Ultrasonic manipulation for precise positioning and equidistant transfer of inertial confinement fusion microspheres.

As the thermonuclear fuel container, the inertial confinement fusion (ICF) microspheres must be detected before the ICF experiment to maximize the profits of fusion reactions. However, in the current detection method, the ICF microsphere is in direct contact with the measurement platform, resulting in the ICF microsphere surface being easily damaged during the detection process. In this paper, an ultrasonic manipulation method is proposed, realizing non-destructive, high-precision, and high-efficient manipulation of the ICF microsphere by switching the two acoustic fields produced in the liquid. When detecting the ICF microsphere, the first acoustic field (1st AF) accurately traps the microsphere in the acoustic field center to achieve its precise positioning. And when the ICF microsphere is failed to pass the detection, it is transferred out of the microscope measurement area by switching to the second acoustic field (2nd AF). Two solid vibration modes, their corresponding acoustic fields, and the two acoustic streaming fields are first computed by the finite element method. Then, the manipulation experiments indicated that the ICF microspheres can be first driven to the center of the 1st AF and then be positioned here with a minimum positional fluctuation of 1.1 µm. By changing to the 2nd AF, the positioned microsphere can be transferred nearly 11 mm to the nearest antinode from the acoustic field center. Finally, based on the proposed ultrasonic manipulation method, the detection experiments of the ICF microsphere were carried out, illustrating that the positioning of the 1st AF meets the requirements of the morphology detection and the radius measurement of the ICF microsphere. The proposed method holds the advantages of non-destructive, high-precision, simple control scheme and meets the practical application needs of the microsphere fixed-point detection, presenting the potential promise for the field of microsphere detection.

Study on a novel omnidirectional ultrasonic cavitation removal system for Microcystis aeruginosa.

Microcystis aeruginosa, as a typical alga, produces microcystin with strong liver toxicity, seriously endangering the liver health of human and animals. Inhibiting the bloom of the Microcystis aeruginosa in lakes becomes a significant and meaningful work. Ultrasonic cavitation is currently considered to be the most environmentally friendly and effective method for the removal of Microcystis aeruginosa. However, the commercialized ultrasonic algae removal systems require multi-Langevin transducers to achieve omnidirectional ultrasonic irradiation due to the single irradiation direction of the Langevin transducer, resulting in the complex design and high energy consumption. To achieve a low-cost, simple structure, and high-efficiency algae removal system, a novel omnidirectional ultrasonic cavitation removal system for Microcystis aeruginosa is proposed. The proposed system is major composed of a novel omnidirectional ultrasonic transducer, which generates the omnidirectional ultrasonic irradiation by its shaking-head motion coupled by two orthogonal bending vibration modes. Modal simulation, sound field simulation, and cavitation bubble radius simulation are first carried out to optimize the geometric sizes of the proposed transducer and verify the correctness of the omnidirectional ultrasonic irradiation principle. Then the vibration characteristics of the transducer prototype are measured by vibration tests and impedance tests. Finally, the feasibility and effectiveness of the proposed omnidirectional ultrasonic removal system for Microcystis aeruginosa are evaluated through the algae removal experiments. The experimental results exhibit that the algal cells damaged by ultrasonic irradiation from the proposed system do not have the ability to self-repair. In addition, the algal removal rates reached 55.41% and 72.97% after 30 min of ultrasonic treatment when the corresponding ultrasonic densities are 0.014 W/mL and 0.021 W/mL, respectively. The proposed omnidirectional ultrasonic algae removal system significantly simplifies the configuration and reduces energy consumption, presenting the potential promise of algae removal and environmental protection.

Finite Element Simulation Study of Ultrasonic Vibration-Assisted Tensile High-Volume Fraction SiCp/Al Composite.

Silicon carbide particle-reinforced aluminum matrix composite (SiCp/Al) has been widely used in the military and aerospace industry due to its special performance; however, there remain many problems in the processing. The present paper introduces an ultrasonic vibration tensile apparatus and a composite tensile specimen and performs Abaqus finite element simulation on high-volume SiCp/Al. The results show that the stress-strain curve increases linearly during conventional tensile strength; the intermittent vibration tensile strength is similar to the full course vibration tensile strength: The magnitude of the stress reduction increases as the amplitude of the ultrasound increases and the vibration frequency increases. The tensile rate is inversely proportional to the magnitude of the stress reduction, and in the ultrasonic parameters, the amplitude has the greatest influence on the magnitude of the stress reduction, followed by the tensile rate; additionally, the frequency has the least influence on the magnitude of the stress reduction. The experimental results show that the simulation results are consistent with the experimental results.