Development of a numerical simulation of depth profiles of multilayers composed of very thin layers

1989 ◽  
Vol 14 (9) ◽  
pp. 524-528
Author(s):  
M. Dapor ◽  
F. Marchetti
Keyword(s):  
Numerical Simulation ◽  
Thin Layers ◽  
Depth Profiles

scholarly journals Reliability and Comparison of Some GEANT4-DNA Processes and Models for Proton Transportation: An Ultra-Thin Layer Study

2021 ◽  
Author(s):  
Gabriela Hoff ◽  
Raquel S. Thomaz ◽  
Leandro I. Gutierres ◽  
Sven Muller ◽  
Viviana Fanti ◽  
...  
Keyword(s):  
Cross Sections ◽  
Radiation Transport ◽  
Thin Layers ◽  
Depth Profiles ◽  
Chemical Damage ◽  
Diffusion Parameters ◽  
Experiment Versus ◽  
Deposited Energy ◽  
Simulation Results ◽  
Dynamic Diffusion

This chapter presents a specific reliability study of some GEANT4-DNA (version 10.02.p01) processes and models for proton transportation considering ultra-thin layers (UTL). The Monte Carlo radiation transport validation is fundamental to guarantee the simulation results accuracy. However, sometimes this is impossible due to the lack of experimental data and, it is then that the reliability evaluation takes an important role. Geant4-DNA runs in an energy range that makes impossible, nowadays, to perform a proper microscopic validation (cross-sections and dynamic diffusion parameters) and allows very limited macroscopic reliability. The chemical damage cross-sections reliability (experiment versus simulation) is a way to verify the consistency of the simulation results which is presented for 2 MeV incident protons beam on PMMA and PVC UTL. A comparison among different Geant4-DNA physics lists for incident protons beams from 2 to 20 MeV, interacting with homogeneous water UTL (2 to 200 nm) was performed. This comparison was evaluated for standard and five other optional physics lists considering radial and depth profiles of deposited energy as well as number of interactions and stopping power of the incident particle.

Research and Application for Fire Flood New Technologies in Liaohe Oilfield

2015 ◽  
Vol 737 ◽  
pp. 878-881
Author(s):  
De Zhu Liu ◽  
Xiao Ming Wu
Keyword(s):  
Numerical Simulation ◽  
New Technologies ◽  
Thin Layers ◽  
Air Injection ◽  
Technical Parameters ◽  
Liaohe Oilfield ◽  
Different Types ◽  
Production Wells ◽  
Temperature And Pressure ◽  
In Fire

Necessary new technologies have been developed in Liaohe oilfield for fire flood pilot and have been used in different types of reservoirs and wells. Reusable igniter is developed and reasonable technical parameters is decided after numerical simulation. The power is up to 80kW and the injection air can the heated to 500°C enough to ignite oil in reservoir. New air injection tube which has the function of igniting oil layers separately is also developed for reservoir with many thin layers. Integrated tube designed for horizontal production wells in THAI pilot is also planned and useful. This tube has the function of supervising temperature and pressure, blending water or steam to reduce temperature or heat produced oil to inform the ordinary production of THAI. Every kind of new technologies solve the problems we meet in fire flood pilot and expected result have been got in Gao2-3,Du66 and some other fire flood pilot districts.

Depth Profiling of the Optical Absorption Coefficient in Ultraviolet-Degraded Poly(Vinylchloride) Films by Dual Beam Light Profile Microscopy

2005 ◽  
Vol 59 (4) ◽  
pp. 511-518 ◽  
Author(s):  
J. F. Power ◽  
S. W. Fu ◽  
O. V. Nepotchatykh
Keyword(s):  
Optical Absorption ◽  
Absorption Coefficient ◽  
Thin Layers ◽  
Chemical Degradation ◽  
Optical Absorption Coefficient ◽  
Concentration Profiles ◽  
Layer By Layer ◽  
Depth Profiles ◽  
Dual Beam ◽  
Visible Wavelengths

