Keiji Yasuda 교수

The dependence of the sonochemical reaction on ultrasonic intensity was studied over a wide frequency range of 22-1960 kHz and sample volume range of 25-200 mL. The effect of a stainless steel reflector set on the water surface was also considered. Experiments were carried out by direct ultrasonic irradiation of a sample in a vessel. The potassium iodide (KI) method was used to evaluate the sonochemical reaction in terms of efficiency and reaction rate, and calorimetry was used to determine ultr

We investigated the time variation of ultrasonic degassing for air-saturated water and degassed water with a sample volume of 100 mL at frequencies of 22, 43, 129, 209, 305, 400, 514, 1018, and 1960 kHz and ultrasonic power of 15 W. Ultrasonic degassing was evaluated by dissolved oxygen concentration. Ultrasonic degassing was also investigated at a frequency of 1018 kHz and ultrasonic powers of 5, 10, 15, and 20 W. The dissolved oxygen concentration varied with the ultrasonic irradiation time an

The mass flow rate of ultrasonic atomization was estimated by measuring the vaporization amount from a bulk liquid with a fountain. The effects of ultrasonic frequency and intensity on the atomization characteristics were investigated when the directivities of the acoustic field from a transducer were almost the same. The sample was distillated water and the ultrasonic frequencies were 0.5, 1.0, and 2.4 MHz. The mass flow rate of ultrasonic atomization increased with increasing ultrasonic intens

The effects of carrier gas conditions on the concentration of ethanol by ultrasonic atomization are examined. With increasing height from vessel bottom to gas inlet and outlet, the ethanol content in the accompanied liquid increases and the flow rate of alcohol decreases. The ethanol content in the accompanied liquid becomes lower as the gas velocity becomes higher. The attachment of a demister is effective for the increase of the content in the accompanied liquid.

The agitation effects on sonochemical reaction were investigated using a sonochemical reactor at 486 kHz. Agitator type, rotation speed, and ultrasonic irradiation direction were changed and the sonochemical reaction performances of aqueous solutions of potassium iodide (KI) and tetraphenylporphine tetrasulfonic acid (TPPS) were measured. The installation of a turbine agitator led to increase in the sonochemical reaction rates of KI and TPPS for the irradiation from the bottom wall in the reacto

Effect of ultrasonic cavitation on sound pressure at the fundamental, second harmonic, and first ultraharmonic frequencies was investigated from low to high ultrasonic intensities. The driving frequencies were 22, 304, and 488 kHz. Sound pressure was measured using a needle-type hydrophone and ultrasonic cavitation was estimated from the broadband integrated pressure (BIP). With increasing square root of electric power applied to a transducer, the sound pressure at the fundamental frequency line

The mass flow rate of ultrasonic atomization was estimated by measuring the vaporization amount from a bulk liquid with a fountain. The effects of ultrasonic frequency and intensity on the atomization characteristics were investigated when the directivities of the acoustic field from a transducer were almost the same. The sample was distillated water and the ultrasonic frequencies were 0.5, 1.0, and 2.4 MHz. The mass flow rate of ultrasonic atomization increased with increasing ultrasonic intens

The effect of the superposition location of ultrasonic fields on the sonochemical reaction rate was investigated using a sonochemical reactor with four transducers at 486 kHz. The transducers were attached at the bottom, upper side middle side, and lower side of a vessel. The reaction rate of potassium iodide in aqueous solution was measured. In the cases of the upper and bottom transducers, and the lower and bottom transducers, the synergy effect of sonochemical efficiency was observed. The amo