• Polymer(Korea)
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• v.26 no.3
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• pp.353-359
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• 2002

High intensity ultrasound has been applied to a series of poly(ethylene oxide) (PEO)/water systems having different molecular weights of PEO. Major interest was focused on the effect of ultrasonic wane on the melt viscosity chemical structure and thermal properties of PEO. The expected role of ultrasound used in this study was to generate macroradicals of PEO chains by the formation and subsequent collapse of bubbles. It was found that the melt viscosity and chemical structure of PEO change significantly depending on the sonication time. For the prolonged sonication, PEO chains were significantly degraded and new end groups were formed by the interplay of various radical species. When the molecular weight of PEO was relatively higher, the crystallization rate was decreased and the intensity of the melting peak was reduced.

• Journal of the Korean Society of Radiology
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• v.9 no.7
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• pp.509-513
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• 2015

In this study, we evaluated the thermal denaturation characteristics of reusable NIPAM tissue mimicking (TM) Phantom by measuring the thermal sensitivity. And the changes of acoustic characteristic and thermal denaturation shape in NIPAM TM phantom according to the number of re-use time and re-use period were observed. With the result, as the sonication time is increased, the sound velocity of NIPAM phantom was decreased by 100 m/s and the attenuation was increased slightly. However, the changes according to the re-use period was not observed. In the thermal denaturation shape and size observation by ultrasound sonicaton, the remarkable changes have not been confirmed. With the result of this study, NIPAM Phantom was considered appropriate to evaluate and predict the effect of therapeutic ultrasound by in repeated sonication test.

• Toxicological Research
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• v.28 no.4
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• pp.209-216
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• 2012

The biological activity of particles is largely dependent on their size in biological systems. Dispersion in the aqueous phase has been both a critical impediment to and a prerequisite for particle studies. Carbon black has been used as a surrogate to investigate the biological effects of carbonaceous particles. Here, biocompatible methods were established to disperse carbon black into ultrafine and fine particles which are generally distinguished by the small size of 100 nm. Carbon black with a distinct particle size, N330 and N990 were suspended in blood plasma, cell culture media, Krebs-Ringer's solution (KR), or physiological salt solution (PSS). Large clumps were observed in all dispersion preparations; however, sonication improved dispersion - averaged particle sizes for N330 and N990 were $85.0{\pm}42.9$ and $112.4{\pm}67.9$ nm, respectively, in plasma; the corresponding sizes in culture media were $84.8{\pm}38.4$ and $164.1{\pm}77.8$ nm. However, sonication was not enough to disperse N330 less than 100 nm in either KR or PSS. Application of Tween 80 along with sonication reduced the size of N330 to less than 100 nm, and dispersed N990 larger than 100 nm ($73.6{\pm}28.8$ and $80.1{\pm}30.0$ nm for N330 and $349.5{\pm}161.8$ and $399.8{\pm}181.1$ nm for N990 in KR and PSS, respectively). In contrast, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) exhibited little effect. Electron microscopy confirmed the typical aciniform structure of the carbon arrays; however, zeta potential measurement failed to explain the dispersibility of carbon black. The methods established in this study could disperse carbon black into ultrafine and fine particles, and may serve as a useful model for the study of particle toxicity, particularly size-related effects.

• Carbon letters
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• v.19
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• pp.23-31
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• 2016

Carbon rich fly ash was recently reported to have compositions that are ideal for use as a precursor and catalyst for carbon nanotube growth. This fly ash powder is mostly composed of pure carbon, predominantly present as sp². In this work, the effect of sonication time on the morphology and structural properties of carbon rich fly ash particles is reported. The obtained results show that ultrasound treatment is an effective tool for producing ultrafine particles/fragments with higher porosity, which might be suitable for the adsorption of gasses. Moreover, carbon nanoparticles (CNPs) of this fly ash were produced in parallel using the ball milling technique, and were evaluated as reinforcements for epoxy based composites. These CNPs have almost spherical shapes with particle sizes of around 30 nm. They were found to have strong C=O carbonyl group bonds, which might be generated during the ball milling process. The tensile testing results of a fly ash CNP reinforced epoxy composite showed significant improvements in the mechanical properties, mainly in the stiffness of the polymer. The stiffness value was increased by around 23% of that of neat epoxy. These CNPs with chemically active groups might also be useful for other applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.3
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• pp.794-799
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• 2008

The effect of ultrasonication on the sulforaphane analysis in cruciferous vegetables was investigated by GC/MS. The ultrasonication of the analysis samples was carried out in dichloromethane as a solvent, which was followed by concentration in nitrogen gas, and the analysis of sulforaphane was performed using selective ion monitoring (SIM) at m/z 72, 160, 55 and 114. The content of sulforaphane was the highest in the extract of broccoli (149 ppm), and followed by cabbage (67.9 ppm) and radish (35.4 ppm). When the vegetable samples were shaked after ultrasonication, the extraction efficiency of sulforaphane was 2.7-fold enhanced, compared to the extraction by shaking. The result suggested that pretreatment including sonication can be used fer improving the extraction efficiency of sulforaphane.

