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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

An investigation into the use of biokinetic models when assessing intakes of plutonium

Hrycushko, Brian Andrew 10 October 2008 (has links)
The goal of internal dosimetry is to assess the dose to an individual from an intake of a radionuclide. This usually encompasses assessing the intake amount based on some form of bioassay measurement used with a biokinetic model. There are many published biokinetic models that describe the transfer of radionuclides throughout the body. It would be beneficial at times if one could interchange certain biokinetic models with another to assess an intake based on bioassay data to save time and make calculations simpler. This research compared the daily excretion rates by interchanging widely used biokinetic models in different combinations. These model combinations were then used to assess an unknown intake of a case study. It was shown that the ICRP-30 and ICRP-66 respiratory tract models can only be interchanged at specific times post intake to give similar excretion results from an inhalation intake. It is feasible to interchange the ICRP-67 plutonium systemic model or the newer Luciani and Polig plutonium systemic model to assess an intake based on fecal bioassay data, but not urine bioassay data for ingestion intakes. It is not feasible to interchange the systemic models when assessing intakes from a wound or injection. Using different combinations of biokinetic models predicted intakes within 30% for a case study which included a relatively long inhalation chronic intake followed by a much shorter chronic inhalation intake. It was shown that the predicted initial chronic intake for each combination of models gave fecal excretion values which deviated the most from the worker's fecal bioassay data. This could mean that the biokinetic models yield inaccurate excretion rates for long chronic intakes.
2

An investigation into the use of biokinetic models when assessing intakes of plutonium

Hrycushko, Brian Andrew 10 October 2008 (has links)
The goal of internal dosimetry is to assess the dose to an individual from an intake of a radionuclide. This usually encompasses assessing the intake amount based on some form of bioassay measurement used with a biokinetic model. There are many published biokinetic models that describe the transfer of radionuclides throughout the body. It would be beneficial at times if one could interchange certain biokinetic models with another to assess an intake based on bioassay data to save time and make calculations simpler. This research compared the daily excretion rates by interchanging widely used biokinetic models in different combinations. These model combinations were then used to assess an unknown intake of a case study. It was shown that the ICRP-30 and ICRP-66 respiratory tract models can only be interchanged at specific times post intake to give similar excretion results from an inhalation intake. It is feasible to interchange the ICRP-67 plutonium systemic model or the newer Luciani and Polig plutonium systemic model to assess an intake based on fecal bioassay data, but not urine bioassay data for ingestion intakes. It is not feasible to interchange the systemic models when assessing intakes from a wound or injection. Using different combinations of biokinetic models predicted intakes within 30% for a case study which included a relatively long inhalation chronic intake followed by a much shorter chronic inhalation intake. It was shown that the predicted initial chronic intake for each combination of models gave fecal excretion values which deviated the most from the worker's fecal bioassay data. This could mean that the biokinetic models yield inaccurate excretion rates for long chronic intakes.
3

Investigation of Trace Uranium in Biological Matrices

Miller, James Christopher 16 December 2013 (has links)
A system for the analysis of urine bioassay samples for the purpose of inversely investigating an unknown exposure to uranium has been developed. This technique involves the use of a thin flow electrochemical cell in conjunction with an anodized glassy carbon electrode to selectively separate uranium atoms out of solution for later analysis on an inductively coupled plasma mass spectrometer. A series of uranium urinalysis bioassay sample results can be used to investigate the time frame and type of exposure. This analysis uses an exposure database and regression analysis to best fit urinalysis uranium excretion data to expected profiles using commercially available mathematics software. The least number of data points to determine an acceptable confidence interval is ten bioassay samples taken at least a week apart. The system was benchmarked using a random sampling of urinary excretion samples from a known case at the Y-12 plant in the 1960’s. The electrochemical system was characterized using U.S. Department of Energy synthetic urine quality assurance standards from an inter-laboratory exercise in 2012. The separation apparatus was able to consistently separate uranium from the synthetic urine solutions with a consistent recovery between ten and fifteen percent and up to fifty percent. The method is isotope independent and maintains the enrichment of any excreted material. This allows for the material to be compared to operational logbooks at facilities using multiple enrichments in the nuclear fuel cycle. This methodology is recommended for spot estimation in support of a traditional bioassay program.
4

