• Title/Summary/Keyword: Milling time

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Quality Characteristics of Wheat Flour suitable for Wet Noodle (생면용에 적합한 밀가루의 품질 특성)

  • Shin, Eun-Ju;Kim, Nam-Geun;Chung, Chang-Ho;Kim, Hyo-Suk
    • Korean journal of food and cookery science
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    • v.30 no.5
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    • pp.540-546
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    • 2014
  • This study was conducted to compare the commercial noodle flours (n=8) of each milling company in Korea. Eight noodle flour samples were classified into two types of flours, all-purpose flour (AF, n=4) and premium noodle flour (PF, n=4) and tested using general component analysis. Texture assessment and sensory test for doughs and noodles were performed. The dough strength was positively correlated with lower ash content, smaller particle size and longer formation time. Sensory evaluation found that weaker cooked noodle strength correlated with higher scores in preference and softness. As a result, it can be suggested that PF is better than AF in noodle making because PF has lower ash content and smaller particle size than AF. As such, flour characteristics that produce noodle flour of uniform quality can be obtained by combining flours with the above processing characteristics to fit the qualities desired.

Synthesis of ferromagnetic Sm-Fe-N powders subjected to mechanochemical reaction (Mechanochemical Reaction에 의한 Sm-Fe-N계 자성분말의 합성)

  • 이충효;최종건;김판채
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.10 no.4
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    • pp.292-296
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    • 2000
  • Mechenochemical reaction by planetary type ball mill is applied to prepare $Sm_2$$Fe_{17}$$N_{x}$ permanent magnet powders. Starting from pure samarium and iron powders, the formation process of hard magnetic $Sm_2$$Fe_{17}$$N_{x}$ phase by ball milling and a subsequent solid state reaction were studied. At as-milled stage powders were found to consist of amorphous Sm-Fe and $\alpha$-Fe phases in all composition of $Sm_2$$Fe_{100-x}$(x = 11, 13, 15). The dependence of starting composition of elemental powder on the formation of Sm-Fe intermetallic compound was investigated by heat treatment of as-milled powders. When Sm concentration was 15 at%, heat-treated powder consists of mostly $Sm_2$$Fe_{17}$$N_{x}$single phase. For synthesizing of hard magnetic $Sm_2$$Fe_{17}$$N_{x}$ compound, additional nitriding treatment was carried out under $N_2$gas atmosphere at $450^{\circ}C$. The increase in the coercivity and remanence was parallel to the nitrogen content which increased drastically at first and then gradually as the nitriding time was extended. The ball-milled Sm-Fe-N powders were expected to be prospective materials for synthesizing of permanent magnet with high performance.

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Grinding Kinetics of Calcite, Pyrophyllite and Talc During Stirred Ball Milling - Consideration of Selection Function (교반 볼밀에 의한 방해석, 납석, 활석의 분쇄 시 분쇄속도론에 관한 연구 - 선택함수의 고찰)

  • Choi, Hee-Kyu;Kim, Seong-Soo;Hwang, Jin-Yeon
    • Journal of the Mineralogical Society of Korea
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    • v.20 no.2 s.52
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    • pp.135-145
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    • 2007
  • The needs for the ultra fine particles have been increased in preparation field of raw powders such as fine ceramics and high functional products. In this study, a series of wet grinding experiments were carried out on inorganic powders such as calcite, pyrophyllite and talc by a stirred ball mill. The particle size distribution of ground products of each test material fur a given grinding time was found to be expressed by the grinding rate (selection function) which was obtained from the grinding kinetics analysis. The median diameter decreased from 6.49 to $0.47{\mu}m$ in calcite, and decreased from 3.91 to $1.14{\mu}m$ in pyrophyllite. However, in talc, median diameter was decreased a little bit from 10.30 to $6.67{\mu}m$. The grinding rate changing on calcite and pyriphyllite were similar at the same conditions. However, in the case of talc, it was observed that the grinding rate was not increased compared to other samples.

