Academic literature on the topic 'Exhalation rate'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Exhalation rate.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Exhalation rate"
1
Döse, Magnus, and Johan Silfwerbrand. "Effect on Radon Exhalation Rate Due to Cracks in Concrete." Nordic Concrete Research 61, no. 2 (2019): 79–90. http://dx.doi.org/10.2478/ncr-2019-0018.
Full textAbstract:
Abstract The second largest cause of lung cancer in the World is related to radon (222Rn) and its progenies in our environment. Building materials, such as concrete, contribute to the production of radon gas through the natural decay of 238U from its constituents. The Swedish Cement and Concrete Research Institute (CBI), part of RISE (Research Institute of Sweden AB), has examined the effects of cracks in concrete on two different concrete recipes where an Ordinary Portland Cement, OPC-CEM-I concrete (REF) and an OPC concrete including a hydrophobic additive (ADD) were addressed. Two concrete prisms from each concrete recipe were examined. The radon exhalation rate was measured in the pristine state and after concrete cracks had been induced into the concrete prisms. Measurements were performed with an ATMOS 33 ionizing pulsation chamber. The results indicate a strong influence of cracks on the radon exhalation rate. An increase in radon exhalation rate was calculated for every test prism. The increase in radon exhalation rate varied between 80 and 260 %. The crack apertures may play a significant role on the exhalation rate. The concrete prisms with the largest apertures (ADD) also generated the highest radon exhalation rates. The results imply that there could be a substantial variation in the exhalation rate, due to numerous factors, but nonetheless, the results should, raise the awareness of the impact cracks in concrete structures, may have on the final exhalation rate of radon. The exhalation rate of the recipe with an additive (ADD) also showed a lower exhalation rate than for the reference recipe (REF), when compared in a pristine state. This was in part expected. However, the effect of induced cracks and its aperture, seemingly trumps the effect that an additive may play on the radon exhalation rate, when cracks are induced. The hypothesis is in part verified in view of the results of the prism for the ordinary Portland recipe (REF-prisms), were an increase of approximately 100 % would be expected due to the total surface increase. The results also indicate this. The major increase in the radon exhalation rate of the ordinary Portland recipe including an additive, implies however other factors, such as minor internal cracks, that may substantially contribute to the final exhalation rate.
2
Nikolic, Mladen, and Rodoljub Simovic. "Radon exhalation rates of some granites used in Serbia." Nuclear Technology and Radiation Protection 30, no. 2 (2015): 145–48. http://dx.doi.org/10.2298/ntrp1502145n.
Full textAbstract:
In order to address concern about radon exhalation in building material, radon exhalation rate was determined for different granites available on Serbian market. Radon exhalation rate, along with mass exhalation rate and effective radium content were determined by closed chamber method and active continuous radon measurement technique. For this research, special chambers were made and tested for back diffusion and leakage, and the radon concentrations measured were included in the calculation of radon exhalation. The radon exhalation rate ranged from 0.161 Bq/m2h to 0.576 Bq/m2h, the mass exhalation rate from 0.167 Bq/kgh to 0.678 Bq/kgh, while the effective radium content was found to be from 12.37 Bq/kg to 50.23 Bq/kg. The results indicate that the granites used in Serbia have a low level of radon exhalation.
3
Jabbade, Meryame, Abdellatif Nachab, Elmokhtar Elouardi, et al. "Study of the effect of temperature and water content on radon exhalation from phosphate using LR-115 detectors." Radiation Protection Dosimetry 199, no. 18 (2023): 2212–17. http://dx.doi.org/10.1093/rpd/ncad172.
Full textAbstract:
Abstract A study of the influence of moisture content on the radon exhalation rate from phosphate samples (with and without consideration of the back diffusion effect) was performed using the sealed cup technique. The mass exhalation rate was found to increase with an increase in moisture content, reaching a maximum value of 2.414 ± 0.034 Bq kg−1 h−1 with a moisture content of 10%. However, the mass exhalation rate decreased with a continued increase in moisture content above 25%. The mass exhalation rate was also measured at different temperatures between −10 and 50°C. The obtained results show that the mass exhalation rate increases linearly with temperature. We point out that all the obtained values of radon exhalation rate are lower than the world average radon exhalation rate (57.6 Bq m−2 h−1).
4
Lin, F., R. Xie, Z. Fan, et al. "Comparison of two models for measuring radon exhalation rate with a ventilation chamber by numerical simulation." Journal of Instrumentation 17, no. 10 (2022): P10007. http://dx.doi.org/10.1088/1748-0221/17/10/p10007.
Full textAbstract:
Abstract Two models can be used to measure the radon exhalation rate with a ventilation chamber. The first is the custom model with a flow meter, and the second is the improved model without flow meter. As the established radon exhalation standard facilities can't simulate any medium to be measured by adjusting the radon exhalation rate and effective decay constants as required, numerical simulation is useful to compare the two models for measuring radon exhalation rate under different effective decay constants. Three different effective decay constants and two different radon exhalation rates were simulated for measuring radon exhalation rates, and the simulation results confirmed that the improved model is quick and accurate even when the radon exhalation rate is very low. While the custom model can only be used to calculate the radon exhalation rates when the ventilation rate is far larger than the effective decay constant, and it takes a long time for the radon concentration inside the ventilation chamber to be stable. Therefore, the improved model without flow meter is more accurate to measure the radon exhalation rate under different effective decay constants.
5
Kozłowska, Beata, Jadwiga Mazur, Krzysztof Kozak, Agata Walencik-Łata, and Błażej Baic. "Investigation of the influence of chamber construction parameters on radon exhalation rate." Nukleonika 61, no. 3 (2016): 269–73. http://dx.doi.org/10.1515/nuka-2016-0045.
Full textAbstract:
Abstract Radon exhalation from ground is a process dependent on the emanation and migration of radon through ambient air. Most studies on radon exhalation from soil were performed regarding the influence of meteorological and soil parameters. As radon exhalation rate can be affected by the internal properties of the sample, it may also be influenced by the exhalation chamber geometry such as volume-to-area (V/S) ratio or other construction parameters. The measurements of radon exhalation from soil were made using different constructions of accumulation chamber and two types of radon monitors: RAD7 (Durridge) and AlphaGUARD PQ2000PRO (Genitron). The measurements were performed on one site in two locations and approximately at the same time. The first tests did not show the correlations of exhalation rate values and the chamber’s construction parameters and their geometrical dimensions. However, when examining the results, it seems that there are still too many factors that might have affected the process of radon exhalation. The future experiments are planned to be conducted in controlled laboratory conditions.
