Academic literature on the topic 'Fluorace'
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 'Fluorace.'
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 "Fluorace"
1
Essebbahi, Issam, Chadia Ouazzani, Abdallah Moustaghfir, Abdallah Dami, and Lhoussine Balouch. "Analyses physicochimiques de différents thés commerciaux et risque de l’excès de fluor chez la population au Maroc." International Journal of Biological and Chemical Sciences 14, no. 4 (August 17, 2020): 1203–13. http://dx.doi.org/10.4314/ijbcs.v14i4.4.
Full textAbstract:
Sous la forme de fluorure, le fluor entre dans la constitution des tissus durs comme les dents, les os et les cartilages. L’apport excessif en fluor pendant plusieurs mois ou plusieurs années lors de la période de formation des dents peut provoquer la fluorose. Certains aliments habituellement consommés au Maroc sont riches en fluor. Les traitements industriels de transformation, préparation et conservation mettent à la disposition du consommateur des aliments de coût moins chers et de compositions variables qui peuvent être nuisibles à la santé buccale. L’étude des qualités physicochimiques de différentes sources alimentaires de fluor constituées de différents thés noirs, verts, d’eaux de puits consommés par la population marocaine permet de dévoiler la corrélation entre la consommation des aliments riches en fluor et l’apparition de la fluorose dentaire. Différentes de tisanes de granules de 12 thés verts et noirs ont été préparés selon la variation de la durée d’infusion et du mode d’ébullition. Les teneurs de fluor, calcium, chlorures ont été déterminées par les méthodes spectrophotométriques sur 17 échantillons de thés verts et noirs commercialisés, thés glacés, thés de distributeur automatique, thé de buvette, thé de préparation familiale. La teneur en fluor a été déterminée sur 3 échantillons des eaux de puits, 3 eaux d’assainissement urbain de la région de Skhirat Témara afin de déterminer l’apport de fluor contenu dans l’eau de préparation des tisanes. Les analyses physicochimiques révèlent des taux de calcium de 14 à 60 mg/l, chlorures (14 à 75 mg/l) et de fluor (0,93 à 2,7 mg/l) chez les différents thés verts et noirs étudiés, thé de distributeur automatique, thé de buvette et familiale. Les analyses des taux de fluor de 3 échantillons de thés verts marquent Sultan, Menara, Dahmis et un thé noir Earl Grey révèlent des valeurs supérieures aux normes recommandées pour les enfants et les adultes. Le taux de fluor du thé de la buvette est supérieur à celui du thé de distributeur automatique et de préparation familiale. Ces résultats permettent de prévenir la population face au risque d’atteinte de la fluorose dentaire, en limitant la quantité de fluor ingérée par les aliments consommés. Les analyses des niveaux de fluor de tous les types de produits de thés et des eaux de préparation des thés permettront de disposer de mesures de protection de consommation excessive de fluor.Mots clés : Fluor, aliments, thés, Maroc, excès, risques, fluorose
English Title: Physicochemical analyzes of different commercial teas and risk of excess fluorine in the population in Morocco
In the form of fluoride, fluorine enters into the constitution of hard tissues such as teeth, bones and cartilage. Excessive intake of fluoride for several months or years during the period of tooth formation can cause fluorosis. Some foods usually consumed in Morocco are rich in fluorine. The industrial treatments of preparation, transformations make available to the consumer cheaper foods of variable composition which can be harmful to oral health. The study of physicochemical qualities of different food sources of fluorine consisting of different black teas, green teas and well water consumed by the population reveals a correlation between the consumption of foods rich in fluorine and the appearance of dental fluorosis. Different preparations of herbal teas from granules of 12 green and black teas were prepared according the variation of the infusion time, the boiling mode. The contents of fluorine, calcium, chlorides were determined by spectrophotometric methods on 17 samples of green and black teas from vending machines, refreshment tea, family preparation tea. The fluorine content was determined on 3 samples of well water, 3 urban sanitation water from the Skhirat Temara region in order to determine the fluorine content contained in the water for preparing herbal teas. The physicochemical analyzes reveal levels of Calcium (14 to 60 mg/l), Chlorides (14 to 75 mg/l) and fluorine (0.93 to 2.7 mg/l) in the various green and black teas studied, tea vending machine, refreshment and family tea. The analyzes of the fluoride levels of three samples of marketed green teas Sultan, Menara, Dahmis and an Earl Gray black tea reveal values higher than the recommended standards for children’s and adults. The fluoride level of the tea in the refreshment room is higher than that of the vending machine and family preparation tea. These results make it possible to warn the population facing the risk of developing dental fluorosis, by limiting the amount of fluorine ingested by the consumed food. Analyzes of fluoride levels of all types of tea products and tea preparation waters will provide measures to protect against excessive fluoride consumption.
Keywords: Fluorine, foods, teas, Morocco, excess, risk, fluorosis.
2
Dibal, H. U., W. N. Dajilak, I. C. Lekmang, L. W. Nimze, and E. Y. Yenne. "Seasonal Variation in Fluoride Content in Groundwaters of Langtang Area, Northcentral Nigeria." Contemporary Trends in Geoscience 6, no. 1 (June 1, 2017): 11–27. http://dx.doi.org/10.1515/ctg-2017-0002.
Full textAbstract:
Abstract Thirty groundwater samples were collected at the peak of the rainy season and analysed for fluoride and other cations and anions in drinking water sources of Langtang area. For comparative purposes, thirty seven groundwater samples were collected in the dry season. The aim of the study was to determine variation in fluoride content with respect to the seasons. Fluoride in water was determined by the Ion Selective Electrode (ISE) and the cations by the Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The anion (sulphate) was determined by Multi – Ion Colorimeter, bicarbonate and chloride by titration method. In addition fluorine content in aquifer materials from a borehole section were determined by Fusion method. The two seasons show variation in content of fluoride in groundwater. Fluoride content in groundwater is higher in the dry season ranging from 0.13 – 10.3 mg/l compared to the 0.06 – 4.60 mg/l values in the rainy season. Content of fluorine (0.01 wt %) in the aquifer materials (sands) is low from depth of 0 to 7.95 m. However, fluorine content increases with depth, from 7.95 to 10.60 m with concentration of 0.04 wt %, 0.05 wt % from 10.60 to 13.25m, and 0.07 wt % from 13.25 to 15.70 m, the content of fluorine however, decreased at depth 15.70 to18.55m with concentration of 0.02 wt % even with fluorite mineral in the aquifer material at this depth. Dilution of fluoride ion as a result of rain input which recharges the aquifer may be the main reason for lower values recorded in the rainy season. Over fifty and sixty percent of waters in both dry and rainy season have fluoride concentration above the WHO upper limit of 1.5 mg/l. Consumption of these elevated values of fluoride in groundwater of the study area, clearly manifests as symptoms of dental fluorosis.
3
Karpukhina, Natalia, Robert V. Law, and Robert G. Hill. "Solid State NMR Study of Calcium Fluoroaluminosilicate Glasses." Advanced Materials Research 39-40 (April 2008): 25–30. http://dx.doi.org/10.4028/www.scientific.net/amr.39-40.25.
Full textAbstract:
Fluorine containing calcium aluminosilicate glasses are widely used for a number of technological applications including dental cements, mould fluxes in steel making and in a variety of glass-ceramic systems. Despite of their importance these systems remain quite poorly understood with respect to their composition. To address this question a glass composition corresponding to the equimolar binary system anorthite−fluorite (Ca2Al2Si2O8−CaF2) was chosen as a base point for two series of compositions. One of the series is designed on the anorthite stoichiometry and considered as classically charge balanced. Another series starts from the fluorine free composition of the anorthite−lime (Ca2Al2Si2O8−CaO) stoichiometry and, therefore, is characterized by a disrupted network with at least one non-bridging oxygen (NBO) attached to silicon. A multinuclear 19F, 27Al, 29Si solid state NMR study of the glasses was undertaken. It is shown that in both series fluorine is predominantly coordinated by calcium, F−Ca(n), and in addition interacts with aluminium forming Al−F−Ca(n) complexes, where n denotes the number of first neighbouring calcium cations. Small amounts of high coordinated aluminium grows with increasing fluoride content in both glass series. However, the high coordinated aluminium may not be solely due to the formation of the Al−F−Ca(n) complexes. Glasses of the first series displayed systematic upfield shift of 29Si NMR resonance while substituting fluoride for oxide, starting from the fluorine free composition. This upfield shift is interpreted as the lack of cations in the network, due to formation of the F−Ca(n), which drives silicon network to polymerize toward a higher Qn structure. Contrary to the first series, the 29Si NMR resonance remains constant for fluorine containing compositions of the second series but differs downfield from the initial anorthite glass. The latter is explained by the excess of cations in the network due to addition of the fluorite resulting in formation of NBO on the silicon. Binding of fluorine with silicon is considered negligible in these systems. Thus, fluorine and calcium both define the degree of network polymerization and are considered as a cause for the changes in silicon and aluminium networks.
