• Title/Summary/Keyword: Correlation Range

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Occurrence of Uranium-238 and Rn-222 in Groundwater and Its Relationship with Helium Isotope (지하수 내 우라늄-238 및 라돈-222 산출과 헬륨 동위원소와의 상관성 연구)

  • Jeong, Chan Ho;Lee, Yu Jin;Lee, Yong Cheon;Hong, Jin Woo;Kim, Cheon Hwan;Nagao, Keisuke;Kim, Young-Seog;Kang, Tae-Seob
    • The Journal of Engineering Geology
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    • v.31 no.4
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    • pp.659-669
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    • 2021
  • The purpose of this study is to elucidate the relationship between occurrence of natural radioactive materials such as 238U and 222Rn and original mixing ratio of helium isotope of groundwater from various geology, and to suggest the underground aquifer environment from helium original mixing data. 9 groundwater samples were collected from five study areas, and 238U, Rn-222 and helium isotope were analyzed. A high 238U content of the range of 218~477 ㎍ /L in the groundwater occurs in the twomica granite. 4He air-crust mixing ratio and the Rn-222 content show a rough relation, that is, Rn-222 content increases according to the increase of 4He crust mixing ratio. Because of helium and radon are an inert gas, their behavior in underground environment is assumed as an analogous. The 238U content and He isotope in groundwater does not show any distinct correlation. The groundwater can be classified as three groups (air, air-crust mixing, crust-mantle mixing origin) on the diagram of 3He/4He vs 4He/20Ne, which is composed of original mixing line from air-crust-mantle end members. This original mixing of helium can provide the information of underground aquifer characteristic such as the connection with surface environment or isolation condition from air environment.

Analysis of Chlorophyll-a and Algal Bloom Indices using Unmanned Aerial Vehicle based Multispectral Images on Nakdong River (무인항공기 기반 다중분광영상을 이용한 낙동강 Chlorophyll-a 및 녹조발생지수 분석)

  • KIM, Heung-Min;CHOE, Eunyoung;JANG, Seon-Woong
    • Journal of the Korean Association of Geographic Information Studies
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    • v.25 no.1
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    • pp.101-119
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    • 2022
  • Existing algal bloom monitoring is based on field sampling, and there is a limit to understanding the spatial distribution of algal blooms, such as the occurrence and spread of algae, due to local investigations. In this study, algal bloom monitoring was performed using an unmanned aerial vehicle and multispectral sensor, and data on the distribution of algae were provided. For the algal bloom monitoring site, data were acquired from the Mulgeum·Mae-ri site located in the lower part of the Nakdong River, which is the areas with frequent algal bloom. The Chlorophyll-a(Chl-a) value of field-collected samples and the Chl-a estimation formula derived from the correlation between the spectral indices were comparatively analyzed. As a result, among the spectral indices, Maximum Chlorophyll Index (MCI) showed the highest statistical significance(R2=0.91, RMSE=8.1mg/m3). As a result of mapping the distribution of algae by applying MCI to the image of August 05, 2021 with the highest Chl-a concentration, the river area was 1.7km2, the Warning area among the indicators of the algal bloom warning system was 1.03km2(60.56%) and the Algal Bloom area occupied 0.67km2(39.43%). In addition, as a result of calculating the number of occurrence days in the area corresponding to the "Warning" in the images during the study period (July 01, 2021~November 01, 2021), the Chl-a concentration above the "Warning" level was observed in the entire river section from 12 to 19 times. The algal bloom monitoring method proposed in this study can supplement the limitations of the existing algal bloom warning system and can be used to provide information on a point-by-point basis as well as information on a spatial range of the algal bloom warning area.