Determination of biokinetic parameters of wastewater biofilms from oxygen concentration profiles

Okafor, Sabinus Unknown Date
No description available.
5

A generic biokinetic model for C-14 labelled compounds

Manger, Ryan Paul 07 July 2010 (has links)
Carbon-14, a radioactive nuclide, is used in many industrial applications. Due to its wide range of uses in industry, many workers are at risk of accidental internal exposure to 14C. Being a low energy beta emitter, 14C is not a significant external radiation hazard, but the internal consequences posed by 14C are important, especially because of its long half life of 5730 years. The current biokinetic model recommended by the International Commission on Radiological Protection (ICRP) is a conservative estimate of how radiocarbon is treated by the human body. The ICRP generic radiocarbon model consists of a single compartment representing the entire human body. This compartment has a biological half life of 40 days yielding an effective dose coefficient of 5.8×10-10 Sv Bq-1. This overestimates the dose of all radiocarbon compounds that have been studied. An improved model has been developed that includes and alimentary tract, a urinary bladder, CO2 model, and an "Other" compartment used to model systemic tissues. The model can be adapted to replicate any excretion curve and excretion pattern. In addition, the effective dose coefficient produced by the updated model is near the mean effective dose coefficient of carbon compounds that have been considered in this research. The major areas of improvement are: more anatomically significant, a less conservative dose coefficient, and the ability to manipulate the model for known excretion data. Due to the wide variety of carbon compounds, it is suggested that specific biokinetic models be implemented for known radiocarbon substances. If the source of radiocarbon is dietary, then the physiologically based model proposed by Whillans that splits all ingested radiocarbon compounds into carbohydrates, fats, and proteins should be used.
6

An Assesement of Iodine-129 and Iodine 127 in Human Biological Materials with Modelling of Dietary Iodine Intake and Excretion

