Effect of Ultrasonic Power on the Microstructure and Properties of 304 Stainless Steel Welded Joints Through Cold Metal Transfer Welding Assisted with Ultrasonication

Fei Li,Furong Chen,Peihu Gao,Wei Wang,Chenlong Yang,Shiyuan Liu 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.10

With the development of welding technology, low heat input and high efficiency cold metal transfer welding have become the main methods of thin plate welding. However, low heat input easily forms columnar crystals, which will endanger the mechanical properties of joints. Therefore, ultrasonication treatment was applied to the cold metal transfer welding of 304 stainless steel to conduct cold metal transfer welding assisted with ultrasonication in this paper. The comparison between cold metal transfer welding assisted with ultrasonication and cold metal transfer showed that the weld grain diameter obtained by cold metal transfer welding assisted with ultrasonication was finer. In the welded joint, the maximum grain size diameter of the weld seam in cold metal transfer welding assisted with ultrasonication decreased to 375 μm, and the maximum tensile strength of cold metal transfer welding assisted with ultrasonication increased to 734 MPa. The texture intensity of the weld seam in cold metal transfer was significantly greater than that of the weld seam in cold metal transfer welding assisted with ultrasonication, which was ascribed to the improvement of the microstructure of the weld seam in cold metal transfer welding assisted with ultrasonication. In cold metal transfer welding assisted with ultrasonication, the flow performance of the welding pool increased, and the ultrasonic cavitation degree was intensified. This resulted in the significant refinement of the weld grain, the reduction of texture intensity, and an increase in the tensile strength.

CuY zeolite catalysts prepared by ultrasonication-assisted ion-exchange for oxidative carbonylation of methanol to dimethyl carbonate

Woo, Je-Min,Seo, Jung Yoon,Kim, Hyunuk,Lee, Dong-Ho,Park, Young Cheol,Yi, Chang-Keun,Park, Yeong Seong,Moon, Jong-Ho Elsevier 2018 Ultrasonics sonochemistry Vol.44 No.-

<P><B>Abstract</B></P> <P>The influence of ultrasonication treatment on the catalytic performance of CuY zeolite catalysts was investigated for the liquid-phase oxidative carbonylation of methanol to dimethyl carbonate (DMC). The deammoniation method of NH<SUB>4</SUB>Y into HY zeolites was optimized and characterized by elemental analyzer, derivative thermogravimetry, Brunauer–Emmett–Teller (BET) analyzer, and powder X-ray diffractometry, revealing that the HY zeolite deammoniated at 400 °C presented the highest surface area, complete ammonium/proton ion exchange, and no structure collapse, rendering it the best support from all the prepared zeolites. CuY zeolites were prepared via aqueous phase ion exchange with the aid of ultrasonication. Upon ultrasonication, the Cu<SUP>+</SUP> active centers were uniformly dispersed in the Y zeolites, penetrating the core of the zeolite particles in a very short time. In addition to enhancing the Cu dispersity, the ultrasonication treatment influenced the BET surface area, acid amount, Cu<SUP>+</SUP>/Cu<SUP>2+</SUP> ratio, and also had a relatively small impact on the Cu loading. Consequently, adequate exposure to ultrasonication was able to increase the conversion rate of methanol into dimethyl carbonate up to 11.4% with a comparable DMC selectivity of 23.7%. This methanol conversion is 2.65 times higher than that obtained without the ultrasonication treatment.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CuY zeolite catalysts were prepared by ultrasonication-assisted ion exchange. </LI> <LI> The ultrasonication treatment improved surface area, acidity and Cu dispersity. </LI> <LI> The enhanced Cu dispersity increased the ratio of active Cu<SUP>+</SUP> species. </LI> <LI> The obtained catalysts showed better performance for DMC synthesis via oxidative carbonylation. </LI> </UL> </P>

