• Title/Summary/Keyword: Carbon Isotopes

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Monte Carlo Calculation for Production Cross-Sections of Projectile's Isotopes from Therapeutic Carbon and Helium Ion Beams in Different Materials

  • Quazi Muhammad Rashed Nizam;Asif Ahmed;Iftekhar Ahmed
    • Journal of Radiation Protection and Research
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    • v.48 no.4
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    • pp.204-212
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    • 2023
  • Background: Isotopes of the projectile may be produced along the beam path during the irradiation of a target by a heavy ion due to inelastic interactions with the media. This study analyzed the production cross-section of carbon (C) and Helium (He) projectile's isotopes resulting from the interactions of these beams with different materials along the beam path. Materials and Methods: In this study, we transport C and He ion beams through different materials. This transportation was made by the Monte Carlo simulation. Particle and Heavy Ion Transport code System (PHITS) has been used for this calculation. Results and Discussion: It has been found that 10C, 11C, and 13C from the 12C ion beam and 3He from the 4He ion beam are significant projectile's isotopes that have higher flux than other isotopes of these projectiles. The 4He ion beam has a higher projectile's isotope production cross-section along the beam path, which adds more impurities to the beam than the 12C ion beam. These projectile's isotopes from both the 12C and 4He ion beams have higher production cross-sections in hydrogenous materials like water or polyethylene. Conclusion: It is important to distinguish these projectile's isotopes from the primary beam particles to obtain a precise and accurate cross-section result by minimizing the error during measurement with a nuclear track detector. This study will show the trend of the production probability of projectile's isotopes for these ion beams.

Studies on Stream Ecosystem in the Bukhan River using Stable Isotopes (안정동위원소를 이용한 북한강 하천생태계 연구)

  • Kang, Jung-In;Kim, Jae-Gu;Lee, Sang-Don
    • Journal of Wetlands Research
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    • v.13 no.3
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    • pp.515-522
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    • 2011
  • This study examined the epiphytes using stable isotopes. Separated epiphytes should represent the water quality. In study areas, where agricultural paddies were prevailing, biomass of epiphytes can increase nitrogen isotopes(${\delta}^{15}N$) and as a result decrease in carbon isotopes(${\delta}^{13}C$). Naerin stream and Inbuk upper areas showed higher nitrogen isotopes(${\delta}^{15}N$) than in Hangye and Buk stream. Also, stable carbon isotopes(${\delta}^{13}C$) in Naerin stream and Inbuk streams tended to increase than in Hangye and Buk stream. This can indicate the epiphytes can be a good indicator for water quality pollution.

A STUDY ON THE SIMULTANEOUS MEASUREMENTS OF BETA EMITTING ISOTOPES

  • Lee, Goung-Jin;Kim, Seoung-Pyung
    • Journal of Radiation Protection and Research
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    • v.26 no.3
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    • pp.155-159
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    • 2001
  • Beta radiation is measured for an environmental monitoring purpose or for an internal radiation exposure monitoring of nuclear power plant's worker. In korea, strontium 89 and strontium 90 is measured for an environmental monitoring purpose. Also tritium and carbon 14 contained in urine is measured for an internal radiation exposure monitoring of nuclear power plant's worker. Because above isotopes emits low energy beta radiations having a wide range of energy, very complicated isotope separation preprocess is needed. In this study, two mixed beta emitting isotopes are measured simultaneously using a liquid scintillation counter(LSC) and analyzed by using a developed statistical method. Banded least square method is used to analyze the mixed spectrum, and the goodness-of-fitness test is proposed. Test results show that the developed procedure can be very useful for analyzing a mixed beta emitting isotopes.

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Palaeodietary Reconstruction of 6th Century Naju Yeongdong-ri People Recorded in Stable Carbon and Nitrogen Isotope Analysis of Human Bone Collagen (뼈 콜라겐의 탄소와 질소 안정동위원소에 기록된 6세기대 나주 영동리 고분군 피장자 집단의 식생활 양상)

  • Choe, Hyeon Goo;Shin, Ji Young
    • Journal of Conservation Science
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    • v.33 no.6
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    • pp.533-539
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    • 2017
  • Stable carbon and nitrogen isotope results recorded in human bone reflects palaeodiet, nutrition, subsistence and palaeoenvironment. We analyzed the remains of the Naju Yeongdong-ri people, who live at around $6^{th}$ century, excavated from stone chambers and stone-lined tombs. The following results of the analysis of stable carbon and nitrogen isotopes were obtained: ${\delta}^{13}C=-19.5{\pm}0.7$‰, ${\delta}^{15}N=9.6{\pm}0.7$‰, (n=9). The value for stable carbon isotopes indicates that the Naju Yeongdong-ri people had a largely $C_3$-based diet such as rice, barley, and beans. On the other hand, the value for stable nitrogen isotopes reflect the consumption of terrestrial animal protein. This study presents new information on the dietary patterns of the Naju Yeongdong-ri people, whose tombs were similar to the Baekje tomb style and their burial type was much like the one followed by the indigenous people of the Yeongsan river basin.

