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Tytuł:
Fluoride content in the Antarctic krill (Euphausia superba Dana) in relation to its biological condition and to the fishery region
Autorzy:
Bykowski, Piotr
Kowalczuk, Maria
Powiązania:
https://bibliotekanauki.pl/articles/2053305.pdf
Data publikacji:
1986
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Antarctic
krill
fluoride content
Źródło:
Polish Polar Research; 1986, 7, 3; 283-287
0138-0338
2081-8262
Pojawia się w:
Polish Polar Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fluoride concentration in teeth of the roe deer (Capreolus capreolus) and red deer (Cervus elaphus) from areas of Poland industrially uncontaminated with fluoride compounds
Autorzy:
Palczewska-Komsa, M.
Barczak, K.
Grocholewicz, K.
Buczkowska-Radlińska, J.
Piotrowski, P.R.
Sobolewska, E.
Powiązania:
https://bibliotekanauki.pl/articles/2087218.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fluoride
biomonitoring
teeth
herbivorous
mammals
Źródło:
Polish Journal of Veterinary Sciences; 2021, 24, 1; 151-157
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nanofiltration usage for fluoride removal in the sodium chloride presence
Autorzy:
Grzegorzek, Martyna
Powiązania:
https://bibliotekanauki.pl/articles/2073802.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fluoride
nanofiltration
sodium chloride
membrane processes
Opis:
Fluorine and sodium chloride are common elements present in the water environment. According to WHO guidelines fluoride content in water cannot be not higher than 1.5 mF-/dm3. Elevated fluoride content was observed all over the world and it leads to many health issues. It can be removed with the usage of various methods (ion exchange, membrane processes, adsorption, precipitation). In this paper fluoride removal with nanofiltration usage was described. Tests were performed with the application of Amicon 86400 filtration cells. Two types of commercial nanofiltration membranes NP010P and NP030P (Microdyn Nadir) were used. Transmembrane pressure was established as 0.3 MPa. For lower fluoride concentrations (5 mgF-/dm3) NF process allowed to decrease fluoride content under level 1.5 mgF-/dm3. Removal efficiency decreased with increasing fluoride content. Membrane NP030P showed better separation properties. Sodium chloride influenced removal efficiency as well as fluoride adsorption on/in membranes during the process. According to obtained data, better hydraulic properties exhibited membrane NP010P. For both membranes decrease in permeate flux in comparison to pure water was noticed what was observed. Relative permeability was lowered even to 0.32.
Źródło:
Archives of Environmental Protection; 2021, 47, 4; 98--108
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of process-material conditions on the structure and biological properties of electrospun polyvinylidene fluoride fibers
Autorzy:
Zaszczyńska, A.
Sajkiewicz, P. Ł.
Gradys, A.
Tymkiewicz, R.
Urbanek, O.
Kołbuk, D.
Powiązania:
https://bibliotekanauki.pl/articles/200237.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
scaffolds
electrospinning
polyvinylidene fluoride
tissue engineering
Opis:
Polyvinylidene fluoride (PVDF) is one of the most important piezoelectric polymers. Piezoelectricity in PVDF appears in polar b and ɣ phases. Piezoelectric fibers obtained by means of electrospinning may be used in tissue engineering (TE) as a smart analogue of the natural extracellular matrix (ECM). We present results showing the effect of rotational speed of the collecting drum on morphology, phase content and in vitro biological properties of PVDF nonwovens. Morphology and phase composition were analyzed using scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR), respectively. It was shown that increasing rotational speed of the collector leads to an increase in fiber orientation, reduction in fiber diameter and considerable increase of polar phase content, both b and g. In vitro cell culture experiments, carried out with the use of ultrasounds in order to generate electrical potential via piezoelectricity, indicate a positive effect of polar phases on fibroblasts. Our preliminary results demonstrate that piezoelectric PVDF scaffolds are promising materials for tissue engineering applications, particularly for neural tissue regeneration, where the electric potential is crucial.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 3; 627-633
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A near-infrared fluorescent probe for selective detection of fluorion
Autorzy:
Kang, Yan-Fei
Wei, Fan
Meng, Ya-Li
Xin, Zhen-Hui
Wei, Dong
Powiązania:
https://bibliotekanauki.pl/articles/778367.pdf
Data publikacji:
2020
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Probe
Fluorescence
Fluoride anion
Selectivity
Near-infrared
Opis:
In this work, we have designed and synthesized the fluorescent probe 1, which was capable to selectively detect fluoride anion (F−). More importantly, the probe 1 possessed near-infrared excitation and emission wavelengths (excitation at 650 nm and emission at 695), and the probe solution had changed dramatically from yellow to cyan with the addition of F–. In addition, the fluorescence intensity exhibited perfectly positive correlation with concentration of F− concentration from 0 to 40 μM (R2 = 0.9972), which offered the important condition for quantitative analysis. The probe 1 owned detection limit of 46 nM. Therefore, this near-infrared probe can be of great benefit for detecting F− in practical application.