4
Сорокин, Н. И., and Б. П. Соболев. "Собственная фтор-ионная проводимость кристаллических матриц фторидных супериоников: BaF-=SUB=-2-=/SUB=- (тип флюорита) и LaF-=SUB=-3-=/SUB=- (тип тисонита)." Физика твердого тела 61, no. 1 (2019): 53. http://dx.doi.org/10.21883/ftt.2019.01.46893.181.
Full textAbstract:
AbstractThe intrinsic fluorine-ion conductivity σ_lat of BaF_2 (CaF_2 fluorite type) and LaF_3 (tysonite type) crystals is studied by the impedance spectroscopy method. These compounds represent two major structural types taken as the basis to form the best nonstoichiometric fluorine-conducting solid electrolytes. The conductivity σ_lat caused by thermally activated defects is manifested in the field of high temperatures, where conductometric measurements are complicated by pyrohydrolysis. The experiments carried out in inert atmosphere with application of the impedance method have for the first time produced the reliable values of σ_lat of fluoride crystals in conditions of suppression of pyrohydrolysis (BaF_2) or partial pyrohydrolysis (LaF_3). Values of the σ_lat at 773 K for BaF_2 and LaF_3 crystals grown from melt by the Bridgman method using the vacuum technology are 2.2 × 10^–5 and 8.5 × 10^–3 S/cm differing by a factor of ~400. The tysonite structural type has been proved feasible for making high-conductivity solid fluoride electrolytes based on the analysis of energy characteristics of formation and migration of anionic defects.
5
CHEN, Shi Yi, and Shou Ting Zhang. "Research on the Utilization and Industry Development Strategies of Fluorite Resources in China's Fluorine Chemical Industry." Advanced Materials Research 581-582 (October 2012): 142–45. http://dx.doi.org/10.4028/www.scientific.net/amr.581-582.142.
Full textAbstract:
This paper introduced fluorite resource profiles on the basis of elaborated China fluorite resource utilization status, focusing on analysis of fluorite in the fluorine chemical industry, discusses the problems of our country in the fluorine chemical industry development and firefly stone rational use of resources and the sustainable development of China's fluorine chemical industry recommendations.
6
Fedorchuk, Yu M., V. V. Matvienko, D. V. Naryzhny, and A. S. Rybin. "Resource- and Energy-Saving Method for Obtaining Hydrogen Fluoride and Hydrite Fluoride." Voprosy sovremennoj nauki i praktiki. Universitet imeni V.I. Vernadskogo, no. 3(77) (2020): 032–39. http://dx.doi.org/10.17277/voprosy.2020.03.pp.032-039.
Full textAbstract:
An ecologically and economically effective technical solution has been developed for the production of hydrogen fluoride and fluorine hydrite by using fluorosulfonic acid in the decomposition technology of fluorspar. The stages of the technology of obtaining hydrogen fluoride and fluorine hydrite are shown: obtaining fluorosulfonic acid itself, decomposition of calcium fluoride with fluorosulfonic acid and hydrolysis of calcium fluorosulfonate with water vapor to form fluorosulfonic acid, recycled, hydrogen fluoride and fluorine hydrite. Experimental data have shown the promise of this technology.
7
Liu, Hanyong, Qiao Zhu, and Xiaozhi Yang. "Electrical Conductivity of Fluorite and Fluorine Conduction." Minerals 9, no. 2 (January 27, 2019): 72. http://dx.doi.org/10.3390/min9020072.
Full textAbstract:
Fluorine is a species commonly present in many minerals in the Earth’s interior, with a concentration ranging from a few ppm to more than 10 wt. %. Recent experimental studies on fluorine-bearing silicate minerals have proposed that fluorine might be an important charge carrier for electrical conduction of Earth materials at elevated conditions, but the results are somewhat ambiguous. In this investigation, the electrical conductivity of gem-quality natural single crystal fluorite, a simple bi-elemental (Ca and F) mineral, has been determined at 1 GPa and 200–650 °C in two replication runs, by a Solartron-1260 Impedance/Gain Phase analyzer in an end-loaded piston-cylinder apparatus. The sample composition remained unchanged after the runs. The conductivity data are reproducible between different runs and between heating-cooling cycles of each run. The conductivity (σ) increases with increasing temperature, and can be described by the Arrhenius law, σ = 10^(5.34 ± 0.07)·exp[−(130 ± 1, kJ/mol)/(RT)], where R is the gas constant and T is the temperature. According to the equation, the conductivity reaches ~0.01 S/m at 650 °C. This elevated conductivity is strong evidence that fluorine is important in charge transport. The simple construction of this mineral indicates that the electrical conduction is dominated by fluoride (F−). Therefore, fluorine is potentially an important charge carrier in influencing the electrical property of Fluorine-bearing Earth materials.
8
SCHUPPLI, P. A. "TOTAL FLUORINE IN CSSC REFERENCE SOIL SAMPLES." Canadian Journal of Soil Science 65, no. 3 (August 1, 1985): 605–7. http://dx.doi.org/10.4141/cjss85-065.
Full textAbstract:
Total fluorine was measured in a variety of Canadian soils using the lithium metaborate-nitric acid solution technique in conjunction with the fluoride electrode. Total fluorine ranged from 90 to 1000 mg∙kg−1. Key words: Soil fluorine analysis, fluoride electrode, CSSC reference soil samples
9
Shevelev, G. A., L. I. Vasilenko, O. M. Pakhorukova, O. N. Kosheleva, T. S. Turmagambetov, E. N. Kamenskaya, N. G. Kamensky, and A. A. Dzyuba. "Emission determination of fluorine using «Grand-Potok» complex with sample injection into dc arc by spill-injection method." Industrial laboratory. Diagnostics of materials 85, no. 1II) (February 15, 2019): 45–49. http://dx.doi.org/10.26896/1028-6861-2019-85-1-ii-45-49.
Full textAbstract:
An additional photodetector array BLPP-369 was installed on a «Grand-Potok» complex for rapid atomic-emission determination of the fluorine concentration in fluorite samples. Introduction of fluorite samples was carried out using the spill-injection method simultaneously with high pure calcium oxide introduction using the second conveyor belt. The use of an additional photodetector array with a spectral range of 528 – 536 nm provides the possibility of expanding the spectrum of CaF molecular lines with the intensity sufficient for determination of fluorine concentrations in fluorite samples. A calibration curve for fluorine determination in a concentration range of 0.12 – 47.63% was plotted using measurement results for 200 fluorite samples. Integration of the additional photodetector array provided increased detection limit for the mass fractions of fluorine up to the maximum possible concentrations in fluorite samples. The observed effect simplifies and speeds up the analysis in the absence of the necessity to dilute the sample, thus reducing the error of measurements. The results show that there is no need to introduce additional buffer mixtures (except CaO) and use reference lines to determine the fluorine concentration, which also simplifies the measurement procedure.
10
Komatsu, Hisanori, Katsushi Okuyama, Hiroko Yamamoto, Keisuke Yasuda, Masaharu Nomachi, and Yorihito Sugaya. "Tooth-bound fluoride uptake from fluoride-containing dental materials." International Journal of PIXE 23, no. 03n04 (January 2013): 127–34. http://dx.doi.org/10.1142/s0129083513410052.
Full textAbstract:
Whether fluorine penetrated from material completely incorporates into tooth mineral is a matter of debate, although it is well known that the fluoride from material penetrates directly into tooth structures. The purpose of this study is to determine tooth-bound fluoride uptake from fluoride-containing materials using PIGE/PIXE system at the Wakasa Wan Energy Research Center. Class V cavities in buccal surfaces of eighteen extracted human teeth were drilled and filled with six fluoride-containing materials. After being stored in distilled water for one year, a longitudinal section including materials was obtained from each tooth. Fluorine and calcium distribution of specimens were evaluated using PIGE/PIXE system. After evaluation, the specimens were immersed in 10 mL of 1M KOH solution and were agitated at room temperature for 24 h to remove a KOH soluble fluoride. The specimens were washed with 200 mL distilled water and left to dry. Again, to estimate tooth-bound fluorine (KOH-insoluble fluoride) uptake, the same portion of the specimens after KOH treatment were evaluated using PIGE/PIXE system. It was confirmed that fluorine penetrated from material partly incorporated into tooth mineral. This tooth-bound fluoride have the potential to prevent dental caries after loss of the bond between the filling material and tooth structure.
