• Title/Summary/Keyword: Grind

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A Study on the Dressing Time of AI2O3 Grinding Wheel in Surface Grinding by Laser Beam (평면연삭 가공시 레이저 빔을 이용한 $AI_2O_3$ 계 연삭숫돌의 드레싱시기에 관한 연구)

  • 김희남
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1995.03a
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    • pp.17-23
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    • 1995
  • This paper describes investigation of the dressing time by laser in the surface grinding operation. Always dressing work is done before grinding operation. And then generates wear and roading on the wheel by contact between the grinding performance but also ground surfaces. On these states dressing work is needed. On this paper contour of the wheel by He-Ne laser is measured. It has also been found that the wheel deflection reduces the actual depth of cut and the roughness of the ground surface.

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Development of Discontinuous Grinding Wheel with Multi-Porous Grooves (다기공홈형 단속연삭지석의 개발에 관한 연구)

  • 김정두
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1996.03a
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    • pp.108-113
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    • 1996
  • Conventionally, grinding of stainless steel, aluminium alloy, copper alloy, and titanum alloy is difficult due to the mechanical properties such as low hardness, high toughness which result in the loading of wheel and the poor surface finish. In order to grind this sort of materials easily, discontinuous grinding wheel with multi-porous grooves was newly developed. The multi-porous grooves were formed during wheel production. This discontinuous grinding wheel drastically increases the grinding performance. It is desirable to use the discontinuous grinding wheel when grinding materials with high efficiency and accuracy which is impossible by conventional wheels. In this paper, the construction and manufacturing method of grinding wheel with multi-porous grooves are explained. The grinding charateristics of discontinuous grinding wheel was also illustrated.

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An Experimental Study on the Turning Machinability of Machinable Ceramics (Machinable Ceramics 의 가공 성능 평가를 위한 실험적 연구)

  • Gang, Jae-Hun;Lee, Jae-Gyeong
    • 한국기계연구소 소보
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    • s.20
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    • pp.79-87
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    • 1990
  • Advanced ceramics have some excellent properties as the material for the mechanical component. It is, however, very difficult to grind ceramics with high efficiency because of their high strength, hardness and brittleness. Thus it is required also by a strong boom of demands for development of Machinable ceramics with high machinability in the most of industries. In present research, experiments are carried out to compare the machinability of sample Machinable ceramics. A $\ell$N(Aluminum Nitride) with additives of BN(Boron Nitride), yttrium. CaO are turned with cut-off tool type tungsten carbide bite using conventional turning machine.

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A Study on High Efficiency Dressing of Diamond Grinding Wheel (다이야몬드 숫돌의 고능률 Dressing 에 관한 연구)

  • Choi, Kyoung-Il;Kang, Jae-Hoon;Jung, Yoon-Gyo
    • Journal of the Korean Society for Precision Engineering
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    • v.8 no.2
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    • pp.106-113
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    • 1991
  • A diamond grinding wheel is generally used to grind hard and brittle materials, such as advanced ceramics. It is, however, quite difficult to dress a diamond grinding wheel efficiently because of its high degree of hardness. In this study, some investigations are carried out to increase dressing efficiecy of resinoid bonded diamond grinding wheel. Dressing forces are measured over a wide range of dressing conditions, and SEM observation of a grinding wheel is carried out. Special attention is paid to comparison between stick method and rotary brake method. Results obtained in this study provide useful information determining reguired dressing time, and for choosing efficient dressing condition for diamond grinding wheel.

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Grinding Characteristic of Advanced Ceramics (파인세라믹의 연삭가공특성)

  • Jung, Yoon-Gyo;Kang, Jae-Hoon
    • Journal of the Korean Society for Precision Engineering
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    • v.7 no.2
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    • pp.105-112
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    • 1990
  • Advanced ceramics have some excellent properities as the material for the mechanical component. It is, however, very difficult to grind ceramics with high efficiency because of their high strength, hardness and brittleness. In this paper, some experiments are carried out to find the basic grinding characteristic of advanced ceramics. Representative advanced ceramics, such as AL/sub 2/ O/sub 3/, ZrO/sub 2/, SiC and Si/sub 3/N/sub 4/and ground with diamond wheels. Special attention is paid to comparison between the conventional and creep feed grinding. Results obtained in this study provide some useful informations to attain the high efficiency grinding of advanced ceramics.

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A Study on the Bending and Compressive Strength of Mortar using Waste Calcium Material as a Filling Material (폐칼슘 재료를 채움재로 사용한 모르타르의 휨·압축강도에 관한 연구)

  • Kim, Han-Nah;Kim, Bong Joo;Jung, Ui In;Seo, Eun-Seok;Hong, Sang Hun;Shin, Dong Uk
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2020.06a
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    • pp.64-65
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    • 2020
  • Oyster shells are difficult to grind, while oyster shell powders have coarse and coarse grains, whereas egg shell powder, the same high calcium material, has small and soft particles and has opposing properties. In order to study the change in flexural and compressive strength by designing different mixing ratios using 50% of oyster shell powder and egg shell powder as a filling material. As a result of the experiment, there is almost no difference in the result.