Dual beam laser light profile microscopy (LPM) was applied in this work to the depth mapping of the optical absorption coefficient in photo-degraded poly(vinyl chloride) films. Depth profiles followed the absorption coefficient of a conjugated polyene photoproduct at visible wavelengths in photolyzed films of approximately 200 μm thickness. Both continuous and layered (separable laminate) films were studied. The absorption coefficient profiles reconstructed from photo-degraded thin films showed the classic concentration profiles seen in the literature for PVC degraded in the presence of oxygen and nitrogen atmospheres. In the case of single thin layers with continuous properties, the depth profiles were smooth and regular with minimum spatial noise. In the LPM of laminate structures, more optical anomalies were present because of the multi-ply interfacial structures that appeared in both the images and the reconstructed depth profiles. Notwithstanding, it was possible to profile the optical absorption coefficient at a level of error comparable to standard microtome methods. The latter was determined by comparing the LPM results to a destructive layer-by-layer analysis performed in parallel on the imaged materials. The dual beam LPM method should be generally useful for establishing polyene concentration profiles in industrial materials produced by photochemical, thermal, and chemical degradation mechanisms.

Laser Hardening of XC42 Steel: Numerical Analysis of Quenched Area

2010 ◽  
Vol 636-637 ◽  
pp. 1165-1171 ◽  
Author(s):  
E. Saavedra ◽  
Alberto Ramil ◽  
Ana J. López ◽  
J.C. Álvarez
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Laser Processing ◽  
Laser Hardening ◽  
Specific Information ◽  
Maximum Hardness ◽  
Maximum Width ◽  
Depth Profiles ◽  
Finite Element Numerical Simulation ◽  
Good Behaviour

In contrast with conventional tools, laser processing allows hardening of a restricted zone while keeping the structural properties of the steel bulk. This last quality indicates that, in order to verify a laser hardening, only some specific information of the quenched area is required. The aim of this article is to analyse the reliability of finite element numerical simulation by comparing numerical and experimental outcomes. To do that, we define some magnitudes: the maximum width, the real depth of the laser penetration, the maximum hardness and the hardness versus depth profiles (Jominy’s curves). The tests show the good behaviour of the model and how this contributes important information to the choice of the laser parameters.

UPTAKE OF LIGHT ELEMENTS IN THIN METALLIC FILMS

2001 ◽  
Vol 15 (28n29) ◽  
pp. 1382-1390
Author(s):  
ANDREAS MARKWITZ ◽  
MATHIAS WALDSCHMIDT
Keyword(s):  
Diffusion Processes ◽  
Limit Of Detection ◽  
Ion Beam ◽  
Thin Layers ◽  
Double Layers ◽  
Nuclear Reaction Analysis ◽  
Metallic Films ◽  
Elastic Recoil ◽  
Carbon And Nitrogen ◽  
Depth Profiles

Ion beam analysis was used to investigate the influence of substrate temperature on the inclusion of impurities during the deposition process of thin metallic single and double layers. Thin layers of gold and aluminium were deposited at different temperatures onto thin copper layers evaporated on silicon wafer substrates. The uptake of oxygen in the layers was measured using the highly sensitive non-resonant reaction 16 O(d,p) 170 O at 920 keV. Nuclear reaction analysis was also used to probe for carbon and nitrogen with a limit of detection better than 20 ppm. Hydrogen depth profiles were measured using elastic recoil detection on the nanometer scale. Rutherford backscattering spectroscopy was used to determine the depth profiles of the metallic layers and to study diffusion processes. The combined ion beam analyses revealed an uptake of oxygen in the layers depending on the different metallic cap layers and the deposition temperature. Lowest oxygen values were measured for the Au/Cu layers, whereas the highest amount of oxygen was measured in Al/Cu layers deposited at 300°C. It was also found that with single copper layers produced at various temperatures, oxygen contamination occurred during the evaporation process and not afterwards, for example, as a consequence of the storage of the films under normal conditions for several days. Hydrogen, carbon, and nitrogen were found as impurities in the single and double layered metallic films, a finding that is in agreement with the measured oxidation behaviour of the metallic films.

