Numerical simulation of optical breakdown for cellular surgery at nanosecond to femtosecond time scales

2001 ◽  
Author(s):  
Alfred Vogel ◽  
Joachim Noack
Keyword(s):  
Numerical Simulation ◽  
Time Scales ◽  
Optical Breakdown

Turbulent dispersion in a non-homogeneous field

1999 ◽  
Vol 392 ◽  
pp. 45-71 ◽  
Author(s):  
ILIAS ILIOPOULOS ◽  
THOMAS J. HANRATTY
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Stochastic Model ◽  
Point Source ◽  
Time Scales ◽  
Langevin Equation ◽  
Turbulent Dispersion ◽  
Homogeneous Field ◽  
Fully Developed Flow ◽  
Good Agreement

Dispersion of fluid particles in non-homogeneous turbulence was studied for fully developed flow in a channel. A point source at a distance of 40 wall units from the wall is considered. Data obtained by carrying out experiments in a direct numerical simulation (DNS) are used to test a stochastic model which utilized a modified Langevin equation. All of the parameters, with the exception of the time scales, are obtained from Eulerian statistics. Good agreement is obtained by making simple assumptions about the spatial variation of the time scales.

Time Scales of DNAPL Migration in Sandy Aquifers Examined via Numerical Simulation

Ground Water ◽  
2007 ◽  
Vol 45 (2) ◽  
pp. 147-157 ◽  
Author(s):  
Jason I. Gerhard ◽  
TiWee Pang ◽  
Bernard H. Kueper
Keyword(s):  
Numerical Simulation ◽  
Time Scales ◽  
Sandy Aquifers

Energy balance of optical breakdown in water at nanosecond to femtosecond time scales

1999 ◽  
Vol 68 (2) ◽  
pp. 271-280 ◽  
Author(s):  
A. Vogel ◽  
J. Noack ◽  
K. Nahen ◽  
D. Theisen ◽  
S. Busch ◽  
...  
Keyword(s):  
Energy Balance ◽  
Time Scales ◽  
Optical Breakdown

Numerical Simulation of a Multi-Component Reacting Flow in a Supersonic DC Torch Nozzle

1996 ◽  
Author(s):  
C. George ◽  
E. Pfender ◽  
H.-D. Steffens
Keyword(s):  
Numerical Simulation ◽  
Time Scales ◽  
Fluid Dynamic ◽  
Low Pressure ◽  
Reacting Flow ◽  
Exchange Reactions ◽  
Hydrogen Atoms ◽  
Species Transport ◽  
Pressure Plasma ◽  
Low Pressure Plasma

Abstract Maximizing dissociated species transport in plasma assisted chemical vapor deposition (CVD), is important in many low pressure plasma jet processes. To deposit high quality diamond by low pressure plasma assisted CVD, it is important to maximize the atomic hydrogen transport to the substrate. One route to process improvement is to explore ways in which unstable species transport can be maximized. A two-dimensional computational model of a supersonic contoured nozzle attached to a dc torch will be described for examining the chemical non-equilibrium of the flow. If the fluid dynamic time scales of interest are faster than the kinetic time scales of interest, it is believed that unstable precursor transport can be controlled, improved and optimized. This paper will examine an implicit formulation for the numerical simulation of a multi-component reacting Ar-H2 plasma. It is found that dissociation, ionization and charge exchange reactions must all be included in a reaction model. The ionic species significantly alter the temperature profiles upstream of nozzle choking. However, to increase the number of hydrogen atoms at the nozzle exit, the arc attachment should be positioned as close as possible to the converging-diverging nozzle throat.

Numerical Simulation of a Dielectric Material Exposed to Short Pulsed Laser Radiation

2001 ◽  
Author(s):  
Richard A. Whalen ◽  
Gregory J. Kowalski
Keyword(s):  
Numerical Simulation ◽  
Heat Conduction ◽  
Time Scales ◽  
Thermal Transport ◽  
Dielectric Material ◽  
Index Of Refraction ◽  
Hyperbolic Heat Conduction ◽  
Focal Volume ◽  
Simulation Code ◽  
Radial Temperature

Abstract A numerical simulation code is developed to study laser beam propagation and the significance of self-focussing or defocusing effects on a manufacturing process. The solution method includes the thermally stimulated nonlinear optical effects caused by the temperature and intensity dependent index of refraction. The results demonstrate that radial temperature gradient magnitudes of 0.06 to 0.6°C produce significant changes in the focal volume of the beam. The magnitudes of the temperature changes are directly related to differences in the absorption coefficient. The thermal transport of the absorbed radiation is modeled using Fourier heat conduction for long time scales and Hyperbolic heat conduction for short time scales. The focal volume of the beam is significantly altered by the differences between these thermal transport mechanisms. These results were determined using a simulation of a Z-scan measurement technique.

scholarly journals Radio Frequency Numerical Simulation Techniques Based on Multirate Runge-Kutta Schemes

2012 ◽  
Vol 2012 ◽  
pp. 1-21 ◽  
Author(s):  
Jorge F. Oliveira ◽  
José C. Pedro
Keyword(s):  
Numerical Simulation ◽  
Radio Frequency ◽  
Time Scales ◽  
Electronic Circuit ◽  
Circuit Simulation ◽  
One Dimensional ◽  
Simulation Techniques ◽  
Runge Kutta ◽  
The One ◽  
Electronic Circuit Simulation

Electronic circuit simulation, especially for radio frequency (RF) and microwave telecommunications, is being challenged by increasingly complex applications presenting signals of very different nature and evolving on widely separated time scales. In this paper, we will briefly review some recently developed ways to address these challenges, by describing some advanced numerical simulation techniques based on multirate Runge-Kutta schemes, which operate in the one-dimensional time and also within multidimensional frameworks.

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