet duration of 6 °CA can lead to a higher combustion efficiency. The SOJ timing sweep results showed that there exists an optimum timing for obtaining the highest combustion efficiency and shortest burning duration.

  1. AutoCAD 2014 and AutoCAD LT 2014

    CERN Document Server

    Gladfelter, Donnie

    2013-01-01

    A step-by-step tutorial introduction to AutoCAD As the only book to teach AutoCAD using a continuous tutorial which allows you to follow along sequentially or jump in at any exercise by downloading the drawing files, this Autodesk Official Press book is ideal for the AutoCAD novice. Industry expert and AutoCAD guru Donnie Gladfelter walks you through the powerful features of AutoCAD, provides you with a solid foundation of the basics, and shares the latest industry standards and techniques. The hands-on tutorial project inspired by real-world workflows that runs throughout the book

  2. Antiknock quality and ignition kinetics of 2-phenylethanol, a novel lignocellulosic octane booster

    KAUST Repository

    Shankar, Vijai

    2016-06-28

    High-octane quality fuels are important for increasing spark ignition engine efficiency, but their production comes at a substantial economic and environmental cost. The possibility of producing high anti-knock quality gasoline by blending high-octane bio-derived components with low octane naphtha streams is attractive. 2-phenyl ethanol (2-PE), is one such potential candidate that can be derived from lignin, a biomass component made of interconnected aromatic groups. We first ascertained the blending anti-knock quality of 2-PE by studying the effect of spark advancement on knock for various blends 2-PE, toluene, and ethanol with naphtha in a cooperative fuels research engine. The blending octane quality of 2-PE indicated an anti-knock behavior similar or slightly greater than that of toluene, and ethylbenzene, which could be attributed to either chemical kinetics or charge cooling effects. To isolate chemical kinetic effects, a model for 2-PE auto-ignition was developed and validated using ignition delay times measured in a high-pressure shock tube. Simulated ignition delay times of 2-PE were also compared to those of traditional high-octane gasoline blending components to show that the gas phase reactivity of 2-PE is lower than ethanol, and comparable to toluene, and ethylbenzene at RON, and MON relevant conditions. The gas-phase reactivity of 2-PE is largely controlled by its aromatic ring, while the effect of the hydroxyl group is minimal. The higher blending octane quality of 2-PE compared to toluene, and ethylbenzene can be attributed primarily to the effect of the hydroxyl group on increasing heat of vaporization. © 2016 The Combustion Institute.

  3. Effect of main injection timing for controlling the combustion phasing of a homogeneous charge compression ignition engine using a new dual injection strategy

    International Nuclear Information System (INIS)

    Das, Pranab; Subbarao, P.M.V.; Subrahmanyam, J.P.

    2015-01-01

    Highlights: • A new dual injection concept is developed by minimum geometry modification. • The occurrence of combustion parameters strongly depend on main injection timing. • At higher load, premixed equivalence ratio dominates over main injection timing. • Retarded of main injection timing tends to retard combustion phasing. • Slightly retarded main injection timing is recommended to avoid intense knocking. - Abstract: Homogeneous charge compression ignition combustion of diesel fuel is implemented using a novel dual injection strategy. A new experimental technique is developed to modify a single cylinder direct injection diesel engine to run on homogeneous combustion mode. Effect of main injection timing is investigated covering a range from 26 to 8 crank angle degrees before top dead center with an interval of 3°. Retarded main injection timing is identified as a control strategy for delaying combustion phasing and a means of controlled combustion phasing of direct injection homogeneous charge compression ignition combustion. Two load conditions were investigated and it was observed that at higher load, start of combustion depends more on fuel air equivalence ratio than main injection timing, whereas at low load, it significantly varies with varying main injection timing. Significant improvements in smoke and oxides of nitrogen emissions are observed when compared with the baseline conventional combustion. By studying different combustion parameters, it is observed that there is an improvement in performance and emissions with marginal loss in thermal efficiency when the main injection timing is 20° before top dead center. This is identified as the optimum main injection timing for such homogeneous combustion under the same operating condition

  4. Effects of Direct Fuel Injection Strategies on Cycle-by-Cycle Variability in a Gasoline Homogeneous Charge Compression Ignition Engine: Sample Entropy Analysis

    Directory of Open Access Journals (Sweden)

    Jacek Hunicz

    2015-01-01

    Full Text Available In this study we summarize and analyze experimental observations of cyclic variability in homogeneous charge compression ignition (HCCI combustion in a single-cylinder gasoline engine. The engine was configured with negative valve overlap (NVO to trap residual gases from prior cycles and thus enable auto-ignition in successive cycles. Correlations were developed between different fuel injection strategies and cycle average combustion and work output profiles. Hypothesized physical mechanisms based on these correlations were then compared with trends in cycle-by-cycle predictability as revealed by sample entropy. The results of these comparisons help to clarify how fuel injection strategy can interact with prior cycle effects to affect combustion stability and so contribute to design control methods for HCCI engines.

  5. An Instructional Method for the AutoCAD Modeling Environment.

    Science.gov (United States)

    Mohler, James L.

    1997-01-01

    Presents a command organizer for AutoCAD to aid new uses in operating within the 3-D modeling environment. Addresses analyzing the problem, visualization skills, nonlinear tools, a static view of a dynamic model, the AutoCAD organizer, environment attributes, and control of the environment. Contains 11 references. (JRH)

  6. Thermoplasmonic Ignition of Metal Nanoparticles.

    Science.gov (United States)

    Mutlu, Mehmet; Kang, Ju-Hyung; Raza, Søren; Schoen, David; Zheng, Xiaolin; Kik, Pieter G; Brongersma, Mark L

    2018-03-14

    Explosives, propellants, and pyrotechnics are energetic materials that can store and quickly release tremendous amounts of chemical energy. Aluminum (Al) is a particularly important fuel in many applications because of its high energy density, which can be released in a highly exothermic oxidation process. The diffusive oxidation mechanism (DOM) and melt-dispersion mechanism (MDM) explain the ways powders of Al nanoparticles (NPs) can burn, but little is known about the possible use of plasmonic resonances in NPs to manipulate photoignition. This is complicated by the inhomogeneous nature of powders and very fast heating and burning rates. Here, we generate Al NPs with well-defined sizes, shapes, and spacings by electron beam lithography and demonstrate that their plasmonic resonances can be exploited to heat and ignite them with a laser. By combining simulations with thermal-emission, electron-, and optical-microscopy studies, we reveal how an improved control over NP ignition can be attained.

  7. An iterative learning strategy for the auto-tuning of the feedforward and feedback controller in type-1 diabetes.

    Science.gov (United States)

    Fravolini, M L; Fabietti, P G

    2014-01-01

    This paper proposes a scheme for the control of the blood glucose in subjects with type-1 diabetes mellitus based on the subcutaneous (s.c.) glucose measurement and s.c. insulin administration. The tuning of the controller is based on an iterative learning strategy that exploits the repetitiveness of the daily feeding habit of a patient. The control consists of a mixed feedback and feedforward contribution whose parameters are tuned through an iterative learning process that is based on the day-by-day automated analysis of the glucose response to the infusion of exogenous insulin. The scheme does not require any a priori information on the patient insulin/glucose response, on the meal times and on the amount of ingested carbohydrates (CHOs). Thanks to the learning mechanism the scheme is able to improve its performance over time. A specific logic is also introduced for the detection and prevention of possible hypoglycaemia events. The effectiveness of the methodology has been validated using long-term simulation studies applied to a set of nine in silico patients considering realistic uncertainties on the meal times and on the quantities of ingested CHOs.

  8. MS AutoCad

    DEFF Research Database (Denmark)

    Andersen, Michael Rye; Heinicke, Hugo

    1996-01-01

    Formålet med dette notat er at give en introduktion til tegning af et generalarrangement ved anvendelse af CAD-programmet AutoCAD. Generalarrangementets formål er at skabe en overskuelig præsentation af et skibsprojekt. Det skal gøres indenfor de rammer, som ligger til grund for praktiskprojekter......Formålet med dette notat er at give en introduktion til tegning af et generalarrangement ved anvendelse af CAD-programmet AutoCAD. Generalarrangementets formål er at skabe en overskuelig præsentation af et skibsprojekt. Det skal gøres indenfor de rammer, som ligger til grund...

  9. Presença de auto-anticorpos não-tireóide-específicos no soro de pacientes com hipotireoidismo auto-imune

    OpenAIRE

    Soares Débora Vieira; Vanderborght Bart O. M.; Vaisman Mário

    2003-01-01

    Auto-anticorpos contra componentes não-específicos da tireóide foram encontrados no soro de pacientes com doença auto-imune da tireóide. Neste estudo avaliamos a presença de auto-anticorpos antinucleares (ANA), antimúsculo liso (anti-ML) e antimitocôndria (anti-Mc) no soro de pacientes com hipotireoidismo auto-imune (HA), comparando-os a controles saudáveis. Estudamos 70 pacientes com hipotireoidismo auto-imune (tireoidite de Hashimoto ou tireoidite atrófica ) e 70 controles saudáveis (sem di...

  10. Tritium and ignition target management at the National Ignition Facility.

    Science.gov (United States)

    Draggoo, Vaughn

    2013-06-01

    Isotopic mixtures of hydrogen constitute the basic fuel for fusion targets of the National Ignition Facility (NIF). A typical NIF fusion target shot requires approximately 0.5 mmoles of hydrogen gas and as much as 750 GBq (20 Ci) of 3H. Isotopic mix ratios are specified according to the experimental shot/test plan and the associated test objectives. The hydrogen isotopic concentrations, absolute amounts, gas purity, configuration of the target, and the physical configuration of the NIF facility are all parameters and conditions that must be managed to ensure the quality and safety of operations. An essential and key step in the preparation of an ignition target is the formation of a ~60 μm thick hydrogen "ice" layer on the inner surface of the target capsule. The Cryogenic Target Positioning System (Cryo-Tarpos) provides gas handling, cyro-cooling, x-ray imaging systems, and related instrumentation to control the volumes and temperatures of the multiphase (solid, liquid, and gas) hydrogen as the gas is condensed to liquid, admitted to the capsule, and frozen as a single spherical crystal of hydrogen in the capsule. The hydrogen fuel gas is prepared in discrete 1.7 cc aliquots in the LLNL Tritium Facility for each ignition shot. Post-shot hydrogen gas is recovered in the NIF Tritium Processing System (TPS). Gas handling systems, instrumentation and analytic equipment, material accounting information systems, and the shot planning systems must work together to ensure that operational and safety requirements are met.

  11. Research on cylinder processes of gasoline homogenous charge compression ignition (HCCI) engine

    Science.gov (United States)

    Cofaru, Corneliu

    2017-10-01

    This paper is designed to develop a HCCI engine starting from a spark ignition engine platform. The engine test was a single cylinder, four strokes provided with carburetor. The results of experimental research on this version were used as a baseline for the next phase of the work. After that, the engine was modified for a HCCI configuration, the carburetor was replaced by a direct fuel injection system in order to control precisely the fuel mass per cycle taking into account the measured intake air-mass. To ensure that the air - fuel mixture auto ignite, the compression ratio was increased from 9.7 to 11.5. The combustion process in HCCI regime is governed by chemical kinetics of mixture of air-fuel, rein ducted or trapped exhaust gases and fresh charge. To modify the quantities of trapped burnt gases, the exchange gas system was changed from fixed timing to variable valve timing. To analyze the processes taking place in the HCCI engine and synthesizing a control system, a model of the system which takes into account the engine configuration and operational parameters are needed. The cylinder processes were simulated on virtual model. The experimental research works were focused on determining the parameters which control the combustion timing of HCCI engine to obtain the best energetic and ecologic parameters.

  12. Treatment of sleep apnea in chronic heart failure patients with auto-servo ventilation improves sleep fragmentation: a randomized controlled trial.

    Science.gov (United States)

    Hetzenecker, Andrea; Escourrou, Pierre; Kuna, Samuel T; Series, Frederic; Lewis, Keir; Birner, Christoph; Pfeifer, Michael; Arzt, Michael

    2016-01-01

    Impaired sleep efficiency is independently associated with worse prognosis in patients with chronic heart failure (CHF). Therefore, a test was conducted on whether auto-servo ventilation (ASV, biphasic positive airway pressure [BiPAP]-ASV, Philips Respironics) reduces sleep fragmentation and improves sleep efficiency in CHF patients with central sleep apnea (CSA) or obstructive sleep apnea (OSA). In this multicenter, randomized, parallel group trial, a study was conducted on 63 CHF patients (age 64 ± 10 years; left ventricular ejection fraction 29 ± 7%) with CSA or OSA (apnea-hypopnea Index, AHI 47 ± 18/h; 46% CSA) referred to sleep laboratories of the four participating centers. Participants were randomized to either ASV (n = 32) or optimal medical treatment alone (control, n = 31). Polysomnography (PSG) and actigraphy at home (home) with centralized blinded scoring were obtained at baseline and 12 weeks. ASV significantly reduced sleep fragmentation (total arousal indexPSG: -16.4 ± 20.6 vs. -0.6 ± 13.2/h, p = 0.001; sleep fragmentation indexhome: -7.6 ± 15.6 versus 4.3 ± 13.9/h, p = 0.003, respectively) and significantly increased sleep efficiency assessed by actigraphy (SEhome) compared to controls (2.3 ± 10.1 vs. -2.1 ± 6.9%, p = 0.002). Effects of ASV on sleep fragmentation and efficiency were similar in patients suffering from OSA and CSA. At home, ASV treatment modestly improves sleep fragmentation as well as sleep efficiency in CHF patients having either CSA or OSA. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Acoustic Igniter, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — An acoustic igniter eliminates the need to use electrical energy to drive spark systems to initiate combustion in liquid-propellant rockets. It does not involve the...

  14. Progress of impact ignition

    International Nuclear Information System (INIS)

    Murakami, M.; Nagatomo, H.; Johzaki, T.

    2010-11-01

    In impact ignition scheme, a portion of the fuel (the impactor) is accelerated to a super-high velocity, compressed by convergence, and collided with a precompressed main fuel. This collision generates shock waves in both the impactor and the main fuel. Since the density of the impactor is generally much lower than that of the main fuel, the pressure balance ensures that the shock-heated temperature of the impactor is significantly higher than that of the main fuel. Hence, the impactor can reach ignition temperature and thus become an igniter. Here we report major new results on recent impact ignition research: (1) A maximum velocity ∼ 1000 km/s has been achieved under the operation of NIKE KrF laser at Naval Research Laboratory (laser wavelength=0.25μm) in the use of a planar target made of plastic and (2) We have performed two-dimensional simulation for burn and ignition to show the feasibility of the impact ignition. (author)

  15. Ignition tuning for the National Ignition Campaign

    OpenAIRE

    Landen O.; Edwards J.; Haan S.W.; Lindl J.D.; Boehly T.R.; Bradley D.K.; Callahan D.A.; Celliers P.M.; Dewald E.L.; Dixit S.; Doeppner T.; Eggert J.; Farley D.; Frenje J.A.; Glenn S.

    2013-01-01

    The overall goal of the indirect-drive inertial confinement fusion [1] tuning campaigns [2] is to maximize the probability of ignition by experimentally correcting for likely residual uncertainties in the implosion and hohlraum physics [3] used in our radiation-hydrodynamic computational models, and by checking for and resolving unexpected shot-to-shot variability in performance [4]. This has been started successfully using a variety of surrogate capsules that set key laser, hohlraum and caps...

  16. Myocarditis in auto-immune or auto-inflammatory diseases.

    Science.gov (United States)

    Comarmond, Cloé; Cacoub, Patrice

    2017-08-01

    Myocarditis is a major cause of heart disease in young patients and a common precursor of heart failure due to dilated cardiomyopathy. Some auto-immune and/or auto-inflammatory diseases may be accompanied by myocarditis, such as sarcoidosis, Behçet's disease, eosinophilic granulomatosis with polyangiitis, myositis, and systemic lupus erythematosus. However, data concerning myocarditis in such auto-immune and/or auto-inflammatory diseases are sparse. New therapeutic strategies should better target the modulation of the immune system, depending on the phase of the disease and the type of underlying auto-immune and/or auto-inflammatory disease. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. The volume ignition for ICF ignition target

    International Nuclear Information System (INIS)

    Li, Y. S.; He, X. T.; Yu, M.

    1997-01-01

    Compared with central model, volume ignition has no hot spot, avoids the mixing at the hot-cold interface, the α-particle escaping, and the high convergence, greatly reduces the sharp demanding for uniformity. In laser indirect driving, from theoretical estimation and computational simulation, we have proved that using a tamper with good heat resistance, the DT fuel can be ignited in LTE at ∼3 KeV and then evolves to the non-LTE ignition at >5 KeV. In this case, 1 MJ radiation energy in the hohlraum could cause near 10 MJ output for a pellet with 0.2 mg DT fuel. We have compared results with and without α-particle transport, it shows that in the condition of ρR>0.5 g/cm 2 of DT fuel, both have the same results. For the system with ρR≅0.5 g/cm 2 we can use α-particle local deposition scheme. The non-uniformly doped tamper with density ρ≅1-5 g/cc can reduce mixing due to the small convergence ratio. The input energy is deposited in DT and tamper during the implosion, we try to reduce the tamper energy by changing the ratio of CH and doped Au and the thickness of the tamper

  18. Probability of ignition - a better approach than ignition margin

    International Nuclear Information System (INIS)

    Ho, S.K.; Perkins, L.J.

    1989-01-01

    The use of a figure of merit - the probability of ignition - is proposed for the characterization of the ignition performance of projected ignition tokamaks. Monte Carlo and analytic models have been developed to compute the uncertainty distribution function for ignition of a given tokamak design, in terms of the uncertainties inherent in the tokamak physics database. A sample analysis with this method indicates that the risks of not achieving ignition may be unacceptably high unless the accepted margins for ignition are increased. (author). Letter-to-the-editor. 12 refs, 2 figs, 2 tabs

  19. AutoCAD / AutoCAD LT 2014 fundamentals metric

    CERN Document Server

    ASCENT center for technical knowledge

    2014-01-01

    The objective of AutoCAD/AutoCAD LT 2014 Fundamentals is to enable students to create a basic 2D drawing in the AutoCAD software. Even at this fundamental level, the AutoCAD software is one of the most sophisticated computer applications that you are likely to encounter. Therefore learning to use it can be challenging. To make the process easier and provide flexibility for instructors and students, the training guide is divided into two parts that can be taken independently.

  20. DNS with detailed and tabulated chemistry of engine relevant igniting systems

    NARCIS (Netherlands)

    Bekdemir, C.; Somers, L.M.T.; Goey, de L.P.H.

    2014-01-01

    Developments in modern engine technology are moving towards a regime with fuel injection uncoupled from combustion. Auto-ignition is an essential characteristic in these systems. The accurate prediction of this chemical process is of paramount importance. Tabulation techniques can provide a detailed

  1. Obtenção de concretos auto-escoantes zero-cimento a partir do controle reológico da matriz Production of self-flow zero-cement castables based on matrix rheological control

    Directory of Open Access Journals (Sweden)

    A. R. Studart

    2000-03-01

    Full Text Available Os concretos refratários auto-escoantes com reduzido teor de cimento têm se destacado pelo fato de associarem a facilidade de aplicação dos concretos de elevada fluidez, com o bom desempenho termomecânico dos refratários contendo baixo teor de CaO. Através do controle simultâneo da distribuição granulométrica e do estado de dispersão da matriz, é possível eliminar o cimento aluminoso (fonte de CaO e quaisquer outros ligantes hidráulicos do concreto, mantendo sua auto-escoabilidade. Os concretos obtidos, denominados zero-cimento, apresentam resistência mecânica a verde compatível com aplicações industriais e excelentes propriedades a altas temperaturas. Neste trabalho, são apresentadas as condições de dispersão da matriz necessárias para a obtenção dos concretos zero-cimento, após um ajuste granulométrico prévio. As faixas de pH e de teor de dispersante ideais para a otimização da reologia da matriz são apresentadas graficamente em um mapa de estabilidade, o qual mostrou-se uma ferramenta bastante útil para a formulação dos concretos auto-escoantes zero-cimento.Self-flow low-cement refractory castables have attracted much attention in the latest years because they combine the installation benefits of high-flowability castables with the good thermomechanical behaviour of low CaO-content refractories. By simultaneously controlling the castable particle size distribution and the matrix dispersion state, it becomes possible to eliminate the aluminous cement (CaO source or any other hydraulic binder in the castable, keeping its self-flow ability. Such castables, named self-flow zero-cement castables, exhibit pre-firing mechanical strength compatible with industrial applications and outstanding high temperature properties. The matrix dispersion conditions necessary to obtain these castables are presented in this work. The optimum range of pH and dispersant amount for the matrix rheological optimisation are

  2. Shot Automation for the National Ignition Facility

    International Nuclear Information System (INIS)

    Lagin, L J; Bettenhausen, R C; Beeler, R G; Bowers, G A; Carey, R.; Casavant, D.D.; Cline, B.D.; Demaret, R.D.; Domyancic, D.M.; Elko, S.D.; Fisher, J.M.; Hermann, M.R.; Krammen, J.E.; Kohut, T.R.; Marshall, C.D.; Mathisen, D.G.; Ludwigsen, A.P.; Patterson, Jr. R.W.; Sanchez, R.J.; Stout, E.A.; Van Arsdall, P.J.; Van Wonterghem, B.M.

    2005-01-01

    A shot automation framework has been developed and deployed during the past year to automate shots performed on the National Ignition Facility (NIF) using the Integrated Computer Control System This framework automates a 4-8 hour shot sequence, that includes inputting shot goals from a physics model, set up of the laser and diagnostics, automatic alignment of laser beams and verification of status. This sequence consists of set of preparatory verification shots, leading to amplified system shots using a 4-minute countdown, triggering during the last 2 seconds using a high-precision timing system, followed by post-shot analysis and archiving. The framework provides for a flexible, model-based execution driven of scriptable automation called macro steps. The framework is driven by high-level shot director software that provides a restricted set of shot life cycle state transitions to 25 collaboration supervisors that automate 8-laser beams (bundles) and a common set of shared resources. Each collaboration supervisor commands approximately 10 subsystem shot supervisors that perform automated control and status verification. Collaboration supervisors translate shot life cycle state commands from the shot director into sequences of ''macro steps'' to be distributed to each of its shot supervisors. Each Shot supervisor maintains order of macro steps for each subsystem and supports collaboration between macro steps. They also manage failure, restarts and rejoining into the shot cycle (if necessary) and manage auto/manual macro step execution and collaborations between other collaboration supervisors. Shot supervisors execute macro step shot functions commanded by collaboration supervisors. Each macro step has database-driven verification phases and a scripted perform phase. This provides for a highly flexible methodology for performing a variety of NIF shot types. Database tables define the order of work and dependencies (workflow) of macro steps to be performed for a

  3. Development of simulation technology on full auto air conditioning system; Auto eakon no simulation gijutsu no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, N; Otsubo, Y; Matsumura, K; Sako, H [Mazda Motor Corp., Hiroshima (Japan)

    1997-10-01

    Mazda has developed simulation technology on control of full auto air conditioning system. We have developed the development tool based on the technology, aiming at higher controllability of full auto air conditioning system and shorter development period. The tool performs simulation on control, on-vehicle evaluation of actual load operation, collecting data and analyzing them by personal computer. This paper reports our verification results on effectiveness of the technology/ and the tool. 4 refs., 9 figs.

  4. Physics aspects of the Compact Ignition Tokamak

    International Nuclear Information System (INIS)

    Post, D.; Bateman, G.; Houlberg, W.

    1986-11-01

    The Compact Ignition Tokamak (CIT) is a proposed modest-size ignition experiment designed to study the physics of alpha-particle heating. The basic concept is to achieve ignition in a modest-size minimum cost experiment by using a high plasma density to achieve the condition of ntau/sub E/ ∼ 2 x 10 20 sec m -3 required for ignition. The high density requires a high toroidal field (10 T). The high toroidal field allows a large plasma current (10 MA) which improves the energy confinement, and provides a high level of ohmic heating. The present CIT design also has a gigh degree of elongation (k ∼ 1.8) to aid in producing the large plasma current. A double null poloidal divertor and a pellet injector are part of the design to provide impurity and particle control, improve the confinement, and provide flexibility for impurity and particle control, improve the confinement, and provide flexibility for improving the plasma profiles. Since auxiliary heating is expected to be necessary to achieve ignition, 10 to 20 MW of Ion Cyclotron Radio Frequency (ICRF) is to be provided

  5. The mechanism of char ignition in fluidized bed combustors

    NARCIS (Netherlands)

    Siemons, R.V.

    1987-01-01

    Knowledge about ignition processes of coal in fluidized beds is of importance for the start-up and dynamic control of these combustors. Initial experiments in a transparent fluidized bed scale model showed the existence of a considerable induction period for the ignition of char, especially at low

  6. Laser ignited engines: progress, challenges and prospects.

    Science.gov (United States)

    Dearden, Geoff; Shenton, Tom

    2013-11-04

    Laser ignition (LI) has been shown to offer many potential benefits compared to spark ignition (SI) for improving the performance of internal combustion (IC) engines. This paper outlines progress made in recent research on laser ignited IC engines, discusses the potential advantages and control opportunities and considers the challenges faced and prospects for its future implementation. An experimental research effort has been underway at the University of Liverpool (UoL) to extend the stratified speed/load operating region of the gasoline direct injection (GDI) engine through LI research, for which an overview of some of the approaches, testing and results to date are presented. These indicate how LI can be used to improve control of the engine for: leaner operation, reductions in emissions, lower idle speed and improved combustion stability.

  7. An assessment of two off-shore igniter concepts

    International Nuclear Information System (INIS)

    Guenette, C. C.

    1997-01-01

    On June 12, 1996, two controlled in-situ oil spill burns (ISB), using a response-prepared ISB system, were conducted in the North Sea, 40 miles off the U. K. coast. The first burn involved fresh crude oil and was ignited with a hand-held igniter using a standard gelled fuel mixture. In the second burn an emulsified crude was used, ignited with a prototype emulsion breaking igniter (EBI) deployed using the Helitorch. The objective was to determine operational practicalities under realistic conditions when responding to a weathered oil situation in an offshore location. This paper is devoted to an assessment of the two igniter systems used during the trials. Results showed that oil aged by 12 hours with a 25 per cent water content burned down to a three-to-four per cent residue. The fire burn survived the two burns intact. The hand-held ignition system worked with fresh oil and the Helitorch lit emulsified oil using EBI. These trials were the first time that the EBI was deployed from a Helitorch slung beneath a helicopter. It was concluded that (1) the simplicity of the logistics required for the hand-held igniter would favour its use over the Helitorch method for fresh or lightly weathered oil, (2) more heavily weathered oils would require the use of an emulsion-breaking type igniter, and (3) aerial deployment of igniters offer the advantage of allowing more accurate positioning. 10 refs.,5 tabs., 3 figs

  8. Proton Fast Ignition

    International Nuclear Information System (INIS)

    Key, M H; Freeman, R R; Hatchett, S P; MacKinnon, A J; Patel, P K; Snavely, R A; Stephens, R B

    2006-04-01

    Fast ignition (FI) by a laser generated ballistically focused proton beam is a more recently proposed alternative to the original concept of FI by a laser generated beam of relativistic electrons. It has potential advantages in less complex energy transport into dense plasma. Recent successful target heating experiments motivate further investigation of the feasibility of proton fast ignition. The concept, the physics and characteristics of the proton beams, the recent experimental work on focusing of the beams and heating of solid targets and the overall prospects for proton FI are discussed

  9. Magnetically Assisted Fast Ignition

    OpenAIRE

    Wang, W.-M.; Gibbon, P.; Sheng, Z.-M.; Li, Y.-T.

    2015-01-01

    Fast ignition (FI) is investigated via integrated particle-in-cell simulation including both generation andtransport of fast electrons, where petawatt ignition lasers of 2 ps and compressed targets of a peak density of300 g cm−3 and areal density of 0.49 g cm−2 at the core are taken. When a 20 MG static magnetic field isimposed across a conventional cone-free target, the energy coupling from the laser to the core is enhancedby sevenfold and reaches 14%. This value even exceeds that obtained u...

  10. Characteristics of Early Flame Development in a Direct-Injection Spark-Ignition CNG Engine Fitted with a Variable Swirl Control Valve

    Directory of Open Access Journals (Sweden)

    Abd Rashid Abd Aziz

    2017-07-01

    Full Text Available An experimental study was conducted to investigate the effect of the structure of the induction flow on the characteristics of early flames in a lean-stratified and lean-homogeneous charge combustion of compressed natural gas (CNG fuel in a direct injection (DI engine at different engine speeds. The engine speed was varied at 1500 rpm, 1800 rpm and 2100 rpm, and the ignition timing was set at a 38.5° crank angle (CA after top dead center (TDC for all conditions. The engine was operated in a partial-load mode and a homogeneous air/fuel charge was achieved by injecting the fuel early (before the intake valve closure, while late injection during the compression stroke was used to produce a stratified charge. Different induction flow structures were obtained by adjusting the swirl control valves (SCV. Using an endoscopic intensified CCD (ICCD camera, flame images were captured and analyzed. Code was developed to analyze the level of distortion of the flame and its wrinkledness, displacement and position relative to the spark center, as well as the flame growth rate. The results showed a higher flame growth rate with the flame kernel in the homogeneous charge, compared to the stratified combustion case. In the stratified charge combustion scenario, the 10° SCV closure (medium-tumble resulted in a higher early flame growth rate, whereas a homogeneous charge combustion (characterized by strong swirl resulted in the highest rate of flame growth.

  11. Laser-ignited frontal polymerization of shape-controllable poly(VI-co-AM) hydrogels based on 3D templates toward adsorption of heavy metal ions

    Science.gov (United States)

    Fan, Suzhen; Liu, Sisi; Wang, Xiao-Qiao; Wang, Cai-Feng; Chen, Su

    2016-06-01

    Given the increasing heavy metal pollution issue, fast preparation of polymeric hydrogels with excellent adsorption property toward heavy metal ions is very attractive. In this work, a series of poly( N-vinylimidazole-co-acrylamide) (poly(VI-co-AM)) hydrogels were synthesized via laser-ignited frontal polymerization (LIFP) for the first time. The dependence of frontal velocity and temperature on two factors monomer ratios and initiator concentrations was systematically investigated. Poly(VI-co-AM) hydrogels with any self-supporting shapes can be synthesized by a one-step LIFP in seconds through the application of 3D templates. These shape-persistent hydrogels are pH-responsive and exhibit excellent adsorption/desorption characteristics toward Mn(II), Zn(II), Cd(II), Ni(II), Cu(II) and Co(II) ions, and the adsorption conformed to the pseudo-second-order kinetic model. The reusability of the hydrogels toward mental ions adsorption was further researched, which suggested that the hydrogels can be reused without serious decrease in adsorption capacity. This work might open a promising strategy to facilely prepare shape-controllable hydrogels and expand the application of LIFP.

  12. Auto-titrating continuous positive airway pressure treatment for obstructive sleep apnoea after acute quadriplegia (COSAQ): study protocol for a randomized controlled trial.

