• Title/Summary/Keyword: Dry spot

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Phenomenological behavior of Bubbles and dry spots at CHF on a short heated wall: Pool boiling of R-113 (소형가열면에서 CHF 발생시 Bubble 및 Dry Spot의 현상학적 거동 R-113의 수조비등)

  • Chung, H.J.;Kim, B.D.;Chun, S.Y.;No, H.C.
    • Proceedings of the KSME Conference
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    • 2001.06d
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    • pp.189-194
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    • 2001
  • A simultaneous visualization of the behavior of bubbles and dry spots has been carried out for pool boiling of R-1l3 on a horizontal heater. From video imaging and image processing analysis, the formation of bubbles and dry spots occurs simultaneously, and therefore they should be considered as a synchronized concept rather than independent identities. The dry spot density is equivalent to the active site density in the region before CHF. At CHF point, large dry areas due to the coalescence of neighboring dry areas cover the heater surface.

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Influence of Level of Feed Intake on Concentration of Purine Derivatives in Urinary Spot Samples and Microbial Nitrogen Supply in Crossbred Bulls

  • George, S.K.;Dipu, M.T.;Mehra, U.R.;Verma, A.K.;Singh, P.
    • Asian-Australasian Journal of Animal Sciences
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    • v.19 no.9
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    • pp.1291-1297
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    • 2006
  • The potential of the spot urine sampling technique as an alternative to performing a total urine collection to predict the microbial nitrogen supply was evaluated in crossbred bulls. In a completely randomized design, 20 growing crossbred bulls were assigned four levels of feed intake (120, 100, 80 and 60% of voluntary dry matter intake) on diets comprised of wheat straw and concentrate mixture (50:50). After three months of experimental feeding, a metabolism trial was conducted for ten days, during which spot urine collections were performed every 6 h post feeding on days 9 and 10. The daily urinary excretion of allantoin (A) and purine derivatives (PD) decreased with the reduction in feed intake while creatinine (C) excretion remained similar in animals fed at different levels. The microbial nitrogen (MN) supply calculated from the PD excreted in total urine (35.08 to 72.08 g/d) was higher at increased levels of feed intake. PD concentration in spot urine samples had poor correlation with feed intake except at 12 h post feeding. A/C ratio and PD/C ratio in spot urine samples remained similar irrespective of sampling time and significantly (p<0.01) correlated with daily urinary PD excretion, digestible organic matter intake and dry matter (DM) intake. However, no significant differences were evident in these ratios among animals fed at levels 120, 100 and 80% of voluntary dry matter intake (VDMI) at different times post feeding. These results suggests that the spot urine sampling technique to predict the microbial protein supply is not suitable for detecting small differences in MN supply and hence, estimation of PD excreted in total urine (mmol/d) is necessary to assess precisely the MN supply in crossbred bulls.

Integration of GIS-based RUSLE model and SPOT 5 Image to analyze the main source region of soil erosion

  • LEE Geun-Sang;PARK Jin-Hyeog;HWANG Eui-Ho;CHAE Hyo-Sok
    • Proceedings of the KSRS Conference
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    • 2005.10a
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    • pp.357-360
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    • 2005
  • Soil loss is widely recognized as a threat to farm livelihoods and ecosystem integrity worldwide. Soil loss prediction models can help address long-range land management planning under natural and agricultural conditions. Even though it is hard to find a model that considers all forms of erosion, some models were developed specifically to aid conservation planners in identifying areas where introducing soil conservation measures will have the most impact on reducing soil loss. Revised Universal Soil Loss Equation (RUSLE) computes the average annual erosion expected on hillslopes by multiplying several factors together: rainfall erosivity (R), soil erodibility (K), slope length and steepness (LS), cover management (C), and support practice (P). The value of these factors is determined from field and laboratory experiments. This study calculated soil erosion using GIS-based RUSLE model in Imha basin and examined soil erosion source area using SPOT 5 high-resolution satellite image and land cover map. As a result of analysis, dry field showed high-density soil erosion area and we could easily investigate source area using satellite image. Also we could examine the suitability of soil erosion area applying field survey method in common areas (dry field & orchard area) that are difficult to confirm soil erosion source area using satellite image.

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A Dry-Spot Model for the Prediction of Critical Heat Flux in Water Boiling in Bubbly Flow Regime

  • Ha, Sang-Jun;No, Hee-Cheon
    • Proceedings of the Korean Nuclear Society Conference
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    • 1997.10a
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    • pp.546-551
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    • 1997
  • This paper presents a prediction of critical heat flux (CHF) in bubbly flow regime using dry-spot model proposed recently by authors for pool and flow boiling CHF and existing correlations for forced convective heat transfer coefficient, active site density and bubble departure diameter in nucleate boiling region. Without any empirical constants always present in earlier models, comparisons of the model predictions with experimental data for upward flow of water in vertical, uniformly-heated round tubes are performed and show a good agreement. The parametric trends of CHF have been explored with respect to variations in pressure, tube diameter and length, mass flux and inlet subcooling.

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

  • Jeon Young Jae;Um Moon Kwang;Byun Joon Hyung;Lee Woo Il
    • Composites Research
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    • v.18 no.4
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    • pp.35-43
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    • 2005
  • In resin transfer molding(RTM), race-track effects and non-uniform fiber volume fraction may cause undesirable resin flow patterns 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. This control rule is accomplished by means of the permeability mapping and pressure regulation. Through numerical simulations, the validity of the proposed scheme is demonstrated.

