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Low temperature magnetoresistive effects and coulomb blockade in La0 7Ca0 3MnO3 nanoparticles synthesis by auto Ignition method

Low temperature magnetoresistive effects and coulomb blockade in La0 7Ca0 3MnO3 nanoparticles synthesis by auto Ignition method

sized by citrate auto-ignition method and their electrical properties (resistivity) investigated. Below 35 K, in- crease in the resistivity values with the decrease in tem- perature is observed without magnetic field. Below 35 K charging energy was found to be sensitive to the applica- tion of a magnetic field, which could not be explained by the pure CB model. Charging effect dependence upon magnetic field was explained assuming that there exist good contacts between the neighboring nanoparticles due to alignment of the magnetic Mn spins at the sur- faces of the neighboring nanoparticles with the magnetic field. These contacts delocalize the charges to neighbor- ing nanoparticles.
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Engine Hot Spots: Modes of Auto-ignition and Reaction Propagation

Engine Hot Spots: Modes of Auto-ignition and Reaction Propagation

Figure 3 shows plots of  against  that define the peninsula within which detonations can develop from hot spot auto-ignitions, as well as the extent of other auto-ignition regimes. The peninsula, defined by its upper and lower limits of  u and  l , was constructed from the results of many simulations of separate hot spot auto-ignitions. The absence of turbulence was not unduly restrictive, as turbulence time scales can be about three orders of magnitude larger than the auto-ignition times. If a hotspot initiates a propagating flame, initially it will be laminar, with progressively increased wrinkling, length scales, and acceleration due to turbulence as it propagates [22]. As  is increased, more of the heat release is transferred into the acoustic front, to extend the range of  values that can support a developing detonation, as can be seen from the figure. This aspect is demonstrated by the simulation shown in Fig. 4 of [3], in which the developing strength of the acoustic front can be observed as it moves outwards, and develops into a detonation outside the hot spot.
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Interpretation of Auto-ignition Delay Times Measured in Different Rapid Compression Machines

Interpretation of Auto-ignition Delay Times Measured in Different Rapid Compression Machines

The diversity of the different RCMs has been advantageously utilised to increase our understanding of the departures of the RCMs from their ideal performance. It is emphasised that the performances of all the RCMs are those at the time that the data was submitted to the Consortium. They are no guide to their present performance at the different centres. Allowances have been made for the effects of reaction during compression and heat loss thereafter. At the higher temperatures, stronger auto- ignition occurs at reactive hotspots, reducing the overall Livengood-Wu integral. Considerations of
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A Dynamical Systems Analysis of Methanol-Air Auto-Ignition

A Dynamical Systems Analysis of Methanol-Air Auto-Ignition

The mathematical method presented here is very similar to that of the original work of Maas and Pope [4], and Lam and Goussis [9], but was developed independently of them, at around the same time [15]. The fundamental difference between this analysis, and that of Maas and Pope, is that this was developed in order to provide a new and alternative insight into chemically explosive systems. The expectation was that, in a chemically explosive system described by branching, only a small number of independent eigen-modes would dominate the solution trajectory. Low temperature chemical branching and high temperature recombination is of central importance in understanding auto-ignition, and can then be understood in terms of the development of these eigen-modes, rather than in terms of a numerical solution to a large system of coupled reaction equations. Dynamical systems analysis of auto- ignition is expected to provide a more intuitive explanation of chemical branching, propagation and equilibrium termination than conventional reaction path analysis (RPA) and/or sensitivity analysis (SA), which will be discussed in detail later.
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Experimental and Modelling Study of the Impacts of n-Butanol Blending on the Auto-Ignition Behaviour of Gasoline and its Surrogate at Low Temperatures

Experimental and Modelling Study of the Impacts of n-Butanol Blending on the Auto-Ignition Behaviour of Gasoline and its Surrogate at Low Temperatures

The anti-knock quality or auto-ignition resistance of fuels and fuel blends is also important with respect to the development of new technologies such as Homogeneous Charge Compression Ignition (HCCI), Reactivity Controlled Compression Ignition (RCCI) and Gasoline Compression Ignition (GCI) engines where ignition is largely controlled by the auto-ignition kinetics of the fuel. The goal of this study is therefore to provide an improved understanding of the impacts of n-butanol addition to gasoline (RON 95 and MON 86.6) on its auto-ignition properties at various blending ratios (10%, 20%, 40% and 85% vol n-butanol, referred to as B10, B20, B40 and B85 respectively here), as well as to a gasoline surrogate mixture, in order to facilitate the evaluation of a recent chemical
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AUTO IGNITION OFF ECO FRIENDLY VEHICLE

AUTO IGNITION OFF ECO FRIENDLY VEHICLE

Fig3: Simulation of 555 timer in Proteus. The idling session can vary according to the circumstances and can be altered manually through potentiometer. When the wheel lost its kinetic inertia and maintains static inertia for more than 30 seconds, the system turn off the ignition in order to save fuel and curb carbon emission.