    Science.gov (United States)

    Berlowitz, David J; Ayas, Najib; Barnes, Maree; Brown, Douglas J; Cistulli, Peter A; Geraghty, Tim; Graham, Alison; Lee, Bonsan Bonne; Morris, Meg; O'Donoghue, Fergal; Rochford, Peter D; Ross, Jack; Singhal, Balraj; Spong, Jo; Wadsworth, Brooke; Pierce, Robert J

    2013-06-19

    Quadriplegia is a severe, catastrophic injury that predominantly affects people early in life, resulting in lifelong physical disability. Obstructive sleep apnoea is a direct consequence of quadriplegia and is associated with neurocognitive deficits, sleepiness and reduced quality of life. The usual treatment for sleep apnoea is nasal continuous positive airway pressure (CPAP); however, this is poorly tolerated in quadriplegia. To encourage patients to use this therapy, we have to demonstrate that the benefits outweigh the inconvenience. We therefore propose a prospective, multinational randomized controlled trial of three months of CPAP for obstructive sleep apnoea after acute quadriplegia. Specialist spinal cord injury centres across Australia, New Zealand, the UK and Canada will recruit medically stable individuals who have sustained a (new) traumatic quadriplegia (complete or incomplete second cervical to first thoracic level lesions). Participants will be screened for obstructive sleep apnoea using full, portable sleep studies. Those with an apnoea hypopnoea index greater than 10 per hour will proceed to an initial three-night trial of CPAP. Those who can tolerate CPAP for at least 4 hours on at least one night of the initial trial will be randomized to either usual care or a 3-month period of auto-titrating CPAP. The primary hypothesis is that nocturnal CPAP will improve neuropsychological functioning more than usual care alone. The secondary hypothesis is that the magnitude of improvement of neuropsychological function will be predicted by the severity of baseline sleepiness measures, sleep fragmentation and sleep apnoea. Neuropsychological tests and full polysomnography will be performed at baseline and 3 months with interim measures of sleepiness and symptoms of autonomic dysfunction measured weekly. Spirometry will be performed monthly. Neuropsychological tests will be administered by blinded assessors. Recruitment commenced in July 2009. The results of

  13. Multimodal Friction Ignition Tester

    Science.gov (United States)

    Davis, Eddie; Howard, Bill; Herald, Stephen

    2009-01-01

    The multimodal friction ignition tester (MFIT) is a testbed for experiments on the thermal and mechanical effects of friction on material specimens in pressurized, oxygen-rich atmospheres. In simplest terms, a test involves recording sensory data while rubbing two specimens against each other at a controlled normal force, with either a random stroke or a sinusoidal stroke having controlled amplitude and frequency. The term multimodal in the full name of the apparatus refers to a capability for imposing any combination of widely ranging values of the atmospheric pressure, atmospheric oxygen content, stroke length, stroke frequency, and normal force. The MFIT was designed especially for studying the tendency toward heating and combustion of nonmetallic composite materials and the fretting of metals subjected to dynamic (vibrational) friction forces in the presence of liquid oxygen or pressurized gaseous oxygen test conditions approximating conditions expected to be encountered in proposed composite material oxygen tanks aboard aircraft and spacecraft in flight. The MFIT includes a stainless-steel pressure vessel capable of retaining the required test atmosphere. Mounted atop the vessel is a pneumatic cylinder containing a piston for exerting the specified normal force between the two specimens. Through a shaft seal, the piston shaft extends downward into the vessel. One of the specimens is mounted on a block, denoted the pressure block, at the lower end of the piston shaft. This specimen is pressed down against the other specimen, which is mounted in a recess in another block, denoted the slip block, that can be moved horizontally but not vertically. The slip block is driven in reciprocating horizontal motion by an electrodynamic vibration exciter outside the pressure vessel. The armature of the electrodynamic exciter is connected to the slip block via a horizontal shaft that extends into the pressure vessel via a second shaft seal. The reciprocating horizontal

  14. Auto-fotografi som metode

    DEFF Research Database (Denmark)

    Mogensen, Mette

    2014-01-01

    Artiklen sætter fokus på auto-fotografi som metode i arbejdsmiljøforskningen. Den organisationsæstetiske tilgang, som metoden ofte forbindes med, udfordres med afsæt i en performativ og aktørnetværks-teoretisk position. Gennem en analyse af et enkelt auto-fotografi vises hvordan en artikulation af...

  15. Progress towards ignition on the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, M. J.; Patel, P. K.; Lindl, J. D.; Atherton, L. J.; Glenzer, S. H.; Haan, S. W.; Landen, O. L.; Moses, E. I.; Springer, P. T.; Benedetti, R.; Bernstein, L.; Bleuel, D. L.; Bradley, D. K.; Caggiano, J. A.; Callahan, D. A.; Celliers, P. M.; Cerjan, C. J.; Clark, D. S.; Collins, G. W.; Dewald, E. L. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States); and others

    2013-07-15

    The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory includes a precision laser system now capable of delivering 1.8 MJ at 500 TW of 0.35-μm light to a target. NIF has been operational since March 2009. A variety of experiments have been completed in support of NIF's mission areas: national security, fundamental science, and inertial fusion energy. NIF capabilities and infrastructure are in place to support its missions with nearly 60 X-ray, optical, and nuclear diagnostic systems. A primary goal of the National Ignition Campaign (NIC) on the NIF was to implode a low-Z capsule filled with ∼0.2 mg of deuterium-tritium (DT) fuel via laser indirect-drive inertial confinement fusion and demonstrate fusion ignition and propagating thermonuclear burn with a net energy gain of ∼5–10 (fusion yield/input laser energy). This requires assembling the DT fuel into a dense shell of ∼1000 g/cm{sup 3} with an areal density (ρR) of ∼1.5 g/cm{sup 2}, surrounding a lower density hot spot with a temperature of ∼10 keV and a ρR ∼0.3 g/cm{sup 2}, or approximately an α-particle range. Achieving these conditions demand precise control of laser and target parameters to allow a low adiabat, high convergence implosion with low ablator fuel mix. We have demonstrated implosion and compressed fuel conditions at ∼80–90% for most point design values independently, but not at the same time. The nuclear yield is a factor of ∼3–10× below the simulated values and a similar factor below the alpha dominated regime. This paper will discuss the experimental trends, the possible causes of the degraded performance (the off-set from the simulations), and the plan to understand and resolve the underlying physics issues.

  16. Ignition experiment - alternatives

    International Nuclear Information System (INIS)

    Knobloch, A.F.

    1979-10-01

    This report comprises three short papers on cost estimates, integral burn time and alternative versions of Tokamak ignition experiments. These papers were discussed at the ZEPHYR workshop with participants from IPP Garching, MIT Cambridge and PPPL Princeton (Garching July 30 - August 2 1979) (Chapters A, B, C). It is shown, that starting from a practical parameter independent minimum integral burn time of Tokamak ignition experiments (some 10 3 s) by adding a shield for protection of the magnet insulation (permitted neutron dose 10 9 rad) an integral burn time of some 10 4 s can be achieved for only about 30% more outlay. For a substantially longer integral burn time the outlay approaches rather quickly that for a Tokamak reactor. Some examples for alternatives to ZEPHYR are being given, including some with low or no compression. In a further chapter D some early results of evaluating an ignition experiment on the basis of the energy confinement scaling put forward by Coppi and Mazzucato are presented. As opposed to the case of the Alcator scaling used in chapters A through C the minimum integral burn time of Tokamak ignition experiments here depends on the plasma current. Provided neutral injectors up to about 160 keV are available compression boosting is not required with this scaling. The results presented have been obtained neglecting the effects of the toroidal field ripple. (orig.) 891 HT/orig. 892 RKD [de

  17. Variable valve timing in a homogenous charge compression ignition engine

    Science.gov (United States)

    Lawrence, Keith E.; Faletti, James J.; Funke, Steven J.; Maloney, Ronald P.

    2004-08-03

    The present invention relates generally to the field of homogenous charge compression ignition engines, in which fuel is injected when the cylinder piston is relatively close to the bottom dead center position for its compression stroke. The fuel mixes with air in the cylinder during the compression stroke to create a relatively lean homogeneous mixture that preferably ignites when the piston is relatively close to the top dead center position. However, if the ignition event occurs either earlier or later than desired, lowered performance, engine misfire, or even engine damage, can result. The present invention utilizes internal exhaust gas recirculation and/or compression ratio control to control the timing of ignition events and combustion duration in homogeneous charge compression ignition engines. Thus, at least one electro-hydraulic assist actuator is provided that is capable of mechanically engaging at least one cam actuated intake and/or exhaust valve.

  18. Present status of Fast Ignition Realization EXperiment (FIREX) and inertial fusion energy development

    International Nuclear Information System (INIS)

    Azechi, H.; Fujimoto, Y.; Fujioka, S.

    2012-11-01

    Controlled thermonuclear ignition and subsequent burn will be demonstrated in a couple of years on the central ignition scheme. Fast ignition has the high potential to ignite a fuel using only about one tenth of laser energy necessary to the central ignition. This compactness may largely accelerate inertial fusion energy development. One of the most advanced fast ignition programs is the Fast Ignition Realization Experiment (FIREX). The goal of its first phase is to demonstrate ignition temperature of 5 keV, followed by the second phase to demonstrate ignition-and-burn. The second series experiment of FIREX-I from late 2010 to early 2011 has demonstrated a high (≈20%) coupling efficiency from laser to thermal energy of the compressed core, suggesting that one can achieve the ignition temperature at the laser energy below 10 kJ. Given the demonstrations of the ignition temperature at FIREX-I and the ignition-and-burn at the National Ignition Facility, the inertial fusion research would then shift from the plasma physics era to power generation era. (author)

  19. Spark ignition engine control: estimation and prediction of the in-cylinder mass and chemical species; Controle moteur a allumage commande: estimation / prediction de la masse et de la composition du melange enferme dans le cylindre

    Energy Technology Data Exchange (ETDEWEB)

    Giansetti, P.

    2005-09-15

    Spark ignition engine control has become a major issue regarding compliance with emissions legislation while ensuring driving comfort. The objective of this thesis was to estimate the mass and composition of gases inside the cylinder of an engine based on physics in order to insure better control of transient phases taking into account residual gases as well as exhaust gas recirculation. Residual gas fraction has been characterized using two experiments and one CFD code. A model has been validated experimentally and integrated into an observer which predicts pressure and temperature inside the manifold. The predictions of the different gas flows and the chemical species inside the cylinder are deduced. A closed loop observer has been validated experimentally and in simulation. Moreover, an algorithm estimating the fresh and burned gas mass from the cylinder pressure has been proposed in order to obtain the information cycle by cycle and cylinder by cylinder. (author)

  20. Equilibrium ignition for ICF capsules

    International Nuclear Information System (INIS)

    Lackner, K.S.; Colgate, S.A.; Johnson, N.L.; Kirkpatrick, R.C.; Menikoff, R.; Petschek, A.G.

    1993-01-01

    There are two fundamentally different approaches to igniting DT fuel in an ICF capsule which can be described as equilibrium and hot spot ignition. In both cases, a capsule which can be thought of as a pusher containing the DT fuel is imploded until the fuel reaches ignition conditions. In comparing high-gain ICF targets using cryogenic DT for a pusher with equilibrium ignition targets using high-Z pushers which contain the radiation. The authors point to the intrinsic advantages of the latter. Equilibrium or volume ignition sacrifices high gain for lower losses, lower ignition temperature, lower implosion velocity and lower sensitivity of the more robust capsule to small fluctuations and asymmetries in the drive system. The reduction in gain is about a factor of 2.5, which is small enough to make the more robust equilibrium ignition an attractive alternative

  1. AutoCAD 2014 essentials

    CERN Document Server

    Onstott, Scott

    2013-01-01

    Learn crucial AutoCAD tools and techniques with this Autodesk Official Press Book Quickly become productive using AutoCAD 2014 and AutoCAD LT 2014 with this full color Autodesk Official Press guide. This unique learning resource features concise, straightforward explanations and real-world, hands-on exercises and tutorials. Following a quick discussion of concepts and goals, each chapter moves on to an approachable hands-on exercise designed to reinforce real-world tactics and techniques. Compelling, full-color screenshots illustrate tutorial steps, and chapters conclude with relat

  2. Numerical Investigation of a Gasoline-Like Fuel in a Heavy-Duty Compression Ignition Engine Using Global Sensitivity Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Pinaki; Probst, Daniel; Pei, Yuanjiang; Zhang, Yu; Traver, Michael; Cleary, David; Som, Sibendu

    2017-03-28

    Fuels in the gasoline auto-ignition range (Research Octane Number (RON) > 60) have been demonstrated to be effective alternatives to diesel fuel in compression ignition engines. Such fuels allow more time for mixing with oxygen before combustion starts, owing to longer ignition delay. Moreover, by controlling fuel injection timing, it can be ensured that the in-cylinder mixture is “premixed enough” before combustion occurs to prevent soot formation while remaining “sufficiently inhomogeneous” in order to avoid excessive heat release rates. Gasoline compression ignition (GCI) has the potential to offer diesel-like efficiency at a lower cost and can be achieved with fuels such as low-octane straight run gasoline which require significantly less processing in the refinery compared to today’s fuels. To aid the design and optimization of a compression ignition (CI) combustion system using such fuels, a global sensitivity analysis (GSA) was conducted to understand the relative influence of various design parameters on efficiency, emissions and heat release rate. The design parameters included injection strategies, exhaust gas recirculation (EGR) fraction, temperature and pressure at intake valve closure and injector configuration. These were varied simultaneously to achieve various targets of ignition timing, combustion phasing, overall burn duration, emissions, fuel consumption, peak cylinder pressure and maximum pressure rise rate. The baseline case was a three-dimensional closed-cycle computational fluid dynamics (CFD) simulation with a sector mesh at medium load conditions. Eleven design parameters were considered and ranges of variation were prescribed to each of these. These input variables were perturbed in their respective ranges using the Monte Carlo (MC) method to generate a set of 256 CFD simulations and the targets were calculated from the simulation results. GSA was then applied as a screening tool to identify the input parameters having the most

  3. Investigating the reactivity controlled compression ignition (RCCI) combustion strategy in a natural gas/diesel fueled engine with a pre-chamber

    International Nuclear Information System (INIS)

    Salahi, Mohammad Mahdi; Esfahanian, Vahid; Gharehghani, Ayatallah; Mirsalim, Mostafa

    2017-01-01

    Highlights: • A novel combustion strategy, RCCI with a pre-chamber, is proposed and investigated. • The proposed strategy extends the RCCI operating range to use less intake air temperatures. • The new concept extends the RCCI operating range to use lower portions of the active fuel. • The proposed strategy is sensitive to engine load and is more efficient for high loads. - Abstract: Reactivity controlled compression ignition (RCCI) concept has been proven to be a promising combustion mode for the next generations of internal combustion engines. This strategy is still subject of extensive studies to overcome its operational limitations. In the present work, the effect of using a pre-chamber to extend some operating ranges in a RCCI engine is investigated using coupled multidimensional computational fluid dynamics (CFD) with detailed chemical kinetic mechanisms. To accomplish this, the combustion and flow field in a single cylinder engine with a pre-chamber, working in RCCI mode and fueled with natural gas/diesel are numerically modeled. Experimental data is used to validate the simulation results and then, combustion characteristics and engine emissions in some various operating regions, in terms of initial temperature, fuel equivalence ratio and portions of the two fuels are discussed. The results reveal that the proposed strategy provides the ability to extend the engine operating ranges to use lower intake temperatures, even to 50 K lower for some cases, and also using a larger portion of natural gas instead of diesel fuel. On the other hand, the new strategy could result in incomplete combustion and formation of related emissions in low loads, but for higher engine loads it shows better combustion characteristics.

  4. [Design of blood-pressure parameter auto-acquisition circuit].

    Science.gov (United States)

    Chen, Y P; Zhang, D L; Bai, H W; Zhang, D A

    2000-02-01

    This paper presents the realization and design of a kind of blood-pressure parameter auto-acquisition circuit. The auto-acquisition of blood-pressure parameter controlled by 89C2051 single chip microcomputer is accomplished by collecting and processing the driving signal of LCD. The circuit that is successfully applied in the home unit of telemedicine system has the simple and reliable properties.

  5. Knock Prediction Using a Simple Model for Ignition Delay

    KAUST Repository

    Kalghatgi, Gautam

    2016-04-05

    An earlier paper has shown the ability to predict the phasing of knock onset in a gasoline PFI engine using a simple ignition delay equation for an appropriate surrogate fuel made up of toluene and PRF (TPRF). The applicability of this approach is confirmed in this paper in a different engine using five different fuels of differing RON, sensitivity, and composition - including ethanol blends. An Arrhenius type equation with a pressure correction for ignition delay can be found from interpolation of previously published data for any gasoline if its RON and sensitivity are known. Then, if the pressure and temperature in the unburned gas can be estimated or measured, the Livengood-Wu integral can be estimated as a function of crank angle to predict the occurrence of knock. Experiments in a single cylinder DISI engine over a wide operating range confirm that this simple approach can predict knock very accurately. The data presented should enable engineers to study knock or other auto-ignition phenomena e.g. in premixed compression ignition (PCI) engines without explicit chemical kinetic calculations. © Copyright 2016 SAE International.

  6. Esma Auto ja Mazda on loodud kestma

    Index Scriptorium Estoniae

    2003-01-01

    Ülevaade olulisematest sündmustest Esma Auto kümne tegevusaasta jooksul. Kommenteerivad Tarmo Järvoja, Mart Laar ja Enn Sau. Diagrammid ja skeemid: AS Esma Auto müügi statistika läbi aastate; AS Esma Auto kasum ja klientide arv aastate lõikes; Esma Auto esindused Eestis ja pakutavad teenused

  7. Shock Tube Ignition Delay Data Affected by Localized Ignition Phenomena

    KAUST Repository

    Javed, Tamour

    2016-12-29

    Shock tubes have conventionally been used for measuring high-temperature ignition delay times ~ O(1 ms). In the last decade or so, the operating regime of shock tubes has been extended to lower temperatures by accessing longer observation times. Such measurements may potentially be affected by some non-ideal phenomena. The purpose of this work is to measure long ignition delay times for fuels exhibiting negative temperature coefficient (NTC) and to assess the impact of shock tube non-idealities on ignition delay data. Ignition delay times of n-heptane and n-hexane were measured over the temperature range of 650 – 1250 K and pressures near 1.5 atm. Driver gas tailoring and long length of shock tube driver section were utilized to measure ignition delay times as long as 32 ms. Measured ignition delay times agree with chemical kinetic models at high (> 1100 K) and low (< 700 K) temperatures. In the intermediate temperature range (700 – 1100 K), however, significant discrepancies are observed between the measurements and homogeneous ignition delay simulations. It is postulated, based on experimental observations, that localized ignition kernels could affect the ignition delay times at the intermediate temperatures, which lead to compression (and heating) of the bulk gas and result in expediting the overall ignition event. The postulate is validated through simple representative computational fluid dynamic simulations of post-shock gas mixtures which exhibit ignition advancement via a hot spot. The results of the current work show that ignition delay times measured by shock tubes may be affected by non-ideal phenomena for certain conditions of temperature, pressure and fuel reactivity. Care must, therefore, be exercised in using such data for chemical kinetic model development and validation.

  8. Pulse heating and ignition for off-centre ignited targets

    International Nuclear Information System (INIS)

    Mahdy, A.I.; Takabe, H.; Mima, K.

    1999-01-01

    An off-centre ignition model has been used to study the ignition conditions for laser targets related to the fast ignition scheme. A 2-D hydrodynamic code has been used, including alpha particle heating. The main goal of the study is the possibility of obtaining a high gain ICF target with fast ignition. In order to determine the ignition conditions, samples with various compressed core densities having different spark density-radius product (i.e. areal density) values were selected. The study was carried out in the presence of an external heating source, with a constant heating rate. A dependence of the ignition conditions on the heating rate of the external pulse is demonstrated. For a given set of ignition conditions, our simulation showed that an 11 ps pulse with 17 kJ of injected energy into the spark area was required to achieve ignition for a compressed core with a density of 200 g/cm 3 and 0.5 g/cm 2 spark areal density. It is shown that the ignition conditions are highly dependent on the heating rate of the external pulse. (author)

  9. Ignition and fusion burn in fast ignition scheme

    International Nuclear Information System (INIS)

    Takabe, Hideaki

    1998-01-01

    The target physics of fast ignition is briefly reviewed by focusing on the ignition and fusion burn in the off-center ignition scheme. By the use of a two dimensional hydrodynamic code with an alpha heating process, the ignition condition is studied. It is shown that the ignition condition of the off-center ignition scheme coincides with that of the the central isochoric model. After the ignition, a nuclear burning wave is seen to burn the cold main fuel with a velocity of 2 - 3 x 10 8 cm/s. The spark energy required for the off-center ignition is 2 - 3 kJ or 10 - 15 kJ for the core density of 400 g/cm 3 or 200 g/cm 3 , respectively. It is demonstrated that a core gain of more than 2,000 is possible for a core energy of 100 kJ with a hot spark energy of 13 kJ. The requirement for the ignition region's heating time is also discussed by modeling a heating source in the 2-D code. (author)

  10. Propellant Flow Actuated Piezoelectric Rocket Engine Igniter, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Spark ignition of a bi-propellant rocket engine is a classic, proven, and generally reliable process. However, timing can be critical, and the control logic,...

  11. Central ignition scenarios for TFTR

    International Nuclear Information System (INIS)

    Zweben, S.J.; Redi, M.H.; Bateman, G.

    1986-03-01

    The possibility of obtaining ignition in TFTR by means of very centrally peaked density profiles is examined. It is shown that local central alpha heating can be made to exceed local central energy losses (''central ignition'') under global conditions for which Q greater than or equal to 1. Time dependent 1-D transport simulations show that the normal global ignition requirements are substantially relaxed for plasmas with peaked density profiles. 18 refs., 18 figs

  12. Safety Implementation of Hydrogen Igniters and Recombiners for Nuclear Power Plant Severe Accident Management

    Institute of Scientific and Technical Information of China (English)

    XIAO Jianjun; ZHOU Zhiwei; JING Xingqing

    2006-01-01

    Hydrogen combustion in a nuclear power plant containment building may threaten the integrity of the containment. Hydrogen recombiners and igniters are two methods to reduce hydrogen levels in containment buildings during severe accidents. The purpose of this paper is to evaluate the safety implementation of hydrogen igniters and recombiners. This paper analyzes the risk of deliberate hydrogen ignition and investigates three mitigation measures using igniters only, hydrogen recombiners only or a combination of recombiners and igniters. The results indicate that steam can effectively control the hydrogen flame acceleration and the deflagration-to-detonation transition.

  13. Auto-adaptative Robot-aided Therapy based in 3D Virtual Tasks controlled by a Supervised and Dynamic Neuro-Fuzzy System

    Directory of Open Access Journals (Sweden)

    Luis Daniel Lledó

    2015-03-01

    Full Text Available This paper presents an application formed by a classification method based on the architecture of ART neural network (Adaptive Resonance Theory and the Fuzzy Set Theory to classify physiological reactions in order to automatically and dynamically adapt a robot-assisted rehabilitation therapy to the patient needs, using a three-dimensional task in a virtual reality system. Firstly, the mathematical and structural model of the neuro-fuzzy classification method is described together with the signal and training data acquisition. Then, the virtual designed task with physics behavior and its development procedure are explained. Finally, the general architecture of the experimentation for the auto-adaptive therapy is presented using the classification method with the virtual reality exercise.

  14. Assessment of Factors Related to Auto-PEEP.

    Science.gov (United States)

    Natalini, Giuseppe; Tuzzo, Daniele; Rosano, Antonio; Testa, Marco; Grazioli, Michele; Pennestrì, Vincenzo; Amodeo, Guido; Marsilia, Paolo F; Tinnirello, Andrea; Berruto, Francesco; Fiorillo, Marialinda; Filippini, Matteo; Peratoner, Alberto; Minelli, Cosetta; Bernardini, Achille

    2016-02-01

    Previous physiological studies have identified factors that are involved in auto-PEEP generation. In our study, we examined how much auto-PEEP is generated from factors that are involved in its development. One hundred eighty-six subjects undergoing controlled mechanical ventilation with persistent expiratory flow at the beginning of each inspiration were enrolled in the study. Volume-controlled continuous mandatory ventilation with PEEP of 0 cm H2O was applied while maintaining the ventilator setting as chosen by the attending physician. End-expiratory and end-inspiratory airway occlusion maneuvers were performed to calculate respiratory mechanics, and tidal flow limitation was assessed by a maneuver of manual compression of the abdomen. The variable with the strongest effect on auto-PEEP was flow limitation, which was associated with an increase of 2.4 cm H2O in auto-PEEP values. Moreover, auto-PEEP values were directly related to resistance of the respiratory system and body mass index and inversely related to expiratory time/time constant. Variables that were associated with the breathing pattern (tidal volume, frequency minute ventilation, and expiratory time) did not show any relationship with auto-PEEP values. The risk of auto-PEEP ≥5 cm H2O was increased by flow limitation (adjusted odds ratio 17; 95% CI: 6-56.2), expiratory time/time constant ratio 15 cm H2O/L s (3; 1.3-6.9), age >65 y (2.8; 1.2-6.5), and body mass index >26 kg/m(2) (2.6; 1.1-6.1). Flow limitation, expiratory time/time constant, resistance of the respiratory system, and obesity are the most important variables that affect auto-PEEP values. Frequency expiratory time, tidal volume, and minute ventilation were not independently associated with auto-PEEP. Therapeutic strategies aimed at reducing auto-PEEP and its adverse effects should be primarily oriented to the variables that mainly affect auto-PEEP values. Copyright © 2016 by Daedalus Enterprises.

  15. High-Gain Shock Ignition on the National Ignition Facility

    Science.gov (United States)

    Perkins, L. J.; Lafortune, K.; Bailey, D.; Lambert, M.; MacKinnon, A.; Blackfield, D.; Comley, A.; Schurtz, G.; Ribeyre, X.; Lebel, E.; Casner, A.; Craxton, R. S.; Betti, R.; McKenty, P.; Anderson, K.; Theobald, W.; Schmitt, A.; Atzeni, S.; Schiavi, A.

    2010-11-01

    Shock ignition offers the possibility for a near-term test of high-gain ICF on the NIF at less than 1MJ drive energy and with day-1 laser hardware. We will summarize the status of target performance simulations, delineate the critical issues and describe the R&D program to be performed in order to test the potential of a shock-ignited target on NIF. In shock ignition, compressed fuel is separately ignited by a late-time laser-driven shock and, because capsule implosion velocities are significantly lower than those required for conventional hotpot ignition, simulations indicate that fusion energy gains of 60 may be achievable at laser energies around 0.5MJ. Like fast ignition, shock ignition offers high gain but requires only a single laser with less demanding timing and focusing requirements. Conventional symmetry and stability constraints apply, thus a key immediate step towards attempting shock ignition on NIF is to demonstrate adequacy of low-mode uniformity and shock symmetry under polar drive

  16. Compact ignition experiments

    International Nuclear Information System (INIS)

    Angelini, A.; Coppi, B.; Nassi, M.

    1992-01-01

    This paper reports on high magnetic field experiments which can be designed to investigate D-T ignition conditions based on present-day experimental results and theoretical understanding of plasma phenomena. The key machine elements are: large plasma currents, compact dimensions, tight aspect ratios, moderate elongations and significant triangularities of the plasma column. High plasma densities, strong ohmic heating, the needed degree of energy confinement, good plasma purity and robust stability against ideal and resistive instabilities can be achieved simultaneously. The Ignitor design incorporates all these characteristics and involves magnet technology developments, started with the Alcator experiment, that use cryogenically cooled normal conductors

  17. AutoCAD 2015 and AutoCAD LT 2015

    CERN Document Server

    Gladfelter, Donnie

    2014-01-01

    Learn AutoCAD by example with this tutorial-based guide from Autodesk Official Press Whether you are just starting out or an experienced user wanting to brush up on your skills, this Autodesk Official Press book provides you with concise explanations, focused examples, and step-by-step instructions through a hands-on tutorial project that runs throughout the book. As you progress through the project, the book introduces you to the Microsoft Windows-based AutoCAD interface and then guides you through basic commands and creating drawings. A downloadable file is available from the website so that

  18. Ignition and Inertial Confinement Fusion at The National Ignition Facility

    International Nuclear Information System (INIS)

    Moses, E.

    2009-01-01

    The National Ignition Facility (NIF), the world's largest and most powerful laser system for inertial confinement fusion (ICF) and for studying high-energy-density (HED) science, is now operational at Lawrence Livermore National Laboratory (LLNL). The NIF is now conducting experiments to commission the laser drive, the hohlraum and the capsule and to develop the infrastructure needed to begin the first ignition experiments in FY 2010. Demonstration of ignition and thermonuclear burn in the laboratory is a major NIF goal. NIF will achieve this by concentrating the energy from the 192 beams into a mm 3 -sized target and igniting a deuterium-tritium mix, liberating more energy than is required to initiate the fusion reaction. NIF's ignition program is a national effort managed via the National Ignition Campaign (NIC). The NIC has two major goals: execution of DT ignition experiments starting in FY2010 with the goal of demonstrating ignition and a reliable, repeatable ignition platform by the conclusion of the NIC at the end of FY2012. The NIC will also develop the infrastructure and the processes required to operate NIF as a national user facility. The achievement of ignition at NIF will demonstrate the scientific feasibility of ICF and focus worldwide attention on laser fusion as a viable energy option. A laser fusion-based energy concept that builds on NIF, known as LIFE (Laser Inertial Fusion Energy), is currently under development. LIFE is inherently safe and can provide a global carbon-free energy generation solution in the 21st century. This paper describes recent progress on NIF, NIC, and the LIFE concept.

  19. Tokamak and RFP ignition requirements

    International Nuclear Information System (INIS)

    Werley, K.A.

    1991-01-01

    A plasma model is applied to calculate numerically transport- confinement (nτ E ) requirements and steady-state operation tokamak. The CIT tokamak and RFP ignition conditions are examined. Physics differences between RFP and tokamaks, and their consequences for a DT ignition machine, are discussed. The ignition RFP, compared to a tokamak, has many physics advantages, including ohmic heating to ignition (no need for auxiliary heating systems), higher beta, low ignition current, less sensitivity of ignition requirements to impurity effects, no hard disruptions (associated with beta or density limits), and successful operation with high radiation fractions (f RAD ∼ 0.95). These physics advantages, coupled with important engineering advantages associated with lower external magnetic fields, larger aspect ratios, and smaller plasma cross sections translate into significant cost reductions for both ignition and power reactor. The primary drawback of the RFP is the uncertainty that the present confinement scaling will extrapolate to reactor regimes. The 4-MA ZTH was expected to extend the nτ E transport scaling data three order of magnitude above ZT-40M results, and if the present scaling held, to achieve a DT-equivalent scientific energy breakeven, Q=1. A basecase RFP ignition point is identified with a plasma current of 8.1 MA and no auxiliary heating. 16 refs., 4 figs., 1 tab

  20. AutoCAD 2010 For Dummies

    CERN Document Server

    Byrnes, David

    2009-01-01

    AutoCAD is the hot computer-aided design software known for both its powerful tools and its complexity. AutoCAD 2010 for Dummies is the bestselling guide that walks you through this complicated program so you can build complex 3D technical drawings, edit like a pro, enter new dimensions, and plot with style. AutoCAD 2010 for Dummies helps you navigate the program, use the AutoCAD Design Center, create a basic layout and work with dimension, and put your drawings on the Internet. You'll soon be setting up the AutoCAD environment, using the AutoCAD Ribbon, creating annotation and dimension drawi

  1. Time-dependent simulations of a Compact Ignition Tokamak

    International Nuclear Information System (INIS)

    Stotler, D.P.; Bateman, G.

    1988-05-01

    Detailed simulations of the Compact Ignition Tokamak are carried out using a 1-1/2-D transport code. The calculations include time-varying densities, fields, and plasma shape. It is shown that ignition can be achieved in this device if somewhat better than L-mode energy confinement time scaling is possible. We also conclude that the performance of such a compact, short-pulse device can depend greatly on how the plasma is evolved to its flat-top parameters. Furthermore, in cases such as the ones discussed here, where there is not a great deal of ignition margin and the electron density is held constant, ignition ends if the helium ash is not removed. In general, control of the deuterium--tritium density is equivalent to burn control. 48 refs., 15 figs

  2. Self-ignition of explosive substance. Comparison between analytical and numerical calculations in order to optimize safety in a pyrotechnic context; Auto-inflammation de substances explosives. Comparaison entre calcul analytique et numerique en vue d`une optimisation dans le domaine de la pyrotechnie

    Energy Technology Data Exchange (ETDEWEB)

    Gillard, Ph. [Centre National de la Recherche Scientifique (CNRS), 86 - Poitiers (France)

    1998-04-01

    Self-ignition of energetic material was investigated in order to optimize safety in the field of pyrotechnic applications. Two approaches were used; the first one is relative to Frank-Kamenetskii stationary thermal explosion theory. The second approach consists of a choice of some numerical solutions of heat conduction equations in a non-stationary state. Comparison between these results was carried out in order to find the numerical scheme which is the most compatible with Frank-Kamenetskii stationary thermal explosion theory. Numerical data were used for three explosive substances. One of them was studied by the author. In all cases, the numerical stationary state is in agreement with the Frank-Kamenetskii stationary thermal explosion theory, more or less accurately. From this comparison, it may be concluded that it is preferable, for this kind of problem, to use an implicit scheme with linearization of the heat source term. Explicit numerical methods, with or without the addition of the heat term with the Zinn and Mader scheme are revealed to be less accurate and to need a greater optimization of spatial and temporal meshing. (author) 7 refs.

  3. Target design for shock ignition

    International Nuclear Information System (INIS)

    Schurtz, G; Ribeyre, X; Lafon, M

    2010-01-01

    The conventional approach of laser driven inertial fusion involves the implosion of cryogenic shells of deuterium-tritium ice. At sufficiently high implosion velocities, the fuel ignites by itself from a central hot spot. In order to reduce the risks of hydrodynamic instabilities inherent to large implosion velocities, it was proposed to compress the fuel at low velocity, and ignite the compressed fuel by means of a convergent shock wave driven by an intense spike at the end of the laser pulse. This scheme, known as shock ignition, reduces the risks of shell break-up during the acceleration phase, but it may be impeded by a low coupling efficiency of the laser pulse with plasma at high intensities. This work provides a relationship between the implosion velocity and the laser intensity required to ignite the target by a shock. The operating domain of shock ignition at different energies is described.

