Two-dimensional visualization of excitation temperature and chemical species in divertor plasmas: Trace CD molecules by chemical sputtering of fusion plasma reactor wall

2013 ◽  
Vol 106 ◽  
pp. 174-179 ◽  
Author(s):  
Zhe Cui ◽  
Kenji Kodama ◽  
Masanori Yamamoto ◽  
Qingchun Shen ◽  
Mitsuaki Yoshimi ◽  
...  
Keyword(s):  
Plasma Reactor ◽  
Chemical Species ◽  
Reactor Wall ◽  
Excitation Temperature ◽  
Two Dimensional ◽  
Fusion Plasma ◽  
Chemical Sputtering

scholarly journals Chemical identification through two-dimensional electron energy-loss spectroscopy

2020 ◽  
Vol 6 (28) ◽  
pp. eabb4713
Author(s):  
Renwen Yu ◽  
F. Javier García de Abajo
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Electronic Device ◽  
Theoretical Calculations ◽  
Chemical Species ◽  
High Sensitivity ◽  
Two Dimensional ◽  
Excitation Spectra ◽  
Electron Energy Loss

We explore a disruptive approach to nanoscale sensing by performing electron energy loss spectroscopy through the use of low-energy ballistic electrons that propagate on a two-dimensional semiconductor. In analogy to free-space electron microscopy, we show that the presence of analyte molecules in the vicinity of the semiconductor produces substantial energy losses in the electrons, which can be resolved by energy-selective electron injection and detection through actively controlled potential gates. The infrared excitation spectra of the molecules are thereby gathered in this electronic device, enabling the identification of chemical species with high sensitivity. Our realistic theoretical calculations demonstrate the superiority of this technique for molecular sensing, capable of performing spectral identification at the zeptomol level within a microscopic all-electrical device.

scholarly journals Two-dimensional CFD simulation and pilot-scale experimental verification of a downdraft gasifier: effect of reactor aspect ratios on temperature and syngas composition during gasification

2020 ◽  
Vol 7 (3) ◽  
pp. 536-550
Author(s):  
Chootrakul Siripaiboon ◽  
Prysathyrd Sarabhorn ◽  
Chinnathan Areeprasert
Keyword(s):  
Steady State ◽  
Temperature Profile ◽  
Fuel Consumption ◽  
Cfd Simulation ◽  
Pilot Scale ◽  
Reactor Wall ◽  
Two Dimensional ◽  
High Concentration ◽  
Downdraft Gasifier ◽  
Aspect Ratios

Abstract This paper focuses on a two-dimensional CFD simulation of a downdraft gasifier and a pilot-scale experiment for verification using wood pellet fuel. The simulation work was carried out via the ANSYS-Fluent CFD software package with in-house coding via User Defined Function. Three gasification parameters were taken into account in the simulation and validation to achieve highly accurate results; namely, fuel consumption, temperature profile, and syngas composition. After verification of the developed model, the effects of aspect ratios on temperature and syngas composition were investigated. Results from simulation and experimental work indicated that the fuel consumption rate during the steady state gasification experiment was 1.750 ± 0.048 g/s. The average steady state temperature of the experiment was 1240.32 ± 14.20 K. In sum, the fuel consumption and temperature profile during gasification from modeling and experimentation show an error lower than 1.3%. Concentrations of CO, CO2, H2, and CH4 were 20.42 vol%, 15.09 vol%, 8.02 vol%, and 2.6 vol%, respectively, which are comparable to those of the experiment: 20.00 vol%, 15.48 vol%, 8.00 vol%, and 2.65 vol%. A high concentration of syngas is observed in the outer radial part of the reactor because of the resistive flow of the air inlet and the synthesis gas produced. The average temperatures during the steady state of the gasifier with aspect ratios (H/D) of 1.00, 1.38 (experiment), and 1.82 were 978.77 ± 11.60, 1256.46 ± 9.90, and 1368.94 ± 9.20 K, respectively. The 1.82 aspect ratio reactor has the smallest diameter, therefore the radiative heat transferred from the reactor wall affects the temperature in the reactor. Syngas compositions are comparable. Inverse relationships between the aspect ratios and the syngas LHV, (4.29–4.49 MJ/N m3), cold gas efficiency (29.66% to 31.00%), and carbon conversion (79.59% to 80.87%) are observed.

Visualization of Two-Dimensional Excitation Temperatures in CH4/N2/Ar Plasmas for Preparation of Carbonaceous Materials

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Qingchun Shen ◽  
Yasushi Miyata ◽  
Shigeaki Morita ◽  
Yoshinobu Baba ◽  
Kuniyuki Kitagawa ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Lithium Ion Batteries ◽  
Vapor Deposition ◽  
Reaction Mechanisms ◽  
Anode Materials ◽  
Lithium Ion ◽  
Chemical Vapor ◽  
Excitation Temperature ◽  
Two Dimensional ◽  
Carbonaceous Materials

Analysis of the two-dimensional (2D) distribution of excited Ar atoms has been made to synthesize better anode materials for lithium-ion batteries. The 2D visualization of excitation temperatures was based on the “two-line” method, which are important to diagnose the plasmas used for the preparation of carbonaceous materials by plasma enhanced chemical vapor deposition. The results showed that the excitation temperature in N2-rich (CH4-lean) plasma was lower than that in N2-lean (CH4-rich), and is attributed to different excitation and reaction mechanisms of CH4 and N2.

