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Статті в журналах з теми "Produit dose-Surface":
1
Dousteyssier, M. C., S. Garnier, and D. Sirinelli. "Calcul du produit dose surface au cours des examens de radiopediatrie : interet en pratique quotidienne." Journal de Radiologie 85, no. 9 (September 2004): 1431. http://dx.doi.org/10.1016/s0221-0363(04)77404-1.
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Chateil, J. F., C. Rouby, M. Brun, C. Labessan, and F. Diard. "Mesure pratique de l’irradiation en radiopédiatrie : utilisation du produit dose surface en fluorographie numérique et pour les radiographies pulmonaires néonatales." Journal de Radiologie 85, no. 5 (May 2004): 619–25. http://dx.doi.org/10.1016/s0221-0363(04)97638-x.
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Garnier, S., M. C. Dousteyssier, C. Sembely-Taveau, M. Boscq, and D. Sirinelli. "Mise en place de la mesure du produit dose X surface (PDS) dans un service de radio-pediatrie : utilisation en pratique quotidienne." Journal de Radiologie 85, no. 9 (September 2004): 1460. http://dx.doi.org/10.1016/s0221-0363(04)77505-8.
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Been, Thomas, and Corrie Schomaker. "Fumigation of marine clay soils infested with Globodera pallida and G. rostochiensis using 1,3-dichloropropene and additional top soil treatments." Nematology 1, no. 1 (1999): 3–14. http://dx.doi.org/10.1163/156854199507929.
Анотація:
AbstractThree fields of marine clay soil were fumigated with 150 l/ha 1,3-dichloropropene (DD) (Telone IITM, Shell 95TM). On three dates after application, concentrations of Z - and E-1,3-dichloropropene were measured per 5 cm layer of soil to a depth of 40 cm and integrals of concentration time products were calculated. When the fumigant was no longer detectable, a top soil treatment with either 150 l/ha metam-sodium or 180 kg/ha dazomet (active compound methyl isothiocyanate) was applied, followed immediately by autumn ploughing. Soil samples were taken before and after fumigation and after the top soil treatment to extract potato cyst nematodes (PCN). Survival was determined from hatching tests. Mortality after the DD treatment, defined as the complement of the percentage of survival, was estimated for each 5 cm layer of soil to a depth of 30 cm to construct dosage response curves. Fumigation with DD killed 48, 48, and 72% of the PCN per field, respectively. Accelerated breakdown of DD by micro-organisms accounted for the two lower mortality rates. The additional top soil treatment with metam-sodium increased mortality to 90% or more. Dazomet, however, was less effective (53 and 80%) considering that twice as much of the active compound was applied as in the metam-sodium treatment. Multiplication, in pot experiments, of hatched juveniles originating from the injection layer after the DD treatment was 25% less than that of those from untreated plots. This was caused by a lower fraction of juveniles developing into cysts. PCN could be retrieved from soil layers as deep as 80 cm below the surface. Fumigation reached only a fraction of the infested soil, down to 25-30 cm. The infestation foci were so small compared to the standard minimum area fumigated (1 ha) that 90% of the active compound would be wasted on non-infested soil. Soil fumigation, whether or not combined with an additional top soil treatment, will seldom be profitable. Monitoring for infestation foci is recommended. Fumigation de sols argileux d'origine marine infestes par Globodera pallida et G. rostochiensis a l'aide de 1,3 dichloropropene et d'un traitement additionnel de surface - Trois champs au sol argileux d'origine marine ont ete traites avec 150 l/ha de 1,3 dichloropropene (DD) (Telone IITM, Shell 95TM). A trois moments apres le traitement, les concentrations en Z - et E-1,3 dichloropropene ont ete mesurees dans chaque couche de sol epaisse de 5 cm jusqu'a une profondeur de 40 cm et les integrales des produits concentration/temps calculees. Lorsque le produit fumigant n'etait plus detectable un traitement de surface a ete applique a l'aide de 150 l/ha de metam-sodium ou de 180 kg/ha de dazomet (matiere active: isothiocyanate de methyle), traitement immediatement suivi par un labour d'automne. Les nematodes a kyste de la pomme de terre (PCN) ont ete extraits d'echantillons de sol preleves avant et apres fumigation ainsi qu'apres le traitement de surface. La survie des nematodes a ete chiffree a l'aide de tests d'eclosion. Le taux de mortalite (= 100 - % de survie) apres traitement au DD a ete estime pour chaque couche de sol de 5 cm d'epaisseur jusqu'a 30 cm de profondeur pour permettre l'elaboration des courbes dose/effet. La fumigation au DD a tue respectivement 48, 48 et 79% des PCN par champ. La degradation acceleree du DD par des micro-organismes est rendue responsable de la faiblesse des deux premiers taux. Le traitement additionnel de surface accroit la mortalite jusqu'a 90% et plus. Le dazomet est cependant moins efficace (53 et 80%) si l'on considere que son compose actif a ete applique a une dose double de celle du traitement au metam-sodium. Dans les experimentations en pots, le taux de multiplication des juveniles eclos provenant des couches de sol ou le DD avait ete injecte a ete de 25% inferieur a celui des temoins. La cause en est le plus faible nombre de larves se developpant dans les kystes. Les PCN peuvent etre rencontres dans le sol a des profondeurs allant jusqu'a 80 cm. La fumigation n'atteint qu'une fraction de sol, situee a 20-30 cm de la surface. Les foyers d'infestation sont si reduits par rapport a la surface traitee (1 ha) que 90% de la matiere active est gaspillee dans du sol non infeste. La fumigation du sol, combinee ou non avec un traitement de surface, sera donc rarement rentable. La prise en consideration des foyers d'infestation est recommandee.
