The confined impinging jet reactor (CIJR) has attracted wide interest in the past few years because of the efficient micromixing that it offers. In this work, the CIJR is characterized over a wide range of mixing conditions, using three measures of performance: estimates of the energy dissipation rate, micromixing efficiency based on the yield of a homogeneous reaction, and particle size resulting from a heterogeneous precipitation reaction. The energy dissipation results showed very good agreement between four methods, with values up to 100 times greater than those observed in stirred tanks. The reactions showed a higher sensitivity to mixing conditions at higher concentrations, with less effect of mixing at high flow rates. The operation of the CIJR was very robust to changes in flow rate, with stable performance for up to a 30% difference in the inlet flows.
This article proposes a robust technique for needle detection and tracking using three-dimensional ultrasound (3D US). It is difficult for radiologists to detect and follow the position of micro tools, such as biopsy needles, that are inserted in human tissues under 3D US guidance. To overcome this difficulty, we propose a method that automatically reduces the processed volume to a limited region of interest (ROI), increasing at the same time the calculation speed and the robustness of the proposed technique. First, a line filter method that enhances the contrast of the needle against the background is used to facilitate the initialization of ROI using the tubularness information of the complete US volume. Then, the random sample consensus (RANSAC) and Kalman filter (RK) algorithm is used in the ROI to detect and track the precise position of the needle. A series of numerical inhomogeneous phantoms with a needle simulated from real 3D US volumes are used to evaluate our method. The results show that the proposed method is much more robust than the RANSAC algorithm when detecting the needle, regardless of whether or not the insertion axis corresponds to an acquisition plane in the 3D US volume. The possibility of failure is also discussed in this article.
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