  4. Ignition technique for an in situ oil shale retort

    Science.gov (United States)

    Cha, Chang Y.

    1983-01-01

    A generally flat combustion zone is formed across the entire horizontal cross-section of a fragmented permeable mass of formation particles formed in an in situ oil shale retort. The flat combustion zone is formed by either sequentially igniting regions of the surface of the fragmented permeable mass at successively lower elevations or by igniting the entire surface of the fragmented permeable mass and controlling the rate of advance of various portions of the combustion zone.

  5. Ignition system for an internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Imhof, G

    1977-05-12

    The invention pertains to ignition systems for internal combustion engines; in particular, these are used in the engines of modern small motorcycles, where power is supplied by means of a so-called flywheel magneto, so that there is no need for an additional battery. The invention will prevent back-kicking. This is achieved by the following means: in the right direction of rotation of the internal combustion engine, due to an axial magnetic unsymmetry of the rotor, a voltage component that can switch the electronic switch will occur only in one of the two parts of the control winding at the point of ignition. In the wrong direction of rotation, on the other hand, this voltage component will only occur in the other part of the control winding and will act in direction on a diode connected in parallel to this part of the winding.

  6. The Ignition Target for the National Ignition Facility

    International Nuclear Information System (INIS)

    Atherton, L J; Moses, E I; Carlisle, K; Kilkenny, J

    2007-01-01

    The National Ignition Facility (NIF) is a 192 beam Nd-glass laser facility presently under construction at Lawrence Livermore National Laboratory (LLNL) for performing inertial confinement fusion (ICF) and experiments studying high energy density (HED) science. When completed in 2009, NIF will be able to produce 1.8 MJ, 500 TW of ultraviolet light for target experiments that will create conditions of extreme temperatures (>10 8 K), pressures (10-GBar) and matter densities (> 100 g/cm 3 ). A detailed program called the National Ignition Campaign (NIC) has been developed to enable ignition experiments in 2010, with the goal of producing fusion ignition and burn of a deuterium-tritium (DT) fuel mixture in millimeter-scale target capsules. The first of the target experiments leading up to these ignition shots will begin in 2008. Targets for the National Ignition Campaign are both complex and precise, and are extraordinarily demanding in materials fabrication, machining, assembly, cryogenics and characterization. An overview of the campaign for ignition will be presented, along with technologies for target fabrication, assembly and metrology and advances in growth and x-ray imaging of DT ice layers. The sum of these efforts represents a quantum leap in target precision, characterization, manufacturing rate and flexibility over current state-of-the-art

  7. New perspectives on auto propane

    International Nuclear Information System (INIS)

    Webb, R.F.

    1991-01-01

    In spite of the high level of propane use in vehicles in North America (relative to the use of compressed natural gas (CNG) or methanol), the alternate-fuel research and development activities of original equipment manufacturers (OEMs) are focusing on methanol, CNG, and electric vehicles. If OEM indifference to propane continues, propane vehicles will continue to be available only in after-market conversions, denying propane the benefits of OEM mass-production economics, quality control, retail distribution, and other factors. Recent developments in auto propane are reported which should be considered by OEMs and policymakers to allow propane to enter the mass-scale motor vehicle market. Propane and the liquefied petroleum gas (LPG) mix used as a motor vehicle fuel are often regarded as just a byproduct of natural gas production and oil refining, giving the impression that propane/LPG will not be available in sufficient quantities to support a mass market. It is shown that LPG supply is market-responsive and that over 20 billion gal of new supply could be made available from North American sources by the year 2000 and over 27 billion gal by 2005, sufficient to supply 12.5% of the projected North American vehicle fleet in 2005. The new supply would come from incremental expansion of existing production, displacement of LPG from lower-value uses, and LPG synthesis. The environmental performance of propane/LPG engines is also compared to that of engines running on gasoline, natural gas, and methanol. Advantages of LPG over gasoline include lower carbon content and lower CO emissions, and advantages over CNG arise from the high greenhouse gas activity and long life of methane. 12 figs

  8. Laser ignition - Spark plug development and application in reciprocating engines

    Science.gov (United States)

    Pavel, Nicolaie; Bärwinkel, Mark; Heinz, Peter; Brüggemann, Dieter; Dearden, Geoff; Croitoru, Gabriela; Grigore, Oana Valeria

    2018-03-01

    Combustion is one of the most dominant energy conversion processes used in all areas of human life, but global concerns over exhaust gas pollution and greenhouse gas emission have stimulated further development of the process. Lean combustion and exhaust gas recirculation are approaches to improve the efficiency and to reduce pollutant emissions; however, such measures impede reliable ignition when applied to conventional ignition systems. Therefore, alternative ignition systems are a focus of scientific research. Amongst others, laser induced ignition seems an attractive method to improve the combustion process. In comparison with conventional ignition by electric spark plugs, laser ignition offers a number of potential benefits. Those most often discussed are: no quenching of the combustion flame kernel; the ability to deliver (laser) energy to any location of interest in the combustion chamber; the possibility of delivering the beam simultaneously to different positions, and the temporal control of ignition. If these advantages can be exploited in practice, the engine efficiency may be improved and reliable operation at lean air-fuel mixtures can be achieved, making feasible savings in fuel consumption and reduction in emission of exhaust gasses. Therefore, laser ignition can enable important new approaches to address global concerns about the environmental impact of continued use of reciprocating engines in vehicles and power plants, with the aim of diminishing pollutant levels in the atmosphere. The technology can also support increased use of electrification in powered transport, through its application to ignition of hybrid (electric-gas) engines, and the efficient combustion of advanced fuels. In this work, we review the progress made over the last years in laser ignition research, in particular that aimed towards realizing laser sources (or laser spark plugs) with dimensions and properties suitable for operating directly on an engine. The main envisaged

  9. Piezoelectrically Initiated Pyrotechnic Igniter

    Science.gov (United States)

    Quince, Asia; Dutton, Maureen; Hicks, Robert; Burnham, Karen

    2013-01-01

    This innovation consists of a pyrotechnic initiator and piezoelectric initiation system. The device will be capable of being initiated mechanically; resisting initiation by EMF, RF, and EMI (electromagnetic field, radio frequency, and electromagnetic interference, respectively); and initiating in water environments and space environments. Current devices of this nature are initiated by the mechanical action of a firing pin against a primer. Primers historically are prone to failure. These failures are commonly known as misfires or hang-fires. In many cases, the primer shows the dent where the firing pin struck the primer, but the primer failed to fire. In devices such as "T" handles, which are commonly used to initiate the blowout of canopies, loss of function of the device may result in loss of crew. In devices such as flares or smoke generators, failure can result in failure to spot a downed pilot. The piezoelectrically initiated ignition system consists of a pyrotechnic device that plugs into a mechanical system (activator), which on activation, generates a high-voltage spark. The activator, when released, will strike a stack of electrically linked piezo crystals, generating a high-voltage, low-amperage current that is then conducted to the pyro-initiator. Within the initiator, an electrode releases a spark that passes through a pyrotechnic first-fire mixture, causing it to combust. The combustion of the first-fire initiates a primary pyrotechnic or explosive powder. If used in a "T" handle, the primary would ramp the speed of burn up to the speed of sound, generating a shock wave that would cause a high explosive to go "high order." In a flare or smoke generator, the secondary would produce the heat necessary to ignite the pyrotechnic mixture. The piezo activator subsystem is redundant in that a second stack of crystals would be struck at the same time with the same activation force, doubling the probability of a first strike spark generation. If the first

  10. Two-stage Lagrangian modeling of ignition processes in ignition quality tester and constant volume combustion chambers

    KAUST Repository

    Alfazazi, Adamu

    2016-08-10

    The ignition characteristics of isooctane and n-heptane in an ignition quality tester (IQT) were simulated using a two-stage Lagrangian (TSL) model, which is a zero-dimensional (0-D) reactor network method. The TSL model was also used to simulate the ignition delay of n-dodecane and n-heptane in a constant volume combustion chamber (CVCC), which is archived in the engine combustion network (ECN) library (http://www.ca.sandia.gov/ecn). A detailed chemical kinetic model for gasoline surrogates from the Lawrence Livermore National Laboratory (LLNL) was utilized for the simulation of n-heptane and isooctane. Additional simulations were performed using an optimized gasoline surrogate mechanism from RWTH Aachen University. Validations of the simulated data were also performed with experimental results from an IQT at KAUST. For simulation of n-dodecane in the CVCC, two n-dodecane kinetic models from the literature were utilized. The primary aim of this study is to test the ability of TSL to replicate ignition timings in the IQT and the CVCC. The agreement between the model and the experiment is acceptable except for isooctane in the IQT and n-heptane and n-dodecane in the CVCC. The ability of the simulations to replicate observable trends in ignition delay times with regard to changes in ambient temperature and pressure allows the model to provide insights into the reactions contributing towards ignition. Thus, the TSL model was further employed to investigate the physical and chemical processes responsible for controlling the overall ignition under various conditions. The effects of exothermicity, ambient pressure, and ambient oxygen concentration on first stage ignition were also studied. Increasing ambient pressure and oxygen concentration was found to shorten the overall ignition delay time, but does not affect the timing of the first stage ignition. Additionally, the temperature at the end of the first stage ignition was found to increase at higher ambient pressure

  11. Shape Analysis Using the Auto Diffusion Function

    DEFF Research Database (Denmark)

    Gebal, Katarzyna; Bærentzen, Jakob Andreas; Aanæs, Henrik

    2009-01-01

    Scalar functions defined on manifold triangle meshes is a starting point for many geometry processing algorithms such as mesh parametrization, skeletonization, and segmentation. In this paper, we propose the Auto Diffusion Function (ADF) which is a linear combination of the eigenfunctions......, it is controlled by a single parameter which can be interpreted as feature scale, and, finally, the ADF is invariant to rigid and isometric deformations. We describe the ADF and its properties in detail and compare it to other choices of scalar functions on manifolds. As an example of an application, we present...

  12. The National Ignition Facility

    International Nuclear Information System (INIS)

    Hogan, W.J.; Moses, E.; Warner, B.; Sorem, M.; Soures, J.M.

    2001-01-01

    The National Ignition Facility (NIF) is the largest construction project ever undertaken at Lawrence Livermore National Laboratory (LLNL). NIF consists of 192 forty-centimeter-square laser beams and a 10-m-diameter target chamber. NIF is being designed and built by an LLNL-led team from Los Alamos National Laboratory, Sandia National Laboratories, the University of Rochester, and LLNL. Physical construction began in 1997. The Laser and Target Area Building and the Optics Assembly Building were the first major construction activities, and despite several unforeseen obstacles, the buildings are now 92% complete and have been done on time and within cost. Prototype component development and testing has proceeded in parallel. Optics vendors have installed full-scale production lines and have done prototype production runs. The assembly and integration of the beampath infrastructure has been reconsidered and a new approach has been developed. This paper will discuss the status of the NIF project and the plans for completion. (author)

  13. The Compact Ignition Tokamak

    International Nuclear Information System (INIS)

    Schmidt, J.

    1987-01-01

    The author discusses his lab's plan for completing the Compact Ignition Tokamak (CIT) conceptual design during calendar year 1987. Around July 1 they froze the subsystem envelopes on the device to continue with the conceptual design. They did this by formalizing a general requirements document. They have been developing the management plan and submitted a version to the DOE July 10. He describes a group of management activities. They released the vacuum vessel Request For Proposals (RFP) on August 5. An RFP to do a major part of the system engineering on the device is being developed. They intend to assemble the device outside of the test cell, then move it into the the test cell, install it there, and bring to the test cell many of the auxiliary facilities from TFTR, for example, power supplies

  14. Control of Flow Structure and Ignition of Hydrocarbon Fuel in Cavity and Behind Wallstep of Supersonic Duct by Filamentary DC Discharge

    Science.gov (United States)

    2011-01-01

    Lindstrom , K.R. Jackson, S. Williams, R. Givens, W.F. Bailey, C.J. Tam, W.F. Terry, AIAA Journal 47, 2368 (2009). 13. S.T. Sanders, J.A. Baldwin, T.P...A. Kuthi, C. Jiang, P. Ronney, and Martin A. Gundersen, ―Transient Plasma Ignition of Quiescent and Flowing Air/Fuel Mixtures‖ IEEE Transactions on...applications at elevated temperature. JQSRT 103 (2007) 565–577. 17. C.D. Lindstrom , K.R. Jackson, S. Williams, R. Givens, W.F. Bailey, C.J. Tam, W.F

  15. Reversed field pinch ignition requirements

    International Nuclear Information System (INIS)

    Werley, K.A.

    1991-01-01

    Plasma models are described and used to calculated numerically the transport confinement (nτ E ) requirements and steady state operation points for both the reversed field pinch (RFP) and the tokamak. The models are used to examine the CIT tokamak ignition conditions and the RFP experimental and ignition conditions. Physics differences between RFPs and tokamaks and their consequences for a D-T ignition machine are discussed. Compared with a tokamak, the ignition RFP has many physics advantages, including Ohmic heating to ignition (no need for auxiliary heating systems), higher beta, lower ignition current, less sensitivity of ignition requirements to impurity effects, no hard disruptions (associated with beta or density limits) and successful operation with high radiation fractions (f RAD ∼ 0.95). These physics advantages, coupled with important engineering advantages associated with lower external magnetic field, larger aspect ratios and smaller plasma cross-sections, translate to significant cost reductions for both ignition and reactor applications. The primary drawback of the RFP is the uncertainty that the present scaling will extrapolate to reactor regimes. Devices that are under construction should go a long way toward resolving this scaling uncertainty. The 4 MA ZTH is expected to extend the nτ E transport scaling data by three orders of magnitude above the results of ZT-40M, and, if the present scaling holds, ZTH is expected to achieve a D-T equivalent scientific energy breakeven, Q = 1. A base case RFP ignition point is identified with a plasma current of 8.1 MA and no auxiliary heating. (author). 19 refs, 11 figs, 3 tabs

  16. The National Ignition Facility. The path to ignition and inertial fusion energy

    International Nuclear Information System (INIS)

    Eric Storm

    2010-01-01

    Complete text of publication follows. The National Ignition Facility (NIF), the world's largest and most energetic laser system built for studying inertial confinement fusion (ICF) and high-energy-density (HED) science, is now operational at Lawrence Livermore National Laboratory (LLNL). NIF's 192 beams are capable of producing 1.8 MJ and 500 TW of ultraviolet light and are configured to create pressures as high as 100 GB, matter temperatures approaching 10 9 and densities over 1000 g/cm 3 . With these capabis70lities, the NIF will enable exploring scientific problems in strategic defense, basic science and fusion energy. One of the early NIF campaigns is focusing on demonstrating laboratory-scale thermonuclear ignition and burn to produce net fusion energy gains of 10-20 with 1.2 to 1.4 MJ of 0.35 μm light. NIF ignition experiments began late in FY2009 as part of the National Ignition Campaign (NIC). Participants of NIC include LLNL, General Atomics, Los Alamos National Laboratory, Sandia National Laboratory, and the University of Rochester Laboratory for Energetics (LLE) as well as variety of national and international collaborators. The results from these initial experiments show great promise for the relatively near-term achievement of ignition. Capsule implosion experiments at energies up to 1.2 MJ have demonstrated laser energetics, radiation temperatures, and symmetry control that scale to ignition conditions. Of particular importance is the demonstration of peak hohlraum temperatures near 300 eV with low overall backscatter less than 10%. Cryogenic target capability and additional diagnostics are being installed in preparation for layered target deuterium-tritium implosions to be conducted later in 2010. The goal for NIC is to demonstrate a predictable fusion experimental platform by the end of 2012. Successful demonstration of ignition and net energy gain on NIF will be a major step towards demonstrating the feasibility of Inertial Fusion Energy (IFE) and

  17. Contactless Electric Igniter for Vehicle to Lower Exhaust Emission and Fuel Consumption

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2014-01-01

    Full Text Available An electric igniter for engine/hybrid vehicles is presented. The igniter comprises a flyback converter, a voltage-stacked capacitor, a PIC-based controller, a differential voltage detector, and an ignition coil, of which structure is non-contact type. Since the electric igniter adopts a capacitor to accumulate energy for engine ignition instead of traditional contacttype approach, it enhances the igniting performance of a spark plug effectively. As a result, combustion efficiency is promoted, fuel consumption is saved, and exhaust emission is reduced. The igniter not only is good for fuel efficiency but also can reduce HC and CO emission significantly, which therefore is an environmentally friendly product. The control core of the igniter is implemented on a single chip, which lowers discrete component count, reduces system volume, and increases reliability. In addition, the ignition timing can be programmed so that a timing regulator can be removed from the proposed system, simplifying its structure. To verify the feasibility and functionality of the igniter, key waveforms are measured and real-car experiments are performed as well.

  18. Shock Tube Ignition Delay Data Affected by Localized Ignition Phenomena

    KAUST Repository

    Javed, Tamour; Badra, J.; Jaasim, Mohammed; Es-sebbar, Et-touhami; Labastida, M.F.; Chung, Suk-Ho; Im, Hong G.; Farooq, Aamir

    2016-01-01

    Shock tubes have conventionally been used for measuring high-temperature ignition delay times ~ O(1 ms). In the last decade or so, the operating regime of shock tubes has been extended to lower temperatures by accessing longer observation times

  19. Whist code calculations of ignition margin in an ignition tokamak

    International Nuclear Information System (INIS)

    Sheffield, J.

    1985-01-01

    A simple global model was developed to determine the ignition margin of tokamaks including electron and ion conduction losses. A comparison of this model with results from a 1 1/2 dimensional Whist code is made

  20. 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.

  1. Fast ignition schemes for inertial confinement fusion

    International Nuclear Information System (INIS)

    Deutsch, C.

    2003-01-01

    The controlled production of a local hot spot in super-compressed deuterium + tritium fuel is examined in details. Relativistic electron beams (REB) in the MeV and proton beams in the few tens MeV energy range produced by PW-lasers are respectively considered. A strong emphasis is given to the propagation issues due to large density gradients in the outer core of compressed fuel. A specific attention is also paid to the final and complete particle stopping resulting in hot spot generation as well as to the interplay of collective vs. particle stopping at the entrance channel on the low density side in plasma target. Moreover, REB production and fast acceleration mechanisms are also given their due attention. Proton fast ignition looks promising as well as the wedged (cone angle) approach circumventing most of transport uncertainties between critical layer and hot spot. Global engineering perspectives for fast ignition scenario (FIS) driven inertial confinement fusion are also detailed. (author)

  2. Transistorized ignition system for internal combustion engines, in particular for vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Mieras, L F; Skay, F

    1977-05-12

    The invention concerns an ignition system for motor vehicles with solid state control of the power transistor switching the primary current of the ignition coil. A pulse generator driven by the engine is used for this, whose voltage pulses control the switching on of the power transistor and increase in a certain ratio to the engine speed. This ensures that the closing angle, i.e. the mechanical angle of rotation which the machine passes through while loading the ignition coil with mechanical energy, is automatically changed so that for low speeds it is just sufficient for certain ignition, but increases with increasing speed, so that the required ignition energy is always available. At low speeds one avoids charging current flowing through the primary winding of the ignition coil for longer than necessary and thus wasting electrical energy.

  3. Direct numerical simulations of the ignition of a lean biodiesel/air mixture with temperature and composition inhomogeneities at high pressure and intermediate temperature

    KAUST Repository

    Luong, Minhbau

    2014-11-01

    The effects of the stratifications of temperature, T, and equivalence ratio, φ{symbol}, on the ignition characteristics of a lean homogeneous biodiesel/air mixture at high pressure and intermediate temperature are investigated using direct numerical simulations (DNSs). 2-D DNSs are performed at a constant volume with the variance of temperature and equivalence ratio (T′ and φ{symbol}′) together with a 2-D isotropic velocity spectrum superimposed on the initial scalar fields. In addition, three different T s(-) φ{symbol} correlations are investigated: (1) baseline cases with T′ only or φ{symbol}′ only, (2) uncorrelated T s(-) φ{symbol} distribution, and (3) negatively-correlated T s(-) φ{symbol} distribution. It is found that the overall combustion is more advanced and the mean heat release rate is more distributed over time with increasing T′ and/or φ{symbol}′ for the baseline and uncorrelated T s(-) φ{symbol} cases. However, the temporal advancement and distribution of the overall combustion caused by T′ or φ{symbol}′ only are nearly annihilated by the negatively-correlated T s(-) φ{symbol} fields. The chemical explosive mode and Damköhler number analyses verify that for the baseline and uncorrelated T s(-) φ{symbol} cases, the deflagration mode is predominant at the reaction fronts for large T′ and/or φ{symbol}′. On the contrary, the spontaneous ignition mode prevails for cases with small T′ or φ{symbol}′, especially for cases with negative T s(-) φ{symbol} correlations, and hence, simultaneous auto-ignition occurs throughout the entire domain, resulting in an excessive rate of heat release. It is also found that turbulence with large intensity, u′, and a short time scale can effectively smooth out initial thermal and compositional fluctuations such that the overall combustion is induced primarily by spontaneous ignition. Based on the present DNS results, the generalization of the effects of T′, φ{symbol}′, and u

  4. Ignition of Aluminum Particles and Clouds

    Energy Technology Data Exchange (ETDEWEB)

    Kuhl, A L; Boiko, V M

    2010-04-07

    Here we review experimental data and models of the ignition of aluminum (Al) particles and clouds in explosion fields. The review considers: (i) ignition temperatures measured for single Al particles in torch experiments; (ii) thermal explosion models of the ignition of single Al particles; and (iii) the unsteady ignition Al particles clouds in reflected shock environments. These are used to develop an empirical ignition model appropriate for numerical simulations of Al particle combustion in shock dispersed fuel explosions.

  5. AutoCAD platform customization VBA

    CERN Document Server

    Ambrosius, Lee

    2015-01-01

    Boost productivity and streamline your workflow with expert AutoCAD: VBA programming instruction AutoCAD Platform Customization: VBA is the definitive guide to personalizing AutoCAD and the various programs that run on the AutoCAD platform, including AutoCAD Architecture, Civil 3D, Plant 3D, and more. Written by an Autodesk insider with years of customization and programming experience, this book features detailed discussions backed by real-world examples and easy-to-follow tutorials that illustrate each step in the personalization process. Readers gain expert guidance toward managing layout

  6. AutoCAD 2014 for dummies

    CERN Document Server

    Fane, Bill

    2013-01-01

    Find your way around AutoCAD 2014 with this full-color, For Dummies guide!Put away that pencil and paper and start putting the power of AutoCAD 2014 to work in your CAD projects and designs. From setting up your drawing environment to using text, dimensions, hatching, and more, this guide walks you through AutoCAD basics and provides you with a solid understanding of the latest CAD tools and techniques. You'll also benefit from the full-color illustrations that mirror exactly what you'll see on your AutoCAD 2014 screen and highlight the importance of AutoCAD's Mode

  7. AutoCAD 2008 for dummies

    CERN Document Server

    Byrnes, David

    2007-01-01

    A gentle, humorous introduction to this fearsomely complex software that helps new users start creating 2D and 3D technical drawings right awayCovers the new features and enhancements in the latest AutoCAD version and provides coverage of AutoCAD LT, AutoCAD''s lower-cost siblingTopics covered include creating a basic layout, using AutoCAD DesignCenter, drawing and editing, working with dimensions, plotting, using blocks, adding text to drawings, and drawing on the InternetAutoCAD is the leading CAD software for architects, engineers, and draftspeople who need to create detailed 2D and 3D tech

  8. AutoCAD platform customization autolisp

    CERN Document Server

    Ambrosius, Lee

    2014-01-01

    Customize and personalize programs built on the AutoCAD platform AutoLISP is the key to unlocking the secrets of a more streamlined experience using industry leading software programs like AutoCAD, Civil 3D, Plant 3D, and more. AutoCAD Platform Customization: AutoLISP provides real-world examples that show you how to do everything from modifying graphical objects and reading and setting system variables to communicating with external programs. It also features a resources appendix and downloadable datasets and customization examples-tools that ensure swift and easy adoption. Find out how to r

  9. The Application of Auto-Disturbance Rejection Control Optimized by Least Squares Support Vector Machines Method and Time-Frequency Representation in Voltage Source Converter-High Voltage Direct Current System.

    Science.gov (United States)

    Liu, Ying-Pei; Liang, Hai-Ping; Gao, Zhong-Ke

    2015-01-01

    In order to improve the performance of voltage source converter-high voltage direct current (VSC-HVDC) system, we propose an improved auto-disturbance rejection control (ADRC) method based on least squares support vector machines (LSSVM) in the rectifier side. Firstly, we deduce the high frequency transient mathematical model of VSC-HVDC system. Then we investigate the ADRC and LSSVM principles. We ignore the tracking differentiator in the ADRC controller aiming to improve the system dynamic response speed. On this basis, we derive the mathematical model of ADRC controller optimized by LSSVM for direct current voltage loop. Finally we carry out simulations to verify the feasibility and effectiveness of our proposed control method. In addition, we employ the time-frequency representation methods, i.e., Wigner-Ville distribution (WVD) and adaptive optimal kernel (AOK) time-frequency representation, to demonstrate our proposed method performs better than the traditional method from the perspective of energy distribution in time and frequency plane.

  10. The Application of Auto-Disturbance Rejection Control Optimized by Least Squares Support Vector Machines Method and Time-Frequency Representation in Voltage Source Converter-High Voltage Direct Current System.

    Directory of Open Access Journals (Sweden)

    Ying-Pei Liu

    Full Text Available In order to improve the performance of voltage source converter-high voltage direct current (VSC-HVDC system, we propose an improved auto-disturbance rejection control (ADRC method based on least squares support vector machines (LSSVM in the rectifier side. Firstly, we deduce the high frequency transient mathematical model of VSC-HVDC system. Then we investigate the ADRC and LSSVM principles. We ignore the tracking differentiator in the ADRC controller aiming to improve the system dynamic response speed. On this basis, we derive the mathematical model of ADRC controller optimized by LSSVM for direct current voltage loop. Finally we carry out simulations to verify the feasibility and effectiveness of our proposed control method. In addition, we employ the time-frequency representation methods, i.e., Wigner-Ville distribution (WVD and adaptive optimal kernel (AOK time-frequency representation, to demonstrate our proposed method performs better than the traditional method from the perspective of energy distribution in time and frequency plane.

  11. Advanced ignition for automotive engines

    OpenAIRE

    Pineda, Daniel Ivan

    2017-01-01

    Spark plugs have been igniting combustible mixtures like those found in automotive engines for over a century, and the principles of the associated ignition techniques using thermal plasma (inductive or capacitive sparks) have remained relatively unchanged during that time. However, internal combustion engines are increasingly operating with boosted intake pressures (i.e. turbo- or super-charged) in order to maintain power output while simultaneously reducing engine size and weight, and they ...

  12. The National Ignition Facility Project

    International Nuclear Information System (INIS)

    Paisner, J.A.; Campbell, E.M.; Hogan, W.J.

    1994-01-01

    The mission of the National Ignition Facility is to achieve ignition and gain in inertial confinement fusion targets in the laboratory. The facility will be used for defense applications such as weapons physics and weapons effects testing, and for civilian applications such as fusion energy development and fundamental studies of matter at high temperatures and densities. This paper reviews the design, schedule, and costs associated with the construction project

  13. The National Ignition Facility Project

    International Nuclear Information System (INIS)

    Paisner, J.A.; Campbell, E.M.; Hogan, W.J.

    1994-01-01

    The mission of the National Ignition Facility is to achieve ignition and gain in ICF targets in the laboratory. The facility will be used for defense applications such as weapons physics and weapons effect testing, and for civilian applications such as fusion energy development and fundamental studies of matter at high temperatures and densities. This paper reviews the design, schedule and costs associated with the construction project

  14. 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

  15. Development of fast ignition integrated interconnecting code (FI3) for fast ignition scheme

    International Nuclear Information System (INIS)

    Nagatomo, H.; Johzaki, T.; Mima, K.; Sunahara, A.; Nishihara, K.; Izawa, Y.; Sakagami, H.; Nakao, Y.; Yokota, T.; Taguchi, T.

    2005-01-01

    The numerical simulation plays an important role in estimating the feasibility and performance of the fast ignition. There are two key issues in numerical analysis for the fast ignition. One is the controlling the implosion dynamics to form a high density core plasma in non-spherical implosion, and the other is heating core plasma efficiency by the short pulse high intense laser. From initial laser irradiation to final fusion burning, all the physics are coupling strongly in any phase, and they must be solved consistently in computational simulation. However, in general, it is impossible to simulate laser plasma interaction and radiation hydrodynamics in a single computational code, without any numerical dissipation, special assumption or conditional treatment. Recently, we have developed 'Fast Ignition Integrated Interconnecting code' (FI 3 ) which consists of collective Particle-in-Cell code, Relativistic Fokker-Planck hydro code, and 2-dimensional radiation hydrodynamics code. And those codes are connecting with each other in data-flow bases. In this paper, we will present detail feature of the FI 3 code, and numerical results of whole process of fast ignition. (author)

  16. Ignition inhibitors for cellulosic materials

    International Nuclear Information System (INIS)

    Alvares, N.J.

    1976-01-01

    By exposing samples to various irradiance levels from a calibrated thermal radiation source, the ignition responses of blackened alpha-cellulose and cotton cloth with and without fire-retardant additives were compared. Samples treated with retardant compounds which showed the most promise were then isothermally pyrolyzed in air for comparisons between the pyrolysis rates. Alpha-cellulose samples containing a mixture of boric acid, borax, and ammonium di-hydrogen phosphate could not be ignited by irradiances up to 4.0 cal cm -2 s-1 (16.7 W/cm 2 ). At higher irradiances the specimens ignited, but flaming lasted only until the flammable gases were depleted. Cotton cloth containing a polymeric retardant with the designation THPC + MM was found to be ignition-resistant to all irradiances below 7.0 cal cm -2 s -1 (29.3 W/cm 2 ). Comparison of the pyrolysis rates of the retardant-treated alpha-cellulose and the retardant-treated cotton showed that the retardant mechanism is qualitatively the same. Similar ignition-response measurements were also made with specimens exposed to ionizing radiation. It was observed that gamma radiation results in ignition retardance of cellulose, while irradiation by neutrons does not

  17. Cyclopentane combustion. Part II. Ignition delay measurements and mechanism validation

    KAUST Repository

    Rachidi, Mariam El

    2017-06-12

    This study reports cyclopentane ignition delay measurements over a wide range of conditions. The measurements were obtained using two shock tubes and a rapid compression machine, and were used to test a detailed low- and high-temperature mechanism of cyclopentane oxidation that was presented in part I of this study (Al Rashidi et al., 2017). The ignition delay times of cyclopentane/air mixtures were measured over the temperature range of 650–1350K at pressures of 20 and 40atm and equivalence ratios of 0.5, 1.0 and 2.0. The ignition delay times simulated using the detailed chemical kinetic model of cyclopentane oxidation show very good agreement with the experimental measurements, as well as with the cyclopentane ignition and flame speed data available in the literature. The agreement is significantly improved compared to previous models developed and investigated at higher temperatures. Reaction path and sensitivity analyses were performed to provide insights into the ignition-controlling chemistry at low, intermediate and high temperatures. The results obtained in this study confirm that cycloalkanes are less reactive than their non-cyclic counterparts. Moreover, cyclopentane, a high octane number and high octane sensitivity fuel, exhibits minimal low-temperature chemistry and is considerably less reactive than cyclohexane. This study presents the first experimental low-temperature ignition delay data of cyclopentane, a potential fuel-blending component of particular interest due to its desirable antiknock characteristics.

  18. Cyclopentane combustion. Part II. Ignition delay measurements and mechanism validation

    KAUST Repository

    Rachidi, Mariam El; Má rmol, Juan C.; Banyon, Colin; Sajid, Muhammad Bilal; Mehl, Marco; Pitz, William J.; Mohamed, Samah; Alfazazi, Adamu; Lu, Tianfeng; Curran, Henry J.; Farooq, Aamir; Sarathy, Mani

    2017-01-01

    This study reports cyclopentane ignition delay measurements over a wide range of conditions. The measurements were obtained using two shock tubes and a rapid compression machine, and were used to test a detailed low- and high-temperature mechanism of cyclopentane oxidation that was presented in part I of this study (Al Rashidi et al., 2017). The ignition delay times of cyclopentane/air mixtures were measured over the temperature range of 650–1350K at pressures of 20 and 40atm and equivalence ratios of 0.5, 1.0 and 2.0. The ignition delay times simulated using the detailed chemical kinetic model of cyclopentane oxidation show very good agreement with the experimental measurements, as well as with the cyclopentane ignition and flame speed data available in the literature. The agreement is significantly improved compared to previous models developed and investigated at higher temperatures. Reaction path and sensitivity analyses were performed to provide insights into the ignition-controlling chemistry at low, intermediate and high temperatures. The results obtained in this study confirm that cycloalkanes are less reactive than their non-cyclic counterparts. Moreover, cyclopentane, a high octane number and high octane sensitivity fuel, exhibits minimal low-temperature chemistry and is considerably less reactive than cyclohexane. This study presents the first experimental low-temperature ignition delay data of cyclopentane, a potential fuel-blending component of particular interest due to its desirable antiknock characteristics.