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Investigation on outline of   Homogeneous charge compression ignition and its scope of development

Investigation on outline of Homogeneous charge compression ignition and its scope of development

HCCI engines are a promising technology that can help reduce some of our energy problems in the nearfuture. However, control remains a challenge because HCCI engines do not have a direct means to control the combustion timing. Many concepts to be consider various parameters like, compression ratio, intake/exhaust temperature, intake mass, intake air pressure, composition could be controlled. With the generation of different concept a CFD simulation will be carried out to study the effect of various parameters on engine performance. A few degrees of difference in intake temperature can have significant effects on combustion strength. By varying intake temperatures for individual cylinders, combustion could be controlled, and also based on design of HCCI engine on feasible results. For determine the design parameters at full load / part load conditions CFD package analysis with 3D model could be applied for improving of combustion system. Till today the success of HCCI development is tempered by challenges that must be overcome before it hits the primetime of production. Control of the combustion process over the wide range of operating conditions experienced in everyday driving is the greatest challenge, because unlike a conventional-ignition engine, HCCI's combustion is not controlled by precisely timed spark events. Ensuring auto ignition at extreme temperatures and in the thinner air of high altitudes are the tallest hurdles to overcome.
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A Review on Homogeneous Charge Compression Ignition Engine

A Review on Homogeneous Charge Compression Ignition Engine

Internal combustion (IC) engines are widely used in numerous applications throughout the world. A new mode of combustion is being sought in order to reduce the emissions levels from these engines: homogeneous charge compression ignition (HCCI) engine technology is a potential candidate. The HCCI technique is the process by which a homogeneous mixture of air and fuel is compressed until auto-ignition occurs near the end of the compression stroke, followed by a combustion process that is significantly faster than either Compression Ignition (CI) or Spark Ignition (SI) combustion. The major disadvantage of SI engines is its low efficiency at partial loads. The compression ratio in SI engines is limited by knock and can normally be limited in the range from 8 to 12 contributing to the low efficiency. Conventional diesel combustion, as a typical representation of CI combustion, operates at higher compression ratios than SI engines. In this type of engine, the air–fuel mixture auto-ignites as a consequence of piston compression instead of ignition by a spark plug. The processes which occur between the two moments when the liquid fuel leaves the injector nozzles and when the fuel starts to burn are complex and include droplet formation, collisions, breakup, evaporation and vapour diffusion. The rate of combustion is effectively limited by these processes. A part of the air and fuel will be premixed and burn fast, but for the larger fraction of the fuel, the time scale of evaporation, diffusion, etc. is larger than the chemical time scale. Therefore, the mixture can be divided into high fuel concentration regions and high temperature flame regions. In the high fuel concentration regions, a large amount of soot is formed because of the absence of O 2 . Some soot can be oxidized
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Investigation of Emission Parameters on HCCI Engine using Chemical Kinetics

Investigation of Emission Parameters on HCCI Engine using Chemical Kinetics

commercial sector for a long time. While spark ignition Engine, due to its low emissions at exhaust gives additional benefit for environmental issues because of homogeneous mixture fuel and air. In these new technology which combines these two types is called as Homogeneous Charge Compression Ignition as the name indicates, in this HCCI Engine technology has SI Engine characteristics at inlet and compression strokes and has CI Engine characteristics at combustion and exhaust strokes. This technology results us in getting higher fuel efficiency and low emissions. HCCI Engine can be accepted over conventional Engines because of its performance, durable, sustainable and economical. Homogeneous Charge Compression Ignition reduce throttling losses. It meets the standards that are to be followed for emissions. Any alternate fuels and the conventional fuels can be used for the operation. As expansion ratio is increased using HCCI Engine results in increased thermodynamic efficiency than the conventional Engine. Emission can be controlled without the application of EGR system. In HCCI at normal compression ratio only the auto-ignition occurs and load limit can be extended which reduce the residuals in the fuel mixture to achieve the starting temperature of compression, mode of combustion as they are to be maintained in limits.
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1x10 -9 moles/cc. The ignition delay times are

1x10 -9 moles/cc. The ignition delay times are

The goal of present study is to establish the understanding of auto ignition in premixed combustion system and to determine the relationship between auto ignition delay times and fuel compositions for various temperatures, pressures and equivalence ratios using chemical kinetic modeling. As computational capacity improves numerical simulations are becoming more attractive for combustion studies. Comprehensive detailed kinetic mechanisms have been compiled to fully describe the fundamental chemical processes involved in fuel oxidation .For example, Curran et al. [1,2] have developed comprehensive mechanisms to study the oxidation of n-heptane and iso-octane. The former mechanism comprised of 560 species and 2539 reactions, while the latter contains 857 species and 3606 reactions. These mechanisms were tested by comparing computed results with various experimental data from laboratory devices, and a reasonably good agreement was reported between the predicted and the measured results, implying that the reaction mechanisms represent correctly the imported reaction pathways and rates of oxidation for these fuels.
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A review on knock phenomena in CNG diesel dual fuel system