Application of SPOT 5 Satellite Image and Landcover Map for the examination of Soil Erosion Source Area (토사유실 원인지역 검토를 위한 SPOT 5 위성영상과 토지피복도의 활용)

  • Lee, Geun-Sang;Park, Jin-Hyeog;Hwang, Eui-Ho;Koh, Deuk-Koo
    • Journal of Korea Water Resources Association
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    • v.38 no.11
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    • pp.927-935
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    • 2005
  • Soil erosion by rainfall is important factor for basin management because it reduces reservoir capacity and breaks out the contamination of water caused by turbid water. Recently, soil erosion study with GIS is in progress but does not consider soil erosion source area. This study calculated soil erosion amount using GIS-based soil erosion model in Imha basin and examined soil erosion source area using SPOT 5 High-resolution satellite image and land cover map. As a result of analysis, dry field showed high-density soil erosion area and we could easily investigate source area using satellite image. Also we could examine the suitability of soil erosion area by applying field survey method in common areas such as dry field and orchard area those are difficult to confirm soil erosion source area using satellite image.

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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Analysis of Land Cover Classification and Pattern Using Remote Sensing and Spatial Statistical Method - Focusing on the DMZ Region in Gangwon-Do - (원격탐사와 공간통계 기법을 이용한 토지피복 분류 및 패턴 분석 - 강원도 DMZ일원을 대상으로 -)

  • NA, Hyun-Sup;PARK, Jeong-Mook;LEE, Jung-Soo
    • Journal of the Korean Association of Geographic Information Studies
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    • v.18 no.4
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    • pp.100-118
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    • 2015
  • This study established a land-cover classification method on objects using satellite images, and figured out distributional patterns of land cover according to categories through spatial statistics techniques. Object-based classification generated each land cover classification map by spectral information, texture information, and the combination of the two. Through assessment of accuracy, we selected optimum land cover classification map. Also, to figure out spatial distribution pattern of land cover according to categories, we analyzed hot spots and quantified them. Optimal weight for an object-based classification has been selected as the Scale 52, Shape 0.4, Color 0.6, Compactness 0.5, Smoothness 0.5. In case of using the combination of spectral information and texture information, the land cover classification map showed the best overall classification accuracy. Particularly in case of dry fields, protected cultivation, and bare lands, the accuracy has increased about 12 percent more than when we used only spectral information. Forest, paddy fields, transportation facilities, grasslands, dry fields, bare lands, buildings, water and protected cultivation in order of the higher area ratio of DMZ according to categories. Particularly, dry field sand transportation facilities in Yanggu occurred mainly in north areas of the civilian control line. dry fields in Cheorwon, forest and transportation facilities in Inje fulfilled actively in south areas of the civilian control line. In case of distributional patterns according to categories, hot spot of paddy fields, dry fields and protected cultivation, which is related to agriculture, was distributed intensively in plains of Yanggu and in basin areas of Cheorwon. Hot spot areas of bare lands, waters, buildings and roads have similar distribution patterns with hot spot areas related to agriculture, while hot spot areas of bare lands, water, buildings and roads have different distributional patterns with hot spot areas of forest and grasslands.

Effects of Calcium Fertilization on the Occurrence of the Internal Brown Spot in Solanum tuberosum cv. Atlantic (칼슘施肥가 감자品種 '大西'의 內部褐色班點 發生에 미치는 影響)

  • 김현준
    • Korean Journal of Plant Resources
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    • v.10 no.1
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    • pp.11-16
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    • 1997
  • Effects of calcium on the total tuber yield, dry matter content, internal brown spot and hollow heart of a processing potato cv. Atlantic were investigated to obtain some basic informations in summer cropping. The occurrence rate of the internal brown spots in cv. Atlantic tubers were highly decreased with the significant differences in the Ca-treated plots compared to the Ca-nontreated plots. However, no significant differences amongs Ca-treated plots were shown. Plant height and the number of main stems were not affected by the changes of the calcium levels, but top fresh weight was the highest in the plots of Ca(200kg/ha) level. In addition to its total yield, dry matter content, hollow heart was not affected by calcium fertilization. Therefore, the causal factor of the internal brown spot is attributed to the calcium deficiency in the tubers of cv. Atlantic.

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A Simple Device of the Dry Tetrabromophenolphthalein Ethyl Ester Reagent Strip for the Detection of Methamphetamine

  • Choi, Myung-Ja;Song, Eun-Young;Kim, Seung-Ki;Choi, Jeong-Eun;Lho, Dong-Seok;Park, Jong-Sei
    • Archives of Pharmacal Research
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    • v.16 no.3
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    • pp.227-230
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    • 1993
  • A new device to detect methamphetamine (MA), amphetamine(A) and its metabolites in urine was developed using the paper strip method and the test tube method of dry chemical reagents. The reagent containing tetrabromophenolphthalein ethyl ester (TBPE) and borax. For the TBPE paper strip method, a device was prepared with a window at each end of the reagent paper strip ; one window is for the sample application, and the other window is for the methylene chloride. The diffused sample from one window reacts with reagent in the paper and produces color at the point where it meets with methylene chloride which has diffused form the other side. A positive smaple produces as red-purple color and the negative sample a greenish color, with a detection limit of 5-10 ppm. The result can be obtained within one minute. For the TBPE test tube method which contains dry reagents, the detection limit is 5 ppm and the result can be obtaineed within 30 seconds, however the carry-on is not as convenient as the paper strip method. The performance of both methods were evlauated by comparing with the results of gas chromatography (GC) and fluorescence polarizaiton immunoassay (FPIA). The results were proven that both methods were useful as primary screening reagents to detect MA in urine and in dry powder.

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