Źródło:
Polish Journal of Chemical Technology; 2020, 22, 1; 1-5
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of sodium fluoride on seeds germination and morphophysiological changes in the seedlings of the Antarctic species Colobanthus quitensis (Kunth) Bartl.and the Subantarctic species Colobanthus apetalus (Labill.) Druce
Autorzy:
Dulska, Justyna
Wasilewski, Janusz
Androsiuk, Piotr
Kellmann-Sopyła, Wioleta
Głowacka, Katarzyna
Górecki, Ryszard
Chwedorzewska, Katarzyna
Giełwanowska, Irena
Powiązania:
https://bibliotekanauki.pl/articles/2041858.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Antarctic
Colobanthus apetalus
Colobanthus quitensis
fluoride stress
Źródło:
Polish Polar Research; 2019, 40, 3; 255-272
0138-0338
2081-8262
Pojawia się w:
Polish Polar Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes of Fluoride Content in Sand From Sandboxes Located on Playgrounds in Police (West Pomerania, Poland)
Autorzy:
Telesiński, A.
Człaczyńska-Podolska, M.
Węgrzynowski, Z.
Biczak, R.
Telesińska, N.
Powiązania:
https://bibliotekanauki.pl/articles/123733.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
distance from emitter
fluoride
risk assessment
sandboxes
Opis:
The aim of the study was to determine fluoride content in sand from sandboxes in Police town (West Pomerania, Poland). This area is exposed to excessive emissions of fluoride compounds because of the proximity of chemical plants. The sand samples were collected five times in a period from March to November in 2016. Fluoride content was determined using the potentiometric method with an ion-selective fluoride electrode. The obtained results showed that fluoride content was ranged from 0.09 to 1.48 mg·kg-1 dm. The lowest fluoride content was recorded in the sand collected in place, which was the closest to the emitter, and the largest in the samples from sandbox, which was furthest from the emitter. Analyzing the changes in the content of this element over time, the largest fluoride concentration of sand occurred in July or September depending on location. Pearson correlation coefficient at p < 0.05 (r = 0.925) showed a significant positive correlation between fluoride content and the distance from fluoride emitter.
Źródło:
Journal of Ecological Engineering; 2017, 18, 5; 168-172
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Fluoride and Bentonite on Biochemical Aspects of Oxidative Stress in Pisum sativum
Autorzy:
Śnioszek, M.
Telesiński, A.
Smolik, B.
Zakrzewska, H.
Powiązania:
https://bibliotekanauki.pl/articles/125180.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
fluoride
bentonite
oxidative stress
antioxidants
Pisum sativum
Opis:
Fluoride is regarded as one of the strongest oxidants, which causes oxidative changes in cells of living organisms. It may both increase the content of reactive oxygen species and inhibit the activity of antioxidative enzyme. In recent years, many researchers successfully used the properties of clay minerals in the sorption of fluoride ion from water. This raises the question of the possibility of limiting the effect of fluorine on the negative changes in plants by adding bentonite to soil. A two-year pot experiment was carried out in the Greenhouse of West Pomeranian University of Technology in Szczecin, on loamy sand and sandy loam. Each sample of soil was mixed with three different concentrations of bentonite – 1, 5, 10% of dry weight (DW) of the soil and then treated with 30 mmol of F- per 1 kg of dry weight of the soil in a form of NaF solution. A control series was prepared for each soil, to which no additives were added. The medium prepared in such way was transferred to plastic pots (3 kg each) and seeded with 16 pea seeds of Pisum sativum. In three phases of pea development (4 leaves unfolded, flowering and development of fruit), fresh leaf samples were collected and the concentrations of ascorbic acid, reduced glutathione, total flavonoids and total polyphenols were measured. Sodium fluoride introduced to the soil changed the level of antioxidant parameters in the plant, which may suggest that fluoride is involved in the formation of reactive oxygen species, resulting in oxidative stress. Bentonite in a dosage of 10% reduced the toxic effects of fluoride on the oxidative balance and morphological changes in the plant, which was observed especially for loamy sand, naturally poor in clay minerals.
Źródło:
Journal of Ecological Engineering; 2018, 19, 2; 164-171
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Removal of fluoride ions by batch electrodialysis
Autorzy:
Majewska-Nowak, K.
Grzegorzek, M.
