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The paper deals with the finite element modeling and simulation of lab‐on‐a‐chip microfluidic device that is used for counting leukocytes in blood samples. Some aspects regarding the state of the art of lab‐on‐a‐chip devices are presented. These microfluidic devices offer the possibility to perform certain determinations, as it is the case of T lymphocytes, which are impossible by current conventional equipment. Comsol multiphysics and stationary laminar flow module are used for finite element modeling and simulating of device working, and for its geometric optimization. The velocities and the required travel time of the blood sample combined with the lysing and stop lysing substances, within two dedicated circuits are determined. These are formed by multiple coils, two counting channels for two cell types and a cells capture chamber. Then, the execution specifications of the lab‐on‐a‐chip on a millimetric silicon wafer are delivered, by microtechnologies, the modelling results being validated. [ABSTRACT FROM AUTHOR]

The paper deals with increasing the precision by electrodischarge machining, aided by ultrasonic longitudinal vibration of the electrode tool. Increasing the dimensional precision of machined surfaces is strongly related to the decrease of volumetric relative wear. This essential parameter of electrodischarge machining depends on several input parameters, which are described in detail. Several optimization conditions, concerning the technological input parameters, are elaborated, aiming at the maximization of the dimensional precision through volumetric relative wear. These conditions address overall parameters as acoustic pressure, discharge energy level and power supply of the ultrasonic chain. Several technological solutions are elaborated like the synchronization of pulses with tool oscillation semiperiods, decreasing the supply power of the acoustic chain and working with frontal flat surfaces of electrodes by generating complex surfaces through 3D technological movements provided by CNC machines. All these can lead to up to 50% decrease of volumetric relative wear. [ABSTRACT FROM AUTHOR]