6
Li, Huiying, Zhongkai Fan, Shuaibin Liu, et al. "A novel method to simulate radon exhalation rate with a solid Rn-222 source." Journal of Instrumentation 19, no. 07 (2024): T07006. http://dx.doi.org/10.1088/1748-0221/19/07/t07006.
Full textAbstract:
Abstract Radon exhaled from rocks, building materials, and soil can be harmful to human health, so it is necessary to measure radon and its exhalation rate. In this paper, a novel method is proposed to simulate radon exhalation from different medium surface by using a solid Rn-222 source, and the radon exhalation rate can be adjusted by replacing radon accumulation chambers with different bottom areas. Firstly, an experiment was done to determine the activity of the Rn-222 source, and then the theoretical radon exhalation rate can be quickly calculated from the relationship between the radon source activity and the bottom area of the radon accumulation chamber. Three sets of comparative experiments were conducted using two radon accumulation chambers with different volumes, respectively. Comparing the average values obtained from the experiments with the calculated theoretical values, it can be obtained that the differences corresponding to the two radon accumulation chambers between the theoretical radon exhalation rates and the experimentally average values are all within 6%. Without replacing the radon source, the radon exhalation rate is inversely varies with the bottom area of the chamber. Therefore, the correctness of adjusting the radon exhalation rate by replacing radon accumulation chambers with different bottom areas to simulate radon exhalation from different media surfaces is verified. This method can be used to calibrate the radon exhalation measuring instruments.
7
Kaliprasad, CS, PR Vinutha, and Y. Narayana. "Natural Radionuclides and Radon Exhalation Rate in the Soils of Cauvery River Basin." Air, Soil and Water Research 10 (January 1, 2017): 117862211774694. http://dx.doi.org/10.1177/1178622117746948.
Full textAbstract:
In this study, systematic measurement of activity concentrations of 40K, 226Ra, and 232Th and radon exhalation rate has been done in soil samples of Cauvery River environment. The activity was measured using HPGe gamma-ray spectrometer, and the mean values of 40K, 226Ra, and 232Th in the soil samples were found to be 182 ± 4, 34 ± 2, and 19 ± 1 Bq kg−1, respectively. The radon exhalation rate was measured by “Can technique” using SSNTD (LR-115) films. The mean values of radium concentration, surface exhalation, and mass exhalation rate were found to be 118.95, 293.61, and 108.53 mBq kg−1 h−1, respectively. The radiological hazard indices due to natural radioactivity were calculated and compared with international recommended values, which are lower than the recommended level. The radon exhalation rate is lower than the recommended level.
8
Ambrosino, Fabrizio, Giuseppe La Verde, Gaetano Gagliardo, et al. "Radon Exhalation Rate: A Metrological Approach for Radiation Protection." Sensors 24, no. 11 (2024): 3633. http://dx.doi.org/10.3390/s24113633.
Full textAbstract:
Radon, a radioactive inert gas that comes from the decay of naturally occurring radioactive species, poses a substantial health risk due to its involvement in lung cancer carcinogenesis. This work proposes a metrological approach for determining radon exhalation rates from diverse building materials. This methodology employs an electrostatic collection chamber for alpha spectrometry of radon isotopic decay products. Experimental evaluations were conducted particularly focusing on volcanic gray tuff from Sant’Agata de’ Goti (Campania region, Italy), a material commonly utilized in construction, to assess radon exhalation rates. The study aligns with Legislative Decree 101/2020, a transposition of European Directive 59/2013/Euratom, highlighting the need to identify materials with a high risk of radon exhalation. Moreover, this work supports the goals of the Italian National Radon Action Plan related to the aforementioned decree, aiming to develop methodologies for estimating radon exhalation rates from building materials and improving radioprotection practices.
9
Ye, Yongjun, Wenhao Wu, Chunhua Huang, and Kimberlee J. Kearfott. "Experimental study of the effect of seepage on radon exhalation in circular tubular porous emanation media." Indoor and Built Environment 29, no. 5 (2019): 701–10. http://dx.doi.org/10.1177/1420326x19861781.
Full textAbstract:
Radium, which is naturally present in many rocks, decays to the radioactive gas radon, which is then exhaled from the surface of underground tunnels and other underground buildings and is a major source of human exposure to radioactivity. A mathematical model for the migration of radon from a circular tubular emanation medium was established based on the seepage–diffusion migration theory for radon in porous emanation media, such as artificial retaining walls and the surrounding rocks in these locations. An analytical solution for the distribution of radon concentrations and the calculation formula for the radon exhalation rate under steady-state conditions were then obtained. An experimental device was designed to determine the radon exhalation rate under different pressure gradients. The theoretical calculation values for the radon exhalation rate and the total amount of radon exhalation are in good agreement with the experimental results. The radon exhalation rate at the low-pressure side increases with an increase in seepage velocity (pressure difference), while the radon exhalation rate at the high-pressure side is on the contrary. The total amount of radon exhalation increased over time with an increase in the seepage velocity and tended towards a maximum value.
10
Chitra, N., S. Bala Sundar, V. Subramanian, M. T. Jose, R. Baskaran, and B. Venkatraman. "QUANTIFICATION OF BACK DIFFUSION IN RADON AND THORON EXHALATION RATE MEASUREMENTS." Radiation Protection Dosimetry 189, no. 2 (2020): 182–89. http://dx.doi.org/10.1093/rpd/ncaa029.
Full textAbstract:
Abstract The radon (222Rn) and thoron (220Rn) fluxes from the soil and building materials are the major contributors to their indoor levels. Hence, the measurement of radon and thoron exhalation rates from the source matrix becomes the foremost step in controlling the indoor radon and thoron exposure. It is a challenge to measure the exhalation rates without disturbing the natural conditions. The back-diffusion phenomenon modifies the exhalation rate. The work presented here is to measure the back-diffusion coefficient and takes it into consideration while estimating the exhalation rate. For radon measurements, the back-diffusion coefficient and the free exhalation rates were simultaneously estimated by adopting a novel methodology. The leak rate of the experimental setup measured by this methodology was agreeable with the value measured by adopting the standard technique. In the case of thoron, the back-diffusion effect was found to be negligible for the present experimental conditions and it is duly explained. The above results were obtained by analyzing two soil samples with high 238U and 232Th content collected from monazite-rich coastal area.
