• Journal of the Korean Applied Science and Technology
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• v.25 no.3
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• pp.395-403
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• 2008

In this study, the characteristics of emulsified fuel were studied. The emulsified fuel which was composed of water and diesel was manufactured by using homogenizer and ultrasonic generator. The more the percentage of water contents increases, the more the density increases to the emulsified fuel. However, the viscosity increased in the 60% of water contents and decreased in the 70% of water contents because the O/W type was formed. The 3 minutes's ultrasonic waves during the irradiation time was appropriate of 16,000 rpm. And the energy density of ultrasonic waves was 87.5J/g. The emulsion stability has improved in the lower temperature, the lower percentage of water contents, and the most stable emulsion state was obtained from 20%(w/w) of water contents. Also, the emulsion stability was related to the HLB values of emulsifiers. Especially, the HLB values of emulsifier were appropriate from 4 to 7 values.

• Korean Chemical Engineering Research
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• v.45 no.5
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• pp.460-465
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• 2007

Endosulfan-${\alpha}$ endosulfan-${\beta}$ and endosulfan-sulfate, which are classified as pesticides, were degraded by use of UV energy and ultrasonic irradiation. The degradation residuals were analysed by gas chromatography with an electron capture detector and TOC (total oragnic carbon) analysis. The reactions were conducted in a quartz annular reactor equipped with a low pressure mercury multilamp (8Wx2) and a sonic generator. All the aqueous solutions were concentrated as 10 mg/L initially. Endosulfans were degraded each to result in 48.2% (${\alpha}$), 50.0% (${\beta}$) and 76.5% (sulfate) of removal efficiency by UV energy, and 66.9% (${\alpha}$), 55.8% (${\beta}$) and 72.7% (sulfate) by ultrasonic irradiation, respectively. In contrast to the results of the single-component solutions, degradation of the endosulfan-sulfate was greatly suppressed to result in the lowest degradation rate and removal efficiency in the three-component solutions. This finding suggests that there should be a reversible reaction with a substantially low equilibrium constant between endosulfan-${\alpha}$ or -${\beta}$ and -sulfate in the coexistence of the three endosulfans. TOC data showed the endosulfans were decomposed by 20%~40% toward complete mineralization, producing a quantity of intermediates induced by the radical reactions. We found that all the decay reactions considered in this study nicely fell into pseudo first-order rate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.380-389
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• 2020

The conversion characteristics and fuel properties for producing biodiesel (BD) by blending beef-tallow, an animal waste resource with a high-saturated fatty acid content, and sunflower-oil, a vegetable oil with a high-unsaturated fatty acid content, were investigated. For this investigation, the effects of the control factors, such as the oil-blend ratio and methanol-to-oil molar ratio, on the fatty acid methyl ester and BD production yield were also investigated. The kinematic viscosity reduction effects of BD using heating and ultrasonic irradiation were verified, and the optimal temperature of each BD-diesel fuel blend for reducing the kinematic viscosity was derived using the correlation equation. As a result, the optimal conditions for producing blended biodiesel were verified to be TASU7 and a methanol-to-oil molar ratio of 10:1. The analysis results of the fuel properties of TASU7 satisfied the BD quality standard; hence, the viability of BD blended with waste tallow as fuel was verified. The experimental results on the kinematic viscosity reduction showed that heating is more effective in reducing the kinematic viscosity because it took less time than ultrasonic irradiation, and the equipment was cheaper and more straightforward than the ultrasonic irradiation method.

• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.663-669
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• 2018

The process of extracting active ingredients from wheat sprout using ultrasound assisted method was optimized with a central composite design model. The response value of the central composite design model established the extraction yield and the total flavonoids content, main effects and interactive effects were analyzed depending on independent variables such as the extraction time, volume ratio of ethanol to ultrapure water, and ultrasonic irradiation power. The volume ratio of ethanol to ultrapure water and ultrasonic irradiation power were relatively large for the extraction yield and the extraction time was most significantly affected the total flavonoids, Considering both the extraction yield and total flavonoids content, the optimal extraction conditions were as follows: the extraction time of 17.00 min, volume ratio of ethanol to ultrapure water of 50.25 vol%, ultrasonic irradiation power of 551.70 W. In this case, the extraction yield and total flavonoids content were 28.43 wt% and $29.99{\mu}g\;QE/mL\;dw$, respectively. The actual experimental extraction yield and total flavonoids content under this condition were 8.73 wt% and $29.65{\mu}g\;QE/mL\;dw$, respectively with respective error rates of 1.05 and 1.13%.

• Journal of the Korean Chemical Society
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• v.55 no.5
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• pp.776-780
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• 2011

A mild and efficient procedure for the synthesis of various 1,5-benzothiazepines were developed. This method provides an easy access for preparation of 1,5-benzothiazepine derivatives in the presence of 10 mol% catalyst of CAN under ultrasonic irradiation. This method provided clean conversion, mild reaction condition, no use of toxic solvent and shorter reaction time compared to other reported method.

