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Study on Cooling Characteristic Improvement in Underwater Wet Arc Welding of TMCP Steelplate (TMCP강의 습식수중 아크용접부의 냉각특성 개선에 관한 연구)

  • 김민남
    • Journal of Ocean Engineering and Technology
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    • v.6 no.2
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    • pp.113-124
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    • 1992
  • The offshore industry created a need for quality wet weld repairs. Wet welding is a fast method of repair providing sound, structural quality welds. It requires less support equipment than a similar underwater dry weld repair or the alternative mechanical connections. Compared to welds made in air, underwater wet welds are plagued by increased hardness due to rapid quenching by the surrounding water. In this paper is described the experimntal study of improving the cooling rates of wet welds of TMCP steel plate by shielding around weld arc surroundings. The principal results of this experimental investigation can be summarized as follows : By shielding around weld arc surrounding, the cooling rates resulting from wet welds on TMCP steel plate could be lower than that of nonshielded wet welds and the fesibility on high quality of mecanical properties of wet weld on TMCP steel plate was carried out with shielded weld arc surrounding.

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Water Droplet Ejection Characteristics of a Wet Porous Point-Plate Airgap (다공성 수침-평판전극간의 수적 방출 특성)

  • Jung, Jae-Seung;Lee, Woo-Seok;Moon, Jae-Duk
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.10
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    • pp.2005-2010
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    • 2009
  • Water droplet ejection characteristics of a point-to-plate airgap, with a wet porous point as a corona electrode, has been investigated. And the water droplet traces, charge, mass and number were measured experimentally. More particles are observed with wet porous point than metal point because the corona-discharging wet porous point can eject a number of water droplets. The water droplets ejected from the positive-corona-discharging wet porous point showed very fine traces as compared with those from the negative-corona-discharging wet porous point. Moreover, the water droplets ejected from the AC-corona-discharging wet porous point showed granular-like larger traces. It was shown that the weak corona discharge can eject smaller water droplets with larger ratio of mass-to-charge than the intense corona discharge.

Effects of Wet Feeding of Diets with or without Food Waste on Growth Performance and Carcass Characteristics in Finishing Pigs

  • Moon, J.S.;Kwon, I.K.;Chae, B.J.
    • Asian-Australasian Journal of Animal Sciences
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    • v.17 no.4
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    • pp.504-510
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    • 2004
  • Two experiments were conducted. In expt. 1, a total of fifty-four pigs (L$\times$Y$\times$D, 56.14$\pm$1.7 kg) were used for a feeding trial to determine the effect of wet feeding of a commercial-type diet without food waste (FW). Treatments were dry (Control), wet (WF) and wet+dry feeding (WDF). For wet feeding, the diet was mixed with water at a ratio of 1:2.5 (feed:water). A wet feed was given during the whole experimental period for the WF group, but the dry feed was given during the finisher period for the WDF group. In expt. 2, a total of fifty-four pigs(L$\times$Y$\times$D, 55.7$\pm$1.8 kg) were used for a feeding trial to determine the effect of wet feeding of FW. Treatments were a commercial-type dry (Control), wet fermented food waste (WFFW) and WFFW+dry feeding (WFFW+DF). For wet feeding of fermented food waste, however, some ingredients (concentrate) were added to make nutrient contents comparable to the control diet. The FW collected was ground ($\leq$5 mm), heated with a steam jacket (140$\pm$3$^{\circ}C$) and fermented with probiotics for one day in a steel container at 30-40$^{\circ}C$. For the WFFW group, the wet feed was given during the whole experimental period, but a dry feed was given during finisher period for the WFFW+DF group. In expt. 1, during the grower period, pigs fed wet feed showed higher average daily gain (ADG) and feed conversion ratio (FCR) than those fed only dry feed (p<0.05). During the finisher period, pigs in the WDF group showed better ADG and FCR than the control group. During the entire experimental period, pigs in the WDF group grew faster (p<0.05) than those in the control group, and the same trend was found in FCR. Also, dressing percentage, backfat thickness, lean %, and pork color were not affected by the wet feeding of diets in this study. In expt. 2, during the grower period, pigs fed diets containing FW showed lower (p<0.05) ADG than those fed the control diet. But FCR was better (p<0.05) in pigs fed FW than in the control group. During the finisher period, pigs in the WFFW+DF group grew faster (p<0.05) than those in the control and WFFW groups. During the entire experimental period, pigs fed the control diet showed better ADG (p<0.05) than those fed FW, but feed intake and FCR were vice versa. Dressing percentage was lower (p<0.05) in the WFFW than in the control group, but backfat was thinner in the WFFW group than in the control group. In summary, it can be concluded that wet feeding of formula feed can improve daily gain, however, feeding fermented wet food waste may reduce daily gain of finishing pigs, even though it was fermented and the nutrient was fortified with concentrates. In addition, dry feeding of a formula feed during the finishing period can improve daily gain in pigs fed a wet feed with or without food waste during the grower period.

