• Title/Summary/Keyword: Energy margin

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Evaluation of Operational Options of Wastewater Treatment Using EQPS Models (EQPS 모델을 이용한 하수처리장 운전 평가)

  • Yoo, Hosik;Ahn, Seyoung
    • Journal of the Korean Society of Urban Environment
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    • v.18 no.4
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    • pp.401-408
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    • 2018
  • EQPS (Effluent Quality Prediction System, Dynamita, France) was applied to analyze the appropriateness of the design of a bioreactor in A sewage treatment plant. A sewage treatment plant was designed by setting the design concentration of the secondary clarifier effluent to total nitrogen and total phosphorus, 10 mg/L and 1.8 mg/L, respectively, in order to comply with the target water quality at the level of the hydrophilic water. The retention time of the 4-stage BNR reactor was 9.6 hours, which was 0.5 for the pre-anoxic tank, 1.0 for the anaerobic tank, 2.9 for the anoxic tank, and 5.2 hours for the aerobic tank. As a result of the modeling of the winter season, the retention time of the anaerobic tank was increased by 0.2 hours in order to satisfy the target water quality of the hydrophilic water level. The default coefficients of the one step nitrification denitrification model proposed by the software manufacturer were used to exclude distortion of the modeling results. Since the process modeling generally presents optimal conditions, the retention time of the 4-stage BNR should be increased to 9.8 hours considering the bioreactor margin. The accurate use of process modeling in the design stage of the sewage treatment plant is a way to ensure the stability of the treatment performance and efficiency after construction of the sewage treatment plant.

Forecasting daily peak load by time series model with temperature and special days effect (기온과 특수일 효과를 고려하여 시계열 모형을 활용한 일별 최대 전력 수요 예측 연구)

  • Lee, Jin Young;Kim, Sahm
    • The Korean Journal of Applied Statistics
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    • v.32 no.1
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    • pp.161-171
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    • 2019
  • Varied methods have been researched continuously because the past as the daily maximum electricity demand expectation has been a crucial task in the nation's electrical supply and demand. Forecasting the daily peak electricity demand accurately can prepare the daily operating program about the generating unit, and contribute the reduction of the consumption of the unnecessary energy source through efficient operating facilities. This method also has the advantage that can prepare anticipatively in the reserve margin reduced problem due to the power consumption superabundant by heating and air conditioning that can estimate the daily peak load. This paper researched a model that can forecast the next day's daily peak load when considering the influence of temperature and weekday, weekend, and holidays in the Seasonal ARIMA, TBATS, Seasonal Reg-ARIMA, and NNETAR model. The results of the forecasting performance test on the model of this paper for a Seasonal Reg-ARIMA model and NNETAR model that can consider the day of the week, and temperature showed better forecasting performance than a model that cannot consider these factors. The forecasting performance of the NNETAR model that utilized the artificial neural network was most outstanding.

2020 Korean Dietary Reference Intakes for Protein: Estimation of protein requirements and the status of dietary protein intake in the Korean population (2020 단백질 섭취기준: 결핍과 만성질환 예방을 위한 한국인의 단백질 필요량 추정과 섭취현황)

  • Kim, Eunjung;Chung, Sangwon;Hwang, Jin-Taek;Park, Yoon Jung
    • Journal of Nutrition and Health
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    • v.55 no.1
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    • pp.10-20
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    • 2022
  • This article evaluated levels of Estimated Average Requirements (EARs), Reference Nutrient Intakes (RNIs), and Acceptable Macronutrient Distribution Ranges (AMDRs) of protein using the recently revised Dietary Reference Intakes (DRIs) for Koreans (2020). Dietary protein requirements are based on amounts sufficient to satisfy physiological demands to accomplish nitrogen equilibrium. The same principle was applied to estimate EARs and RNIs, for adults in DRIs conducted in 2015 and 2020 in Koreans. EAR was estimated to be 0.73 g/kg body weight/day, according to data (0.66 g/kg body weight/day) obtained using the nitrogen balance method and adjusted by efficiency of protein use (90%). RNI was calculated as EAR increased by an amount equal to twice the standard deviation of an age group so as to cover 97.5% of the group and was found to be 0.91 g/kg body weight/day. For weaned infants, children, and adolescents, growth requirement was added to estimate EAR. In particular, growth requirement was adjusted by efficiency of protein use in the revised EAR, which led to higher EARs for weaned infants, children, and adolescents of both genders as compared with 2015 DRIs. The AMDR for protein was set at 7%-20% of energy intake, which was the same as 2015 DRIs. Current, average protein intake by the Korean population is almost twice times the EAR, which suggests it might be better to increase the minimal margin for AMDR. However, it was not adjusted in this revision due to lack of evidence.