Modeling a high power fusion plasma reactor-type ion source: Applicability of particle methods

2012 ◽  
Vol 19 (4) ◽  
pp. 043506 ◽  
Author(s):  
G. Fubiani ◽  
G. J. M. Hagelaar ◽  
J. P. Boeuf ◽  
S. Kolev
Keyword(s):  
High Power ◽  
Plasma Reactor ◽  
Ion Source ◽  
Particle Methods ◽  
Fusion Plasma ◽  
Reactor Type

Plasma-Reactor Wall Interactions: Bromine-Fluorine Chemistry Duality in an Industrial Dry Etch Process

2015 ◽  
Vol 1803 ◽  
Author(s):  
M. Rizquez ◽  
A. Roussy ◽  
B. Bortoloti ◽  
J. Pinaton ◽  
Y. Goasduff
Keyword(s):  
Plasma Reactor ◽  
Industrial Process ◽  
Etching Process ◽  
Reactor Wall ◽  
Silicon Etching ◽  
Fluorine Chemistry ◽  
Starting Point ◽  
Dry Etch ◽  
Over Time ◽  
Wall Interactions

ABSTRACTThe purpose of the present paper is to investigate the composition of the coating formed on the plasma reactor walls after an industrial process which is divided into two steps, where the chemistries used are CF4/CH2F2 followed by HBr/O2. Since Fluorine traces have been detected through the plasma and over the wafer even during the second chemistry, investigations of the Br-F chemistry duality for a new silicon etching process have been performed in order to see the reactions which are taking place inside of the reactor. The understanding of these formations is really important to avoid process instabilities and get better performance of the transistors. The coating on the walls after the process and after the cleaning between wafers has been characterized in order to figure out the level of F traces after each step and to understand the reminiscence of this element over time. This study is the starting point to propose a modification on the Waferless AutoClean (WAC) used nowadays in an industrial process.

Quantitative Two-Dimensional Infrared (2D IR) Spectroscopy: Theoretical Development for General and Specific Cases

1995 ◽  
Vol 49 (9) ◽  
pp. 1243-1253 ◽  
Author(s):  
Sanong Ekgasit ◽  
Hatsuo Ishida
Keyword(s):  
Ir Spectroscopy ◽  
Chemical Species ◽  
Quantitative Relationship ◽  
Theoretical Development ◽  
Spectroscopic Techniques ◽  
Two Dimensional ◽  
2D Ir ◽  
Correlation Strength ◽  
The Relationship ◽  
Spectral Intensities

A quantitative two-dimensional correlation analysis for various spectroscopic techniques is introduced. Normalization of the spectral intensities enables two-dimensional infrared (2D IR) spectroscopy to be used for quantitative purposes. As a result of the normalization, the correlation strengths are characterized by the dynamic parameters of the correlated spectral intensities. Relationships between the chemical species associated with peak positions in 2D IR spectra are characterized by both the magnitude and the sign of the correlation strength. The magnitude describes the degree of harmonization, while the sign shows the relationship between the dynamic behaviors of the correlated spectral intensities. The phase spectrum, which indicates the quantitative relationship among the dynamic behavior of the spectral intensities, is also introduced.

scholarly journals Numerical modeling of disperse material evaporation in axisymmetric thermal plasma reactor

2003 ◽  
Vol 7 (1) ◽  
pp. 63-99 ◽  
Author(s):  
Predrag Stefanovic ◽  
Dejan Cvetinovic ◽  
Goran Zivkovic ◽  
Simeon Oka ◽  
Pavle Pavlovic
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Thermal Plasma ◽  
Gas Flow ◽  
Disperse Material ◽  
Plasma Reactor ◽  
Solid Particles ◽  
Reactor Wall ◽  
Particle Injection ◽  
Injection Angle

A numerical 3D Euler-Lagrangian stochastic-deterministic (LSD) model of two-phase flow laden with solid particles was developed. The model includes the relevant physical effects, namely phase interaction, panicle dispersion by turbulence, lift forces, particle-particle collisions, particle-wall collisions, heat and mass transfer between phases, melting and evaporation of particles, vapour diffusion in the gas flow. It was applied to simulate the processes in thermal plasma reactors, designed for the production of the ceramic powders. Paper presents results of extensive numerical simulation provided (a) to determine critical mechanism of interphase heat and mass transfer in plasma flows, (b) to show relative influence of some plasma reactor parameters on solid precursor evaporation efficiency: 1 - inlet plasma temperature, 2 - inlet plasma velocity, 3 - particle initial diameter, 4 - particle injection angle a, and 5 - reactor wall temperature, (c) to analyze the possibilities for high evaporation efficiency of different starting solid precursors (Si, Al, Ti, and B2O3 powder), and (d) to compare different plasma reactor configurations in conjunction with disperse material evaporation efficiency.

scholarly journals MATHEMATICAL MODELLING OF MACROSEGREGATION IN INGOT CASTING

2018 ◽  
Vol 17 (2) ◽  
pp. 74
Author(s):  
M. O. Assunção Jr ◽  
M. Vynnycky
Keyword(s):  
Mathematical Model ◽  
Three Dimensional ◽  
Chemical Species ◽  
Ternary Alloys ◽  
Ingot Casting ◽  
Two Dimensional ◽  
Computational Simulations ◽  
Macroscopic Scale ◽  
Three Dimensional Models

The occurrence of macrosegregation in alloys produced by ingot casting can adversely affect the quality of the final product. Macrosegregation can be described as a severe variation on the macroscopic scale of the chemical species that compose the alloy, and the ability of computational simulations to predict such defects remains far from perfect. Therefore, this research focuses on the development of a two-dimensional mathematical model that - through computational simulations - could be applied to study and predict the formation of macrosegregation in the ingot casting of binary alloys. Once accomplished, this work can establish the framework to new studies that will tackle more advanced problems, e.g., for actual ingot geometries, three-dimensional models and industrially-important ternary alloys.

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