Knowledge of Nocturnal Emissions in Late Elementary School Boys in Incheon (일지역 후기 학령기 남자 아동의 몽정에 대한 지식 정도)

  • Lee, Yong-Hwa
    • Korean Parent-Child Health Journal
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    • v.12 no.1
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    • pp.77-87
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    • 2009
  • Purpose: The purpose of this study was to determine the knowledge of nocturnal emissions, or wet dreams and to provide information for developing a wet dream education program for elementary school boys. Method: The research design was a descriptive study through questionnaires. Data was collected from May 10, 2009 to May 20, 2009. A total of 197 late elementary school boys in Incheon, Korea participated in this study. Data was analyzed using the SPSS WIN 15.0 program. Result: The results of this study were as follows; Knowledge of wet dreams in late elementary school boys was low; The mean of the information about wet dreams was 14.00 on a 100 point scale; There were significant differences of knowledge regarding wet dreams according to the educational experience at 6 items and wet dreams experience at 12 items of total 21 items. This indicates that present education for wet dreams is not efficient and does not provide appropriate information when they need practical information. Conclusion: Self education learning program for wet dreams should be developed for late elementary school boys which includes different contents and time required for further study, evaluation and assessment.

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ITO Wet Etch Properties in an In-line Wet Etch/Cleaning System by using an Alternating Movement of Substrate (기판의 왕복 운동을 이용한 인라인 식각세정장치 내 ITO 식각특성)

  • Hong, Sung-Jae;Kwon, Sang-Jik;Cho, Eou-Sik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.21 no.8
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    • pp.715-718
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    • 2008
  • An in-line wet etch/cleaning system was established for the research and development in wet etch process. The system was equipped with a reverse moving system for the reduction in the size of the in-line wet etch/cleaning system and it was possible for the glass substrate to be moved back and forth and alternated in a wet etch bath. For the comparison of the effect of the normal motion and that of the alternating motion on the in-line wet etch process, indium tin oxide(ITO) pattern was obtained through both wet etch process conditions. The results showed that the alternating motion is not inferior to the normal motion in etch rate and in etch uniformity. It is concluded that the alternating motion is possible to be applied to the in-line etch process.

Development of Continuous Cross-Flow Rice Drying Model and Drying Speed Control System Using Fuzzy Logic(II) - Drying Speed Control - (벼의 횡류 연속식 건조 모델 개발과 퍼지논리를 이용한 건조 속도 제어에 관한 연구(II) - 건조속도제어 -)

  • 송대빈;고학균;조성인
    • Journal of Biosystems Engineering
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    • v.23 no.5
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    • pp.457-464
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    • 1998
  • A drying speed control system using fuzzy logic was developed in order to minimize the damage of rice quality for a large capacity continuous dryer. The performance of the system was tested at two object moisture content of 17% and 25% on a wet basis. For object moisture content of 17% on a wet basis, the final output moisture contents from 20.46%, 20.96%, 18.98% on a wet basis were 17.99%, 17.6% and 17.23% on a wet basis, respectively. For object moisture content of 25% on a wet basis, the final output moisture contents from 28.85%, 26.95%, 28.11%, 27.8% on a wet basis were 25.24%, 24.9%, 25.23% and 25.09% on a wet basis, respectively.

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Thermodynamic and Aerodynamic Meanline Analysis of Wet Compression in a Centrifugal Compressor

  • Kang, Jeong-Seek;Cha, Bong-Jun;Yang, Soo-Seok
    • Journal of Mechanical Science and Technology
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    • v.20 no.9
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    • pp.1475-1482
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    • 2006
  • Wet compression means the injection of water droplets into the compressor of gas turbines. This method decreases the compression work and increases the turbine output by decreasing the compressor exit temperature through the evaporation of water droplets inside the compressor. Researches on wet compression, up to now, have been focused on the thermodynamic analysis of wet compression where the decrease in exit flow temperature and compression work is demonstrated. This paper provides thermodynamic and aerodynamic analysis on wet compression in a centrifugal compressor for a microturbine. The meanline dry compression performance analysis of centrifugal compressor is coupled with the thermodynamic equation of wet compression to get the meanline performance of wet compression. The most influencing parameter in the analysis is the evaporative rate of water droplets. It is found that the impeller exit flow temperature and compression work decreases as the evaporative rate increases. And the exit flow angle decreases as the evaporative rate increases.

