• Title/Summary/Keyword: wet milling

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Preparation and characteristics of modified Ni/YSZ cermet for high temperature electrolysis (고온 수전해 전극용 modified Ni/YSZ cermet 제조 및 전극특성)

  • Chae, Ui-Seok;Park, Geun-Man;Hong, Hyeon-Seon;Choo, Soo-Tae;Yun, Yongseung
    • Journal of Hydrogen and New Energy
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    • v.15 no.2
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    • pp.98-107
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    • 2004
  • Modified Ni/YSZ cermets for high temperature electrolysis were synthesized by dry or wet mechanical alloying methods. The Ni/YSZ composit particle was directly fabricated from the ball milling of Ni and YSZ powder or obtained from the reduction of NiO/YSZ particle after the ball milling of NiO and YSZ. In the case of the NiO/YSZ composite particle, the dry milling increased the average particle size whereas the wet milling decreased the size. The dry milling showed that fine YSZ particles were distributed over large Ni surfaces while Ni and YSZ particles similar in size were well mixed in the wet milling method. These features were the same in the Ni/YSZ composite particle prepared from Ni and YSZ powders. The electrical conductivity of the wet-milled Ni/YSZ cermet showed the highest value of $2{\times}10^2S/cm$ among the specimens and this value was increased to $1.4\times10^4S/cm$ after the sintering at $900^\circ{C}$ for 1 h.

Bread-making Properties of Rice Flours Produced by Dry, Wet and Semi-wet Milling (건식, 습식 및 반습식 쌀가루에 의한 쌀빵의 특성 비교)

  • Lee, Myung-Hee;Lee, Young-Tack
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.35 no.7
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    • pp.886-890
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    • 2006
  • Rice flours produced by dry, wet, and semi-wet milling methods were used to investigate bread-making properties. Wet milled rice flours were produced by two different steeping temperatures of $25^{\circ}C$ and $55^{\circ}C$, properties of composite flour containing 70% rice flour and 30% wheat flour with the addition of vital wheat gluten were tested. Among rice flours, wet milled rice flour showed increased mixing time and dough stability determined by a mixograph. Wet milled rice flours produced higher loaf volume compared with dry of semi-wet milled rice flours. Wet-milled rice flour steeped at $55^{\circ}C$ appeared to produce good rice breads with relatively high loaf volume. Crumb hardness of bread prepared with wet milled rice flour was lower than the other breads and increased slowly during 3-day storage at $25^{\circ}C$.

The Specficity of Phase Transitions of Lead Monoxide (산화납의 특이상전이)

  • 김정욱;최성철;이응상
    • Journal of the Korean Ceramic Society
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    • v.30 no.8
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    • pp.623-628
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    • 1993
  • Lead monoxide has two phases at room temperature. One is a yellow orthorhombic phase, the other is a redtetragonal phase. Sometimes two phases are hybrided. The specificity of phase transitions of lead oxide is found during the milling of the batch including lead oxide. The pure orthorhombic phase of PbO can be transformed to the tetragonal phase perfectly by wet ball milling (milling liquid is distilled water) without thermal energy. However, when ethyl alcohol, isopropyl alcohol and aceton are used as milling liquid, respectively, the hybrid form of orthorhombic andtetragonal phases is obtained by wet ball milling. From the hybrid form heat-treated at $600^{\circ}C$ for 3hrs, this work results that mechanical phase transition of orthorhombic phase make a new form as distorted type orthorhombic phase of PbO.

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Synthesis of Cathode Material-Nickel Sulfides by Mechanical Alloying for Sodium Batteries

  • Liu, Xiaojing;Ahn, Hyo-Jun;Ahn, In-Shup
    • Journal of Powder Materials
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    • v.19 no.3
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    • pp.182-188
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    • 2012
  • In this study, fine cathode materials $Ni_3S_2$ and $NiS_2$ were synthesized using the simple, convenient process of mechanical alloying (MA). In order to improve the cell properties, wet milling processes were conducted using low-energy ball milling to decrease the mean particle size of both materials. The cells of Na/$Ni_3S_2$ and Na/$NiS_2$ show a high initial discharge capacity of 425 mAh/g and 577 mAh/g respectively using wet milled powder particles, which is much larger than commercial ones, providing some potential as new cathode materials for rechargeable sodium-ion batteries.

