• 제목/요약/키워드: LC20

검색결과 641건 처리시간 0.029초

선삭에 있어서의 피복, 비피복팁 및 방진장치가 절삭성에 미치는 영향에 관한 실험적 연구 (An Experimental Study on the Machinability Influenced by Coated and Uncoated Tips, and Damping Device in Turning)

  • 남준우
    • 한국정밀공학회지
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    • 제3권2호
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    • pp.62-75
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    • 1986
  • An experimental investigation of the machining characteristics such as cutt- ing resistance, surface roughness and tool wear in turning the test pieces of SM45C steel with both coated and uncoated carbide tool tips under various cutting conditions was conducted. Also a specially designed simple vibration damping device was experimentally evaluated for its effectiveness on machined surface roughness and a vibration test was conducted to confirm its ability to reduce the amplitude. Based on these tests finding, the following conclusions are made; 1. The cutting resistance($\textrm{p}_{1}$) increases as the depth of cut(d) increases at fixed feed rate(f) over the cutting speed(v) range of 43-226 m/min and p decreses about 18% average when V is increased for fixed d and f. At V= 226m/min, $\textrm{p}_{1}$/for A, C tips are about the same level but $\textrm{p}_{1}$ for B tip is 15% less than A, C tips. 2. The specific cutting resistance(Ks) at V=226 m/min was derived for A, B, C tips respectively and the value of Ks for B rip is about 20% less than A, C tips. 3. The surface roughness(Ra) improves significantly as the cutting speed(V) is increased and this effect was greater when V>100 m/min. On the other hand, Ra deteriorates as the feed rate(f) is increased and this trend was accelerated when f>0.3 mm/rev. With regard to the difference of Ra values among A, B, C tips, at V=226m/min, d=0.4mm, and f=0.31-0.61mm/rev, Ra values for B.C tips are about 17% less than tip A. 4. The experimental tool wear equations were derived for A, B, C tips and from these equations, the tool life($\textrm{T}_{\textrm{L}}$) baced on the I.S.O. criteria was calculated to be $\textrm{T}_{\textrm{L}}$<$\textrm{T}_{\textrm{LB}}$<$\textrm{T}_{\textrm{LC}}$ for both flank wear($\textrm{V}_{\textrm{B}}$) and boundary wear($\textrm{V}_{\textrm{N}}$). Hence, the coated tips are superior to the uncoated tip and tip C is considered to be the best. 5. The cutting resistance may be slightly reduced and the surface rounghness improved when the damper is used especially when V>100 m/min. Therefore this damping device is considered to be effective and practical. The experimental surface roughness equations were also derived. Based on the vibration test, it is established that the surface roughness improvement was the result of amplitude reduction made possible by the damper.

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건강기능식품 프랑스해안송껍질추출물 중 UPLC-MS/MS를 이용한 Ferulic acid, Caffeic acid, Catechin, Taxifolin 동시분석법 개발 연구 (Development of Simultaneous Analysis of Ferulic Acid, Caffeic Acid, Catechin and Taxifolin from Health Functional Food Pinus Pinaster Bark Extract by UPLC-MS/MS)

  • 오재명;김지안;허수정;최윤희;오금순
    • 한국식품위생안전성학회지
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    • 제34권5호
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    • pp.431-437
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    • 2019
  • 본 연구는 건강기능식품 프랑스해안송껍질추출물 중 catechin, caffeic acid, ferulic acid, taxifolin에 대한 동시분석법을 개발하는 연구이다. 최적분석조건을 확립하기 위해 시료 채취량, 용매 조건을 비교 검토하였으며, UPLC-MS/MS를 이용하여 각 4개 성분에 대한 정확한 분석 및 분석시간의 효율성도 향상하였다. 분석 시 사용한 컬럼은 Acquity UPLC BEH $C_{18}$이며, 정량이온으로 catechin, caffeic acid, ferulic acid, taxifolin 각각 133, 135, 245 및 248을 선정하였다. 확립된 시험법에 대해 특이성, 직선성, 검출한계, 정량한계, 정확성, 정밀성 등의 밸리데이션을 수행하였다. 4개 성분 모두 50-25000 mg/L 농도에서 결정계수(R2) 0.999이상으로 높은 직선성을 확인하였다. 또한 회수율은 84.9-104%이었고, 정밀성은 1.2-4.3%의 RSD를 확인하였다. 개발된 시험법은 프랑스해안송껍질추출물 중 catechin, caffeic acid, ferulic acid, taxifolin 분석을 위한 시험법으로 활용되기에 적합한 것으로 판단된다.

