• Title/Summary/Keyword: dry time

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A Study on Real Time Control of Resin Transfer Molding (RTM 공정의 실시간 제어에 관한 연구)

  • 이도훈;박윤희;이우일;엄문광;변준형
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2003.10a
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    • pp.79-82
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    • 2003
  • In case of performing resin transfer molding (RTM), race track effects and non-uniform fiber volume fraction may cause undesirable resin flow pattern and thus result in dry spots, which affect the mechanical properties of the finished parts. In this study, a real time RTM control strategy to reduce these unfavorable effects is proposed. Through numerical simulations and experiments, the validity of the proposed scheme is demonstrated.

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Diversity and Characteristics of the Meat Microbiological Community on Dry Aged Beef

  • Ryu, Sangdon;Park, Mi Ri;Maburutse, Brighton E.;Lee, Woong Ji;Park, Dong-Jun;Cho, Soohyun;Hwang, Inho;Oh, Sangnam;Kim, Younghoon
    • Journal of Microbiology and Biotechnology
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    • v.28 no.1
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    • pp.105-108
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    • 2018
  • Beef was dry aged for 40-60 days under controlled environmental conditions in a refrigerated room with a relative humidity of 75%-80% and air-flow. To date, there is little information on the microbial diversity and characteristics of dry aged beef. In this study, we explored the effect of change in meat microorganisms on dry aged beef. Initially, the total bacteria and LAB were significantly increased for 50 days during all dry aging periods. There was an absence of representative foodborne pathogens as well as coliforms. Interestingly, fungi including yeast and mold that possess specific features were observed during the dry aging period. The 5.8S rRNA sequencing results showed that potentially harmful yeasts/molds (Candida sp., Cladosporium sp., Rhodotorula sp.) were present at the initial point of dry aging and they disappeared with increasing dry aging time. Interestingly, Penicillium camemberti and Debaryomyces hansenii used for cheese manufacturing were observed with an increase in the dry aging period. Taken together, our results showed that the change in microorganisms exerts an influence on the quality and safety of dry aged beef, and our study identified that fungi may play an important role in the palatability and flavor development of dry aged beef.

The Gettering Effect of Boron Doped n-type Monocrystalline Silicon Wafer by In-situ Wet and Dry Oxidation

  • Jo, Yeong-Jun;Yun, Ji-Su;Jang, Hyo-Sik
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.429-429
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    • 2012
  • To investigate the gettering effect of B-doped n-type monocrystalline silicon wafer, we made the p-n junction by diffusing boron into n-type monocrystalline Si substrate and then oxidized the boron doped n-type monocrystalline silicon wafer by in-situ wet and dry oxidation. After oxidation, the minority carrier lifetime was measured by using microwave photoconductance and the sheet resistance by 4-point probe, respectively. The junction depth was analyzed by Secondary Ion Mass Spectrometry (SIMS). Boron diffusion reduced the metal impurities in the bulk of silicon wafer and increased the minority carrier lifetime. In the case of wet oxidation, the sheet resistance value of ${\sim}46{\Omega}/{\Box}$ was obtained at $900^{\circ}C$, depostion time 50 min, and drive-in time 10 min. Uniformity was ~7% at $925^{\circ}C$, deposition time 30 min, and drive-in time 10 min. Finally, the minority carrier lifetime was shown to be increased from $3.3{\mu}s$ for bare wafer to $21.6{\mu}s$ for $900^{\circ}C$, deposition 40 min, and drive-in 10 min condition. In the case of dry oxidation, for the condition of 50 min deposition, 10 min drive-in, and O2 flow of 2000 SCCM, the minority carrier lifetime of 16.3us, the sheet resistance of ${\sim}48{\Omega}/{\Box}$, and uniformity of 2% were measured.

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Initial Stage of Atmospheric Corrosion of Carbon and Weathering Steels in Thailand Climate

  • Nii, K.;Bhamornsut, C.;Chotimongkol, L.;Vutivat, E.;Nakkhuntod, R.;Jeenkhajohn, P.;Suphonlai, S.
    • Corrosion Science and Technology
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    • v.2 no.4
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    • pp.183-188
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    • 2003
  • Corrosion of carbon and weathering steels were evaluated under 3 environmental exposures in Thailand (urban, rural and marine) for a year. The seasonal study was designed to determine different corrosion mechanisms by 6 months of dry season and 6 months of rainy season in a year. The sheltered exposure racks were used to determine the washing effect of min. At each site, climatic and pollutants analyses were carried out. The present study showed that the difference in corrosion rates of carbon and weathering steels was not so distinguished in both rural (AIT) and urban (TISTR) environments. The corrosion rate of weathering steel was somewhat lower than that of carbon steel and the decreasing tendency of corrosion rate with time was slightly higher for weathering steel than for carbon steel. In marine (Rayong) environment, the corrosion rate was higher and the effect of wet and dry seasons was observed. The corrosion rate in 6 dry months was higher for direct exposure than for sheltered exposure. However, in 6 rainy months. the corrosion rate of sheltered exposure was higher than that of direct exposure. In direct exposure for I year, that is, the first 6 dry months and the next 6 rainy months, the corrosion rate decreased with time. but in sheltered exposure, the corrosion rate did not decrease with time. instead, increased in the next 6 rainy months. This indicated that the protect ive layer formed in the first 6 dry months could be destroyed by high deposition of chloride to r sheltered exposure in the next 6 rainy months; whereas the rust layer for direct exposure could be kept sound due to washing effect in rainy season, even though the deposition rate of chloride was almost the same for direct and sheltered exposures. In marine environment, the weathering steel showed higher corrosion resistance than carbon steel but its corrosion rate was higher than those in other environments.