Dissertations / Theses on the topic "Fluorace"
1
Silva, Amanda Falcão da 1986. "Biodisponibilidade de fluoreto a partir de dentifrício contendo carbonato de cálcio ou sílica como abrasivo." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289529.
Full textAbstract:
Orientador: Livia Maria Andaló Tenuta.Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba.
Made available in DSpace on 2018-08-20T01:44:17Z (GMT). No. of bitstreams: 1 Silva_AmandaFalcaoda_M.pdf: 1498543 bytes, checksum: 27e089825c6e3d6a738cf8f3567dfa89 (MD5) Previous issue date: 2012
Resumo: Dentifrícios fluoretados tem sido considerados responsáveis pelo declínio de cárie ocorrido mundialmente, entretanto, são também considerados fatores de risco para fluorose dental. Todavia, não tem sido encontrada correlação entre a dose de ingestão de fluoreto (F) pelo dentifrício, na idade de risco para o desenvolvimento de fluorose e sua posterior prevalência. Uma das razões para esse achado é que a concentração total de F no dentifrício e não aquela biodisponível (fração solúvel que é absorvida) tem sido considerada no cálculo da dose de ingestão. Nesse contexto, dentifrícios fluoretados contendo carbonato de cálcio como abrasivo apresentam parte do F total indisponível para ser absorvido, ou seja, na forma insolúvel, que sofre aumento em função do tempo...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital
Abstract: Fluoride toothpastes are considered responsible for caries decline worldwide but they are also considered as risk factors for dental fluorosis. Nonetheless, there has been no correlation between fluoride (F) intake from toothpaste in the age of risk for developing fluorosis and its subsequent prevalence. One reason for this finding is that the total F concentration in toothpastes and not that bioavailable (soluble fraction which is absorbed) has been considered in calculation of the F dose ingested...Note: The complete abstract is available with the full electronic document
Mestrado
Cariologia
Mestre em Odontologia
2
Bostwick, Aaron A. "Impact on calcium fluoride reactivity and electronic structure of photon and electron stimulated fluorine desorption /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/9721.
Full text
3
Partey, Frederick Kenneh. "SOURCE OF FLUORINE AND PETROGENESIS OF THE RIO GRANDE RIFT TYPE BARITE-FLUORITE-GALENA DEPOSITS." Miami University / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=miami1092262697.
Full text
4
Mateus, Tavares Ana Raquel. "Etude de la précipitation de la fluorine en milieu alcalin et application à un procédé en réacteur à lit fluidisé." Thesis, Saint-Etienne, EMSE, 2013. http://www.theses.fr/2013EMSE0710/document.
Full textAbstract:
Le procédé adopté par COMURHEX pour le traitement des effluents très chargés en fluor est basé sur l’addition d’un composé alcalin Ca(OH)2 (portlandite) pour faire précipiter de la fluorine (CaF2). Mis en œuvre par le passé dans un décanteur le développement d’un nouveau procédé en lit fluidisé a été envisagé pour augmenter l’efficacité du traitement des effluents. Des essais concluants ont été réalisés sur une installation pilote qui ont démontré l’efficacité de la précipitation en lit fluidisé à assurer une réduction satisfaisante de la concentration du fluor. Cependant, les phénomènes mis en jeu dans le réacteur sont mal connus.Notre objectif principal est la maîtrise de la précipitation de la fluorine dans le réacteur à lit fluidisé ainsi qu’une meilleure compréhension des mécanismes mis en jeu. Pour ce faire, il a été nécessaire de reprendre l’étude thermodynamique du système KOH-portlandite-calcite-fluorine, de manière à étendre les données existantes aux fortes concentrations de KOH en solution. Un modèle thermodynamique capable de prédire la solubilité des solides en présence de variations de la concentration de la potasse et de la température du système a été établi.La deuxième partie du travail a été focalisée sur la compréhension des mécanismes mis en jeu pendant la formation de la fluorine. Les expériences réalisées au laboratoire ont conduit à l’obtention d’une fluorine issue d’une conversion de la portlandite. Ce mécanisme a été modélisé en considérant que le remplacement de la portlandite par la fluorine s’explique par un modèle à cœur rétrécissant contrôlé par la limitation diffusionnelle du fluorure dans la couche de fluorine formée. La dernière partie expérimentale de ce travail a été réalisée sur le pilote à lit fluidisé. Les expériences effectuées n’ont pas donné de résultats satisfaisants. Il n’a pas été possible de faire faire fonctionner le pilote de façon cohérente avec les objectifs de son dimensionnement. En particulier, compte-tenu de la très petite taille des particules, les débits de fonctionnement conduisent à l’envolement de celles-ci, mais pas à l’établissement de l’état fluidiséThe method used by COMURHEX for the treatment of fluorine-rich effluents relies on the addition of solid Ca(OH)2 (portlandite) to precipitate fluorite (CaF2) in strongly alkaline solutions. This method is effective in a settler, and the development of a new fluidized bed process has been proposed to increase its efficiency. Successful assays were conducted on a pilot scale and they demonstrated that precipitation in a fluidized bed reactor actually ensures a satisfactory defluorination. However, the phenomena involved remained poorly known, and the main goal of the present work was to elucidate the mechanisms, their kinetics, and to control the crystallization.Our first contribution is a thermodynamic reappraisal of the KOH–portlandite–calcite system that extends existing solubility data to higher KOH concentrations in solution and incorporates new solubility data for fluorite. The outcome is an aqueous speciation model (Pitzer type) accounting for the solids solubility as a function of the KOH concentration and the temperature, and allowing portlandite undersaturation and fluorine supersaturation to be evaluated in process solutions.Our second contribution focuses on the kinetics and the mechanisms involved during the formation of fluorite, using various mixing designs in batch reactors. Reaction rates are fast, except in experiments involving dilute reactants. Microprobe and granulometric data both indicate that much of the fluorine results from the conversion of the portlandite grains. A shrinking core model controlled by diffusive transfer of fluoride in the porous fluorite corona successfully fits the kinetics of fluorine uptake and the particle grain size.The last part of the experimental work was carried out on a small fluidized bed pilot. These experiments were poorly conclusive. The very small particle size and the large flow rates lead to particle blow off, but not to fluidization. As a consequence, the capacity of the fluidized bed to promote an increase of the particle grain size remains largely unknown
5
Dolejš, David. "Thermodynamics and phase equilibria of the silicate-fluoride-H₂O systems : implications for fluorine-bearing granites." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85066.
Full textAbstract:
The progressive enrichment in volatiles and light incompatible elements observed during upper-crustal differentiation of granitic and rhyolitic magmas leads to significant changes in melt physical-chemical properties and has important implications for ore deposition and volcanic devolatization. Thermodynamic calculations and experimental studies of melting equilibria in the Na 2O-K2O-Al2O3-SiO2-F 2O-1-H2O system are used to evaluate mineral stabilities, fluid compositions, the extent of fluoride-silicate liquid-liquid immiscibility, fluorine and water solubility limits and differentiation paths of natural fluorine-bearing silicic magmas. The interaction of fluorine with rock-forming aluminosilicates corresponds to progressive fluorination by the thermodynamic component F2O-1. Formation of fluorine-bearing minerals first occurs in peralkaline and silica-undersaturated systems that buffer fluorine concentrations at very low levels (villiaumite, fluorite). The highest concentrations of fluorine are achieved in peraluminous silica-oversaturated systems, saturated with fluorite or topaz. Thermodynamic models of fluorosilicate melts indicate clustering of silicate tetrahedra in the Na2O-SiO 2-F2O-1 system, whereas initial NaAl-F short-range order evolves into partial O-F disorder in the albite-cryolite system. Experiments performed at 520-1100°C and 0.1-100 MPa completely describe liquidus relations and differentiation paths of fluorine-bearing felsic magmas. Coordination differences and short-range order effects between [NaAl]-F, Na-F vs. Si-O lead to the fluoride-silicate liquid immiscibility, which extends from the silica-cryolite binary through the peralkaline albite-silica-cryolite ternary and closes in multicomponent, topaz-bearing systems owing to the destabilizing effect of increasing peraluminosity. Liquidus relations indicate that fluoride-silicate liquid-liquid immiscibility is inaccessible to quartz-feldspar-saturated granitic melt
6
Mamuse, Antony. "Fluoride contaminated drinking water in Gokwe District (NW Zimbabwe) : spatial distribution, lithostratigraphic controls and implications for human health /." Curtin University of Technology, Department of Applied Geology, 2003. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=15235.