초음파 조사에 의한 토양내 중금속 추출 기작 연구

신연준,이차돌,유종찬,양중석,김호섭,백기태,Shin, Yeon-Jun,Lee, Cha-Dol,Yoo, Jong-Chan,Yan, Jung-Seok,Kim, Ho-Sub,Baek, Kitae 한국지하수토양환경학회 2015 지하수토양환경 Vol.20 No.1

In this study, the mechanisms on ultrasonication enhanced metals extraction were investigated compared with the conventional washing technique. We hypothesized the mechanisms on enhanced extraction of ultrasonication: ultrasonication increased the temperature of soil slurry and decreased average particle size of soil due to breakdown of soil aggregate. Actually, the ultrasonication increased the temperature of soil slurry to $60^{\circ}C$ in this study, and the increase in the temperature enhanced the metal extraction to 15-20% even in the conventional simple mixing. The conventional washing technique decreased average size of soil particles because of breakdown of soil aggregate, and the ultrasonication decreased the size more than that of washing. The breakdown of soil aggregate improved the contact between metals and washing agent, which enhanced the extraction of metals in the ultrasonication. Therefore, we concluded that the main mechanisms of ultrasonication are increase in the temperature and breakdown of the soil aggregate. Finally, the ultrasonicaiton increased the extractability of metals upto 40% compared to conventional washing technique.

마이크로파와 초음파가 키틴 추출시간에 미치는 영향

권기남 ( Ki Nam Kwon ),최희숙 ( Hee Sook Choi ),차보숙 ( Bo Sook Cha ) 한국식품영양학회 2009 韓國食品營養學會誌 Vol.22 No.1

Effects of microwave and ultrasonication on chitin extraction time were investigated in this study. Chitin was extracted from ground crab shell by demineralization in 1.0 N HCl solution at 25℃ with or without ultrasonication and deproteinization in 1.0 NaOH solution at 100℃ without ultrasonication and at 70℃ with ultrasonication. Microwave treatment was also used for deproteinization with 5 min heating and 5 min standing without microwave. The changes in color difference, the contents of ash, calcium and nitrogen were measured during demineralization and deproteinization. Ultrasonication of 4 hr in 1.0 N HCl solution for removal of calcium and 1.5 hr of microwave heating in 1.0 N NaOH for deproteinization corresponded to 6 hr in 0.1 N HCl and 2 hr in 1.0 N NaOH of heating at 100℃ without those treatments, respectively. The data obtained showed that these treatments were effective reduction of chitin extraction time by 25~33% for chitin preparation. The chitin obtained from these ultrasonication and microwave treatments resulted 0.55% of ash, 0.25% of calcium, 2.47% of nitrogen and 20.64% of yield ratio. Those treatments selected were also reduced the darkness development time of the chitin solution during demineralization and deproteinization.

Ultrasonic-assisted sol-gel method of preparation of TiO₂ nano-particles: Characterization, properties and 4-chlorophenol removal application

Neppolian, B.,Wang, Q.,Jung, H.,Choi, H. Elsevier 2008 Ultrasonics sonochemistry Vol.15 No.4

<P><B>Abstract</B></P> <P>Nano-size TiO<SUB>2</SUB> photocatalysts were prepared by sol-gel and ultrasonic-assisted sol-gel methods using two different sources of ultrasonicator, i.e., a bath type and tip type. The physicochemical characteristics of the catalysts were investigated by BET, XRD and TEM analyses and the photocatalytic properties of the TiO<SUB>2</SUB> catalysts prepared by three different methods were compared. The intrinsic and extrinsic properties of TiO<SUB>2</SUB>, such as the particle size, surface area, pore-volume, pore-diameter, crystallinity as well as anatase, rutile and brookite phase ratios, could be controlled by the ultrasonic-assisted sol-gel method. During this preparation method, the effect of such important operating variables as the ultrasonic irradiation time, power density, the ultrasonic sources (bath-type and tip-type), magnetic stirring during synthesis, initial temperatures and size of the reactors are discussed here. It was found that each of the parameters played a significant role in controlling the properties of the TiO<SUB>2</SUB> nano-particles. Among the three different methods, TiO<SUB>2</SUB> photocatalysts prepared by ultrasonic (tip-US) assisted sol-gel possessed the smallest particle size, highest surface area and highest pore-volume than the catalysts prepared by the other two methods. 4-Chlorophenol was used as a pollutant to observe the photocatalytic degradation ability of the prepared photocatalysts and the TiO<SUB>2</SUB> catalysts prepared by the bath-US ultrasonic-assisted sol-gel method were shown to be the most highly active. This is due to their high surface area and high pore-diameter. This study clearly demonstrates the importance and advantages of ultrasonication in the modification and improvement of the photocatalytic properties of mesoporous nano-size TiO<SUB>2</SUB> particles.</P>