Dissertations / Theses on the topic "Exhalation rate"
1
Goto, Masayoshi, Jun Moriizumi, Hiromi Yamazawa, Takao lida, and Weihai Zhuo. "Estimation of global radon exhalation rate distribution." American Institite of Physics, 2008. http://hdl.handle.net/2237/12041.
Full text
2
Salim, Leonardo Alfredo [UNESP]. "Radônio em área de extração de carvão mineral no município de Figueira (PR)." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/154384.
Full textAbstract:
Submitted by LEONARDO ALFREDO SALIM null (leonardosalim_las@hotmail.com) on 2018-06-27T16:08:53Z
No. of bitstreams: 1
Tese Leonardo Alfredo Salim.pdf: 12084411 bytes, checksum: 4e4df6683eab7d6125b71ecc8e629d94 (MD5)<br>Approved for entry into archive by Adriana Aparecida Puerta null (dripuerta@rc.unesp.br) on 2018-06-28T12:11:24Z (GMT) No. of bitstreams: 1
salim_la_me_rcla.pdf: 11907717 bytes, checksum: 326a51071a02d7874baae0361ba36f01 (MD5)<br>Made available in DSpace on 2018-06-28T12:11:24Z (GMT). No. of bitstreams: 1
salim_la_me_rcla.pdf: 11907717 bytes, checksum: 326a51071a02d7874baae0361ba36f01 (MD5)
Previous issue date: 2018-05-02<br>Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)<br>O gás radônio, resultado do decaimento radioativo do 238U e 232Th, é motivo de grande preocupação para o homem. Ele é uma das mais importantes fontes de radiação ionizante de origem natural que as pessoas estão expostas, sendo considerado pela OMS (Organização Mundial da Saúde) como o segundo maior causador de câncer de pulmão. O carvão mineral como qualquer outro combustível fóssil está associado a materiais radioativos naturais, devido principalmente ao seu conteúdo de 238U e 232Th. Para a compreensão do comportamento do gás radônio em área de mineração de carvão e determinar o grau de exposição das pessoas ao gás nesta área, foram determinadas a taxa de exalação de radônio de amostras de carvão, cinza, siltito e tufo vulcânico coletadas na mina Amado Simões PI-08 (Companhia Carbonífera do Cambuí), em Figueira (PR), a concentração de radônio no ar do interior da mina e a concentração de radônio, parâmetros físicos e químicos dos solos próximos à mina. As taxas de exalações foram obtidas por curvas experimentais da concentração de radônio em função do tempo, e variaram de 0,064 a 0,717 Bq/kg.h. Observou-se que o gás radônio entrou em equilíbrio radioativo após 180 horas de análise. A concentrações de radônio dissolvido no ar do interior da mina variaram de 7,2 a 770,5 Bq/m³, observou-se que o radônio tem maior escape das rochas por fraturas presentes nas frentes de lavra e que maior taxa de exalação vem das rochas encaixantes, remetendo em um problema radiológico à área de descarte. A concentrações de radônio nas amostras de solo variaram de 0,04 a 276,48 (kBq/m³), a qual obteve correlação com a concentração de U, que variou de 0,43 a 8,46 ppm. Observou-se a tendência do radônio se acumular em ambientes com maior concentração de urânio, úmidos, aluminosos, argilosos e com presença de matéria orgânica.<br>Radon gas, the result of the radioactive decay of 238U and 232Th, is a matter of great concern to man. It is one of the most important sources of naturally occurring ionizing radiation that people are exposed to and is considered by the World Health Organization (WHO) to be the second largest cause of lung cancer. Mineral coal like any other fossil fuel is associated with natural radioactive materials, mainly due to its content of 238U and 232Th. In order to understand the behavior of the radon gas in the coal mining area and determine the degree of exposure of the people to the gas in this area, the radon exhalation rate of samples of coal, ash, silt, and volcanic tuff collected at the Amado mine Simões PI-08 (Companhia Carbonífera do Cambuí), in Figueira (PR), the radon concentration in the air inside the mine and the radon concentration, physical and chemical parameters of the soils near the mine. The exhalation rates were obtained by experimental curves of the radon concentration as a function of time, and ranged from 0.064 to 0.717 Bq / kg.h. It was observed that the radon gas entered into radioactive equilibrium after 180 hours of analysis. The concentrations of radon dissolved in the air inside the mine varied from 7.2 to 770.5 Bq / m³, it was observed that the radon has greater escape of the rocks by fractures present in the mining fronts and that higher exhalation rate comes from encasing rocks, sending in a radiological problem to the area of discard. The concentrations of radon in the soil samples ranged from 0.04 to 276.48 (kBq / m³), which correlated with the U concentration, which ranged from 0.43 to 8.46 ppm. It was observed the tendency of radon to accumulate in environments with higher concentration of uranium, humid, aluminous, clayey and with presence of organic matter.<br>CNPq: 142378/2017-8.
3
Lawrence, Cameron Eoin. "Measurement of 222Rn Exhalation Rates and 210Pb Deposition Rates in a Tropical Environment." Thesis, Queensland University of Technology, 2006. https://eprints.qut.edu.au/16291/1/Cameron_Lawrence_Thesis.pdf.
Full textAbstract:
This thesis provides the measurements of 222Rn exhalation rates, 210Pb deposition rates and excess 210Pb inventories for locations in and around Ranger Uranium Mine and Jabiru located within Kakadu National Park, Australia. Radon-222 is part of the natural 238U series decay chain and the only gas to be found in the series under normal conditions. Part of the natural redistribution of 222Rn in the environment is a portion exhales from the ground and disperses into the atmosphere. Here it decays via a series of short-lived progeny, that attach themselves to aerosol particles, to the long lived isotope 210Pb (T1/2 = 22.3 y). Attached and unattached 210Pb is removed from the atmosphere through wet and dry deposition and deposited on the surface of the earth, the fraction deposited on soils is gradually transported through the soil and can create a depth profile of 210Pb. Here it decays to the stable isotope 206Pb completing the 238U series.