Full textAbstract:
The supply of drinking water in Gokwe District (NW Zimbabwe) is almost entirely based on groundwater drawn from boreholes and open dug wells. In certain areas of the district, the occurrence of dental fluorosis has been linked to excessive fluoride in the water supplies. A high prevalence of dental fluorosis (about 62%) was previously recorded among school children in the district. The aim of this study was to determine relationships between the spatial distribution of fluoride content in drinking water supplies in Gokwe, and lateral and vertical geological variation. A total of 224 water samples were collected from 196 water sources in the study area (a further 18 water sources just outside the study area were also sampled). All the samples were analysed for fluoride in the field using the fluoride ion selective electrode method (FISE). One hundred and fifty nine duplicate samples were analysed for fluoride and common anions and cations using High Performance Ion Chromatography (HPIC) in the laboratory. Two main groups of computer programmes were employed: (1) Geographic Information System (ArcView® GIS) was used to store, analyse and display multiple layers of surface geologic and geographic information, and (2) a three-dimensional visualisation programme (Rockworks) was used to interpret and illustrate site stratigraphy based on borehole information. Results indicated that the fluoride content of drinking water in the study area ranges from 0 to 9.65 mg/L. Forty-seven water sources (24%) yielded water containing fluoride in excess of the World Health Organisation's (WHO) health limit of 1.5 mg/L F. Of the 47 high fluoride water sources, 43 were boreholes (pumped or artesian). The shallower water sources (dug wells, streams and dams) largely yielded low-fluoride water.The groundwater fluoride contamination is stratigraphically controlled and originates from carbonaceous material (carbonaceous shales, carbonaceous mudstones and coaly material) within the Lower Madumabisa and Middle Wankie Members of the Lower Karoo Group. It has been shown that in general the greater the proportion of carbonaceous material intersected by a borehole, the greater the fluoride concentration of the water. Probable mineral sources of fluoride within the carbonaceous material include fluorapatite, kaolinite and trona. Chemical parameters that appear to influence the concentration of dissolved F in the water supplies include total dissolved solids (TDS), NaCl and pH. In relatively low fluoride waters, F concentrations generally increase with TDS and NaCl concentrations, whereas the highest F concentrations are found in moderately alkaline (pH 7.8-9) waters. Based on ranges of fluoride concentration in drinking water, fluorosis-risk zones were identified and have been illustrated on a fluorosis-risk map. The zones are: No Risk Zone (0-1.5 mg/L F), Moderate Risk Zone (1.5-3.0 mg/L F), High Risk Zone (3.0-6.0 mg/L F) and the Very High Risk Zone (6.0-10.0 mg/L F). The map suggests that groundwater available to people occupying 3650 km z (60.8%) of the study area potentially contains excessive fluoride (F>1.5 mg/L), presaging the occurrence of dental fluorosis, skeletal fluorosis and crippling skeletal fluorosis in the area. Different strategies may be employed to ameliorate the fluoride problem in Gokwe.
These include sinking new boreholes to optimal depths and in appropriate locations, promoting the use of surface water and shallow groundwater, resettlement and defluoridation. However in order to fully understand the problem and to prescribe these or other solutions more comprehensively, multi-disciplinary studies may be required. Such studies may consider isotopic dating of water to investigate any relationships between fluoride concentration and residence time of water, geochemical analyses of rocks and soils, detailed fluorosis epidemiology studies and test-scale defluoridation investigations.
7
Catani, Danilo Bonadia. "Influencia do heterocontrole de fluor na ocorrencia de fluorose na dentição permanente." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289316.
Full textAbstract:
Orientadores: Jaime Aparecido Cury, Maria da Luz Rosario de SousaDissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
Made available in DSpace on 2018-08-08T13:12:46Z (GMT). No. of bitstreams: 1 Catani_DaniloBonadia_M.pdf: 554114 bytes, checksum: 2f2e38479e437aac4f9185d38e290266 (MD5) Previous issue date: 2006
Resumo: O objetivo geral deste estudo, composto por dois trabalhos, foi analisar as possíveis relações entre a exposição a níveis diferenciados de íon flúor na água de abastecimento público e a presença de fluorose dentária na dentição permanente, e analisar os possíveis fatores associados. No primeiro trabalho foi analisada a concentração de fluoreto em amostras de água enviadas de 07 cidades do estado de São Paulo, além de um município no Estado de Minas Gerais e outro no Ceará. As coletas das amostras de água foram realizadas no período de 1996 a 2002, sendo as mesmas avaliadas utilizando-se um analisador de íons (Orion 96-09 e analisador de íons EA-940 previamente calibrados com padrões contidos de 0,125 a 1,0 mg F/ml , com 1,0 ml de Tisab II, ou seja, Tisab II a 50%) acoplado a um eletrodo de flúor previamente calibrado. Num total de 2667 amostras no período analisado, observou-se que mais que 59,2% das amostras encontraram-se dentro dos padrões considerados ótimos (0,6?0,8 ppm F), sendo 6,3% das amostras com valores menores que 0,4 ppm F, 18,1% entre 0,4 a 0,6 ppm F,13,3% entre 0,8 a 1,0 ppm F e 3,1% com valores maiores que 1 ppm F. Pode-se concluir, portanto, que a maioria das amostras coletadas estavam no considerado nível ótimo (0,6?0,8 ppm F), contudo verifica-se que há dados e regiões que estão fora do padrão considerado ideal, sendo importante a manutenção do heterocontrole. O objetivo do segundo trabalho foi verificar a prevalência da fluorose dentária em escolares de 7 anos de idade residentes em dois municípios que se diferenciam quanto aos níveis ótimos de flúor na água de abastecimento público, e investigar possíveis fatores associados. A amostra deste estudo foi composta por 386 crianças de 7 anos de idade, nascidas no ano de 1997, matriculadas em escolas públicas e instituições privadas de ensino em municípios que realizaram heterocontrole de flúor na água de 1998 a 2002. A fluorose dental foi avaliada por meio do índice de Dean. Foram examinados os incisivos superiores permanentes, previamente secos e sob iluminação artificial com equipamento odontológico portátil. Considerou-se como presença de fluorose as formas: questionável, muito leve, leve, moderada e severa. Variáveis sócio-demográficas e questões sobre saúde bucal foram avaliadas com um questionário estruturado enviado aos pais/responsáveis. Os resultados mostraram que a prevalência de fluorose no município com níveis oscilantes de íon flúor foi de 31,40% e no município com níveis homogêneos de fluoretos 79,91%. Entretanto, em ambos os municípios, prevaleceu o grau "muito leve" de fluorose, portanto sem comprometimento estético. A prevalência de fluorose foi associada com o município com teores de flúor constante na água e com um único indicador sócio-econômico
Abstract: The general objective of this paper, based over two works, was to analyze possible relationships among different levels of fluoride ions in the public water supply and the presence of dental fluorosis in permanent teeth. Associated factors are also to be analyzed. At the first stage of the process, fluoride concentration present in water samples sent from 7 cities of São Paulo State, one city of Minas Gerais State and another from Ceará State were to be analyzed. All the water sample collections took place during the period of 1996 and 2002 and an ion analyzer was used in the process of evaluation (Orion 96-09 and a ion analyzer EA-940 previously gauged with patterns of 0.125 to 1.0 mg F/ml, with 1.0 ml of Tisab II, so, Tisab II at 50%) coupling to a fluoride electrode previously gauged as well. Over a total of 2667 samples collected in the mentioned period it was noted that more than 59.2% of them were found to contain patterns considered great (0.6-0.8 ppm F ), 6.3% of them with lower values than 0.4 ppm F; 18.1% of them between 0.4 to 0.6 ppm F; 13.3 % between 0.8 and 1.0 ppm and 3.1% with values larger than 1 ppm F. In view of the aforementioned results it is possible to concluded that the majority of collected samples were in the level range considered optimal (0.6-0.8 ppm F). However, it was possible to also verify that some of the results and regions are out of the considered ideal pattern implying that hetero-controlling maintenance is important. The objective of the second work was to evaluate the prevalence and correlates of dental fluorosis in school children aged 7 years living in two cities of São Paulo State, Brazil, with fluoridation of water supplies, with emphasis in the effects of external control of the fluoride levels. The study population comprised 386 children, all born in 1997 and enrolled in public and private schools from 2 municipalities had fluoride external control of the fluoride levels from 1998 to 2002. The upper permanent maxillary incisors were examined under artificial light and the aid of an air syringe. The Deanâ?¿s Index was utilized to identify dental fluorosis. In this study dental fluorosis were considered such as: questionable; very mild; mild; moderate and severe. Socio-demographics and dental history were assessed with a structured questionnaire answered by childrenâ?¿s parents. Correlates of fluorosis were assessed using multivariate logistic regression (p<0.05).The result showed that the prevalence of fluorosis in the municipality that had more variation in the levels of fluoride was 31.40% and in the municipality that had less variation in the levels of fluoride 79.91%. However, in both municipalities the â?¿very mildâ?? level of fluorosis was the most common finding. Fluorosis were associated to the city with homogeneous levels of fluoride
Mestrado
Mestre em Odontologia em Saúde Coletiva
8
Crispim, Cristina Penna. "Aspectos da qualidade da água potável de Ribeirão Preto - SP." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/59/59138/tde-15072013-152308/.
