activity-depth profiles by the diffusion-convection model
نویسندگان
چکیده
The diffusion-convection model of Cs transport has been used to evaluate the activity-depth profiles of soils in southwestern Nigeria in this study. The experimentally determined depth profiles were fitted into the diffusion-convection equation to obtain the diffusion coefficient D and the convective velocity . Results obtained showed that the range of the diffusion coefficient was 0.72 – 1.02 cm per year while that of the convective velocity was from 0.07 to 0.16 cm per year. It was observed that the diffusion coefficient is higher than the convective velocity in all the sampling points. The low convective velocities obtained in all the locations may imply that convective rates of the radionuclide within the soil layers are insignificant compared to the diffusion rates.
منابع مشابه
Development of an Implicit Numerical Model for Calculation of Sub and Super Critical Flows
A two dimensional numerical model of shallow water equations was developed tocalculate sub and super-critical open channel flows. Utilizing an implicit scheme the steady stateequations were discretized based on control volume method. Collocated grid arrangement was appliedwith a SIMPLEC like algorithm for depth-velocity coupling. Power law scheme was used fordiscretization of convection and dif...
متن کاملVertical Structure and Double Diffusion Convection of the Water Column in the Southern Shores of the Caspian Sea
Background and Objectives: Different types of instability occur at sea. Layered structures are one of the most important physical phenomena in marine environments. Static stability and double diffusion are associated with density changes with respect to depth and temperature and salinity gradients, respectively. Due to the difference in temperature and salinity in the water column, marine areas...
متن کاملDevelopment of an Implicit Numerical Model for Calculation of SUB-and Super-Critical Flows
A two dimensional numerical model of shallow water equations was developed to calculate sub and super-critical open channel flows. Utilizing an implicit scheme the steady state equations were discretized based on a control volume method. Collocated grid arrangement was applied with a SIMPLEC like algorithm for depth-velocity coupling. A power law scheme was used for discretization of convection...
متن کاملModel study reservoir flushing
Sediment flushing of reservoirs is an operational technique, whereby previously accumulated sediments in the reservoirs are hydraulically removed by accelerated flow when the bottom desiltingoutlets of the dam are opened. In this research, the process of sediment flushing is simulated by a three dimensional numerical model in which sediment and flow interaction are reflected in the reservoirs. ...
متن کاملStratification and Double-Diffusive Convection in the Bab-el-Mandeb Strait during Winter Monsoon
Investigation of stratification in marine environments is always considered by researchers. In this study double-diffusive convection and stratification in the Bab el Mandeb strait is investigated by analyzing of field data. Measurement of seawater temperature and salinity from ARGO project (2009 to2014) and also R-V Knorr (2001) cruise with the daily average of seawater temperature and salinit...
متن کامل