Almarshadi, Fahad Awwadh 03 June 2022 (has links)
This thesis concerned with iodine status, sources in human body, and measurements especially here in Canada, where iodine status for the Canadian population is not well known. With the recent re-emergence of iodine deficiency among individuals in other industrial countries, understanding the main sources of iodine to the Canadian population is necessary to ensure fortification strategies are justified and effective. Uncertinaty has arisen to the importance of iodized salt recently, along with medical warnings to reduce salt consumbtion. This conflicts give rise to improve scientific research and hone thier methods with new applications. The research question here is that: Can we benefit from the existence of long-lived radioiodine-129 in the environment and explore its potential as a tracer? To answer this question, the study was divided into an introductory chapter contains a review about the topic, then three research chapters. The second chapter was devoted to study the possibility of extracting 129I from human urine. As for third chapter of the thesis, it was about refining a method that already established, and use it to extract 129I from breastmilk using combustion, then determine the radiological dose of 129I in infants’ thyroid. While the fourth chapter was devoted to investigate the main sources of 127I and 129I in the Canadian diet based on daily food consumption and modelling the urinary iodine concentration for adults and infants through the novel application of a well-established compartment model implemented in AMBER. The path of this thesis was crowned with a set of results, which are detailed in the end of each chapter as follow: 1- The advantage of accelerator mass spectrometry (AMS) helps to measure 129I in human urine for the first time. The result for 25 participants from Ottawa ranged from 3.3 x 106 atoms/L to 884 x 106 atoms/L with a median of 108.7 x 106 atoms/L, and the 129I/127I ratio ranged from 7.38 x 10-12 to 3.97 x 10-10 with a mean of 1.3 x 10-10. 2- The concentration of 127I and 129I in Ottawa urine samples were significantly correlated and generally similar to the 129I concentrations and 129I/127I ratios from environmental samples collected around Ottawa. 3- This correlation suggests that 129I could be a potential nutritional tracer of dietary iodine. 4- In chapter 3, the 129I in breastmilk ranged from 1.26x108 atoms/L to 6.64x108 atoms/L with a median of 2.10 x108 atoms/L, and the 129I/127I ratio ranged from 1.27x10-10 to 9.9x10-10 with a median of 2.13x10-10. 5- A correlation was also observed between 127I and 129I concentrations in breastmilk. 6- The isotopic ratios in breastmilk were similar to Canadian cow’s’ milk, indicating that the milk of both cows and humans is a reflection of the 129I concentration of their local environment and the food ingested. 7- Result from chapter 3 confirms that humans are exposed to the 129I from birth through their mother breastmilk, giving them an average dose of 1.10 x10-4 Bq/year and thyroid dose rate equal to 5.92 x10-10 Sv/year. 8- In fourth chapter, the daily milk consumption was measured for 78 mother-infants’ pairs, and ranged from 275 -1202 g/day, with a mean of 731 g/day. This value agrees well with global infant milk intake which estimated at 730g/day. 9- The daily iodine intake from breastmilk ranged from 11.2 µg/day to 476.2 µg/day with a median of 127.9 µg/day. 10- The urinary iodine concentrations were estimated without urine collection using iodine biokinetic model, giving a median urinary iodine concentration (n=78) at 304.7 µg/L. The result was compared to those measured by Health Canada (median= 398.7 µg/L), showing a moderate correlation (r= 0.496). 11- A further comparison of the results was made based on gender shows that the difference between UIC in male and female infants measured by Health Canada and those estimated by AMBER is non-significant. 12- Through AMBER software, the influence of seven common diets on UICs was assessed to determine which foods play an important role in ensuring iodine adequacy. We observed that the main source of iodine in a vegan diet is grain products providing up to 70%, while in remaining diets the main source of iodine was dairy products (50-69%) when they are consumed. 13- The contribution of iodized salt to all Canadian diets was ranked second, after dairy, unless the diet is vegan or ovo-vegetarian, where dairy is not consumed, iodized salt was ranked first. 14- Among 23 scenarios for seven different diets, the urinary iodine-129 concentrations ranged from 1.4 x10-7 to 3.3 x10-7 µg/L with a median of 3.1 x10-7 µg/L, and the isotopic 129I/127I ratio ranged from 1.1 x10-9 to 1.2 x10-8 with a median of 2.8 x10-9. 15- In contrast to stable iodine, the highest isotopic ratio was observed in vegan diet, while the lowest was observed in ketogenic diet. This suggests that grain products are the main contributor of 129I to humans. 16- Despite being the primary contributors of stable iodine (127I), salt and dairy show a lower contribution of 129I. Based on this we can qualitatively predict the source of iodine 127 using isotopic ratio 129I/127I. For example, in cases where the isotopic ratio was between 10-8 and 10-9, therefore, the main sources of iodine in this person may be from grains products, vegetables, and fruits; and in cases where the isotopic ratio was between 10-10 and 10-11, therefore, the main sources of iodine in this person may be from dairy products and some contribution from salt. This study has shown the capability of 129I to be used in biomedical fields. In this thesis 129I used as a nutritional tracer where it helps to detect the sources of stable iodine in human body based on isotopic ratio. The extraction method invented in Chapter 2 can be used to evaluate 129I exposure directly in the human body for those who live nearby nuclear fuel reprocessing plants. An additional application for this method can be in assessing 129I in human to investigate 131I uptake in the event of a nuclear emergency using 129I in urine as a proxy. Moreover, the extraction technique used Chapter 3, can be extended to other biological samples such as thyroid or brain. Furthermore, Chapter 4 shows that with the right estimation of daily iodine intake and urine volume, a biokinetic model of iodine, built in the AMBER software, can predict urinary iodine concentration with a high degree of accuracy without collecting urine samples.
7

A Batch Biokinetic Study of the Preferential Separation of a Mixed Culture of Microorganisms Using Small-Size Hydrocyclones

Pollock, T. E. 09 1900 (has links)
<p> The thickening and classifying characteristics of small size hydrocyclones were investigatedo Test slurries, consisting of mixed cultures of microorganisms in water. were partitioned into two fractions by hydrocyclones ranginq in size from 2 mm to 10 mm body diameter which operated at inlet pressures ranging from 80 to 200 psi and volume splits ranginq from 1.0 to 3.0. </p> <p> The classtfyino response was defined in terms of the relative magnitudes of the specific growth rate of the two fractions as determined by coincident observation of duplicate batch biological reactors each seeded with one portion of the partitioned slurry. </p> <p> The thickening response was defined by the Rietema-Tenbergen separation efficiency. </p> <p> The biokinetic aspects of this investigation are emphasized in this manuscript. </p> / Thesis / Master of Engineering (MEngr)
8