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Wade, J. P. "Estimation of effective dose in diagnostic radiology from entrance surface dose and dose-area product measurements." British Journal of Radiology 71, no. 849 (September 1998): 994–95. http://dx.doi.org/10.1259/bjr.71.849.10195022.
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Efthymiou, Fotios O., Vasileios I. Metaxas, Christos P. Dimitroukas, Stavros K. Kakkos, and George S. Panayiotakis. "KERMA-AREA PRODUCT, ENTRANCE SURFACE DOSE AND EFFECTIVE DOSE IN ABDOMINAL ENDOVASCULAR ANEURYSM REPAIR." Radiation Protection Dosimetry 194, no. 2-3 (May 2021): 121–34. http://dx.doi.org/10.1093/rpd/ncab082.
Анотація:
Abstract This study aims to evaluate patient radiation dose during fluoroscopically guided endovascular aneurysm repair (EVAR) procedures. Fluoroscopy time (FT) and kerma-area product (KAP) were recorded from 87 patients that underwent EVAR procedures with a mobile C-arm fluoroscopy system. Effective dose (ED) and organs’ doses were calculated utilising appropriate conversion coefficients based on the recorded KAP values. Entrance surface dose (ESD) was calculated based on KAP values and technical parameters. The mean FT was 22.7 min (range 6.4–76.8 min), resulting in a mean KAP of 36.6 Gy cm2 (range 2.0–167.8 Gy cm2), a mean ED of 6.2 mSv (range 0.3–28.5 mSv) and a mean ESD of 458 mGy (range 26–2098 mGy). The corresponding median values were 17.4 min, 25.6 Gy cm2, 4.4 mSv and 320 mGy. The threshold of 2 Gy for skin erythema was exceeded in two procedures for a focus-to-skin distance (FSD) of 40 cm and six procedures when an FSD of 30 cm was considered. The highest doses absorbed by the adrenals, kidneys, spleen and pancreas and ranged between 3.7 and 313.3 mGy (average 66.8 mGy), 3.3 and 285.1 mGy (average 60.8 mGy), 1.3 and 111.1 mGy (average 23.7 mGy), 1.1 and 92.1 mGy (average 19.6 mGy), respectively. A wide range of patient doses was reported in the literature. The radiation dose received by the patients was comparative or lower than most of the previously reported values. However, higher doses can be revealed due to the X-ray system’s non-optimum use and extended FTs, mainly affected by complex clinical conditions, patients’ body habitus and vascular surgeon experience. The large variation of patient doses highlights the potential to optimise the EVAR procedure by considering the balance between the radiation dose and the required image quality. Additional studies need to be conducted in increasing the vascular surgeons’ awareness regarding patient dose and radiation protection issues during EVAR procedures.
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Yakoumakis, E., I. A. Tsalafoutas, D. Nikolaou, I. Nazos, E. Koulentianos, and Ch Proukakis. "Differences in effective dose estimation from dose–area product and entrance surface dose measurements in intravenous urography." British Journal of Radiology 74, no. 884 (August 2001): 727–34. http://dx.doi.org/10.1259/bjr.74.884.740727.
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Dalah, Entesar Zawam. "Quantifying dose-creep for Skull and chest radiography using dose area product and entrance surface dose: Phantom study." Radiation Physics and Chemistry 167 (February 2020): 108231. http://dx.doi.org/10.1016/j.radphyschem.2019.03.035.
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Davoodi, Roya, Mohammad-Reza Eydian, Hessein Karampour, Mahdi Nassarpour, Reza Rezazadeh-Farokh, Asma Maraei, and Mohammad Chavideh. "Application of Dose Area Product (DAP) to Estimate Entrance Surface Dose (ESD) in Pediatric Chest X-Rays." Modern Health Science 3, no. 2 (August 17, 2020): p1. http://dx.doi.org/10.30560/mhs.v3n2p1.
Анотація:
Introduction: Given the high radiation tissue sensitivity of pediatric patients, it is necessary to monitor their received dose to optimize radiation protection. The first aim of this study was to evaluate the entrance surface dose (ESD) in pediatric patients undergoing a chest X-ray at the main hospital of Dezful, Iran. The second aim was to compare our results with the established dose reference levels (DRLs).
Materials and Methods: The studied population included 204 pediatric patients less than 15 years who were referred to as chest X-ray. A calibrated dose area product meter (DAP-meter) with permanent installation on the X-ray unit was used to radiation dose measurements. For each patient, the demographic data, exposure parameters and the dose read by DAP-meter were recorded and ESD was calculated using a standard mathematical formula.
Results: The average value of ESD was 119 μGy in patients less than 15 years. This value was 51.3, 122.3, 131.5 and 171.2 μGy for the age groups for less than 1 year, 1 to 5 years, 5 to 10 years and 10 to 15 years, respectively. A statistically significant difference was seen between ESD values in different age groups (P<0.001), whereas no statistical difference was seen between ESD values in girls and boys (P =0.993).
Conclusion: Pediatric patients in hospital investigated (except age group less than 1 year) are subjected to unnecessary radiation exposure, especially due to the use of non-optimize X-ray protocols.
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Milatovic, Aleksandra, Vesna Spasic-Jokic, and Slobodan Jovanovic. "Patient dose measurement and dose reduction in chest radiography." Nuclear Technology and Radiation Protection 29, no. 3 (2014): 220–25. http://dx.doi.org/10.2298/ntrp1403220m.