Measurements of 222Rn exhalation rates and 210Pb deposition rates were performed over complete seasonal cycles, August 2002 - July 2003 and May 2003 - May 2004 respectively. The area is categorised as wet and dry tropics and it experiences two distinct seasonal patterns, a dry season (May-October) with little or no precipitation events and a wet season (December-March) with almost daily precipitation and monsoonal troughs. November and April are regarded as transitional months. As the natural processes of 222Rn exhalation and 210Pb deposition are heavily influenced by soil moisture and precipitation respectively, seasonal variations in the exhalation and deposition rates were expected. It was observed that 222Rn exhalation rates decreased throughout the wet season when the increase in soil moisture retarded exhalation. Lead-210 deposition peaked throughout the wet season as precipitation is the major scavenging process of this isotope from the atmosphere.
Radon-222 is influenced by other parameters such as 226Ra activity concentration and distribution, soil porosity and grain size. With the removal of the influence of soil moisture during the dry season it was possible to examine the effect of these other variables in a more comprehensive manner. This resulted in categorisation of geomorphic landscapes from which the 222Rn exhalation rate to 226Ra activity concentration ratios were similar during the dry season. These results can be extended to estimate dry season 222Rn exhalation rates from tropical locations from a measurement of 226Ra activity concentration.
Through modelling the 210Pb budget on local and regional scales it was observed that there is a net loss of 210Pb from the region, the majority of which occurs during the dry season. This has been attributed to the fact that 210Pb attached to aerosols is transported great distance with the prevailing trade winds created by a Hadley Circulation cell predominant during the dry season (winter) months. By including the influence of factors such as water inundation and natural 210Pb redistribution in the soil wet season budgeting of 210Pb on local and regional scales gave very good results.
4
Lawrence, Cameron Eoin. "Measurement of 222Rn Exhalation Rates and 210Pb Deposition Rates in a Tropical Environment." Queensland University of Technology, 2006. http://eprints.qut.edu.au/16291/.
Full textAbstract:
This thesis provides the measurements of 222Rn exhalation rates, 210Pb deposition rates and excess 210Pb inventories for locations in and around Ranger Uranium Mine and Jabiru located within Kakadu National Park, Australia. Radon-222 is part of the natural 238U series decay chain and the only gas to be found in the series under normal conditions. Part of the natural redistribution of 222Rn in the environment is a portion exhales from the ground and disperses into the atmosphere. Here it decays via a series of short-lived progeny, that attach themselves to aerosol particles, to the long lived isotope 210Pb (T1/2 = 22.3 y). Attached and unattached 210Pb is removed from the atmosphere through wet and dry deposition and deposited on the surface of the earth, the fraction deposited on soils is gradually transported through the soil and can create a depth profile of 210Pb. Here it decays to the stable isotope 206Pb completing the 238U series. Measurements of 222Rn exhalation rates and 210Pb deposition rates were performed over complete seasonal cycles, August 2002 - July 2003 and May 2003 - May 2004 respectively. The area is categorised as wet and dry tropics and it experiences two distinct seasonal patterns, a dry season (May-October) with little or no precipitation events and a wet season (December-March) with almost daily precipitation and monsoonal troughs. November and April are regarded as transitional months. As the natural processes of 222Rn exhalation and 210Pb deposition are heavily influenced by soil moisture and precipitation respectively, seasonal variations in the exhalation and deposition rates were expected. It was observed that 222Rn exhalation rates decreased throughout the wet season when the increase in soil moisture retarded exhalation. Lead-210 deposition peaked throughout the wet season as precipitation is the major scavenging process of this isotope from the atmosphere. Radon-222 is influenced by other parameters such as 226Ra activity concentration and distribution, soil porosity and grain size. With the removal of the influence of soil moisture during the dry season it was possible to examine the effect of these other variables in a more comprehensive manner. This resulted in categorisation of geomorphic landscapes from which the 222Rn exhalation rate to 226Ra activity concentration ratios were similar during the dry season. These results can be extended to estimate dry season 222Rn exhalation rates from tropical locations from a measurement of 226Ra activity concentration. Through modelling the 210Pb budget on local and regional scales it was observed that there is a net loss of 210Pb from the region, the majority of which occurs during the dry season. This has been attributed to the fact that 210Pb attached to aerosols is transported great distance with the prevailing trade winds created by a Hadley Circulation cell predominant during the dry season (winter) months. By including the influence of factors such as water inundation and natural 210Pb redistribution in the soil wet season budgeting of 210Pb on local and regional scales gave very good results.
5
Al-Farsi, Afkar Nadhim. "Radiological aspects of petroleum exploration and production in the sultanate of Oman." Thesis, Queensland University of Technology, 2008. https://eprints.qut.edu.au/29817/1/Afkar_Al-Farsi_Thesis.pdf.
Full textAbstract:
This thesis is a study of naturally occurring radioactive materials (NORM) activity concentration, gamma dose rate and radon (222Rn) exhalation from the waste streams of large-scale onshore petroleum operations. Types of activities covered included; sludge recovery from separation tanks, sludge farming, NORM storage, scaling in oil tubulars, scaling in gas production and sedimentation in produced water evaporation ponds. Field work was conducted in the arid desert terrain of an operational oil exploration and production region in the Sultanate of Oman.
The main radionuclides found were 226Ra and 210Pb (238U - series), 228Ra and 228Th (232Th - series), and 227Ac (235U - series), along with 40K. All activity concentrations were higher than the ambient soil level and varied over several orders of magnitude. The range of gamma dose rates at a 1 m height above ground for the farm treated sludge had a range of 0.06 0.43 µSv h 1, and an average close to the ambient soil mean of 0.086 ± 0.014 µSv h 1, whereas the untreated sludge gamma dose rates had a range of 0.07 1.78 µSv h 1, and a mean of 0.456 ± 0.303 µSv h 1. The geometric mean of ambient soil 222Rn exhalation rate for area surrounding the sludge was mBq m 2 s 1. Radon exhalation rates reported in oil waste products were all higher than the ambient soil value and varied over three orders of magnitude.
This study resulted in some unique findings including: (i) detection of radiotoxic 227Ac in the oil scales and sludge, (ii) need of a new empirical relation between petroleum sludge activity concentrations and gamma dose rates, and (iii) assessment of exhalation of 222Rn from oil sludge. Additionally the study investigated a method to determine oil scale and sludge age by the use of inherent behaviour of radionuclides as 228Ra:226Ra and 228Th:228Ra activity ratios.
6
Al-Farsi, Afkar Nadhim. "Radiological aspects of petroleum exploration and production in the sultanate of Oman." Queensland University of Technology, 2008. http://eprints.qut.edu.au/29817/.