Kabsch-Korbutowicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/207831.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fluorine compounds
biological materials
electrodialysis
fluoride concentrations
fluoride removal
związki fluoru
materiały biologiczne
elektrodializa
stężenie fluorków
usuwanie fluorków
Opis:
Suitability of conventional batch electrodialysis to fluoride removal from aqueous solutions has been investigated. The experiments were conducted with the use of laboratory installation PCCell BED-1 System at a constant current density (1.56 or 2.34 mA/cm2). The influence of initial fluoride and salt (NaCl) concentration, as well as the presence of organic matter on the process performance was studied. It was found that the separation efficiency increased upon decrease of initial fluoride content in model solutions. Permissible final concentration of fluorides in the product water (1.5 mg/dm3) was obtained for experiments with solutions of initial fluoride concentration equal to 5 mg F–/dm3 and 10 mg F–/dm3. The presence of humic acids in fluoride solutions subjected to electrodialysis treatment has no adverse effect on the defluorization and desalination efficiency. The calculated electrical energy demand depended on composition of fluoride solution and varied from 0.121 to 0.895 kWh/m3.
Źródło:
Environment Protection Engineering; 2015, 41, 1; 67-81
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Minimizing fluoride by coagulation on iron(III) hydroxide in drinkable water from Oasis region of Algeria
Autorzy:
Atia, D.
Hoggui, A.
Powiązania:
https://bibliotekanauki.pl/articles/411515.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Oasis region
minimizing fluoride
fluorosis
coagulation
drinkable water
Opis:
The drinkable water in oasis region of Algeria contains high quantity of fluoride which causes dental fluorosis. To reduce fluoride, we have chosen a sample with the biggest content of fluoride among many sources in order to coagulate it with FeSO4·H2O. After that the parameters influencing (concentration, pH, temperature) are studied to choose the best conditions for better reduction.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 7, 1; 23-29
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charakterystyka wybranych właściwości materiałów kompozytowych na stałe wypełnienia stomatologiczne
The characteristic of selected properties of composite materials for dental fillings
Autorzy:
Mystkowska, J.
Powiązania:
https://bibliotekanauki.pl/articles/285286.pdf
Data publikacji:
2007
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
kompozyty
uwalnianie fluoru
nanokrzemionka
composites
fluoride release
nanosilica
Opis:
W pracy przedstawiono wyniki badań wpływu napełniaczy proszkowych na procesy uwalniania fluoru z kompozytowych materiałów na stałe wypełnienia stomatologiczne. Oceniano wpływ fluorku strontu oraz nanokrzemionki na ilość uwalnianego fluoru. Emisję jonów fluorkowych analizowano przy pomocy metody potencjometrii bezpośredniej z zastosowaniem fluorkowej elektrody jonoselektywnej. Badano także chropowatość powierzchni oraz mikrotwardość analizowanych kompozytów.
This work presents results of research of the influence two filler powders on fluorine release from composite materials for dental fillings. The influence of fluoride strontium and nanosilica on fluorine release was investigated. Fluorine release was measured using direct potentiometry method with fluoride electrode. The surface roughness and microhardness were also analyzed.
Źródło:
Engineering of Biomaterials; 2007, 10, no. 69-72; 22-25
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Fluoride Ions in Artificial Saliva Solution to Corrosion Behavior of Ti-6Al-4V and Ti-10Mo-4Zr Titanium Alloys
Autorzy:
Loch, J.
Krawiec, H.
Powiązania:
https://bibliotekanauki.pl/articles/106985.pdf
Data publikacji:
2018
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
titanium alloys
artificial saliva solution
fluoride ions
corrosion
Opis:
Titanium alloys used in medical applications (especially dentistry) are exposed to the actions of various compounds that appear periodically in the mouth. Fluorine compounds are dangerous for the surface of titanium alloys, because they generate a dissolution of the passive layer. In this way, they destroy the surface of dental implants and cause the absorption of metal ions into the human body. The presented work was aimed to describe the effect of fluoride ions on the corrosive behavior of the commercial Ti-6Al-4V and new Ti-10Mo-4Zr alloys that can be used in stomatology. Electrochemical measurements such as open circuit potential (OCP), linear sweet voltamperometry (LSV) and impedance spectroscopy (EIS) were performed to get information on the corrosive behavior of titanium in artificial saliva solutions (MAS) with different concentrations of NaF. It has been revealed that a high concentration of fluoride ions enhance the current density in the anodic domain, especially for the Ti-10Mo-4Zr alloy. EIS measurements performed at a potential of 0.5 V vs. AgCl (3 M KCl) show that the Ti-10Mo-4Zr alloy has a typical two-layer structure of its passive film. This passive film consists of the outer and inner layers, respectively. The resistance of the outer layer is significantly lower than the resistance of the inner layer.
Źródło:
Journal of Casting & Materials Engineering; 2018, 2, 3; 57-62
2543-9901
Pojawia się w:
Journal of Casting & Materials Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pyrochemical reprocessing of molten salt fast reactor fuel : focus on the reductive extraction step
Autorzy:
Rodrigues, D.