The Influence of Soil Characteristics and Sweet Potato (Ipomoea batatas L.) Varieties on Fiber Content (재배지역 토양특성과 고구마 품종의 섬유질 함량 차이)

  • Park, Won;Chung, Mi Nam;Lee, Hyeong-Un;Kim, Tae Hwa;Kim, Su Jung;Nam, Sang Sik
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.67 no.3
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    • pp.172-179
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    • 2022
  • Sweet potato varieties with high fiber content in the storage root have poor texture when steamed or roasted. This study investigates the difference in fiber content among sweet potato varieties by soil and climate. The average fiber content of 'Hogammi', 'Sodammi', 'Pungwonmi', 'Danjami', and 'Jinyulmi' cultivars from the samples collected at farms in Haenam, Muan, and Unbong, Korea were 95.71, 66.73, 44.55, 40.55, and 38.53 mg/100g FW, respectively. There was no significant difference between site-specific conditions and varieties. Based on the degree of visual fibrousness, 'Hogammi' has an average of 3.6-4.0 with many thick stringy fibers. The fiber content of the 'Hogammi' cultivar was measured across 19 sites representing the main sweet potato growing regions of Korea. The fiber content was between 115.82 and 114.6 mg/100g in Haenam 2 and Boryeong 1, and 87.46 mg/100g in Hamyang. However, the fiber content at the remaining 16 sites was within the range of 94.63-108.52 mg/100g, although there were some site-level differences. The fiber content of the sweet potato storage roots were positively correlated with soil phosphorus (R2 = 0.58**), organic matter (R2 = 0.52*), and pH (R2 = 0.51*), which had a significance of 1% and 5%. The fiber content of sweet potato storage roots was found to have increased with increasing phosphorus content, organic matter and pH in the soil. However, there was no correlation with the amount of precipitation, days of precipitation and hours of sunshine with the fiber content of sweet potato at the selected sites.

Spatio-Temporal Variation Characteristics of Primary Productivity and Environmental Factors of Shellfish Mariculture in Jaran Bay, Korea (자란만 패류양식어장의 기초생산력 및 환경인자 변동 특성)

  • Lee, Dae In;Choi, Yong-Hyeon;Hong, SokJin;Kim, Hyung Chul;Lee, Won-Chan
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.28 no.5
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    • pp.721-734
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    • 2022
  • This study analyzed the spatio-temporal variation characteristics of major environmental factors such as primary productivity (PP), chlorophyll a, nutrients, sinking particle matters, and organic contamination and biochemical composition of surface sediment on a monthly basis for approximately 2 years around shellfish mariculture in Jaran Bay, Korea. In addition, PP in Jaran Bay was compared with that in other coastal areas and related policy plans were proposed. The average PP of the study area was high in summer and autumn with 6.43~115.43 mgC m-2 hr-1 range. This was lower than that in Gamak Bay and Masan Bay, whereas higher than that in Garorim Bay and the West Sea. The PP in coastal waters, where many aquaculture farms were distributed, significantly fluctuated. The different size compositions of phytoplanktons constituting chlorophyll a slightly varied by month, and little restriction existed on the productivity of phytoplanktons owing to the depletion of nutrients. Typically, the Redfield ratio was less than 16, indicating that nitrogen was the limiting factor for the growth of phytoplanktons. The biochemical composition of particulate organic matters in the water column showed the highest carbohydrates, but lipids and protein contents were high in surface sediments. The concentration of TOC and AVS of the surface sediments was high at inside of bay, and sometimes, exceeded the environmental criteria of fishing grounds. The organic C:N ratio of sediments ranged from 8.1 to 10.4 on average. PP had the highest correlation with chlorophyll a, nitrogen and protein of particle organic materials. Recently, chlorophyll a, DIN, and DIP of water column trends tended to decrease, however, the contamination of sediments increased. Considering the annual PP of 125.9 gC m-2 yr-1 and mariculture area (oyster) of 4.97 km2, the annual carbon production from phytoplanktons was estimated to be about 625 tons, and the annual total wet weight of shellfish (oyster) was estimated to be about 6,250 tons.