A review on knock phenomena in CNG diesel dual fuel system

The research into the knock phenomenon for dual fuel engine has been carried out over the years. Knock is due to an autoignition phenomenon dominated by chemical kinetic reactions of the premixed fuel-air system. Karim et al. [21] stated that the occurrence of knock was confined by a relatively weak mixture around 60-80% of the stoichiometric ratio. Their investigation into the effects of changes in various operating parameters such as intake temperature and the quantity and quality of pilot liquid fuel, while using various primary gaseous fuels (propane, methane and hydrogen) has proven that knock was observed mainly caused by autoignition of the gaseous fuel- air mixture in the neighbourhood of the ignition points originating from the small pilot liquid fuel sprays. For CNG-diesel dual fuel operation, the knock phenomena are widely associated with CNG- diesel combustion due to high pressure-rise rates with the auto-ignition of fuel during the premixed combustion stage. In part load cases, CNG-diesel combustion increase ignition delay time, reduce the burning rate and combustion duration compared to diesel [22]. These problems allow more time for flame propagation that resulting tendency to knock. Wannatong et al. [23] found that intake mixture temperature and amount of CNG supply plays important role in knock characteristic. The real case situation also been reported that dual fuel mode could cause an engine damage due to knock phenomenon [24]. Selim [25] claimed that the onset knock for dual fuel engine associated with a drop in thermal efficiency and output power. He also found that knock starts earlier when high compression ratio is used.
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Wireless Security For Bike Ignition Using Android Via Bluetooth

Wireless Security For Bike Ignition Using Android Via Bluetooth

This project is about the executed and created by an application of cellular telephone auto ignition framework by utilizing EmbededBlue 506 Bluetooth innovation. This security system works when the Bluetooth signal was sent from the mobile phone, the ignition can be done by the system although the car still in locked condition. This system also can ignite the car at anywhere and anytime in the distance range between 0- 10 meter radius. In addition, the equipment parts used are the Rabbit Core Module (RCM3200) with the Prototyping Board (RCM3100) which is the heart of the created framework, the EmbededBlue (eb506) and Mobile Phone as a communication gadget. The software is composed by using the Dynamic C which is then arranged and stacked into Rabbit Core Module (RCM 3200).
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A Full-Cycle 3 Dimensional Numerical Simulation of a Direct Injection Diesel Engine

A Full-Cycle 3 Dimensional Numerical Simulation of a Direct Injection Diesel Engine

The numerical models used are based on standard hydrocarbon auto-ignition mechanism combustion model developed by Cox, et al [10]; Fisch, et al [11]; Halstead, et al [13] for the simulation of gas/wall heat transfer, high temperature combustion, species transport, ignition, turbulent combustion, and pollutant formation of hydrocarbon fuel, air, and residual (exhaust) gas as discussed previously. Eddy Breakup model was developed as the combustion model with active turbulence controlled combustion model (based on Magnussen formulation). The reaction time scale in this model considered to calculate with by the local value of the ratio of the turbulence kinetic energy k and its dissipation rate ε . Zeldovich model was used as NO model and Kennedy-Hyroyasu-Magnussen as soot formation model.
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DEVELOPMENT OF AN AIR PREHEATER FOR HCCI IN SPARK IGNITION ENGINESUtpal Kaushik

DEVELOPMENT OF AN AIR PREHEATER FOR HCCI IN SPARK IGNITION ENGINESUtpal Kaushik

Diesel engines (CI engines) produce a lot of particulate matter (PM) and have NOx emissions comparable to gasoline engines. Moreover, the rather low exaust temperatures and the oxygen-rich environment make it difficult to achieve an effective after-treatment. This causes relatively high tailpipe emissions. The part load efficiency however is higher than for gasoline engines, this is mainly due to the lack of a throttle valve. The power control strategy of diesel engines relies on the amount of fuel injected into the combustion chamber. There is no need for a throttle valve so there are no pressure losses. Although a Diesel cycle has a lower theoretical efficiency at the same CR than an Otto cycle, the theoretical efficiency is higher due to the high CR which is needed for high in-cylinder temperatures to allow auto-ignition. These relative high efficiencies imply a lower fuel consumption and consequently lower CO2 emissions than with gasoline engines. It can be concluded that gasoline engines have relatively low emissions but a low efficiency (high CO2 emissions) and diesel engines have relatively high emissions but a high eficiency (low CO2 emissions).
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Hydrogen and natural gas comparison in diesel HCCI engines -a review