Vyhodnocení silových předpokladů pro plavání špičkových triatlonistů v ročním cyklu 2009-2010 / Evaluation of force presumptions for swimming triathletes from Czech team in training cycle 2009-2010

Švejda, Roman January 2011 (has links)
Title: Evaluation of force presumptions for swimming triathletes from Czech team in training cycle 2010-2011 Intention of work: Evaluation of specific force presumptions for swimming and ability maximal utilit force efficiency in long time stress, wide spektrum of triatlonist from beginners to elite czech competitors. For evaluation we used 3 indikators: 1. average Power Output - PO - [W] 2. average power output on kg body weight - PO.kg-1 - [W.kg-1 ] 3. complete work - W - [Nm] Method: Testing on swim trainer Biokinetic by tests which simulated free style strokes and butterfly strokes. 10 strokes by free style and butterfly styl, 50 and 100 strokes by butterfly style. Results: Some people lives in mistake about their directionality. Someone think, that he is better for long distance, and oposit eis true. Lot of people, in our test, made more work [Nm] in free style strokes, than butterfly strokes. More offen people made more work [Nm] in butterfly strokes. Our people swim butterfly just especialy and that's the reason, why they have more force in crowl. Keywords: Biokinetic, triathlon, swimming, testing, swim force.
9

Stanovení křivky kritického výkonu v plavání u triatlonistů / Curve- fitting of the critical power in swimming for triathletes

Zikmund, Jan January 2017 (has links)
Tittle: Curve- fitting of the critical power in swimming for triathletes Objectives: Comparison of curve-fitting of the critical power at swimmers and triathletes in different performance categories. Methods: This thesis is based on a research. The research took place in laboratories FTVS UK and there was used the swimming simulator called Biokinetic for test measurements. Elite swimmers, triathletes and hobby triathletes participated in the tests. Sportsmen took part in 4 tests. The first test - 10 crawl strokes, the second test - 20 crawl strokes, the third test - 50 crawl strokes and the fourth test - 200 crawl strokes. The obtained data were worked out by using T-test and they were written into tables and charts in programs Excel and Word. There was used program PASW Statistics 18 for statistical processing. Results: It was discovered, that there were no differences in performances in tests by using Biokinetic between swimmers and triathletes. Hobby triathletes made the same performances as elite triathletes. The biggest difference in performances was at female hobby triathletes, who were worse than female elite triathletes and female swimmers. Keywords: Critical power, swimming, triathlon, Biokinetic, testing
10

Vliv posilovacího cvičení na Biokineticu do plaveckého výkonu na 50 m kraul / Effect of strengthening exercises on Biokinetic to swimming performance at 50 m crawl

Nezdara, Jaroslav January 2019 (has links)
Title: Effect of strengthening exercises on Biokinetic to swimming performance at 50 m crawl. Objectives: The aim of this work is to find out whether a two-month movement intervention performed on a swimming simulator (Biokinetic) will affect the swimming performance of a 50 m crawl by FTVS students. Methods: Five probands of the 2nd year of the follow-up study at Charles University FTVS participated in the research. The anthropometric data were obtained using the TANITA testing device. To determine the maximum endurance muscle strength of the upper limbs and other movement parameters, we used the Biokinetic device. In order to determine the maximum swimming performance, we carried out a swimming test for 50 m with the crawl technique. Interest activities were identified through a questionnaire. Data were analyzed by MS EXCEL and NCSS 2019. Results:The results show, that the Biokinetic weight training exercises had a positive influence on swimming performance at a distance of 50 m crawl in swimming pool. In the analysis of the technique of performing motion shots on Biokinetic, we found an increase in the frame frequency, but a decrease in the overall path. The increased in frequency according to our findings results in a reduction of the total path of the motion cycles. All probands experienced an...

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