Durán-Klie, .
Delpech, S.
Powiązania:
https://bibliotekanauki.pl/articles/147983.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
molten salt reactor
reductive extraction
fluoride molten salt
pyrochemistry
Opis:
The nuclear fuel reprocessing is a prerequisite for nuclear energy to be a clean and sustainable energy. In the case of the molten salt reactor containing a liquid fuel, pyrometallurgical way is an obvious way. The method for treatment of the liquid fuel is divided into two parts. In-situ injection of helium gas into the fuel leads to extract the gaseous fission products and a part of the noble metals. The second part of the reprocessing is performed by ‘batch’. It aims to recover the fissile material and to separate the minor actinides from fission products. The reprocessing involves several chemical steps based on redox and acido-basic properties of the various elements contained in the fuel salt. One challenge is to perform a selective extraction of actinides and lanthanides in spent liquid fuel. Extraction of actinides and lanthanides are successively performed by a reductive extraction in liquid bismuth pool containing metallic lithium as a reductive reagent. The objective of this paper is to give a description of the several steps of the reprocessing retained for the molten salt fast reactor (MSFR) concept and to present the initial results obtained for the reductive extraction experiments realized in static conditions by contacting LiF-ThF4-UF4-NdF3 with a lab-made Bi-Li pool and for which extraction efficiencies of 0.7% for neodymium and 14.0% for uranium were measured. It was concluded that in static conditions, the extraction is governed by a kinetic limitation and not by the thermodynamic equilibrium.
Źródło:
Nukleonika; 2015, 60, No. 4, part 2; 907-914
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Protective effects of quercetin on cadmium fluoride induced oxidative stress at different intervals of time in mouse liver
Autorzy:
Zargar, Seema
Siddiqi, Nikhat
Al Daihan, Sooad
Wani, Tanveer
Powiązania:
https://bibliotekanauki.pl/articles/1039092.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
cadmium fluoride
quercetin
oxidative stress
flavonoids
histology
adverse effect
Opis:
Quercetin, a member of the flavonoid family is a major antioxidant acquired in humans by food consumption, while Cadmium fluoride (CdF2) is one of the naturally occurring chemicals having adverse effects. The protective effect of quercetin on time dependent oxidative damage induced in mice liver by CdF2 was studied in the following groups of mice consisting of six mice each: (i) control group; (ii) mice treated with single i.p injection of 2 mg/kg bw CdF2 for 24 h; (iii) mice treated with single i.p injection of 2 mg/kg bw CdF2 for 48 h; (iv) mice treated with single i.p injection of quercetin (100 mg/kg bw); (v) mice treated with i.p injection of 100 mg/kg bw of quercetin followed by i.p injection of CdF2 (2 mg/kg bw) for 24 h; and (vi) mice treated with i.p injection of 100mg/kg bw of quercetin followed by CdF2 (2 mg/kg bw) for 48 h. Administration of quercetin two hours before CdF2 significantly reduced the biochemical alterations in reduced glutathione, ascorbic acid, lipid peroxidation, super oxide dismutase, catalase and total protein (p<0.05). Histopathology also showed the protective effect of quercetin. The livers treated with CdF2 were atrophic, markedly nodular, inflamed and necrotic. However, this effect was reduced to a minimum in the mice pre-treated for two hours with quercetin.
Źródło:
Acta Biochimica Polonica; 2015, 62, 2; 207-213
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gamma-Irradiations Effects on Structural and Micro-Structural Parameters of Chromium(III) – Silicate Base Mica Clay
Autorzy:
Elsabawy, Khaled M.
Abou-Sekkinaa, Morsy M.
Powiązania:
https://bibliotekanauki.pl/articles/1186742.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Free fluoride
Mica clay
SEM
Structural Parameters
Synthesis
XRD
Opis:
Solution route was applied to synthesize new family of free-fluoride synthetic clay. All starting solutions were made by applying carbon tetra-chloride (CCl4) as a solvent. The selected sample of synthetic free fluoride – Na-4-mica was having the general formula (Na4Mg6M4Si4O22•nH2O) where M = Cr3+ was exposured to two different ɤ-irradiation doses 1st dose = 1.5 MR/h and 2nd dose = 3 MR/h at 25 cm distance. Structural parameters such as lattice constants, volume and phase quality were monitoring carefully by using both of XRD and SEM evaluating grain size of the mica bulk. Structural investigations proved that Cr-clay exhibits monoclinic phase accompanied with structure quality in comparison with both of Bi-and Al-clays
Źródło:
World Scientific News; 2016, 32; 13-23
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kinetic Study on the Preparation of Aluminum Fluoride Based on Fluosilicic Acid
Autorzy:
Chen, Gaoxiang
Yang, Xingdong
Qu, Jiyan
Luo, Jianhong
Zhang, Zhiye
Sun, Lan
Powiązania:
https://bibliotekanauki.pl/articles/1849322.pdf
Data publikacji:
2021
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
kinetic study
fluosilicic acid
aluminum fluoride
uncreated-core model
Opis:
Reasonable mathematical derivation and mechanism model in the process of producing aluminum fluoride by fluosilicic acid is the key to the industrial treatment of fluorine resources in the tail gas of phosphate ore. In this work, aluminum fluoride was generated directly by fluosilicic acid to extract fl uorine from the tail gas of phosphate rock. The uncreated-core model dominated by interfacial reaction and the uncreated-core model dominated by internal diffusion-reaction were then respectively utilized to describe the reaction kinetics of the generation of aluminum fluoride. The result showed that the uncreated-core model was dominated by interface reaction and internal diffusion, the apparent reaction order n = 1, and the activation energy Ea = 30.8632 kJ . mol–1. Product characterization and kinetic analysis were employed to deduce the reaction mechanism of preparing aluminum fluoride. The theoretical basis for the low-cost recycling of fluorine resources in the tail gas of industrial phosphate ore was provided in this work.
