The results of a study on the geometric shape of the damper on the efficiency of the ultrasonic piezoelectric transducer are presented. In particular, a damper in the form of a truncated cone is ...considered, the generatrix of which has an inclination angle α relative to the diameter of the piezoceramic plate. The shape of the damper in the form of a truncated cone is chosen based on the a priori assumption that this helps to increase the path of the wave in the damper material due to numerous reflections in it. A criterion for the efficiency of damper operation is proposed. The optimal (from the point of view of the damper efficiency) value of the angle α was determined theoretically and experimentally. The technology of its production is described. Satisfactory agreement between the results of theoretical and experimental studies was noted.
We present the results of studying the influence of the geometric shape of the damper on its effectiveness and the overall efficiency of the emission–reception system. One of possible shapes for the ...damper is considered where it is a truncated cone with the generatrix tilted relative to the piezoelectric plate plane. A criterion for evaluating the efficiency of the damper operation is proposed. The study includes the results of computational-theoretical (using the finite element method) and experimental research on the influence of the tilt angle of the damper generatrix on the signal reflected from its rear part. The generatrix tilt angle at which the minimum of noise signal is achieved is determined. A study of the emission–reception system under load on the aquatic environment is carried out. A satisfactory agreement between the theoretical and experimental results is noted.
Background: Comaneci (Rapid Medical) is a compliant, adjustable mesh that provides temporary scaffolding during coiling of wide-necked intracranial aneurysms (WNAs) that preserves antegrade flow. We ...report our early multi-institutional experience with the Comaneci device in the USA. Method: We reviewed all patients with WNAs that were treated using the Comaneci device for coil remodeling of ruptured and unruptured aneurysms at 4 institutions between July 2019 and May 2020. Clinical characteristics, angiographic variables, and endovascular results were assessed. Results: A total of 26 patients were included (18 women). The mean age was 62.7 years (range 44–81). Fifteen patients presented with ruptured aneurysms and 11 with unruptured aneurysms. The mean aneurysm neck width was 3.91 mm (range 1.9–6.5) with a mean dome-to-neck ratio of 1.57 (range 0.59–3.39). The mean maximum width was 5.80 mm (range 3.0–9.9) and the mean maximum height was 5.61 mm (range 2.0–11.8). Successful aneurysm occlusion was achieved in 25 of 26 patients. Complete occlusion was achieved in 16 patients, near-complete occlusion was observed in 9 patients, and 1 patient demonstrated residual filling. The mean time of device exposure was 24 min (range 8–76). No vasospasm was observed at the device location. Clot formation on the device was noted in 2 separate cases, but there were no clinical sequelae. There was 1 intraprocedural complication in a case that involved the simultaneous use of 2 Comaneci devices. Conclusions: Our initial experience shows that the Comaneci device is a promising and reliable tool that can safely support coil remodeling of WNAs.
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