Full textAbstract:
A cidade de Ribeirão Preto é abastecida com água proveniente do Aquífero Guarani, sendo apenas fluoretada e clorada antes da distribuição. O objetivo desse trabalho foi avaliar a qualidade da água que a população está consumindo com relação às concentrações de fluoreto, chumbo e ferro. Além disso, foi investigada se a concentração de ferro poderia ser utilizada como marcadora da contaminação por chumbo na água potável. Foram investigadas 145 residências de 4 bairros antigos de Ribeirão Preto (casas com mais de 40 anos), havendo pelo menos uma criança moradora por residência. Um bairro novo (menos de 10 anos) foi escolhido para controle. Amostras de água foram coletadas na torneira da cozinha e do quintal, sendo a 1ª alíquota coletada após pelo menos 6 h de estagnação e a 2ª alíquota após 5 minutos de escoamento. A concentração dos íons fluoreto foi determinada por eletrodo combinado íon-seletivo e cromatografia iônica; chumbo por ET AAS e ICP-MS; e ferro por espectrofotometria. As concentrações de fluoreto nas amostras (n = 281) variaram de 0,052 a 1,01 mg L-1. Considerando apenas 1 algarismo significativo e as amostras provenientes da cozinha, observou-se que 30% das casas estiveram fora do padrão de potabilidade estabelecido pela Resolução SS-65 (2005), isto é, de 0,6 a 0,8 mg L-1. Considerado 2 algarismos, essa percentagem passou para 45%. Um baixo consumo de fluoreto pelas crianças pode não prevenir eficientemente a formação de cáries, enquanto que concentrações elevadas podem levar à fluorose dentária. As concentrações de chumbo variaram de 0,025 a 58,4 µg L-1 (n = 562), sendo que a concentração máxima permitida pela Portaria 2.914 (Ministério da Saúde) é de 10,0 µg L-1. Para todas as casas avaliadas, as concentrações de chumbo na água da torneira da cozinha não ultrapassaram 5,00 µg L-1, caracterizando um baixo risco de contaminação por chumbo por essa via. Para 2 alíquotas de água coletadas na torneira do quintal, a concentração de chumbo ultrapassou o limite tolerável para chumbo, porém, o uso dessa água para ingestão é pouco usual. Possivelmente a contaminação observada seja oriunda da própria torneira e outras partes metálicas, pois após escoamento da água por 5 minutos, a concentração de chumbo caiu dentro dos valores permitidos. As concentrações de ferro variaram de 13,40 a 4.119 µg L-1 (n = 189; 1ª alíquota), sendo a concentração máxima permitida de 300 µg L-1 (Portaria 2.914). Em 4 casas a água do quintal apresentou concentração superior a permitida, mas na água da cozinha a concentração foi de 8 a 66 vezes menor. Isso indica que a torneira do quintal pode ser uma grande fonte de contaminação de ferro. Apesar do coeficiente de correlação linear entre a concentração de ferro e chumbo na água ser estatisticamente significativo (r = 0,410; n = 184), essa correlação foi relativamente baixa para sugerir o uso do ferro como marcador da contaminação por chumbo.The city of Ribeirão Preto is supplied with water from the Guarani Aquifer, that is only fluoridated and chlorinated before distribution. The objective of this study was to evaluate the quality of drinking water that the population is consuming with respect to the concentrations of fluoride, lead and iron. Furthermore, it was investigated if the concentration of iron could be used as a marker to infer lead contamination in drinking water. We investigated 145 residences with more than 40 years of age in 4 districts of Ribeirão Preto, with at least one resident child. One new district (less than 10 years) was selected as a control group. Water samples were collected from the kitchen and the yard taps. The 1st aliquot was collected after at least 6 h of stagnation and the 2nd after leaving the water running for 5 minutes. The concentration of fluoride ions was determined by combined ion-selective electrode and ion chromatography; lead by ET AAS and ICP-MS; and iron by spectrophotometry. The fluoride concentrations in the samples varied from 0.052 to 1.01 mg L-1 (n = 281). Considering only 1 significant digit and the kitchen samples, it was observed that 30% of the homes did not attend the legislation for fluoride in drinking water (Resolution SS-65, 2005), that is, from 0.6 to 0.8 mg L-1. Considering 2 significant digits, this percentage increased to 45%. A low intake of fluoride by children cannot effectively prevent the formation of dental caries, while high concentrations can cause dental fluorosis. Lead concentrations ranged from 0.025 to 58.4 µg L-1 (n = 562), and the maximum permited by the law 2,914 (Ministry of Health) is 10.0 µg L-1. For all homes investigated, lead concentrations from the kitchens tap water did not exceed 5.00 µg L-1, showing there is a low risk of lead contamination through this pathway. For 2 aliquots of water collected from the yards tap, the concentration of lead exceeded the tolerable limit, however, the use of this water for ingestion is unusual. Possibly this contamination might come from the tap itself and from others metal parts, because after running the water for 5 minutes the lead concentration fell below the permitted value. Iron concentrations varied from 13.40 to 4,119 µg L-1 (n = 189, 1st aliquot), and the tolerable limit is 300 µg L-1 (law 2.914). In 4 houses the water from the year tap had concentrations above the limit, while in the kitchen water iron concentrations were from 8 to 66 times lower. This indicates that the tap material from the yard can be a large source of iron contamination. Although the linear correlation coefficient between iron and lead concentrations in the drinking water was statistically significant (r = 0.410; n = 184), this correlation was relatively low to suggest the use of iron as a marker of contamination by lead.
9
Forni, Tania Izabel Bighetti. "Fatores associados à fluorose dentária em área com água fluoretada." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/6/6135/tde-22092011-145657/.