Full textAbstract:
This thesis is a study of naturally occurring radioactive materials (NORM) activity concentration, gamma dose rate and radon (222Rn) exhalation from the waste streams of large-scale onshore petroleum operations. Types of activities covered included; sludge recovery from separation tanks, sludge farming, NORM storage, scaling in oil tubulars, scaling in gas production and sedimentation in produced water evaporation ponds. Field work was conducted in the arid desert terrain of an operational oil exploration and production region in the Sultanate of Oman.
The main radionuclides found were 226Ra and 210Pb (238U - series), 228Ra and 228Th (232Th - series), and 227Ac (235U - series), along with 40K. All activity concentrations were higher than the ambient soil level and varied over several orders of magnitude. The range of gamma dose rates at a 1 m height above ground for the farm treated sludge had a range of 0.06 0.43 µSv h 1, and an average close to the ambient soil mean of 0.086 ± 0.014 µSv h 1, whereas the untreated sludge gamma dose rates had a range of 0.07 1.78 µSv h 1, and a mean of 0.456 ± 0.303 µSv h 1. The geometric mean of ambient soil 222Rn exhalation rate for area surrounding the sludge was mBq m 2 s 1. Radon exhalation rates reported in oil waste products were all higher than the ambient soil value and varied over three orders of magnitude.
This study resulted in some unique findings including: (i) detection of radiotoxic 227Ac in the oil scales and sludge, (ii) need of a new empirical relation between petroleum sludge activity concentrations and gamma dose rates, and (iii) assessment of exhalation of 222Rn from oil sludge. Additionally the study investigated a method to determine oil scale and sludge age by the use of inherent behaviour of radionuclides as 228Ra:226Ra and 228Th:228Ra activity ratios.
7
Lee, Jia-Sheng, and 李家聲. "A Study on the Exhalation Rate of Radon and Thoron by Alpha-Spectrum Method." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/02818426997911606351.
Full text
8
Sannappa, J. "Study of radon exhalation rate and concentrations of randon in indoor and outdoor atmospheres at Mysore." Thesis, 1999. http://hdl.handle.net/2009/2764.
Full textBooks on the topic "Exhalation rate"
1
Kreit, John W. Dynamic Hyperinflation and Intrinsic Positive End-Expiratory Pressure. Edited by John W. Kreit. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190670085.003.0010.
Full textAbstract:
Dynamic hyperinflation and intrinsic PEEP almost always occur in patients with severe obstructive lung disease, in whom slowing of expiratory flow prevents complete exhalation. Occasionally, patients without airflow obstruction develop dynamic hyperinflation when expiratory time, is excessively shortened by a rapid respiratory rate, a long set inspiratory time (TI), or both. Dynamic Hyperinflation and Intrinsic Positive End-Expiratory Pressure describes the causes of dynamic hyperinflation and the mechanisms of its adverse effects, including reduced cardiac output and blood pressure, pulmonary barotrauma, and ineffective ventilator triggering. The chapter also describes how to screen for and measure intrinsic PEEP, and how to reduce or eliminate its adverse effects.
2
Aguirre-Bermeo, Hérnan, and Jordi Mancebo. Pressure support ventilation. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0097.
Full textAbstract:
Pressure support ventilation (PSV) is one of the most common ventilatory modalities used in intensive care units. PSV is an assisted, pressure-limited, and flow-cycled ventilatory mode. The ventilator provides assistance when the patient makes a breathing effort, and when inspiratory flow reaches a certain threshold level, cycling to exhalation occurs. PSV unloads respiratory muscle effort, while allowing the patient to retain control over the respiratory rate and tidal volume. Withdrawal from mechanical ventilation should be performed with a gradual reduction of levels of support until extubation. Asynchronies can be present during PSV and are typically associated with high levels of support. A closed-loop modality, which adjusts support levels to keep the patient in a ‘comfort zone’, has been designed to assist in the withdrawal of mechanical ventilation. It performs at least as well as experienced medical staff and could be useful in specific groups of patients.
3
Radon exhalative properties, radioelement content and rare earth element composition of Namurian phosphorite deposits, Co. Clare. Geological Survey of Ireland, 1994.
Find full textBook chapters on the topic "Exhalation rate"
1
Eskelson, C. D., M. Chvapil, J. Szebeni, and I. G. Sipes. "Effects of Ultraviolet Light Irradiation, Carbon Tetrachloride, and Trichloroethylene on Ethane Exhalation in Rats." In Prostaglandin and Lipid Metabolism in Radiation Injury. Springer US, 1987. http://dx.doi.org/10.1007/978-1-4684-5457-4_41.
Full text
2
Schmezer, P., B. M. Schmezer, B. L. Pool-Zobel, and R. G. Klein. "Studies on the exhalation of volatile N-Nitrosamines following systemic application to Sprague-Dawley rats." In Environmental Hygiene III. Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-642-77112-5_31.
Full text
3
Cosma, C., O. Cozar, T. Jurcut, C. Baciu, and I. Pop. "Simultaneous measurement of radon and thoron exhalation rate from soil and building materials." In Radioactivity in the Environment. Elsevier, 2005. http://dx.doi.org/10.1016/s1569-4860(04)07086-x.
Full text
4
Farhan Nader Alrekabi, Ali. "Mathematical Expressions of Radon Measurements." In Recent Techniques and Applications in Ionizing Radiation Research. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.92647.
Full textAbstract:
The measurement of radon, thoron and their progeny concentrations also leads to the knowledge of the presence of radioactive elements, which are the sources of these elements such as Uranium-238 and Thorium-232. Using of Solid State Nuclear Tracks Detectors (SSNTDs) it is probably the most widely applied for long term radon measurements. In this chapter, we derived the most important mathematical relationships that researchers need in radon measurements to calculate such as average radon concentration, exhalation rate, equilibrium factor, radon diffusion coefficient and transmission factor to get actual radon concentration in air atmosphere. The relationship between theoretical and experiment calibration drive and other mathematical relationships are given in this chapter.
5
Roelofs, L., R. Wiegers, K. H. Puch, and G. Keller. "EU-Concerted Action for a survey on radon exhalation rate measurements for building materials and soils." In Radioactivity in the Environment. Elsevier, 2005. http://dx.doi.org/10.1016/s1569-4860(04)07061-5.