Źródło:
Polish Journal of Chemical Technology; 2021, 23, 3; 10-16
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication of fluoride nanocrystals and their spectroscopic properties
Autorzy:
Pawlik, N.
Szpikowska-Sroka, B.
Goryczka, T.
Pisarski, W. A.
Powiązania:
https://bibliotekanauki.pl/articles/173278.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
sol-gel method
glass-ceramics
fluoride nanocrystals
europium ions
Opis:
In this work, the fabrication of glass-ceramic materials containing MF3:Eu3++ (M = La, Gd) nanocrystals dispersed in silica sol-gel hosts has been presented. The transformation from liquid sols towards bulk samples was also examined based on IR measurements. The crystallization temperatures and formation of MF3 phases were verified based on TG/DSC analysis and XRD measurements. The optical properties of prepared Eu3+5D05D0 → 7FJ (J = 1–4) emission bands, which were recorded within the reddish-orange spectral area under near-UV illumination (λexc = 393 nm). Recorded luminescence spectra and double-exponential character of decay curves for prepared glass-ceramic samples indicated the successful migration of Eu3+ dopant ions from amorphous silica framework to low-phonon energy MF3 nanocrystal phases.
Źródło:
Optica Applicata; 2019, 49, 3; 415-426
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ stężenia jonów fluorkowych na wzrost orientowanych nanorurek tlenkowych na powierzchni stopu tytanowegoTi-6Al-7Nb
Fluoride concentration effect on the anodic growth of self aligned oxide nanotube array on Ti-6Al-7Nb
Autorzy:
Kaczmarek, A.
Głazowska, I.
Krasicka-Cydzik, E.
Powiązania:
https://bibliotekanauki.pl/articles/285145.pdf
Data publikacji:
2010
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
jony fluorkowe
nanorurki
stopy tytanu
fluoride
nanotubes
titanium alloys
Opis:
W pracy przedstawiono formowanie nanorurek TiO2 na stopie Ti-6Al-7Nb w 1M H3PO4z dodatkiem niewielkich ilości jonów fluorkowych. Na jakość otrzymywanych przez anodowanie nanorurek wpływają parametry takie jak: potencjał, czas anodowania, stężenie jonów fluorkowych w roztworze, szybkość narastania potencjału, przy czym wartości dwóch ostatnich parametrów wydają się być kluczowymi i odpowiedzialnymi za morfologię oraz strukturę otrzymywanych warstw. W badaniach skoncentrowano uwagę na wpływie jonów fluorkowych na przebieg anodowania dwufazowego stopu implantowego (α+β) Ti-6Al-7Nb. Proces formowania polegał na polaryzacji próbek do 20 V z szybkością narastania potencjału 500 mV/s w 1M H3PO4z dodatkiem 0,2; 0,3; 0,4% wag. HF, oraz utrzymaniu próbki w tych warunkach przez 2h. W rezultacie otrzymano powierzchnię nanorurek o średnicach od 50 do 80 nm na fazie α oraz o grubszych ściankach na fazie β. Proces elektrochemicznego formowania obejmował dwa etapy: pierwszy potencjodynamiczny oraz drugi potencjostatyczny (20 V).Podczas ich trwania zarejestrowano różne charakterystyki prądowe dla opisywanych stężeń jonów fluorkowych. Z przeprowadzonych badań wynika jednoznaczna zależność pomiędzy najwyższą wartością prądu zarejestrowaną w etapie potencjodynamicznym a średnicą nanorurek otrzymywanych podczas anodowania przy udziale 0,3% wag. HF, fakt ten jest tłumaczony obecnością pierwiastków stopowych oraz transportem jonów w warstwie tlenkowej.
