scholarly journals Inversion of the Degradation Coefficient of Petroleum Hydrocarbon Pollutants in Laizhou Bay

2021 ◽  
Vol 9 (6) ◽  
pp. 655
Author(s):  
Shengmao Huang ◽  
Haiwen Han ◽  
Xiuren Li ◽  
Dehai Song ◽  
Wenqi Shi ◽  
...  
Keyword(s):  
Petroleum Hydrocarbon ◽  
Adjoint Method ◽  
Laizhou Bay ◽  
Actual Distribution ◽  
Physical Chemical ◽  
The Mean ◽  
Simulation Results ◽  
The Given ◽  
Good Agreement ◽  
Degradation Coefficient

When petroleum hydrocarbon pollutants enter the ocean, besides the migration under hydrodynamic constraints, their degradation due to environmental conditions also occurs. However, available observations are usually spatiotemporally disperse, which makes it difficult to study the degradation characteristics of pollutants. In this paper, a model of transport and degradation is used to estimate the degradation coefficient of petroleum hydrocarbon pollutants with the adjoint method. Firstly, the results of a comprehensive physical–chemical–biological test of the degradation of petroleum hydrocarbon pollutants in Laizhou Bay provide a reference for setting the degradation coefficient on the time scale. In ideal twin experiments, the mean absolute errors between observations and simulation results obtain an obvious reduction, and the given distributions can be inverted effectively, demonstrating the feasibility of the model. In a practical experiment, the actual distribution of petroleum hydrocarbon pollutants in Laizhou Bay is simulated, and the simulation results are in good agreement with the observed ones. Meanwhile, the spatial distribution of the degradation coefficient is inverted, making the simulation results closer to the actual observations.

An Analysis on Dynamic Damage on Concrete Obstruct Subjected to Underwater Explosion Shock Waves

2006 ◽  
Vol 306-308 ◽  
pp. 1373-1378
Author(s):  
Li Hao ◽  
Jian Guo Ning
Keyword(s):  
Shock Waves ◽  
Underwater Explosion ◽  
Simulation Method ◽  
C Language ◽  
Damage Degree ◽  
Simulation Results ◽  
The Given ◽  
Dynamic Damage ◽  
Optimum Charge ◽  
Good Agreement

Based on the multi-material Eulerian algorithm, the damage effects of concrete obstruct subjected to underwater explosion shock waves are simulated by using the NM-MMIC code which is a 2D multi-material elastic-plastic hydrodynamics code with C++ language. According to the simulation results of underwater explosion, the optimum charge, the damage degree and the damage laws of obstruct are obtained. The simulation results show a good agreement with that obtained by DYNA2D. Thus the given study indicates that the model and algorithm presented in this paper are reasonable and the simulation method can be used for designing and estimating ammunitions against obstructs in water.

scholarly journals Measuring Hydrometeors Using a Precipitation Microphysical Characteristics Sensor: Sampling Effect of Different Bin Sizes on Drop Size Distribution Parameters

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Xichuan Liu ◽  
Taichang Gao ◽  
Yuntao Hu ◽  
Xiaojian Shu
Keyword(s):  
Drop Size ◽  
Rain Rate ◽  
Monte Carlo Model ◽  
Rain Gauge ◽  
Sampling Schemes ◽  
Distribution Parameters ◽  
Optimum Sampling ◽  
Simulation Results ◽  
The Impact ◽  
Good Agreement

In order to improve the measurement of precipitation microphysical characteristics sensor (PMCS), the sampling process of raindrops by PMCS based on a particle-by-particle Monte-Carlo model was simulated to discuss the effect of different bin sizes on DSD measurement, and the optimum sampling bin sizes for PMCS were proposed based on the simulation results. The simulation results of five sampling schemes of bin sizes in four rain-rate categories show that the raw capture DSD has a significant fluctuation variation influenced by the capture probability, whereas the appropriate sampling bin size and width can reduce the impact of variation of raindrop number on DSD shape. A field measurement of a PMCS, an OTT PARSIVEL disdrometer, and a tipping bucket rain Gauge shows that the rain-rate and rainfall accumulations have good consistencies between PMCS, OTT, and Gauge; the DSD obtained by PMCS and OTT has a good agreement; the probability of N0, μ, and Λ shows that there is a good agreement between the Gamma parameters of PMCS and OTT; the fitted μ-Λ and Z-R relationship measured by PMCS is close to that measured by OTT, which validates the performance of PMCS on rain-rate, rainfall accumulation, and DSD related parameters.

scholarly journals Characterization of Deleterious Mutations in Outcrossing Populations

Genetics ◽  
1998 ◽  
Vol 150 (2) ◽  
pp. 945-956 ◽  
Author(s):  
Hong-Wen Deng
Keyword(s):  
Genetic Variation ◽  
Genetic Variance ◽  
Estimation Bias ◽  
Deleterious Mutations ◽  
Environmental Variance ◽  
Higher Power ◽  
Sib Mating ◽  
The Mean ◽  
Simulation Results