Анотація:
Investigations presented in this paper represent the first estimation of patient doses in chest radiography in Montenegro. In the initial stage of our study, we measured the entrance surface air kerma and kerma area product for chest radiography in five major health institutions in the country. A total of 214 patients were observed. We reported the mean value, minimum and third quartile values, as well as maximum values of surface air kerma and kerma area product of patient doses. In the second stage, the possibilities for dose reduction were investigated. Mean kerma area product values were 0.8 ? 0.5 Gycm2 for the posterior-anterior projection and 1.6 ? 0.9 Gycm2 for the lateral projection. The max/min ratio for the entrance surface air kerma was found to be 53 for the posterior-anterior projection and 88 for the lateral projection. Comparing the results obtained in Montenegro with results from other countries, we concluded that patient doses in our medical centres are significantly higher. Changes in exposure parameters and increased filtration contributed to a dose reduction of up to 36% for posterior-anterior chest examinations. The variability of the estimated dose values points to a significant space for dose reduction throughout the process of radiological practice optimisation.
Дисертації з теми "Produit dose-Surface":
1
Jurczak, Julien. "Produit dose-surface pour la radiothérapie : application aux protocoles de traitements stéréotaxiques." Thesis, université Paris-Saclay, 2022. http://www.theses.fr/2022UPASP025.
Анотація:
L'évolution des techniques de radiothérapie, en particulier avec l’avènement des traitements stéréotaxiques, a conduit à accroître l'utilisation de petits faisceaux d’irradiation permettant de se conformer au mieux au volume à traiter tout en minimisant l’irradiation des tissus sains environnants. Ce faisant, les conditions cliniques s'éloignent significativement des conditions de référence en dose absorbée dans l’eau en un point, telles que décrites dans les protocoles internationaux. La perte de traçabilité ainsi constatée conduit à une augmentation de l’incertitude sur la dose délivrée au patient. Afin de contourner les difficultés de traçabilité de la dose absorbée en petits champs, le Laboratoire National Henri Becquerel (LNHB) a proposé d’utiliser une approche novatrice. Au lieu de considérer une mesure en un point, une mesure intégrée sur une surface plus grande que le champ d'irradiation a été adoptée au travers d’une autre grandeur : le Produit Dose Surface (Dose Area Product ou DAP). Le travail présenté dans cette thèse porte sur la réalisation de références dosimétriques primaires en Produit Dose Surface dans l’eau (DAPw) pour des tailles de champs carrés et circulaires inférieures ou égales à 15 mm de côté ou de diamètre. En vue du transfert de ces nouvelles références dosimétriques à l’utilisateur, trois chambres d’ionisation plates de même surface sensible que le calorimètre graphite de grande section du LNHB ont été construites et étalonnées par rapport à la référence primaire nouvellement établie, avec une incertitude-type sur le coefficient d’étalonnage inférieure à 0.7% (k=1). Pour les tailles de champs comprises entre 5 mm et 15 mm, les trois chambres présentent le même comportement, avec un coefficient d’étalonnage indépendant de la forme du champ d’une part et qui augmente légèrement, de l’ordre de 1.7% en moyenne, avec la taille de champ d’autre part. Ces résultats prometteurs ouvrent la voie à un changement de par adigme pour la dosimétrie en petits champs.Afin de progresser en direction de l’utilisation clinique du DAP, en particulier au travers des mesures de facteurs d’ouverture du collimateur (FOC), une comparaison a été effectuée entre l’approche classique de la mesure en un point corrigée des facteurs fournis par le protocole IAEA TRS 483, et la dose absorbée en un point déduite du DAP grâce à la connaissance de la cartographie à deux dimensions du faisceau, accessible avec des films radiochromiques. C’est pour cette raison qu’il a été aussi développé dans cette thèse un nouvel instrument optique dédié à la lecture des films radiochromiques, compatible avec une application métrologique. Une fois adoptée, cette nouvelle approche permettrait d’améliorer le paramétrage des logiciels de planification de traitement (TPS), qui est un maillon essentiel de la chaîne de traitement en radiothérapieEvolution of radiotherapy techniques, in particular with the advent of stereotactic treatments, led to an increased use of small radiation beams allowing a better dose conformation to the volume while sparing the surrounding normal tissues. As a consequence, clinical conditions are significantly different from the reference conditions in terms of absorbed dose in water at a point, as described in international protocols. The loss of traceability thus observed leads to an increased uncertainty of the dose delivered to the patient. In order to overcome the difficulties of absorbed dose traceability in small fields, the Laboratoire National Henri Becquerel (LNHB) suggests an innovative approach. Instead of considering a point measurement, an integrated measurement over an area larger than the irradiation field was adopted through another quantity: the Dose Area Product (DAP). This thesis presents the establishment of primary standards in terms of Dose Area Product in water (DAPw) for square and circular field sizes less than or equal to 15 mm side or diameter. In order to transfer these new dosimetric standards to users, three plane-parallel ionization chambers with the same sensitive area than the large graphite calorimeter of the LNHB were constructed and calibrated against the newly established primary standards, with a standard uncertainty on the calibration coefficient of less than 0.7% (k=1). For field sizes between 5 mm and 15 mm, the three chambers show the same behavior, with a calibration coefficient that is independent of the field shape on the one hand and that increases slightly, about 1.7% on average, with the field size on the other hand. These promising results pave the way for a paradigm shift in small field dosimetry.In order to progress towards the clinical use of DAP, in particular through the measurement of field output correction factors (OF), a comparison was made between the classical approach of point measurement corrected by the factors provided by the IAEA TRS 483 protocol, and the absorbed dose at a point deduced from the DAP thanks to the knowledge of the two-dimensional mapping of the beam, which is accessible with radiochromic films. In that way, a new optical instrument dedicated to radiochromic films reading, compatible with a metrological application, was also developed in this thesis. Once adopted, this new approach would improve the parameterization of the treatment planning system (TPS), which is an essential link in the radiotherapy treatment chain
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McCanna, David. "Development of Sensitive In Vitro Assays to Assess the Ocular Toxicity Potential of Chemicals and Ophthalmic Products." Thesis, 2009. http://hdl.handle.net/10012/4338.