  19. [Stress and auto-immunity].

    Science.gov (United States)

    Delévaux, I; Chamoux, A; Aumaître, O

    2013-08-01

    The etiology of auto-immune disorders is multifactorial. Stress is probably a participating factor. Indeed, a high proportion of patients with auto-immune diseases report uncommon stress before disease onset or disease flare. The biological consequences of stress are increasingly well understood. Glucocorticoids and catecholamines released by hypothalamic-pituitary-adrenal axis during stress will alter the balance Th1/Th2 and the balance Th17/Treg. Stress impairs cellular immunity, decreases immune tolerance and stimulates humoral immunity exposing individuals to autoimmune disease among others. The treatment for autoimmune disease should include stress management. Copyright © 2012 Société nationale française de médecine interne (SNFMI). Published by Elsevier SAS. All rights reserved.

  20. The National Ignition Facility (NIF): A path to fusion energy

    International Nuclear Information System (INIS)

    Moses, Edward I.

    2008-01-01

    Fusion energy has long been considered a promising, clean, nearly inexhaustible source of energy. Power production by fusion micro-explosions of inertial confinement fusion (ICF) targets has been a long-term research goal since the invention of the first laser in 1960. The National Ignition Facility (NIF) is poised to take the next important step in the journey by beginning experiments researching ICF ignition. Ignition on NIF will be the culmination of over 30 years of ICF research on high-powered laser systems such as the Nova laser at Lawrence Livermore National Laboratory (LLNL) and the OMEGA laser at the University of Rochester, as well as smaller systems around the world. NIF is a 192-beam Nd-glass laser facility at LLNL that is more than 90% complete. The first cluster of 48 beams is operational in the laser bay, the second cluster is now being commissioned, and the beam path to the target chamber is being installed. The Project will be completed in 2009, and ignition experiments will start in 2010. When completed, NIF will produce up to 1.8 MJ of 0.35-μm light in highly shaped pulses required for ignition. It will have beam stability and control to higher precision than any other laser fusion facility. Experiments using one of the beams of NIF have demonstrated that NIF can meet its beam performance goals. The National Ignition Campaign (NIC) has been established to manage the ignition effort on NIF. NIC has all of the research and development required to execute the ignition plan and to develop NIF into a fully operational facility. NIF will explore the ignition space, including direct drive, 2ω ignition, and fast ignition, to optimize target efficiency for developing fusion as an energy source. In addition to efficient target performance, fusion energy requires significant advances in high-repetition-rate lasers and fusion reactor technology. The Mercury laser at LLNL is a high-repetition-rate Nd-glass laser for fusion energy driver development. Mercury

  1. Numerical and Experimental Study on the Combustion and Emission Characteristics of a Dimethyl Ether (DME Fueled Compression Ignition Engine Études numériques et expérimentales sur les caractéristiques de combustion et d’émissions d’un éther diméthylique (EDM- moteur à auto-allumage rempli de combustible

    Directory of Open Access Journals (Sweden)

    Kim Hyung Jun

    2012-05-01

    Full Text Available A numerical investigation was carried out to study on the combustion and emission characteristics of dimethyl ether (DME with wide ranges of injection timings in compression ignition engines. In order to simulate DME combustion processes, a KIVA-3V code coupled with a chemistry solver was used to solve the detailed chemical kinetics model of DME oxidation. In addition, the Kelvin-Helmholtz-Rayleigh-Taylor (KH-RT hybrid breakup model and Renormalization Group (RNG k-ε  models were applied to analyze the spray characteristics and turbulent flow, respectively. To predict the NOx formation during DME combustion, a reduced Gas Research Institute (GRI NO mechanism was used. From these results on the combustion and emission, the calculated results were compared with experimental ones for the same operating conditions. In the combustion characteristics, the calculated combustion pressure and heat release rates agreed well with experimental results. The levels of experimental NOx emissions was reduced as the start of the injection timing retarded, and also these trends appeared in calculated emission characteristics. Additionally, the calculated CO and HC emissions show an increasing trend as the start of the injection is retarded. Dans cette étude, nous considérons la simulation de la combustion du dimethyl ether (DME dans un moteur à allumage par compression. Les caractéristiques de la combustion ainsi que les émissions polluantes sont analysées sur une large gamme d’avance à l’injection. Afin de simuler le processus de combustion du EDM, le code KIVA-3V couplé à un solveur chimique a été utilisé pour résoudre la cinétique détaillée de l’oxydation du EDM. Le modèle de rupture de Kelvin-Helmholtz-Rayleigh- Taylor (KH-RT ainsi que le modèle de turbulence k-ε  RNG ont été appliqués pour analyser respectivement les caractéristiques du jet et l’écoulement turbulent. Pour prévoir la formation de NOx pendant la combustion

  2. Fast ignition breakeven scaling

    International Nuclear Information System (INIS)

    Slutz, Stephen A.; Vesey, Roger Alan

    2005-01-01

    A series of numerical simulations have been performed to determine scaling laws for fast ignition break even of a hot spot formed by energetic particles created by a short pulse laser. Hot spot break even is defined to be when the fusion yield is equal to the total energy deposited in the hot spot through both the initial compression and the subsequent heating. In these simulations, only a small portion of a previously compressed mass of deuterium-tritium fuel is heated on a short time scale, i.e., the hot spot is tamped by the cold dense fuel which surrounds it. The hot spot tamping reduces the minimum energy required to obtain break even as compared to the situation where the entire fuel mass is heated, as was assumed in a previous study [S. A. Slutz, R. A. Vesey, I. Shoemaker, T. A. Mehlhorn, and K. Cochrane, Phys. Plasmas 7, 3483 (2004)]. The minimum energy required to obtain hot spot break even is given approximately by the scaling law E T = 7.5(ρ/100) -1.87 kJ for tamped hot spots, as compared to the previously reported scaling of E UT = 15.3(ρ/100) -1.5 kJ for untamped hotspots. The size of the compressed fuel mass and the focusability of the particles generated by the short pulse laser determines which scaling law to use for an experiment designed to achieve hot spot break even

  3. IGNITION IMPROVEMENT OF LEAN NATURAL GAS MIXTURES

    Energy Technology Data Exchange (ETDEWEB)

    Jason M. Keith

    2005-02-01

    This report describes work performed during a thirty month project which involves the production of dimethyl ether (DME) on-site for use as an ignition-improving additive in a compression-ignition natural gas engine. A single cylinder spark ignition engine was converted to compression ignition operation. The engine was then fully instrumented with a cylinder pressure transducer, crank shaft position sensor, airflow meter, natural gas mass flow sensor, and an exhaust temperature sensor. Finally, the engine was interfaced with a control system for pilot injection of DME. The engine testing is currently in progress. In addition, a one-pass process to form DME from natural gas was simulated with chemical processing software. Natural gas is reformed to synthesis gas (a mixture of hydrogen and carbon monoxide), converted into methanol, and finally to DME in three steps. Of additional benefit to the internal combustion engine, the offgas from the pilot process can be mixed with the main natural gas charge and is expected to improve engine performance. Furthermore, a one-pass pilot facility was constructed to produce 3.7 liters/hour (0.98 gallons/hour) DME from methanol in order to characterize the effluent DME solution and determine suitability for engine use. Successful production of DME led to an economic estimate of completing a full natural gas-to-DME pilot process. Additional experimental work in constructing a synthesis gas to methanol reactor is in progress. The overall recommendation from this work is that natural gas to DME is not a suitable pathway to improved natural gas engine performance. The major reasons are difficulties in handling DME for pilot injection and the large capital costs associated with DME production from natural gas.

  4. Fuels for homogeneous charge compression ignition (HCCI) engines. Automotive fuels survey. Part 6

    Energy Technology Data Exchange (ETDEWEB)

    Van Walwijk, M.

    2001-01-01

    Homogeneous charge compression ignition (HCCI) is a third mode of operation for internal combustion engines, beside spark ignition and conventional compression ignition. This report concentrates on the requirements that HCCI operation puts on fuels for these engines. For readers with limited time available, this summary describes the main findings. Policy makers that need some more background information may turn directly to chapter 7, 'Fuels for HCCI engines'. The rest of this report can be considered as a reference guide for more detailed information. The driving force to investigate HCCI engines is the potential of low emissions and simultaneously high energy efficiency. HCCI is gaining attention the last few years. However, HCCI engines are still in the research phase. After many experiments with prototype engines, people have now started working on computer simulations of the combustion process, to obtain a fundamental understanding of HCCI combustion and to steer future engine developments. In HCCI engines, an air/fuel mixture is prepared before it enters the combustion chamber. The homogeneous mixture is in the combustion chamber compressed to auto-ignition. Unlike in conventional engines, combustion starts at many different locations simultaneously and the speed of combustion is very high, so there is no flame front. Lean air/fuel mixtures (excess air) are used to control combustion speed. Because of the excess air, combustion temperature is relatively low, resulting in low NOx emissions. When the fuel is vaporised to a truly homogeneous mixture, complete combustion results in low particulate emissions. The most important advantages of HCCI engines are: - Emissions of NOx and particulates are very low. - Energy efficiency is high. It is comparable to diesel engines. - Many different fuels (one at a time) can be used in the HCCI concept. There are also some hurdles to overcome: - Controlling combustion is difficult, it complicates engine design

  5. Diethyl Ether as an Ignition Enhancer for Naphtha Creating a Drop in Fuel for Diesel

    KAUST Repository

    Vallinayagam, R.

    2016-12-01

    Direct use of naphtha in compression ignition (CI) engines is not advisable because its lower cetane number negatively impacts the auto ignition process. However, engine or fuel modifications can be made to operate naphtha in CI engines. Enhancing a fuel’s auto ignition characteristics presents an opportunity to use low cetane fuel, naphtha, in CI engines. In this research, Di-ethyl ether (DEE) derived from ethanol is used as an ignition enhancer for light naphtha. With this fuel modification, a “drop-in” fuel that is interchangeable with existing diesel fuel has been created. The ignition characteristics of DEE blended naphtha were studied in an ignition quality tester (IQT); the measured ignition delay time (IDT) for pure naphtha was 6.9 ms. When DEE was added to naphtha, IDT decreased and D30 (30% DEE + 70% naphtha) showed comparable IDT with US NO.2 diesel. The derived cetane number (DCN) of naphtha, D10 (10% DEE + 90% naphtha), D20% DEE + 80% naphtha) and D30 were measured to be 31, 37, 40 and 49, respectively. The addition of 30% DEE in naphtha achieved a DCN equivalent to US NO.2 diesel. Subsequent experiments in a CI engine exhibited longer ignition delay for naphtha compared to diesel. The peak in-cylinder pressure is higher for naphtha than diesel and other tested fuels. When DEE was added to naphtha, the ignition delay shortened and peak in-cylinder pressure is reduced. A 3.7% increase in peak in-cylinder pressure was observed for naphtha compared to US NO.2 diesel, while D30 showed comparable results with diesel. The pressure rise rate dropped with the addition of DEE to naphtha, thereby reducing the ringing intensity. Naphtha exhibited a peak heat release rate of 280 kJ/m3deg, while D30 showed a comparable peak heat release rate to US NO.2 diesel. The amount of energy released during the premixed combustion phase decreased with the increase of DEE in naphtha. Thus, this study demonstrates the suitability of DEE blended naphtha mixtures as a

  6. Diethyl Ether as an Ignition Enhancer for Naphtha Creating a Drop in Fuel for Diesel

    KAUST Repository

    Vallinayagam, R.; Vedharaj, S.; Sarathy, Mani; Dibble, Robert W.

    2016-01-01

    Direct use of naphtha in compression ignition (CI) engines is not advisable because its lower cetane number negatively impacts the auto ignition process. However, engine or fuel modifications can be made to operate naphtha in CI engines. Enhancing a fuel’s auto ignition characteristics presents an opportunity to use low cetane fuel, naphtha, in CI engines. In this research, Di-ethyl ether (DEE) derived from ethanol is used as an ignition enhancer for light naphtha. With this fuel modification, a “drop-in” fuel that is interchangeable with existing diesel fuel has been created. The ignition characteristics of DEE blended naphtha were studied in an ignition quality tester (IQT); the measured ignition delay time (IDT) for pure naphtha was 6.9 ms. When DEE was added to naphtha, IDT decreased and D30 (30% DEE + 70% naphtha) showed comparable IDT with US NO.2 diesel. The derived cetane number (DCN) of naphtha, D10 (10% DEE + 90% naphtha), D20% DEE + 80% naphtha) and D30 were measured to be 31, 37, 40 and 49, respectively. The addition of 30% DEE in naphtha achieved a DCN equivalent to US NO.2 diesel. Subsequent experiments in a CI engine exhibited longer ignition delay for naphtha compared to diesel. The peak in-cylinder pressure is higher for naphtha than diesel and other tested fuels. When DEE was added to naphtha, the ignition delay shortened and peak in-cylinder pressure is reduced. A 3.7% increase in peak in-cylinder pressure was observed for naphtha compared to US NO.2 diesel, while D30 showed comparable results with diesel. The pressure rise rate dropped with the addition of DEE to naphtha, thereby reducing the ringing intensity. Naphtha exhibited a peak heat release rate of 280 kJ/m3deg, while D30 showed a comparable peak heat release rate to US NO.2 diesel. The amount of energy released during the premixed combustion phase decreased with the increase of DEE in naphtha. Thus, this study demonstrates the suitability of DEE blended naphtha mixtures as a

  7. High speed auto-charging system for condenser bank

    International Nuclear Information System (INIS)

    Mizuno, Yasunori; Bito, Fumio; Fujita, Kazuhiko; Sometani, Taro

    1987-01-01

    A current-control type high-speed charging system, which is intended for auto-charging of the condenser bank, is developed. Moreover, the system can also serve to compensate the current leakage from the condenser bank so that the charged voltage can be kept constant. The system consists of a sequence circuit, a charging current control circuit (or auto-charging circuit) and a charging circuit. The auto-charging circuit is characterized by the use of a triac to control the current. The current, controlled by the circuit, is supplied to the condenser bank through a step-up transformer and voltage doubler rectifier circuit. It is demonstrated that the use of the high-speed auto-charging circuit can largely decrease the required charging time, compared to constant voltage charging. In addition, the compensation function is shown to serve effectively for maintaining a constant voltage after the completion of charging. The required charging time is decreases as the charging current increases. The maximum charging current is decided by the rating of the traic and the current rating of the rectifier diode in the secondary circuit. Major components of these circuits have decreased impedances to minimize the effect of noise, so that the possibility of an accident can be eliminated. Other various improvements are made in the grounding circuit and the charging protection circuit in order to ensure safety. (Nogami, K.)

  8. Direct numerical simulations of the ignition of a lean biodiesel/air mixture with temperature and composition inhomogeneities at high pressure and intermediate temperature

    KAUST Repository

    Luong, Minhbau; Lu, Tianfeng; Chung, Suk-Ho; Yoo, Chun Sang

    2014-01-01

    is predominant at the reaction fronts for large T′ and/or φ{symbol}′. On the contrary, the spontaneous ignition mode prevails for cases with small T′ or φ{symbol}′, especially for cases with negative T s(-) φ{symbol} correlations, and hence, simultaneous auto

  9. Progress Toward Ignition on the National Ignition Facility

    International Nuclear Information System (INIS)

    Kauffman, R.L.

    2011-01-01

    The principal approach to ignition on the National Ignition Facility (NIF) is indirect drive. A schematic of an ignition target is shown in Figure 1. The laser beams are focused through laser entrance holes at each end of a high-Z cylindrical case, or hohlraum. The lasers irradiate the hohlraum walls producing x-rays that ablate and compress the fuel capsule in the center of the hohlraum. The hohlraum is made of Au, U, or other high-Z material. For ignition targets, the hohlraum is ∼0.5 cm diameter by ∼1 cm in length. The hohlraum absorbs the incident laser energy producing x-rays for symmetrically imploding the capsule. The fuel capsule is a ∼2-mm-diameter spherical shell of CH, Be, or C filled with DT fuel. The DT fuel is in the form of a cryogenic layer on the inside of the capsule. X-rays ablate the outside of the capsule, producing a spherical implosion. The imploding shell stagnates in the center, igniting the DT fuel. NIC has overseen installation of all of the hardware for performing ignition experiments, including commissioning of approximately 50 diagnostic systems in NIF. The diagnostics measure scattered optical light, x-rays from the hohlraum over the energy range from 100 eV to 500 keV, and x-rays, neutrons, and charged particles from the implosion. An example of a diagnostic is the Magnetic Recoil Spectrometer (MRS) built by a collaboration of scientists from MIT, UR-LLE, and LLNL shown in Figure 2. MRS measures the neutron spectrum from the implosion, providing information on the neutron yield and areal density that are metrics of the quality of the implosion. Experiments on NIF extend ICF research to unexplored regimes in target physics. NIF can produce more than 50 times the laser energy and more than 20 times the power of any previous ICF facility. Ignition scale hohlraum targets are three to four times larger than targets used at smaller facilities, and the ignition drive pulses are two to five times longer. The larger targets and longer

  10. Review: laser ignition for aerospace propulsion

    Directory of Open Access Journals (Sweden)

    Steven A. O’Briant

    2016-03-01

    This paper aims to provide the reader an overview of advanced ignition methods, with an emphasis on laser ignition and its applications to aerospace propulsion. A comprehensive review of advanced ignition systems in aerospace applications is performed. This includes studies on gas turbine applications, ramjet and scramjet systems, and space and rocket applications. A brief overview of ignition and laser ignition phenomena is also provided in earlier sections of the report. Throughout the reading, research papers, which were presented at the 2nd Laser Ignition Conference in April 2014, are mentioned to indicate the vast array of projects that are currently being pursued.

  11. Design of ignition targets for the National Ignition Facility

    International Nuclear Information System (INIS)

    Haan, S.W.; Dittrich, T.R.; Marinak, M.M.; Hinkel, D.E.

    1999-01-01

    This is a brief update on the work being done to design ignition targets for the National Ignition Facility. Updates are presented on three areas of current activity : improvements in modeling, work on a variety of targets spanning the parameter space of possible ignition targets ; and the setting of specifications for target fabrication and diagnostics. Highlights of recent activity include : a simulation of the Rayleigh-Taylor instability growth on an imploding capsule, done in 3D on a 72degree by 72degree wedge, with enough zones to resolve modes out to 100 ; and designs of targets at 250eV and 350eV, as well as the baseline 300 eV ; and variation of the central DT gas density, which influences both the Rayleigh-Taylor growth and the smoothness of the DT ice layer

  12. Shock ignition of high gain inertial fusion capsules

    International Nuclear Information System (INIS)

    Schurtz, G.; Ribeyre, X.; Lebel, E.; Casner, A.

    2010-01-01

    the theoretical approach of SI, and Lafon et al. established its gain curves using an extension of the Rosen Lindl model. The efficiency of shock ignition comes from the fact that, unlike conventional central ignition, the final fuel assembly is not isobaric, i.e., the low density hot spot pressure significantly exceeds the pressure of the surrounding cold dense fuel. This high hot spot pressure is obtained from two pressure amplification stages: the first amplification mechanism is spherical convergence. A converging shock increases its strength as C 0.9 where C is the shock convergence ratio. A second amplification stage occurs when the ignition shock collides with the outward directed shock that results from the shell stagnation at target centre. Under optimal matching conditions, shock collision produces a x 6 amplification of pressure. We discuss in the presentation the conditions for the obtention of optimal pressure amplification, at first by studying the ignition window in the space spanned by laser power and launching time, and secondly by modelling the relation ship between the laser intensity required for shock production and the implosion velocity. This latter study indicates a sensible safety trade off using a 250 km/s implosion velocity and a laser spike of ∼ 5 x 10 15 W/cm 2 for the shock production. First kinetic calculations and implosion experiments indicate that laser plasma interaction in the regime of shock ignition may remain under control, provided that the SRS generated hot electrons energy stay below 80 keV. Shock Ignition has been proposed as the baseline of the HiPER project and shock ignition experiments have been proposed on the National Ignition Facility with gains expected between 60 and 100 at laser energies below 500 kJ. Acknowledgments. This work is partly supported by the Aquitaine Region Council.

  13. Enhanced Model for Fast Ignition

    Energy Technology Data Exchange (ETDEWEB)

    Mason, Rodney J. [Research Applications Corporation, Los Alamos, NM (United States)

    2010-10-12

    Laser Fusion is a prime candidate for alternate energy production, capable of serving a major portion of the nation's energy needs, once fusion fuel can be readily ignited. Fast Ignition may well speed achievement of this goal, by reducing net demands on laser pulse energy and timing precision. However, Fast Ignition has presented a major challenge to modeling. This project has enhanced the computer code ePLAS for the simulation of the many specialized phenomena, which arise with Fast Ignition. The improved code has helped researchers to understand better the consequences of laser absorption, energy transport, and laser target hydrodynamics. ePLAS uses efficient implicit methods to acquire solutions for the electromagnetic fields that govern the accelerations of electrons and ions in targets. In many cases, the code implements fluid modeling for these components. These combined features, "implicitness and fluid modeling," can greatly facilitate calculations, permitting the rapid scoping and evaluation of experiments. ePLAS can be used on PCs, Macs and Linux machines, providing researchers and students with rapid results. This project has improved the treatment of electromagnetics, hydrodynamics, and atomic physics in the code. It has simplified output graphics, and provided new input that avoids the need for source code access by users. The improved code can now aid university, business and national laboratory users in pursuit of an early path to success with Fast Ignition.

  14. The national ignition facility (NIF) : A path to fusion energy

    International Nuclear Information System (INIS)

    Moses, E. I.

    2007-01-01

    Fusion energy has long been considered a promising clean, nearly inexhaustible source of energy. Power production by fusion micro-explosions of inertial confinement fusion (ICF) targets has been a long term research goal since the invention of the first laser in 1960. The NIF is poised to take the next important step in the journey by beginning experiments researching ICF ignition. Ignition on NIF will be the culmination of over thirty years of ICF research on high-powered laser systems such as the Nova laser at LLNL and the OMEGA laser at the University of Rochester as well as smaller systems around the world. NIF is a 192 beam Nd-glass laser facility at LLNL that is more than 90% complete. The first cluster of 48 beams is operational in the laser bay, the second cluster is now being commissioned, and the beam path to the target chamber is being installed. The Project will be completed in 2009 and ignition experiments will start in 2010. When completed NIF will produce up to 1.8 MJ of 0.35 μm light in highly shaped pulses required for ignition. It will have beam stability and control to higher precision than any other laser fusion facility. Experiments using one of the beams of NIF have demonstrated that NIF can meet its beam performance goals. The National Ignition Campaign (NIC) has been established to manage the ignition effort on NIF. NIC has all of the research and development required to execute the ignition plan and to develop NIF into a fully operational facility. NIF will explore the ignition space, including direct drive, 2ω ignition, and fast ignition, to optimize target efficiency for developing fusion as an energy source. In addition to efficient target performance, fusion energy requires significant advances in high repetition rate lasers and fusion reactor technology. The Mercury laser at LLNL is a high repetition rate Nd-glass laser for fusion energy driver development. Mercury uses state-o-the art technology such as ceramic laser slabs and light

  15. An Auto-Tuning PI Control System for an Open-Circuit Low-Speed Wind Tunnel Designed for Greenhouse Technology.

    Science.gov (United States)

    Espinoza, Karlos; Valera, Diego L; Torres, José A; López, Alejandro; Molina-Aiz, Francisco D

    2015-08-12

    Wind tunnels are a key experimental tool for the analysis of airflow parameters in many fields of application. Despite their great potential impact on agricultural research, few contributions have dealt with the development of automatic control systems for wind tunnels in the field of greenhouse technology. The objective of this paper is to present an automatic control system that provides precision and speed of measurement, as well as efficient data processing in low-speed wind tunnel experiments for greenhouse engineering applications. The system is based on an algorithm that identifies the system model and calculates the optimum PI controller. The validation of the system was performed on a cellulose evaporative cooling pad and on insect-proof screens to assess its response to perturbations. The control system provided an accuracy of integrated software unit that manages the tests in terms of airflow speed and pressure drop set points.

  16. Options for an ignited tokamak

    International Nuclear Information System (INIS)

    Sheffield, J.

    1984-02-01

    It is expected that the next phase of the fusion program will involve a tokamak with the goals of providing an ignited plasma for pulses of hundreds of seconds. A simple model is described in this memorandum which establishes the physics conditions for such a self-sustaining plasma, for given ion and electron thermal diffusivities, in terms of R/a, b/a, I, B/q, epsilon β/sub p/, anti T/sub i/, and anti T/sub e//anti T/sub i/. The model is used to produce plots showing the wide range of tokamaks that may ignite or have a given ignition margin. The constraints that limit this range are discussed

  17. Electron transport and shock ignition

    Energy Technology Data Exchange (ETDEWEB)

    Bell, A R; Tzoufras, M, E-mail: t.bell1@physics.ox.ac.uk [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)

    2011-04-15

    Inertial fusion energy (IFE) offers one possible route to commercial energy generation. In the proposed 'shock ignition' route to fusion, the target is compressed at a relatively low temperature and then ignited using high intensity laser irradiation which drives a strong converging shock into the centre of the fuel. With a series of idealized calculations we analyse the electron transport of energy into the target, which produces the pressure responsible for driving the shock. We show that transport in shock ignition lies near the boundary between ablative and heat front regimes. Moreover, simulations indicate that non-local effects are significant in the heat front regime and might lead to increased efficiency by driving the shock more effectively and reducing heat losses to the plasma corona.

  18. Tokamak power reactor ignition and time dependent fractional power operation

    International Nuclear Information System (INIS)

    Vold, E.L.; Mau, T.K.; Conn, R.W.

    1986-06-01

    A flexible time-dependent and zero-dimensional plasma burn code with radial profiles was developed and employed to study the fractional power operation and the thermal burn control options for an INTOR-sized tokamak reactor. The code includes alpha thermalization and a time-dependent transport loss which can be represented by any one of several currently popular scaling laws for energy confinement time. Ignition parameters were found to vary widely in density-temperature (n-T) space for the range of scaling laws examined. Critical ignition issues were found to include the extent of confinement time degradation by alpha heating, the ratio of ion to electron transport power loss, and effect of auxiliary heating on confinement. Feedback control of the auxiliary power and ion fuel sources are shown to provide thermal stability near the ignition curve

  19. An Auto-Tuning PI Control System for an Open-Circuit Low-Speed Wind Tunnel Designed for Greenhouse Technology

    Directory of Open Access Journals (Sweden)

    Karlos Espinoza

    2015-08-01

    Full Text Available Wind tunnels are a key experimental tool for the analysis of airflow parameters in many fields of application. Despite their great potential impact on agricultural research, few contributions have dealt with the development of automatic control systems for wind tunnels in the field of greenhouse technology. The objective of this paper is to present an automatic control system that provides precision and speed of measurement, as well as efficient data processing in low-speed wind tunnel experiments for greenhouse engineering applications. The system is based on an algorithm that identifies the system model and calculates the optimum PI controller. The validation of the system was performed on a cellulose evaporative cooling pad and on insect-proof screens to assess its response to perturbations. The control system provided an accuracy of <0.06 m·s‾1 for airflow speed and <0.50 Pa for pressure drop, thus permitting the reproducibility and standardization of the tests. The proposed control system also incorporates a fully-integrated software unit that manages the tests in terms of airflow speed and pressure drop set points.

  20. Compositional effects on the ignition of FACE gasolines

    KAUST Repository

    Sarathy, Mani; Kukkadapu, Goutham; Mehl, Marco; Javed, Tamour; Ahmed, Ahfaz; Naser, Nimal; Tekawade, Aniket; Kosiba, Graham; Alabbad, Mohammed; Singh, Eshan; Park, Sungwoo; Rashidi, Mariam Al; Chung, Suk-Ho; Roberts, William L.; Oehlschlaeger, Matthew A.; Sung, Chih-Jen; Farooq, Aamir

    2016-01-01

    kinetics linking fuel composition with ignition characteristics. A key discovery of this work is the kinetic coupling between aromatics and naphthenes, which affects the radical pool population and thereby controls ignition. © 2016 The Combustion Institute.

  1. Compositional effects on the ignition of FACE gasolines

    KAUST Repository

    Sarathy, Mani

    2016-05-08

    kinetics linking fuel composition with ignition characteristics. A key discovery of this work is the kinetic coupling between aromatics and naphthenes, which affects the radical pool population and thereby controls ignition. © 2016 The Combustion Institute.

  2. Flow Friction or Spontaneous Ignition?

    Science.gov (United States)

    Stoltzfus, Joel M.; Gallus, Timothy D.; Sparks, Kyle

    2012-01-01

    "Flow friction," a proposed ignition mechanism in oxygen systems, has proved elusive in attempts at experimental verification. In this paper, the literature regarding flow friction is reviewed and the experimental verification attempts are briefly discussed. Another ignition mechanism, a form of spontaneous combustion, is proposed as an explanation for at least some of the fire events that have been attributed to flow friction in the literature. In addition, the results of a failure analysis performed at NASA Johnson Space Center White Sands Test Facility are presented, and the observations indicate that spontaneous combustion was the most likely cause of the fire in this 2000 psig (14 MPa) oxygen-enriched system.

  3. PITR: Princeton Ignition Test Reactor

    International Nuclear Information System (INIS)

    1978-12-01

    The principal objectives of the PITR - Princeton Ignition Test Reactor - are to demonstrate the attainment of thermonuclear ignition in deuterium-tritium, and to develop optimal start-up techniques for plasma heating and current induction, in order to determine the most favorable means of reducing the size and cost of tokamak power reactors. This report describes the status of the plasma and engineering design features of the PITR. The PITR geometry is chosen to provide the highest MHD-stable values of beta in a D-shaped plasma, as well as ease of access for remote handling and neutral-beam injection

  4. Confinement of ignition and yield on the National Ignition Facility

    International Nuclear Information System (INIS)

    Tobin, M.; Karpenko, V.; Foley, D.; Anderson, A.; Burnham, A.; Reitz, T.; Latkowski, J.; Bernat, T.

    1996-01-01

    The National Ignition Facility Target Areas and Experimental Systems has reached mid-Title I design. Performance requirements for the Target Area are reviewed and design changes since the Conceptual Design Report are discussed. Development activities confirm a 5-m radius chamber and the viability of a boron carbide first wall. A scheme for cryogenic target integration with the NIF Target Area is presented

  5. Büroo Ignite = Ignite office / Priit Põldme, Reet Sepp

    Index Scriptorium Estoniae

    Põldme, Priit, 1971-

    2013-01-01

    Büroo Ignite (Tatari 25, Tallinn) sisekujundusest. Sisearhitektid Priit Põldme ja Reet Sepp (SAB Joonprojekt). Arhitektid Heiki Taras ja Ahti Luhaäär (Arhitektibüroo Pilter ja Taras). Sisearhitekti ja ESLi aastapreemiate žürii esimehe Kaido Kivi arvamus

  6. The national ignition facility: path to ignition in the laboratory

    International Nuclear Information System (INIS)

    Moses, E.I.; Bonanno, R.E.; Haynam, C.A.; Kauffman, R.L.; MacGowan, B.J.; Patterson Jr, R.W.; Sawicki, R.H.; Van Wonterghem, B.M.

    2007-01-01

    The National Ignition Facility (NIF) is a 192-beam laser facility presently under construction at Lawrence Livermore National Laboratory. When completed, NIF will be a 1.8-MJ, 500-TW ultraviolet laser system. Its missions are to obtain fusion ignition of deuterium-tritium plasmas in ICF (Inertial Confinement Fusion) targets and to perform high energy density experiments in support of the U.S. nuclear weapons stockpile. The NIF facility will consist of 2 laser bays, 4 capacitor areas, 2 laser switchyards, the target area and the building core. The laser is configured in 4 clusters of 48 beams, 2 in each laser bay. Four of the NIF beams have been already commissioned to demonstrate laser performance and to commission the target area including target and beam alignment and laser timing. During this time, NIF has demonstrated on a single-beam basis that it will meet its performance goals and has demonstrated its precision and flexibility for pulse shaping, pointing, timing and beam conditioning. It also performed 4 important experiments for ICF and High Energy Density Science. Presently, the project is installing production hardware to complete the project in 2009 with the goal to begin ignition experiments in 2010. An integrated plan has been developed including the NIF operations, user equipment such as diagnostics and cryogenic target capability, and experiments and calculations to meet this goal. This talk will provide NIF status, the plan to complete NIF, and the path to ignition. (authors)

  7. Surface breakdown igniter for mercury arc devices

    Science.gov (United States)

    Bayless, John R.