Hydrogen and natural gas comparison in diesel HCCI engines -a review

Hydrogen addition to the HCCI engine is one of the effective waysto control the ignition timing since hydrogen is able to reduce ignition delay time effectively. Furthermore, hydrogen can be produced from the exhaust gases of the engine itself using a reformer, which is called an“on-board hydrogen producer” [7,32]. As the amount of hydrogen was increased, auto-ignition delay time reduced accordingly while the in-cylinder peak pressure increased, ignition temperature reduced and indicated power increased [1]. The use of hydrogen addition does not involve high cost since it uses a lower-pressure fuel-injection system[30]. Hydrogen addition to a diesel engine will retard the heat release rate and delays the temperature rise. Furthermore, the addition of hydrogen is able to increase the engine efficiency by a significant margin[15,20]. By using a catalytic reforming aid in HCCI,the addition of hydrogen in natural gas HCCI engines helps in decreasing the need for high intake temperatures and also is a means of extending the lower limit of HCCI operations[39]. D. Exhaust Gas Recirculation (EGR)
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CLEAN COMBUSTION CONTROL IN A COMPRESSION IGNITION ENGINE

CLEAN COMBUSTION CONTROL IN A COMPRESSION IGNITION ENGINE

To investigate the suitability of fuel properties for LTC enabling, researchers have tested fuels with a broad range of ignition characteristics, fuel chemistry, and volatility in CI engines [10], [37], [38], [50]–[54]. In general, highly reactive fuels, such as diesel, are better suited for LTC under low load conditions [35]. If fuels with high auto-ignition resistance are employed, the low load LTC operation is challenged by the combustion stability and thermal efficiency penalties [37]. On the contrary, the fuels with a lower reactivity are suitable for high load operation under premixed LTC conditions, while the highly reactive fuels can undergo premature ignition [38], [54]. The overall conclusion from the studies of fuel property effect on CI LTC is that a dynamic modification of fuel reactivity may be necessary for a stable operation over a wide engine operating range [10], [37], [53].
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Kinetic Characteristics of Ignition Dispersed Condensed Substance Single Heated to a High Temperature of the Particles

Kinetic Characteristics of Ignition Dispersed Condensed Substance Single Heated to a High Temperature of the Particles

The experimental investigations of ignition for solid CS by the single steel particle warmed to high temperatures was held used the plant according the methods [5]. Analysis and generalization of experimental data [3, 5, 7,8] on dependence of ignition delay time on initial temperature of heating source allow formulating an important statement regulating experimental conditions for determination of kinetic parameters. It is reasonable to conduct an experiment at the maximum possible initial temperature (T p ) of the particle (source of energy) for ensuring minimal errors of ignition delay time
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Numerical Simulation on the Ignition Characteristics of the Inner Hole Surface of Perforated Propellant Grains

Numerical Simulation on the Ignition Characteristics of the Inner Hole Surface of Perforated Propellant Grains

During the flow of ignition flame in the hole, heat transfer takes place between the ignition gases and the wall. The heat transfer includes thermal radiation and convection as well as heat conduction in propellant. The propellant materials are heated to decompose and start burning under certain temperature. In order to simplify calculation, the following assumptions should be set up:

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ANALYSIS ON COMBUSTION OF A PRIMARY REFERENCE FUEL

ANALYSIS ON COMBUSTION OF A PRIMARY REFERENCE FUEL

reactor. The GRI 3.0 mechanism constructed using 53 species and 325 reactions have been used for the analysis purpose. The software used for the analysis is COMSOL. The combustion characteristics such as pressure rise, formation of species, and ignition delay characteristics were studied in Homogeneous Charge compression ignition engine.

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Effect of CaO Addition on the Ignition Resistance of Mg Al Alloys

Effect of CaO Addition on the Ignition Resistance of Mg Al Alloys

CaO added AZ91 Mg alloy was extinguished. However, the fire of AZ91 Mg alloy continuously propagated by self- heating. The behavior of the ignition by torch was discussed from AES results as shown in Fig. 10. Figure 10 shows the AES depth profile sputtered form the surface of diecastings. In diecastings of AZ91 Mg alloy, it was confirmed that there was a thick MgO oxide layer on the surface because the concentration of Mg and O were constant for sputtering time. In diecastings of 0.3 mass%CaO added AZ91 Mg alloy, there was the thin oxide layers mixed with MgO and CaO. The mixed MgO and CaO oxide layer, generated by CaO, exhibits protective behavior below about, while weight gain by oxidation is accelerated with respect to temperature above 773 K because of porous MgO surface oxide film at high temperature.
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