Full textAbstract:
O objetivo do estudo foi identificar fatores associados à fluorose dentária em Ribeirão Pires-SP, com água fluoretada desde 1985 e heterocontrole dos teores de flúor desde 1996. Foi realizada pesquisa epidemiológica tipo caso-controle com projeto aprovado pelo Comitê de Ética da FSP-USP. A população de estudo foi adolescentes de 12 a 15 anos de idade, identificados em 23 escolas de ensino fundamental por cirurgiã-dentista capacitada (k=0,79). Foram considerados casos 667 adolescentes com graus de fluorose 2, 3, 4 e 5 (Índice de Dean). A partir da região de residência dos casos, foram identificados 416 controles, de mesmo sexo e idade, com grau de fluorose 0, procurando-se garantir a mesma distribuição por região. Casos e controles (5 por cento ) foram examinados pela pesquisadora (k=0,90). Um formulário de entrevista foi construído, utilizando-se técnica de pesquisa exploratória, contendo dados relativos a variáveis demográficas, geográficas, escolaridade dos pais/responsáveis e relacionados à exposição a fontes de flúor em três ciclos (1o ano de vida, 1 a 3 anos e 4 a 6 anos de idade). A coleta dos dados foi feita por 55 entrevistadores cujo treinamento contemplou repetição de entrevistas e discussão de aspectos relevantes. Foram realizadas 509 entrevistas (319 casos e 190 controles). As respostas foram transcritas para digitação de forma dupla, com validação do banco de dados. A distribuição percentual do evento nos casos e controles nas categorias de exposição foi analisada utilizando-se o teste de Qui-quadrado de Pearson. Na análise univariada identificou-se as de maior associação para elaboração de modelos de regressão logística múltipla não condicional. A análise mostrou risco significativo para fluorose dentária nas seguintes situações de exposição: quando os adolescentes usaram dentifrício fluoretado nos 6 primeiros anos de vida (OR= 2,25; p=0,048) e eram responsáveis pela sua colocação no período de 4 a 6 anos de idade (OR=2,17; p=0,000), quando foi utilizada água fluoretada para preparo de alimentos nos 6 primeiros anos de vida (OR=2,90; p=0,026) e a interação entre maior escolaridade do pai e menor escolaridade da mãe (OR=2,15; p=0,024). Recomenda-se que os serviços de saúde considerem os resultados no planejamento das ações de educação em saúde reforçando o uso adequado de dentifrícios, além de manter a política de vigilância sanitária dirigida a múltiplas fontes de flúorThe purpose of this study was to identify factors associated with fluorosis in the city of Ribeirão Pires SP, which has fluoridated water since 1985, (with hetero-controls of fluoride levels since 1996). It was done an epidemiological case-control study which project was approved by the Ethics Committee of the FSP-USP. The study population consisted of 12 to 15 year old teenagers, identified by a trained dentist (k=0.79) in 23 high schools. 667 teenagers who showed fluorosis levels of 2, 3, 4 or 5 (Dean Index) were selected for this study. 416 children of the same age and sex and living in the same area were also identified as controls (fluorosis level = 0) in order to assure the same distribution by region. Cases and controls (5 per cent ) were examined (k=0.90) by the author. A questionnaire was elaborated, using the exploratory survey method, with data related to demographic, geographic, education level of parents/guardians, related to fluoride sources exposure in 3 different periods of life (first year, 1 to 3 years and 4 to 6 years of age). Data was collected by 55 interviewers whose training consisted of repeated interviews and case discussions. 509 interviews were made (319 cases and 190 controls) and the responses were transcribed and typed twice, with posterior validation of the database. Percentile distribution of the events of cases and controls of exposition categories were analyzed using Pearson Chi-Square test. In the univariable analysis, the variables with higher match were identified for posterior construction of models of non-conditional multiple logistic regression analyses. The analysis of regression showed significant risk for dental fluorosis in the following exposure situations: when the teenagers used fluoridated dentifrice during the first 6 years of life (OR=2.25; p=0.048) and they were responsible for its placement in a period of 4 to 6 years (OR=2.17; p=0.000), when it was used fluoridated water for food preparation during the 6 first years of life (OR=2.90; p=0.026) and in the relation of high educational level of the father and lower educational level of the mother (OR=2.15; p=0.024). It is recommended that the health services should consider these results in the planning of actions of health education activities in order to emphasize the importance of adequate use of dentifrices, and to maintain their sanitary control policies focused on multiple sources of fluoride
10
Barbosa, Tatiana de Freitas [UNESP]. "Fluorose dentária e concentração de flúor nas unhas de crianças residentes em diferentes áreas fluoretadas." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/95402.
Full textAbstract:
Made available in DSpace on 2014-06-11T19:27:45Z (GMT). No. of bitstreams: 0
Previous issue date: 2010-08-12Bitstream added on 2014-06-13T20:56:49Z : No. of bitstreams: 1
barbosa_tf_me_araca.pdf: 715889 bytes, checksum: f9c4cf0b3fff1513c875f5ce77fdf964 (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
A fluoretação das águas de abastecimento público tem ocasionado significante redução na prevalência da cárie em diferentes populações, entretanto, a exposição ao flúor pelo uso de diferentes métodos tem trazido preocupações quanto ao aumento na prevalência de fluorose dentária. Por isso, estudos sobre os fatores de risco associados à fluorose são necessários, além do acompanhamento contínuo e efetivo da exposição ao flúor, por diferentes meios, incluindo mais recentemente os marcadores biológicos para esse íon, como a unha, que também reflete o nível de exposição crônica, desde que um indivíduo tenha uma ingestão de flúor relativamente constante. Assim, objetivou-se analisar o teor de fluoreto das águas de abastecimento público em diferentes áreas de um município, uma abastecida por poços profundos e outra pela estação de tratamento de água (ETA), e verificar se os teores de fluoretos encontrados refletem diferenças nas concentrações de flúor observadas nas unhas das crianças de 12 anos e na prevalência de fluorose dentária. Para isso, foram selecionados 43 pontos para coleta de amostras de água, abrangendo as 17 fontes de abastecimento existente no município. A população de estudo foi constituída por 60 crianças, de 12 anos de idade, nascidas e moradoras permanentes nas duas áreas de estudo, seguindo os critérios de inclusão, sendo uma com excesso e outra sem excesso de flúor nas águas de abastecimento público. As amostras de água, coletadas mensalmente nos pontos previamente estabelecidos, foram analisadas em duplicata no período de janeiro a dezembro de 2009, utilizando-se um analisador de íons acoplado a um eletrodo específico para flúor. Coletas e análise do flúor nas unhas das crianças foram realizadas, utilizando-se a técnica da microdifusão facilitada por HMDS. Para verificação da fluorose...
The fluoridation of public water supply has caused a significant reduction in the prevalence of caries in different populations, however, exposure to fluoride by using different methods has brought concerns about the increasing prevalence of dental fluorosis. Therefore, studies on the risk factors associated with fluorosis are needed, besides the efficient and continuous monitoring of fluoride exposure by various means, including most recently the biological markers for this ion, such as fingernail, that also reflects the level of chronic exposure, as long as an individual has a relatively constant intake of fluoride. The objective was to analyze the fluoride content of public water supply in different areas of a district, one served by deep wells and one by the water treatment station (WTS), and check if the levels of fluoride found reflect differences in the concentrations of fluoride observed in nails of 12 years old children and the prevalence of dental fluorosis. For this, 43 points were selected to collect water samples, covering the 17 existing sources of supply in the municipality. The study population consisted of 60 children, 12 years old, born and permanent residents in both areas of study, following the inclusion criteria, one with and one without too much fluoride excess in public water supply. Water samples collected monthly in points previously established, were analyzed in duplicate in the period from January to December of 2009, using an ion analyzer coupled to a specific electrode for fluoride. Sampling and analysis of fluoride in children nails were done, using the technique of facilitated microdiffusion HMDS. For verification of dental fluorosis we used the modified DEAN index .Of the total samples studied (n=512), 44% (n=224) had adequate levels and 56% (n =288) inadequate levels, and 10% (n=49) lower levels and 46% (n=239) higher... (Complete abstract click electronic access below)
Books on the topic "Fluorace"
1
Preedy, Victor R., ed. Fluorine. Cambridge: Royal Society of Chemistry, 2015. http://dx.doi.org/10.1039/9781782628507.
Full text
3
International Society for Fluoride Research. Conference. Fluoride toxicity. Edited by Susheela A. K and International Society for Fluoride Research. [New Delhi: Distributed by Dept. of Anatomy, All India Inst. of Medical Sciences, 1985.
Find full text
4
Jäger, Susanne, Jörn von Jouanne, Hannelore Keller-Rudek, Dieter Koschel, Peter Kuhn, Peter Merlet, Sigrid Rupecht, Hans Vanecek, and Joachim Wagner. F Fluorine. Edited by Dieter Koschel, Peter Kuhn, Peter Merlet, Sigrid Ruprecht, and Joachim Wagner. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-662-06339-2.
Full text
7
Crull, Anna W. Commercial fluorine compounds. Norwalk, CT: Business Communications Co., 1989.
Find full text
8
Braun, Thomas, and Russell P. Hughes, eds. Organometallic Fluorine Chemistry. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-22096-3.
Full text
9
Soloshonok, Vadim A., ed. Fluorine-Containing Synthons. Washington, DC: American Chemical Society, 2005. http://dx.doi.org/10.1021/bk-2005-0911.
Full text
10
Thrasher, Joseph S., and Steven H. Strauss, eds. Inorganic Fluorine Chemistry. Washington, DC: American Chemical Society, 1994. http://dx.doi.org/10.1021/bk-1994-0555.
Full textBook chapters on the topic "Fluorace"
1
Nakajima, Tsuyoshi. "Preparation of Carbon-Fluorine Compounds and Fluoride or Oxide Fluoride-Intercalated Graphites." In Efficient Preparations of Fluorine Compounds, 425–32. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118409466.ch65.
Full text
2
Dénès, G., M. C. Madamba, A. Muntasar, A. Peroutka, K. Tam, and Z. Zhu. "Fluoride-Ion Conductors Derived from the Fluorite Type." In Mössbauer Spectroscopy in Materials Science, 25–38. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4548-0_3.