    1977-01-01

    Surface breakdown igniter comprises a semiconductor of medium resistivity which has the arc device cathode as one electrode and has an igniter anode electrode so that when voltage is applied between the electrodes a spark is generated when electrical breakdown occurs over the surface of the semiconductor. The geometry of the igniter anode and cathode electrodes causes the igniter discharge to be forced away from the semiconductor surface.

  8. Ignition and spread of electrical wire fires

    OpenAIRE

    Huang, Xinyan

    2012-01-01

    Ignition of electrical wires by external heating is investigated in order to gain a better understanding of the initiation of electrical-wire fires. An ignition-to- spread model is developed to systematically explain ignition and the following transition to spread. The model predicts that for a higher-conductance wire it is more difficult to achieve ignition and the weak flame may extinguish during the transition phase because of a large conductive heat loss along the wire core. Wires with tw...

  9. Structure ignition assessment model (SIAM)\\t

    Science.gov (United States)

    Jack D. Cohen

    1995-01-01

    Major wildland/urban interface fire losses, principally residences, continue to occur. Although the problem is not new, the specific mechanisms are not well known on how structures ignite in association with wildland fires. In response to the need for a better understanding of wildland/urban interface ignition mechanisms and a method of assessing the ignition risk,...

  10. 14 CFR 33.69 - Ignitions system.

    Science.gov (United States)

    2010-01-01

    ... STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.69 Ignitions system. Each..., except that only one igniter is required for fuel burning augmentation systems. [Amdt. 33-6, 39 FR 35466... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ignitions system. 33.69 Section 33.69...

  11. 基于环境因素与模糊识别的太阳自动跟踪控制策略%Solar auto-tracking control strategy based on environmental factors and fuzzy identification

    Institute of Scientific and Technical Information of China (English)

    王林军; 门静; 许立晓; 张东; 邓煜; 吕耀平; 陈艳娟

    2015-01-01

    . Considering that the disadvantages of solar energy are ever-changing solar radiation direction and unstable solar energy, dish solar thermal power generation uses an auto-tracking system to improve the utilization ratio of solar energy for an solar automatic tracking system can keep the incident sunlight parallel to the collector. A dish solar thermal power generation system works out of doors, environmental factors have a great influence on the system’s running stability and tracking accuracy, and affects the choice of tracking mode. The auto-tracking modes can be classified into:program tracking mode, photoelectric tracking mode, and hybrid tracking mode. Program tracking mode uses a computer to calculate the sun’s azimuth and latitude, can work under all-weather condition, and has high adaptability, but it has a cumulative error in the tracking process. The photoelectric mode has higher tracking accuracy for it has feedback information. It works well in the sunny day, but bad weather (especially the rainy and cloudy day) has a serious effect on it. A solar auto-tracking system usually adopts a hybrid tracking mode which is a combination of the program tracking mode and the photoelectric mode. A photoelectric sensor, as the information feedback component of a control system, can modify the cumulative error of the procedure, the tracking system would track reliably in the complicated and changeable weather. These two tracking modes make up for each other, as a result, the tracking system’s precision and stability would be further improved and guaranteed. As an auto-tracking system works, the tracking mode changes as the intensity value reaches the intensity threshold, then the controller will choose a tracking mode automatically. Considering that the environmental factors affect the tracking system, this paper mainly analyses intensity, intensity change, and wind speed which have a serious effect on the system’s operational stability and tracking accuracy. It uses

  12. 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.

  13. Plasma ignition of LOVA propellants

    NARCIS (Netherlands)

    Driel, C.A. van; Boluijt, A.G.; Schilt, A.

    2010-01-01

    Ignition experiments were performed using a gun simulator which is equipped with a burst disk. This equipment facilitates the application of propellant loading densities which are comparable to those applied in regular ammunitions. For this study the gun simulator was equipped with a plasma jet

  14. AC ignition of HID lamps

    NARCIS (Netherlands)

    Sobota, A.; Kanters, J.H.M.; Manders, F.; Veldhuizen, van E.M.; Haverlag, M.

    2010-01-01

    Our aim was to examine the starting behaviour of mid-pressure argon discharges in pin-pin (point-to-point) geometry, typically used in HID lamps. We focused our work on AC ignition of 300 and 700 mbar Ar discharges in Philips 70W standard burners. Frequency was varied between 200 kHz and 1 MHz. In

  15. Discharge ignition near a dielectric

    NARCIS (Netherlands)

    Sobota, A.; Veldhuizen, van E.M.; Stoffels, W.W.

    2008-01-01

    Electrical breakdown in noble gas near a dielectric is an important issue in lighting industry. In order to investigate the influence of the dielectric on the ignition process, we perform measurements in argon, with pressure varying from 0.1 to 1 bar, using a pin–pin electrode geometry. Here, we

  16. Tank farm potential ignition sources

    International Nuclear Information System (INIS)

    Scaief, C.C. III.

    1996-01-01

    This document identifies equipment, instrumentation, and sensors that are located in-tank as well as ex-tank in areas that may have communication paths with the tank vapor space. For each item, and attempt is made to identify the potential for ignition of flammable vapors using a graded approach. The scope includes all 177 underground storage tanks

  17. AutoCAD 2015 and AutoCAD LT 2015 bible

    CERN Document Server

    Finkelstein, Ellen

    2014-01-01

    The perfect reference for all AutoCAD users AutoCAD 2015 and AutoCAD LT 2015 Bible is the book you want to have close at hand to answer those day-to-day questions about this industry-leading software. Author and Autodesk University instructor Ellen Finkelstein guides readers through AutoCAD 2015 and AutoCAD LT 2015 with clear, easy-to-understand instruction and hands-on tutorials that allow even total beginners to create a design on their very first day. Although simple and fundamental enough to be used by those new to CAD, the book is so comprehensive that even Autodesk power u

  18. Auto-immune Haemolytic Anaemia and Paroxys

    African Journals Online (AJOL)

    who presented with an acute auto-immune haemolytic anaemia. In addition to a persistently positive Coombs test, with specific red cell auto-antibodies, the acidified serum test and the sucrose haemolysis test were repeatedly positive. CASE REPORT. A 24-year-old Indian woman was admitted to hospital in. July 1969.

  19. Fonctionnement transitoire et controle de la richesse des moteurs à allumage commandé à injection multipoint Transient Operation and Air-Fuel Ratio Control of Spark-Ignition Port-Injected Engines

    Directory of Open Access Journals (Sweden)

    Le Moyne L.

    2006-12-01

    Full Text Available Sur les moteurs à allumage commandé à injection multipoint on observe des désadaptations de richesse lors de fonctionnement transitoire. Ces désadaptations sont dues au dépôt, sous forme de film liquide, du carburant injecté dans le collecteur. Elles peuvent être compensées par une gestion adéquate de la masse injectée. Ainsi, afin d'obtenir la masse de carburant qui maintient la richesse constante, nous avons développé un modèle bidimensionnel des écoulements dans le collecteur au cours du cycle moteur. Ce modèle décrit l'écoulement des gaz frais, des gouttes injectées, des gaz brûlés refoulés vers l'admission et du film sur les parois, sur le principe de la séparation des phases. Nous montrons que le modèle reproduit correctement le signal de richesse et comment il permet de supprimer les désadaptations. La mesure de richesse est faite à l'échappement avec une sonde à oxygène dont nous validons le fonctionnement en transitoire avec une corrélation à la pression maximale du cycle dans le cylindre. Air-fuel ratio excursions are observed on port-injected spark ignition engines during transients. This excursions result from the liquid fuel film deposited on intake port. They can be compensated by controlling the injected fuel mass. In order to have the amount of fuel that keeps air-fuel ratio constant, we have developed a 2D model of flows in the intake port during engine cycle. This separate phases model describes the flow of fresh gases, injected droplets, hot burned gases and film on port walls. We show that the model effectively predicts the equivalence ratio and how it allows to eliminate excursions. Equivalence ratio measures are made with an oxygen sensor which functioning is validated during transients by correlating it to maximal pressure during engine cycle.

  20. Photothermally activated motion and ignition using aluminum nanoparticles

    International Nuclear Information System (INIS)

    Abboud, Jacques E.; Chong Xinyuan; Zhang Mingjun; Zhang Zhili; Jiang Naibo; Roy, Sukesh; Gord, James R.

    2013-01-01

    The aluminum nanoparticles (Al NPs) are demonstrated to serve as active photothermal media, to enhance and control local photothermal energy deposition via the photothermal effect activated by localized surface plasmon resonance (LSPR) and amplified by Al NPs oxidation. The activation source is a 2-AA-battery-powered xenon flash lamp. The extent of the photothermally activated movement of Al NPs can be ∼6 mm. Ignition delay can be ∼0.1 ms. Both scanning electron microscopy and energy-dispersive X-ray spectroscopy measurements of motion-only and after-ignition products confirm significant Al oxidation occurs through sintering and bursting after the flash exposure. Simulations suggest local heat generation is enhanced by LSPR. The positive-feedback effects from the local heat generation amplified by Al oxidation produce a large increase in local temperature and pressure, which enhances movement and accelerates ignition.

  1. Desensitizing nano powders to electrostatic discharge ignition

    International Nuclear Information System (INIS)

    Steelman, Ryan; Daniels, Michael A.

    2015-01-01

    Electrostatic discharge (ESD) is a main cause for ignition in powder media ranging from grain silos to fireworks. Nanoscale particles are orders of magnitude more ESD ignition sensitive than their micron scale counterparts. This study shows that at least 13 vol. % carbon nanotubes (CNT) added to nano-aluminum and nano-copper oxide particles (nAl + CuO) eliminates ESD ignition sensitivity. The CNT act as a conduit for electric energy and directs electric charge through the powder to desensitize the reactive mixture to ignition. For nanoparticles, the required CNT concentration for desensitizing ESD ignition acts as a diluent to quench energy propagation.

  2. Auto-immune hepatitis following delivery.

    Science.gov (United States)

    Saini, Vandana; Gupta, Mamta; Mishra, S K

    2013-05-01

    Auto-immune hepatitis first presenting in the early postpartum period is rare. Immunosuppressive effects of pregnancy result in delayed manifestation of auto-immune hepatitis, and in established cases, the spontaneous improvements are there. Auto-immune hepatitis should be considered in the differential diagnosis of liver dysfunction first presenting in the early postpartum period. A case of postpartum hepatitis of auto-immune aetiology is being presented here. It is disease of unknown aetiology, characterised by inflammation of liver (as evidenced by raised serum transaminases, presence of interface hepatitis on histological examination), hypergammaglobulinaemia (> 1.5 times normal), presence of auto-antibodies [(antinuclear antibodies (ANA)], smooth muscle antibody (SMA) and antibody to liver-kidney microsome type 1 (LKM1) in the absence of viral markers ie, hepatitis B (HBsAg) and C (AntiHCV) and excellent response to corticosteroid therapy.

  3. AutoCAD 2008 and AutoCAD LT 2008 Bible

    CERN Document Server

    Finkelstein, Ellen

    2011-01-01

    "Whether you're new to AutoCAD or a veteran, you will undoubtedly find this book to be an excellent resource."-- Abhi Singh, AutoCAD Product Manager, Autodesk, Inc.Here's the book that makes AutoCAD approachableEven the people at Autodesk look to Ellen Finkelstein for AutoCAD training, so who better to teach you about AutoCAD 2008? This comprehensive guide brings veterans up to speed on AutoCAD updates and takes novices from the basics to programming in AutoLISP(r) and VBA. Every feature is covered in a logical order, and with the Quick Start chapter, you'll be creating drawings on your very f

  4. Application of Alcohols to Dual - Fuel Feeding the Spark-Ignition and Self-Ignition Engines

    Directory of Open Access Journals (Sweden)

    Stelmasiak Zdzisław

    2014-10-01

    Full Text Available 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 the tests on spark- ignition and self- ignition engines fed with two fuels: petrol and methanol or diesel oil and methanol, respectively. Te tests were carried out on a 1100 MPI Fiat four- cylinder engine with multi-point injection and a prototype collector fitted with additional injectors in each cylinder. Te other tested engine was a SW 680 six- cylinder direct- injection diesel engine. Influence of a methanol addition on basic operational parameters of the engines and exhaust gas toxicity were analyzed. Te tests showed a favourable influence of methanol on combustion process of traditional fuels and on some operational parameters of engines. An addition of methanol resulted in a distinct rise of total efficiency of both types of engines at maintained output parameters (maximum power and torque. In the same time a radical drop in content of hydrocarbons and nitrogen oxides in exhaust gas was observed at high shares of methanol in feeding dose of ZI (petrol engine, and 2-3 fold lower smokiness in case of ZS (diesel engine. Among unfavourable phenomena, a rather insignificant rise of CO and NOx content for ZI engine, and THC and NOx - for ZS engine, should be numbered. It requires to carry out further research on optimum control parameters of the engines. Conclusions drawn from this work may be used for implementation of bio-fuels to feeding the combustion engines.

  5. Physical studies of fast ignition in China

    International Nuclear Information System (INIS)

    He, X T; Cai, Hong-bo; Wu, Si-zhong; Cao, Li-hua; Zhang, Hua; He, Ming-qing; Chen, Mo; Wu, Jun-feng; Zhou, Cang-tao; Zhou, Wei-Min; Shan, Lian-qiang; Wang, Wei-wu; Zhang, Feng; Bi, Bi; Zhao, Zong-qing; Gu, Yu-qiu; Zhang, Bao-han; Wang, Wei; Fang, Zhi-heng; Lei, An-le

    2015-01-01

    Fast ignition approach to inertial confinement fusion is one of the important goals today, in addition to central hot spot ignition in China. The SG-IIU and PW laser facilities are coupled to investigate the hot spot formation for fast ignition. The SG-III laser facility is almost completed and will be coupled with tens kJ PW lasers for the demonstration of fast ignition. In recent years, for physical studies of fast ignition, we have been focusing on the experimental study of implosion symmetry, M-band radiation preheating and mixing, advanced fast ignition target design, and so on. In addition, the modeling capabilities and code developments enhanced our ability to perform the hydro-simulation of the compression implosion, and the particle-in-cell (PIC) and hybrid-PIC simulation of the generation, transport and deposition of relativistic electron beams. Considerable progress has been achieved in understanding the critical issues of fast ignition. (paper)

  6. Ignitability of hydrogen/oxygen/diluent mixtures in the presence of hot surfaces

    International Nuclear Information System (INIS)

    Kumar, R.K.; Koroll, G.W.

    1995-01-01

    In the licensing process for CANDU nuclear power stations it is necessary to demonstrate tolerance to a wide range of low-probability accidents. These include loss of moderator accidents that may lead to the formation of flammable mixtures of deuterium, oxygen, helium, and steam in the reactor calandria vessel. Uncovered adjuster or control rods are considered as possible sources of ignition when a flammable mixture is present. A knowledge of the minimum hot-surface temperature required for ignition is important in assessing the reactor safety. These hot surface temperatures were measured using electrically heated adjuster rod simulators in a large spherical vessel (2.3-m internal diameter). Whereas the effects of geometry on ignition temperature were studied in the large-scale apparatus, some of the effects, such as those produced by a strong radiation field, were studied using a small-scale apparatus. Investigations carried our over a range of hydrogen and diluent concentrations indicated that, although the ignition temperatures were fairly insensitive to the hydrogen concentration, they were strongly affected by the presence of steam The addition of 30% steam to a dry combustible mixture increased the minimum surface temperature required for ignition by approximates 100 degrees C of the diluents investigated, steam had the most effect on ignition. The effect of initial temperature of the mixture on the ignition temperature was small, whereas the effect of initial pressure was significant. The effect of substituting deuterium for hydrogen on ignition temperature was small. The effect of a high-intensity gamma-radiation field on the minimum hot-surface temperature required for ignition was investigated using a 2-dm 3 ignition vessel placed in a linear accelerator. Radiation had no measurable effect on ignition temperature

  7. SYNTHESIS OF AUTOMOBILE IGNITION SYSTEM USING OZONIZED FUEL

    Directory of Open Access Journals (Sweden)

    O. M. Pilipenko

    2015-01-01

    Full Text Available The paper presents a mathematical model for electronic control system of the angular ignition timing (AIT in the (ICE, which is running on ozonized fuel. An algorithm for  ignition system control of internal combustion engine using ozonized fuel has been developed in the paper. A structure of the dynamic ignition system while using a control unit for supplying  ozone into fuel with a purpose to improve automobile ecological and economical indices adapted to operational conditions. Application of the given system allows to ensure minimum reduction of operational petrol consumption and concentration of incomplete combustion products due to optimum ozone dosage into the fuel.  The paper proposes a controlled automobile ignition system as a sequential scheme which has a great number of discrete inputs and outputs and many discrete internal  states. The scheme establishes a functional dependence between input and output states. The paper provides an assessment of ecological indices according to massive emissions of carbon monoxide СО, hydrocarbon СпНт and nitric oxide NOx .  The analysis of  investigations results has been carried out in the paper.

  8. Development and evaluation of a self-cleaning custom-built auto sampler controlled by a low-cost RaspberryPi microcomputer for online enzymatic activity measurements.

    Science.gov (United States)

    Stadler, Philipp; Farnleitner, Andreas H; Zessner, Matthias

    2017-01-01

    A fully automated on-site device (SAMP-FIL) that enables water sampling with simultaneous filtration and effective cleaning procedures of the device's components was developed and field-tested. The SAMP-FIL was custom-built using commercially available components and was controlled by a RaspberryPi single-board computer operating open-source software. SAMP-FIL was designed for sample pre-treatment with minimal sample alteration to meet the requirements of on-site measurement devices that cannot handle coarse suspended solids within the measurement procedure or cycle. A highly effective cleaning procedure provides a fresh and minimally altered sample for the connected measurement device. The construction and programmed software facilitates the use of SAMP-FIL for different connected measurement devices. The SAMP-FIL sample pretreatment was tested for over one year for rapid and on-site enzymatic activity (beta-d-glucuronidase, GLUC) determination (BACTcontrol) in sediment-laden stream water. The formerly used proprietary sampling set-up was assumed to lead to significant damping of the measurement signal due to its susceptibility to clogging, debris accumulation and bio-film accumulation. The implementation of SAMP-FIL considerably increased the error-free running time and measurement accuracy of BACTcontrol devices. This paper describes how low-cost microcomputers, such as the RaspberryPi, can be used by operators to substantially improve established measuring systems via effective sampling devices. Furthermore, the results of this study highlight the importance of adequate sample pretreatment for the quality of on-site measurements. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  9. Polarization Imaging Apparatus with Auto-Calibration

    Science.gov (United States)

    Zou, Yingyin Kevin (Inventor); Zhao, Hongzhi (Inventor); Chen, Qiushui (Inventor)

    2013-01-01

    A polarization imaging apparatus measures the Stokes image of a sample. The apparatus consists of an optical lens set, a first variable phase retarder (VPR) with its optical axis aligned 22.5 deg, a second variable phase retarder with its optical axis aligned 45 deg, a linear polarizer, a imaging sensor for sensing the intensity images of the sample, a controller and a computer. Two variable phase retarders were controlled independently by a computer through a controller unit which generates a sequential of voltages to control the phase retardations of the first and second variable phase retarders. A auto-calibration procedure was incorporated into the polarization imaging apparatus to correct the misalignment of first and second VPRs, as well as the half-wave voltage of the VPRs. A set of four intensity images, I(sub 0), I(sub 1), I(sub 2) and I(sub 3) of the sample were captured by imaging sensor when the phase retardations of VPRs were set at (0,0), (pi,0), (pi,pi) and (pi/2,pi), respectively. Then four Stokes components of a Stokes image, S(sub 0), S(sub 1), S(sub 2) and S(sub 3) were calculated using the four intensity images.

  10. A polar-drive shock-ignition design for the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, K. S.; McKenty, P. W.; Collins, T. J. B.; Craxton, R. S.; Delettrez, J. A.; Marozas, J. A.; Skupsky, S.; Shvydky, A. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623 (United States); Betti, R. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623 (United States); Fusion Science Center, University of Rochester, Rochester, New York 14623 (United States); Departments of Mechanical Engineering and Physics, University of Rochester, Rochester, New York 14627 (United States); Hohenberger, M.; Theobald, W.; Lafon, M.; Nora, R. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623 (United States); Fusion Science Center, University of Rochester, Rochester, New York 14623 (United States)

    2013-05-15

    Shock ignition [R. Betti et al., Phys. Rev. Lett. 98, 155001 (2007)] is being pursued as a viable option to achieve ignition on the National Ignition Facility (NIF). Shock-ignition target designs use a high-intensity laser spike at the end of a low-adiabat assembly pulse to launch a spherically convergent strong shock to ignite the hot spot of an imploding capsule. A shock-ignition target design for the NIF is presented. One-dimensional simulations indicate an ignition threshold factor of 4.1 with a gain of 58. A polar-drive beam-pointing configuration for shock-ignition experiments on the NIF at 750 kJ is proposed. The capsule design is shown to be robust to the various one- and two-dimensional effects and nonuniformities anticipated on the NIF. The target is predicted to ignite with a gain of 38 when including all anticipated levels of nonuniformity and system uncertainty.

  11. Fast ignition studies at Osaka University

    International Nuclear Information System (INIS)

    Tanaka, K. A.

    2007-01-01

    After the invention of the chirped pulse amplification technique [1], the extreme conditions of matters have become available in laboratory spaces and can be studied with the use of ultra intense laser pulse (UILP) with a high energy. One such example is the fast ignition [2] where UILP is used to heat a highly compressed fusion fuel core within 1-10 pico-seconds before the core disassembles. It is predicted possible with use of 50-100 kJ lasers for both imploding the fuel and heating [2] to attain a large fusion gain. Fast ignition was shown to be a promising new scheme for laser fusion [3] with a PW (= 10 1 5 W) UILP and GEKKO XII laser systems at Osaka. Many new physics have been found with use of UILP in a relativistic parameter regime during the process of the fast ignition studies. UILP can penetrate into over-dense plasma for a couple hundred microns distance with a self-focusing and relativistic transparency effects. Hot electrons of 1-100 MeV can be easily created and are under studies for its spectral and emission angle controls. Strong magnetic fields of 10's of MGauss are created to guide these hot electrons along the target surface [4]. Based on these results, a new and largest UILP laser machine of 10 kJ energy at PW UILP peak power is under construction to test if we can achieve the sub-ignition fusion condition at Osaka University. The machine requires challenging optical technologies such as large size (0.9 m) gratings, tiling these gratings for UILP compression; segmenting four large UILP beams to obtain diffraction limited focal spot. We would like to over-view all of these activities. References [1]D. STRICKLAND and G. MOUROU, Opt. Commun., 56, 219 (1985) [2] S. ATZENI et al., Phys Plasmas, 6, 3316 (1999) [3] R. KODAMA, K.A. TANAKA et al., Nature, 418, 933 (2002) [4] A.L. LEI, K.A. TANAKA et al., Phys. Rev. Lett., 96, 255006(2006) ; H. HABARA, K.A. TANAKA et al., Phys. Rev. Lett., 97, 095004 (2006)

  12. Shock ignition targets: gain and robustness vs ignition threshold factor

    Science.gov (United States)

    Atzeni, Stefano; Antonelli, Luca; Schiavi, Angelo; Picone, Silvia; Volponi, Gian Marco; Marocchino, Alberto

    2017-10-01

    Shock ignition is a laser direct-drive inertial confinement fusion scheme, in which the stages of compression and hot spot formation are partly separated. The hot spot is created at the end of the implosion by a converging shock driven by a final ``spike'' of the laser pulse. Several shock-ignition target concepts have been proposed and relevant gain curves computed (see, e.g.). Here, we consider both pure-DT targets and more facility-relevant targets with plastic ablator. The investigation is conducted with 1D and 2D hydrodynamic simulations. We determine ignition threshold factors ITF's (and their dependence on laser pulse parameters) by means of 1D simulations. 2D simulations indicate that robustness to long-scale perturbations increases with ITF. Gain curves (gain vs laser energy), for different ITF's, are generated using 1D simulations. Work partially supported by Sapienza Project C26A15YTMA, Sapienza 2016 (n. 257584), Eurofusion Project AWP17-ENR-IFE-CEA-01.

  13. Self-organized ignition of a tokamak plasma

    International Nuclear Information System (INIS)

    Schoepf, K.

    2007-01-01

    The continuous progress in the attainment of plasma parameters required for establishing nuclear fusion in magnetically confined plasmas as well as the prospect of feasible steady-state operation has instigated the interest in the physics of burning plasmas [1]. Aside from the required plasma current drive, fusion energy production with tokamaks demands particular attention to confinement and fuelling regimes in order to maintain the plasma density n and temperature T at favourable values matching with specific requirements such as the triple product nτ E T, where τ E represents the plasma energy confinement time. The identification of state and parameter space regions capable of ignited fusion plasma operation is evidently crucial if significant energy gains are to be realized over longer periods. Examining the time-evolving state of tokamak fusion plasma in a parameter space spanned by the densities of plasma constituents and their temperatures has led to the formation of an ignition criterion [2] fundamentally different from the commonly used static patterns. The incorporation of non-stationary particle and energy balances into the analysis here, the application of a 'soft' Troyon beta limit [3], the consideration of actual fusion power deposition [4,5] and its effect of reducing τ E are seen to significantly influence the fusion burn dynamics and to shape the ignition conditions. The presented investigation refers to a somewhat upgraded (to achieve ignition) ITER-like tokamak plasma and uses volume averages of locally varying quantities and processes. The resulting ignition criterion accounts for the dynamic evolution of a reacting plasma controlled by heating and fuel feeding. Interestingly, also self-organized ignition can be observed: a fusion plasma possessing a density and temperature above a distinct separatrix in the considered parameter phase space is seen to evolve - without external heating and hence practically by itself - towards an ignited

  14. Effect of Timing and Location of Hotspot on Super Knock during Pre-ignition

    KAUST Repository

    Jaasim, Mohammed

    2017-03-28

    Pre-ignition in SI engine is a critical issue that needs addressing as it may lead to super knock event. It is widely accepted that pre-ignition event emanates from hot spot(s) that can be anywhere inside the combustion chamber. The location and timing of hotspot is expected to influence the knock intensity from a pre-ignition event. In this study, we study the effect of location and timing of hot spot inside the combustion chamber using numerical simulations. The simulation is performed using a three-dimensional computational fluid dynamics (CFD) code, CONVERGE™. We simulate 3-D engine geometry coupled with chemistry, turbulence and moving structures (valves, piston). G-equation model for flame tracking coupled with multi-zone model is utilized to capture auto-ignition (knock) and solve gas phase kinetics. A parametric study on the effect of hot spot timing and location inside the combustion chamber is performed. The hot spot timing considered are -180 CAD, -90 CAD and -30 CAD and the locations of the hot spots are in the center and two edges of the piston surfaces. Simulation results for normal combustion cycle are validated against the experimental data. The simulation results show great sensitivity to the hot spot timing, and the influence of local temperature gradient is noted to be significant. In case of early hot spot timing of -180 CAD, the pre-ignition event did not lead to super knock. Nevertheless, at late hot spot timing, super knock was realized. On the other hand, the effect of hot spot location on pre-ignition event depends on the geometry of the combustion chamber.

  15. Gasoline auto ignition with diesel pilot injection; Ottomotorische Selbstzuendung mit Dieselpiloteinspritzung

    Energy Technology Data Exchange (ETDEWEB)

    Eichmeier, Johannes; Bach, Florian; Wagner, Uwe [Karlsruher Institut fuer Technologie (KIT), Karlsruhe (Germany). Inst. fuer Kolbenmaschinen; Sauer, Christina [MTU Friedrichshafen GmbH, Friedrichshafen (Germany). Team Brennverfahrensentwicklung Gasmotoren

    2013-04-15

    Against the background of climate change and ever-rising commodity prices, the simultaneous reduction of fuel consumption and exhaust emissions is the focus of modern research and development work in the field of internal combustion engines. In this context homogeneous Low-Temperature Combustion (LTC) is regarded as one of the most promising concepts to overcome the conflict of goals between high efficiencies and low emissions. In collaboration with MTU Friedrichshafen a new LTC combustion system which is characterised by least emissions, reasonable low fuel consumption and acceptable mechanical engine stress has been developed at the Institut fuer Kolbenmaschinen of the Karlsruhe Institute of Technology. (orig.)

  16. A Photographic Study of Combustion and Knock in a Spark-Ignition Engine

    Science.gov (United States)

    Rothrock, A M; Spencer, R C

    1938-01-01

    Report presents the results of a photographic study of the combustion in a spark-ignition engine using both Schlieren and flame photographs taken at high rates of speed. Although shock waves are present after knock occurs, there was no evidence of any type of sonic or supersonic compression waves existing in the combustion gases prior to the occurrence of knock. Artificially induced shock waves in the engine did not in themselves cause knock. The photographs also indicate that, although auto-ignition ahead of the flame front may occur in conjunction with knock, it is not necessary for the occurrence of knock. There is also evidence that the reaction is not completed in the flame front but continues for some time after the flame front has passed through the charge.

  17. Processos de auto-regulação no curso de vida: controle primário e controle secundário Self-regulation processes in the life-course: primary and secondary control

    Directory of Open Access Journals (Sweden)

    Hilma Tereza Tôrres Khoury

    2009-01-01

    Full Text Available Este artigo discute conceitos relevantes à perspectiva do curso de vida, porém pouco difundidos no Brasil: controle primário e controle secundário. O primeiro se refere aos esforços que o indivíduo empreende para adaptar o ambiente às suas necessidades; o segundo, para se adaptar ao ambiente. Apresenta-se a formulação original dos conceitos como modelo de dois processos de controle, em oposição a modelos de processo único, como o do desamparo aprendido. Em seguida, discute-se revisão conceitual que trouxe modificação e ampliação para estes construtos, concebendo-os em um modelo bidimensional que articula controle primário e secundário com os conceitos de seleção e compensação. Nesse processo, apresentam-se contribuições no intuito de estimular a reflexão e expandir a discussão teórico-conceitual que envolve estes construtos.This article discusses relevant concepts of life course perspective which are not very much diffused in Brazil: primary and secondary control. The former refers to efforts to change the environment so that it fits individual's needs. The latter involves efforts to fit in with the environment. The original definitions are presented as a two-process model of control in contrast to one-process models such as learned helplessness. Furthermore, it discusses a conceptual revision, which modified and expanded these constructs as a bi-dimensional model that relates primary and secondary control to the concepts of selection and compensation. In process of arguing about those, suggestions are presented for thinking and expanding the theoretical and conceptual discussion of these constructs.

  18. Forced Ignition Study Based On Wavelet Method

    Science.gov (United States)

    Martelli, E.; Valorani, M.; Paolucci, S.; Zikoski, Z.

    2011-05-01

    The control of ignition in a rocket engine is a critical problem for combustion chamber design. Therefore it is essential to fully understand the mechanism of ignition during its earliest stages. In this paper the characteristics of flame kernel formation and initial propagation in a hydrogen-argon-oxygen mixing layer are studied using 2D direct numerical simulations with detailed chemistry and transport properties. The flame kernel is initiated by adding an energy deposition source term in the energy equation. The effect of unsteady strain rate is studied by imposing a 2D turbulence velocity field, which is initialized by means of a synthetic field. An adaptive wavelet method, based on interpolating wavelets is used in this study to solve the compressible reactive Navier- Stokes equations. This method provides an alternative means to refine the computational grid points according to local demands of the physical solution. The present simulations show that in the very early instants the kernel perturbed by the turbulent field is characterized by an increased burning area and a slightly increased rad- ical formation. In addition, the calculations show that the wavelet technique yields a significant reduction in the number of degrees of freedom necessary to achieve a pre- scribed solution accuracy.

  19. The Ignition Physics Study Group

    International Nuclear Information System (INIS)

    Sheffield, J.

    1987-01-01

    In the US magnetic fusion program there have been relatively few standing committees of experts, with the mandate to review a particular sub-area on a continuing basis. Generally, ad hoc committees of experts have been assembled to advise on a particular issue. There has been a lack of broad, systematic and continuing review and analysis, combining the wisdom of experts in the field, in support of decision making. The Ignition Physics Study Group (IPSG) provides one forum for the systematic discussion of fusion science, complementing the other exchanges of information, and providing a most important continuity in this critical area. In a similar manner to the European program, this continuity of discussion and the focus provided by a national effort, Compact Ignition Tokamak (CIT), and international effort, Engineering Test Reactor (ETR), are helping to lower those barriers which previously were an impediment to rational debate

  20. Operation of neat pine oil biofuel in a diesel engine by providing ignition assistance

    International Nuclear Information System (INIS)

    Vallinayagam, R.; Vedharaj, S.; Yang, W.M.; Lee, P.S.