The formation of nanotube oxide layers on Ti-6Al-7Nb alloy in H3PO4 acid solutions containing fluoride ions is presented. Among several parameters influencing the quality of nanotubes formed anodically such as potential, time of anodizing, fluoride ions concentration and scan rate of polarization, particularly the last two seem to be the most responsible for nanotubes structure and morphology. The effect of fluoride ions concentration on the morphology of nanotubes on the two phase (α+β) Ti-6Al-7Nb implant alloy has been evaluated in our work. The formation of nanotubes was performed by polarizing of the Ti-6Al-7Nb alloy samples in 1M H3PO4containing 0.2, 0.3 and 0.4 wt% HF to 20 V using scan rate 500 mV/s and then holding them at that potential for further 2h in the same electrolyte. Nanotubes of diameter ranging from 50 nmto 80 nm, with thicker walls over β-phase grains than over α-phase grains, were obtained. During the formation process, which includes two stages: the first potentiodynamic and the second potentiostatic (20 V),different electrochemical behaviour was observed in electrolytes of various fluoride concentration. The clear relationship between the highest currents and the biggest diameter of nanotubes for 0.3 wt% HF containing electrolyte observed during the first stage of anodizing is explained with regard to electrochemical characteristics of alloying elements and transport of electrolyte anions in oxide layers.
Źródło:
Engineering of Biomaterials; 2010, 13, 92; 18-23
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Otrzymywanie ceramiki przezroczystej z CaF2 z wykorzystaniem techniki Hot Isostatic Pressing-HIP
Fabrication of CaF2 transparent ceramics using Hot Isostatic Pressing-HIP
Autorzy:
Perkowski, K.
Gizowska, M.
Zalewska, M.
Kobus, I.
Konopka, G.
Osuchowski, M.
Witosławska, I.
Powiązania:
https://bibliotekanauki.pl/articles/168042.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Ceramiki i Materiałów Budowlanych
Tematy:
ceramika przezroczysta
fluorek wapnia
HIP
transparent ceramics
calcium fluoride
Opis:
W niniejszej publikacji przedstawiono badania dotyczące otrzymywania przezroczystej ceramiki z fluorku wapnia. W pracy zastosowano dwa rodzaje proszku CaF2, które zostały scharakteryzowane pod względem składu fazowego metodą XRD, morfologii przy użyciu elektronowego mikroskopu skaningowego, wielkości cząstek, a także pod względem stabilności termicznej metodą DTA-TG do 600ºC w atmosferze powietrza syntetycznego. Pierwszy z proszków firmy Sigma-Aldrich charakteryzował się średnim rozmiarem cząstek/aglomeratów Dv50 na poziomie 20,3 μm, natomiast proszek firmy ABCR odznaczał się większym/szerszym rozkładem cząstek, a Dv50 wynosiła 8,9 μm. Oba proszki wykazują silną aglomerację, co zostało potwierdzone w trakcie badań za pomocą SEM. Rentgenowska analiza fazowa wykazała obecność fazy regularnej w przypadku obu proszków. Badanie termograwimetryczne wykazało dla drobniejszego proszku fluorku wapnia (firmy ABCR) obecność zanieczyszczenia, które zostało zanalizowane jako pozostałość węgla po syntezie. Oba surowce były spiekane w zakresie temperatur 900–1350ºC w atmosferze argonu lub próżni. Dodatkowo próbki były dogęszczane w wysokotemperaturowej prasie izostatycznej przy ciśnieniu argonu wynoszącym 2000 barów i temperaturze 1300ºC. W artykule przedstawiono rezultaty badań przewodnictwa cieplnego materiału domieszkowanego (2%at. Yb), jak i nie domieszkowanego fluorku wapnia. W pracy przedstawiono widma fluorescencyjne próbek CaF2 domieszkowanych fluorkiem iterbu w ilości 2% at.
The paper presents the research on obtaining a transparent ceramics made from calcium fluoride. The researchers used two types of calcium fluoride powders which were characterized by XRD (phase content), SEM (microstructure), grain size analysis and thermal analysis DTA-TG, with temperature up to 600ºC in atmosphere of synthetic air, so as to define a temperature of decomposition. The raw materials used were different in terms of grain size. Powder (under symbol C1) provided by Sigma-Aldrich has an average grain/agglomerate size Dv 50 at the level of 20,3 μm, whereas powder (under symbol C2) provided by ABCR has a wider range of grain/agglomerate size distribution and Dv 50 was 8,9 μm. A strong tendency to agglomeration was proved by SEM analysis. X-ray phase analysis indicated a cubic phase in case of both powders. Differences between materials were noticed during thermogravimetric analysis, where for powder provided by ABCR some contamination was observed, which was analyzed as residual carbon after synthesis. For the purpose of further research, cylindrical samples were obtained by die-pressing method from both powders and sintered in temperature range of 900–1350ºC, in protective atmosphere of argon or vacuum. Additionally, the samples were densificated by hot isostatic pressing under pressure of 2000 bar of argon and temperature 1300ºC. The results of thermal conductivity and fluoresces spectrum of raw calcium fluoride and doped with ytterbium (2% at.) were shown in this paper.
