The operation dynamics of end-pumped solid-state lasers are investigated by means of a spatially resolved numerical rate-equation model and a time-dependent analytical thermal model. The rate-equation model allows the optimization of parameters such as the output coupler transmission and gain medium length, with the aim of improving the laser output performance. The time-dependent analytical th...

a two-dimensional single particle finite element model was used to examine the effects of particle fragmental pattern on the average molecular weights, polymerization rate and particle overheating in heterogeneous ziegler-natta olefin polymerization. a two-site catalyst kinetic mechanism was employed together with a dynamic two-dimensional molecular species in diffusion-reaction equation. the i...

Photon propagation in biological tissue is commonly described by the radiative transfer equation, while the phase function in the equation represents the scattering characteristics of the medium and has significant influence on the precision of solution and the efficiency of computation. In this work, we present a generalized Delta-Eddington phase function to simplify the radiative transfer equ...

A dynamic numerical model was developed to predict the biomass concentration, pH, and carbon dioxide fixation rate in the continuous culture of cyanobacteria in a photobioreactor. The model is based on the growth rate equation of microalgae combined with mass transfer equations for gas and liquid phases in the photobioreactor as well as thermodynamic equilibrium of inorganic carbon ions in the ...

A model for heat-recirculating micro combustor is developed. It investigates the structure of laminar, one-dimensional and steady state flame propagation in uniformly premixed wood particles with considering the effects of heat recirculation caused by configuration of micro combustor. The flame structure is divided into three regions: a preheat-devolatilization zone where the rate of the gas-ph...

The kinetic of Fischer-Tropsch synthesis over a co-precipitated Fe-Ce catalyst was investigated in a fixed bed micro reactor. Experimental conditions were varied as follow: reaction pressure 1-15bar, H¬¬¬2/CO feed ratio of 1-3 and space velocity of 3600-5400 h-1 at the temperature range of 270-310°C. 4 models according to the Langmuir-Hinshelwood-Hougen-Watson (LHHW) type rate equation were der...

For InAs/GaAs(001) quantum dot (QD) system, the wetting layer (WL) evolution and its temperature dependence were studied using reflectance difference spectroscopy and were analyzed with a rate equation model. WL thicknesses showed a monotonic increase at relatively low growth temperatures but showed an initial increase and then decrease at higher temperatures, which were unexpected from a therm...

Regression models are proposed for predicting conception rate in a dairy herd under South African and especially Natal conditions. Conception rate (CR%) was related to mean monthly temperature-humidity index (THI) by curvilinear regression equation model; CR% = 812.7 +/- 28.61 THI - 0.2322THI2 (P = 0.061), and by linear regression equation model; CR% = 188.0 - 1.906THI (P = 0.023). Conception r...

A proximate, biophysical model is proposed describing temperature-modulated variation in growth rate and differentiation rate in ectotherms, based upon the Sharpe–Schoolfield equation connecting enzyme kinetics and biological rates. Like the Sharpe-Schoolfield equation, the model assumes (1) that growth rate and differentiation rate can be described as controlled by one rate-limiting enzyme; in...

We derive a closed master equation for an individual-based population model in continuous space and time. The model and master equation include Brownian motion, reproduction via binary fission, and an interaction-dependent death rate moderated by a competition kernel. Using simulations we compare this individual-based model with the simplest approximation, the spatial logistic equation. In the ...