• Analytical Science and Technology
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• v.35 no.5
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• pp.197-204
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• 2022

A gas chromatography-mass spectrometric method was developed for determining 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT), 2-methyl-4-isothiazolin-3-one (MIT), 1,2-benzisothiazolin-3-one (BIT), 3-iodo-2-propynyl butyl carbamic acid (IPBC) and benzoic acid (BA) in household products. A 0.5 g sample was placed in a test tube and dissolved with 5 mL water, 5 mL methylene chloride and 1.0 mL methanol. The solution was extracted by ultra-sonication followed by mechanical shaking using the salting out effect. Under the established condition, the lowest quantification limits of all analytes were in the range of 0.04-10 mg/kg and their relative standard deviations were less than 8.0 %. The method was used to analyze 10 household products. As a result of analyzing 10 household products, MIT was detected in the range of 1.2-3.5 mg/kg in 3 of 10 samples, CMIT was detected in the range of 2.6-8.2 mg/kg in 3 of 10 samples, and BA was detected in the range of 5.0-15 mg/kg in 4 of 10 samples. Meanwhile, BIT and IPBC were not detected in any of the products. It has been shown that this method can be used for the simultaneous determination of biocides with various physical and chemical properties in household products.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.10
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• pp.1114-1122
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• 2005

This research investigates the effects of sonication mode, reaction temperature and volume on sonolysis of 1,4-dioxane in order to increase the degradation efficiency and kinetics. The degradation efficiency in case with pulse mode was about 10 % higher than that in case with continuous mode. The degradation profiles in both cases, which were performed without the control of reaction temperature and in 1000 mL, were composed of three steps. However, 1,4-D was mainly degraded in the initiation step as the first portion and the acceleration step as the second portion. The initial step agreed with zero-order expression well, while the acceleration step could be fitted with pseudo 1st-order expression. The kinetic model in case with $5^{\circ}C$ and 300 mL conformed to pseudo 1st-order, while that in cases with $10^{\circ}C$ to $40^{\circ}C$ agreed with zero-order expression. The degradation efficiency and profile of 1,4-D in the experiment with $20^{\circ}C$ and 300 mL was higher and simpler than that in case with $20^{\circ}C$ and 1000 mL. The reaction temperature and volume influence bubble intensity, which was produced in sonication. The increase of bubble intensity induced to augment the production of OH radical in sonication.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.945-948
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• 2008

Nanocomposite materials provides efficient reinforcement, thermal endurance, and many other advantages depending on the additives used, with applications in the aerospace, automotive, and biomedical industries. Here, epoxy based nanocomposites were synthesized in the presence of Cloisite 15A and characterized with TEM, XRD, TGA, and DMA. To determine the effect of the clay d-spacing, Cloisite 20A was also used to synthesize the nanocompostes. In addition to the traditional hot plate method, an ultrasonicator was used to investigate the effect of different types of mixing on the properties of the nanocomposite; no significant effect was found. An examination of the nanocomposite morphology revealed that all the nanocomposites synthesized yielded an intercalated structure. When 5 wt% of Cloisite 15A was used with 20 min sonication time, the storage modulus increased 10% over the neat(no clay) nanocomposite. In general, the presence of Cloisite 15A produced a better storage modulus than Cloisite 20A.

• Journal of the Korean Applied Science and Technology
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• v.28 no.3
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• pp.313-320
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• 2011

Encapsulation of L-ascorbic acid(AA) into BGsome was attempted to improve its stability. BGsome is a bio-compatible vesicular system prepared by dispersion of hydrated liquid crystalline phase formed through hydration of 1,3-butylene glycol(BG)-dissolved lecithin with an aqueous solution containing hydrophilic component. The characteristics of AA encapsulated BGsome, such as droplet size, surface charge, and solution appearance, was investigated. The concentration of AA solution had considerable effect on droplet size and surface charge of BGsome. Several tens nanometer droplet made by sonication treatment did not showed any change of size with storage time. Stability of AA was improved by encapsulation into BGsome, which was verified through DPPH test and HPLC assay.

• Steel and Composite Structures
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• v.17 no.6
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• pp.825-834
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• 2014

This manuscript presents an experimental investigation on the effect of Multi-walled carbon nanotubes (MWCNTs) addition on the tensile, flexural and impact properties of woven Kevlar fabric reinforced epoxy composites. MWCNTs were dispersed in the epoxy resin by sonication technique and the samples were fabricated by hand layup laminating procedure. Scanning electron microscopy (SEM) was used to characterize the microstructure of produced samples. The effects of adding small amounts (${\leq}1%$) of MWCNT on the tensile, flexural and impact (Izod) behaviors of laminated composites were analyzed. Results revealed that MWCNTs enhanced the Young's modulus up to 20%, bending modulus up to 40%, and impact strength up to 45% in comparison with woven Kevlar fabric/epoxy composites. It was found that the maximum improvements in mechanical properties were happened for 0.5 wt.% MWCNT.