Źródło:
Szkło i Ceramika; 2016, R. 67, nr 4, 4; 19-23
0039-8144
Pojawia się w:
Szkło i Ceramika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Serum fluoride levels in ambulance staff after commencement of methoxyflurane administration compared to meta-analysis results for the general public
Autorzy:
Allison, Serah J.
Docherty, Paul D.
Pons, Dirk
Chase, James G.
Powiązania:
https://bibliotekanauki.pl/articles/2093863.pdf
Data publikacji:
2021-12-13
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
meta-analysis
prospective studies
fluorides
ambulances
fluoride poisoning
methoxyflurane
Opis:
ObjectivesAmbulance officers administering methoxyflurane as an inhalational analgesic may be exposed to trace vapor. Fluoride is a methoxyflurane metabolite, and has been associated with acute renal failure in anesthesia patients and skeletal fluorosis with chronic elevated serum levels from other sources. However, there has been no direct measurement of serum fluoride in occupationally exposed ambulance officers. Thus, this study directly measures serum fluoride over a prolonged period in order to determine renal toxic and skeletal fluorosis risk to ambulance officers who are administering methoxyflurane.Material and MethodsSerum inorganic fluoride concentrations were measured in a prospective observational study of 12 emergency medical technicians (EMTs). The study took 7 serum fluoride measurements over 24 months. A meta-analysis of healthy adult serum fluoride ranges was also conducted.ResultsThe typical healthy adult serum fluoride range was determined to be 0.21–2.11 μmol/l (p < 0.001). The EMTs’ baseline median (IQR) serum fluoride concentrations were 0.4 μmol/l (0.2; 1.0) with maximum 1.6 μmol/l. The EMTs’ overall median serum fluoride was 0.4 μmol/l (0.2; 1.3) with maximum 4.0 μmol/l, usually within healthy reference ranges. All results were ≤10% of the suggested single-dose renal toxic threshold. One result was above a threshold for skeletal fluorosis. The highest measured serum fluoride was 24% of the lowest level associated with radiologic evidence of fluorosis. There was no evidence overall of increasing serum fluoride levels.ConclusionsThere was no evidence that EMTs’ exposure to methoxyflurane resulted in sustained increased serum fluoride. These results imply EMTs’ occupational safety from acute renal toxicity when activated carbon filtration is used on patient exhalation. However, 1 serum fluoride result above a skeletal fluorosis threshold suggests that the risk of mild skeletal fluorosis cannot be excluded.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2021, 34, 6; 767-777
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Seasonal variation in fluoride content in groundwaters of Langtang area, Northcentral Nigeria
Autorzy:
Dibal, H. U.
Dajilak, W. N.
Lekmang, I. C.
Nimze, L. W.
Yenne, E. Y.
Powiązania:
https://bibliotekanauki.pl/articles/100834.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Śląski. Wydział Nauk o Ziemi
Tematy:
wody gruntowe
fluorek
fluoroza
warstwa wodonośna
groundwater
fluoride
fluorosis
aquifer
Opis:
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.
Źródło:
Contemporary Trends in Geoscience; 2017, 6, 1; 11-27
2299-8179
Pojawia się w:
Contemporary Trends in Geoscience
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure and surface energy of both fluorite halves after cleaving along selected crystallographic planes
Autorzy:
Janicki, M. J.
Drzymala, J.
Kowalczuk, P. B.
Powiązania:
https://bibliotekanauki.pl/articles/110167.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fluorite
fluoride
surface energy
interfacial energy
cleaving
reorganization
surface ions
Opis:
The density functional theory, supported with a commercial software, was used to compute the geometry and surface energy of fluorite cleaved along the (111), (110) and (100) planes. In the case of cleaving a piece of fluorite along the (111) plane the two newly created surfaces are identical consisting of fluorite ions with the surface energy equal to 0.384 J/m2. Cleaving fluorite along the (110) plane also provides identical halves and, both contain one Ca ion next to two F ions, with the surface energy equal to 0.723 J/m2. When cleaving takes place along the (100) plane, it creates two corresponding halves with different surface structures. One half, having only surface Ca ions (100Ca) has the surface energy equal to 0.866 J/m2, while the surface energy of the second half, having only F surface ions (100F), is 0.458 J/m2. Different structures and energies of the corresponding fluorite surfaces, that is (100Ca) and (100F) planes, should have an impact on their chemical properties, including hydrophobicity expressed by contact angle. The calculations performed in the paper also showed that reorganization of fluorite surfaces after cleaving was insignificant for all of the investigated planes.