Design of Single-wafer Wet Etching Bath for Silicon Wafer Etching (실리콘 웨이퍼 습식 식각장치 설계 및 공정개발)

  • Kim, Jae Hwan;Lee, Yongil;Hong, Sang Jeen
    • Journal of the Semiconductor & Display Technology
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    • v.19 no.2
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    • pp.77-81
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    • 2020
  • Silicon wafer etching in micro electro mechanical systems (MEMS) fabrication is challenging to form 3-D structures. Well known Si-wet etch of silicon employs potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAH) and sodium hydroxide (NaOH). However, the existing silicon wet etching process has a fatal disadvantage that etching of the back side of the wafer is hard to avoid. In this study, a wet etching bath for 150 mm wafers was designed to prevent back-side etching of silicon wafer, and we demonstrated the optimized process recipe to have anisotropic wet etching of silicon wafer without any damage on the backside. We also presented the design of wet bath for 300 mm wafer processing as a promising process development.

Physicochemical and microbial characteristics of longissimus lumborum and biceps femoris muscles in Korean native black goat with wet-aging time

  • Ali, Mahabbat;Park, Ji-Young;Lee, Seong-Yun;Choi, Young-Sun;Nam, Ki-Chang
    • Journal of Animal Science and Technology
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    • v.63 no.1
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    • pp.149-159
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    • 2021
  • This study examined the effects of different wet-aging times on the physicochemical characteristics and microbial profile of longissimus lumborum (LL) and biceps femoris (BF) muscles from Korean native black goat (KNBG) meat. The water holding capacity (WHC), pH, cooking loss, shear force, meat color, free amino acid, total bacteria, and coliform count of KNGB meat were analyzed at 0, 5, 10, and 15 days of wet-aging at 4℃ under vacuum packaging. The results showed that different wet-aging times led to significant pH variations between the muscles throughout the aging period. The wet-aging time did not affect the WHC and cooking loss in meat from the LL muscle. In the BF muscle, however, meat wet-aged for five days had a significantly higher WHC and less cooking loss than meat aged for 0, 10, and 15 days. The meat from the LL muscle wet-aged for five days produced tenderer meat (low shear force value) than the unaged meat (p < 0.05). Moreover, the color was similar in the LL muscle regardless of the number of aging days. In the BF muscle, the redness (a*) was higher in the meat wet-aged for 15 days compared to that aged for 0, 5, and 10 days (p < 0.05). Regardless of the muscles, an increase in wet-aging time led to an increase in the total free amino acids contents in both muscles (p < 0.05). On the other hand, the tasty/bitter amino acid ratio was significantly higher for five days of wet-aged meat than 10 and 15 days of aging from the BF muscle. In addition, regardless of the muscles, the total bacteria and coliform counts were significantly lower for five days of wet-aged meat than 10 and 15 days of aging (p < 0.05). Therefore, chevon wet-aged for five days is an optimal aging period under vacuum packaging that fortifies meat quality with a minimal microbial negative defect.

ITO Patterning of an In-line Wet Etch/Cleaning System by using a Reverse Moving Control System (반송제어모드를 이용한 인라인 식각/세정장치의 ITO 전극형성기술)

  • Hong, Sung-Jae;Im, Seoung-Hyeok;Han, Hyung-Seok;Kwon, Sang-Jik;Cho, Eou-Sik
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.4
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    • pp.327-331
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    • 2008
  • An in-line wet etch/cleaning system was established for the research and development in wet etch process as a formation of electrode such as metal or transparent conductive oxide layer. A reverse moving system was equipped in the in-line wet etch/cleaning system for the alternating motion of glass substrate in a wet etch bath of the system. Therefore, it was possible for the glass substrate to be moved back and forth and it was possible to reduce the size of the system by using the reversing moving system. For the effect of the alternating motion of substrate on the etch rate in the in-line wet etch bath, indium tin oxide(ITO) patterns were obtained through wet etch process in the in-line system in which the substrate was moved back and forth. From the CD(critical dimension) skews resulted from the ADI CD and ACI CD of the ITO patterns, it was concluded that the alternating motion of glass substrate are possible to be applied to the mass production of wet etch process.