Abstract:
It is shown that the ultrasound acting on water under ambient conditions causes an increase
in the longitudinal spin relaxation time T1
of the 1
H nuclei measured by means of nuclear spin
echo method at low levels of ultrasound irradiation when the cavitation effects can be neglected.
This effect is due to ultrasonic heating of the water and, as a consequence, to the increase in the
relaxation time T1
with increasing temperature. In the absence of cavitation effects, at low doses
of ultrasonic irradiation, the relaxation time T1
in the distillated water increases linearly with
increasing ultrasound power. In the case of tap water there is a supplementary increase in T1
with
an increasing in ultrasound power P from P = 0 to P = 3.5 W caused by the removal of adsorbed
paramagnetic oxygen molecules from water due to ultrasonic heating. It is given a theoretical
interpretation of the observed linear increase in T1
under increasing in P
Description:
GERU, Ion. Decelerarea relaxării longitudinale a spinilor protonilor în rezonanța magnetică nucleară a apei sub acțiunea ultrasunetului. In: Integrare prin cercetare și inovare: conferința științifică națională cu participare internațională. Ştiinţe ale naturii și exacte, 9-10 noiembrie 2023. CEP USM, 2024, pp. 747-753. ISBN 978-9975-62-690-3