벤조피렌 기준 미설정 한약재의 오염도 조사 및 위해도 결정 (Investigation and Risk Characterization on the Contamination Level of Herbal Medicines Without Legal Benzo(a)pyrene Specification)

  • 박영애;고숙경;조석주;황인숙;신기영;문광덕
    • 생약학회지
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    • 제52권4호
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    • pp.219-227
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    • 2021
  • By analysing the benzo(a)pyrene concentration using HPLC-FLD and LC-MS/MS, pollution levels of herbal medicines without permitted benzo(a)pyrene specification were investigated. Average benzo(a)pyrene concentrations were 38.30, 37.46 and 21.22 ㎍/kg for Amomi Tsao-ko Fructus, Mume Fructus and Coptidis Rhizoma, respectively, which are 4 to 7 times higher than maximum permitted benzo(a)pyrene concentration of Rehmanniae Radix Preparata and Rehmanniae Radix, i.e. 5.0 ㎍/kg. Proportion of detected samples exceeding 5.0 ㎍/kg benzo(a)pyrene concentration was 22% for Cimicifugae Rhizoma and Scrophulariae Radix, 44% for Forsythiae Fructus, 67% for Mume Fructus, 100% for Amomi Tsao-ko Fructus and Coptidis Rhizoma, and collectively 29% (36 out of 125 samples) in average. In terms of risk characterization results, human exposure of benzo(a)pyrene were 7.96, 3.49 and 1.61 ng/kg b.w./day and the margin of exposure(MOE) were 1.25 × 104, 2.86 × 104 and 6.20 × 104 for Mume Fructus, Amomi Tsao-ko Fructus and Coptidis Rhizoma, respectively. MOE banding of those herbal medicines was categorized to 'low concern'. However, considering that human exposure of benzo(a)pyrene for food is legislated to 1.4~2.5 ng/kg b.w./day, it was urgent to set up the guideline of benzo(a)pyrene in herbal medicines.

High frequency somatic embryogenesis and plant regeneration of interspecific ginseng hybrid between Panax ginseng and Panax quinquefolius

  • Kim, Jong Youn;Adhikari, Prakash Babu;Ahn, Chang Ho;Kim, Dong Hwi;Kim, Young Chang;Han, Jung Yeon;Kondeti, Subramanyam;Choi, Yong Eui
    • Journal of Ginseng Research
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    • 제43권1호
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    • pp.38-48
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    • 2019
  • Background: Interspecific ginseng hybrid, Panax ginseng ${\times}$ Panax quenquifolius (Pgq) has vigorous growth and produces larger roots than its parents. However, F1 progenies are complete male sterile. Plant tissue culture technology can circumvent the issue and propagate the hybrid. Methods: Murashige and Skoog (MS) medium with different concentrations (0, 2, 4, and 6 mg/L) of 2,4-dichlorophenoxyacetic acid (2,4-D) was used for callus induction and somatic embryogenesis (SE). The embryos, after culturing on $GA_3$ supplemented medium, were transferred to hormone free 1/2 Schenk and Hildebrandt (SH) medium. The developed taproots with dormant buds were treated with $GA_3$ to break the bud dormancy, and transferred to soil. Hybrid Pgq plants were verified by random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) analyses and by LC-IT-TOF-MS. Results: We conducted a comparative study of somatic embryogenesis (SE) in Pgq and its parents, and attempted to establish the soil transfer of in vitro propagated Pgq tap roots. The Pgq explants showed higher rate of embryogenesis (~56% at 2 mg/L 2,4-D concentration) as well as higher number of embryos per explants (~7 at the same 2,4-D concentration) compared to its either parents. The germinated embryos, after culturing on $GA_3$ supplemented medium, were transferred to hormone free 1/2 SH medium to support the continued growth and kept until nutrient depletion induced senescence (NuDIS) of leaf defoliation occurred (4 months). By that time, thickened tap roots with well-developed lateral roots and dormant buds were obtained. All Pgq tap roots pretreated with 20 mg/L $GA_3$ for at least a week produced new shoots after soil transfer. We selected the discriminatory RAPD and ISSR markers to find the interspecific ginseng hybrid among its parents. The $F_1$ hybrid (Pgq) contained species specific 2 ginsenosides (ginsenoside Rf in P. ginseng and pseudoginsenosides $F_{11}$ in P. quinquefolius), and higher amount of other ginsenosides than its parents. Conclusion: Micropropagation of interspecific hybrid ginseng can give an opportunity for continuous production of plants.

