• Title/Summary/Keyword: wet release

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Artificial seed production and cultivation of Sargassum macrocarpum (Fucales, Phaeophyta)

  • Ko, Shin Ja;Kim, Yoo Kyung;Hong, Seong Wan;Kang, Min Su;Park, Chan Sun;Hwang, Eun Kyoung;Lee, Young Don
    • ALGAE
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    • v.35 no.2
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    • pp.123-131
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    • 2020
  • Sargassum macrocarpum is a rich source of anti-inflammatory compounds. Recently, one of the compounds, tuberatolide B, has been reported as a functional anti-inflammatory additive for foods and nutraceuticals. The artificial seeding, growth and maturation of S. macrocarpum were investigated from May 2018 to September 2019. Indoor culture experiments for induction of egg release were conducted at temperatures of 17, 20, 23, and 26℃ and irradiances of 0, 10, 20, 40, and 80 μmol photons m-2 s-1 under 14 : 10 h (L : D) photoperiod. Within a given treatment combination, higher temperatures and irradiance levels favoured the maturation of receptacles in S. macrocarpum. Using artificial temperature and irradiance control, thalli matured one month earlier than thalli in nature. Under natural condition, receptacle formation began in April, and the eggs were released in June and July. The release of eggs from the receptacles was promoted at 17-20℃ and 40-80 μmol photons m-2 s-1, and the fastest growth of germlings occuring at 15-17℃ and 40 μmol photons m-2 s-1. For mature thalli, 300 g wet-weight was sufficient to seed 100 m of seed string. Thalli grew to 10.5 ± 2.6 cm in length at a density of 6.7 ± 3.3 individuals m-1 after 1 year of cultivation, from germination. This study demonstrates that it is possible to cultivate S. macrocarpum for the production of anti-inflammatory products.

Analytical Model of Salt Budget in the Upper Indian River Lagoon, Florida USA

  • Kim, Young-Taeg
    • Ocean and Polar Research
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    • v.26 no.1
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    • pp.33-42
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    • 2004
  • Effect of freshwater discharge on the long-term salt balance in the Northern and Central Indian River Lagoon (IRL) is successfully simulated by a new analytical solution to a water balance-based one-dimensional salt conservation equation. Sensitivity tests show that the salinity levels drop abruptly even during the dry season (November to May) due to the high surface runoff discharge caused by tropical storms, depressions, and passage of cold fronts. Increasing surface runoff and direct precipitation has risen by ten times, lowering the salinity level down to 12psu in the Northern Central zone, and to 17 psu in the Northern zone. However, the salinity level in the Southern Central zone has decreased to 25 psu. High sensitivity of the Northern Central zone to freshwater discharge can be partially explained by a rapid urbanization in this zone. During the dry season, less sensitivity of the Southern Central zone to the increased surface runoff is attributed to the proximity of the zone to the Sebastian Inlet and a strong diffusion condition possibly resulting from the seawater intrusion to the surficial aquifer at the Vero Beach. During the wet season, however, the whole study area is highly sensitive to freshwater discharge due to the weak diffusion conditions. High sensitivity of the IRL to the given diffusion conditions guarantees that the fresh-water release occurs during strong wind conditions, achieving both flood control in the drainage basin and a proper salinity regime in the IRL.

An Experimental Study on the Bed Combustion Phenomena in MSW(Municipal Solid Waste) Incinerator (폐기물 소각로 베드에서의 연소현상 관찰을 위한 실험적 연구)

  • Min, Jee Hyun;Shin, Donghoon;Choi, Sangmin
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.23 no.2
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    • pp.159-165
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    • 1999
  • Experimental studies have been performed to observe the basic phenomena of waste bed combustion in MSW incinerator. A reduced scale apparatus was utilized to simulate the combustion behavior in real plant with 1-dimensional transient behavior at the experimental setup, which uses wet cubic wood with ash content as simulated waste. LHV (lower heating value) of solid fuel, fuel particle size and flow rate of combustion air were taken as important parameters of the bed combustion. For the quantitative analysis, FPR (flame propagation rate), TBT (total burn-out time) and PBT (particle burn-out time) was defined. LHV represent the capability of heat release of the fuel, so that a higher LHV results in faster reaction rate of the fuel bed, which is shown by higher FPR. Fuel particle size is related with surface area per unit mass as well as heat and mass transfer coefficient. As the particle size increases the FPR decreases owing to decreasing specific surface area. Air injection supplies oxygen to the reaction zone. However oversupply of combustion air increases convection cooling of the bed and possibly extinguishes the flame.