Full text
6
Roberts, Charlotte A. "The Biology of Leprosy Bacteria and How they are Transmitted to Humans." In Leprosy. University Press of Florida, 2020. http://dx.doi.org/10.5744/florida/9781683401841.003.0002.
Full textAbstract:
This chapter considers the nature of the bacterial causes of leprosy, Mycobacterium leprae and Mycobacterium lepromatosis, including research on their genomes. Paucibacillary leprosy is the high-resistance form of leprosy and multibacillary leprosy is the low-resistance form. It is clear that genomic research, including the documentation of different strains of the bacterium and identifying susceptibility and resistance genes, is providing knowledge that is helping to track transmission and identify areas within regions of countries that remain challenges for management. While it is concluded that leprosy is transmitted through the exhalation and then inhalation of bacteria-laden droplets (droplet infection), other reported mechanisms have been discussed, and there are environmental sources of the bacteria. Leprosy in children is rare, and males are affected more than females. The wide range of intrinsic (e.g., age, sex) and extrinsic (e.g., diet, living conditions) factors that make people more or less susceptible to leprosy provide a complex picture to manage when thinking about why any particular person contracts the infection. The wild nine-banded armadillo and the red squirrel natural endemic hosts for M. leprae, but while non-human primates may be affected there is no evidence of them being infected in the wild.
7
Slack, John F., Terry W. Offield, Laurel G. Woodruff, and Wayne C. Shanks. "Geology and Geochemistry of Besshi-Type Massive Sulfide Deposits of the Vermont Copper Belt." In Part I. Proterozoic Iron and Zinc Deposits of the Adirondack Mountains of New York and the New Jersey Highlands Part II. Environmental Geochemistry and Mining History of Massive Sulfide Deposits in the Vermont Copper Belt. Society of Economic Geologists, 2001. http://dx.doi.org/10.5382/gb.35.15.
Full textAbstract:
Abstract Massive sulfide deposits of the Vermont copper belt yielded approximately 3.6 Mt of ore during intermittent production from 1793 to 1958. The deposits consist of stratabound and generally stratiform pyrrhotite, chalcopyrite, and minor sphalerite and pyrite within metasedimentary rocks and minor mafic metavolcanic rocks of Silurian to Early Devonian age. At the largest deposits (Elizabeth, Ely, Pike Hill), massive sulfides are generally associated with metabasaltic amphibolite. The deposits are structurally complex, and have been deformed together with their host rocks during two stages of nappe-related, largely isoclinal folding, and during a later stage of dome-related folding; syntectonic shears and thrust faults commonly mark the contacts between massive sulfide bodies and silicate wall rocks. Postore re-gional metamorphism took place under amphibolite-grade conditions, producing locally abundant kyanite and staurolite in pelitic country rocks during peak prograde events. Geochemical studies of clastic metasedimentary host rocks in the district indicate a significant mafic component that suggests a continental island-arc provenance. The amphibolites, in contrast, have immobile trace element and rare earth element (REE) geochemical signatures similar to that of midocean ridge basalt (MORB). Lithologically unusual wall rocks at the Elizabeth deposit, including coarse garnet-mica schist, laminated plagioclase-rich granofels, quartz-mica-carbonate schist, tremolite-phlogopite schist, and quartz-albite tourmalinite, have high contents of Cr and MORB-type REE patterns that suggest protoliths of tholeiitic basalt. Massive sulfide, metachert, Mn-rich garnet-quartz rocks (coticule), and magnetite iron formation in the district are believed to have formed as exhalative chemical precipitates on the sea floor. Chemical analyses of unoxidized massive sulfide from the Elizabeth, Ely, and Pike Hill mines show that in addition to very high Cu (to 23.6 %) and in rare cases very high Zn (to 26.2 %), some ore samples contain minor Ag (to 100 ppm), Au (to 0.85 ppm), Cd (to 1500 ppm), Co (to 1469 ppm), Mn (to 5600 ppm), Mo (to 420 ppm), and Se (to 87 ppm). The ores have uniformly low As, Ba, Bi, Cr, Hg, Ni, Pb, REEs, Sb, Sn, Te, Th, Tl, U, and W. The overall geologic and geochemical features of the Vermont copper belt ores are similar to those of the Besshi deposits in Japan. Possible modern analogs include the actively forming massive sulfides of Guaymas Basin in the Gulf of California, Escanaba Trough on the Gorda Ridge, and Middle Valley on the Juan de Fuca Ridge.
Conference papers on the topic "Exhalation rate"
1
Jiang, Fuliang, Xiaoli Wang, Shuai Zhang, Xiangyang Li, and Changshou Hong. "Experimental Study of Radon Exhalation Rate in Uranium-Like Rock Based on Closed Chamber Method." In 2018 26th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icone26-81067.
Full textAbstract:
The closed chamber method is widely used in measuring radon exhalation rate, which can avoid the error caused by the leakage and anti-diffusion phenomena. Firstly, considering the actual situation that uranium ore is difficult to obtain and have a high radioactivity, the uranium-like rock was made according to the similarity theory. Secondly, the diffusion length and intrinsic radon exhalation rate were obtained by using the closed chamber method. Thirdly, the theoretical values of radon exhalation rate made by uranium-like ore block were calculated, compared with the measured values. This study shows that the uranium-like rock block made by the best mass ratio is helpful for the subsequent experiment, and the error between the theoretical calculation and the measured value is no more than 9.14%. This indicates it is reliable to estimate radon exhalation rate by diffusion length and intrinsic radon exhalation rate and can also provide a foundation for rapidly gaining radon exhalation rate of the same type material by the closed chamber method. This study can further promote the study of the radon exhalation rate under the complex physical conditions and then better guide the protection work of radon radiation in underground mining.
2
Goto, Masayoshi, Jun Moriizumi, Hiromi Yamazawa, et al. "Estimation of global radon exhalation rate distribution." In THE NATURAL RADIATION ENVIRONMENT: 8th International Symposium (NRE VIII). AIP, 2008. http://dx.doi.org/10.1063/1.2991199.
Full text
3
Masahiro, Hosoda, Shimo Michikuni, Sugino Masato, et al. "Radon and Thoron exhalation rate map in Japan." In THE NATURAL RADIATION ENVIRONMENT: 8th International Symposium (NRE VIII). AIP, 2008. http://dx.doi.org/10.1063/1.2991202.