    2014-01-01

    Highlights: • Operational feasibility of neat pine oil biofuel has been examined. • Pine oil suffers lower cetane number, which mandates for necessary ignition assistance. • Ignition support is provided by preheating the inlet air and incorporating a glow plug. • At an inlet air temperature of 60 °C, the BTE for pine oil was found to be in par with diesel. • CO and smoke emissions were reduced by 13.2% and 16.8%, respectively, for neat pine oil. - Abstract: The notion to provide ignition support for the effective operation of lower cetane fuels in a diesel engine has been ably adopted in the present study for the sole fuel operation of pine oil biofuel. Having noted that the lower cetane number and higher self-ignition temperature of pine oil biofuel would inhibit its direct use in a diesel engine, combined ignition support in the form of preheating the inlet air and installing a glow plug in the cylinder head has been provided to improve the auto-ignition of pine oil. While, an air preheater, installed in the inlet manifold of the engine, preheated the inlet air so as to provide ignition assistance partially, the incorporation of glow plug in the cylinder head imparted the further required ignition support appropriately. Subsequently, the operational feasibility of neat pine oil biofuel has been examined in a single cylinder diesel engine and the engine test results were analyzed. From the experimental investigation, though the engine performance and emissions such as CO (carbon monoxide) and smoke were noted to be better for pine oil with an inlet air temperature of 40 °C, the engine suffered the setback of knocking due to delayed SOC (start of combustion). However, with the ignition support through glow plug and preheating of inlet air, the engine knocking was prevented and the normal operation of the engine was ensured. Categorically, at an inlet air temperature of 60 °C, BTE (brake thermal efficiency) was found to be in par with diesel, while

  1. Evaporation and Ignition Characteristics of Water Emulsified Diesel under Conventional and Low Temperature Combustion Conditions

    Directory of Open Access Journals (Sweden)

    Zhaowen Wang

    2017-07-01

    Full Text Available The combination of emulsified diesel and low temperature combustion (LTC technology has great potential in reducing engine emissions. A visualization study on the spray and combustion characteristics of water emulsified diesel was conducted experimentally in a constant volume chamber under conventional and LTC conditions. The effects of ambient temperature on the evaporation, ignition and combustion characteristics of water emulsified diesel were studied under cold, evaporating and combustion conditions. Experimental results showed that the ambient temperature had little effect on the spray structures, in terms of the liquid core length, the spray shape and the spray area. However, higher ambient temperature slightly reduced the Sauter Mean Diameter (SMD of the spray droplets. The auto-ignition delay time increased significantly with the decrease of the ambient temperature. The ignition process always occurred at the entrainment region near the front periphery of the liquid core. This entrainment region was evolved from the early injected fuel droplets which were heated and mixed by the continuous entrainment until the local temperature and equivalence ratio reached the ignition condition. The maximum value of integrated natural flame luminosity (INFL reduced by 60% when the ambient temperature dropped from 1000 to 800 K, indicating a significant decrease of the soot emissions could be achieved by LTC combustion mode than the conventional diesel engines.

  2. Second auto-SCT for treatment of relapsed multiple myeloma.

    Science.gov (United States)

    Gonsalves, W I; Gertz, M A; Lacy, M Q; Dispenzieri, A; Hayman, S R; Buadi, F K; Dingli, D; Hogan, W J; Kumar, S K

    2013-04-01

    High-dose therapy and auto-SCT remain integral in the initial treatment of multiple myeloma (MM), and are increasingly being applied for management of relapsed disease. We examined the outcomes in 98 patients undergoing salvage auto-SCT (auto-SCT2) for relapsed MM after receiving an initial transplant (auto-SCT1) between 1994 and 2009. The median age at auto-SCT2 was 60 years (range: 35-74). The median time between auto-SCT1 and auto-SCT2 was 46 months (range: 10-130). Treatment-related mortality was seen in 4%. The median PFS from auto-SCT2 was 10.3 (95% confidence interval (CI): 7-14) months and the median OS from auto-SCT2 was 33 months (95% CI: 28-51). In a multivariable analysis, shorter time to progression (TTP) after auto-SCT1, not achieving a CR after auto-SCT2, higher number of treatment regimens before auto-SCT2 and a higher plasma cell labeling index at auto-SCT2 predicted for shorter PFS. However, only a shorter TTP after auto-SCT1 predicted for a shorter OS post auto-SCT2. Hence, auto-SCT2 is an effective and feasible therapeutic option for MM patients relapsing after other treatments, especially in patients who had a TTP of at least 12 months after their auto-SCT1.

  3. Self-regulation processes in the life-course: primary and secondary control / Processos de auto-regulação no curso de vida: controle primário e controle secundário

    Directory of Open Access Journals (Sweden)

    Hilma Tereza Tôrres Khoury

    2009-01-01

    Full Text Available This article discusses relevant concepts of life course perspective which are not very much diffused in Brazil: primary and secondary control. The former refers to efforts to change the environment so that it fits individual's needs. The latter involves efforts to fit in with the environment. The original definitions are presented as a two-process model of control in contrast to one-process models such as learned helplessness. Furthermore, it discusses a conceptual revision, which modified and expanded these constructs as a bi-dimensional model that relates primary and secondary control to the concepts of selection and compensation. In process of arguing about those, suggestions are presented for thinking and expanding the theoretical and conceptual discussion of these constructs.

  4. Low current approach to ignition

    International Nuclear Information System (INIS)

    Cenacchi, G.; Sugiyama, L.; Airoldi, A.; Coppi, B.

    1996-01-01

    The open-quotes standardclose quotes path to achieve ignition conditions so far has been that of producing plasmas with the maximum current and poloidal field that axe compatible with the applied toroidal field and the geometry of the adopted configuration (the low q a approach.) The other approach is that motivated by recent experiments with reversed shear configurations, with relatively low currents and high fields corresponding to high values of q a (e-g., q a ≅ 6). While the first approach can be pursued with ohmic heating alone, the second one necessarily involves an auxiliary heating system. One of the advantages of this approach is that the onset of large scale internal modes can be avoided as q(ψ) is kept above 1 over the entire plasma column. Since quite peaked density profiles are produced in the regimes where enhanced confinement is observed, the α-particle power levels for which ignition can be reached and therefore the thermal wall loading on the first wall, can be reduced relatively to the standard, low q a , approach. The possibility is considered that ignition is reached in the reversed shear, high q a , regime and that this is followed by a transition to non-reversed profiles, or even the low q a regime, assuming that the excitation of modes involving magnetic reconnection will not undermine the needed degree of confinement. These results have been demonstrated by numerical transport simulation for the Ignitor-Ult machine, but are applicable to all high field ignition experiments

  5. Assessing the prospects for achieving double-shell ignition on the National Ignition Facility using vacuum hohlraums

    Science.gov (United States)

    Amendt, Peter

    2006-10-01

    The goal of demonstrating ignition on the National Ignition Facility (NIF) has motivated a revisit of double-shell (DS) [1] targets as a complementary path to the baseline cryogenic single-shell approach [2]. Benefits of DS targets include room-temperature deuterium-tritium (DT) fuel preparation, minimal hohlraum-plasma-mediated laser backscatter, low threshold-ignition temperatures (4 keV) for relaxed hohlraum x-ray flux asymmetry tolerances [3], and loose shock timing requirements. On the other hand, DS ignition presents several challenges, including room-temperature containment of high-pressure DT (790 atm) in the inner shell; strict concentricity requirements on the two shells; development of nanoporous, low-density, metallic foams for structural support of the inner shell and hydrodynamic instability mitigation; and effective control of perturbation growth on the high-Atwood number interface between the DT fuel and the high-Z inner shell. Recent progress in DS ignition target designs using vacuum hohlraums is described, offering the potential for low levels of laser backscatter from stimulated Raman and Brillouin processes. In addition, vacuum hohlraums have the operational advantages of room temperature fielding and fabrication simplicity, as well as benefiting from extensive benchmarking on the Nova and Omega laser facilities. As an alternative to standard cylindrical hohlraums, a rugby-shaped geometry is also introduced that may provide energetics and symmetry tuning benefits for more robust DS designs with yields exceeding 10 MJ for 2 MJ of 3w laser energy. The recent progress in hohlraum designs and required advanced materials development are scheduled to culminate in a prototype demonstration of a NIF-scale ignition-ready DS in 2007. [1] P. Amendt et al., PoP 9, 2221 (2002). [2] J.D. Lindl et al., PoP 11, 339 (2004). [3] M.N. Chizhkov et al., Laser Part. Beams 23, 261 (2005). In collaboration with C. Cerjan, A. Hamza, J. Milovich and H. Robey.

  6. MICRO AUTO GASIFICATION SYSTEM: EMISSIONS ...

    Science.gov (United States)

    A compact, CONEX-housed waste to energy unit, Micro Auto Gasification System (MAGS), was characterized for air emissions from burning of military waste types. The MAGS unit is a dual chamber gasifier with a secondary diesel-fired combustor. Eight tests were conducted with multiple waste types in a 7-day period at the Kilauea Military Camp in Hawai’i. The emissions characterized were chosen based on regulatory emissions limits as well as their ability to cause adverse health effects on humans: particulate matter (PM), mercury, heavy metals, volatile organic compounds (VOCs), polyaromatic hydrocarbons (PAHs), and polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Three military waste feedstock compositions reflecting the variety of wastes to be encountered in theatre were investigated: standard waste (SW), standard waste with increased plastic content (HP), standard waste without SW food components but added first strike ration (FSR) food and packaging material (termed FSR). A fourth waste was collected from the Kilauea dumpster that served the dining facility and room lodging (KMC). Limited scrubber water and solid ash residue samples were collected to obtain a preliminary characterization of these effluents/residues.Gasifying SW, HP, and KMC resulted in similar PCDD/PCDF stack concentrations, 0.26-0.27 ng TEQ/m3 at 7% O2, while FSR waste generated a notably higher stack concentration of 0.68 ng TEQ/m3 at 7% O2. The PM emission

  7. Ignition of a lean PRF/air mixture under RCCI/SCCI conditions: Chemical aspects

    KAUST Repository

    Luong, Minh Bau; Yu, Gwang Hyeon; Chung, Suk-Ho; Yoo, Chun Sang

    2016-01-01

    numerical simulation (DNS) data with chemical explosive mode (CEM) analysis. CEMA is adopted to provide fundamental insights into the ignition process by identifying controlling species and elementary reactions at different locations and times. It is found

  8. Laser Ignition Microthruster Experiments on KKS-1

    Science.gov (United States)

    Nakano, Masakatsu; Koizumi, Hiroyuki; Watanabe, Masashi; Arakawa, Yoshihiro

    A laser ignition microthruster has been developed for microsatellites. Thruster performances such as impulse and ignition probability were measured, using boron potassium nitrate (B/KNO3) solid propellant ignited by a 1 W CW laser diode. The measured impulses were 60 mNs ± 15 mNs with almost 100 % ignition probability. The effect of the mixture ratios of B/KNO3 on thruster performance was also investigated, and it was shown that mixture ratios between B/KNO3/binder = 28/70/2 and 38/60/2 exhibited both high ignition probability and high impulse. Laser ignition thrusters designed and fabricated based on these data became the first non-conventional microthrusters on the Kouku Kousen Satellite No. 1 (KKS-1) microsatellite that was launched by a H2A rocket as one of six piggyback satellites in January 2009.

  9. Auto Carrier Transporter Loading and Unloading Improvement

    National Research Council Canada - National Science Library

    Miller, Brian

    2003-01-01

    .... Any reduction in time and energy will result in a significant savings of money. The intent of this research is to develop an algorithm to solve the Auto Carrier Transport Pickup and Delivery Problem...

  10. Line Generalization and AutoCAD Map

    Directory of Open Access Journals (Sweden)

    Nada Vučetić

    2001-01-01

    Full Text Available The paper offers the results of original research made on the application of AutoCAD Map in line generalisation. The differences and similarities have been found out between the Douglas-Peucker method and the method of line simplification that is incorporated in AutoCAD Map. There have been also the inaccuracies found out in AutoCAD Map manual relating to the issues of buffer width and tolerance, and the line width before and after simplification. The paper gives recommendations about pseudo nodes dissolving. It has been noticed that AutoCAD Map simplification method is not independent of the order of points. The application of the method is illustrated by an example of coastal line of Istria.

  11. AutoCAD-To-NASTRAN Translator Program

    Science.gov (United States)

    Jones, A.

    1989-01-01

    Program facilitates creation of finite-element mathematical models from geometric entities. AutoCAD to NASTRAN translator (ACTON) computer program developed to facilitate quick generation of small finite-element mathematical models for use with NASTRAN finite-element modeling program. Reads geometric data of drawing from Data Exchange File (DXF) used in AutoCAD and other PC-based drafting programs. Written in Microsoft Quick-Basic (Version 2.0).

  12. Computing Mass Properties From AutoCAD

    Science.gov (United States)

    Jones, A.

    1990-01-01

    Mass properties of structures computed from data in drawings. AutoCAD to Mass Properties (ACTOMP) computer program developed to facilitate quick calculations of mass properties of structures containing many simple elements in such complex configurations as trusses or sheet-metal containers. Mathematically modeled in AutoCAD or compatible computer-aided design (CAD) system in minutes by use of three-dimensional elements. Written in Microsoft Quick-Basic (Version 2.0).

  13. Studies into laser ignition of confined pyrotechnics

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, S.R.; Russell, D.A. [Centre for Applied Laser Spectroscopy, DASSR, Defence Academy, Cranfield University, Shrivenham, Swindon (United Kingdom)

    2008-10-15

    Ignition tests were carried out on three different pyrotechnics using laser energy from the multimode output from an Ar-Ion laser (av) at 500 nm and a near-IR diode laser pigtailed to a fibre optic cable and operating at 808 nm. The pyrotechnics investigated were: G20 black powder, SR44 and SR371C. The confined ignition tests were conducted in a specially designed ignition chamber. Pyrotechnics were ignited by a free space beam entering the chamber through an industrial sapphire window in the case of the Ar-ion laser. For the NIR diode laser, fibre was ducted through a block into direct contact with the pyrotechnic. The Ar-Ion laser was chosen as this was found to ignite all three pyrotechnics in the unconfined condition. It also allowed for a direct comparison of confined/unconfined results to be made. The threshold laser flux densities to initiate reproducible ignitions at this wavelength were found to be between {proportional_to}12.7 and {proportional_to}0.16 kW cm{sup -2}. Plotted on the ignition maps are the laser flux densities versus the start of ignition times for the three confined pyrotechnics. It was found from these maps that the times for confined ignition were substantially lower than those obtained for unconfined ignition under similar experimental conditions. For the NIR diode laser flux densities varied between {proportional_to}6.8 and {proportional_to}0.2 kW cm{sup -2}. The minimum ignition times for the NIR diode laser for SR371C ({proportional_to}11.2 ms) and G20 ({proportional_to}17.1 ms) were faster than those achieved by the use of the Ar-ion laser. However, the minimum ignition time was shorter ({proportional_to}11.7 ms) with the Ar-ion laser for SR44. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  14. AutoCAD 2014 review for certification official certification preparation

    CERN Document Server

    ASCENT center for technical knowledge

    2014-01-01

    The AutoCAD® 2014 Review for Certification book is intended for users of AutoCAD® preparing to complete the AutoCAD 2014 Certified Professional exam. This book contains a collection of relevant instructional topics, practice exercises, and review questions from the Autodesk Official Training Guides (AOTG) from ASCENT - Center for Technical Knowledge pertaining specifically to the Certified Professional exam topics and objectives. This book is intended for experienced users of AutoCAD in preparation for certification. New users of AutoCAD should refer to the AOTG training guides from ASCENT, such as AutoCAD/AutoCAD LT 2014 Fundamentals, for more comprehensive instruction.

  15. Electron Shock Ignition of Inertial Fusion Targets

    International Nuclear Information System (INIS)

    Shang, W. L.; Betti, R.; Hu, S. X.; Woo, K.; Hao, L.

    2017-01-01

    Here, it is shown that inertial fusion targets designed with low implosion velocities can be shock ignited using laser–plasma interaction generated hot electrons (hot-e) to obtain high-energy gains. These designs are robust to multimode asymmetries and are predicted to ignite even for significantly distorted implosions. Electron shock ignition requires tens of kilojoules of hot-e, which can only be produced on a large laser facility like the National Ignition Facility, with the laser to hot-e conversion efficiency greater than 10% at laser intensities ~10 16 W/cm 2 .

  16. Modelling piloted ignition of wood and plastics

    International Nuclear Information System (INIS)

    Blijderveen, Maarten van; Bramer, Eddy A.; Brem, Gerrit

    2012-01-01

    Highlights: ► We model piloted ignition times of wood and plastics. ► The model is applied on a packed bed. ► When the air flow is above a critical level, no ignition can take place. - Abstract: To gain insight in the startup of an incinerator, this article deals with piloted ignition. A newly developed model is described to predict the piloted ignition times of wood, PMMA and PVC. The model is based on the lower flammability limit and the adiabatic flame temperature at this limit. The incoming radiative heat flux, sample thickness and moisture content are some of the used variables. Not only the ignition time can be calculated with the model, but also the mass flux and surface temperature at ignition. The ignition times for softwoods and PMMA are mainly under-predicted. For hardwoods and PVC the predicted ignition times agree well with experimental results. Due to a significant scatter in the experimental data the mass flux and surface temperature calculated with the model are hard to validate. The model is applied on the startup of a municipal waste incineration plant. For this process a maximum allowable primary air flow is derived. When the primary air flow is above this maximum air flow, no ignition can be obtained.

  17. Orchestrating Shots for the National Ignition Facility (NIF)

    International Nuclear Information System (INIS)

    Mathisen, D G; Bettenhausen, R C; Beeler, R G; Bowers, G A; Carey, R W; Casavant, D D; Cline, B D; Demaret, R D; Domyancic, D M; Elko, S D; Fisher, J M; Krammen, J E; Lagin, L J; Ludwigsen, A P; Patterson, R W; Sanchez, R J; Stout, E A

    2005-01-01

    The National Ignition Facility (NIF), currently under construction at the Lawrence Livermore National Laboratory, is a stadium-sized facility containing a 192-beam, 1.8 Megajoule, 500-Terawatt, ultra-violet laser system together with a 10-meter diameter target chamber with room for nearly 100 experimental diagnostics. When completed, NIF will be the world's largest and most energetic laser experimental system, providing an international center to study inertial confinement fusion and physics of matter at extreme densities and pressures. The NIF is operated by the Integrated Computer Control System (ICCS), which is a layered architecture of over 700 lower-level front-end processors attached to nearly 60,000 control points and coordinated by higher-level supervisory subsystems in the main control room. A shot automation framework has been developed and deployed during the past year to orchestrate and automate shots performed at the NIF using the ICCS. The Shot Automation framework is designed to automate 4-8 hour shot sequences, that includes deriving shot goals from an experiment definition, set up of the laser and diagnostics, automatic alignment of laser beams, and a countdown to charge and fire the lasers. These sequences consist of set of preparatory verification shots, leading to amplified system shots followed by post-shot analysis and archiving. The framework provides for a flexible, model-based work-flow execution, driven by scripted automation called macro steps. The shot director software is the orchestrating component of a very flexible automation layer which allows us to define, coordinate and reuse simpler automation sequences. This software provides a restricted set of shot life cycle state transitions to 26 collaboration supervisors that automate 8-laser beams (bundle) and a common set of shared resources. Each collaboration supervisor commands approximately 10 subsystem shot supervisors that perform automated control and status verification

  18. Analysis on the workspace of palletizing robot based on AutoCAD

    Science.gov (United States)

    Li, Jin-quan; Zhang, Rui; Guan, Qi; Cui, Fang; Chen, Kuan

    2017-10-01

    In this paper, a four-degree-of-freedom articulated palletizing robot is used as the object of research. Based on the analysis of the overall configuration of the robot, the kinematic mathematical model is established by D-H method to figure out the workspace of the robot. In order to meet the needs of design and analysis, using AutoCAD secondary development technology and AutoLisp language to develop AutoCAD-based 2D and 3D workspace simulation interface program of palletizing robot. At last, using AutoCAD plugin, the influence of structural parameters on the shape and position of the working space is analyzed when the structure parameters of the robot are changed separately. This study laid the foundation for the design, control and planning of palletizing robots.

  19. Ignition et oxydation des particules de combustible solide pulvérisé Ignition and Oxidation of Pulverized Solid Fuel

    Directory of Open Access Journals (Sweden)

    De Soete G. G.

    2006-11-01

    the rate of heterogeneous combustion can reach its normal steady state, which is practically the same as that of char. At temperatures between the ignition temperature of the solid fuel and the extinction temperature of residual char, combustion is incomplete and extinction occurs at a devolatilization degree that is all the greater as the temperature is high. This phenomenon can be qualitively explained by the standard thermal ignition theory when it is applied to the specific case of pyrolyzable solid fuels. Ignition temperatures as well as ignition delays have been determined for a great many lower- and higher-rank solid fuels (coals, cokes, asphaltenes, soot, wood, graphite. An analysis of the experimental rate of heterogeneous combustion, and especially of the apparent activation temperature, and its dependency with regard to particle size and oxygen concentration, shows that this combustion is controlled under test conditions by CO desorption and that it occurs mainly in the mixed kinetico-diffusional regime. Investigations of the dependency of ignition delays with regard to temperature, to particle size and to oxygen partial pressure suggest that reactions occur in a pure kinetic regime during such delays and that the desorption reaction product is mainly CO.

  20. First wall thermomechanical stress analysis in a fusion ignition experiment

    International Nuclear Information System (INIS)

    Rodin, G.; Carrera, R.; Howell, J.; Hwang, Y.L.; Montalvo, E.; Ordonez, C.; Dong, J.Q.

    1990-01-01

    The fusion ignition experiment IGNITEX + has been proposed as a low cost means of producing and controlling fusion ignited plasmas for scientific study. A single-turn-coil tokamak plasmas for scientific study. A single-turn-coil tokamak cryogenically precooled at liquid nitrogen temperature is used to produce 20 T fields and 12 MA plasma currents so that high-density ohmic ignition is possible. The high-field, high-density operation should maintain the plasma relatively free of wall impurities. In order to minimize plasma cooling, a low-Z first wall is considered for IGNITEX. The IGNITEX design philosophy emphasizes simplicity and low cost. A limiterless, smooth first will without files and plates is proposed. A low-Z material is applied by plasma jet techniques over a resistive vacuum vessel. This design is thought to be adequate for a magnetic fusion ignition experiment. Maintenance and operation of the first wall system is significantly simplified when compared to conventional designs

  1. National Ignition Facility environmental protection systems

    International Nuclear Information System (INIS)

    Mintz, J.M.; Reitz, T.C.; Tobin, M.T.

    1994-06-01

    The conceptual design of Environmental Protection Systems (EPS) for the National Ignition Facility (NIF) is described. These systems encompass tritium and activated debris handling, chamber, debris shield and general decontamination, neutron and gamma monitoring, and radioactive, hazardous and mixed waste handling. Key performance specifications met by EPS designs include limiting the tritium inventory to 300 Ci and total tritium release from NIF facilities to less than 10 Ci/yr. Total radiation doses attributable to NIF shall remain below 10 mrem/yr for any member of the general public and 500 mrem/yr for NIF staff. ALARA-based design features and operational procedures will, in most cases, result in much lower measured exposures. Waste minimization, improved cycle time and reduced exposures all result from the proposed CO2 robotic arm cleaning and decontamination system, while effective tritium control is achieved through a modern system design based on double containment and the proven detritiation technology

  2. Final Rule for Control of Emissions From New Marine Compression-Ignition Engines at or Above 2.5 Liters Per Cylinder

    Science.gov (United States)

    The near-term, Tier 1 standards in this rule are equivalent to the internationally negotiated emission limits for oxides of nitrogen (NOx). These standards will go into effect in 2004 and are based on readily available emission-control technology.

  3. Coil-On-Plug Ignition for LOX/Methane Liquid Rocket Engines in Thermal Vacuum Environments

    Science.gov (United States)

    Melcher, John C.; Atwell, Matthew J.; Morehead, Robert L.; Hurlbert, Eric A.; Bugarin, Luz; Chaidez, Mariana

    2017-01-01

    A coil-on-plug ignition system has been developed and tested for Liquid Oxygen (LOX) / liquid methane rocket engines operating in thermal vacuum conditions. The igniters were developed and tested as part of the Integrated Cryogenic Propulsion Test Article (ICPTA), previously tested as part of the Project Morpheus test vehicle. The ICPTA uses an integrated, pressure-fed, cryogenic LOX/methane propulsion system including a reaction control system (RCS) and a main engine. The ICPTA was tested at NASA Glenn Research Center's Plum Brook Station in the Spacecraft Propulsion Research Facility (B-2) under vacuum and thermal vacuum conditions. In order to successfully demonstrate ignition reliability in the vacuum conditions and eliminate corona discharge issues, a coil-on-plug ignition system has been developed. The ICPTA uses spark-plug ignition for both the main engine igniter and the RCS. The coil-on-plug configuration eliminates the conventional high-voltage spark plug cable by combining the coil and the spark-plug into a single component. Prior to ICPTA testing at Plum Brook, component-level reaction control engine (RCE) and main engine igniter testing was conducted at NASA Johnson Space Center (JSC), which demonstrated successful hot-fire ignition using the coil-on-plug from sea-level ambient conditions down to 10(exp.-2) torr. Integrated vehicle hot-fire testing at JSC demonstrated electrical and command/data system performance. Lastly, Plum Brook testing demonstrated successful ignitions at simulated altitude conditions at 30 torr and cold thermal-vacuum conditions at 6 torr. The test campaign successfully proved that coil-on-plug technology will enable integrated LOX/methane propulsion systems in future spacecraft.

  4. Electrically heated 3D-macro cellular SiC structures for ignition and combustion application

    International Nuclear Information System (INIS)

    Falgenhauer, Ralf; Rambacher, Patrick; Schlier, Lorenz; Volkert, Jochen; Travitzky, Nahum; Greil, Peter; Weclas, Miroslaw

    2017-01-01

    Highlights: • 3D-printed macro cellular SiC structure. • Directly integrated electrically heated ignition element used in combustion reactor. • Experimental investigation of the ignition process. - Abstract: The paper describes different aspects of porous combustion reactor operation especially at cold start conditions. Under cold start conditions it is necessary to increase the internal energy of the combustion reactor, to accumulate enough energy inside its solid phase and to reach at least the ignition temperature on the reactors inner surface. The most practicable method to preheat a cold porous reactor is to use its surface as a flame holder and to apply free flame combustion as a heat source for the preheating process. This paper presents a new electrically heated ignition element, which gets integrated in a three dimensional macro-cellular SiSiC reactor structure. For the development of the ignition element it was assumed, that the element is made of the same material as the combustion reactor itself and is fully integrated within the three-dimensional macro-cellular structure of the combustion reactor. Additive manufacturing like three-dimensional (3D) printing permits the production of regular SiSiC structures with constant strut thickness and a defined current flow path. To get a controlled temperature distribution on the ignition element it is necessary to control the current density distribution in the three-dimensional macro-cellular reactor structure. The ignition element used is designed to be an electrical resistance in an electric current system, converting flowing current into heat with the goal to get the highest temperature in the ignition region (glow plug). First experiments show that the ignition element integrated in a combustion reactor exhibits high dynamics and can be heated to the temperatures much above 1000 °C in a very short time (approx. 800 ms) for current of I = 150 A.

  5. Projecting pipeline construction by AutoDesk Map; Projektierung von Rohrleitungsbaumassnahmen mit AutoDesk Map

    Energy Technology Data Exchange (ETDEWEB)

    Taschendorf, M.; Voigtlaender, M. [Hamburger Wasserwerke GmbH, Hamburg (Germany)

    2005-12-15

    Presented is AutoDesk Map, which enables the construction and planning of big grids for water- and gas supply. In this example industrial equipment is driven as objects in AutoDesk Map. Therefore the consistence of the data is guaranted and comprehensive CAD functions are available for industrial equipment and topologies. (GL)

  6. Testing First-Order Logic Axioms in AutoCert

    Science.gov (United States)

    Ahn, Ki Yung; Denney, Ewen

    2009-01-01

    AutoCert [2] is a formal verification tool for machine generated code in safety critical domains, such as aerospace control code generated from MathWorks Real-Time Workshop. AutoCert uses Automated Theorem Provers (ATPs) [5] based on First-Order Logic (FOL) to formally verify safety and functional correctness properties of the code. These ATPs try to build proofs based on user provided domain-specific axioms, which can be arbitrary First-Order Formulas (FOFs). These axioms are the most crucial part of the trusted base, since proofs can be submitted to a proof checker removing the need to trust the prover and AutoCert itself plays the part of checking the code generator. However, formulating axioms correctly (i.e. precisely as the user had really intended) is non-trivial in practice. The challenge of axiomatization arise from several dimensions. First, the domain knowledge has its own complexity. AutoCert has been used to verify mathematical requirements on navigation software that carries out various geometric coordinate transformations involving matrices and quaternions. Axiomatic theories for such constructs are complex enough that mistakes are not uncommon. Second, adjusting axioms for ATPs can add even more complexity. The axioms frequently need to be modified in order to have them in a form suitable for use with ATPs. Such modifications tend to obscure the axioms further. Thirdly, speculating validity of the axioms from the output of existing ATPs is very hard since theorem provers typically do not give any examples or counterexamples.

  7. AutoCAD 2012 and AutoCAD LT 2012 Bible

    CERN Document Server

    Finkelstein, Ellen

    2011-01-01

    The latest version of this perennial favorite, in-depth, reference-tutorial This top-selling book has been updated by AutoCAD guru and author Ellen Finkelstein to provide you with the very latest coverage of both AutoCAD 2012 and AutoCAD LT 2012. It begins with a Quick Start tutorial, so you start creating right away. From there, the book covers so much in-depth material on AutoCAD that it is said that even Autodesk employees keep this comprehensive book at their desks. A DVD is included that features before-and-after drawings of all the tutorials and plenty of great examples from AutoCAD prof

  8. Self-Programmed Counseling and Self-Programmed Control Manual. A Guide to Self-Image Development with Emphasis on the Chicano Student. Student's Guide = Manual de Sistema de Consejo Auto Programado y Control Auto Programado. Una Guia Para el Desarrollo de La Imagen Propia Con un Enfasis en el Estudiante Chicano.

    Science.gov (United States)

    Mireles, S. Raymond

    Self-Programmed Counseling, the instructor's guidance, and Self-Programmed Control (SPC), the student's response, was initially developed by Title III Project USTED (United Students and Teachers for Educational Development) for Mexican American college students on academic probation to use on a non-credit, special group counseling basis. As part…

  9. Studies on the robustness of shock-ignited laser fusion targets

    International Nuclear Information System (INIS)

    Atzeni, S; Schiavi, A; Marocchino, A

    2011-01-01

    Several aspects of the sensitivity of a shock-ignited inertial fusion target to variation of parameters and errors or imperfections are studied by means of one-dimensional and two-dimensional numerical simulations. The study refers to a simple all-DT target, initially proposed for fast ignition (Atzeni et al 2007 Phys. Plasmas 7 052702) and subsequently shown to be also suitable for shock ignition (Ribeyre et al 2009 Plasma Phys. Control. Fusion 51 015013). It is shown that the growth of both Richtmyer-Meshkov and Rayleigh-Taylor instability (RTI) at the ablation front is reduced by laser pulses with an adiabat-shaping picket. An operating window for the parameters of the ignition laser spike is described; the threshold power depends on beam focusing and synchronization with the compression pulse. The time window for spike launch widens with beam power, while the minimum spike energy is independent of spike power. A large parametric scan indicates good tolerance (at the level of a few percent) to target mass and laser power errors. 2D simulations indicate that the strong igniting shock wave plays an important role in reducing deceleration-phase RTI growth. Instead, the high hot-spot convergence ratio (ratio of initial target radius to hot-spot radius at ignition) makes ignition highly sensitive to target mispositioning.

  10. Physical characteristics of welding arc ignition process

    Science.gov (United States)

    Shi, Linan; Song, Yonglun; Xiao, Tianjiao; Ran, Guowei

    2012-07-01

    The existing research of welding arc mainly focuses on the stable combustion state and the research on the mechanism of welding arc ignition process is quite lack. The tungsten inert gas(TIG) touch arc ignition process is observed via a high speed camera and the high time resolution spectral diagnosis system. The changing phenomenon of main ionized element provided the electrons in the arc ignition is found. The metallic element is the main contributor to provide the electrons at the beginning of the discharging, and then the excitated shielding gas element replaces the function of the metallic element. The electron density during the period of the arc ignition is calculated by the Stark-broadened lines of Hα. Through the discussion with the repeatability in relaxation phenomenon, the statistical regularity in the arc ignition process is analyzed. The similar rules as above are observed through the comparison with the laser-assisted arc ignition experiments and the metal inert gas(MIG) arc ignition experiments. This research is helpful to further understanding on the generation mechanism of welding arc ignition and also has a certain academic and practical significance on enriching the welding physical theoretical foundation and improving the precise monitoring on automatic arc welding process.