Full text
3
Nyairo, Wilfrida Nyanduko, Emily Ng'eno, Victor Odhiambo Shikuku, and Patrick Ssebugere. "Application of Metal-Organic Framework Adsorbents for Water Defluoridation." In Emerging Applications and Implementations of Metal-Organic Frameworks, 74–91. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4760-1.ch005.
Full textAbstract:
Defluoridation of drinking water is a subject of great concern due to the side effects of exposure to fluorine such as fluorosis, damage to vital organs such as the brain, liver, and kidney, among others. Fluorine finds itself in water resources both by geological and anthropogenic processes. Adsorption still remains the popular method of defluoridation and water treatment in general due to its inherent advantages such as simplicity and low-cost. This chapter discusses at length the up-to-date data on the preparation and adsorption capacities of metal-organic framework (MOF) materials as emerging adsorbents for sequestration of fluoride from water. Their synthesis, efficiency, and suggested adsorption mechanisms are examined. It is demonstrated that MOFs are low-cost, efficient, and environmentally benign alternative adsorbents for the removal of fluoride from aqueous solution.
4
"8. Fluorine, Fluorite, and Fluorine-Based Materials." In Industrial Inorganic Chemistry, 53–60. De Gruyter, 2015. http://dx.doi.org/10.1515/9783110330335-009.
Full text
5
Orakpoghenor, Ochuko, Talatu Patience Markus, Meshack Inotu Osagie, and Paul Terkende Hambesha. "Fluoride Content in Drinking Water and the Health Implications of Fluoride-Rich Water Consumption: An Overview of the Situation in Canada and Nigeria." In Environmental Health [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.97209.
Full textAbstract:
Fluoride is an inorganic monatomic anion of fluorine and forms part of essential reagents used by the chemical industry. It occurs naturally in several minerals and in trace quantities in water. Fluoride has been used to prevent tooth decay and in the treatment of osteoporosis. Extensive research has consistently demonstrated the safety and effectiveness of fluorides in the prevention of dental caries following the practice of water fluoridation. Despite these benefits, fluorides pose danger as an endocrine disruptor thus, affecting bones, brain, thyroid gland, pineal gland and blood sugar levels. In Canada, water fluoridation remains a contentious issue although dental decay constitutes the most common chronic disease. However, several Canadians are receiving the benefits of water fluoridation and about 1% have access to naturally fluoridated water. In Nigeria, the prevalence of dental caries has been documented to be greatly reduced following fluoridation of public water supplies in areas where the condition was endemic. Fluoride is therefore the only medicine added to public water, and at the recommended level, fluoride is safe and effective in the reduction of dental decay and poses no risk for health problems. Hence, this article highlighted fluoride content in drinking water and the health implications of consuming fluoride-rich water with a focus on the situation in Canada and Nigeria.
6
"Thermodynamic Aspects of the Intercalation of Graphite." In Fluorine-Carbon and Fluoride-Carbon Materials, 77. CRC Press, 1994. http://dx.doi.org/10.1201/9781482293562-10.
Full text
7
"pi: orbitals of the carbon atoms, generates bonding normal to the sheets,." In Fluorine-Carbon and Fluoride-Carbon Materials, 78–83. CRC Press, 1994. http://dx.doi.org/10.1201/9781482293562-11.
Full text
8
"k = coefficient of compressibility along the c-axis, 5 X 10 11 m2 N 1 d0 = interplanar distance of graphite layer of the original graphite,." In Fluorine-Carbon and Fluoride-Carbon Materials, 84–104. CRC Press, 1994. http://dx.doi.org/10.1201/9781482293562-12.
Full text
9
"Physical Properties of Fluorine- and Fluoride-Graphite Intercalation Compounds." In Fluorine-Carbon and Fluoride-Carbon Materials, 105–7. CRC Press, 1994. http://dx.doi.org/10.1201/9781482293562-13.
Full text
10
"aa is very much more pro." In Fluorine-Carbon and Fluoride-Carbon Materials, 108–9. CRC Press, 1994. http://dx.doi.org/10.1201/9781482293562-14.
Full textConference papers on the topic "Fluorace"
1
Younan, Hua, Nistala Ramesh Rao, and Teong Jennifer. "Studies of Fluorine-Induced Corrosion and Defects on Microchip Al Bondpads and Elimination Solutions." In ISTFA 2008. ASM International, 2008. http://dx.doi.org/10.31399/asm.cp.istfa2008p0285.
Full textAbstract:
Abstract In this paper, a comprehensive study of Fluorine-induced Aluminum bondpad corrosion will be presented. Fluorine corrosion is detrimental to Al pad quality resulting in non-stick on pad (NSOP). In wafer fabrication, NSOP refers to lift-off of Au wire-bond from the surface of Al bondpad due to its poor adhesion to the contaminated pad surface. It will be shown that besides the well-known corrosion mechanism that causes NSOP, namely, via the formation of Al fluoride defect ([AlFx](x-3)-), it can also happen due to Al fluoride oxide defect, AlxOyFz. Unlike the Al fluoride defect, which has a unique “flower-like” shape, Al fluoride oxide defects exist in a variety of shapes: “Crystal-like”, “Oxide-like” and “Cloud-like”. The physical dimensions of these defects (including Al fluoride) can be dramatically different, varying all the way from micron to nanometer. In this paper, each of these morphological shapes and their respective failure mechanisms will be covered. Solutions to mitigate F-corrosion and ways to control/monitor contamination on Al pad surface in wafer fab will be presented.
2
Luo, Zhi-Yong, Dong-Chuan Mo, and Shu-Shen Lyu. "Fluorine-Induced Superhydrophilic TiO2 Nanotube Arrays." In ASME 2016 5th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/mnhmt2016-6328.
Full textAbstract:
Continuous water film formed on a hydrophilic or superhydrophilic surface can delay the formation of a vapor film in boiling and thus improve critical heat flux (CHF), therefore, the fabrication of hydrophilic or superhydrophilic surface is an efficient approach to enhance boiling heat transfer. In the present work, superhydrophilic TiO2 nanotube arrays (TiNAs) interfaces are fabricated by anodization in fluoride contained electrolyte, and the fluorine is found out to be the key factor affecting the wettability of TiNAs interfaces. After anodization, a stable oxy-fluoride layer was formed at the interface as form of -O-Ti-F, the fluorine atoms are linked to the interface as terminal groups. Due to the strong polarity of titanium oxy-fluorides, superhrophilic TiO2 nanotube arrays interface is obtained. Furthermore, we characterize the stability of titanium oxy-fluorides by storing. After store for 2 months, the inner titanium fluorides (TiF4) are lost due to its strong volatility. Fortunately, the content of titanium oxy-fluorides remains the same, and retain its remarkable superhydrophilic properties. It is potential to design energy-efficient devices ranging from boiling heat transfer to self-cleaning.
3
Yedave, Sharad, Ying Tang, Joseph Sweeney, and Joseph Despres. "Fluorine Beam Performance of Fluoride Dopant Gases and Their Gas Mixtures." In 2018 22nd International Conference on Ion Implantation Technology (IIT). IEEE, 2018. http://dx.doi.org/10.1109/iit.2018.8807945.
Full text
4
Barnhart, T. E. "Revisiting Low Energy Deuteron Production of [18F] Fluoride and Fluorine for PET." In APPLICATION OF ACCELERATORS IN RESEARCH AND INDUSTRY: 17TH International Conference on the Application of Accelerators in Research and Industry. AIP, 2003. http://dx.doi.org/10.1063/1.1619896.
Full text
5
K.H.I, Gamage, Wickramasinghe R.S.R, and Gamage I.M.C. "Groundwater Quality Assessment in Anuradhapura for Domestic Purposes." In 2nd International Conference on Agriculture, Food Security and Safety. iConferences (Pvt) Ltd, 2021. http://dx.doi.org/10.32789/agrofood.2021.1006.
