rate equation
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2022 ◽  
Author(s):  
Sabina Markelj ◽  
Matic Pečovnik ◽  
Thomas Schwarz-Selinger ◽  
Mitja Kelemen

Abstract In this work the synergism between displacement damage creation and presence of hydrogen isotopes was studied. Tungsten samples were irradiated by 10.8 MeV W ions with or without the presence of D ions with two different energies of 300 eV/D and 1000 eV/D and different temperatures. In order to compare the results obtained with different exposure parameters the samples were afterwards additionally exposed to D ions at 450 K to populate the created defects. By increasing the W irradiation time, ion flux and energy, the increase of D concentration and D retention was observed as measured by nuclear reaction analysis and thermal desorption spectroscopy. By fitting the D depth profiles and D desorption spectra by the rate equation code MHIMS-R we could see that additional fill-levels were populated with higher flux and ion energy which ends up in higher final D concentration and retention as compared to experiments with lower D flux and energy.


Author(s):  
Yoshiyuki Honda ◽  
Shinji Motokoshi ◽  
Takahisa Jitsuno ◽  
Kana Fujioka ◽  
Toshihiro Yamada ◽  
...  

Abstract The concentration dependence of energy transfer from Cr3+ to Nd3+ at the 4T1 level excitation in Nd/Cr:YAG was investigated by the fluorescence decay curves of Cr3+ and Nd3+ for Nd/Cr:YAG and Cr:YAG ceramic powders in the Cr3+ concentration range of 0.1 to 6.0 mol%. The energy transfer process between Cr3+ and Nd3+ at the 4T1 level excitation is tried to explain using a rate equation that assumes energy transfer from the 2E–4T2 level to Nd3+ on the basis of dipole–dipole interactions, the same as the 4T2 level excitation. In conclusion, the energy excited to the 4T1 level will relax non-radiatively to the 2E–4T2 level and then transfer to Nd3+. It is presumed there will be no direct transfer from the 4T1 level to Nd3+. Our rate equations will be useful when simultaneously exciting the 4T1 and 4T2 levels of Cr3+ in Nd/Cr:YAG using broadband pumping sources.


2021 ◽  
Vol 9 (2) ◽  
pp. 71-84
Author(s):  
Rahmawati Yusuf ◽  
Resmawan Resmawan ◽  
Boby Rantow Payu

Using the regression model, a method that accommodates variables related to each other is called the simultaneous equation method. The study aims to determine the factors affecting inflation and rupiah exchange rate and model simultaneous equations towards the factors affecting inflation and rupiah exchange rate in Indonesia using Two-Stage Least Square. Data used in this study are secondary data obtained from the website of Statistics of Indonesia. Findings on the simultaneous equation model with two-stage least squares reveal that variables that significantly affect inflation are the Indonesia rupiah exchange rate and money supply. At the same time, variables that significantly affect the Indonesian rupiah exchange rate are inflation and money supply. The predictive value using the inflation and rupiah exchange rate equation indicates that the obtained MAPE (Mean Absolute Percentage Error) value does not exceed 50%. In conclusion, the prediction result using the inflation and Indonesia rupiah exchange rate equation is accurate.


Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2767
Author(s):  
Yu Liu ◽  
Ziwen Zhou ◽  
Shaojian Zhang ◽  
Enming Zhao ◽  
Jing Ren ◽  
...  

To date, the mechanisms of Er3+ upconversion luminescence via 980 and 1530 nm excitation have been extensively investigated; however, based on discussions, they either suffer from the lack of convincing evidence or require elaborated and time-consuming numerical simulations. In this work, the steady-state and time-resolved upconversion luminescence data of Er3+-doped NaYF4 were measured; we therefore investigated the upconversion mechanisms of Er3+ on the basis of the spectroscopic observations and the simplified rate equation modeling. This work provides a relatively simple strategy to reveal the UCL mechanisms of Er3+ upon excitation with various wavelengths, which may also be used in other lanthanide ion-doped systems.


2021 ◽  
Author(s):  
Zhen Chen ◽  
Tareq Shaalan ◽  
Ali Dogru

Abstract Complex well model has proved to be important for capturing the full physics in wellbore, including pressure losses, multiphase effects, and advanced device modelling. Numerical instability may be observed especially when the well is produced at a low rate from a highly productive multi-phase zone. In this paper, a new multi-level nonlinear solver is presented in a state-of-the-art parallel complex wellbore model for addressing some difficult numerical convergence problems. A sequential two-level nonlinear solver is implemented, where the inner solver is used to address the convergence in the constraint rate equation, and then the entire complex network is solved using an outer solver. Finally, the wellbore model is coupled with the grid solution explicitly, sequentially, or implicitly. This novel formulation is robust enough to greatly improve the numerical stability due to the lagging in the computation of mixture density in wellbore constraint rate equation and the variation in the fluid composition over Newton iterations in network nonlinear solver. The numerical challenge in the complex well model and the improvement of performance with the new nonlinear solver are demonstrated using reservoir simulation. Models with complex wells running into convergence problems are constructed and simulated. With this novel nonlinear solver, simulation gives much more reliable results on well productions without numerical oscillations and computational cost is much less.


Author(s):  
Meghmala R. Sangvikar ◽  
Gayatri M. Phadnaik ◽  
Omprakash S. Chavan

The kinetics of DMSO (dimethylsulphoxide) assisted one pot cyclocondensation of bisanilino disulphide and 1,3-dicarbonyls has been investigated using spectral method. The kinetic measurements have been carried by varying media, temperature and concentration of the reactants. The assistance of DMSO is investigated. The order of reaction, effects of substituents with dicarbonyls on the rates and thermodynamic parameters has also been reported. First time reaction conditions are optimised for performing the cyclocondensation conveniently and rapidly. Probably mechanism has been proposed and order of reaction was determined on the basis of rate expression and was in agreement with second order rate equation, used for the determination of rate constants.


Author(s):  
William J. Hankins ◽  
Robert A. Frederick ◽  
David M. Lineberry
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