인천광역시 유통 농산물의 최근 3년간 잔류농약 실태조사 (A Survey on the Residual Pesticides on Agricultural Products on the Markets in Incheon from 2016 to 2018)

  • 박정은;이미연;김선회;송성민;박병규;서순재;송재용;허명제
    • 한국환경농학회지
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    • 제38권3호
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    • pp.205-212
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    • 2019
  • BACKGROUND: This survey conducted on agricultural products in Incheon for the past three years from 2016 to 2018 to detect residual pesticides and to monitor the use of pesticides. METHODS AND RESULTS: Residual pesticides were analyzed for a total of 5,937 agricultural products in Samsan wholesale market, traditional market and large retailers in Incheon. Samples were analyzed by multi class pesticide method using GC-MS/MS, LC-MS/MS, GC-ECD/NPD, and UHPLC. In 59 cases (1.0%) residual pesticides were detected improperly and these cases exceeded maximum residue limits (MRLs). CONCLUSION: The ratios of violative agricultural products were similar each year at approximately 1.0% per year, but the residual pesticide detection rates with the limit included in the samples were shown to be gradually decreasing to 17.9%, 12.6%, and 11.2% annually. The frequency of violative residual pesticides was high in order of Diazinon, Chlorpyrifos, Iprodione, etc. Residual pesticide monitoring might be needed in the future continuously, as violations in agricultural products distributed in Incheon are shown at a similar level every year.

인공환경 생육조건에서의 Amorphopallus paeoniifolius: Leaf Cycle (Amorphopallus Paeoniifolius in Greenhouse Environment: Leaf Cycle)

