This paper considers an epidemic model of a vector-borne disease which has the vectormediated transmission only. The incidence term is of the bilinear mass-action form. It is shown that the global dynamics is complete...
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This paper considers an epidemic model of a vector-borne disease which has the vectormediated transmission only. The incidence term is of the bilinear mass-action form. It is shown that the global dynamics is completely determined by the basic reproduction number Ro. If Ro ≤ 1. the diseasefree equilibrium is globally stable and the disease dies out. If Ro 〉 1. a unique endemic equilibrium is globally stable in the interior of the feasible region and the disease persists at the endemic equilibrium. Numerical simulations are presented to illustrate the results.
Turbulent mixing layer flow was simulated by the discrete vortex method, and viscosity was modeled by the random walk method and the solid wall was represented by the vortex sheet in the simulation. The predictions of...
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Turbulent mixing layer flow was simulated by the discrete vortex method, and viscosity was modeled by the random walk method and the solid wall was represented by the vortex sheet in the simulation. The predictions of the profiles of mean velocity and turbulent flow parameters agree well with experimental data. The results show that the peak value of Reynolds shear stress increases but the fluctuations of the peak value occur because of vortex-pairing, and vorticity peak value increases in the downstream direction. Then the effect of Reynolds number on the distribution of the turbulent flow parameters at the same velocity ratio was explored. It seems that the peak values of Reynolds shear stress under different Reynolds numbers will increase at the similar slope in the downstream direction. The average vorticity peak value will decrease in the downstream direction, and the decrease rate will increase with Reynolds number. In addition, the vorticity peak value in each section will increase nearly linearly with Reynolds number.
The dimension of erythrocyte is close to capillary diameter and in microcirculation blood should be treated as a two-phase flow system, i.e., erythrocytes suspended in plasma. The rheological property of erythrocytes ...
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The dimension of erythrocyte is close to capillary diameter and in microcirculation blood should be treated as a two-phase flow system, i.e., erythrocytes suspended in plasma. The rheological property of erythrocytes will significantly influence the hemodynamics. In our experiment, the motion and deformation of erythrocytes in a microfluidic chip with rectangular cross-section microchannel was captured by optical microscope and high speed CCD camera. The aggregation, deformation and common movement forms of erythrocytes were observed under different viscosity, hematocrit and velocity. It was found that erythrocytes behaved a regular biconcave disc shape at low velocity and low-to-medium viscosity, and always rolled and rotated themselves in their movement. At high velocity and medium viscosity, RBCs elongated obviously along the flow direction and presented a flat oval shape together with a tank-treading motion (TTM).
multiphase {1. induced CO2 corrosion has resulted in serious losses in oil and gas production. In this paper, gas‐liquid two‐phase vertical upward slug {1. has been analyzed from aspects containing {1. structure,...
multiphase {1. induced CO2 corrosion has resulted in serious losses in oil and gas production. In this paper, gas‐liquid two‐phase vertical upward slug {1. has been analyzed from aspects containing {1. structure, hydrodynamic characteristics, mass transfer characteristics and their effects on pipe wall and corrosion product film, and it is found that slug {1. has a distinct effect on transports of corroding species to and of corrosion products from the wall, momentum interchange between fluid and wall and the formation and damage of corrosion product film. In addition, the transports of corrosive species and corrosion product are also an important step in CO2 corrosion process. It is assumed that the slug {1. induced CO2 corrosion of pipeline is dependent on the non‐linear coupling of the characteristics including the shear stress, the normal stress, the mass transfer coefficient, and the electrochemical reaction.
Oxidation within the system CCl4/CH4/O2/N2 is studied at atmospheric pressure in a tubular flow reactor to investigate the influence of reaction temperature and chlorine content on chlorinated waste combustion and fin...