Effect of Polysorbate 80 on the Dissolution of Sulfanilamide and Sulfacetamide Granules (Polysorbate 80이 Sulfanilamide및 Sulfacetamide 과립의 용출에 미치는 영향)

  • 구영순;이정순
    • YAKHAK HOEJI
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    • v.31 no.3
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    • pp.189-196
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    • 1987
  • This study was carried out to investigate the effect of surfactant on the dissolution of relatively hydrophilic drugs, such as sulfanilamide (SF) and sulfacetamide (SFA) granules prepared by wet granulation. The additive incorporated in the granules is starch or microcrystalline cellulose(MCC) as an excipient, PVP as a binder, and polysorbate 80 (P-80) as a surfactant. The dissolution characteristics of SF and SFA granules in distilled water were as follows: The values of T$_{75%}$ were 4.60 and 2.50min, respectively for SF and SFA granules. Incorporation of 0.1% P-80 in SF granule ratarded the dissolution of SF as compared with control, but addition of 0.1% P-80 to SFA granule improved the dissolution of SFA in comparison with control. In SF and SFA granules formulated with either starch or PVP, the release of the drug was increased as compared with control. In SF granule, the dissolution of the drug was further reduced by the inclusion of P-80 in the granule containing starch or PVP. Incorporation of P-80 in SFA granule with starch or PVP affected little on the dissolution of the drug. Addition of a nonswelling excipient, MCC decreased the dissolution rate of SF and SFA granules. as compared with each control. The presence of P-80 in these granules made the dissolution rate slower in comparison with the granules containing only MCC.

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Current Issues, Trends and Possibilities in Water Sector in Nepal

  • Shrestha, Hari Krishna
    • Water for future
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    • v.52 no.8
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    • pp.56-66
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    • 2019
  • Nepal is bestowed with abundant water. With more than 1500 mm average annual rainfall in the country, a vast quantity of underutilized groundwater in the Terai belt, and the water stored in snowcaps in the Himalayas, aquifers in the mountains and glacial lakes, Nepal is potentially in an advantageous position in terms of per capita availability. However, low emphasis in management aspect of water and high emphasis in infrastructural developments related to water resources management has resulted in conversion of water in Nepal from a resource to a burden. The global climate change, reduction in number of rainy days, increase in intensity of rainfall during wet monsoon season, encroachment of river banks for settlement, inadequate release of environmental flows from hydropower plants, and attempt to tame the mighty and high velocity rivers of Nepal have resulted in increasing number of water induced disasters (flood and landslide), rise in conflict between local residents and hydropower developers, higher number of devastating landslides, and in some extreme cases mass migration of residents resulting in climate refugees. There is a ray of hope; the awareness level of the people regarding sustainable use of water resources is increasing, the benefit sharing mechanism is gradually being implemented, the role of interdisciplinary and integrated water resources management is appreciated at a higher level and the level of preparedness against flood and landslides is at a higher degree compared to a couple of decades ago. With the use of renewable energy sources, the possibilities for sustainable and productive use of water are on the rise in Nepal.

Grain Size Analysis by Hot-Cooling Cycle Thermal Stress at Y-TZP Ceramics using Full Width at Half Maximum(FWHM) of X-ray Diffraction (X-ray 회절의 반치전폭(FWHM)을 이용한 Y-TZP세라믹스에서 반복 열응력에 의한 입계크기 분석)

  • Choi, Jinsam;Park, Kyu Yeol;Kong, Young-Min
    • Korean Journal of Materials Research
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    • v.29 no.4
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    • pp.264-270
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    • 2019
  • As a case study on aspect ratio behavior, Kaolin, zeolite, $TiO_2$, pozzolan and diatomaceous earth minerals are investigated using wet milling with 0.3 pai media. The grinding process using small media of 0.3 pai is suitable for current work processing applications. Primary particles with average particle size distribution D50, ${\sim}6{\mu}m$ are shifted to submicron size, D50 ${\sim}0.6{\mu}m$, after grinding. Grinding of particles is characterized by various size parameters such as sphericity as geometric shape, equivalent diameter, and average particle size distribution. Herein, we systematically provide an overview of factors affecting the primary particle size reduction. Energy consumption for grinding is determined using classical grinding laws, including Rittinger's and Kick's laws. Submicron size is obtained at maximum frictional shear stress. Alterations in properties of wettability, heat resistance, thermal conductivity, and adhesion increase with increasing particle surface area. In the comparison of the aspect ratio of the submicron powder, the air heat conductivity and the total heat release amount increase 68 % and 2 times, respectively.

Improvement of a Dynamic Food Chain Model Considering the Influence of Radioactive Contamination of Foods by Rainfall During a Nuclear Emergency (원자력 사고 중 강우에 의한 음식물 오염영향을 고려한 역동학적 섭식경로모델 개선)

  • Hwang, Won-Tae;Kim, Eun-Han;Han, Moon-Hec;Choi, Yong-Ho;Lee, Han-Soo;Lee, Chang-Woo
    • Journal of Radiation Protection and Research
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    • v.27 no.1
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    • pp.21-26
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    • 2002
  • For the consideration of the influence on radioactive contamination of foods due to rain during the release period of radionuclides in a nuclear accident, the previous dynamic food chain model was improved. Wet interception coefficients for the agricultural plants were derived as a function of radionuclide and rainfall amount, and mathematical formula of the model was also re-established. In the results for the same time-integrated radioactive concentrations on the ground, radioactive contamination of foods decreased greatly by rainfall, and it decreased dramatically according to increasing rainfall amount. It means that predictive contamination in foods using the previous dynamic food chain model, in which dry interception to the agricultural plants is only considered, can be overestimated. Among radionuclides considering in this study ($^{137}Cs,\;^{90}Sr,\;^{131}I$), influence of rainfall for food contamination was the most sensitive to $^{131}I$, and the least sensitive to $^{90}Sr$.