Characteristics on spatial distributions of phytoplankton communities in relation to water masses in the western South Sea, Korea in early autumn 2021 (2021년 이른 가을 남해 서부 해역의 수괴 분포 및 식물플랑크톤 군집의 공간분포 특성)

  • Yang Ho Yoon
    • Korean Journal of Environmental Biology
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    • v.39 no.4
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    • pp.559-572
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    • 2021
  • A survey was conducted to analyze water masses and spatial distributions of phytoplankton communities at 15 stations on the surface and chlorophyll a maximum layers (CML) in the western South Sea of Korea from September 8 to 9, 2021. As a result, water masses were classified into Coastal Waters (CW) with relatively low salinity, the Tsushima Warm Current (TWC) with high water temperature and high salinity, and mixed waters (MW) showing a mixture of these two water masses. Turbidity showed high concentration in both the surface and CML. The chlorophyll a concentration was as low as 0.90±0.43 ㎍ L-1 in the surface, more than 1.1 ㎍ L-1 in CW, around 1.0 ㎍ L-1 in MW, and less than 0.5 ㎍ L-1 in the TWC. CML was 1.64±0.54 ㎍ L-1. Regarding species composition of phytoplankton communities, there were 57 species in 31 genera(diatoms, 57.8%; dinoflagellates, 35.1%; and other phytoflagellates, 7.1%). The phytoplankton standing crop had 4.6±7.6 cells mL-1 in the surface, more than 30 cells mL-1 in the CW, 2-5 cells mL-1 in the MW, and less than 2 cells mL-1 in the TWC. CML was slightly higher than the surface with a variation of 5.7±8.4 cells mL-1. Dominant species were found to be Rhizosolenia flagilissima f. flagilissima, Skeletonema costatum-ls, and Nitzschia sp./ small size in the surface. For the CML Rh. flagilisima f. flagilissima showed a dominance of 12.0%. For the surface, the diversity variation was 2.36±0.40, which was high for TWC but low for MW. For CML, the diversity variation was 2.29±0.52, which was slightly lower than that of the surface. The dominance in the surface was 0.50±0.15, with a fluctuation range of more than 0.5 in MW and less than 0.5 in the TWC, which was different from the diversity. According to correlation analysis and principal component analysis (PCA), the presence of phytoplankton standing crops was high in CW but low in MW and TWC. That is, phytoplankton communities in early autumn were strongly affected by the expansion and mixing of water masses in western South Sea.

Verification of Multi-point Displacement Response Measurement Algorithm Using Image Processing Technique (영상처리기법을 이용한 다중 변위응답 측정 알고리즘의 검증)

  • Kim, Sung-Wan;Kim, Nam-Sik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.3A
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    • pp.297-307
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    • 2010
  • Recently, maintenance engineering and technology for civil and building structures have begun to draw big attention and actually the number of structures that need to be evaluate on structural safety due to deterioration and performance degradation of structures are rapidly increasing. When stiffness is decreased because of deterioration of structures and member cracks, dynamic characteristics of structures would be changed. And it is important that the damaged areas and extent of the damage are correctly evaluated by analyzing dynamic characteristics from the actual behavior of a structure. In general, typical measurement instruments used for structure monitoring are dynamic instruments. Existing dynamic instruments are not easy to obtain reliable data when the cable connecting measurement sensors and device is long, and have uneconomical for 1 to 1 connection process between each sensor and instrument. Therefore, a method without attaching sensors to measure vibration at a long range is required. The representative applicable non-contact methods to measure the vibration of structures are laser doppler effect, a method using GPS, and image processing technique. The method using laser doppler effect shows relatively high accuracy but uneconomical while the method using GPS requires expensive equipment, and has its signal's own error and limited speed of sampling rate. But the method using image signal is simple and economical, and is proper to get vibration of inaccessible structures and dynamic characteristics. Image signals of camera instead of sensors had been recently used by many researchers. But the existing method, which records a point of a target attached on a structure and then measures vibration using image processing technique, could have relatively the limited objects of measurement. Therefore, this study conducted shaking table test and field load test to verify the validity of the method that can measure multi-point displacement responses of structures using image processing technique.