The Effect of Ultrasonication on the Micro-splitting of Wool Fiber

Bae, Chang Hyun,Um, In Chul 한국섬유공학회 2012 Fibers and polymers Vol.13 No.7

In this study, normal and dichlorodicyanuric acid (DCCA)-treated wool slivers were ultrasonicated in formic acid aqueous solutions. The effect of the ultrasonication condition on the wool fiber splitting was examined and the mechanism of the splitting by ultrasonication in formic acid was elucidated. No wool fiber splitting occurred at formic acid content up to 70 %, but the fiber splitting accelerated as the formic acid content increased from 75 %. Although no fiber splitting occurred up to 450W ultrasonic power, the degree of splitting increased significantly with increasing ultrasonic power above 450W. The wool fiber splitting by ultrasonication was heterogeneous and FE-SEM observations revealed a three-step splitting process: 1) full removal of scale, 2) removal of cell membrane complex (CMC), and 3) fiber splitting. A comparison of the fiber splitting of normal and DCCA-treated wool revealed that the scale of the ultrasonication-treated wool was removed by peeling off rather than by dissolution.

Optimization of Electric Field-assisted Ultrasonication for Disintegration of Waste Activated Sludge

( Kyung-won Jung ),( Tae-un Jeong ),( Min-jung Cha ),( Kyu-hong Ahn ) 한국폐기물자원순환학회(구 한국폐기물학회) 2014 한국폐기물자원순환학회 심포지움 Vol.2014 No.1

In the present study, an electric field is applied in order to disintegrate waste activated sludge (WAS). As a preliminary step, feasibility tests are investigated using different applied voltages of 10 to 100 V for 60 min. As the applied voltage increases, the disintegration degrees (DD) are gradually enhanced, thereby the soluble N, P, and carbohydrate concentrations increase simultaneously due to the protein decomposition. Subsequently, an optimization process is conducted using response surface methodology with a Box-Behnken design (BBD). The total solid concentration, applied voltage, and reaction time are selected as independent variables, while the DD is selected as the response variable. The overall results demonstrate that the BBD with an experimental design can be useed effectively in the optimization of the electric field treatment of WAS. In the confirmation test, a DD of 10.26±0.14% is recorded, which corresponds to 99.1% of the predicted response value under the statistically optimized conditions. Finally, the statistic optimization of the combined treatment (electric field + ultrasonication) showed that even though this is limited to highly disintegrated WAS when being applied individually, a high DD of 47.28±0.20% was recorded where the TS concentration was 6,780 mg/l, the strength of ultrasonication was 8.0 W, the applied voltage was 68.4 V, and the reaction time was 44 min. E-SEM images clearly revealed that the application of the electric field is a significant alternative method for the combined treatment of WAS, and this is first attempt to increase disintegration using electric field for combined treatment with ultrasonication.