Анотація:
The utilization of in vitro tests with a tiered testing strategy for detection of mild ocular irritants can reduce the use of animals for testing, provide mechanistic data on toxic effects, and reduce the uncertainty associated with dose selection for clinical trials. The first section of this thesis describes how in vitro methods can be used to improve the prediction of the toxicity of chemicals and ophthalmic products. The proper utilization of in vitro methods can accurately predict toxic threshold levels and reduce animal use in product development. Sections two, three and four describe the development of new sensitive in vitro methods for predicting ocular toxicity. Maintaining the barrier function of the cornea is critical for the prevention of the penetration of infections microorganisms and irritating chemicals into the eye. Chapter 2 describes the development of a method for assessing the effects of chemicals on tight junctions using a human corneal epithelial and canine kidney epithelial cell line. In Chapter 3 a method that uses a primary organ culture for assessing single instillation and multiple instillation toxic effects is described. The ScanTox system was shown to be an ideal system to monitor the toxic effects over time as multiple readings can be taken of treated bovine lenses using the nondestructive method of assessing for the lens optical quality. Confirmations of toxic effects were made with the utilization of the viability dye alamarBlue. Chapter 4 describes the development of sensitive in vitro assays for detecting ocular toxicity by measuring the effects of chemicals on the mitochondrial integrity of bovine cornea, bovine lens epithelium and corneal epithelial cells, using fluorescent dyes.
The goal of this research was to develop an in vitro test battery that can be used to accurately predict the ocular toxicity of new chemicals and ophthalmic formulations. By comparing the toxicity seen in vivo animals and humans with the toxicity response in these new in vitro methods, it was demonstrated that these in vitro methods can be utilized in a tiered testing strategy in the development of new chemicals and ophthalmic formulations.
Книги з теми "Produit dose-Surface":
1
Hart, David, D. G. Jones, and B. F. Wall. Estimation of Effective Dose in Diagnostic Radiology from Entrance Surface Dose and Dose-area Product Measurement (NRPB). National Radiological Protection Board, 1994.
Частини книг з теми "Produit dose-Surface":
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Hickey, Anthony J., and Jay Holt. "Surface interactions in propellant driven metered dose inhaler product design." In Colloid and Interface Science in Pharmaceutical Research and Development, 79–102. Elsevier, 2014. http://dx.doi.org/10.1016/b978-0-444-62614-1.00004-1.
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Loredana Ungureanu, Elena, and Gabriel Mustatea. "Toxicity of Heavy Metals." In Heavy Metals - New Insights [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.102441.
Анотація:
Heavy metals are elements who exist naturally in the environment, but rapid urbanization and industrialization led to increased levels of these metals. These metals can reach the human body through food, water or air, where they have the property to accumulate in various tissues and organs for long periods of time and to produce serious effects on certain organs and the proper functioning of the body. Studies have also shown that heavy metals can have important effects, including on plants or animals. Their toxicity is dependent on factors such as dose, route of exposure, time of exposure, level of concentration, as well as age, gender, genetics, and nutritional status of exposed individuals. There is a growing interest from researchers to detect various physical, physical-chemical or microbiological methods to reduce or eliminate the presence of these metals, especially from surface or wastewater, which are mainly responsible for food contamination. This chapter present the main characteristics of heavy metals, the sources of contamination of exposure, as well as their toxicity on some environmental segments and especially on living organisms.
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Saleem, Moin, and Lisa Willcocks. "Minimal-change nephropathy and focal segmental glomerulosclerosis." In Oxford Textbook of Medicine, edited by John D. Firth, 4919–28. Oxford University Press, 2020. http://dx.doi.org/10.1093/med/9780198746690.003.0484.
Анотація:
Minimal-change nephrotic syndrome (MCNS) is an immune-mediated condition, usually of unknown cause. On light microscopy the glomeruli appear normal, and on electron microscopy there is effacement of epithelial cell foot processes over the outer surface of the glomerular basement membrane. MCNS is the cause of about 75% of cases of nephrotic syndrome in children and 17% in adults. Management and prognosis—treatment in adults is with prednisolone at an initial dose of 80 mg/day, then tapering. This leads to complete remission in 90 to 95% of patients, but 50 to 75% of glucocorticoid-responsive adults will have a relapse. Progression to renal failure is not expected and would call the diagnosis of MCNS into question. Focal segmental glomerulosclerosis (FSGS) is not a specific disease entity but a histological lesion, often of unknown aetiology, which is characterized by segmental areas of glomerular sclerosis. It may be (1) primary—either due to genetic mutation, or associated with an unknown circulating protein factor that causes an increase in glomerular permeability; or (2) secondary—the end product of a variety of pathological processes including glomerular hyperfiltration, healed glomerulonephritis, viral (including HIV) infection, or parasitic infection. Management and prognosis—corticosteroid and immunosuppressive therapy should be considered only in patients with primary FSGS and nephrotic syndrome. The steroid regimen is as used for MCNS, but with lesser success. Steroid-resistant cases are treated with ciclosporin (for which there is most published evidence), mycophenolate mofetil, or cyclophosphamide. Prognosis depends on histology and response to treatment.
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Sarathi Swain, Partha, Sonali Prusty, Somu Bala Nageswara Rao, Duraisamy Rajendran, and Amlan Kumar Patra. "Essential Nanominerals and Other Nanomaterials in Poultry Nutrition and Production." In Advances in Poultry Nutrition Research [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96013.