Abstract Deng and Lynch recently proposed estimating the rate and effects of deleterious genomic mutations from changes in the mean and genetic variance of fitness upon selfing/outcrossing in outcrossing/highly selfing populations. The utility of our original estimation approach is limited in outcrossing populations, since selfing may not always be feasible. Here we extend the approach to any form of inbreeding in outcrossing populations. By simulations, the statistical properties of the estimation under a common form of inbreeding (sib mating) are investigated under a range of biologically plausible situations. The efficiencies of different degrees of inbreeding and two different experimental designs of estimation are also investigated. We found that estimation using the total genetic variation in the inbred generation is generally more efficient than employing the genetic variation among the mean of inbred families, and that higher degree of inbreeding employed in experiments yields higher power for estimation. The simulation results of the magnitude and direction of estimation bias under variable or epistatic mutation effects may provide a basis for accurate inferences of deleterious mutations. Simulations accounting for environmental variance of fitness suggest that, under full-sib mating, our extension can achieve reasonably well an estimation with sample sizes of only ∼2000-3000.

scholarly journals Simulation and Experimental Study on Wear of U-Shaped Rings of Power Connection Fittings under Strong Wind Environment

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 735
Author(s):  
Songchen Wang ◽  
Xianchen Yang ◽  
Xinmei Li ◽  
Cheng Chai ◽  
Gen Wang ◽  
...  
Keyword(s):  
Abrasive Wear ◽  
Adhesive Wear ◽  
Surface Hardness ◽  
Wear Depth ◽  
Strong Wind ◽  
Wear Model ◽  
Wind Environment ◽  
Simulation Results ◽  
Oxidation Wear ◽  
Good Agreement

The objective of this study was to investigate the wear characteristics of the U-shaped rings of power connection fittings, and to construct a wear failure prediction model of U-shaped rings in strong wind environments. First, the wear evolution and failure mechanism of U-shaped rings with different wear loads were studied by using a swinging wear tester. Then, based on the Archard wear model, the U-shaped ring wear was dynamically simulated in ABAQUS, via the Umeshmotion subroutine. The results indicated that the wear load has an important effect on the wear of the U-shaped ring. As the wear load increases, the surface hardness decreases, while plastic deformation layers increase. Furthermore, the wear mechanism transforms from adhesive wear, slight abrasive wear, and slight oxidation wear, to serious adhesive wear, abrasive wear, and oxidation wear with the increase of wear load. As plastic flow progresses, the dislocation density in ferrite increases, leading to dislocation plugs and cementite fractures. The simulation results of wear depth were in good agreement with the test value of, with an error of 1.56%.

scholarly journals Quantitative Shape-Classification of Misfitting Precipitates during Cubic to Tetragonal Transformations: Phase-Field Simulations and Experiments

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1373
Author(s):  
Yueh-Yu Lin ◽  
Felix Schleifer ◽  
Markus Holzinger ◽  
Na Ta ◽  
Birgit Skrotzki ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Phase Field ◽  
Phase Field Model ◽  
Invariant Moments ◽  
Plane Normal ◽  
Plane Shape ◽  
Formation And Evolution ◽  
The Given ◽  
Good Agreement

The effectiveness of the mechanism of precipitation strengthening in metallic alloys depends on the shapes of the precipitates. Two different material systems are considered: tetragonal γ′′ precipitates in Ni-based alloys and tetragonal θ′ precipitates in Al-Cu-alloys. The shape formation and evolution of the tetragonally misfitting precipitates was investigated by means of experiments and phase-field simulations. We employed the method of invariant moments for the consistent shape quantification of precipitates obtained from the simulation as well as those obtained from the experiment. Two well-defined shape-quantities are proposed: (i) a generalized measure for the particles aspect ratio and (ii) the normalized λ2, as a measure for shape deviations from an ideal ellipse of the given aspect ratio. Considering the size dependence of the aspect ratio of γ′′ precipitates, we find good agreement between the simulation results and the experiment. Further, the precipitates’ in-plane shape is defined as the central 2D cut through the 3D particle in a plane normal to the tetragonal c-axes of the precipitate. The experimentally observed in-plane shapes of γ′′-precipitates can be quantitatively reproduced by the phase-field model.

Computational Investigation of Different Turbulent Models When Predicting Airflow in an Enclosure

2008 ◽  
Author(s):  
Xi Wang ◽  
Hassan Naji ◽  
Ahmed Mezrhab
Keyword(s):  
Numerical Investigation ◽  
Turbulence Models ◽  
Turbulent Stress ◽  
Computational Investigation ◽  
Isothermal Case ◽  
The Mean ◽  
Turbulent Models ◽  
Rsm Model ◽  
Cold Case ◽  
Good Agreement

In the present study, a numerical investigation is carried out for an isothermal case, a hot case and a cold case with FLUENT code. Three turbulence models are considered: the k-ε realisable model, the RNG k-ε model and the RSM linear model. The obtained results are compared to experiments and show generally a good agreement for the mean velocities and temperatures, but less satisfactory for the turbulent stress. The performance of the RSM model is remarkable. Even if none of the models is able to give the exact experimental pattern on the map of turbulence, the RSM model seems able to predict such configuration.