Synthesis of cathode material for sodium ion batteries using dry vibration milling (건식 진동밀을 이용한 나트륨이온전지 양극활물질 합성)

  • Lee, Yeon-Woo;Kim, Han-Jun;Kang, Yeonhui;Kim, Chang-Sam
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.27 no.2
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    • pp.70-74
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    • 2017
  • Two milling methods, dry vibration milling and wet ball milling, were used to prepare $Na_{2/3}(Ni_{1/3}Mn_{2/3})O_2$ powders as a cathode material for sodium ion batteries. The morphology and electrochemical property of the two powders with different milling processes were compared to each other. The particle size is less than $1{\mu}m$ in the dry vibration milled powder, while lots of larger particles than $1{\mu}m$ were found in the wet ball milled one. The single phase of $Na_{2/3}(Ni_{1/3}Mn_{2/3})O_2$ was obtained in the temperature range of $875{\sim}900^{\circ}C$. The discharge capacity and discharge voltage of the powder prepared by the dry process were higher than those of one prepared by the wet process.

Preparation of Lignocellulose Nanofibers from Korean White Pine and Its Application to Polyurethane Nanocomposite (국산 잣나무 유래 리그노셀룰로오스 나노섬유 제조 및 이를 이용한 강화 폴리우레탄 나노복합재료)

  • Jang, Jae-Hyuk;Lee, Seung-Hwan;Kim, Nam-Hun
    • Journal of the Korean Wood Science and Technology
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    • v.42 no.6
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    • pp.700-707
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    • 2014
  • The effect of steam and ozone pretreatments on fibrillation efficiency by wet disk-milling was investigated. Hemicellulose (40%) and lignin (42%) of Korean white pine were partially removed by steam and ozone pretreatments, respectively. With increasing wet disk-milling time, the diameter of fibers was significantly decreased and its size distribution became narrow. Especially, the average diameters of lignocellulose nanofibers after steam and ozone pretreatments were 19 nm and 12 nm, respectively. Thus-obtained lignocellulose nanofibers-reinforced polyurethane composite was prepared. Tensile strength and elastic modulus were drastically improved with increasing wet disk-milling time and lignocellulose nanofiber content. Nanocomposite reinforced by lignocellulose nanofibers after two pretreatments showed higher tensile properties, compared to that reinforced by lignocellulose nanofiber without pretreatment, at the similar wet disk-milling time.

Effect of Wet Milling on Scum Generation and Solubilization in Batch Ozone Reaction Using Digested Sludge (소화슬러지를 이용한 회분식 오존반응 시 습식분쇄가 스컴 생성과 가용화에 미치는 영향)

  • Hong, Seong-Min;Lee, Dong-Hoon;Kim, Choong-Gon;Shin, Hyun-Gon
    • Journal of the Korea Organic Resources Recycling Association
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    • v.27 no.2
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    • pp.13-18
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    • 2019
  • Sewage sludge treatment is increasing every year due to improvement of living and urbanization. However, interest in anaerobic digestion which is one of the recycling technology. There is anaerobic digestion of increasing due to limitations of ocean dumping and final disposal. But, the limit of anaerobic digestion efficiency due to the advanced treatment of sewage has been limited, and studies for solubilization technology have been actively conducted. Therefore, in this study, we aimed to investigate the variation of generation of scum and the solubilization efficiency in the application of pre-treatment of ozone reaction and the change of properties of digested sludge with wet milling. There are results of VS/TS increased by 4.4% and $SCOD_{cr}/TCOD_{cr}$ increased by 9.4% by wet milling alone. In addition, the increase of the specific surface area due to which the reduction of the particle size of the solid content of the sludge in the ozone reaction caused by wet milling decreased the generation rate of scum at 14.3% and increased VS/TS at 2.1%, compared with the ozone reaction alone. From these results, it is expected that the application of wet milling can be increased the contact efficiency with solids in the sludge during ozone reaction with suppress scum and increase the efficiency of the subsequent process in anaerobic digestion.