Estimation of the Surface Currents using Mean Dynamic Topography and Satellite Altimeter Data in the East Sea (평균역학고도장과 인공위성고도계 자료를 이용한 동해 표층해류 추산)

  • Lee, Sang-Hyun;Byun, Do-Seong;Choi, Byoung-Ju;Lee, Eun-Il
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.14 no.4
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    • pp.195-204
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    • 2009
  • In order to estimate sea surface current fields in the East Sea, we examined characteristics of mean dynamic topography (MDT) fields (or mean surface current field, MSC) generated from three different methods. This preliminary investigation evaluates the accuracy of surface currents estimated from satellite-derived sea level anomaly (SLA) data and three MDT fields in the East Sea. AVISO (Archiving, Validation and Interpretation of Satellite Oceanographic data) provides a MDT field derived from satellite observation and numerical models with $0.25^{\circ}$ horizontal resolution. Steric height field relative to 500 dbar from temperature and salinity profiles in the East Sea supplies another MDT field. Trajectory data of surface drifters (ARGOS) in the East Sea for 14 years provide another MSC field. Absolute dynamic topography (ADT) field is calculated by adding SLA to each MDT. Application of geostrophic equation to three different ADT fields yields three surface geostrophic current fields. Comparisons were made between the estimated surface currents from the three different methods and in-situ current measurements from a ship-mounted ADCP (Acoustic Doppler Current Profiler) in the southwestern East Sea in 2005. For offshore areas more than 50 km away from the land, the correlation coefficients (R) between the estimated versus the measured currents range from 0.58 to 0.73, with 17.1 to $21.7\;cm\;s^{-1}$ root mean square deviation (RMSD). For coastal ocean within 50 km from the land, however, R ranges from 0.06 to 0.46 and RMSD ranges from 15.5 to $28.0\;cm\;s^{-1}$. Results from this study reveal that a new approach in producing MDT and SLA is required to improve the accuracy of surface current estimations for the shallow costal zones of the East Sea.

Optimization and Applicability Verification of Simultaneous Chlorogenic acid and Caffeine Analysis in Health Functional Foods using HPLC-UVD (HPLC-UVD를 이용한 건강기능식품에서 클로로겐산과 카페인 동시분석법 최적화 및 적용성 검증)

  • Hee-Sun Jeong;Se-Yun Lee;Kyu-Heon Kim;Mi-Young Lee;Jung-Ho Choi;Jeong-Sun Ahn;Jae-Myoung Oh;Kwang-Il Kwon;Hye-Young Lee
    • Journal of Food Hygiene and Safety
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    • v.39 no.2
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    • pp.61-71
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    • 2024
  • In this study, we analyzed chlorogenic acid indicator components in preparation for the additional listing of green coffee bean extract in the Health Functional Food Code and optimized caffeine for simultaneous analysis. We extracted chlorogenic acid and caffeine using 30% methanol, phosphoric acid solution, and acetonitrile-containing phosphoric acid and analyzed them at 330 and 280 nm, respectively, using liquid chromatography. Our analysis validation results yielded a correlation coefficient (R2) revealing a significance level of at least 0.999 within the linear quantitative range. The chlorogenic acid and caffeine detection and quantification limits were 0.5 and 0.2 ㎍/mL and 1.4, and 0.4 ㎍/mL, respectively. We confirmed that the precision and accuracy results were suitable using the AOAC validation guidelines. Finally, we developed a simultaneous chlorogenic acid and caffeine analysis approach. In addition, we confirmed that our analysis approach could simultaneously quantify chlorogenic acid and caffeine by examining the applicability of each formulation through prototypes and distribution products. In conclusion, the results of this study demonstrated that the standardized analysis would expectably increase chlorogenic acidcontaining health functional food quality control reliability.

Quantification of the Elastic Property of Normal Thigh Muscles Using MR Elastography: Our Initial Experience (자기 공명 탄성 검사를 이용한 대퇴 근육의 탄성도의 정량화: 초기 경험)