Effect of h-BN Content on Microstructure and Mechanical Properties of AIN Ceramics (AIN 세라믹스의 미세조직과 기계적 성질에 미치는 h-BN 첨가의 영향)

  • 이영환;김준규;조원승;조명우;이은상;이재형
    • Journal of the Korean Ceramic Society
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    • v.40 no.9
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    • pp.874-880
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    • 2003
  • The effect of h-BN content on microstructure, mechanical properties, and machinability of AlN-BN based machinable ceramics were investigated. The relative density of sintered compact decreased with increasing h-BN content. The four-point flexural strength also decreased from 238 MPa of monolith up to 182 MPa by the addition of 30 vol% h-BN. Both low Young's modulus and residual tensile stress, formed by the thermal expansion coefficient difference between AIN and h-BN, might cause the strength drop in AlN-BN composite. The crack deflection, and pull-out phenomena increased by the plate-like h-BN. However, the fracture toughness decreased with h-BN content. The second phases, consisted of YAG and ${\gamma}$-Al$_2$O$_3$, were formed by the reaction between Al$_2$O$_3$ and Y$_2$O$_3$. During end-milling process, feed and thrust forces measured for AlN-(10~30) vol% BN composites decreased with increasing h-BN particles, showing excellent machinability. Also, irrespective of h-BN content, relatively good surfaces with roughness less than 0.5 m (Ra) could be achieved within short lapping time.

Preparation of Nanocomposite Metal Powders in Metal-Carbon System by Mechanical Alloying Process (기계적 합금화 방법에 의한 금속-카본계에서의 나노복합금속분말의 제조)

  • Kim, Hyun-Seung;Lee, Kwang-Min
    • Korean Journal of Materials Research
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    • v.8 no.4
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    • pp.328-336
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    • 1998
  • In metal-carbon system with no mutual solubility between matrix and alloying elements as solid or liquid phases, Cu-C-X nanocomposite metal powders were prepared by high energy ball milling for solid-lubricating bronze bearings. Elemental powder mixtures of Cu-lOwt.%C- 5wt. %Fe and Cu- lOwt. %C- 5wt. %Al were mechanically alloyed with an attritor in an argon atmosphere, and then microstructural evolution of the Cu-C-X nanocomposite metal powders was examined. It has been found that after 10 hours of MA, the approximately 10$\mu\textrm{m}$ sized Cu-C- X nanocomposite metal powders can be produced in both compositions. Morphological characteristics and microstructural evolution of the Cu-C-X powders have shown a similar MA procedure compared to those of metal-metal system. As a result of X - ray diffraction analysis, diffraction peaks of Cu and C were broaden and peak intensities were decreased as a function of MA time. Especially, the gradual disappearance of C peaks in the X- ray spectra is proved to be due to the lower atomic scattering factor of C. The calculated Cu crystallite sizes in Cu- C- X nanocomposite metal powders by Williamson- Hall equation were about lOnm size, on the other hand, the observed ones by TEM were in the range of 10 to 30nm.

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Characteristics of Recycled Aggregate Powder Containing Mortar Depending on Grinding Efficiency (분쇄 효율에 따른 순환골재 분말 혼입 모르타르의 특성)

  • Bang, Jinwook;Jang, Youngil;Lee, Jongwon;Mun, Seokho;Chu, Hyunseung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.23 no.2
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    • pp.116-121
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    • 2019
  • In order to evaluating applicability of RAP (recycled aggregate powder) in mortar, in this study, physical and mechanical tests was carried out. Material characteristics of recycled aggregate and RAP were evaluated and the mechanical properties of mortar replaced with RAP were analyzed. Test result of sieve analysis showed that as the milling time increased the fineness modulus was decreased and the distribution of 0.6 mm particle size was found to increase. The fluidity of mortar mixture substituted with RAP tended to increase than Plain mixture. It was result that the increasing fluidity was affected by unreacted surplus water in the mortar as the binder was replaced with RAP. From the compressive strength result of the mortar subjected to RAP, it was found that the RAP was able to replace up to about 10% of unit binder weight although the compressive strength of mortar was decreased as the RAP replacement increased. From the above study, it can be concluded that the physical properties of RAP satisfied the quality standard of aggregate for replacement with fine aggregate. Moreover, in case of the RAP was replaced up to 10% of unit cement weight, it was able to be possible to improve fluidity and compressive strength of mortar.

Changes in chemical characteristics of cellulase-treated wheat germ extract (효소 처리 밀 배아 추출물의 화학적 특성 변화)

  • Lee, Jae-Kang;Jang, Davin;Kang, Dongwoo;Lee, Jeonghoon;Kum, Hyeim;Choi, Yonghyoun;Kang, Hee;Choi, Yong-Seok;Kim, Dae-Ok
    • Korean Journal of Food Science and Technology
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    • v.51 no.2
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    • pp.97-102
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    • 2019
  • Wheat germ, which is rich in nutrients and phytochemicals, is a by-product during the milling process of wheat kernel. In this study, we aimed to increase the amount of bioactive 2,6-dimethoxy-1,4-benzoquinone (2,6-DMBQ) in wheat germ using the cell-wall-degrading enzyme cellulase (Celluclast 1.5L). The amounts of organic acids, free sugars, and 2,6-DMBQ in wheat germ treated with Celluclast 1.5L were evaluated at various reaction times and temperatures. The results of reversed-phase high-performance liquid chromatography of Celluclast 1.5L-treated wheat germ revealed 2,6-DMBQ, four organic acids (tartaric, acetic, lactic, and succinic acids), and three free sugars (sucrose, fructose, and glucose). As reaction time and temperature of the mixture of wheat germ and Celluclast 1.5L increased, the contents of four organic acids, glucose, fructose, and 2,6-DMBQ increased, but that of sucrose decreased. Taken together, these results suggest that Celluclast 1.5L-treated wheat germ containing increased amounts of 2,6-DMBQ serves as a source of functional ingredients in food industry.