Food web structure in a $Salix$ $subfragilis$ dominated wetland in Hangang estuary using stable isotopes and fatty acid biomarkers

  • Han, Dong-Uk;Yang, Dong-Woo;Lee, Eun-Joo;Park, Sang-Kyu
    • Animal cells and systems
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    • v.16 no.2
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    • pp.162-171
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    • 2012
  • We investigated food webs of a $Salix$ $subfragilis$-dominated wetland in the Janghang wetland in the Hangang estuary, which is very close to the Demilitarized Zone, along the west coast of Korea. Our study focused on understanding sesarmine crab ($Sesarma$ $dehaani$)-related food webs in a $S.$ $subfragilis$ forest. For our study, we used carbon and nitrogen stable isotopes and fatty acid biomarkers. We collected samples of plants, animals, and detrital sediment from four quadrats ($5{\times}5m^2$) set in the $S.$ $subfragilis$ community. Samples were collected from September 2006 to June 2009, except during the winter hibernation period of $S.$ $dehaani$. In the wet season, the sediment showed relatively high ${\delta}^{13}C$ and low ${\delta}^{15}N$ signatures compared with relatively low ${\delta}13C$ and high ${\delta}15N$ signatures in the dry season. Mature $S.$ $dehaani$ appeared to feed on fresh leaves and other carbon sources, such as immature individuals or fish, in addition to detrital sediment, which appeared to be the main carbon source for immature crabs. Principal component analysis of fatty acid biomarkers of $S.$ $dehaani$ showed a clear difference between immature individuals (10-30 mm) and mature ones (larger than 30 mm), indicating that the main food source for immature crabs was detrital sediment, whereas mature crabs foraged plants in addition to consuming detrital sediment. On the basis of our results from stable isotope and fatty acid analyses, mature $S.$ $dehaani$ appeared to feed on detrital sediment and fresh leaves of $S.$ $subfragilis$ in summer in addition to engaging in cannibalism of immature individuals.

Stable C and N Isotopes: A Tool to Interpret Interacting Environmental Stresses on Soil and Plant

  • Yun, Seok-In;Ro, Hee-Myong
    • Journal of Applied Biological Chemistry
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    • v.51 no.6
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    • pp.262-271
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    • 2008
  • Natural abundances of stable isotopes of nitrogen and carbon (${\delta}^{15}N$ and ${\delta}^{13}C$) are being widely used to study N and C cycle processes in plant and soil systems. Variations in ${\delta}^{15}N$ of the soil and the plant reflect the potentially variable isotope signature of the external N sources and the isotope fractionation during the N cycle process. $N_2$ fixation and N fertilizer supply the nitrogen, whose ${\delta}^{15}N$ is close to 0%o, whereas the compost as. an organic input generally provides the nitrogen enriched in $^{15}N$ compared to the atmospheric $N_2$. The isotope fractionation during the N cycle process decreases the ${\delta}^{15}N$ of the substrate and increases the ${\delta}^{15}N$ of the product. N transformations such as N mineralization, nitrification, denitrification, assimilation, and the $NH_3$ volatilization have a specific isotope fractionation factor (${\alpha}$) for each N process. Variation in the ${\delta}^{13}C$ of plants reflects the photosynthetic type of plant, which affects the isotope fractionation during photosynthesis. The ${\delta}^{13}C$ of C3 plant is significantly lower than, whereas the ${\delta}^{13}C$ of C4 plant is similar to that of the atmospheric $CO_2$. Variation in the isotope fractionation of carbon and nitrogen can be observed under different environmental conditions. The effect of environmental factors on the stomatal conductance and the carboxylation rate affects the carbon isotope fractionation during photosynthesis. Changes in the environmental factors such as temperature and salt concentration affect the nitrogen isotope fractionation during the N cycle processes; however, the mechanism of variation in the nitrogen isotope fractionation has not been studied as much as that in the carbon isotope fractionation. Isotope fractionation factors of carbon and nitrogen could be the integrated factors for interpreting the effects of the environmental factors on plants and soils.

