A modified boundary condition of velocity for continuity equation with non-uniform density distribution at outlet boundary plane

Boundary conditions in computational fluid dynamics significantly affect the prediction of flow field. However, the outlet boundary conditions for the continuity equation have been rarely investigated. In addition, the velocities at the outlet boundary might not be accurately predicted with the conventional outlet boundary conditions when a flow that has non-uniform density distribution on the outlet boundary is simulated. In the present study, we modified a boundary condition for the continuity equation in consideration of the non-uniform density distribution on the outlet boundary plane, comparing the numerical results of combustion between the conventional and modified boundary conditions. As a result, the proposed boundary condition can resist the generation of an unrealistic temperature field better than the conventional methods

Improvement of the prediction accuracy of NO emissions in counter-flow diffusion flames on using NO mass fraction as a progress variable

Computational fluid dynamics has been widely used to predict the production of nitrogen oxide (NO). Flamelet approach is commonly used as a modelling technique to perform turbulent combustion simulations. As the prediction of NO emissions with the flamelet approach is not reliable, when predicting the NO emission, the NO emissions are calculated with the conservation equation of NO mass fraction, and the NO production rate is predicted with the flamelet approach. In this study, we used the mixture fraction and NO mass fraction to predict the NO production rate in the conservation equation of the NO mass fraction, comparing the numerical results calculated with proposed method with those with the conventional methods and detailed chemistry model. Numerical simulations of counter-flow diffusion flames where NO was not supplied, that was supplied with fuel, and that was supplied with oxidizer indicated that the distribution of NO mole fraction calculated with the proposed method was in better agreement with that of the detailed chemistry model than that of the conventional methods

A Brief Review on How to Make a Database for Flamelet Approach

The simulation of turbulent combustion has been of more importance to develop practical combustors. The flamelet (or tabulated chemistry) approach is one of the techniques to estimate combustion reaction rate and to describe turbulent combustion field. This approach can reduce computational cost in comparison with the reduced reaction schemes because the combustion reaction rate is just looked up from the pre-calculated database. The difficulty of the flamelet approach comes from the variety of how to make this pre-calculated database. In the present study, we reviewed previous researches in terms of the flamelet approach and summarized the ideas to make the database for the flamelet approach. First, the fundamental combustion reaction models such as the detailed reaction model and skeletal model were introduced. And then, how to generate the dataset for the database in flamelet, flamelet progress variable, and flamelet generated manifolds models were mentioned. Moreover, how to process the dataset into the database for the turbulent combustion simulation was pointed out. Finally, apart from making the database, the treatment of the database in the computational fluid dynamics was described briefly

Turbulent combustion simulation based on flamelet model

Turbulent combustion simulation based on flamelet mode

VEGF concentration increased in the 50/10 oxygen-induced retinopathy model compared to room air

<p><b>Copyright information:</b></p><p>Taken from "Neutralizing antibody to VEGF reduces intravitreous neovascularization and may not interfere with ongoing intraretinal vascularization in a rat model of retinopathy of prematurity"</p><p></p><p>Molecular Vision 2008;14():345-357.</p><p>Published online 11 Feb 2008</p><p>PMCID:PMC2258217.</p><p></p> A: Vascular endothelial growth factor (VEGF). VEGF concentration was increased in the 50/10 oxygen-induced retinopathy (OIR) model compared to RA at all time points (overall ANOVA

Phosphorylated VEGFR2 by Western blot in 50 ng neutralizing antibody to vascular endothelial growth factor and IgG injected eyes

<p><b>Copyright information:</b></p><p>Taken from "Neutralizing antibody to VEGF reduces intravitreous neovascularization and may not interfere with ongoing intraretinal vascularization in a rat model of retinopathy of prematurity"</p><p></p><p>Molecular Vision 2008;14():345-357.</p><p>Published online 11 Feb 2008</p><p>PMCID:PMC2258217.</p><p></p> No difference in retinal vascular endothelial growth factor receptor 2 (VEGFR2) phosphorylation to total VEGFR2 from eyes injected with either 50 ng neutralizing antibody to VEGF (VEGFab) or control IgG at 12 and assayed at 13 (p=0.648, Student’s -test)

First in-situ measurements of HF radar echoing targets

The sounding rocket Investigation of Cusp Irregularities 2 (ICI-2) was launched into the cusp ionosphere over Svalbard to investigate the production of decameter scale irregularities in the electron plasma associated with HF radar backscatter. The main mission objective was to obtain high-resolution measurements of decameter scale electron plasma irregularities and to quantify the growth rate for the gradient drift instability (GDI). At the 5.7 kHz sampling rate of the absolute density measurements, ICI-2 has provided the first documentation in terms of absolute electron density measurements of how 10-m structures are located on km scale electron density gradients. ICI-2 traversed a cusp electron density structure created by ongoing soft precipitation. 10-m scale irregularities were generated at km scale density gradients. The estimated growth time for the GDI process was 10–50 seconds

Lectin-stained flat mounts of retinas in pups exposed to oxygen-induced retinopathy or room air at p18 and p25

<p><b>Copyright information:</b></p><p>Taken from "Neutralizing antibody to VEGF reduces intravitreous neovascularization and may not interfere with ongoing intraretinal vascularization in a rat model of retinopathy of prematurity"</p><p></p><p>Molecular Vision 2008;14():345-357.</p><p>Published online 11 Feb 2008</p><p>PMCID:PMC2258217.</p><p></p> A: Rat pups exposed to the 50/10 oxygen-induced retinopathy (OIR) model developed IVNV at the junctions of vascular and avascular retina after return to room air (RA). Retinal flat mounts were made and stained with isolectin to reveal the retinal vasculature and intravitreous neovascularization (IVNV) at the junction of vascular and avascular retina at p18 in 50/10 oxygen-induced retinopathy (50/10 OIR)(A) or room air (RA) B: Lectin-stained retinal flat mount from a p18 RA rat pup. C, D: Lectin-stained retinal flat mounts from OIR (C) and RA (D) pups at p25. An example of IVNV has been enlarged for clarity (inset, A)