  11. Modelling piloted ignition of wood and plastics

    NARCIS (Netherlands)

    Blijderveen, M.; Bramer, Eduard A.; Brem, Gerrit

    2012-01-01

    To gain insight in the startup of an incinerator, this article deals with piloted ignition. A newly developed model is described to predict the piloted ignition times of wood, PMMA and PVC. The model is based on the lower flammability limit and the adiabatic flame temperature at this limit. The

  12. Heating and ignition of small wood cylinders

    Science.gov (United States)

    Wallace L. Fons

    1950-01-01

    The literature provides limited information on the time of ignition of wood under conditions of rapid heating such as occur in forest and structure fires. An investigation was made of ease of ignition as affected by such physical properties of wood as initial temperature, size, and moisture content and by temperature of ambient gas or rate of heating. Temperature-time...

  13. Target Diagnostics Supports NIF's Path to Ignition

    International Nuclear Information System (INIS)

    Shelton, R.

    2011-01-01

    The physics requirements derived from the National Ignition Facility (NIF) experimental campaigns are leading to a wide variety of target diagnostics. Software development for the control and analysis of these diagnostics is included in the NIF Integrated Computer Control System, Diagnostic Control System and Data Visualization. These projects implement the configuration, controls, data analysis and visual representation of most of these diagnostics. To date, over 40 target diagnostics have been developed to support NIF experiments. In 2011 diagnostics were developed or enhanced to measure Ignition performance in a high neutron yield environment. Performance is optimized around four key variables: Adiabat (a) which is the strength and timing of four shocks delivered to the target, Velocity (V) of the imploding target, Mix (M) is the uniformity of the burn, and the Shape (S) of the imploding Deuterium Tritium (DT) hot spot. The diagnostics used to measure each of these parameters is shown in figure 1. Adiabat is measured using the Velocity Interferometer System for Any Reflector (VISAR) diagnostic consisting of three streak cameras. To provide for more accurate adiabat measurements the VISAR streak cameras were enhanced in FY11 with a ten comb fiducial signal controller to allow for post shot correction of the streak camera sweep non-linearity. Mix is measured by the Neutron Time of Flight (NTOF) and Radiochemical Analysis of Gaseous Samples (RAGS) diagnostics. To accommodate high neutron yield shots, NTOF diagnostic controls are being modified to use Mach Zehnder interferometer signals to allow the digitizers to be moved from near the target chamber to the neutron shielded diagnostic mezzanine. In December 2011 the first phase of RAGS diagnostic commissioning will be completed. This diagnostic will analyze the tracers that are added to NIF target capsules that undergo nuclear reactions during the shot. These gases are collected and purified for nuclear counting by

  14. Isochoric Implosions for Fast Ignition

    International Nuclear Information System (INIS)

    Clark, D S; Tabak, M

    2007-01-01

    Various gain models have shown the potentially great advantages of Fast Ignition (FI) Inertial Confinement Fusion (ICF) over its conventional hot spot ignition counterpart [e.g., S. Atzeni, Phys. Plasmas 6, 3316 (1999); M. Tabak et al., Fusion Sci. and Technology 49, 254 (2006)]. These gain models, however, all assume nearly uniform-density fuel assemblies. In contrast, conventional ICF implosions yield hollowed fuel assemblies with a high-density shell of fuel surrounding a low-density, high-pressure hot spot. Hence, to realize fully the advantages of FI, an alternative implosion design must be found which yields nearly isochoric fuel assemblies without substantial hot spots. Here, it is shown that a self-similar spherical implosion of the type originally studied by Guderley [Luftfahrtforschung 19, 302 (1942)] may be employed to yield precisely such quasi-isochoric imploded states. The difficulty remains, however, of accessing these self-similarly imploding configurations from initial conditions representing an actual ICF target, namely a uniform, solid-density shell at rest. Furthermore, these specialized implosions must be realized for practicable drive parameters and at the scales and energies of interest in ICF. A direct-drive implosion scheme is presented which meets all of these requirements and reaches a nearly isochoric assembled density of 300 g=cm 3 and areal density of 2.4 g=cm 2 using 485 kJ of laser energy

  15. Sensitivity to external signals and synchronization properties of a non-isochronous auto-oscillator with delayed feedback

    Science.gov (United States)

    Tiberkevich, Vasil S.; Khymyn, Roman S.; Tang, Hong X.; Slavin, Andrei N.

    2014-01-01

    For auto-oscillators of different nature (e.g. active cells in a human heart under the action of a pacemaker, neurons in brain, spin-torque nano-oscillators, micro and nano-mechanical oscillators, or generating Josephson junctions) a critically important property is their ability to synchronize with each other. The synchronization properties of an auto oscillator are directly related to its sensitivity to external signals. Here we demonstrate that a non-isochronous (having generation frequency dependent on the amplitude) auto-oscillator with delayed feedback can have an extremely high sensitivity to external signals and unusually large width of the phase-locking band near the boundary of the stable auto-oscillation regime. This property could be used for the development of synchronized arrays of non-isochronous auto-oscillators in physics and engineering, and, for instance, might bring a better fundamental understanding of ways to control a heart arrythmia in medicine.

  16. [Clinical overview of auto-inflammatory diseases].

    Science.gov (United States)

    Georgin-Lavialle, S; Rodrigues, F; Hentgen, V; Fayand, A; Quartier, P; Bader-Meunier, B; Bachmeyer, C; Savey, L; Louvrier, C; Sarrabay, G; Melki, I; Belot, A; Koné-Paut, I; Grateau, G

    2018-04-01

    Monogenic auto-inflammatory diseases are characterized by genetic abnormalities coding for proteins involved in innate immunity. They were initially described in mirror with auto-immune diseases because of the absence of circulating autoantibodies. Their main feature is the presence of peripheral blood inflammation in crisis without infection. The best-known auto-inflammatory diseases are mediated by interleukines that consisted in the 4 following diseases familial Mediterranean fever, cryopyrinopathies, TNFRSF1A-related intermittent fever, and mevalonate kinase deficiency. Since 10 years, many other diseases have been discovered, especially thanks to the progress in genetics. In this review, we propose the actual panorama of the main known auto-inflammatory diseases. Some of them are recurrent fevers with crisis and remission; some others evaluate more chronically; some are associated with immunodeficiency. From a physiopathological point of view, we can separate diseases mediated by interleukine-1 and diseases mediated by interferon. Then some polygenic inflammatory diseases will be shortly described: Still disease, Schnitzler syndrome, aseptic abscesses syndrome. The diagnosis of auto-inflammatory disease is largely based on anamnesis, the presence of peripheral inflammation during attacks and genetic analysis, which are more and more performant. Copyright © 2018 Société Nationale Française de Médecine Interne (SNFMI). Published by Elsevier SAS. All rights reserved.

  17. Sensorless control of electromagnetic actuators for gas valves in spark ignition engines; Sensorlose Regelung elektromagnetischer Aktuatoren fuer die Betaetigung von Gaswechselventilen im Otto-Motor

    Energy Technology Data Exchange (ETDEWEB)

    Butzmann, S.

    2000-07-01

    A method for sensorless control of the impact speed of the armature of electromagnetic actuators is presented and described in great detail. The control algorithm was implemented in a compact electronic control unit for a 4-cylinder, 16-valve engine and was tested both in the laboratory and in a real engine. The method was first presented in September 1999 at the Frankfurt IHH, where it met with great interest. [German] In dieser Arbeit wurde ein Verfahren zur sensorlosen Regelung der Aufsetzgeschwindigkeit des Ankers bei elektromagnetischen Aktuatoren vorgestellt. Um den Anker zwischen den beiden Seiten des Luftspalts zu bewegen, werden zwei Elektromagnete abwechselnd bestromt, die Bewegung wird dabei von zwei Federn unterstuetzt. Fliesst waehrend eines solchen Umschwingvorgangs ein konstanter Strom durch die Spulen, so nimmt waehrend der Annaeherung an die Polflaeche die Magnetkraft mit der Luftspaltlaenge 1/l{sub L}{sup 2} zu, waehrend die entgegengesetzt wirkende Federkraft nur linear mit der Luftspaltlaenge l{sub L} steigt. Dies fuehrt prinzipiell zu einer unerwuenschten Beschleunigung des Ankers am Ende der Bewegung und damit zu einem harten Aufprall, der Laerm erzeugt und die Aktuatorlebensdauer reduziert. Ausgehend vom idealen Verfahren der zeitoptimalen Regelung, welches allerdings hohe Anforderungen an Sensorik und Rechenleistung stellt, wurde ein Algorithmus hergeleitet, welcher die zur Regelung der Aufsetzgeschwindigkeit erforderlichen Signale aus dem Stromverlauf in den Aktuatorspulen ableitet. Das neue Regelverfahren umgeht daher die Probleme, die durch den Einsatz von Sensoren entstehen. Waehrend der Ankerbewegung werden die Spulen zusaetzlich stimuliert, um eine hoehere Observationsgenauigkeit zu erzielen. Durch Adaption zwischen zwei aufeinanderfolgenden Ventilbetaetigungen und Regelung der Bewegung waehrend der Flugphase kann die Aufsetzgeschwindigkeit des Ankers praezise geregelt werden. Gleichzeitig konnte die zur Regelung erforderliche

  18. Combustion Mode Design with High Efficiency and Low Emissions Controlled by Mixtures Stratification and Fuel Reactivity

    Directory of Open Access Journals (Sweden)

    Hu eWang

    2015-08-01

    Full Text Available This paper presents a review on the combustion mode design with high efficiency and low emissions controlled by fuel reactivity and mixture stratification that have been conducted in the authors’ group, including the charge reactivity controlled homogeneous charge compression ignition (HCCI combustion, stratification controlled premixed charge compression ignition (PCCI combustion, and dual-fuel combustion concepts controlled by both fuel reactivity and mixture stratification. The review starts with the charge reactivity controlled HCCI combustion, and the works on HCCI fuelled with both high cetane number fuels, such as DME and n-heptane, and high octane number fuels, such as methanol, natural gas, gasoline and mixtures of gasoline/alcohols, are reviewed and discussed. Since single fuel cannot meet the reactivity requirements under different loads to control the combustion process, the studies related to concentration stratification and dual-fuel charge reactivity controlled HCCI combustion are then presented, which have been shown to have the potential to achieve effective combustion control. The efforts of using both mixture and thermal stratifications to achieve the auto-ignition and combustion control are also discussed. Thereafter, both charge reactivity and mixture stratification are then applied to control the combustion process. The potential and capability of thermal-atmosphere controlled compound combustion mode and dual-fuel reactivity controlled compression ignition (RCCI/highly premixed charge combustion (HPCC mode to achieve clean and high efficiency combustion are then presented and discussed. Based on these results and discussions, combustion mode design with high efficiency and low emissions controlled by fuel reactivity and mixtures stratification in the whole operating range is proposed.

  19. Low Load Limit Extension for Gasoline Compression Ignition Using Negative Valve Overlap Strategy

    KAUST Repository

    Vallinayagam, R.

    2018-04-03

    Gasoline compression ignition (GCI) is widely studied for the benefits of simultaneous reduction in nitrogen oxide (NO) and soot emissions without compromising the engine efficiency. Despite this advantage, the operational range for GCI is not widely expanded, as the auto-ignition of fuel at low load condition is difficult. The present study aims to extend the low load operational limit for GCI using negative valve overlap (NVO) strategy. The engine used for the current experimentation is a single cylinder diesel engine that runs at an idle speed of 800 rpm with a compression ratio of 17.3. The engine is operated at homogeneous charge compression ignition (HCCI) and partially premixed combustion (PPC) combustion modes with the corresponding start of injection (SOI) at 180 CAD (aTDC) and 30 CAD (aTDC), respectively. In the presented work, intake air temperature is used as control parameter to maintain combustion stability at idle and low load condition, while the intake air pressure is maintained at 1 bar (ambient). The engine is equipped with variable valve cam phasers that can phase both inlet and exhaust valves from the original timing. For the maximum cam phasing range (56 CAD) at a valve lift of 0.3 mm, the maximum allowable positive valve overlap was 20 CAD. In the present study, the exhaust cam is phased to 26 CAD and 6 CAD and the corresponding NVO is noted to be 10 CAD and 30 CAD, respectively. With exhaust cam phasing adjustment, the exhaust valve is closed early to retain hot residual gases inside the cylinder. As such, the in-cylinder temperature is increased and a reduction in the required intake air temperature to control combustion phasing is possible. For a constant combustion phasing of 3 CAD (aTDC), a minimum load of indicated mean effective pressure (IMEP) = 1 bar is attained for gasoline (RON = 91) at HCCI and PPC modes. The coefficient of variance was observed to below 5% at these idle and low load conditions. At the minimum load point, the

  20. AutoCAD platform customization user interface and beyond

    CERN Document Server

    Ambrosius, Lee

    2014-01-01

    Make AutoCAD your own with powerful personalization options Options for AutoCAD customization are typically the domain of administrators, but savvy users can perform their own customizations to personalize AutoCAD. Until recently, most users never thought to customize the AutoCAD platform to meet their specific needs, instead leaving it to administrators. If you are an AutoCAD user who wants to ramp up personalization options in your favorite software, AutoCAD Platform Customization: User Interface and Beyond is the perfect resource for you. Author Lee Ambrosius is recognized as a leader in Au

  1. Human neutrophils in auto-immunity.

    Science.gov (United States)

    Thieblemont, Nathalie; Wright, Helen L; Edwards, Steven W; Witko-Sarsat, Véronique

    2016-04-01

    Human neutrophils have great capacity to cause tissue damage in inflammatory diseases via their inappropriate activation to release reactive oxygen species (ROS), proteases and other tissue-damaging molecules. Furthermore, activated neutrophils can release a wide variety of cytokines and chemokines that can regulate almost every element of the immune system. In addition to these important immuno-regulatory processes, activated neutrophils can also release, expose or generate neoepitopes that have the potential to break immune tolerance and result in the generation of autoantibodies, that characterise a number of human auto-immune diseases. For example, in vasculitis, anti-neutrophil cytoplasmic antibodies (ANCA) that are directed against proteinase 3 or myeloperoxidase are neutrophil-derived autoantigens and activated neutrophils are the main effector cells of vascular damage. In other auto-immune diseases, these neutrophil-derived neoepitopes may arise from a number of processes that include release of granule enzymes and ROS, changes in the properties of components of their plasma membrane as a result of activation or apoptosis, and via the release of Neutrophil Extracellular Traps (NETs). NETs are extracellular structures that contain chromatin that is decorated with granule enzymes (including citrullinated proteins) that can act as neo-epitopes to generate auto-immunity. This review therefore describes the processes that can result in neutrophil-mediated auto-immunity, and the role of neutrophils in the molecular pathologies of auto-immune diseases such as vasculitis, rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). We discuss the potential role of NETs in these processes and some of the debate in the literature regarding the role of this phenomenon in microbial killing, cell death and auto-immunity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Parallel auto-correlative statistics with VTK.

    Energy Technology Data Exchange (ETDEWEB)

    Pebay, Philippe Pierre; Bennett, Janine Camille

    2013-08-01

    This report summarizes existing statistical engines in VTK and presents both the serial and parallel auto-correlative statistics engines. It is a sequel to [PT08, BPRT09b, PT09, BPT09, PT10] which studied the parallel descriptive, correlative, multi-correlative, principal component analysis, contingency, k-means, and order statistics engines. The ease of use of the new parallel auto-correlative statistics engine is illustrated by the means of C++ code snippets and algorithm verification is provided. This report justifies the design of the statistics engines with parallel scalability in mind, and provides scalability and speed-up analysis results for the autocorrelative statistics engine.

  3. National Ignition Facility site requirements

    International Nuclear Information System (INIS)

    1996-07-01

    The Site Requirements (SR) provide bases for identification of candidate host sites for the National Ignition Facility (NIF) and for the generation of data regarding potential actual locations for the facilities. The SR supplements the NIF Functional Requirements (FR) with information needed for preparation of responses to queries for input to HQ DOE site evaluation. The queries are to include both documents and explicit requirements for the potential host site responses. The Sr includes information extracted from the NIF FR (for convenience), data based on design approaches, and needs for physical and organization infrastructure for a fully operational NIF. The FR and SR describe requirements that may require new construction or may be met by use or modification of existing facilities. The SR do not establish requirements for NIF design or construction project planning. The SR document does not constitute an element of the NIF technical baseline

  4. AutoCAD 2015 and AutoCAD LT 2015 essentials

    CERN Document Server

    Onstott, Scott

    2014-01-01

    Step-by-step instructions for the AutoCAD fundamentals AutoCAD 2015 Essentials contains 400 pages of full-color, comprehensive instruction on the world's top drafting and architecture software. This 2015 edition features architectural, manufacturing, and landscape architecture examples. And like previous editions, the detailed guide introduces core concepts using interactive tutorials and open-ended projects, which can be completed in any order, thanks to downloadable data sets (an especially useful feature for students and professionals studying for Autodesk AutoCAD certification). Unlike man

  5. AutoCAD 2012 and AutoCAD LT 2012 No Experience Required

    CERN Document Server

    Gladfelter, Donnie

    2011-01-01

    The perfect step-by-step introduction to Autodesk's powerful architectural design software With this essential guide, you'll learn how to plan, develop, document, and present a complete AutoCAD project by building a summer cabin from start to finish. You can follow each step sequentially or jump in at any point by downloading the drawing files from the book's companion web site. You'll also master all essential AutoCAD features, get a thorough grounding in the basics, learn the very latest industry standards and techniques, and quickly become productive with AutoCAD 2012.Features concise expla

  6. DNS Study of the Ignition of n-Heptane Fuel Spray under HCCI Conditions

    Science.gov (United States)

    Wang, Yunliang; Rutland, Christopher J.

    2004-11-01

    Direct numerical simulations are carried out to investigate the mixing and auto-ignition processes of n-heptane fuel spray in a turbulent field using a skeletal chemistry mechanism with 44 species and 112 reactions. For the solution of the carrier gas fluid, we use the Eulerian method, while for the fuel spray, the Lagrangian method is used. We use an eighth-order finite difference scheme to calculate spacial derivatives and a fourth-order Runge-Kutta scheme for the time integration. The initial gas temperature is 926 K and the initial gas pressure is 30 atmospheres. The initial global equivalence ratio based on the fuel concentration is around 0.4. The initial droplet diameter is 60 macrons and the droplet temperature is 300 K. Evolutions of averaged temperature, species mass fraction, heat release and reaction rate are presented. Contours of temperature and species mass fractions are presented. The objective is to understand the mechanism of ignition under Homogeneous Charged Compression Ignition (HCCI) conditions, aiming at providing some useful information of HCCI combustion, which is one of the critical issues to be resolved.

  7. Definition of Ignition in Inertial Confinement Fusion

    Science.gov (United States)

    Christopherson, A. R.; Betti, R.

    2017-10-01

    Defining ignition in inertial confinement fusion (ICF) is an unresolved problem. In ICF, a distinction must be made between the ignition of the hot spot and the propagation of the burn wave in the surrounding dense fuel. Burn propagation requires that the hot spot is robustly ignited and the dense shell exhibits enough areal density. Since most of the energy gain comes from burning the dense shell, in a scale of increasing yields, hot-spot ignition comes before high gains. Identifying this transition from hot-spot ignition to burn-wave propagation is key to defining ignition in general terms applicable to all fusion approaches that use solid DT fuel. Ad hoc definitions such as gain = 1 or doubling the temperature are not generally valid. In this work, we show that it is possible to identify the onset of ignition through a unique value of the yield amplification defined as the ratio of the fusion yield including alpha-particle deposition to the fusion yield without alphas. Since the yield amplification is a function of the fractional alpha energy fα =EαEα 2Ehs 2Ehs (a measurable quantity), it appears possible not only to define ignition but also to measure the onset of ignition by the experimental inference of the fractional alpha energy and yield amplification. This material is based upon work supported by the Department of Energy Office of Fusion Energy Services under Award Number DE-FC02-04ER54789 and National Nuclear Security Administration under Award Number DE-NA0001944.

  8. Overview of the Compact Ignition Tokamak

    International Nuclear Information System (INIS)

    Flanagan, C.A.

    1986-01-01

    The mission of CIT is to realize, study, and optimize fully ignited plasma discharges. The physics requirements have been established to provide reasonable assurance that the mission will be achieved: (1) plasma confinement guidelines consider all present scaling laws; ohmic, auxiliary heated L-mode, auxiliary heated H-mode, (2) figure-of-merit established: X = aB/q; this is proportional to ignition margin; X must be >25, (3) burn pulse duration set at ten times tau-E; an additional two times tau-E specified to heat to ignition, and (4) capability to operate both in limiter and divertor mode

  9. Development status of the ignition system for Vinci

    NARCIS (Netherlands)

    Frenken, G.; Vermeulen, E.; Bouquet, F.; Sanders, H.M.

    2002-01-01

    The development status of ignition system for the new cryogenic upper stage engine Vinci is presented. The concept differs from existing upper stage ignition systems as its functioning is engine independent. The system consists of a spark torch igniter, a highpressure igniter feed system and an

  10. Equilibrium system analysis in a tokamak ignition experiment

    International Nuclear Information System (INIS)

    Carrera, R.; Weldon, W.F.; Woodson, H.H.

    1989-10-01

    The objective of the IGNITEX Project is to produce and control ignited plasmas for scientific study in the simplest and least expensive way possible. The original concept was proposed by both physics and engineering researchers along the following line of thought. Question: Is there any theoretically simple, compact and reliable way of achieving fusion ignition according to the results of the fusion research program for the last decades? Answer: Yes. An experiment to be carried out in an ohmically heated compact tokamak device with 20 T field on plasma axis. Question: Is there any practical way to carry out that experiment at low cost in the near term? Answer: Yes. Using a single-turn coil magnet system with homopolar power supplies

  11. Equilibrium system analysis in a tokamak ignition experiment. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Carrera, R.; Weldon, W.F.; Woodson, H.H.

    1989-10-01

    The objective of the IGNITEX Project is to produce and control ignited plasmas for scientific study in the simplest and least expensive way possible. The original concept was proposed by both physics and engineering researchers along the following line of thought. Question: Is there any theoretically simple, compact and reliable way of achieving fusion ignition according to the results of the fusion research program for the last decades? Answer: Yes. An experiment to be carried out in an ohmically heated compact tokamak device with 20 T field on plasma axis. Question: Is there any practical way to carry out that experiment at low cost in the near term? Answer: Yes. Using a single-turn coil magnet system with homopolar power supplies.

  12. Equilibrium system analysis in a tokamak ignition experiment

    Energy Technology Data Exchange (ETDEWEB)

    Carrera, R.; Weldon, W.F.; Woodson, H.H.

    1989-10-01

    The objective of the IGNITEX Project is to produce and control ignited plasmas for scientific study in the simplest and least expensive way possible. The original concept was proposed by both physics and engineering researchers along the following line of thought. Question: Is there any theoretically simple, compact and reliable way of achieving fusion ignition according to the results of the fusion research program for the last decades Answer: Yes. An experiment to be carried out in an ohmically heated compact tokamak device with 20 T field on plasma axis. Question: Is there any practical way to carry out that experiment at low cost in the near term Answer: Yes. Using a single-turn coil magnet system with homopolar power supplies.

  13. Auto Body Repair 103, 203, 303.

    Science.gov (United States)

    Manitoba Dept. of Education, Winnipeg.

    As part of the high school vocational industrial program in Manitoba, this course has been designed to provide students with the foundation for a career in auto-body repair. The program introduces and provides opportunities for student skill development in the theories and techniques of tool and equipment operation, metallurgy and welding, damage…

  14. Mathematical model of three winding auto transformer

    International Nuclear Information System (INIS)

    Volcko, V.; Eleschova, Z.; Belan, A.; Janiga, P.

    2012-01-01

    This article deals with the design of mathematical model of three-winding auto transformer for steady state analyses. The article is focused on model simplicity for the purposes of the use in complex transmission systems and authenticity of the model taking into account different types of step-voltage regulator. (Authors)

  15. Auto Euroopa Liidus kallim / Sulev Oll

    Index Scriptorium Estoniae

    Oll, Sulev, 1964-

    2001-01-01

    Euroopa Liiduga liitumisel tuleb uue auto eest välja käia vähemalt 10 000 krooni rohkem, kuna plaanide kohaselt ei tohi liikmesriikides autode hinnaerinevused ületada 12%. Ilmunud ka: Delovõje Vedomosti, 28. märts 2001, lk. 7

  16. A Primary Talkk about Chinese Auto Parts

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    <正> Along with the completion of the second phase of the socialist modernization construction in 2000, China is starting to initiate the Tenth Five-Year Plan. 2001-2005 will be a key period during which China is supposed to build the third strategic objective It is also an extraordinary period for Chinese auto industry to bring in line with international practice.

  17. The Marketing Channels of China Auto Industry

    Institute of Scientific and Technical Information of China (English)

    our reporter

    2001-01-01

    <正> After the 1990’s, the multi-channel structure of sales has still existed although the market mechanism is playing a main role in Chinese auto marketing circulation. Now, the channels of automobile marketing in China are as follows: 1. Manufacturer-established marketing channels

  18. MICRO AUTO GASIFICATION SYSTEM: EMISSIONS CHARACTERIZATION

    Science.gov (United States)

    A compact, CONEX-housed waste to energy unit, Micro Auto Gasification System (MAGS), was characterized for air emissions from burning of military waste types. The MAGS unit is a dual chamber gasifier with a secondary diesel-fired combustor. Eight tests were conducted with multipl...

  19. Auto-correlograms and auto-regressive models of trace metal distributions in Cochin backwaters

    Digital Repository Service at National Institute of Oceanography (India)

    Jayalakshmy, K.V.; Sankaranarayanan, V.N.

    Auto-correlation technique has been applied to study fluctuations in concentration profiles of chemical species in Cochin Backwaters (Kerala, India). No stability in time can be detected for particulate Mn at all stations, for Fe at stations 1...

  20. Effect of Hydrogen Addition on Methane HCCI Engine Ignition Timing and Emissions Using a Multi-zone Model

    Science.gov (United States)

    Wang, Zi-han; Wang, Chun-mei; Tang, Hua-xin; Zuo, Cheng-ji; Xu, Hong-ming

    2009-06-01

    Ignition timing control is of great importance in homogeneous charge compression ignition engines. The effect of hydrogen addition on methane combustion was investigated using a CHEMKIN multi-zone model. Results show that hydrogen addition advances ignition timing and enhances peak pressure and temperature. A brief analysis of chemical kinetics of methane blending hydrogen is also performed in order to investigate the scope of its application, and the analysis suggests that OH radical plays an important role in the oxidation. Hydrogen addition increases NOx while decreasing HC and CO emissions. Exhaust gas recirculation (EGR) also advances ignition timing; however, its effects on emissions are generally the opposite. By adjusting the hydrogen addition and EGR rate, the ignition timing can be regulated with a low emission level. Investigation into zones suggests that NOx is mostly formed in core zones while HC and CO mostly originate in the crevice and the quench layer.

  1. Rational Thoughts on the Development of Chinese Auto Industry

    Institute of Scientific and Technical Information of China (English)

    Shao Qihui

    2004-01-01

    @@ In order to keep the steady, fast and sustainable development of auto industry, we should have an overall knowledge of the history and current situation of the world auto industry, and have a correct strategic planning and scientific measures towards the Chinese auto industry.

  2. 46 CFR 78.19-1 - Use of auto pilot.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Use of auto pilot. 78.19-1 Section 78.19-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS OPERATIONS Auto Pilot § 78.19-1 Use of auto pilot. Except as provided in 33 CFR 164.15, when the automatic pilot is used in— (a...

  3. 46 CFR 97.16-1 - Use of auto pilot.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Use of auto pilot. 97.16-1 Section 97.16-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS OPERATIONS Auto Pilot § 97.16-1 Use of auto pilot. Except as provided in 33 CFR 164.15, when the automatic pilot is used...

  4. 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)

  5. Ignition properties of nuclear grade activated carbons

    International Nuclear Information System (INIS)

    Freeman, W.P.; Hunt, J.R.; Kovach, J.L.

    1983-01-01

    The ignition property of new activated carbons used in air cleaning systems of nuclear facilities has been evaluated in the past, however very little information has been generated on the behavior of aged, weathered carbons which have been exposed to normal nuclear facility environment. Additionally the standard procedure for evaluation of ignition temperature of carbon is performed under very different conditions than those used in the design of nuclear air cleaning systems. Data were generated evaluating the ageing of activated carbons and comparing their CH 3 131 I removal histories to their ignition temperatures. A series of tests were performed on samples from one nuclear power reactor versus use time, a second series evaluated samples from several plants showing the variability of atmospheric effects. The ignition temperatures were evaluated simulating the conditions existing in nuclear air cleaning systems, such as velocity, bed depth, etc., to eliminate potential confusion resulting from artifically set current standard conditions

  6. Plasma igniter for internal-combustion engines

    Science.gov (United States)

    Breshears, R. R.; Fitzgerald, D. J.

    1978-01-01

    Hot ionized gas (plasma) ignites air/fuel mixture in internal combustion engines more effectively than spark. Electromagnetic forces propel plasma into combustion zone. Combustion rate is not limited by flame-front speed.

  7. Test plan for core drilling ignitability testing

    International Nuclear Information System (INIS)

    Witwer, K.S.

    1996-01-01

    The objective of this testing is to determine if ignition occurs while core drilling in a flammable gas environment. Drilling parameters are chosen so as to provide bounding conditions for the core sampling environment. If ignition does not occur under the conditions set forth in this test, then a satisfactory level of confidence will be obtained which would allow field operations under the normal drilling conditions

  8. Dynamic Regime of Ignition of Solid Propellant

    Directory of Open Access Journals (Sweden)

    Zolotorev Nikolay

    2016-01-01

    Full Text Available This article presents a dynamic regime of exposure of the radiant flux on the sample of gun-cotton. Obtained time the ignition of gun-cotton in the heating conditions of increasing heat flux in the range from 0.2 W/cm2 to 22 W/cm2. A comparison of the delay times of the ignition when heated variable and constant heat flux.

  9. The National Ignition Facility Project. Revision 1

    International Nuclear Information System (INIS)

    Paisner, J.A.; Campbell, E.M.; Hogan, W.J.

    1994-01-01

    The mission of the National Ignition Facility is to achieve ignition and gain in inertial confinement fusion targets in the laboratory. The facility will be used for defense applications such as weapons physics and weapons effects testing, and for civilian applications such as fusion energy development and fundamental studies of matter at high temperatures and densities. This paper reviews the design, schedule, and costs associated with the construction project

  10. Confinement scaling and ignition in tokamaks

    International Nuclear Information System (INIS)

    Perkins, F.W.; Sun, Y.C.

    1985-10-01

    A drift wave turbulence model is used to compute the scaling and magnitude of central electron temperature and confinement time of tokamak plasmas. The results are in accord with experiment. Application to ignition experiments shows that high density (1 to 2) . 10 15 cm -3 , high field, B/sub T/ > 10 T, but low temperature T approx. 6 keV constitute the optimum path to ignition

  11. Physics parameter space of tokamak ignition devices

    International Nuclear Information System (INIS)

    Selcow, E.C.; Peng, Y.K.M.; Uckan, N.A.; Houlberg, W.A.

    1985-01-01

    This paper describes the results of a study to explore the physics parameter space of tokamak ignition experiments. A new physics systems code has been developed to perform the study. This code performs a global plasma analysis using steady-state, two-fluid, energy-transport models. In this paper, we discuss the models used in the code and their application to the analysis of compact ignition experiments. 8 refs., 8 figs., 1 tab

  12. Self-Image Development: A Chicano Enfasis. Self-Programmed Counseling and Self-Programmed Control. Instructor's Guide = Desarrollo de la Imagen Propia: Enfasis en el Chicano. Sistema de Consejo y Control Auto-Programado. Manuel del Profesor.

    Science.gov (United States)

    Mireles, S. Raymond

    Self-Programmed Counseling, the instructor's guidance, and Self-Programmed Control (SPC), the student's response, was initially developed by Title III Project USTED (United Students and Teachers for Educational Development) for Mexican American students on academic probation to use on a non-credit, special group counseling basis. As part of a…

  13. Plasma transport in a compact ignition tokamak

    International Nuclear Information System (INIS)

    Singer, C.E.; Ku, L.P; Bateman, G.