  • Junghoon Kim;Jeong Ah Ryu;Juhan Lee
    • Journal of the Korean Society of Radiology
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    • v.82 no.6
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    • pp.1556-1564
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    • 2021
  • Purpose This study aimed to apply MR elastography (MRE) to achieve in vivo evaluation of the elastic properties of thigh muscles and validate the feasibility of quantifying the elasticity of normal thigh muscles using MRE. Materials and Methods This prospective study included 10 volunteer subjects [mean age, 32.5 years, (range, 23-45 years)] who reported normal activities of daily living and underwent both T2-weighted axial images and MRE of thigh muscles on the same day. A sequence with a motion-encoding gradient was used in the MRE to map the propagating shear waves in the muscle. Elastic properties were quantified as the shear modulus of the following four thigh muscles at rest; the vastus medialis, vastus lateralis, adductor magnus, and biceps femoris. Results The mean shear modulus was 0.98 ± 0.32 kPa and 1.00 ± 0.33 kPa for the vastus medialis, 1.10 ± 0.46 kPa and 1.07 ± 0.43 kPa for the vastus lateralis, 0.91 ± 0.41 kPa and 0.93 ± 0.47 kPa for the adductor magnus, and 0.99 ± 0.37 kPa and 0.94 ± 0.32 kPa for the biceps femoris, with reader 1 and 2, respectively. No significant difference was observed in the shear modulus based on sex (p < 0.05). Aging consistently showed a statistically significant negative correlation (p < 0.05) with the shear modulus of the thigh muscles, except for the vastus medialis (p = 0.194 for reader 1 and p = 0.355 for reader 2). Conclusion MRE is a quantitative technique used to measure the elastic properties of individual muscles with excellent inter-observer agreement. Age was consistently significantly negatively correlated with the shear stiffness of muscles, except for the vastus medialis.

Semi-Quantitative Scoring of Late Gadolinium Enhancement of the Left Ventricle in Patients with Ischemic Cardiomyopathy: Improving Interobserver Reliability and Agreement Using Consensus Guidance from the Asian Society of Cardiovascular Imaging-Practical Tutorial (ASCI-PT) 2020

  • Cherry Kim;Chul Hwan Park;Do Yeon Kim;Jaehyung Cha;Bae Young Lee;Chan Ho Park;Eun-Ju Kang;Hyun Jung Koo;Kakuya Kitagawa;Min Jae Cha;Rungroj Krittayaphong;Sang Il Choi;Sanjaya Viswamitra;Sung Min Ko;Sung Mok Kim;Sung Ho Hwang;Nguyen Ngoc Trang;Whal Lee;Young Jin Kim;Jongmin Lee;Dong Hyun Yang
    • Korean Journal of Radiology
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    • v.23 no.3
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    • pp.298-307
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    • 2022
  • Objective: This study aimed to evaluate the effect of implementing the consensus statement from the Asian Society of Cardiovascular Imaging-Practical Tutorial 2020 (ASCI-PT 2020) on the reliability of cardiac MR with late gadolinium enhancement (CMR-LGE) myocardial viability scoring between observers in the context of ischemic cardiomyopathy. Materials and Methods: A total of 17 cardiovascular imaging experts from five different countries evaluated CMR obtained in 26 patients (male:female, 23:3; median age [interquartile range], 55.5 years [50-61.8]) with ischemic cardiomyopathy. For LGE scoring, based on the 17 segments, the extent of LGE in each segment was graded using a five-point scoring system ranging from 0 to 4 before and after exposure according to the consensus statement. All scoring was performed via web-based review. Scores for slices, vascular territories, and total scores were obtained as the sum of the relevant segmental scores. Interobserver reliability for segment scores was assessed using Fleiss' kappa, while the intraclass correlation coefficient (ICC) was used for slice score, vascular territory score, and total score. Inter-observer agreement was assessed using the limits of agreement from the mean (LoA). Results: Interobserver reliability (Fleiss' kappa) in each segment ranged 0.242-0.662 before the consensus and increased to 0.301-0.774 after the consensus. The interobserver reliability (ICC) for each slice, each vascular territory, and total score increased after the consensus (slice, 0.728-0.805 and 0.849-0.884; vascular territory, 0.756-0.902 and 0.852-0.941; total score, 0.847 and 0.913, before and after implementing the consensus statement, respectively. Interobserver agreement in scoring also improved with the implementation of the consensus for all slices, vascular territories, and total score. The LoA for the total score narrowed from ± 10.36 points to ± 7.12 points. Conclusion: The interobserver reliability and agreement for CMR-LGE scoring for ischemic cardiomyopathy improved when following guidance from the ASCI-PT 2020 consensus statement.