Анотація:
Poultry production, health and wellbeing are highly dependent upon formulation of balanced rations in terms of energy, protein, and micronutrients (vitamins and minerals). Among all, minerals are required in fewer quantities, but they are very important to maintain the productivity in poultry. Minerals present in the feeds are less bioavailable and additional supplementation is obligatory to meet the physiological demands of poultry. Conventionally, minerals are supplemented as inorganic salts, which are less absorbed and, thus, a major proportion is excreted to the surroundings creating environment issues. Nano-minerals and organic mineral chelates are other alternative to be used as livestock and poultry feed supplements. Though organic minerals are more bioavailable than inorganic salts, their high cost limits its use. In contrast, nano-minerals are relatively easy to synthesize at a lower cost. Nano-minerals are of the size from 1–100 nm and due to such small size, there is an enormous increase in surface area and thus their biological responses. The biological response studies have signified better retention of nano-minerals as compared to inorganic salts, and consequently leached less to the environment preventing possible pollution. Apart from these, nano-minerals have been shown to enhance growth, egg production and quality, immune-modulation and antioxidant status, and at the same time economize the production by reducing the supplemental dose of minerals and improving the feed conversion ratio. Some nano-minerals and other nanoparticles have strong antimicrobial effects, which have been shown to reduce pathogenic microorganisms in the gut. Nano-minerals seem to be less toxic than conventional mineral sources. Though less, few studies have indicated toxic effects of nano-mineral supplementation at higher dose of application, which should be validated by more programmed studies. Nanotechnology in poultry production system is still in its budding stage and more detailed studies are warranted to validate, establish and search for new effects of nano-minerals as they sometimes produce effects beyond expectation. This review highlights the biological responses of nanominerals on poultry production performance, quality of meat and eggs, tissue retention, immunity, antioxidant activity and antimicrobial actions compared with their conventional mineral sources.
Тези доповідей конференцій з теми "Produit dose-Surface":
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Lefort, C., B. Napoléon, R. Gincul, F. Fumex, and V. Lepilliez. "Evaluation des valeurs de produit dose surface délivrés lors des examens endoscopiques sous contrôle radiologique." In Journées Francophones d'Hépato-Gastroentérologie et d'Oncologie Digestive (JFHOD). Georg Thieme Verlag KG, 2019. http://dx.doi.org/10.1055/s-0039-1680986.
2
Xiaoxia, Wang, Li Zhuoran, Zhang Liying, You Wei, Liu Song, Mi Aijun, Mao Yawei, and Gao Guiling. "Analysis of Primary Coolant Corrosion Product Effect on Solid Waste Source Term." In 2017 25th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icone25-66945.
Анотація:
Corrosion product in the primary coolant is formed mainly by structure material corrosion and activated corrosion product. Under normal condition, source term of corrosion product maintains at a low level while its radioactive concentration reaches a peak value after the primary is injected with hydrogen peroxide during shutdown oxygenation operation. Following the procedure of corrosion product elimination, analysis has been made on effect which accumulated corrosion product exerts on RCV pre-filter and mixed bed demineralizer. Different primary coolant source terms and the cold shutdown peak value of corrosion product have been considered in the analysis. Under the assumption that dissolved and particle dissolved product has a fixed ratio of 1:1, the surface dose rate of RCV pre-filter varies as the different primary coolant varies. Nuclides proportion has been listed and charted based on the calculation. If cold shutdown condition has been taken in primary coolant source term calculation, then the RCV pre-filter surface dose rate will reach 345Sv/h; If primary coolant design value has been taken in source term calculation, then the RCV pre-filter surface dose rate will reach 42.2Sv/h; If 1/3 primary coolant design value has been taken in source term calculation, then the RCV pre-filter surface dose rate will reach 14.1Sv/h. For the waste resin in RCV mixed bed demineralizer, the corrosion product leaves a small contribution (less than 5%) if the cold shutdown is not considered in primary coolant source term calculation; and a contribution of over 90% if the cold shutdown is considered. The analysis provides a radiation safety analysis basis for NPP solid waste.
3
Pritrsky, Jozef, Miroslav Brodnan, and Vladimir Necas. "Conditional Release of Steel From Decommissioning in a Form of Reinforced Concrete." In ASME 2011 14th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2011. http://dx.doi.org/10.1115/icem2011-59058.
Анотація:
The paper deals with the conditional release of low-level radioactive steel from decommissioning in a form of reinforced concrete. The main goal was to determine limits for radionuclides concentration and calculate the annual dose for a member of a critical group of public, which should not exceed 10 μSv/year (according to IAEA Safety Guide RS-G-1.7). Corrosion is the principle mechanism of radionuclides release in this case; therefore effort was devoted to assess the time-dependent rate of steel reinforcement corrosion. It was assumed, that concrete is initially highly alkaline (with pH of 12 to 13) because of hydration products such as calcium hydroxide, which keeps the steel surface passive and protected from corrosion. However, carbonic acid resulting from carbon dioxide and water in the atmosphere can react with these products to produce calcium carbonate. This process is referred to as a “carbonation”, and leads after a period of time to significant reduction of the alkalinity (to pH as low as 8.5) followed by destruction of passive layer and starting corrosion of the embedded steel. The analytical principles and a set of input data have been implemented into a mathematical model developed by means of GoldSim software. The paper presents the results of mathematical simulation of corrosion process, which are compared with real measured values.
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Obeyesekere, Nihal U., Jonathan J. Wylde, Thusitha Wickramarachchi, and Lucious Kemp. "Formulation of High-Performance Corrosion Inhibitors in the 21St Century: Robotic High Throughput Experimentation and Design of Experiments." In SPE International Conference on Oilfield Chemistry. SPE, 2021. http://dx.doi.org/10.2118/204353-ms.