    1987-02-01

    Nominal predicted plasma conditions in a compact ignition tokamak are illustrated by transport simulations using experimentally calibrated plasma transport models. The range of uncertainty in these predictions is explored by using various models which have given almost equally good fits to experimental data. Using a transport model which best fits the data, thermonuclear ignition occurs in a Compact Ignition Tokamak design with major radius 1.32 m, plasma half-width 0.43 m, elongation 2.0, and toroidal field and plasma current ramped in six seconds from 1.7 to 10.4 T and 0.7 to 10 MA, respectively. Ignition is facilitated by 20 MW of heating deposited off the magnetic axis near the 3 He minority cyclotron resonance layer. Under these conditions, sawtooth oscillations are small and have little impact on ignition. Tritium inventory is minimized by preconditioning most discharges with deuterium. Tritium is injected, in large frozen pellets, only after minority resonance preheating. Variations of the transport model, impurity influx, heating profile, and pellet ablation rates, have a large effect on ignition and on the maximum beta that can be achieved

  14. Does charge transfer correlate with ignition probability?

    International Nuclear Information System (INIS)

    Holdstock, Paul

    2008-01-01

    Flammable or explosive atmospheres exist in many industrial environments. The risk of ignition caused by electrostatic discharges is very real and there has been extensive study of the incendiary nature of sparks and brush discharges. It is clear that in order to ignite a gas, an amount of energy needs to be delivered to a certain volume of gas within a comparatively short time. It is difficult to measure the energy released in an electrostatic discharge directly, but it is possible to approximate the energy in a spark generated from a well defined electrical circuit. The spark energy required to ignite a gas, vapour or dust cloud can be determined by passing such sparks through them. There is a relationship between energy and charge in a capacitive circuit and so it is possible to predict whether or not a spark discharge will cause an ignition by measuring the charge transferred in the spark. Brush discharges are in many ways less well defined than sparks. Nevertheless, some work has been done that has established a relationship between charge transferred in brush discharges and the probability of igniting a flammable atmosphere. The question posed by this paper concerns whether such a relationship holds true in all circumstances and if there is a universal correlation between charge transfer and ignition probability. Data is presented on discharges from textile materials that go some way to answering this question.

  15. TOPICAL REVIEW: Plasma assisted ignition and combustion

    Science.gov (United States)

    Starikovskaia, S. M.

    2006-08-01

    In recent decades particular interest in applications of nonequilibrium plasma for the problems of plasma-assisted ignition and plasma-assisted combustion has been observed. A great amount of experimental data has been accumulated during this period which provided the grounds for using low temperature plasma of nonequilibrium gas discharges for a number of applications at conditions of high speed flows and also at conditions similar to automotive engines. The paper is aimed at reviewing the data obtained and discusses their treatment. Basic possibilities of low temperature plasma to ignite gas mixtures are evaluated and historical references highlighting pioneering works in the area are presented. The first part of the review discusses plasmas applied to plasma-assisted ignition and combustion. The paper pays special attention to experimental and theoretical analysis of some plasma parameters, such as reduced electric field, electron density and energy branching for different gas discharges. Streamers, pulsed nanosecond discharges, dielectric barrier discharges, radio frequency discharges and atmospheric pressure glow discharges are considered. The second part depicts applications of discharges to reduce the ignition delay time of combustible mixtures, to ignite transonic and supersonic flows, to intensify ignition and to sustain combustion of lean mixtures. The results obtained by different authors are cited, and ways of numerical modelling are discussed. Finally, the paper draws some conclusions on the main achievements and prospects of future investigations in the field.

  16. Bone marrow function. I. Peripheral T cells are responsible for the increased auto-antiidiotype response of older mice

    International Nuclear Information System (INIS)

    Kim, Y.T.; Goidl, E.A.; Samarut, C.; Weksler, M.E.; Thorbecke, G.J.; Siskind, G.W.

    1985-01-01

    After immunization with trinitrophenyl (TNP)-Ficoll, mice produced both anti-TNP antibodies and auto-anti-idiotype (auto-anti-Id) antibodies specific for the anti-TNP antibody. Older animals produced more auto-anti-Id than did young animals. When mice were exposed to a normally lethal dose of irradiation while their bone marrow (BM) was partially shielded, they survived and slowly (6 wk) regained immune function, as indicated by the number of nucleated cells in their spleen and the in vitro primary plaque-forming cell (PFC) response of their spleen cells to TNP-treated aminoethylated polyacrylamide beads. Recovery is presumably the result of repopulation of the peripheral lymphoid system by cells originating in the BM. By enzyme-linked immunosorbent assay (ELISA), and by hapten-augmentable PFC assay, the authors show that, after recovery from irradiation with their BM shielded, old animals produce low auto-anti-Id responses, like those of young animals. The transfer of splenic T cells into mice irradiated with their BM shielded provided evidence that the magnitude of the auto-anti-Id response is controlled by the peripheral T cells. Thus, mice that received splenic T cells from aged donors produced high levels of auto-anti-Id while those that received splenic T cells from young donors produce low levels of auto-anti-Id

  17. The National Ignition Facility 2007 laser performance status

    Energy Technology Data Exchange (ETDEWEB)

    Haynam, C A; Sacks, R A; Wegner, P J; Bowers, M W; Dixit, S N; Erbert, G V; Heestand, G M; Henesian, M A; Hermann, M R; Jancaitis, K S; Manes, K R; Marshall, C D; Mehta, N C; Menapace, J; Nostrand, M C; Orth, C D; Shaw, M J; Sutton, S B; Williams, W H; Widmayer, C C [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA, 94550 (United States)], E-mail: haynam1@llnl.gov (and others)

    2008-05-15

    The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory contains a 192-beam 3.6 MJ neodymium glass laser that is frequency converted to 351nm light. It has been designed to support high energy density science (HEDS), including the demonstration of fusion ignition through Inertial Confinement. To meet this goal, laser design criteria include the ability to generate pulses of up to 1.8-MJ total energy at 351nm, with peak power of 500 TW and precisely-controlled temporal pulse shapes spanning two orders of magnitude. The focal spot fluence distribution of these pulses is conditioned, through a combination of special optics in the 1{omega} (1053 nm) portion of the laser (continuous phase plates), smoothing by spectral dispersion (SSD), and the overlapping of multiple beams with orthogonal polarization (polarization smoothing). In 2006 and 2007, a series of measurements were performed on the NIF laser, at both 1{omega} and 3{omega} (351 nm). When scaled to full 192-beam operation, these results lend confidence to the claim that NIF will meet its laser performance design criteria and that it will be able to simultaneously deliver the temporal pulse shaping, focal spot conditioning, peak power, shot-to-shot reproducibility, and power balance requirements of indirect-drive fusion ignition campaigns. We discuss the plans and status of NIF's commissioning, and the nature and results of these measurement campaigns.

  18. Homogeneous Charge Compression Ignition Combustion: Challenges and Proposed Solutions

    Directory of Open Access Journals (Sweden)

    Mohammad Izadi Najafabadi

    2013-01-01

    Full Text Available Engine and car manufacturers are experiencing the demand concerning fuel efficiency and low emissions from both consumers and governments. Homogeneous charge compression ignition (HCCI is an alternative combustion technology that is cleaner and more efficient than the other types of combustion. Although the thermal efficiency and NOx emission of HCCI engine are greater in comparison with traditional engines, HCCI combustion has several main difficulties such as controlling of ignition timing, limited power output, and weak cold-start capability. In this study a literature review on HCCI engine has been performed and HCCI challenges and proposed solutions have been investigated from the point view of Ignition Timing that is the main problem of this engine. HCCI challenges are investigated by many IC engine researchers during the last decade, but practical solutions have not been presented for a fully HCCI engine. Some of the solutions are slow response time and some of them are technically difficult to implement. So it seems that fully HCCI engine needs more investigation to meet its mass-production and the future research and application should be considered as part of an effort to achieve low-temperature combustion in a wide range of operating conditions in an IC engine.

  19. Numerical simulations of turbulent jet ignition and combustion

    Science.gov (United States)

    Validi, Abdoulahad; Irannejad, Abolfazl; Jaberi, Farhad

    2013-11-01

    The ignition and combustion of a homogeneous lean hydrogen-air mixture by a turbulent jet flow of hot combustion products injected into a colder gas mixture are studied by a high fidelity numerical model. Turbulent jet ignition can be considered as an efficient method for starting and controlling the reaction in homogeneously charged combustion systems used in advanced internal combustion and gas turbine engines. In this work, we study in details the physics of turbulent jet ignition in a fundamental flow configuration. The flow and combustion are modeled with the hybrid large eddy simulation/filtered mass density function (LES/FMDF) approach, in which the filtered form the compressible Navier-Stokes equations are solved with a high-order finite difference scheme for the turbulent velocity and the FMDF transport equations are solved with a Lagrangian stochastic method to obtain the scalar (temperature and species mass fractions) field. The hydrogen oxidation is described by a detailed reaction mechanism with 37 elementary reactions and 9 species.

  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. National Ignition Facility Configuration Management Plan

    International Nuclear Information System (INIS)

    Cabral, S G; Moore, T L

    2002-01-01

    This Configuration Management Plan (CMP) describes the technical and administrative management process for controlling the National Ignition Facility (NIF) Project configuration. The complexity of the NIF Project (i.e., participation by multiple national laboratories and subcontractors involved in the development, fabrication, installation, and testing of NIF hardware and software, as well as construction and testing of Project facilities) requires implementation of the comprehensive configuration management program defined in this plan. A logical schematic illustrating how the plan functions is provided in Figure 1. A summary of the process is provided in Section 4.0, Configuration Change Control. Detailed procedures that make up the overall process are referenced. This CMP is consistent with guidance for managing a project's configuration provided in Department of Energy (DOE) Order 430.1, Guide PMG 10, ''Project Execution and Engineering Management Planning''. Configuration management is a formal discipline comprised of the following four elements: (1) Identification--defines the functional and physical characteristics of a Project and uniquely identifies the defining requirements. This includes selection of components of the end product(s) subject to control and selection of the documents that define the project and components. (2) Change management--provides a systematic method for managing changes to the project and its physical and functional configuration to ensure that all changes are properly identified, assessed, reviewed, approved, implemented, tested, and documented. (3) Data management--ensures that necessary information on the project and its end product(s) is systematically recorded and disseminated for decision-making and other uses. Identifies, stores and controls, tracks status, retrieves, and distributes documents. (4) Assessments and validation--ensures that the planned configuration requirements match actual physical configurations and

  2. Auto-optimisation for three-dimensional conformal radiotherapy of nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Wu, V.W.C.; Kwong, D.W.L.; Sham, J.S.T.; Mui, A.W.L.

    2003-01-01

    Purpose: The purpose of this study was to evaluate the application of auto-optimisation in the treatment planning of three-dimensional conformal radiotherapy (3DCRT) of nasopharyngeal carcinoma (NPC). Methods: Twenty-nine NPC patients were planned by both forward planning and auto-optimisation methods. The forward plans, which consisted of three coplanar facial fields, were produced according to the routine planning criteria. The auto-optimised plans, which consisted of 5-15 (median 9) fields, were generated by the planning system after prescribing the dose requirements and the importance weightings of the planning target volume and organs at risk. Plans produced by the two planning methods were compared by the dose volume histogram, tumour control probability (TCP), conformity index and normal tissue complication probability (NTCP). Results: The auto-optimised plans reduced the average planner's time by over 35 min. It demonstrated better TCP and conformity index than the forward plans (P=0.03 and 0.04, respectively). Besides, the parotid gland and temporo-mandibular (TM) joint were better spared with the mean dose reduction of 31.8 and 17.7%, respectively. The slight trade off was the mild dose increase in spinal cord and brain stem with their maximum doses remaining within the tolerance limits. Conclusions: The findings demonstrated the potentials of auto-optimisation for improving target dose and parotid sparing in the 3DCRT of NPC with saving of the planner's time

  3. Auto-optimisation for three-dimensional conformal radiotherapy of nasopharyngeal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Wu, V.W.C. E-mail: orvinwu@polyu.edu.hk; Kwong, D.W.L.; Sham, J.S.T.; Mui, A.W.L

    2003-08-01

    Purpose: The purpose of this study was to evaluate the application of auto-optimisation in the treatment planning of three-dimensional conformal radiotherapy (3DCRT) of nasopharyngeal carcinoma (NPC). Methods: Twenty-nine NPC patients were planned by both forward planning and auto-optimisation methods. The forward plans, which consisted of three coplanar facial fields, were produced according to the routine planning criteria. The auto-optimised plans, which consisted of 5-15 (median 9) fields, were generated by the planning system after prescribing the dose requirements and the importance weightings of the planning target volume and organs at risk. Plans produced by the two planning methods were compared by the dose volume histogram, tumour control probability (TCP), conformity index and normal tissue complication probability (NTCP). Results: The auto-optimised plans reduced the average planner's time by over 35 min. It demonstrated better TCP and conformity index than the forward plans (P=0.03 and 0.04, respectively). Besides, the parotid gland and temporo-mandibular (TM) joint were better spared with the mean dose reduction of 31.8 and 17.7%, respectively. The slight trade off was the mild dose increase in spinal cord and brain stem with their maximum doses remaining within the tolerance limits. Conclusions: The findings demonstrated the potentials of auto-optimisation for improving target dose and parotid sparing in the 3DCRT of NPC with saving of the planner's time.

  4. National Ignition Facility Project Site Safety Program

    International Nuclear Information System (INIS)

    Dun, C

    2003-01-01

    This Safety Program for the National Ignition Facility (NIF) presents safety protocols and requirements that management and workers shall follow to assure a safe and healthful work environment during activities performed on the NIF Project site. The NIF Project Site Safety Program (NPSSP) requires that activities at the NIF Project site be performed in accordance with the ''LLNL ES and H Manual'' and the augmented set of controls and processes described in this NIF Project Site Safety Program. Specifically, this document: (1) Defines the fundamental NIF site safety philosophy. (2) Defines the areas covered by this safety program (see Appendix B). (3) Identifies management roles and responsibilities. (4) Defines core safety management processes. (5) Identifies NIF site-specific safety requirements. This NPSSP sets forth the responsibilities, requirements, rules, policies, and regulations for workers involved in work activities performed on the NIF Project site. Workers are required to implement measures to create a universal awareness that promotes safe practice at the work site and will achieve NIF management objectives in preventing accidents and illnesses. ES and H requirements are consistent with the ''LLNL ES and H Manual''. This NPSSP and implementing procedures (e.g., Management Walkabout, special work procedures, etc.,) are a comprehensive safety program that applies to NIF workers on the NIF Project site. The NIF Project site includes the B581/B681 site and support areas shown in Appendix B

  5. 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

  6. A Model based Examination of Conditions for Ignition of Turbidity Currents on Slopes

    Science.gov (United States)

    Mehta, A. J.; Krishna, G.

    2009-12-01

    Turbidity currents form a major mechanism for the movement of sediment in the natural environment. Self-accelerating turbidity currents over continental slopes are of considerable scientific and engineering interest due to their role as agents for submarine sediment transportation from the shelf to the seabed. Such currents are called ignitive provided they eventually reach a catastrophic state as acceleration results in high sediment loads due to erosion of the sloping bed. A numerical model, which treats the fluid and the particles as two separate phases, is applied to investigate the effects of particle size, initial flow friction velocity and mild bed slope on the ignitive condition. Laboratory experimental data have been included as part of the analysis for qualitative comparison purposes. Ignition for the smallest of the three selected sizes (0.21mm) of medium sand typical of Florida beaches was found to depend on the initial conditions at the head of the slope as determined by the pressure gradient. Bed slope seemed to be of secondary importance. For the two sands with larger grain sizes (0.28mm and 0.35mm) the slope was found to play a more important role when compared to the initial pressure gradient. For a given pressure gradient, increasing the slope increased the likelihood of self-acceleration. It is concluded that in general ignition cannot be defined merely in terms of positive values of the velocity gradient and the sediment flux gradient along the slope. Depending on particle size the initial pressure gradient can also play a role. For the selected initial conditions (grain size, pressure gradient and bed slope), out of the 54 combinations tested, all except three satisfied the Knapp-Bagnold criterion for auto-suspension irrespective of whether the turbid current was ignitive or non-ignitive. In all 54 cases the current was found to erode the bed. Further use of the model will require accommodation of wider ranges of sediment size and bed density

  7. Ignition delay times of Gasoline Distillation Cuts measured with Ignition Quality Tester

    KAUST Repository

    Naser, Nimal

    2017-04-21

    Tailoring fuel properties to maximize the efficiency of internal combustion engines is a way towards achieving cleaner combustion systems. In this work, the ignition properties of various gasoline fuel distillation cuts are analyzed to better understand fuel properties of the full boiling range fuel. An advanced distillation column (ADC) provides a more realistic representation of volatility characteristics, which can be modeled using equilibrium thermodynamic methods. The temperature reported is that of the liquid, as opposed to the vapor temperature in conventional ASTM D86 distillation standard. Various FACE (fuels for advanced combustion engines) gasolines were distilled and various cuts were obtained. The separated fractions were then tested in an ignition quality tester (IQT) to see the effect of chemical composition of different fractions on their ignition delay time. Fuels with lower aromatic content showed decreasing ignition delay time with increasing boiling point (i.e., molecular weight). However, fuels with higher aromatic content showed an initial decrease in ignition delay time with increasing boiling point, followed by drastic increase in ignition delay time due to fractions containing aromatics. This study also provides an understanding on contribution of different fractions to the ignition delay time of the fuel, which provides insights into fuel stratification utilized in gasoline compression ignition (GCI) engines to tailor heat release rates.

  8. Recent progress in ignition fusion research on the National Ignition Facility

    International Nuclear Information System (INIS)

    Leeper, Ramon J.

    2011-01-01

    This paper will review the ignition fusion research program that is currently being carried out on the National Ignition Facility (NIF) located at Lawrence Livermore National Laboratory. This work is being conducted under the auspices of the National Ignition Campaign (NIC) that is a broad collaboration of national laboratories and universities that together have developed a detailed research plan whose goal is ignition in the laboratory. The paper will begin with a description of the NIF facility and associated experimental facilities. The paper will then focus on the ignition target and hohlraum designs that will be tested in the first ignition attempts on NIF. The next topic to be introduced will be a description of the diagnostic suite that has been developed for the initial ignition experiments on NIF. The paper will then describe the experimental results that were obtained in experiments conducted during the fall of 2009 on NIF. Finally, the paper will end with a description of the detailed experimental plans that have been developed for the first ignition campaign that will begin later this year. (author)

  9. Adrenaline auto-injectors for the treatment of anaphylaxis with and without cardiovascular collapse in the community.

    Science.gov (United States)

    Sheikh, Aziz; Simons, F Estelle R; Barbour, Victoria; Worth, Allison

    2012-08-15

    Anaphylaxis is a serious hypersensitivity reaction that is rapid in onset and may cause death. Adrenaline (epinephrine) auto-injectors are recommended as the initial, potentially life-saving treatment of choice for anaphylaxis in the community, but they are not universally available and have limitations in their use. To assess the effectiveness of adrenaline (epinephrine) auto-injectors in relieving respiratory, cardiovascular, and other symptoms during episodes of anaphylaxis that occur in the community. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 1), MEDLINE (Ovid SP) (1950 to January 2012), EMBASE (Ovid SP) (1980 to January 2012 ), CINAHL (EBSCO host) (1982 to January 2012 ), AMED (EBSCO host) (1985 to January 2012 ), LILACS, (BIREME) (1980 to January 2012 ), ISI Web of Science (1950 to January 2012 ). We adapted our search terms for other databases. We also searched websites listing on-going trials: the World Health Organization International Clinical Trials Registry Platform, the UK Clinical Research Network Study Portfolio, and the meta Register of Controlled Trials; and contacted pharmaceutical companies who manufacture adrenaline auto-injectors in an attempt to locate unpublished material. Randomized and quasi-randomized controlled trials comparing auto-injector administration of adrenaline with any control including no intervention, placebo, or other adrenergic agonists were eligible for inclusion. Two authors independently assessed articles for inclusion. None of the 1328 studies that were identified satisfied the inclusion criteria. Based on this review, we cannot make any new recommendations on the effectiveness of adrenaline auto-injectors for the treatment of anaphylaxis. Although randomized, double-blind, placebo-controlled clinical trials of high methodological quality are necessary to define the true extent of benefits from the administration of adrenaline in anaphylaxis via an auto

  10. AutoCAD-To-GIFTS Translator Program

    Science.gov (United States)

    Jones, Andrew

    1989-01-01

    AutoCAD-to-GIFTS translator program, ACTOG, developed to facilitate quick generation of small finite-element models using CASA/GIFTS finite-element modeling program. Reads geometric data of drawing from Data Exchange File (DXF) used in AutoCAD and other PC-based drafting programs. Geometric entities recognized by ACTOG include points, lines, arcs, solids, three-dimensional lines, and three-dimensional faces. From this information, ACTOG creates GIFTS SRC file, which then reads into GIFTS preprocessor BULKM or modified and reads into EDITM to create finite-element model. SRC file used as is or edited for any number of uses. Written in Microsoft Quick-Basic (Version 2.0).

  11. Gamma ray auto absorption correction evaluation methodology

    International Nuclear Information System (INIS)

    Gugiu, Daniela; Roth, Csaba; Ghinescu, Alecse

    2010-01-01

    Neutron activation analysis (NAA) is a well established nuclear technique, suited to investigate the microstructural or elemental composition and can be applied to studies of a large variety of samples. The work with large samples involves, beside the development of large irradiation devices with well know neutron field characteristics, the knowledge of perturbing phenomena and adequate evaluation of correction factors like: neutron self shielding, extended source correction, gamma ray auto absorption. The objective of the works presented in this paper is to validate an appropriate methodology for gamma ray auto absorption correction evaluation for large inhomogeneous samples. For this purpose a benchmark experiment has been defined - a simple gamma ray transmission experiment, easy to be reproduced. The gamma ray attenuation in pottery samples has been measured and computed using MCNP5 code. The results show a good agreement between the computed and measured values, proving that the proposed methodology is able to evaluate the correction factors. (authors)

  12. Anti-pentraxin 3 auto-antibodies might be protective in lupus nephritis: a large cohort study.

    Science.gov (United States)

    Yuan, Mo; Tan, Ying; Pang, Yun; Li, Yong-Zhe; Song, Yan; Yu, Feng; Zhao, Ming-Hui

    2017-11-01

    Anti-pentraxin 3 (PTX3) auto-antibodies were found to be associated with the absence of renal involvement in systemic lupus erythematosus (SLE). This study is to investigate the prevalence of anti-PTX3 auto-antibodies and their clinical significance based on a large Chinese lupus nephritis cohort. One hundred and ninety-six active lupus nephritis patients, 150 SLE patients without clinical renal involvement, and 100 healthy controls were enrolled. Serum anti-PTX3 auto-antibodies and PTX3 levels were screened by enzyme-linked immunosorbent assay (ELISA). The associations between anti-PTX3 auto-antibodies and clinicopathological parameters in lupus nephritis were further analyzed. Anti-PTX3 auto-antibodies were less prevalent in active lupus nephritis patients compared with SLE without renal involvement (19.4% (38/196) versus 40.7% (61/150), p auto-antibodies were negatively correlated with proteinuria in lupus nephritis (r = -.143, p = .047). The levels of proteinuria, serum creatinine, and the prevalence of thrombotic microangiopathy were significantly higher in patients with higher PTX3 levels (≥3.207 ng/ml) and without anti-PTX3 auto-antibodies compared with patients with lower PTX3 levels (auto-antibodies (4.79 (3.39-8.28) versus 3.95 (1.78-7.0), p = .03; 168.84 ± 153.63 versus 101.44 ± 47.36, p = .01; 34.1% (14/41) versus 0% (0/9), p = .04; respectively). Anti-PTX3 auto-antibodies were less prevalent in active lupus nephritis patients compared with SLE without renal involvement and associated with less severe renal damage, especially with the combined evaluation of serum PTX3 levels.

  13. Flipped-Adversarial AutoEncoders

    OpenAIRE

    Zhang, Jiyi; Dang, Hung; Lee, Hwee Kuan; Chang, Ee-Chien

    2018-01-01

    We propose a flipped-Adversarial AutoEncoder (FAAE) that simultaneously trains a generative model G that maps an arbitrary latent code distribution to a data distribution and an encoder E that embodies an "inverse mapping" that encodes a data sample into a latent code vector. Unlike previous hybrid approaches that leverage adversarial training criterion in constructing autoencoders, FAAE minimizes re-encoding errors in the latent space and exploits adversarial criterion in the data space. Exp...

  14. El auto de fe de 1606

    Directory of Open Access Journals (Sweden)

    María Isabel Pérez de Colosía Rodríguez

    1994-01-01

    Full Text Available La relación del auto de fe de 1606, está dividida en los siguientes siete apartados: Relajados en persona, Relajados en estatua, Reconciliados por la secta de Mahoma, Reconciliados por la ley de Moisés, Reconciliados por la secta Luterana, Penintenciados con abjuración de behementi y Penitenciados con abjuración de levi.

  15. Antiproton fast ignition for inertial confinement fusion

    International Nuclear Information System (INIS)

    Perkins, L.J.

    1999-01-01

    With 180 MJ/microg, antiprotons offer the highest stored energy per unit mass of any known entity. The use of antiprotons to promote fast ignition in an inertial confinement fusion (ICF) capsule and produce high target gains with only modest compression of the main fuel is investigated. Unlike standard fast ignition where the ignition energy is supplied by energetic, short pulse laser, the energy here is supplied through the ionization energy deposited when antiprotons annihilate at the center of a compressed fuel capsule. This can be considered in-situ fast ignition as it obviates the need for the external injection of the ignition energy. In the first of two candidate schemes, the antiproton package is delivered by a low-energy ion beam. In the second, autocatalytic scheme, the antiprotons are preemplaced at the center of the capsule prior to compression. In both schemes, the author estimates that ∼10 12 antiprotons are required to initiate fast ignition in a typical ICF capsule and show that incorporation of a thin, heavy metal shell is desirable to enhance energy deposition within the ignitor zone. In addition to eliminating the need for a second, energetic fast laser and vulnerable final optics, this scheme would achieve central ignition without reliance on laser channeling through halo plasma or Hohlraum debris. However, in addition to the practical difficulties of storage and manipulation of antiprotons at low energy, the other large uncertainty for the practicality of such a speculative scheme is the ultimate efficiency of antiproton production in an external, optimized facility. Estimates suggest that the electrical wall plug energy per pulse required for the separate production of the antiprotons is of the same order as that required for the conventional slow compression driver

  16. Ignition parameters and early flame kernel development of laser-ignited combustible gas mixtures

    International Nuclear Information System (INIS)

    Kopecek, H.; Wintner, E.; Ruedisser, D.; Iskra, K.; Neger, T.

    2002-01-01

    Full text: Laser induced breakdown of focused pulsed laser radiation, the subsequent plasma formation and thermalization offers a possibility of ignition of combustible gas mixtures free from electrode interferences, an arbitrary choice of the location within the medium and exact timing regardless of the degree of turbulence. The development and the decreasing costs of solid state laser technologies approach the pay-off for the higher complexity of such an ignition system due to several features unique to laser ignition. The feasability of laser ignition was demonstrated in an 1.5 MW(?) natural gas engine, and several investigations were performed to determine optimal ignition energies, focus shapes and laser wavelengths. The early flame kernel development was investigated by time resolved planar laser induced fluorescence of the OH-radical which occurs predominantly in the flame front. The flame front propagation showed typical features like toroidal initial flame development, flame front return and highly increased flame speed along the laser focus axis. (author)

  17. A study experiment of auto idle application in the excavator engine performance

    Energy Technology Data Exchange (ETDEWEB)

    Purwanto, Wawan, E-mail: wawan5527@gmail.com; Maksum, Hasan; Putra, Dwi Sudarno, E-mail: dwisudarnoputra@ft.unp.ac.id; Wahyudi, Retno [State University of Padang, West Sumatera (Indonesia); Azmi, Meri, E-mail: meriazmi@gmail.com [State Polytechnic of Padang, West Sumatera (Indonesia)

    2016-03-29

    The purpose of this study was to analyze the effect of applying auto idle to excavator engine performance, such as machine unitization and fuel consumption in Excavator. Steps to be done are to modify the system JA 44 and 67 in Vehicle Electronic Control Unit (V-ECU). The modifications will be obtained from the pattern of the engine speed. If the excavator attachment is not operated, the engine speed will return to the idle speed automatically. From the experiment results the auto idle reduces fuel consumption in excavator engine.

  18. Container code recognition in information auto collection system of container inspection

    International Nuclear Information System (INIS)

    Su Jianping; Chen Zhiqiang; Zhang Li; Gao Wenhuan; Kang Kejun

    2003-01-01

    Now custom needs electrical application and automatic detection. Container inspection should not only give the image of the goods, but also auto-attain container's code and weight. Its function and track control, information transfer make up the Information Auto Collection system of Container Inspection. Code Recognition is the point. The article is based on model match, the close property of character, and uses it to recognize. Base on checkout rule, design the adjustment arithmetic, form the whole recognition strategy. This strategy can achieve high recognition ratio and robust property

  19. Use of a single-zone thermodynamic model with detailed chemistry to study a natural gas fueled homogeneous charge compression ignition engine

    International Nuclear Information System (INIS)

    Zheng Junnian; Caton, Jerald A.

    2012-01-01

    Highlights: ► Auto-ignition characteristics of a natural gas fueled HCCI engine. ► Engine speed had the greatest effect on the auto-ignition process. ► Increases of C 2 H 6 or C 3 H 8 improved the auto-ignition process. ► Engine performance was not sensitive to small changes in C 2 H 6 or C 3 H 8 . ► Nitric oxides concentrations decreased as engine speed or EGR level was increased. - Abstract: A single zone thermodynamic model with detailed chemical kinetics was used to simulate a natural gas fueled homogeneous charge compression ignition (HCCI) engine. The model employed Chemkin and used chemical kinetics for natural gas with 53 species and 325 reactions. This simulation was used to complete analyses for a modified 0.4 L single cylinder engine. The engine possessed a compression ratio of 21.5:1, and had a bore and stroke of 86 and 75 mm, respectively. Several sets of parametric studies were completed to investigate the minimal initial temperature, engine performance, and nitric oxide emissions of HCCI engine operation. The results show significant changes in combustion characteristics with varying engine operating conditions. Effects of varying equivalence ratios (0.3–1.0), engine speeds (1000–4000 RPM), EGR (0–40%), and fuel compositions were determined and analyzed in detail. In particular, every 0.1 increase in equivalence ratio or 500 rpm increase in engine speed requires about a 5 K higher initial temperature for complete combustion, and leads to around 0.7 bar increase in IMEP.

  20. Vulnerability and self-perceived health status among light and heavy smokers: the relationship to short-term fear appeal tobacco control messages Vulnerabilidade e percepção de saúde auto-referida entre fumantes leves e pesados: a relação com mensagens anti-fumo voltadas para o apelo ao medo imediato

    Directory of Open Access Journals (Sweden)

    André Salem Szklo

    2009-07-01

    Full Text Available It is important to stimulate smokers to acquire some level of risk perception associated with their current behavior in order to motivate smoking cessation. The present article attempts to understand how the content of short-term fear appeal government tobacco messages may interact with different levels of daily cigarette consumption in order to affect smokers' vulnerabilities, expressed by self-perceived health status. A Poisson model was used to estimate the prevalence ratio of fair or poor self-perceived health status (FPHS according to daily cigarette consumption. We also calculated the proportions of smokers who stated that selected health warning pictures on cigarette packets encourage people to quit smoking, stratified by self-perceived health status and daily cigarette consumption. The proportion of smokers with FPHS was 25% higher among those who smoked > 20 cigarettes/day (p = 0.01. Among smokers with FPHS, heavy smokers showed the highest proportions of responses in favor of selected warning pictures most closely related to losses in ordinary daily living, such as shortness of breath and being bothered by cigarette addiction. Short-term loss-framed tobacco control messages seem to have raised awareness of vulnerability among heavier smokers.É importante incentivar os fumantes a adquirir algum nível de percepção do risco associado ao seu comportamento atual, para motivá-los a parar de fumar. O artigo procura elucidar em que medida o conteúdo do apelo ao medo imediato contido em mensagens anti-fumo nas campanhas governamentais pode interagir com o consumo diário de cigarros, no sentido de afetar as vulnerabilidades dos fumantes, expressas pela percepção de saúde auto-referida. Um modelo de Poisson foi utilizado para estimar a razão de prevalências de percepção de saúde auto-referida regular ou ruim, segundo consumo diário de cigarros. Calculou-se também a proporção de fumantes que afirmou que mensagens anti