Full text
4
Faris KADDOORI, Farah, Ban Sabah HAMEED, and Basim Khalaf REJAH. "RADON CONCENTRATION AND ITS EXLATION RATE IN TEA SAMPLES." In IV.International Scientific Congress of Pure,Appliedand Technological Sciences. Rimar Academy, 2022. http://dx.doi.org/10.47832/minarcongress4-23.
Full textAbstract:
In the various houses and cafes on the market, social spaces, and tourism, Iraqis are among the most tea-drinking people. Several experts in Iraq and around the globe are interested in investigating the radiation activity of tea in order to determine the radiation hazards linked with both the lives and health of tea addicts. In this research, A plastics nuclear path detector (CR-39) was used to explain the results of radon concentrations and Rn-222 exhalation rates in nine tea specimens. Specimen were taken from a variety of regional Iraqi markets. The chemical then drilling with NaOH solution at 70°C for 8 hours to identify the subsurface paths, which were subsequently analyzed with sufficient resolution by optical microscopes. The radon levels varied between (137.129 - 25.4092) Bq/cm3, with the mean being 72.687 Bq/cm3. The percentage of radon exhalation varied from (15.76981– 2.922053), with an average of 8.359 mBq/m3. h. Exhalation percentage and radon levels have a positive connection (R2 = 0.893). The results of the specimen revealed that its health hazards were not harmful. The findings of research study were contrasted to the findings of other studies that contained other food products and concluded that they were within globally allowed limits and did not pose a hazard to human health and life
5
Avramović, Dragan, Igor Čeliković, Predrag Ujić, et al. "RADON EXHALATION RATE OF SOME BUILDING MATERIALS COMMON IN SERBIA." In RAD Conference. RAD Association, 2019. http://dx.doi.org/10.21175/radproc.2018.26.
Full text
6
Singh, Lalit Mohan, K. Y. Singh, Ajay Mahur, Dinesh Kumar, and Devesh Gupta. "Measurement of radon exhalation rate using solid state nuclear track detector." In ADVANCES IN BASIC SCIENCE (ICABS 2019). AIP Publishing, 2019. http://dx.doi.org/10.1063/1.5122505.
Full text
7
Jiang, Fuliang, Wenchao Yang, Ming Li, Xiangyang Li, and Changshou Hong. "Noise Reduction Treatment and Analysis of Accumulated Radon Concentration in Uranium-Like Rock Based on Wavelet Theory." In 2018 26th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icone26-81068.
Full textAbstract:
Based on the principle of similarity, uranium ore samples were prepared from raw materials such as uranium tailings, quartz sand and refined iron powder, and then the samples were treated with different packages for measuring the sample accumulated radon concentration. In the actual measurement process, due to the characteristics of radionuclide decay, instrument reasons and human factors, the data will be a certain deviation. Therefore, the method of wavelet analysis is used to denoise the accumulated radon concentration and obtain radon exhalation rate. The results of the study show: the correlation coefficient of cumulative radon concentration fitted by wavelet denoising is improved greatly, and all of them are above 0.99, the recalculated radon exhalation rate of the single side of the sample is decreased by 0.06Bq · m−2 · s−1, and double-edged is decreased by 0.02Bq · m−2 · s−1. The experiment proved that wavelet theory can be used to correct calculated value of radon exhalation rate of uranium-like rock. At the same time, it provides a new method for further study of uranium mine radiation protection parameters.
8
Nsiah-Akoto, Irene, Aba Bentil Andam, T. Tettey Akiti, and J. J. Flectcher. "Study of radium and radon exhalation rate in soil samples, Offinso municipality." In WOMEN IN PHYSICS: 6th IUPAP International Conference on Women in Physics. AIP Publishing, 2019. http://dx.doi.org/10.1063/1.5110138.
Full text
9
Lei, Zhipeng, and James Yang. "Computing Carbon Dioxide and Humidity in Filtering Facepiece Respirator Cavity During Breathing Cycles." In ASME 2014 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/detc2014-34660.
Full textAbstract:
Carbon dioxide (CO2) and humidity are two factors that affect respirator comfort. Whenever one uses a respirator, CO2 is reinhaled from the previous exhalation and the humidity inside the respirator cavity increases. The CO2 reinhalation causes respirator discomfort with symptoms like headache, dizziness, and etc. The increased humidity causes respirator thermal discomfort. Experimental researches focused on measuring the CO2 and humidity values in the respirator cavity during a long period of time (over 1 hour). However, these experiments ignored CO2 and humidity value variation during a breathing cycle within the respirator cavity. The objective of this study was to use computational fluid dynamics (CFD) method to calculate the CO2 and humidity values inside the respirator cavity during four breathing cycles (19.2s). In our previous work the contact between a headform and a filtering facepiece respirator (FFR) was simulated by the using finite element modeling. In this work a meshed domain was generated including the FFR cavity, the FFR and the region outside of the FFR. A breathing cycle, having both exhalation and inhalation, was then defined as a time-dependent flow rate through a breathing opening (nasal breathing, mouth breathing, and nasal-mouth breathing). Using CFD method, the breathing air flow and the species transport of CO2 and water vapor (H2O) in the domain were simulated for 4 breathing cycles. Totally 5 tests with different breathing openings and different breathing flow rates were conducted: nasal breathing with base, 2 and 3 times flow rate, mouth breathing with base flow rate, and nasal-mouth breathing with base flow rate. The simulation results showed that there were large CO2 and H2O value variations (CO2 mass fraction from 0 to 0.074 and H2O mass fraction 0.0077 and 0.0151) in the FFR cavity during a breathing cycle. The inhaled CO2 mole fraction decreased with increasing breathing flow rate. With the base flow rate, during inhalation the middle point between the nostrils and mouth had higher relative humidity than other probing positions did.
10
Pulat, O., and R. N. Parthasarathy. "Flow and Pressure Measurement in a Selective Laser Sintered Human Tracheobronchial Airway Model Under Cyclic Flow Conditions." In ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56078.
Full textAbstract:
A selectively laser sintered human tracheobronchial airway model was used to study periodic flows at different frequencies corresponding to inhalation and exhalation. The model was fabricated from a 3-d point could based on the Visible Human Male Project. The objective was to document the volumetric flow rate and pressure drop under periodic flow conditions and compare these values with those obtained in steady flow. The flow was cycled via a Programmable Logic computer (PLC) at a specified breathing frequency of 12 breaths per minute. The tracheal flows rate studied were 30, 50, and 120 liters per minute. The results indicated that significant differences existed between flow measurements made under steady conditions and periodic conditions; these differences became significant at high flow rates. The flow distribution in the right and left side of the airway model was asymmetric. The results also indicated the existence of both turbulent and laminar flow regimes at all tracheal flow rates.
