Papers by Keyword: Ultrasound

Abstract: In present paper principles of acoustic scattering in case hardened components were discussed. Improvements of ultrasonic testing method and instrument development opportunities were proposed. Through these investigations, it would be possible to provide an advanced method of ultrasonic testing of case hardening quality, which might be applied in Russian metallurgical industry market. Comparative analysis of characteristics of existing instrument and the proposed instrument was conducted. This article demonstrates all important advantages of the proposed method of nondestructive testing for quality control of heavy-loaded components.

Abstract: Combination of disinfection method gives advantages. In this work, inactivation of E. coli using ZnO nanofluids and ultrasound is evaluated. Growth curves of bacteria were investigated to reveal the inactivation activities of ZnO nanofluids and ultrasound. The effects of combination of ZnO nanofluids and ultrasound, ultrasound time, ultrasound induction point and the induction order of ZnO nanofluids and ultrasound were studied. The results suggested that combination of ZnO nanofluids and ultrasound gives better inactivation effect on E. coli when comparing with single disinfection method. Ultrasound for 10 s helped ZnO nanofluids inhibiting bacteria better than ultrasound for 30 s /60 s. Ultrasound induction point (at 0 hr, 2 hr or 4hr) did not affect on ZnO nanofluids to exhibit the inhibiting property. Induction ultrasound prior to adding ZnO nanofluids showed the better inactivation effect on E. coli. The results also displayed that in this work, ultrasound was mainly worked as a pre-treatment step, instead of a disinfection method.

Abstract: In this paper, a variable-focus ultrasonic liquid lens controlled by the external voltage is demonstrated. That is, the liquid lens can be reshaped with the external voltage, which will cause the focal length to change. The relationship between liquid lens’ shape and the control voltage was obtained. The influence factors of the response time were researched. And the distribution of the ultrasonic field after the lens under different external control voltages was simulated.

Abstract: This paper reports a design proposal of a sonochemical setup for pesticide wastewater degradation. Multi-parameters obtained by multi-sensors of the setup were utilized to control experimental variables and analyze degradation effect. Based on the setup and method designed, degradation experiments of deltamethrin were set up. In the work, treatments using ultrasonic, ozone, and the combination of them were carried out respectively, and parameters including ultrasonic frequency, pH, electrical conductivity, temperature as well as mass were taken into consideration. Results indicated that deltamethrin could be degraded efficiently under the irradiation of 589 kHz US/O₃ combined and the degradation rate could reach 91%.

Abstract: Based on phonon theory the interaction of high frequency sound (ultrasound and hypersonic) with crystal lattices in solids was estimated. The coefficients of absorption in dielectrics and metals, with respect to temperature and sound frequency, were calculated. Analysis of the calculated dependences allows obtaining of nanomaterials with the set sound conductivity and sound absorption in high frequency range.

Abstract: An optical method to determine a speed of sound (or ultrasound) in water was described in this work. The measuring system composes of ultrasonic transducer, glass water bath, He-Ne laser source, lens, and screen. An ultrasound fog generator used for producing an ultrasound with a frequency f of 1.74 MHz was immersed in DI water. It was fixed at one side of water bath. When the sound wave travels in water along the length of water bath, a standing wave is obtained from the interference of the incidence wave and the wave reflected from the opposite side of water bath. The node and antinode of the standing wave act as an opaque and transparent medium. As a He-Ne laser beam with a wavelength of 632.8 nm travelled to a convex lens with a focal length of 5 cm and diverged through the sound field, an enlarged standing wave pattern was shown on a white screen. The wavelength of sound wave λ was obtained using geometry (similar triangle). Therefore, the speed of ultrasound in water was calculated by v = fλ. In this work, the water temperature was varied in a range of 15 - 39 °C. The results showed that the speed of sound increased with increasing the water temperature. The percentage error was below 2.8. This proposed method can be used for demonstrating physics principles such as waves and optics for high school students and undergraduates.

Abstract: The dyeing of cotton fabrics using mulberry leaves (Morus alba L.) as a natural dye has been studied in both conventional heating and ultrasonic techniques. The extractability of Mulberry leaves dye from natural origin using power ultrasonic was also evaluated in comparison with conventional heating. The mulberry leaves extract to provided brown-green to green color, depending on the pH concentration. The results of dye extraction indicate that power ultrasonic is rather effective than conventional heating at low temperature and short time. The effects of dye bath pH, dyeing time, dyeing temperature and mordants were studied and the colorimetric parameters L*, a*, b* of dyed fabrics with ultrasonic and conventional techniques were compared.

Abstract: Ultrasonic melt processing enjoys the revival of interest in the last 1015 years. Although the main fundamental works as well as lab-scale and pilot-scale demonstrations date back to the 1950-1980s, the ultrasonic melt processing of light metals has not become a major technology. Recently the deficiencies of current technological approaches brought back the interest to ultrasonic treatment for degassing, grain refinement and composite materials. The current attempts to repeat the earlier results, to gain more fundamental insight using advanced means available and to up-scale the positive effects to the industrial scale show frequent lack of understanding of the basic controlling mechanisms. This paper describes the main mechanisms of ultrasonic melt processing, shows frequent mistakes, and gives some guidelines for technology up-scaling. The paper is illustrated with the latest experimental results.

Abstract: Deep desulfurization of a hydrotreated diesel fuel was investigated with H₂O₂ oxidation coupled with solvent extraction intensified by ultrasound. The process parameters for the oxidation desulfurization of diesel fuel, such as the type and dosage of catalyst, co-solvent, ultrasound time, molar ratio of H₂O₂ and sulfur were investigated. The results showed that sulfur content of the hydrotreated diesel fuel was reduced from 140 ppm to 10 ppm with using 2%wt of phosphotungstic acid as catalyst, 20%wt of methanol as co-solvent during the reaction, reaction temperature at 90°C, ultrasound time for 10 min and H₂O₂/S molar ratio of 16, and ultrasound irradiation had the obvious reinforcement in oxidative desulfurization of diesel fuel.

Abstract: Sludge with large production is difficult to be dewatered without any pretreatment. Pretreatment with ultrasound and microwave can adjust the structure of sludge and change the water form, therefore increase the water content which could be dispelled easily. Dewaterability and morphological of sludge from sewage treatment plant including microwave and ultrasound were studied. Capillary Suction Time (CST), viscosity, Settle Volume (SV), water content, Chemical Oxygen Demand (COD), Zeta potential and morphological characteristics were tested. After microwave modification, the particle size of sludge ranged from 33.55μm to 28.98μm, and fractal dimension was about 2.8. Microscopic image analysis showed that the particle of sludge became coarse. After ultrasound modification, the particle size of sludge ranged from 33.55μm to 9.44μm, fractal dimension was about 2.9. Thus, the smaller particles were observed after ultrasound. The gray associate degree coefficient of viscosity and moisture content is the bigest. Through the analysis of dewatering characteristics of sludge and water content, a model which contributes to predict moisture content of sludge online was established.