Full textAbstract:
The North central province plays the main agricultural role in Sri Lanka as a developing agricultural-based economy country in the world. Excessive amount of nitrate and fluoride in groundwater consumption is becoming a crucial issue on human health in Sri Lanka, especially in the North Central part of the country. Dental fluorosis and skeleton fluorosis are the major health impacts based on an excessive amount of fluoride as well as presumption on causing chronic kidney disease (CKD). Nitrogenous compounds in groundwater for drinking have been considered possible risk factors for oesophageal cancer and haemoglobinemia or blue baby syndrome. Human activities and natural processes have polluted groundwater. Having a lack of understanding of the actual need for fertilizer, farmers usually tend to apply the surplus amount, thus increasing nitrogen pollution. Accordingly, this research was conducted to deepen the understanding of the distribution of fluoride and nitrate in groundwater in the Anuradhapura area in terms of geological and anthropogenic influences on groundwater quality. Well water samples were collected from intensive agricultural activity areas in Anuradhapura. Physical and chemical parameters were analyzed to identify whether the higher nitrate and fluoride or any compound of a mixture of heavy metals such as cadmium and/ or arsenic is the actual cause for kidney and other health-related issues among the community. Water samples' pHs were in the range of 6.7-7.7. All the wells can be categorized as low salinity water. Turbidity average of 3.51 NTU range of 1-8 NTU was found to be mainly contributed by nitrate at the average of 28.725 mg/L and ranged from (22-131) mg/L of nitrate. In addition, fluorite was found high in Anuradhapura with an average of 0.6 mg/L and ranged from (0.4 - 1.7) mg/L. Sulphate level was also high with an average of 178mg/L and ranged from (58-505 mg/L). There was no significant effect of heavy metals such as cadmium, arsenic, iron, and copper concentrations which were below the permissible level of 0.01mg/L. The research clearly indicates the abundance of nitrate and fluoride in groundwater, especially in the dry zone. The major sources are fluoride-bearing minerals in bedrock and soil zone. In addition to that, the influence of agriculture which causes excessive nitrate levels in groundwater, is apparent, irrespective of climatic zones.
6
PASHKEVICH, DMITRII S., and ANTON V. MAMAEV. "PRODUCTION OF HYDROGEN FLUORIDE BY PROCESSING FLUORINE-CONTAINING WASTES AND BY-PRODUCTS OF MODERN INDUSTRIES." In WASTE MANAGEMENT 2018. Southampton UK: WIT Press, 2018. http://dx.doi.org/10.2495/wm180111.
Full text
7
Liu, Stephen, Craig Clasper, Keith Moline, and Joe Scott. "Ultra-Low Hydrogen Consumables for Welding of High Strength Steels With 690–750 MPa-Yield Strength." In 25th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/omae2006-92633.
Full textAbstract:
Two fundamental concepts in welding consumable development were explored in this research. The first concept dealt with the introduction of yttrium-containing oxides into the weld metal for microstructural control and hydrogen trapping. The second concept suggested the use of fluoride species to displace hydrogen from the arc. Combining yttrium and fluorides into one single flux-cored consumable to capture the benefit of hydrogen reduction from both ingredients, however, proved to be difficult. The oxygen potential controlled by yttrium clashed with the fluorine potential controlled by KF. Several iterations led to the successful reconciliation of the oxygen potential and fluorine potential and the development of a new generation of flux-cored consumables with exceptional performance. Using CO2 as shielding gas, these consumables successfully produced welds that contained only 0.6 ml H2/100 g weld metal. With a duplex martensite-acicular ferrite microstructure, a weld metal with yield strength of 99 ksi and tensile strength of 108 ksi was obtained. The weld metal exhibited excellent ductility, 21.8% elongation. Impact toughness exceeded the −60 °F requirement by 88%, reaching values of 76 ft-lb. Charpy-V-notch energy at 0 °F testing temperature measured an outstanding average of 89 ft-lbs. Consumables designed using the two fundamental concepts have demonstrated great capability of producing high strength steel welds that met stringent mechanical performance requirements.
8
Wu Qian, Liu Jian, and Wu Ruilin. "Study on preparation of defluoridation gel and its performance of fluorine removal from water including fluoride." In 2011 International Symposium on Water Resource and Environmental Protection (ISWREP). IEEE, 2011. http://dx.doi.org/10.1109/iswrep.2011.5893264.
Full text
9
VanBrocklin, H. F., and J. P. O’Neil. "Cyclotron production of [[sup 18]F]fluoride ion and [[sup 18]F]fluorine gas and their medical applications." In The fourteenth international conference on the application of accelerators in research and industry. AIP, 1997. http://dx.doi.org/10.1063/1.52645.
Full text
10
Fiore, Susan. "New FCAW Electrode for Producing Ultra-Clean High-Toughness Welds in X-80 and X-100 Steel." In 2016 11th International Pipeline Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/ipc2016-64361.
Full textAbstract:
The challenges associated with the welding of high-strength pipeline steels, such as X-80 and X100, are well established. While there are many filler metals that provide either adequate strength or good impact toughness, it is difficult to find products that provide both. Add to that the need for all-position welding and high deposition rates, and the options become almost non-existent. Several years ago, Hobart® Filler Metals began working on a line of flux-cored arc welding (FCAW) consumables that are unique in the welding industry. The products have a basic slag system, but do not operate like traditional EXXXT-5 electrodes. Traditional T-5 electrodes have a low-melting, fluid slag, which makes welding out-of-position especially difficult. They also have a high level of calcium fluoride, which affects the stability of the arc and causes weld spatter. While the weld metal mechanical properties and crack-resistance are excellent, the welder appeal and ease-of-use tend to be sorely lacking in most EXXXT-5 electrodes. The new approach utilizes aluminum for deoxidation, which has the added benefit of very clean weld deposits. The composition has been carefully optimized with appropriate levels of carbon, silicon, nickel and manganese. Alternative fluorine sources are used in place of calcium fluoride, which results in very good welder appeal and all-positional capabilities, including vertical down. The novel use of aluminum in a gas shielded process results in very low oxygen, nitrogen and sulfur content, providing exceptionally clean, tough weld deposits. Although the new products have been produced over a range of strength levels, the primary emphasis of this paper is on E691T5-GC (E101T5-GC) and E831T5-GC (E121T5-GC) electrodes. Testing shows that tensile strength levels ranging from 700–880 MPa (100–128 ksi) can be achieved, with toughness levels of 120 J at −60°C (90 ft-lbs at −76°F) or better. The highly basic slag, combined with low weld metal hydrogen (less than 4 ml/100 gm), provides excellent resistance to cracking. The product can be used in all positions, including vertically down, making it an especially appealing choice for welding high-strength pipe.
Reports on the topic "Fluorace"
1
Rose, M., E. Wu, T. Lichtenstein, J. Krueger, S. Thomas, and M. Williamson. Quantify Sodium Fluoride / Beryllium Fluoride Salt Properties for a Liquid Fueled Fluoride Molten Salt Reactor. Office of Scientific and Technical Information (OSTI), January 2021. http://dx.doi.org/10.2172/1764854.
Full text
2
Vij, Ashwani, William Wilson, Vandana Vij, Karl Christe, and F. Tham. Nitrogen Fluoride Chemistry. Fort Belvoir, VA: Defense Technical Information Center, June 2002. http://dx.doi.org/10.21236/ada408824.
Full text
3
Jaeger, Raymond E., and Lubos J. Vacha. SBIR-Long Fluoride Fiber. Fort Belvoir, VA: Defense Technical Information Center, August 1987. http://dx.doi.org/10.21236/ada188595.
Full text
4
Collings, R. K., and P. R. A. Andrews. Summary report no. 3: fluorite. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1988. http://dx.doi.org/10.4095/307286.
Full text
5
Burakovsky, Leonid, Samuel Baty, Darby Luscher, and Sky Sjue. Thermoelasticity Model for Lithium Fluoride. Office of Scientific and Technical Information (OSTI), June 2020. http://dx.doi.org/10.2172/1632675.
Full text
6
Gupta, P. K. Stable Compositions for Fluoride Glasses. Fort Belvoir, VA: Defense Technical Information Center, April 1988. http://dx.doi.org/10.21236/ada196021.
Full text
7
Christe, Karl O. Research in Inorganic Fluorine Chemistry. Fort Belvoir, VA: Defense Technical Information Center, March 1987. http://dx.doi.org/10.21236/ada179863.
Full text
8
Christe, K. O., W. W. Wilson, C. J. Schack, E. C. Curtis, and R. D. Wilson. Research in Inorganic Fluorine Chemistry. Fort Belvoir, VA: Defense Technical Information Center, May 1991. http://dx.doi.org/10.21236/ada238348.
Full text
9
Aaron, Adam M., Richard Burns Cunningham, David L. Fugate, David Eugene Holcomb, Roger A. Kisner, Fred J. Peretz, Kevin R. Robb, Dane F. Wilson, and Graydon L. Yoder, Jr. High Temperature Fluoride Salt Test Loop. Office of Scientific and Technical Information (OSTI), December 2015. http://dx.doi.org/10.2172/1237612.
Full text
10
Hoge, B., and K. O. Christe. A New Synthesis of Fluorine Nitrate. Fort Belvoir, VA: Defense Technical Information Center, October 2000. http://dx.doi.org/10.21236/ada408583.
Full text