Application Research on Groundwater Circulation Exploration Based on Fluent Simulation

It is very important to study the groundwater circulation and water chemistry evolution in the management and protection of water pollution. We use the Fluent simulation technology and the isotope tracer method to do simulation on the flow and distribution of groundwater. In the simulation process we set the model of Fluent isotope labeling group, and enter the groundwater flow parameters in the boundary condition, including water viscosity, osmotic pressure, and the average flow velocity. We use isotope tracer method to simulate the water flow. Finally, according to the law of groundwater flow, we predict the evolution rules of groundwater chemical by using the inverse geochemical simulation technology. It provides a theoretical basis for the management and protection of groundwater pollution.

Methodological considerations in measuring human calcium absorption: relevance to study the effects of inulin-type fructans

During the last 50 years, a variety of methods have been developed to estimate Ca absorption in man. Mass balances were initially used, but these were unable to accurately measure fractional Ca absorption because they cannot distinguish unabsorbed dietary Ca from endogenous faecal Ca excretion (excretion of previously absorbed Ca back into the gut). A number of isotopic methods have been developed that can measure true fractional Ca absorption, employing radioisotopes, stable isotopes, or both. Different methods involve collection of urine, faecal or plasma samples. Of the currently available methods, the dual isotope tracer method with a timed urine collection is probably the most precise and reliable. It is also relatively straightforward to carry out and avoids the need for a faecal collection. The purpose of the present paper is to discuss the general advantages and disadvantages of the different methods of Ca absorption. In addition, the limitations the different methods have in examining the possible effects of non-digestible oligosaccharides on Ca absorption will be discussed.