Reports on the topic "Exhalation rate"
1
Peter, J. M., and M. G. Gadd. Introduction to the volcanic- and sediment-hosted base-metal ore systems synthesis volume, with a summary of findings. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/328015.
Full textAbstract:
This volume presents results of research conducted during phase 5 of the Volcanic- and Sedimentary-hosted Base Metals Ore Systems project of the Geological Survey of Canada's Targeted Geoscience Initiative (TGI) program. The papers in this volume include syntheses and primary scientific reports. We present here a synopsis of the findings during this TGI project. Research activities have addressed several mineral deposit types hosted in sedimentary rocks: polymetallic hyper-enriched black shale, sedimentary exhalative Pb-Zn, carbonate-hosted Pb-Zn (Mississippi Valley-type; MVT), and fracture-controlled replacement Zn-Pb. Other carbonate-hosted deposits studied include a magnesite deposit at Mount Brussilof and a rare-earth element-F-Ba deposit at Rock Canyon Creek, both of which lack base metals but are spatially associated with the MVT deposits in the southern Rocky Mountains. Volcanogenic massive-sulfide deposits hosted in volcanic and mixed volcanic-sedimentary host rock settings were also examined. Through field geology, geochemical (lithogeochemistry, stable and radiogenic isotopes, fluid inclusions, and mineral chemistry), and geophysical (rock properties, magnetotelluric, and seismic) tools, the TGI research contributions have advanced genetic and exploration models for volcanic- and sedimentary-hosted base-metal deposits and developed new laboratory, geophysical, and field techniques to support exploration.
2
Scanlan, E. J., M. Leybourne, D. Layton-Matthews, A. Voinot, and N. van Wagoner. Alkaline magmatism in the Selwyn Basin, Yukon: relationship to SEDEX mineralization. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328994.
Full textAbstract:
Several sedimentary exhalative (SEDEX) deposits have alkaline magmatism that is temporally and spatially associated to mineralization. This report outlines interim data from a study of potential linkages between magmatism and SEDEX mineralization in the Selwyn Basin, Yukon. This region is an ideal study site due to the close spatial and temporal relationships between SEDEX deposits and magmatism, particularly in the MacMillan Pass, where volcanic rocks have been drilled with mineralization at the Boundary deposit. Alkaline volcanic samples were analysed from the Anvil District, MacMillan Pass, Keno-Mayo and the Misty Creek Embayment in the Selwyn Basin to characterise volcanism and examine the relationship to mineralization. Textural and field relationships indicate a volatile-rich explosive eruptive volcanic system in the MacMillan Pass region in comparison to the Anvil District, which is typically effusive in nature. High proportions of calcite and ankerite in comparison to other minerals are present in the MacMillan system. Cathodoluminescence imaging reveals zoning and carbonate that displays different luminescent colours within the same sample, likely indicating multiple generations of carbonate precipitation. Barium contents are enriched in volcanic rocks throughout the Selwyn Basin, which is predominately hosted by hyalophane with rare barite and barytocalcite. Thallium is positively correlated with Ba, Rb, Cs, Mo, As, Sb and the calcite-chlorite-pyrite index and is negatively correlated with Cu. Anvil District samples display a trend towards depleted mid-ocean ridge mantle on a plot of Ce/Tl versus Th/Rb. Hydrothermal alteration has likely led to the removal of Tl from volcanic rocks in the region. Ongoing research involves: i) the analysis of Sr, Nd, Pb and Tl isotopes of volcanic samples; ii) differentiating magmatic from hydrothermal carbonate using O, C and Sr isotopes; iii) examining sources of Ba in the Selwyn Basin; iv) and constraining age relationships through U-Th-Pb geochronology.
3
Mueller, C., S. J. Piercey, M. G. Babechuk, and D. Copeland. Stratigraphy and lithogeochemistry of the Goldenville horizon and associated rocks, Baie Verte Peninsula, Newfoundland. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328990.
Full textAbstract:
The Goldenville horizon in the Baie Verte Peninsula is an important stratigraphic horizon that hosts primary (Cambrian to Ordovician) exhalative magnetite and pyrite and was a chemical trap for younger (Silurian to Devonian) orogenic gold mineralization. The horizon is overlain by basaltic flows and volcaniclastic rocks, is intercalated with variably coloured argillites and cherts, and underlain by mafic volcaniclastic rocks; the entire stratigraphy is cut by younger fine-grained mafic dykes and coarser gabbro. Lithogeochemical signatures of the Goldenville horizon allow it to be divided into high-Fe iron formation (HIF; &amp;gt;50% Fe2O3), low-Fe iron formation (LIF; 15-50% Fe2O3), and argillite with iron minerals (AIF; &amp;lt;15% Fe2O3). These variably Fe-rich rocks have Fe-Ti-Mn-Al systematics consistent with element derivation from varying mineral contributions from hydrothermal venting and ambient detrital sedimentation. Post-Archean Australian Shale (PAAS)-normalized rare earth element (REE) signatures for the HIF samples have negative Ce anomalies and patterns similar to modern hydrothermal sediment deposited under oxygenated ocean conditions. The PAAS-normalized REE signatures of LIF samples have positive Ce anomalies, similar to hydrothermal sediment deposited under anoxic to sub-oxic conditions. The paradoxical Ce behaviour is potentially explained by the Mn geochemistry of the LIF samples. The LIF have elevated MnO contents (2.0-7.5 weight %), suggesting that Mn from hydrothermal fluids was oxidized in an oxygenated water column during hydrothermal venting, Mn-oxides then scavenged Ce from seawater, and these Mn-oxides were subsequently deposited in the hydrothermal sediment. The Mn-rich LIF samples with positive Ce anomalies are intercalated with HIF with negative Ce anomalies, both regionally and on a metre scale within drill holes. Thus, the LIF positive Ce anomaly signature may record extended and particle-specific scavenging rather than sub-oxic/redox-stratified marine conditions. Collectively, results suggest that the Cambro-Ordovician Taconic seaway along the Laurentian margin may have been completely or near-completely oxygenated at the time of Goldenville horizon deposition.