Improvement of Pervaporative Water Flux of Mordenite Zeolite Membrane by Controlling Membrane Thickness (분리막 두께 조절에 의한 모데나이트 제올라이트 분리막의 투과증발 물 투과유속 증진 연구)

  • Yoon, Byung-jin;Kim, Young-mu;Lee, Du-Hyoung;Cho, Churl-Hee
    • Membrane Journal
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    • v.29 no.5
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    • pp.263-275
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    • 2019
  • In the present study, thickness of MOR zeolite membranes was controlled by changing seed size, seeding amount, and aging time of hydrothermal solution, and then effect of membrane thickness on pervaporative ethanol dehydration for 90 wt.% ethanol-water mixture was investigated. First, nanosize MOR zeolite seeds with a diameter of 20 to 30 nm was successfully prepared by planetary milling a laboratory synthesized MOR zeolites and the coating amount was controlled by seed concentration and infiltration volume of coating solution during vacuum-assisted seeding. As seeding amount decreased, membrane thickness was reduced up to around $4{\mu}m$. The MOR zeolite membrane having a thickness of $4{\mu}m$ showed a water/ethanol separation factor of 760 and water flux of $1.0kg/m^2h$. The excellent water flux was due to the reduced membrane thickness which was derived from the nanosize seed. Therefore, it could be concluded that membrane thickness control by using nanosize seed can be a crucial factor to improve pervaporative water flux of MOR zeolite membrane.

Fabrication of complete denture using 3D printing: a case report (3D 프린팅을 이용한 양악 총의치 제작 증례)

  • Lee, Eunsu;Park, Chan;Yun, Kwidug;Lim, Hyun-Pil;Park, Sangwon
    • The Journal of Korean Academy of Prosthodontics
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    • v.60 no.2
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    • pp.202-210
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    • 2022
  • Recently with the advance in digital dentistry, the fabrication of dentures using computer-aided design and computer-aided manufacturing (CAD-CAM) is on the rise. The denture designed through a CAD software can be produced in a 3-dimensional manufacturing process. This process includes a subtractive processing method such as milling and an additive processing method such as 3D printing and in which it can be applied efficiently in more complex structures. In this case, complete dentures were fabricated using Stereolithography (SLA)-based 3D printing to shorten the production time and interval of visits in patient with physical disabilities due to cerebral infarction. For definitive impression, the existing interim denture was digitally replicated and used as an individual tray. The definitive impression obtained with polyvinyl siloxane impression material was including information about the inclination and length of the maxillary anterior teeth, vertical dimension, and centric relation. In addition, facial scan data with interim denture was obtained so that it can be used as a reference in determination of the occlusal plane and in arrangement of artificial teeth during laboratory work. Artificial teeth were arranged through a CAD program, and a gingival festooning was performed. The definitive dentures were printed by SLA-based 3D printer using a FDA-approved liquid photocurable resin. The denture showed adequate retention, support, and stability, and results were satisfied functionally and aesthetically.

3D printed surveyed restoration and metal framework in removable dentures: A case report (3D 프린팅 된 서베이드 금관과 금속 프레임워크를 이용한 양악 가철성 의치 수복 증례)

  • Song Yi Park;Sang-Won Park;Chan Park;Woohyung Jang;Kwi-Dug Yun
    • The Journal of Korean Academy of Prosthodontics
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    • v.61 no.2
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    • pp.153-159
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    • 2023
  • Computer-aided design-computer-aided manufacturing technology has been widely used in the manufacture of fixed prostheses including implants, but in the case of removable dentures, the analog method is still being used due to the errors such as a lack of fusion and over-fusion in selective laser meting process. With the recent development of CAD software, virtual surveying and framework design are made possible, and the designed file can be manufactured by milling or 3D printing. It replace the analog method of waxing and denture curing process and also can reduce the production time and cost. Therefore, this case is reported because good clinical results were obtained by digitally surveying on CAD software to produce a surveyed metal restoration and framework on maxillary and mandibular removable dentures.