Анотація:
Abstract Critical micelle concentration (CMC) is a known indicator for surfactants such as corrosion inhibitors’ ability to partition to water from two phase systems such as oil and water. Most corrosion inhibitors are surface active. At critical micelle concentration, the chemical is partitioned to water from the interface, physisorption on metallic surfaces and forms a physical barrier between steel and corrosive water. This protective barrier thus prevents corrosion initiating on the metal surface. When the applied chemical concentration is equal or higher than the CMC, the surfactant is partitioned to aqueous phase from the oil-water interface. This would lead to higher chemical availability of the inhibitor in water, preventing corrosion. Therefore, it was suggested that CMC can be used as an indicator to optimal chemical dose for corrosion control1-5. The lower the CMC of a corrosion inhibitor product, the better is this chemical for corrosion control as the availability of the chemical in the aqueous phase increases. This can achieve corrosion control with lesser amount of corrosion inhibitor product. Thus, increasing the performance of corrosion inhibitor product. In this work, the physical property, CMC, was used as an indicator to differentiate corrosion inhibitor performance. A vast array of corrosion inhibitor formulations was achieved by combinatorial chemical methods using Design of Experiment (DoE) methodologies and these arrays of chemical formulations were screened by utilizing high throughput screening (HTE)6-8, using CMC as the selection guide. To validate the concept, a known corrosion inhibitor formulation (Inhibitor Abz) was selected to optimize its efficacy. This formula contains several active ingredients and a solvent package. Three raw materials of this formulation were selected and varied in combinatorial fashion, keeping the solvents and other raw materials constant9. These three raw materials were blended in a random but in a controled manner utizing DoE and using combinatorial techniques. Instead of rapidly blending a large amount of formulations using robotics, the design of experiment (DoE) methods were utilized to constrain the number of blends. When attempting to discover the important factors, DoE gives a powerful suite of statistical methodologies10. In this work, Design Expert software utilizes DoE methods and this prediction model was used to explore a desired design space. The more relevant (not entirely random) formulations were generated by DoE methods, using Design Expert software that can effectively explore a desired design space. The Design of Experiment software mathematically analyzes the space in which fundamental properties are being measured. The development of an equally robust prescreening analysis was also developed. After blending a vast array of formulations by using automated workstation, these products were screened for CMC by utilizing an automated surface tension workstation. Several formulations with lower CMCs than the reference product (Inhibitor Abz) were discovered and identified for further study. The selected corrosion inhibitor formulations were blended in larger scales. The efficacy of these products was tested by classical laboratory testing methods such as rotating cylinder electrode (RCE) and rotating cage autoclave (RCA) to determine their performance as anti-corrosion agents. As the focus of this project was to optimize the corrosion Inhibitor Abz, this chemical was used as the reference product throughout of this work. The testing indicated that several new corrosion inhibitor formulations discovered from this work outperformed the original blend, thus validating the proof of concept.
5
McKinnon, Mikal A., Judith M. Cuta, and Urban P. Jenquin. "Effect of Loading Pattern on Thermal and Shielding Performance of a Spent Fuel Cask." In ASME 2001 8th International Conference on Radioactive Waste Management and Environmental Remediation. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/icem2001-1216.
Анотація:
Abstract As part of a cooperative program, the United States Department of Energy (DOE) has supported analyses to determine the effect of cask loading on the thermal and shielding performance of a cask containing spent nuclear fuel. Two considerations that must be addressed in licensing spent fuel storage casks are peak fuel temperature and cask surface dose rate. Generally, storage systems are approved for uniform loading of the cask with design basis fuel. The storage system design basis typically specifies maximum assembly enrichment, maximum burnup, and minimum cooling times for the design basis fuel. Some casks specify an enrichment/burnup table. These conditions set the maximum decay heat loads and maximum radioactive source terms for the design. Supportive analysis using conservative assumptions is then used to demonstrate that acceptable fuel storage temperatures and cask dose rates are maintained. This study analyzes the effect of non.-uniform load patterns on peak fuel cladding temperatures and cask surface dose rates using previously validated analytical methods. The study was performed using a spent fuel storage cask that was designed to hold 24 spent fuel assemblies with a decay heat load of 24 kW. The cask was assumed to have a forged steel body with an overall length of 5.0 m and a diameter of 2.3 m. The body was assumed to be surrounded by a resin layer for neutron shielding and a steel outer shell. The fuel was selected to have cooling times of 3.5 to 10 years and burnups of 20 to 60 GWd/MTU to bound the expected range of burnup for most of the fuel to be discharged from boiling water and pressurized water reactors from the mid-1970s through 2020. Three radial power distributions were considered in the study: uniform loading, hotter assemblies in the center of the cask, and hotter assemblies near the wall of the cask. Each load pattern resulted in a total decay heat output of 24 kW from the cask. Seventeen different load patterns were selected, and the thermal analysis was repeated for three backfill gases: helium, nitrogen, and vacuum. For a given decay heat load in the cask, loading assemblies with higher decay heat output around the outside of the cask results in lower peak fuel cladding temperatures than loading hotter assemblies in the center of the cask. Several of the load patterns resulted in a peak cladding temperature that was lower than for a uniformly loaded cask. For a helium backfill with an optimum load pattern in the cask (hot assemblies near the basket wall), the peak fuel clad temperature was 17°C lower than a uniformly loaded cask. Using the same assemblies from the optimum load pattern but reversing the load pattern so the hot assemblies are moved to the inside of the cask., increased the peak fuel clad temperatures by 35°C for a helium backfill. This is 18°C greater than for a uniform load pattern. Seven source terms were selected to provide the thermal output used in the thermal analysis. Source term calculations were completed using fuel burnups of 20 to 60 GWd/MTU and enrichments of 2.4 to 4.8%. A constant power density of 32 MW/MTU was used for all irradiation calculations. Cooling times were selected to provide the decay heat values used in the thermal analysis. Photon dose rates are dominated by the cobalt-60 in the bottom-end fittings, top-end fittings, and plenum and are proportional to fuel burnup. For short cooling times, photon dose rates on the side of the cask are somewhat higher due to short-lived fission products. Cask loadings with high decay heat assemblies near the periphery exhibit increased photon dose rates on the side surface and top and bottom surfaces away from the centerline. Near the centerline, on the top and bottom of the cask, the dose rates are reduced substantially. Neutron dose rates increase exponentially with burnup and are nearly independent of cooling time. Cask loadings with high decay heat assemblies impact the neutron dose rates minimally. The peak dose rates (neutron plus photon) for the short-cooled, higher-burnup fuel loaded around the outside of the cask’s basket are generally less than for a uniform loading of longer-cooled, higher-burnup spent fuel.