The Effect of Wet Milling on Transparency of Transparent Dielectric in PDP

  • Han, Sun-Mi;Park, Ji-Su;Hwang, Jong-Hee;Lim, Tae-Young;Kim, Kwang-Jin;Masaki, Takaki
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.558-560
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    • 2004
  • We report the effect of wet ball milling conditions on the transparency of glass frit. Generally, the particle size of glass frit decreased as the milling time increased. And the transparency of glass frit changed with the particle size variation. The transparency of glass frit A increased as the milling time increased. But, the transparency of glass frit B, containing high $B_2O_3$ decreased as the particle size decreased. It seems to be the result of chemical reaction with water and glass frit.

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Microstructural Characteristics of Ni/YSZ Cermet for High Temperature Electrolysis by Mechanical Alloying (기계적 합금화법으로 제조된 고온 수전해용 Ni/YSZ 전극의 미세구조 특성)

  • Park Keun-Man;Chae Ui-Seok;Hong Hyun Seon;Choo Soo-Tae
    • Korean Journal of Materials Research
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    • v.14 no.10
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    • pp.743-748
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    • 2004
  • Modified Ni/YSZ cermets for high temperature electrolysis were synthesized by the direct ball milling of Ni and YSZ powder. The ball milling was carried out in dry process and in ethanol with varying milling time. While the dry-milling decreased the average size from 65 to $80{\mu}m$, the wet-milling decreased the average size down to $10{\mu}m$. In addition, very fine particles less than $0.1{\mu}m$ were observed in the wet-milling condition. The subsequent process of cold-pressing and sintering at $900^{\circ}C$ for 2 h did not affect the particle size of dry-milled powder. The electrical conductivity of the dry-milled Ni/YSZ cermet showed the value of $5{\times}10^{2}\;S/cm$ and this value was increased to $1.4{\times}10^{4}\;S/cm$ after the sintering at $900^{\circ}C$ for 2 h.

Comparison of rice flour properties of different cultivars using wet and dry milling processes

  • Park, Jiyoung;Lee, Seuk-Ki;Park, Hye-Young;Choi, Hye-Sun;Cho, Dong-Hwa;Han, Sang-Ik;Lee, Kyung Ha;Oh, Sea-Kwan
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2017.06a
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    • pp.286-286
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    • 2017
  • We conducted to compare the characteristics of rice flours according to the different milling processes. Five rice varieties (Oryza sativa L.) with different amylose content were prepared by wet and dry milling processes. The moisture contents of wet-milled rice flours (WMR) was mostly three-time higher than those of dry-milled flours (DMR). Water absorption index (WAI), water solubility index (WSI) and swelling power (SP) increased in proportion to temperature ($50-90^{\circ}C$). WAI, WSI, SP of DMR showed higher value than those of WMR. Baeokchal (BOC) which is waxy rice cultivar was significantly high level of WSI. Pasting properties of DMR except BOC cultivar resulted in higher peak viscosity, trough viscosity, final viscosity and Setback. The levels of resistant starch in the four cultivars except Dodamssal (DDS) were under 1% irrespective of Milling processes, whereas the resistant starch contents of DMR and WMR in DDS was 9.18 and 6.27, respectively. Damaged starch content of WMR were less than those of DMR, moreover, negative correlation was observed between amylose content and damaged starch of rice cultivars. These results suggest that the properties of rice flour varied depending on the milling methods and varieties, and it could be a reference for selecting the appropriate processing purposes.

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