TCAD Study of the Raised SiGe Source/Drain in 40nm PMOS

2015 ◽  
Vol 645-646 ◽  
pp. 70-74 ◽  
Author(s):  
Min Zhong ◽  
Yu Hang Zhao ◽  
Shou Mian Chen ◽  
Ming Li ◽  
Shao Hai Zeng ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Critical Role ◽  
Sige Layer ◽  
Strain Engineering ◽  
Effect Transistor ◽  
Simulation Results ◽  
Aided Design ◽  
The Relationship ◽  
Growth Experiments ◽  
Good Agreement

An embedded SiGe layer was applied in the source/drain areas (S/D) of a field-effect transistor to boost the performance in the p channels. Raised SiGe S/D plays a critical role in strain engineering. In this study, the relationship between the SiGe overfilling and the enhancement of channel stress was investigated. Systematic technology computer aided design (TCAD) simulations of the SiGe overfill height in a 40 nm PMOS were performed. The simulation results indicate that a moderate SiGe overfilling induces the highest stress in the channel. Corresponding epitaxial growth experiments were done and the obtained experimental data was in good agreement with the simulation results. The effect of the SiGe overfilling is briefly discussed. The results and conclusions presented within this paper might serve as useful references for the optimization of the embedded SiGe stressor for 40 nm logic technology node and beyond.

Numerical Simulation on Thixo-Forging of Magnesium Matrix Composite

2011 ◽  
Vol 189-193 ◽  
pp. 2535-2538 ◽  
Author(s):  
Hong Yan ◽  
Wen Xian Huang
Keyword(s):  
Numerical Simulation ◽  
Matrix Composite ◽  
Metal Flow ◽  
Magnesium Matrix Composite ◽  
Magnesium Matrix ◽  
Simulation Based ◽  
Prior Literature ◽  
Simulation Results ◽  
Computer Numerical Simulation ◽  
Good Agreement

The thixo-forging of magnesium matrix composite was analyzed with computer numerical simulation based on rigid viscoplastic finite element method. The constitutive model of SiCp/AZ61 composite was established in our prior literature. Behavior of metal flow and temperature field were obtained. The differences between traditional forging and thixo-forging processes were analyzed. Results indicated that thixo-forging was better in filling cavity than forging. Simulation results were good agreement with experimental ones.

Development of Advanced CNC Interpolation Algorithm With Consideration of Command and Dynamic Errors

2015 ◽  
Author(s):  
Meng-Shiun Tsai ◽  
Ying-Che Huang
Keyword(s):  
The Other ◽  
Contour Error ◽  
Interpolation Algorithm ◽  
Interpolation Scheme ◽  
Error Equation ◽  
The Past ◽  
Cnc Interpolation ◽  
Dynamic Errors ◽  
Simulation Results ◽  
The Given

In this paper, an integrated acceleration/deceleration with dynamics interpolation scheme is proposed to confine the maximum contour error at the junction of linear junction. The dynamic contour error equation is derived analytically and then it is utilized for the interpolation design. Based on the derived formulations which could predict the command and dynamic errors, the advanced interpolation design could adjust the connecting velocity of the two blocks to confine the overall contour errors under the given tolerance. Simulation results validate the proposed algorithm can achieve higher accurate trajectory as compared to the other interpolation algorithm proposed in the past.

The penetration and ricochet of ogive-nosed rigid projectiles obliquely impacting metallic targets

2021 ◽  
pp. 204141962110377
Author(s):  
Yaniv Vayig ◽  
Zvi Rosenberg
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Dynamic Pressure ◽  
Oblique Impacts ◽  
Simulation Results ◽  
The Impact ◽  
Penetration Depths ◽  
Resistance To Penetration ◽  
Good Agreement

A large number of 3D numerical simulations were performed in order to follow the trajectory changes of rigid CRH3 ogive-nosed projectiles, impacting semi-infinite metallic targets at various obliquities. These trajectory changes are shown to be related to the threshold ricochet angles of the projectile/target pairs. These threshold angles are the impact obliquities where the projectiles end up moving in a path parallel to the target’s face. They were found to depend on a non-dimensional entity which is equal to the ratio between the target’s resistance to penetration and the dynamic pressure exerted by the projectile upon impact. Good agreement was obtained by comparing simulation results for these trajectory changes with experimental data from several published works. In addition, numerically-based relations were derived for the penetration depths of these ogive-nosed projectiles at oblique impacts, which are shown to agree with the simulation results.

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