6
Obeyesekere, Nihal U., and Jonathan J. Wylde. "Development of New Corrosion Inhibitors Using Robotics with High Throughput Experimentation Methods." In Abu Dhabi International Petroleum Exhibition & Conference. SPE, 2021. http://dx.doi.org/10.2118/207336-ms.
Анотація:
Abstract Critical micelle concentration (CMC) is a known indicator for surfactants such as corrosion inhibitors ability to partition from two phase systems such as oil and water. Most corrosion inhibitors are surface active and at critical micelle concentration, the chemical is partitioned to water, physadsorb on metallic surfaces and form a physical barrier between steel and water. This protective barrier thus prevents corrosion from taking place on the metal surface When the applied chemical concentration is equal or higher than the CMC, the chemical is available in aqueous phase, thus preventing corrosion. Therefore, it was suggested that CMC can be used as an indicator of optimal chemical dose for corrosion control1. The lower the CMC of a corrosion inhibitor product, the better is this chemical for corrosion control as the availability of the chemical in the aqueous phase increase and therefore, can achieve corrosion control with less amount of chemical. In this work, this physical property (CMC) was used as an indicator to differentiate corrosion inhibitor performance. The corrosion inhibitor formulations were built out by using combinatorial chemical methods and the arrays of chemical formulations were screened by utilizing high throughput robotics 2-4, using CMC as the selection guide. To validate the concept, several known corrosion inhibitor formulas were selected to optimize their efficacy. Each formula contained several active ingredients and a solvent package. These raw materials were blended in random but in a control, manner using combinatorial methodologies. Instead of rapidly blending a large number of formulations using robotics, the design of control (DOE) methods were utilized to constrain the number of blends. Once the formulations were generated by DOE method, using Design Expert software that can effectively explore a desired space. The development of an equally robust prescreening analysis was also developed. This was done by using the measurements of CMC with a high-throughput screening methodology. After formulation of a vast array of formulation by using Design Expert software, the products were screened for by CMC using automated surface tension workstation. Several formulations with lower CMC than the reference products were selected. The selected corrosion inhibitor formulations were identified and blended in larger scales. The efficacy of these products was tested by classical laboratory testing methods such as rotating cylinder electrode (RCE) and rotating cage autoclave (RCA) to determine their performance as anti-corrosion agents. These tests were performed against the original reference corrosion inhibitor. The testing indicated that several corrosion inhibitor formulations outperform the original blend thus validating the proof of concept.
7
Reistad, Ole, Frits Steenhuisen, O̸ystein B. Dick, Gisle Grepstad, Styrkaar Hustveit, and Ingar Amundsen. "Site Survey of Former Naval Base in Andreyev Bay, Northwest-Russia: Radiation Levels and Radionuclide Concentrations On and Below the Surface Level." In The 11th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2007. http://dx.doi.org/10.1115/icem2007-7148.
Анотація:
This paper presents the main results of the program to examine radiation levels and radionuclide concentrations on and below the surface level at the former Russian naval base in Andreyev Bay, Murmansk County. Presently, this base represents an exceptional case regarding future remediation and cleanup operations due to the accident risk (∼ max. fuel inventory of 100 submarine cores) and degree of contamination (over 25 years with continuous release — still ongoing — of radionuclides into the terrestrial and marine environment). The first part of the survey consists of about 1030 measurement points established as a grid with 10 m and 5 m mesh size for the measurement of dose rate in two heights above the ground level (0.1 m, 1 m), radionuclide concentrations, drilling of 50 boreholes for further examination of the radionuclide releases on site and the establishment of a 1:500 map of the area. These surveys were completed 2002–04. The results for dose rate measurements taken 1 m above the ground level varies between background levels and 3 mSv/h. Additional measurements were completed around the main building structures at the site and as part of a geological survey of the site. The activity concentration levels for Cs-137 and Sr-90 were measured in 250 points being part of the same measurement grid as above. The results for both isotopes range from normal fallout levels from atmospheric nuclear weapons testing to above 1 MBq/kg. The main conclusion is that continuous releases of fission products from spent nuclear fuel and fuel residues in defect storage pools have, together with inadequate storage facilities for large amounts of solid radioactive waste, led to heavy contamination of fission products in large areas. The 1:500 map is not public accessible. Thus, the second part of the survey was to analyse and document the results in adequate maps. These maps, geo-referenced to the UTM WGS84 system, have been established on the basis of commercial available satellite images from 2004 and show the measurement grid and results for radiation and activity levels in addition to coastline contour and selected infrastructure elements.