Mineral Chemistry of Cassiterite, Columbite, Tantalite and Associated Minerals from Soonkyoung Tin-bearing Pegmatite (순경(順鏡) 페그마타이트에서 산출(産出)되는 석석(錫石), 콜럼바이트, 탄탈라이트 및 수반광물(隨伴鑛物)에 대한 광물화학(鑛物化學))

  • Kim, Soo-Young;Moon, Hi-Soo;Park, No Young
    • Economic and Environmental Geology
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    • v.22 no.4
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    • pp.327-339
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    • 1989
  • Cassiterite, tantalite, columbite and tantalian rutile are found as accessory minerals in Soonkyoung tin-bearing pegmatites. These minerals occur as finely disseminated specks of up to micro-size in diameter and coarse grain size varying from 0.5-50mm in albite, muscovite and quartz assemblage. Cassiterite geneally shows a moderate to intense pleochroism, having a color brownish yellow to deep reddish brown. The substitution of $Ta^{+5}$, $Nb^{+5}$, $Ti^{+4}$ and Fe* for $Sn^{+4}$ in cassiterite ranges 0.01-0.10 mol%. The zoned cassiterite give a higher Ta/Nb ratios in margin than the ratios in core. This is due to the preferential $Ta^{+5}$ affinity to lower temperature during the crystallization of cassiterite. Tantalite-columbite and tantalian rutile occur in cassitertie with exsolution texture and/or infiltrate into the micro-fissures of cassiterite with micro quartz vein. The compositions of tantalite-columbite show the wide ranges of $Ta_2O_5$ : 14-46 wt.%, $Nb_2O_5$ : 60-28 wt. % and FeO*: 10.15 wt.%. The variation of chemical composition in tantalit-columbite exhibits the decreasing trends of $Mn^{+2}/M^{+2}+Fe^*$ with $Ta^{+5}/Ta^{+5}+Nb^{+5}$ increasing. These trends of vatiations indicate that the Ta/Nb fractionation are enhanced by higher Ta-complex activity in late stage of pegmatite consolidation and lower activity of F in agreements with the F-and Li-micas not to be developed in Soonkyoung tin-bearing pegmatite.

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Evaluation of the Efficiency of the Foxtail Millet Vacuum Cushion in Skin Cancer Radiation Treatment (자체 제작한 Foxtail Millet Vacuum Cushion의 광자선 피부암 치료 시 유용성 검증)