scholarly journals The layered structure of stably stratified turbulent shear flows

2019 ◽  
Vol 55 (4) ◽  
pp. 13-26
Author(s):  
A. V. Glazunov ◽  
E. V. Mortikov ◽  
K. V. Barskov ◽  
E. V. Kadancev ◽  
S. S. Zilitinkevich
Keyword(s):  
Numerical Simulation ◽  
Temperature Gradient ◽  
Richardson Number ◽  
Numerical Models ◽  
Measurement Data ◽  
Stable Stratification ◽  
Thin Layers ◽  
Turbulent Shear ◽  
Large Temperature ◽  
Turbulent Heat

The data of numerical simulation of stably stratified turbulent Couette flows are analyzed for various values of the Richardson number. Two different methods were used: Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES). It is shown that the flow contains large organized structures, along with chaotic turbulence, regardless of the simulation method. These structures appear as inclined layers in the temperature field with weakly stable stratification, separated by very thin layers with large temperature gradients. The existence of such layered structures in nature is indirectly confirmed by the analysis of field measurement data on the meteorological mast, where temperature gradient distribution histograms are found to be far from the normal distribution and similar to temperature gradient probability distributions obtained by numerical models data. The simulations indicate an increase of the turbulent Prandtl number with increasing of the gradient Richardson number. It is highly likely that the identified structures serve as effective barriers for vertical turbulent heat flux, without the blocking of momentum transfer. We proposed the hypothesis, that it is precisely these structures that serve as the physical mechanism for maintaining turbulence under supercritically stable stratification.

Numerical Simulation of Thermoplastics in a Short Pulsed Laser Welding Process

2006 ◽  
Author(s):  
Richard A. Whalen ◽  
Gregory J. Kowalski
Keyword(s):  
Numerical Simulation ◽  
Laser Welding ◽  
Laser Intensity ◽  
Welding Process ◽  
Thin Layers ◽  
Simulation Code ◽  
Transmission Laser Welding ◽  
Lap Welding ◽  
Thermo Physical Properties ◽  
Laser Welding Process

A numerical simulation code is developed and used to investigate the differences in thermal behavior and the size of the heat affected zone (HAZ) in a short pulsed transmission laser welding process (>0.5 ps (1/e2)). The numerical model uses both a Fourier and Hyperbolic thermal model. The welding process involves the lap welding of two thin layers of thermoplastic films. The investigated welding conditions are transparent material over a semi-transparent or opaque material. The results provide temperature profiles that illustrate the differences between the predicted temperatures of the two thermal models as well as the effects of laser intensity and material thermo-physical properties.

Numerical Simulation of Thermal Stress Fields in Thermoplastics in a Pulsed Laser Welding Process

2007 ◽  
Author(s):  
Gregory J. Kowalski ◽  
Richard A. Whalen
Keyword(s):  
Numerical Simulation ◽  
Thermal Stress ◽  
Pulsed Laser ◽  
Welding Process ◽  
Pulse Velocity ◽  
Thin Layers ◽  
Published Data ◽  
Simulation Code ◽  
Incident Laser Radiation ◽  
Lap Welding

A numerical simulation code is developed and used to derive relationships between the incident laser radiation, the thermal stress field, and the size and shape of the heat affected (HAZ) and melt zones for a pulsed laser transmission welding process. The material used in the investigation is a high density polyethylene thermal plastic. The numerical model uses the Fourier heat conduction thermal model and the welding process involves the lap welding of two thin layers of thermoplastic films with the welding conditions of a transparent material over a semi-transparent or opaque material. The Fourier model is valid due to the high thermal pulse velocity through the material. The results are compared to the published data on thermoplastic welding criteria and the legitimacy of these criteria are discussed.

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