  • 안태현;고여빈;배준규;이정호;이기철
    • 한국자원식물학회:학술대회논문집
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    • 한국자원식물학회 2019년도 추계학술대회
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    • pp.48-48
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    • 2019
  • Amorphophallus paeoniifolius (Dennst.) Nicolson는 영명으로 Elephant yam 또는 Whitespot giant arum 으로 불리는 천남성과(Araceae) 식물로 동아시아, 뉴기니, 오세아니아, 마다가스카르 등지에서 자생하고 있으며 숲의 가장자리 또는 2차림에서 발견 된다. 다년생 식물로 덩이줄기는 어두운 갈색의 둥근모양으로 직경 20~25 cm로 자라고 수염뿌리가 사방으로 달린다. IUCN 적색목록(Red List)에 관심대상 종(LC: Least Concern)에 속하는 식물이다. 현지인들은 마(Dioscorea Polystachya Turcz.)처럼 채소로 먹기도 하며 약용으로 쓰이기도 하는데 복부장애, 소화불량, 천식, 기관지염, 빈혈 등에 약효가 있다. Amorphophallus paeoniifolius은 $25^{\circ}C{\sim}35^{\circ}C$, 연강수량 1,000~1,500 mm에서 잘 자란다. 가운데 눈이 올라오면서 생장을 시작하고 며칠이 지나서야 잎 또는 꽃으로 자라는지 알 수 있다. 잎의 생육주기는 잎눈이 생장을 시작하면 잎자루 끝에 소엽과 소잎자루가 접힌 채로 올라온다. 소엽들이 펴지면서 완전한 모습을 갖추는데 30일 이상의 생장기간을 갖는다. 잎의 형태는 우상복엽(pinnate compound leaf)으로 우산처럼 보이는 잎 하나로 광합성을 한다. 잎은 최대 높이 2.5~3 m, 너비 3 m까지 자라며, 잎자루의 색은 녹색과 청색으로 얼룩덜룩한 무늬가 있다. 인공환경 조건에서 Amorphophallus paeoniifolius 생활사 중 잎의 주기를 연구하기 위해서 광, 온도 등의 지상부 환경은 열대 및 아열대 식물의 자생지와 유사하게 조성하였고, 지하부 환경은 인공 배합토를 사용하여 조성하였다. 평균온도는 $25{\sim}28^{\circ}C$, 겨울철 최저 $16^{\circ}C$, 여름철 최고 $33^{\circ}C$를 유지 관리 하였다. 자동 환경제어시스템으로 온도 및 환기를 유지 관리하고 필요에 따라 수동제어 관리를 병행하여 조절하였다. Amorphophallus paeoniifolius는 잎을 먼저 생성하고 광합성으로 생산된 영양물질을 덩이뿌리에 저장을 하고 그 영양물질을 이용하여 꽃을 피우는 생육 특성을 지닌다. 실험에 사용된 공시 식물은 2018년 12월 미얀마에서 생체(덩이줄기) 형태로 도입되었다. 화분에 식재 후 약 5개월이 지난 시점에서 잎의 생장이 시작되었다. 2019년 7월 29일 기준으로 높이 80 cm, 너비 60 cm의 크기로 성장하였으며, 생육환경에 따라 3~5개월 뒤 잎이 지고 나면 다시 덩이줄기로 되돌아갈 것으로 판단된다. 하지만 지금까지 이 식물에 알려진 정보는 인공환경에서의 연구가 아닌 자연환경에서의 연구결과이기 때문에 인공적인 온실 환경에서 자란 Amorphophallus paeoniifolius는 잎의 주기는 더 오래 갈 수도 있으며 꽃의 주기 또한 느리거나 빠를 수 있다. 잎의 생장주기(Leaf Cycle)시 잎자루가 낮과 밤의 방향을 달리 하여 자라는 것이 관찰되었다. 이는 광합성을 위해서 잎자루의 방향을 햇빛 방향으로 돌리는 것으로 판단된다. Amorphophallus paeoniifolius를 실내 조경 식물 또는 식 약용의 소재식물로 활용하기 위해서는 꽃의 생장주기 등 추가적인 모니터링과 연구가 필요하다.

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중금속 농도가 섬초롱꽃 종자 발아 및 유근 발달에 미치는 영향 (Effects of Heavy Metal Concentrations on Seed Germination and Rhizome Development of Campanula takesimana Nakai)