Ultrasonication Assistance Increases the Efficiency of Isoflavones Extraction from Kudzu (Pueraria lobata Ohwi) Roots Waste

Kyu Hyuk Kwun,Geun-Joong Kim,신현재 한국생물공학회 2009 Biotechnology and Bioprocess Engineering Vol.14 No.3

This study assesses the use of ultrasonication to improve the extraction process of classical solvent extraction methods for extracting isoflavones from the kudzu roots waste. The kudzu roots waste was produced after squeezing fresh kudzu roots to make juice. The effects of extraction time, extraction temperature, ultrasonic power, and ethanol concentration in ethanol/ water mixtures were investigated. The extraction yield was found to increase with extraction time and temperature. The application of ultrasonication-assisted extraction (UAE) increased the extraction yield of water/ethanol mixture (20:80) at 25°C 3 fold. A maximum amount (7.28 g) of isoflavone was obtained from 100 g of dried kudzu roots waste by UAE with water/ ethanol mixture (20:80) for 6 h at 80°C. Combining the use of ultrasonication with conventional vacuum evaporation method also reduced the concentration time for extracts from 45 to 24 min

Enhanced anaerobic digestion of livestock waste by ultrasonication: A tool for ammonia removal and solubilization

조시경,Mo-Kwon Lee,김동훈,Yeo-Myeong Yun,Kyung-Won Jung,신항식,오세은 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.4

Ultrasonication was applied to lower the ammonia level in livestock waste to enhance the anaerobic digestionperformance. In simulated waste tests, in spite of an identical temperature increase, a higher ammonia removalrate was observed at lower frequency. This could be explained by the existence of athermal effects, accounting for 64%of the total ammonia removal rate. These effects originated from various convections (micro-streaming, micro-convection,shock-waves, and micro-jets), possibly caused by stable bubbles, and this indigenous mixing ability led to anegligible effect of aeration in the ultrasound assisted ammonia stripping process. In actual waste tests, an ammoniaremoval rate of up to 55% was achieved with a 0.77 h−1 mass transfer rate coefficient. After ultrasonication (28 kHz,pH 11, 15 min) of livestock waste, 58% higher CH4 yield was achieved due to the decrease of ammonia concentration(28%) and enhanced solubilization (51%).

Ultrasonication-assisted extraction of resveratrol from grapes

Cho, Yong-Jin,Hong, Ji-Young,Chun, Hyang Sook,Lee, Sang Kook,Min, Hye-Young Elsevier 2006 Journal of food engineering Vol.77 No.3

<P><B>Abstract</B></P> <P>In order to search an effective extraction of resveratrol from grapes, superior to a conventional solvent extraction, an ultrasonication-assisted method was explored. When the new extraction of resveratrol was applied to fruit stem of <I>Campbell</I> and <I>Gerbong</I> grapes, the recovery yield was increased by 24–30%, compared to that by the conventional solvent extraction with ethanol/water (80:20%, v/v) maintained at 60°C for 30min. The ultrasonication-assisted extraction of resveratrol was modeled by the first-order reaction kinetics with reaction rate constants for extraction and degradation of resveratrol. For fruit stem of <I>Campbell</I> grape, the reaction rate constants <I>k</I> <SUB>1</SUB> and <I>k</I> <SUB>2</SUB> for extraction and degradation of resveratrol were 0.7797min<SUP>−1</SUP> and 0.06481min<SUP>−1</SUP>, respectively, while the parameters for fruit stem of <I>Gerbong</I> grape were 0.4773min<SUP>−1</SUP> and 0.03713min<SUP>−1</SUP>. In spite of the difference between two cultivars, the ratio of <I>k</I> <SUB>1</SUB> to <I>k</I> <SUB>2</SUB> was about 12 for both the cultivars. In simulation with the models for extraction and degradation of resveratrol, the maximum recovery of resveratrol from fruit stem of <I>Campbell</I> grape was 489.4μg/g-dry material at the extraction time of 3.48min. For the same time, the amount of compounds degraded from the extracted resveratrol was 83.1μg/g-dry material. These figures indicated 79.8% and 13.6% of the total resveratrol in fruit stem of <I>Campbell</I> grape. Similarly, the maximum recovery of resveratrol for fruit stem of <I>Gerbong</I> grape and the amount of degraded compounds were 80.6% and 13.1%, respectively, of the total resveratrol, which were calculated with 194.8μg/g-dry material and 31.6μg/g-dry material.</P>