8
Bath, Adrian, Guido Deissmann, and Stephan Jefferis. "Radioactive Contamination of Concrete: Uptake and Release of Radionuclides." In ASME 2003 9th International Conference on Radioactive Waste Management and Environmental Remediation. ASMEDC, 2003. http://dx.doi.org/10.1115/icem2003-4814.
Анотація:
Concrete in nuclear installations may become contaminated by various radionuclides. Consequently, decommissioning and dismantling produce considerable quantities of potentially contaminated materials that must be managed safely and cost-effectively. In this paper we present preliminary results from a research project that aims to improve knowledge about release behaviour of radionuclides from contaminated concrete, and that proposes a scientific approach to calculating the source term for radiological dose assessment for the various management options (e.g. direct reuse, recycling, disposal of rubble). The first step is to consider which nuclides are likely to have contaminated concrete, where they might be located in concrete, and the extent to which they are chemically bound to concrete constituents. Relevant radionuclides include 60Co, 63Ni, 90Sr, 137Cs, 129I, U, Pu, Am and other actinide elements. Some nuclides are likely to be bound in specific solid phases and others are sorbed to greater or lesser degrees. The proposed modelling of releases from concrete takes into account the chemical behaviour (speciation, sorption and solubility) of the individual radionuclide contaminants and their binding to concrete phases. Other important factors that will influence release are mechanical and chemical condition of concrete, including cracking, carbonation, sulfate attack and degree of water saturation. Model calculations illustrate the potential release processes of desorption-diffusion, leaching (shrinking core model) and dissolution of discrete solid phases. For example, a scoping calculation suggests that 50-year old concrete may be contaminated with 129I to about 1 cm depth from the surface or more if the concrete is degraded, and that subsequent release will occur slowly by diffusion. Strongly sorbed or particulate nuclides such as Pu are likely to remain at the surface. Predicting the behaviour of some nuclides (e.g. Ni, U) is more uncertain because of uncertainty in the key parameters and their dependence on the local chemical conditions. Release models and source terms have been developed as the starting point for (i) the modelling of radiological consequences (i.e. dose assessments) of disposal options for building materials from nuclear installations and the optimisation of the disposal process (i.e. selection of cost-effective and reasonable disposal options), and (ii) the assessment of recycling/reuse options of slightly contaminated materials in order to reduce the amount of waste for disposal.
9
Domae, Masafumi, Kosho Hojo, and Wataru Sugino. "Corrosion Behavior of Zircaloy-4 in Methanol Solution at 320 °C Under Gamma-Irradiation." In 2013 21st International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icone21-15309.
Анотація:
It has been pointed out that high concentration dissolved hydrogen is one of the important factors of PWSCC (primary water stress corrosion cracking) in the primary systems of pressurized water reactors. Application of a substitution for hydrogen may be a fundamental countermeasure of PWSCC. The authors are developing a new water chemistry technology of a hydrogen alternative to suppress PWSCC. In the present paper, corrosion tests of Zircaloy-4 were performed in deaerated 5 mmol dm−3 methanol solution at 320 °C in the absence and presence of gamma-irradiation. The nominal absorbed dose of the test water was 100 kGy. After the immersion tests, the specimens were analyzed. Weight gain per unit surface area, thickness of oxide film and hydrogen storage were measured. In addition, Raman spectroscopy was carried out, to investigate possible deposition of organic compounds on surface of the specimens. The corrosion behavior of Zircaloy-4 without irradiation agreed with literature data. It was concluded that the presence of methanol did not affect the corrosion behavior of Zircaloy-4. The corrosion behavior of Zircaloy-4 hardly depended on 100 kGy gamma-irradiation. On the Raman spectra of the specimens after the immersion tests, the Raman peaks ascribed to polyethylene or graphite were not found. The deposit of decomposition products of methanol would be negligible if any. It seems that polymerization is not the major process in thermal decomposition and radiolysis of methanol, but methanol decomposes into CO2 or carboxylic acids.
10
Prokopovich, Polina, Stephanos Theodossiades, Homer Rahnejat, and Darren Hodson. "Nano- and Component Level Friction of Rubber Seals in Dispensing Devices." In ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/detc2009-86035.
Анотація:
In many drug dispensing devices, such as syringes and inhalers, a rubber ring is used as a seal. During device actuation the seal is subjected to friction which in turn causes it to deform. This can lead to suboptimal performance of the device and as a consequence variability in the delivered dose. Seal friction is complex, arising from adhesion of rubber in contact with a moving counterface, viscous action of a thin film of entrained fluid into the contact and ploughing of seal asperities. Therefore, the first step in the understanding of the conjunctional behaviour of rubber seals is the fundamental study of these friction mechanisms. A developed model can then be validated against measurements, prior to its use in a multi-body dynamic model of the inhaler valve to predict product performance, robustness and variability due to manufacturing tolerances. This paper undertakes two distinct studies. Firstly, a friction model for the rough elastomeric material, typically used for valve seals is developed. The model is then validated against measurements in nano-scale. Friction data is presented for nitrile rubber, using a silicon nitride AFM tip for nano-scale interactions. The validation is then extended to macro-scale motion of an instrumented trolley, incorporating an elastomeric surface sliding on a polymeric counterface. These tests are carried out for polybutylene terephthalate (PBT). Secondly, the validated friction model is used in an elastomeric seal model in-situ within the valve and in contact with a polymeric stem surface and subject to both global fittment deformation and canister pressure. Reasonable agreement is found between the measurements and model predictions for the nano-scale coefficient of friction of rubber against silicon nitride. Similarly, good agreement has been obtained for the mean coefficient of friction of rubber against PBT. In addition, the mechanism of adhesion between contacting surfaces of gasket and stem is taken into account.