Numerical modeling of seawater flow through the flooding system of dry ocks

  • Najafi-Jilani, A.;Naghavi, A.
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.1 no.2
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    • pp.57-63
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    • 2009
  • Numerical simulations have been carried out on the flooding system of a dry located at the south coasts of Iran. The main goals of seawater flow haracteristics in the intake channels conditions of the flooding system are imposed in the modeling. The upstream boundary condition is the tidal fluctuations of sea water level. At the downstream, the gradually rising water surface elevation in the dry described in a transient boundary condition. The numerical results are compared with available laboratory a good agreement is obtained. The seawater discharge through the flooding system and the required time to filling up the dry dock is determined at the worst case. The water current velocity and pressure on the rigid boundaries are discussed.

EFFECT OF WETTING CONDITION ON BONDING OF RESIN CEMENT TO DENTIN (상아질 표면의 건조에 따른 습윤상태가 레진세멘트의 접착에 미치는 영향)

  • Son, Kang-Ha;Park, Jin-Hoon;Cho, Kyeu-Zeung
    • Restorative Dentistry and Endodontics
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    • v.20 no.1
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    • pp.97-112
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    • 1995
  • The purpose of this study was to evaluate the effect of wetting condition made by drying time on bonding of resin cement to dentin. Freshly extracted bovine teeth were grinded to expose flat dentin surfaces. After the exposed dentin surfaces were treated with pretreatment agents and water rinse, each wetting condition of dentin surfaces was made according to drying times and methods including slight blow bry for I-second by air syringe, blow dry for 20-second by air syringe, and 12-hour dry in desiccator respectively. and then, previously made composite resin specimens were bonded onto each conditioned dentin surface of the specimen using Panavia-21(Kuraray Co.), Bistite(Tokuso Co.), and Choice(use with All bond-2, Bisco Inc.) resin cement according as manufacturer's instruction. Bonded specimens were stored in $37^{\circ}C$ distilled water for 24 hours, then the tensile bond strength was measured, cohesive failure rate was calculated, and fractured dentin surfaces and acrylic rod sides were examined under scanning electron microscope. The result were as follows ; In the group of bonding with Panavia-21 resin cement, higher tensile bond strength was seen in 12-hour dry group than in I-second and 20-second dry group(p<0.01). In the group of bonding with Bistite resin cement, higher tensile bond strength was seen in 1-second dry group than in 20-second and 12-hour dry group(p<0.01). In the group of bonding with Choice resin cement, no significant differences of bond strength under given drying time were seen. Cohesive failure rates derived from the groups of bonding with Panavia-21 and Choice resin cement were increased with the increase of tensile bond strength in each drying time. On SEM examination of fractured surface, adhesive failure mode with fractured resin tags was mostly seen in wet condition with I-second drying time in the group of bonding with Panavia-21 resin cement, mixed failure mode with shortened and fractured resin tag was seen in the group of bonding with Bistite resin cement, and regardless of drying time, and cohesive-adhesive mixed failure mode with fracture of 'Hollow' typed resin tags was mainly seen in the group of bonding with Choice resin cement.

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Some Schemes for the sustainable Development of Korean Laver Industry (우리나라 김 산업 발전을 위한 논점과 방안)

  • Ock, Young-Soo
    • The Journal of Fisheries Business Administration
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    • v.41 no.2
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    • pp.25-44
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    • 2010
  • The laver has been cultivated long time ago in Korea. And traditional production system was changed to new system about 30 years ago. The new production system is understood the specialization of laver products, that is, originally individual fishery households made final laver products from raw cultured laver in sea working to dry working in land, but the new system was separated raw laver production in sea and dry laver production, which made final dry laver products by purchase the raw laver in land. This change has been increased laver production, 10 billion sheets in 2000's from 5 billion sheets in 1980's. And rapid production increase gave rise to some troubles on laver industry that is a serious drop in real laver prices, discord structure between raw laver producer and dry laver producer, stagnation of laver consumption, etc. Now Korea is the best laver production country together with Japan in world. Then we have to consider some schemes for the sustainable development of laver industry. One of such schemes is export enlargement of laver against world. The consumption of laver has been globally increased in recent. The other is the grading test problem of dry laver. Because the rapid increase of laver production caused to drop laver quality. Then we seriously have to consider the grading test of dry laver for high level quality production.