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Oxidation within the system CCl4/CH4/O2/N2 is studied at atmospheric pressure in a tubular flow reactor to investigate the influence of reaction temperature and chlorine content on chlorinated waste combustion and find incineration process optimization methods for pollution *** reaction temperature varies from 700℃ to 1.00℃ and the CCl4/CH4(or Cl/H) mole ratio of the inlet mixture varies from 0.21.to *** profiles are measured with *** is shown that at the same initial CCl4 concentration and reaction temperature adding CH4 favors CCl4 destruction and CO2 *** the destruction and removal efficiency(DRE) of CH4 decreases with lower Cl/H and higher concentrations of toxic products of incomplete combustion such as COCl2 and CH3Cl are formed at the same *** chlorine in the system favors CH4 decomposition,but it also inhibits further oxidation of *** temperature assists in both CCl4 destruction and CH4 conversion,and the concentration of toxic combustion intermediates is *** the temperature is the most effective way to enhance CCl4 *** CO2 concentration increases with temperature.A CO concentration peak is observed around 800℃:with a certain Cl/H,the CO concentration first increases with temperature and then *** effect of increasing CH4 concentration on CCl4 destruction becomes mild above 900℃.Rather,it enhances the interaction between chlorine and carbonaceous radicals,which leads to higher concentration of toxic products.
The attempt of the author in this research is made to calculate a heat transfer coefficient (HTC) by combining the filmwise theory with the dropwise notion for ethanol‐water mixtures condensation. A new model, includ...
The attempt of the author in this research is made to calculate a heat transfer coefficient (HTC) by combining the filmwise theory with the dropwise notion for ethanol‐water mixtures condensation. A new model, including ethanol concentration, vapor pressure and velocity, is developed by introducing a characteristic coefficient to combine the two mentioned‐above theories. Under different concentration, pressure and velocity, the calculation is in comparison with experiment. It turns out that the calculation value is in good agreement with the experimental result; the maximal error is within ±30.1.. In addition, the model is applied to calculate related experiment in other literature and the values obtained agree well with results in reference.
To investigate the mechanism of active control for flow separation in rectangle diffuser by vortex generator jets (VGJs) method, numerical analysis with large-eddy simulation and experimental measurement by particle i...
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The first-passage problem of dynamical power system of a single-machine-infinite-bus (SMIB) system under random perturbations is ***,the stochastic averaging method for quasi non-integrable generalized Hamiltonian sys...
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The first-passage problem of dynamical power system of a single-machine-infinite-bus (SMIB) system under random perturbations is ***,the stochastic averaging method for quasi non-integrable generalized Hamiltonian systems is applied to reduce the equations of the SMIB system under random perturbations to a set of averaged It ***,the backward Kolmogorov equation governing the conditional reliability function and the Pontryagin equation governing the conditional mean of first passage time are established and solved numerically,***,the proposed method is verified by using the Monte Carlo simulation of the original system.
ZnS‐CuInS2‐AgInS2 solid solution photocatalysts were successfully prepared by co‐precipitation method with heat treatment under different atmosphere ( N2 and H2S). XRD, XRF, UV‐vis, and SEM were used to characteri...
ZnS‐CuInS2‐AgInS2 solid solution photocatalysts were successfully prepared by co‐precipitation method with heat treatment under different atmosphere ( N2 and H2S). XRD, XRF, UV‐vis, and SEM were used to characterize the prepared photocatalysts, indicated that the composition of result photocatalysts were different from each other and also the rate of charge, though they possessed a wurtzite‐type phase structure. The photocatalysts all showed photocatalytic activities for H2 evolution from aqueous solutions containing SO32− and S2− as sacrificial reagents under visible light irradiation with Ru loading, but sample treated under H2S atmosphere performed better, the possible reason was proposed.
Combustion chamber components (cylinder head-cylinder liner-piston assembly-fuel film) were treated as a coupled body. Based on the three-dimensional numerical simulation of heat transfer of the coupled body, the mult...
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Combustion chamber components (cylinder head-cylinder liner-piston assembly-fuel film) were treated as a coupled body. Based on the three-dimensional numerical simulation of heat transfer of the coupled body, the multi-dimensional simulation computation coupling flow and solid on working process and combustion chamber components of internal combustion engine was performed using Discrete Transfer Radiation Model (DTRM) radiation heat transfer model, zoning solution method and boundary coupling method. The simulation was applied to the influence investigation of the space non-uniformity in radiation heat transfer among combustion chamber components on the generation of in-cylinder soot emissions. The results show that the space non-uniformity in heat transfer among the combustion chamber components has great influence on the generation of in-cylinder NOx emissions. The difference value of total soot in cylinder when exhaust valves are opened is 1.3% (no radiation), 0.8% (radiation). So the effect of radiation heat transfer space non-uniformity of combustion chamber components on total soot production can be ignored. While in local area radiation heat transfer space non-uniformity has certain effect on soot production inside whole combustion chamber space, and has less effect on soot production in the area near the wall of combustion chamber components.
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