  • Choi, Shin-Cheol;Lee, Kyung-Jae;Jung, Sung-Min;Oh, Tae-Seong;Park, Jong-Il;Shin, Hyun-Kyo
    • The Journal of Korean Society for Radiation Therapy
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    • v.24 no.2
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    • pp.189-196
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    • 2012
  • Purpose: The sufficiency of skin dose and the reemergence of patient set-up position to the success of skin cancer radiation treatment is a very important element. But the conventional methods to increase the skin dose were used to vacuum cushion, bolus and water tank have several weak points. For this reason, we producted Foxtail Millet Vacuum Cushion and evaluated the efficiency of the Foxtail Millet Vacuum Cushion in skin cancer Radiation treatment. Materials and Methods: We measured absolute dose for 3 materials (Foxtail Millet Vacuum Cushion, bolus and solid water phantom) and compared each dose distribution. We irradiated 6 MV 100 MU photon radiation to every material of 1 cm, 2 cm, 3 cm thickness at three times. We measured absolute dose and compared dose distribution. Finally we inspected the CT simulation and radiation therapy planing using the Foxtail Millet Vacuum Cushion. Results: Absolute dose of Foxtail Millet Vacuum Cushion was similar to absolute dose of bolus and solid water phantom's result in each thickness. it Showed only the difference of 0.1~0.2% between each material. Also the same result in dose distribution comparison. About 97% of the dose distribution was within the margin of error in the prescribed ranges ($100{\pm}3%$), and achieved the enough skin dose (Gross Tumor Volume dose : $100{\pm}5%$) in radiation therapy planing. Conclusion: We evaluated important fact that Foxtail Millet Vacuum Cushion is no shortage of time to replace the soft tissue equivalent material and normal vacuum cushion at the low energy radiation transmittance. Foxtail Millet Vacuum Cushion can simultaneously achieve the enough skin dose in radiation therapy planing with maintaining normal vacuum cushion' function. Therefore as above We think that Foxtail Millet Vacuum Cushion is very useful in skin cancer radiation treatment.

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Geochemical Characteristics of Precambrian, Jurassic and Cretaceous Granites in Korea (한국(韓國)에 분포(分布)하는 선(先)캠브리아기(紀), 쥬라기(紀) 및 백악기화강암(白堊紀花崗岩)의 지화학적(地化學的) 특징(特徵))

  • Hong, Young Kook
    • Economic and Environmental Geology
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    • v.20 no.1
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    • pp.35-60
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    • 1987
  • The geochemical characteristics including minerals, major and trace elements chemistries of the Proterozoic, Jurassic and Cretaceous granites in Korea are systematically summarized and intended to decipher the origin and crystallization process in connection with the tectonic evolution. The granites in Korea are classified into three different ages of the granites with their own distinctive geochemical patterns: 1) Proterozoic granitoids; 2) Jurassic granites(cratonic and mobile belt); 3) Cretaceous-Tertiary granites. The Proterozoic granite gneisses (I-type and ilmenite-series) formed by metamorphism of the geochemically evolved granite protolith. The Proterozoic granites (S-type and ilmenite-series) produced by remobilization of sialic crust. The Jurassic granites (S-type and ilmenite-series) were mainly formed by partial melting of crustal materials, possibly metasedimentary rocks. The Cretaceous granites (I-type and magnetite-series) formed by fractional crystallization of parental magmas from the igneous protolith in the lower crust or upper mantle. The low temperature ($315{\sim}430^{\circ}C$) and small temperature variations (${\pm}20{\sim}30^{\circ}C$) in the cessation of exsolution of perthites for the Proterozoic and Jurassic granites might have been caused by slow cooling of the granites under regional metamorphic regime. The high ($520^{\circ}C$) and large temperature variations (${\pm}110^{\circ}C$) of perthites for the Cretaceous granites postulate that the rapid cooling of the granitic magma. In terms of the oxygen fugacity during the feldspar crystallization in the granite magmas, the Jurassic mobile belt granites were crystallized in the lowest oxygen fugacity condition among the Korean granites, whereas the Cretaceous granites in the Gyeongsang basin at the high oxygen fugacity condition. The Jurassic mobile belt granites are located at the Ogcheon Fold Belt, resulting by closing-collision situation such as compressional tectonic setting, and emplaced into a Kata-Mesozonal ductile crust. The Jurassic cratonic granites might be more evolved either during intrusion through thick crust or owing to lower degree of partial melting in comparison with the mobile belt granites. The Cretaceous granites are possibly comparable with a continental margin of Andinotype. Subduction of the Kula-Pacific ridge provided sufficient heat and water to trigger remelting at various subcrustal and lower crustal igneous protoliths.

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