• Title/Summary/Keyword: Energy per unit area

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Studies on the Improvement of Mountainous Pasture III. Effect of seed coating on oversown pasture (산지초지 개량에 관한 연구 III. 종자 Coating에 의한 겉뿌림 초지육성)

  • 이인덕
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.4 no.3
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    • pp.194-200
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    • 1984
  • Effects of seed coating on establishment, early growth and herbage production were investigated in Pot, Soil box and Field experiments. Seed was coated with 60% Lime, 20% Phosphate and 20% Peatmoss(W/W), also finely sprayed 13% Arabic gum and 2% Methyl cellulose(W/V). Coating were generally 1:20, seed: coat(W/W). 1. In the general growth of the growing stages and different oversown species at 80 days, seed coated was promoted than none in early growth. (Table 2 and 3) 2. Stand counts at 60 days after oversown, seed coated was higher 15% than none, especially, there was advantage due to coating on the medium and large size seeds such as Orchardgrass, Perennial ryegrass and Kentucky bluegrass, but did not assist establishment of the large (Tall fescue) and small (Ladino clover) size seed. 3. Variation of sward composition was not quite different between two treatments, but seed coated was slightly increased the Percentage of sown grasses with advance of cutting time. 4. Total dry metter yield per unit area with seed coated was higher 17% than none in establishment year. 5. Variations in the chemical composition of the herbage and soil were influenced by coating materials in the coating regime (Table 8). 6. From these facts, seed coated also appeared that adequate seedling stands, early growth and herbage production could be obtained with higher than conventional overseeding method under a poor conditions.

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A review on the design requirement of temperature in high-level nuclear waste disposal system: based on bentonite buffer (고준위폐기물처분시스템 설계 제한온도 설정에 관한 기술현황 분석: 벤토나이트 완충재를 중심으로)

  • Kim, Jin-Seop;Cho, Won-Jin;Park, Seunghun;Kim, Geon-Young;Baik, Min-Hoon
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.5
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    • pp.587-609
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    • 2019
  • Short-and long-term stabilities of bentonite, favored material as buffer in geological repositories for high-level waste were reviewed in this paper in addition to alternative design concepts of buffer to mitigate the thermal load from decay heat of SF (Spent Fuel) and further increase the disposal efficiency. It is generally reported that the irreversible changes in structure, hydraulic behavior, and swelling capacity are produced due to temperature increase and vapor flow between $150{\sim}250^{\circ}C$. Provided that the maximum temperature of bentonite is less than $150^{\circ}C$, however, the effects of temperature on the material, structural, and mineralogical stability seems to be minor. The maximum temperature in disposal system will constrain and determine the amount of waste to be disposed per unit area and be regarded as an important design parameter influencing the availability of disposal site. Thus, it is necessary to identify the effects of high temperature on the performance of buffer and allow for the thermal constraint greater than $100^{\circ}C$. In addition, the development of high-performance EBS (Engineered Barrier System) such as composite bentonite buffer mixed with graphite or silica and multi-layered buffer (i.e., highly thermal-conductive layer or insulating layer) should be taken into account to enhance the disposal efficiency in parallel with the development of multilayer repository. This will contribute to increase of reliability and securing the acceptance of the people with regard to a high-level waste disposal.

Statistical Characteristics of East Sea Mesoscale Eddies Detected, Tracked, and Grouped Using Satellite Altimeter Data from 1993 to 2017 (인공위성 고도계 자료(1993-2017년)를 이용하여 탐지‧추적‧분류한 동해 중규모 소용돌이의 통계적 특성)

  • LEE, KYUNGJAE;NAM, SUNGHYUN;KIM, YOUNG-GYU
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.24 no.2
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    • pp.267-281
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    • 2019
  • Energetic mesoscale eddies in the East Sea (ES) associated with strong mesoscale variability impacting circulation and environments were statistically characterized by analyzing satellite altimeter data collected during 1993-2017 and in-situ data obtained from four cruises conducted between 2015 and 2017. A total of 1,008 mesoscale eddies were detected, tracked, and identified and then classified into 27 groups characterized by mean lifetime (L, day), amplitude (H, m), radius (R, km), intensity per unit area (EI, $cm^2/s^2/km^2$), ellipticity (e), eddy kinetic energy (EKE, TJ), available potential energy (APE, TJ), and direction of movement. The center, boundary, and amplitude of mesoscale eddies identified from satellite altimeter data were compared to those from the in-situ observational data for the four cases, yielding uncertainties in the center position of 2-10 km, boundary position of 10-20 km, and amplitude of 0.6-5.9 cm. The mean L, H, R, EI, e, EKE, and APE of the ES mesoscale eddies during the total period are $95{\pm}104$ days, $3.5{\pm}1.5cm$, $39{\pm}6km$, $0.023{\pm}0.017cm^2/s^2/km^2$, $0.72{\pm}0.07$, $23{\pm}21TJ$, and $588{\pm}250TJ$, respectively. The ES mesoscale eddies tend to move following the mean surface current rather than propagating westward. The southern groups (south of the subpolar front) have a longer L, larger H, R, and higher EKE, APE; and stronger EI than those of the northern groups and tend to move a longer distance following surface currents. There are exceptions to the average characteristics, such as the quasi-stationary groups (the Wonsan Warm, Wonsan Cold, Western Japan Basin Warm, and Northern Subpolar Frontal Cold Eddy groups) and short-lived groups with a relatively larger H, higher EKE, and APE and stronger EI (the Yamato Coastal Warm, Central Yamato Warm, and Eastern Japan Basin Coastal Warm eddy groups). Small eddies in the northern ES hardly resolved using the satellite altimetry data only, were not identified here and discussed with potential over-estimations of the mean L, H, R, EI, EKE, and APE. This study suggests that the ES mesoscale eddies 1) include newly identified groups such as the Hokkaido and the Yamato Rise Warm Eddies in addition to relatively well-known groups (e.g., the Ulleung Warm and the Dok Cold Eddies); 2) have a shorter L; smaller H, R, and lower EKE; and stronger EI and higher APE than those of the global ocean, and move following surface currents rather than propagating westward; and 3) show large spatial inhomogeneity among groups.