  • 김태현;김도현;임현정;최규성;김상근;송치현;오범석;김양수;송기선;원창오
    • 한국자원식물학회:학술대회논문집
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    • 한국자원식물학회 2019년도 추계학술대회
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    • pp.39-39
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    • 2019
  • 섬초롱꽃은 울릉군에 한정적으로 분포하는 여러해살이풀이다. 산림청에서는 약관심종(LC) 등급의 희귀식물이자 특산식물로 분류하고 있으며, 꽃의 관상가치가 특히 높아 화단용 소재, 절화용, 화분재배 등으로 흔히 이용되고 있다. 따라서 본 연구는 섬초롱꽃의 대량증식 시, 중금속이 미칠 수 있는 영향에 대해 파악하고자 수행하였다. 실험에 사용한 중금속은 카드뮴(Cd), 철(Fe) 두 종류이며, 두 종류 모두 1% 한천(agar)배지에 10, 25, 50, 100, 200 mg/L 농도로 녹여 사용하였다. 발아율 및 유근 생장을 위해 종자 및 유묘를 치상 후, $25^{\circ}C$ 항온 생장상에서 발아율 및 유근 발달을 관찰하였다. 발아율 측정결과, 아무처리도하지 않은 1% 한천(agar) 배지에서 $62.7{\pm}7.4%$로 가장 높았고 중금속 농도가 높아질수록 감소하였다. 카드뮴(Cd) 처리구에서는 10, 25, 50, 100, 200 mg/L 농도에서 각각 $17.3{\pm}1.3$, $2.7{\pm}1.3$, $1.3{\pm}1.3$, 0, 0%로 나타났다. 한편, 철(Fe) 처리구에서는 10, 25, 50, 100, 200 mg/L 농도에서 각각 $46.7{\pm}4.8$, $24.0{\pm}2.3$, $36.0{\pm}6.9$, $20.0{\pm}2.3$, 0%로 나타났다. 유근의 평균 생장 길이(mm)는 아무처리도 하지 않은 1% 한천(agar) 배지에서 19.6 mm로 가장 높았고, 중금속 농도가 높아질수록 낮게 나타났다. 카드뮴(Cd) 처리구에서는 10, 25, 50, 100, 200 mg/L 농도에서 각각 4.6 mm, 1.9 mm, 0.7 mm, 0.9 mm, 0 mm 생장한 것으로 나타났다. 한편, 철(Fe) 처리구에서는 10, 25, 50, 100, 200 mg/L 농도에서 각각 15.9 mm, 8.6 mm, 8.1 mm, 0.9 mm, 0 mm 생장한 것으로 나타났다. 실험결과를 종합해 볼 때, 섬초롱꽃 종자 발아 및 유근 생장의 억제는 카드뮴(Cd) 처리구에서 높게 나타났고, 철(Fe) 처리구에서는 비교적 영향을 덜 미치는 것으로 나타났다. 특히 카드뮴은 10 mg/L 농도만 처리하더라도 약 3.6~4.2배의 발아율 생장율 감소가 나타나, 섬초롱꽃 대량증식 시, 치명적일 것으로 판단된다. 본 실험의 결과는 섬초롱꽃 종자를 이용한 대량증식 및 유묘재배에 있어, 토양을 선택하는데 중요한 기초자료로서 활용될 것으로 기대된다.

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자동화 HPLC/SPE/HPLC 시스템(Sepbox system)을 활용한 고추 잎 (leaf of Capsicum annuum L.) 추출물 분리 및 α-glucosidase 억제 활성 물질 탐색 (Rapid separation of Capsicum annuum L. leaf extract using automated HPLC/SPE/HPLC coupling system (Sepbox system) and identification of α-glucosidase inhibitory active substances)

  • 김민선;진종범;이정환;안혜숙;판철호;박진수
    • Journal of Applied Biological Chemistry
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    • 제64권1호
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    • pp.25-32
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    • 2021
  • 식물 유래 화합물은 다양한 생리활성과 구조 다양성으로 많은 연구자에게 관심을 받고 있으나 화합물 분리는 많은 시간 소요, 과량의 유기용매 소모와 분리과정 중의 활성성분의 유실 등의 어려움을 겪게 된다. 이러한 점을 극복하기 위하여 HPLC/SPE/HPLC를 결합한 Sepbox 분리시스템을 이용하여 고추잎 추출물에서 288개 분획물을 획득하였고 이 중에서 alpha-glucosidase 저해효능을 가지는 화합물인 luteolin 7-O-glucoside를 효과적으로 확인할 수 있었다. 또한 고추잎에 풍부한 플라보노이드 다당체를 가수분해함에 따라 해당 활성이 증가함을 검증하였다. 그러므로 본 연구결과는 Sepbox 시스템이 생리활성 평가와 결합할 경우 식물 내 유용물질 탐색에 효과적임을 보여주었다.