Performance Evaluation of Advanced Municipal Wastewater Tretment by Phased Isolation Intrachannel Clarifier Ditch (침전지내장형 상분리 산화구공정에 의한 하수 고도처리특성 평가)

  • Hong, Ki-Ho;Chang, Duk;Han, Sang-Bae
    • Journal of Korean Society on Water Environment
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    • v.20 no.6
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    • pp.563-570
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    • 2004
  • Phased isolation intrachannel clarifier ditch process developed in this study is an enhanced biological nutrient removal process employing two ditches with intrachannel clarifiers. Bench-scale phased isolation ditch process was used to evaluate the system performance on municipal wastewater and detailed assessment of internal behavior in a ditch and each reactions. When the system was operated at the HRTs of 6~12hours, SRTs of 9~31 days, and cycle times of 4hours, the system showed removals of BOD, TN, and TP as high as 88~97%, 73~78%, and 65~90%, respectively. The internal behavior were well matched on each reactions such as nitrification, denitrification, and phosphorus release and uptake. As the SRT became longer, TN removal increased gradually, whereas TP removal decreased contrarily. However, the system was capable of producing an effluent TP concentration 1mg/L or less even at longer SRTs except the case of solids discharge by malfunction of intra-clarifier occurred by its geometrical limit. The system performance slightly decreased by hydraulic shock loading(increasing of influent flowrate and decreasing of system HRT). However, the higher system performance could be achieved again after four cycles. Thus, the system reliability could be successfully achieved short-term hydraulic shock loading that occurred in medium- and small-sized wastewater treatment plants suffering fluctuation of influent quality and flowrate during wet season.

Preparation and Stability of $Iodine-{\beta}-Cyclodextrin$ Inclusion Complex (요오드-${\beta}$-시클로덱스트린 포접 복합체의 제조 및 안정성)

  • Jee, Ung-Kil;Park, Kyung-Lae;Park, Mork-Soon;Baek, Myung-Ki;Park, Jin-Kyu
    • Journal of Pharmaceutical Investigation
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    • v.25 no.3
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    • pp.205-211
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    • 1995
  • To increase the solubility of iodine and iodine releasing agents, which are used widely as a topical broad spectrum antiseptics and disinfectant sanitizers, its inclusion complexes were prepared and studied. Inclusion complexes of iodine with ${\beta}-cyclodextrin$ were prepared by coprecipitation method and complex formation was acertained by differential scanning calorimetry and microscopic observation. Iodine content of inclusion complex was determined by means of iodometry. Tablets containing inclusion complex were manufactured with sugar, citric acid, magnesium stearate, dextrose. Stability of inclusion complexes and tablets was evaluated by accelerated stability test, and comparing with PVP-iodine. During preparation, use of 50% ethanol solution is preferable to water as the medium because the former resulted in more stable complex for a month under accelerated storage conditions. Solubility of iodine in KI aqueous solution was 0.048 g/ml and lower than in 50% ethanol solution. Inclusion complex and its tablets were very stable at severe condition for one month, and comparable to PVP-iodine in the aspect of stability. Inclusion complex tabletswere not affected with citric acid, sugar, dextrose, and direct tableting method was recommendable because wet granulation using ethanol gave some release of included iodine during process.

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Numerical simulation of localization of a sub-assembly with failed fuel pins in the prototype fast breeder reactor

  • Abhitab Bachchan;Puspendu Hazra;Nimala Sundaram;Subhadip Kirtan;Nakul Chaudhary;A. Riyas;K. Devan
    • Nuclear Engineering and Technology
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    • v.55 no.10
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    • pp.3648-3658
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    • 2023
  • The early localization of a fuel subassembly with a failed (wet rupture) fuel pin is very important in reactors to limit the associated radiological and operational consequences. This requires a fast and reliable system for failure detection and their localization in the core. In the Prototype Fast Breeder Reactor, the system specially designed for this purpose is Failed Fuel Location Modules (FFLM) housed in the control plug region. It identifies a failed sub-assembly by detecting the presence of delayed neutrons in the sodium from a failed sub-assembly. During the commissioning phase of PFBR, it is mandatory to demonstrate the FFLM effectiveness. The paper highlights the engineering and physics design aspects of FFLM and the integrated simulation towards its function demonstration with a source assembly containing a perforated metallic fuel pin. This test pin mimics a MOX pin of 1 cm2 of geometrical defect area. At 10% power and 20% sodium flow rate, the counts rate in the BCCs of FFLM system range from 75 cps to 145 cps depending upon the position of DN source assembly. The model developed for the counts simulation is applicable to both metal and MOX pins with proper values of k-factor and escape coefficient.