The Effects of Dry Cupping Therapy on the Shoulder Pain and Fatigue of Nurses (건부항요법이 간호사의 견통과 피로도에 미치는 영향)

  • Sohn, Dorina;Yoon, Hyun-Min;Jung, Hyang-Mi
    • Journal of Pharmacopuncture
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    • v.14 no.2
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    • pp.25-35
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    • 2011
  • Objective : This research was done to identify the effects of dry cupping therapy on the shoulder pain and fatigue of nurses. Methods : The research design was time series design. The participants were 27 nurses with shoulder pain at P University Hospital in Busan metropolitan city from July 6, 2009 to August 3, 2009. The dry cupping therapy was done 4 times, twice a week for 2 weeks. Before intervention, the severity and frequency of pain and fatigue were measured three times at one week intervals, and then those were measured after one week and two weeks of experimental treatment. The results were analyzed using descriptive statistics, paired t-test and repeated measure ANOVA with the SPSS program. Results : There were statistically significant difference in severity and frequency of shoulder pain, and fatigue after dry cupping therapy. Dry cupping therapy was effective for the management of shoulder pain and fatigue among nurses in this study. Conclusion : Therefore dry cupping therapy can be considered an effective nursing intervention that relieves shoulder pain and fatigue of nurses.

Analysis of Characteristics of Spent Fuels on Long-Term Dry Storage Condition

  • Yoon, Suji;Park, Kwangheon;Yun, Hyungju
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.19 no.2
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    • pp.205-214
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    • 2021
  • Currently, the interim storage pools of spent fuels in South Korea are expected to become saturated from 2024. It is required to prepare an operation plan of a domestic dry storage facility during a long-term period, with the researches on safety evaluation methods. This study modified the FRAPCON code to predict the spent fuel integrity evaluation such as the axial cladding temperature, the hoop stress and hydrogen distribution in dry storage. The cladding temperature in dry storage was calculated using the COBRA-SFS code with the burnup information which was calculated using the FRAPCON code. The hoop stress was calculated using the ideal gas equation with spent fuel information such as rod internal pressure. Numerical analysis method was used to calculate the degree of hydrogen diffusion according to the hydrogen concentration and temperature distribution during a dry storage period. Before 50 years of dry storage, the cladding temperature and hoop stress decreased rapidly. However, after 50 years, they decreased gradually and the cladding temperature was below 400 K. The initial temperature distribution and hydrogen concentration showed a parabolic line, but hydrogen was transferred by the hydrogen concentration and temperature gradient over time.

Study on Adaptation, Dry Matter Yield and Nutrient Value of Kenaf(Hibiscus cannabinus L.) on Jeju Province (양마의 제주지역 지역 적응성, 생산성 및 사료가치에 관한 연구)

  • Hwang, Kyung-Jun;Kim, Moon-Cjul;Kang, Si-Young;Yu, Jang-Geal;Song, Sang-Teak;Park, Nam-Geon;Kim, Jong-Ha
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.22 no.4
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    • pp.287-296
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    • 2002
  • A field trial was conducted from May to November 2000 at four regions of Jeju province(Jeju, Seogwipo, Susan Seongsan and Keumak Hallim) to estimate adaptation, dry matter yield and nutrient value of kenafs(Everglades 41 and China Choung-pi 3) and a sorghum-sudangrass hybrid(Pioneer 947). Total dry matter(DM) yields of sorghum-sudangrass hybrid Pioneer 947, kenaf Everglades 41 and kenaf China Chong-pi 3 were 7,313, 4,653 and 5,238 kg/ha(P<0.05), respectively, kenaf China Chong-pi 3 being the highest. The region specific dry matter(DM) yields of Jeju, Seogwipo, Seongsan and Hallim area were 5,040, 5,663, 7,283 and 4,950kg/ha, respectively, showing that Seogwipo was the highest. Average DM yields of two kenaf varieties were 4,946, and 3,246 kg/ha for 1st time-cutting and 2nd time-cutting, respectively. The average dry matter(DM) yield of kenaf was significantly higher in the 1st time-cutting than the 2nd time. No significant difference in neutral detergent fiber(NDF) and acid detergent fiber(ADF) contents was found among three varieties. The average crude protein(CP) content of kenaf was higher than that of sorghum-sudangrass hybrid(P<0.05) and was higher in 2nd time-cutting than in 1st time-cutting(P<0.05). There were no significant difference in the heavy metal content of soil either between the sorghum hybrid and kenafs or between two kenaf varieties. In conclusion, the average dry matter(DM) yield of kenaf was lower than that of sorghum hybrid, Contrarily the crude protein(CP) content of kenafs was higher than that of the sorghum hybrid. The average dry matter(DM) yield of kenaf showed higher in 1st time-cutting than 2nd time-cutting, while the crude protein(CP) content of kenafs decreased with time.