Źródło:
Physicochemical Problems of Mineral Processing; 2016, 52, 1; 451-458
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nanocolloidal Ru/MgF2 Catalyst for Hydrogenation of Chloronitrobenzene and Toluene
Autorzy:
Pietrowski, M.
Zieliński, M.
Wojciechowska, M.
Powiązania:
https://bibliotekanauki.pl/articles/779536.pdf
Data publikacji:
2014
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
ruthenium nanocolloidal catalyst
magnesium fluoride
toluene hydrogenation
reduction of chloronitrobenzene
Opis:
The use of magnesium fluoride support for ruthenium active phase allowed obtaining new catalysts of high activities in the hydrogenation of toluene and ortho-chloronitrobenzene. Ruthenium colloid catalysts (1 wt.% of Ru) were prepared by impregnation of the support with the earlier produced polyvinylpyrrolidone (PVP)-stabilized ruthenium colloids. The performances of the colloidal catalysts and those obtained by traditional impregnation were tested in the reactions of toluene hydrogenation to methylcyclohexane and selective hydrogenation of ortho-chloronitrobenzene (o-CNB) to ortho-chloroaniline (o-CAN). It was shown that the use of chemical reduction method allows obtaining highly monodisperse ruthenium nanoparticles of 1.6–2.6 nm in size. After reduction in hydrogen at 400oC, the colloidal ruthenium nanoparticles were found to strongly interact with MgF2 surface (SMSI), which decreased the catalyst ability to hydrogen chemisorption, but despite this, the colloid catalysts showed higher activity in o-CNB hydrogenation and higher selectivity to o-CAN than the traditional ones. It is supposed that their higher activity can be a result of high dispersion of Ru in colloid catalysts and the higher selectivity can be a consequence of the lower availability of hydrogen on the surface.
Źródło:
Polish Journal of Chemical Technology; 2014, 16, 2; 63-68
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Removal of fluoride ions by ultrafiltration in the presence of cationic surfactants
Autorzy:
Klimonda, A.
Grzegorzek, M.
Majewska-Nowak, K.
Powiązania:
https://bibliotekanauki.pl/articles/208133.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
ultrafiltration
fluoride ions
surfactant
membrane
ultrafiltracja
jony fluorkowe
fluor
surfaktanty
membrany
Opis:
The usability of surfactant-aided ultrafiltration for removal of fluoride ions from aqueous solutions has been investigated. The experiments were conducted with the use of cellulose and polyethersulfone membranes. Fluoride solutions containing 10 and 100 mg F–/dm3 and cationic surfactants: octadecylamine acetate (ODA) and hexadecylpyridium chloride (CPC) were used in the experiments. The concentration of surfactants amounted to 320–960 mg/dm3. Ultrafiltration process was run under a trans-membrane pressure of 0.2 MPa. In the course of experiments, the effects of initial fluoride concentration, surfactant concentration and membrane type on the fluoride retention coefficient as well as the permeate flux were studied. It was found that the increase of the surfactant concentration effected in improvement of the separation efficiency. On contrary, the permeate flux decreased upon increase of the surfactant concentration. The process efficiency was also strongly influenced by the membrane and surfactant type. The permissible concentration of fluoride in the final product (below 1.5 mg F–/dm3) was obtained for the test with initial solutions containing 10 mg F–/dm3, polyethersulfone membrane and CPC con-centration equal to 644 and 966 mg/dm3.
Źródło:
Environment Protection Engineering; 2017, 43, 2; 5-13
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The role of fluorine-containing ultra-thin layer in controlling boron thermal diffusion into silicon
Autorzy:
Kalisz, M.
Beck, R. B.
Barcz, A.
Ćwil, M.
Powiązania:
https://bibliotekanauki.pl/articles/308657.pdf
Data publikacji:
2007
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
fluorine
reactive ion etching
silicon fluoride
boron thermal diffusion
fluorocarbon plasma
Opis:
We have investigated the influence of silicon dioxide reactive ion etching (RIE) parameters on the composition of the polymer layer that is formed during this process on top of the etched layer, and finally, the role of this layer in high-temperature thermal diffusion of boron into silicon. The polymeric layer formed on the etched surface appeared to consist of fluorine and silicon fluoride (SiOF and SiF). Concentration of these components changes depending on the parameters of RIE process, i.e., rf power, gas pressure and etching time. The composition of this polymeric layer affects, in turn, boron thermal diffusion into silicon. With increasing rf power, the depth of boron junction is increased, while increasing time of etching process reduces boron diffusion into silicon.
Źródło:
Journal of Telecommunications and Information Technology; 2007, 3; 25-29
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
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