• Environmental Engineering Research
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• v.24 no.2
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• pp.191-201
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• 2019

Petroleum industry produces one of the popular hazardous waste known as Petroleum Sludge. The treatment and disposal of petroleum sludge has created a major challenge in recent years. This review provides insights into various approaches involved in the treatment, and disposal of petroleum sludge. Various methods used in the treatment and disposal of petroleum sludge such as incineration, stabilization/solidification, oxidation, and bio-degradation are explained fully and other techniques utilized in oil recovery from petroleum sludge such as solvent extraction, centrifugation, surfactant EOR, freeze/thaw, pyrolysis, microwave irradiation, electro-kinetic method, ultrasonic irradiation and froth flotation were discussed. The pros and cons of these methods were critically considered and a recommendation for economically useful alternatives to disposal of this unfriendly material was presented.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2195-2205
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• 2023

One of the salient nuclear fuel performance parameters for new fuel types under development is changes in fuel thickness. To test the new commercially fabricated U-10Mo monolithic plate-type fuel, an irradiation experiment was designed that consisted of multiple mini-plate capsules distributed within the Advanced Test Reactor (ATR) core, the mini-plate 1 (MP-1) experiment. Each capsule contains eight mini-plates that were either fueled or "dummy" plates. Fuel thickness changes within a fuel assembly can be characterized by measuring the gaps between the plates ultrasonically. The channel gap probe (CGP) system is designed to measure the gaps between the plates and will provide information that supports qualification of U-10Mo monolithic fuel. This study will discuss the design and the results from the use of a custom-designed CGP system for characterizing the gaps between mini-plates within the MP-1 capsules. To ensure accurate and repeatable data, acceptance and calibration procedures have been developed. Unfortunately, there is no "gold" standard measurement to compare to CGP measurements. An effort was made to use plate thickness obtained from post-irradiation measurements to derive channel gap estimates for comparison with the CGP characterization.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.3
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• pp.191-204
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• 2019

The 20-kHz ultrasonic irradiation was applied to investigate bacterial inactivation and antibiotic susceptibility changes over time. Applied intensities of ultrasound power were varied at 27.7 W and 39.1 W by changing the amplitude 20 to 40 to three bacteria species (Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus). By 15-min irradiation, E. coli, a gram-negative bacterium, showed 1.2- to 1.6-log removals, while the gram-positive bacteria, Enterococcus faecalis and Staphylococcus aureus, showed below 0.5-log removal efficiencies. Antibiotic susceptibility of penicillin-family showed a dramatic increase at E. coli, but for other antibiotic families showed no significant changes in susceptibility. Gram-positive bacteria showed no significant differences in their antibiotic susceptibilities after ultrasound irradiation. Bacterial re-survival and antibiotic susceptibility changes were measured by incubating the ultrasound-irradiated samples. After 24-hour incubation, it was found that all of three bacteria were repropagated to the 2- to 3-log greater than the initial points, and antibiotic inhibition zones were reduced compared to ones of the initial points, meaning that antibiotic resistances were also recovered. Pearson correlations between bacterial inactivation and antibiotic susceptibility showed negative relation for gram-negative bacteria, E. coli., and no significant relations between bacterial re-survival and its inhibition zone. As a preliminary study, further researches are necessary to find practical and effective conditions to achieve bacteria inactivation.

• Journal of the Korean Society of Radiology
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• v.12 no.3
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• pp.427-433
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• 2018

Because of the expectation of the non-invasive treatment effect, Various studies on the treatment of varicose veins using focused ultrasound are reported. In this study, the bio-tissue phantom and tissue equivalent phantom that can be applied to estimation of ultrasonic varicose veins treatment effect. Each phantom was evaluated for its usefulness by evaluating the acoustic characteristics and the shrinkage rate according to the ultrasonic irradiation. A multi-layer structure phantom with three layers of skin, fat, and muscle was constructed considering the structure of the tissue where the varicose veins occurred. The materials constituting each layer were made to have characteristics similar to human body. In addition, the multi-layered phantoms with blood vessel mimic tube, with bovine blood vessel, and with animal tissue were fabricated. The degree of shrinkage of blood vessel mimic material and vascular tissue according to ultrasonic irradiation was evaluated using B-mode image. As the results of this study, it was thought that the proposed phantom could be used effectively in the evaluation of ultrasonic varicose veins treatment. In addition, it is thought that these phantoms could be applied to the development of varicose vein treatment device using the focused ultrasound and the verification of the therapeutic effect.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.2
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• pp.207-215
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• 2006

This study evaluated the effect of ultrasonic irradiation on reducing membrane fouling for the treatment of chemically treated leachate and biologically treated leachate. The experiments on improvement of membrane flux according to the membrane types(MF and UF) and membrane materials were performed with changing frequency(40 kHz and 120 kHz) and intensity(200 W and 400 W) of ultrasound in ultrasonic membrane separation apparatus which ultrasound can be periodically irradiated. Additionally, the effect of dual frequency ultrasound which 40 kHz md 120 kHz are irradiated simultaneously was evaluated. The improvement of membrane flux by periodical ultrasound irradiation was higher in microfiltration(MF) membrane than in ultrafiltration(UF) membrane. It was sustained more in the MF membrane of polyvinylidene fluoride(PVDF) than in that of polysulfon(PS). Ultrasonic improvement of membrane flux was different depending on the characteristics of target wastewater. It was sustainably maintained without reclogging using dual frequency ultrasound although the improvement of membrane flux was lower.