Characteristics of Nitrogen and Carbon Isotopes on Organic Matter and River Sediments of Toil Stream in Yeongju Dam Basin (영주댐 유역 토일천 유입 유기물 및 하천 퇴적물에 대한 질소와 탄소 동위원소 특성 연구)

  • Kang, Han;Song, Hye Won;Kim, Young Hun;Kim, Jeong Jin
    • Economic and Environmental Geology
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    • v.55 no.5
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    • pp.439-445
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    • 2022
  • Organic pollutants that contained in stream sediments have origins of mountain soil in natural and cattle manure in human activity. Nitrogen and carbon isotope analysis for mountain soil, cattle manure and stream sediment were performed for contribution evaluation of organic pollutants in Toil stream of Yeongju dam basin. Average carbon isotope ratio(δ13C) is -25.17‰, -22.34‰, and -26.39‰ for river sediments, cattle manure and mountain soil, respectively. Result of carbon isotope analysis suggests that river sediments are more affected by acid soils. Average value of the nitrogen isotope ratio (δ15N) is 9.46% for river sediment, 1.99% for mountain soil, and 19.53% for cattle manure. Result of nitrogen isotopic analysis show that contribution of cattle mature is slightly higher than that of mountain soil in Toil stream sediments.

Food-Web Structures in the Lower Trophic Levels of the Korean Seas (East Sea, West Sea, South Sea, and East China Sea) during the Summer Season: Using Carbon and Nitrogen Stable Isotopes (하계 한반도 해역(동해, 서해, 남해 및 동중국해)의 하위영양단계 먹이망 구조 : 탄소 및 질소 안정동위원소 활용)

  • Min, Jun-Oh;Lee, Chang-Hwa;Youn, Seok-Hyun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.26 no.5
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    • pp.493-505
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    • 2020
  • Food web structures in the lower trophic levels of the seas around the Korean peninsula were investigated in August 2019 using stable isotopes. There were variable ratios of the carbon (-26.18 ~ -20.61 ‰) and nitrogen stable (5.36 ~ 15.20 ‰) isotopes in the particulate organic matter (POM). Most of the organisms ingested micro-POM as a major food source, but this varied spatially. The chaetognaths (3.40 ± 0.61) occupied the highest trophic level. The isotope mixing model showed that the proportions (13 ~ 51 %) of some organisms (i.e., copepods and euphausiids) reflected the relative contributions as major food sources for chaetognaths at each site.

Paleovegetation and Paleoclimate Changes in Southeastern Part of the Korean Peninsula over the Last 30 kyr Inferred from Plant Wax Carbon Isotopes (장족형 탄화수소(n-alkane)의 탄소 안정동위원소비를 통한 과거 3만년 동안 한반도 남동해안의 고식생 및 고기후 복원)

  • Suh, Yeon Jee;Hyun, Sangmin
    • Ocean and Polar Research
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    • v.40 no.4
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    • pp.289-297
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    • 2018
  • This study reconstructs past vegetation changes in southeastern Korea over the last 30 thousand years using plant waxes (i.e. long chain n-alkanes) and their carbon isotopic compositions (${\delta}^{13}C_{alk}$) preserved in marine sediment core (KIODP 12-1) retrieved from the East Sea. Here we show changes in vegetation composition in the Korean peninsula in relation to the strength of the East Asian Summer Monsoon. During the Last Glacial Maximum (LGM), when the summer monsoon weakened, precipitation decreased and $C_3$ grassland expanded. After the LGM, the summer monsoon gradually intensified, increasing rainfall, and thus expanding the forestland coverage. Precipitation climaxed from 10 to 6 kyr BP, which includes the Holocene Climate Optimum. The grassland began to expand since 5 kyr BP due to climate warming and drying towards the present. The ${\delta}^{13}C_{alk}$ values may also have been influenced by agricultural activities, which is known to have begun since the late Neolithic (ca. 7.0~3.0 kyr BP). Our results demonstrate how changes in the global climate state influence regional atmospheric circulation and precipitation distribution, and consequently terrestrial plant composition in southeastern Korea.

Comparison of Morphological Characters and Stable Isotopes of Seeds between Wild Simulated Ginseng and Cultivated Field Ginseng (국내 산양삼과 인삼 종자의 형태적 형질과 안정성 동위원소 비교)

  • Choi, Myoung Sub;Kim, Sunhee;Park, Chan Ryul;Kim, Namyoung;Shin, Jinsub
    • Journal of Korean Society of Forest Science
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    • v.97 no.4
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    • pp.357-362
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    • 2008
  • We compared the morphological characters and stable isotopes of seeds of wild simulated ginseng with those of cultivated field ginseng. Seeds were collected from ten areas for wild simulated ginseng and two areas for cultivated field ginseng. The length, width, thickness and number of seeds per gram were measured and the ratio of stable isotopes of carbon and nitrogen was analysed as well. There was a overlapping variation of morphological characters and the ratio of stable isotope of the wild simulated ginseng among study areas. In Geumsan area, compared with the seed of cultivated field ginseng, the seed of wild simulated ginseng was significantly small and light, and the ${\delta}^{15}N$(‰) of wild simulated ginseng was lower than that of cultivated field ginseng. However, it is somewhat impossible to compare the regional variation of the unique value of ${\delta}^{15}N$(‰) among study areas of wild simulated ginseng. We can suggest the value of ${\delta}^{15}N$(‰) can be used as detection factor for cultivation regime like chemical fertilization and organic farming.