CORRECT DETERMINATION OF INTEGRAL CONDUCTIVITY IN SOLVING INCORRECT INVERSE PROBLEMS OF ELECTROMAGNEIC LOGGING

The paper suggests and investigates a problem statement of well-logging inverse problem that is based on the integral conductivity parameter to describe a geoelectric section. Approach was introduced for a layered cylindrical model with radially heterogeneous continuous distribution of electric properties that parametrize the problem with a function of total longitudinal conductivity. The results of hydrodynamic modeling for oil/fresh water- and brine-based drilling muds were used to study multiple propagation resistivity tool signal equivalency for two classes of models with continuous and piece-wise constant conductivity distribution. Physically based algorithm enabling one to convert one model class to the other, preserving the signal equivalency was proposed. It was demonstrated that the radial models with different radial conductivity distribution and similar integral conductivity curves are equivalent. This fact lays a rationale of using the integral conductivity parameters along with conductivity while inversion. The integral conductivity parameter can be used to build the functionals, whose minimization improves algorithm stability and enables determining functional parameters in hydrodynamic filtration models.

Filter-less submicron hydrodynamic size sorting

We push the limits of hydrodynamic filtration by demonstrating filter-less sorting of submicron particles, in line with the model and simulations.

Hydrodynamic Filtration

Prospects of hydrodynamic filters application are demonstrated through the review of current state of hydrodynamic filtering. Acknowledged schemes of hydrodynamic filters are Classified by 3 parameters: presence/absence of sludge liquid, frame and filter design, extra force field creation means. Advantages and disadvantages of every type of hydrodynamic filter are noted. Major attitudes to hydrodynamic filtering are considered with deterministic approach. Special attention is paid to hydrodynamic filters with flow vortex of “cylinder in cylinder” and “cylinder in cone” types. Promicing directions for further research of Hydrodynamic filtration are proposed.

Sorting of human mesenchymal stem cells by applying optimally designed microfluidic chip filtration

This paper presents sorting of human stem cells by applying optimally designed microfluidic chips based on the hydrodynamic filtration principle.