인동(忍冬) 열수 추출물의 항산화 효과 및 HCl-Ethanol로 유도된 위염 동물 모델에서의 위 점막 손상 보호 효과 (The Gastroprotective and Antioxidative Effects of Lonicera japonica water extract on HCl/ethanol-induced Gastric Mucosa Damage in Rats)

  • 심미옥;이현주;장지훈;정호경;양버들;우경완;황태연;김선영;노종현;조현우
    • 대한본초학회지
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    • 제34권6호
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    • pp.57-62
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    • 2019
  • Objective : Gastritis is a major complication of gastrointestinal disease. Lonicera japonica is used in folk medicine to treat different diseases such as exopathogenic wind-heat, epidemic febrile diseases, sores, carbuncles and some infectious diseases. Therefore, this study examined the effects of Lonicera japonica water extract (LJE) on HCl/ethano-linduced acute gastric ulceration and anti-oxidants properties. Methods : LC-ESI-IT-TOF MS was employed for rapid identification of major compound from LJE. The antioxidant activities were evaluated through total polyphenol and flavonoid contents and radical scavenging assays and superoxide dismutase (SOD)-like activity. SD rats were randomly divided into five different groups including the normal group, ulcer group, positive group (20 kg/mg of omeprazole, ip), and experimental groups (100 kg/mg and 500 kg/mg of LJE, ip). Results : 4,5-Dicaffeoyl quinic acid, loganic acid, secologanic acid, sweroside, loganin, vogeloside were identified based on the detection of the molecular ion with those of literature data. The LJE was possessed free radical scavenging activities such as DPPH (IC50=189.7 ㎍/㎖), ABTS (IC50=164.5 ㎍/㎖), and SOD-like activity (IC50=405.02 ㎍/㎖). Macroscopic and histological analyses showed LJE treated group were significantly reduced to an extent that it allowed leukocytes penetration of the gastric walls compared with the ulcer group. In addition, an ulcer inhibition rate and prostaglandin E2 levels were increased in rats treated with LJE. Conclusion : The present study has demonstrated the antioxidantive and gastroprotective effect of LJE, these findings suggested that LJE has the potential for use in treatment of gastric disorders.

Application of Artificial Intelligence Technology for Dam-Reservoir Operation in Long-Term Solution to Flood and Drought in Upper Mun River Basin

  • Areeya Rittima;JidapaKraisangka;WudhichartSawangphol;YutthanaPhankamolsil;Allan Sriratana Tabucanon;YutthanaTalaluxmana;VarawootVudhivanich
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2023년도 학술발표회
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    • pp.30-30
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    • 2023
  • This study aims to establish the multi-reservoir operation system model in the Upper Mun River Basin which includes 5 main dams namely, Mun Bon (MB), Lamchae (LC), Lam Takhong (LTK), Lam Phraphoeng (LPP), and Lower Lam Chiengkrai (LLCK) Dams. The knowledge and AI technology were applied aiming to develop innovative prototype for SMART dam-reservoir operation in future. Two different sorts of reservoir operation system model namely, Fuzzy Logic (FL) and Constraint Programming (CP) as well as the development of rainfall and reservoir inflow prediction models using Machine Learning (ML) technique were made to help specify the right amount of daily reservoir releases for the Royal Irrigation Department (RID). The model could also provide the essential information particularly for the Office of National Water Resource of Thailand (ONWR) to determine the short-term and long-term water resource management plan and strengthen water security against flood and drought in this region. The simulated results of base case scenario for reservoir operation in the Upper Mun from 2008 to 2021 indicated that in the same circumstances, FL and CP models could specify the new release schemes to increase the reservoir water storages at the beginning of dry season of approximately 125.25 and 142.20 MCM per year. This means that supplying the agricultural water to farmers in dry season could be well managed. In other words, water scarcity problem could substantially be moderated at some extent in case of incapability to control the expansion of cultivated area size properly. Moreover, using AI technology to determine the new reservoir release schemes plays important role in reducing the actual volume of water shortfall in the basin although the drought situation at LTK and LLCK Dams were still existed in some periods of time. Meanwhile, considering the predicted inflow and hydrologic factors downstream of 5 main dams by FL model and minimizing the flood volume by CP model could ensure that flood risk was considerably minimized as a result of new release schemes.

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