Results 191 to 200 of about 45,698 (239)
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Nature Photonics, 2008
The pollutant emissions and high-energy consumption of combustion engines using conventional spark plugs have long been serious environmental problems. Now, it has been demonstrated that lasers can provide a feasible green alternative. Duncan Graham-Rowe reports.
Duncan Graham-Rowe, Rachel Won
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The pollutant emissions and high-energy consumption of combustion engines using conventional spark plugs have long been serious environmental problems. Now, it has been demonstrated that lasers can provide a feasible green alternative. Duncan Graham-Rowe reports.
Duncan Graham-Rowe, Rachel Won
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Laser ignition @ two wavelengths?
CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference, 2009The reduction of pollutant emissions and energy consumption represents a central objective in the improvement of internal combustion engines. This ambitious goal can be achieved by a clear optimization of combustion processes as well as ignition mechanisms.
S. Gross +4 more
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Minimum ignition energy for laser spark ignition
Proceedings of the Combustion Institute, 2005Abstract Combustion ignition by electrical sparks and nonresonant laser sparks is preceded by breakdown, electron heating, relaxation of internal plasma energy, shock wave generation and propagation, and subsonic flows. Measurements and model calculations of these processes (which occur over times of 10 −12 –10 −1 s) in laser sparks show that the ...
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Laser ignition of explosives: Effects of laser wavelength on the threshold ignition energy
Journal of Energetic Materials, 1994Abstract A method, based on a tunable 180 W CW CO2-laser (9–11 μm), for measuring the effect of laser wavelength, and hence optical absorbance coefficient, on the threshold ignition energy of explosives, has been developed. To determine how the laser beam interacts with the high explosives, a theory for the connection between the ignition energy and ...
Henric Östmark +2 more
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Ignition Overpressure in Laser Ignited Reaction and Control Thrusters
50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 2014Advanced ignition systems have been subject of great interest due to the need of developing a new generation of ignition systems for alternative propellant combinations for reaction and control system (RCS) and orbital and manoeuvring system (OMS) thrusters which move away from the classic but toxic hypergolic propellants monomethylhydrazine (MMH) and ...
Manfletti, C., Börner, Michael
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Laser ignition of nanocomposite thermites
Combustion and Flame, 2004Abstract Laser ignition experiments were performed to determine the ignition time of nanoscale particle diameter composites of aluminum (Al) and molybdenum trioxide (MoO3). Ignition time and burn rate were measured as a function of stoichiometry and also as a function of Al particle diameter, which ranged from 17.4 nm to 20 μm.
John J. Granier, Michelle L. Pantoya
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SPIE Proceedings, 1987
A technique for using two lasers operating in tandem to remotely ignite oil pools in the harsh Arctic environment has been developed. A CW CO2 laser "preheats" a localized area of the oil pool for several seconds, thereby raising the surface temperature above the fire-point. A fire is then ignited by a focused high-power pulse from a second laser.
Michael B. Frish +2 more
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A technique for using two lasers operating in tandem to remotely ignite oil pools in the harsh Arctic environment has been developed. A CW CO2 laser "preheats" a localized area of the oil pool for several seconds, thereby raising the surface temperature above the fire-point. A fire is then ignited by a focused high-power pulse from a second laser.
Michael B. Frish +2 more
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Laser-fusion milestone ignites debate
Physics World, 2022After failing to reproduce last year’s record-breaking fusion-energy shot, scientists at the US National Ignition Facility have gone back to the drawing board. Edwin Cartlidge discusses their next steps.
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Dual-pulse laser ignition model
Physics of Fluids, 2018A two-dimensional mathematical model of dual-pulse laser ignition that self-consistently integrates Navier-Stokes, translational and vibrational energy, and neutral and charged species equations has been presented. The results showed that the ignition kernel dynamics depends on the shape and initial energy distribution in the energy spot created by the
Rajib Mahamud +3 more
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Laser Challenges for Fast Ignition
Fusion Science and Technology, 2006AbstractThe laser challenges and state of the art in high-energy, solid-state petawatt lasers for fast ignition (FI) research are reviewed. A number of new laser systems are currently under construction or being planned that will facilitate proof-of-principle FI experiments.
J. D. Zuegel +18 more
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