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Effect of High-Protein Korean Malting Barley on Malt Quality (한국산 고단백질 맥주보리가 맥아 품질에 미치는 영향)

  • Kim, Kwan-Bae;Kang, Kook-Hee
    • Korean Journal of Food Science and Technology
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    • v.34 no.3
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    • pp.407-412
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    • 2002
  • This study was carried out to investigate the differences in malt quality between high-protein Korean malting barley and low-protein Korean malting barley. The average protein content of each area in the 1996 crops was as follows; The protein content of Doosan-29 from Jeon-Nam was 14.1% (d.b), that of Sacheon-6 from kyung-Nam was 13.4% (d.b) and that of Doosan-8 from Je-Ju was 12.8% (d.b). In the micro malting trial for high and low protein malting barley, the original protein level of the malting barley was not changed and decreased during germination days. The malt friability of high-protein malting barley was very low, but that of low-protein malting barley was high. The malt friability of high-protein malting barley was 44.5% and that of low-protein malting barley was 84.2%. In proportion to an increase of +1% (d.b) in barley protein, the fine grind extract of malt was decreased -0.86% (d.b). Economically, it was the most negative factor for high-protein Korean malting barley. The ${\beta}-glucan$ content of high-protein malting barley was higher than that of low-protein malting barley. Wort viscosity and malt color were increased and Kolbach index was decreased in high-protein malting barley. Free amino nitrogen and diastatic power for high-protein malting barley were higher than those of low-protein malting barley. They were the most positive factors for high-protein Korean malting barley.

Beauty activity of extracts from Saurus chinensis by ultra-fine ground (초미세 분쇄한 삼백초(Saurus chinensis) 추출물의 미용 활성)

  • Park, Hye-Jin;Park, Ki-Tae;Hong, Shin-Hyub;Kim, Na-Hyun;Park, Mi-Jeong;Hong, Eun-Jin;Ahn, Dong-Hyun;An, Bong-Jeun;Cho, Young-Je
    • Food Science and Preservation
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    • v.23 no.6
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    • pp.899-905
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    • 2016
  • In this study, beauty food activities were determined for extracts of Saurus chinensis as functional beauty food. Tyrosinase inhibitory effect was increased as more 4 folds by ultra-fine grind technology than normal grind technology in ethanol extracts from Saurus chinensis. A ultra-fine ground technology was used to increase the extraction yield for bioactive compounds from medicinal plants. Tyrosinase inhibitory activity, which is related to skin-whitening, was confirmed to be 100% for ethanol extracts at 1,000 ppm of phenolics. Anti-wrinkle activity was determined showing 30% of inhibition effect at above 1,000 ppm phenolic concentration. The elastase inhibitory activity of water and ethanol extracts from ultra-fine ground Saurus chinensis showed higher inhibition activity than compared to extracts from normal ground Saurus chinensis. Astringent activity in ethanol extracts was determined showing over 70% at 250 ppm of phenolics. Based on these results, Saurus chinensis extracts can be used as a functional beauty food and cosmetic with whitening, anti-wrinkle and pore contraction effects.

Hyaluronidase inhibitory activity of extracted phenolic compounds from ultrafine grind Saururus chinensis (초미세 분쇄한 삼백초로부터 추출된 phenolic 화합물의 hyaluronidase 억제 효과)

  • Park, Ki-Tae;Oh, Sang-Lyong;Cho, Young-Je
    • Food Science and Preservation
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    • v.23 no.1
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    • pp.20-26
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    • 2016
  • In this study, the anti-inflammatory effect of hyaluronidase (HAase) inhibition was determined from 92 species of oriental herbal medicine extracted with water and ethanol solvents because of their non-toxicity in the human body. The water extracts of Evodia officinalis (86.8%), Thuja orientalis (80.8%), Carthami semen (66.5%), Melia azedarach (74.7%), Siegesbeckia pubescens (61.3%), Saururus chinensis (49.15%) showed a relatively greater anti-inflammatory activity. The ethanol extracts of Ailanthus altissima and Saururus chinensis demonstrated the highest anti-inflammatory effect at above 90%. Saururus chinensis was selected for its high anti-inflammatory effect in both water and ethanol extract. Ethanol was more effective than water and optimal extraction conditions for phenolic compounds was determined to be extraction with 50% ethanol for 12 hours. The extracts from Saururus chinensis in optimal condition showed 70~80% anti-inflammatory effect when $100{\sim}250{\mu}g/mL$ phenolic concentration was treated. Concentration of above $500{\mu}g/mL$ decreased the inhibitory effect. The anti-inflammatory effect and extraction yield were increased by ultra-fine grind technology, indicating that this method can be used to increase the extraction yield of phenolic compounds from medicinal plants.

Effect of Garlic on Lipids of Low Salted Anchovy during Fermentation (마늘의 첨가가 저염 멸치젓의 숙성 중 지질성분에 미치는 영향)

  • Kwon, O-Chen;Shin, Jung-Hye;Sung, Nak-Ju
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.34 no.3
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    • pp.420-426
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    • 2005
  • In this study, anchovy were prepared with two different salt concentration of 20% and 10% which added 2, 5, 8 and 10% of grind garlic (LAS 1, 2, 3, 4) and garlic juice (LSB 1, 2, 3, 4), respectively. The experimental samples were fermented during 30, 60, 90, 110 days, which were analyzed pH, peroxide value, TBARS (thiobarbituric acid reactive substances) and fatty acid. pH increased as fermentation-period goes by. 110th day of fermentation, pH was neutralized at pH 6.2-6.7. Peroxide value in the 10% salt added groups reach the highest point at 60 days fermentation, and then decreased during its fermentation. TBARS increased until 90 days fermentation and then decreased remarkably in all groups. At 90 days fermentation, TBARS contents were 13.0 and 14.4 MA (㎎/㎏) in 10% grind garlic added group (LSA4) and 10% garlic juice added group (LSB4), respectively. The major composition of fatty acids were 16:0, 18:1, 16:1,20:5, 20:6 and 14:0, in order. These fatty acids were 80% of total fatty acids. The fatty acid composition ratio was little increased and decreased during fermentation period, and polyunsaturated fatty acid decreased a little at 110 days.