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Wyszukujesz frazę "Zn" wg kryterium: Temat


Wyświetlanie 1-6 z 6
Tytuł:
Circuit heavy metals in nature
Autorzy:
Draszawka – Bołzan, Beata
Cyraniak, Emil
Powiązania:
https://bibliotekanauki.pl/articles/1194065.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Cd
Cu
Pb
Zn
anthropogenic emissions
heavy metals
Opis:
The problem of environmental pollution with heavy metals is still serious, despite numerous activities related to the reduction of anthropogenic emissions of these elements into the environment. There is a growing concentration of many toxic metals in soils and vegetation (remaining in close relation with the state of air quality), and especially in the environment of large urban agglomerations. The paper presents an assessment of the degree of contamination of soil and grass vegetation with heavy metals (Zn, Pb, Cu, Cd) in the vicinity of the communication over Warsaw. Research material obtained from the same locations (samples of soil and grass vegetation) was analyzed (AAS) in terms of the total concentration of metals in soils and its mobile form, while in plants is the total concentration of the corresponding trace the AAS atomic spectrometry. Based on the concentrations of metals in soil and vegetation samples were determined bioaccumulation factors. Methods mobile metals isolated by selective extraction of a 0.05 M EDTA solution. The results obtained were related to the results of similar research conducted two years earlier in 2005. Additionally the effect of leaching of soluble forms of metal particulate pollutants deposited on the surface of vegetation.
Źródło:
World Scientific News; 2014, 4; 10-16
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect on magnetic properties of zinc doped nano ferrites synthesized by precursor or metod
Autorzy:
Anjaneyulu, T.
Murthy, P. N.
Rafi, Sk. Md.
Bademiya, Sk.
John, G. S.
Powiązania:
https://bibliotekanauki.pl/articles/412213.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Nanoferrites
Cu-Zn ferrite
Precursor Method
Magnetic properties
Opis:
Nanocrystalline Cu-Zn ferrites have been synthesized using precursor method. Cu-Zn ferrites were formed at low temperature without any impurities. The particle sizes were observed to decrease from 60 nm to 50 nm with increasing non-magnetic Zn doping. Cu is used to decrease the sintering temperature. The X-ray diffraction (XRD) and IR analysis of Cu-Zn revealed the formation of Single-Phase Spinel structure at very low annealing temperature. The particle sizes observed from XRD is very well in agreement with SEM analysis. Cu-Zn ferrite nanoparticles were observed to be dependent on the particle size. Saturation (Ms) and Remanence (Mr) magnetization of ferrites increases due to the modifications occurred among the A-B, A-A and B-B interactions of Spinel structure. The Coercive force (Hc) decreases with increase of Zn ions concentration.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 14; 37-43
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical dispersion characterization of sprayed Zn1-xMnxO thin films
Autorzy:
Habubi, N.F.
Chiad, S.S.
Oboudi, S.F.
Toma, Z.A.
Powiązania:
https://bibliotekanauki.pl/articles/411575.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
TCOs
Dispersion parameters
spray pyrolysis
zinc oxide
Zn1-xMnxO
Opis:
Uniform and adherent Zn1-xMnxO films have been deposited by using spray pyrolysis technique on glass substrates. The optical properties and dispersion parameters of zinc oxide have been studied as a function of doping concentration with Mn. Changes in direct optical energy band gap of cobalt oxide films were confirmed after doping, The optical energy gap Eg increased from 3.13 eV for the undoped ZnO to 3.39 eV with increasing the doping concentration of Mn to 4%. The changes in dispersion parameters and Urbach tails were investigated. An increase in the doping concentration causes a decrease in the average oscillator strength. The single-oscillator parameter has been reported.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 4; 1-8
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heavy metal toxicity - metabolism, absorption, distribution, excretion and mechanism of toxicity for each of the metals
Autorzy:
Magelsir, Hassan Mohamed Ihmed
Powiązania:
https://bibliotekanauki.pl/articles/1119309.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Cd
Cu
Fe
Heavy metals
Hg
Ni
Pb
Zn
growth
nutrients
proteins
uptake
Opis:
The main threats to human health from heavy metals are associated with exposure to lead, cadmium, mercury and arsenic. These metals have been extensively studied and their effects on human health regularly reviewed by international bodies such as the WHO. Heavy metals have been used by humans for thousands of years. Although several adverse health effects of heavy metals have been known for a long time, exposure to heavy metals continues, and is even increasing in some parts of the world, in particular, in less developed countries. However, over the last 100 years, emissions have declined in most developed countries. Cadmium compounds, the exception, are currently mainly used in re-chargeable nickel-cadmium batteries. Cadmium emissions have increased dramatically during the 20th century, one reason being that cadmium-containing products are rarely re-cycled, but often dumped together with household waste. Cigarette smoking is a major source of cadmium exposure. In non-smokers, food is the most important source of cadmium exposure. Recent data indicate that adverse health effects of cadmium exposure may occur at lower exposure levels than previously anticipated, primarily in the form of kidney damage, but possibly also in bone effects and fractures. Many individuals in Europe already exceed the recommended exposure levels and the margin is very narrow for large groups. Therefore, measures should be taken to reduce cadmium exposure in the general population in order to minimize the risk of adverse health effects. The general population is primarily exposed to mercury via food, fish being a major source of methyl mercury exposure, as is dental amalgam. The general population, however, does not face a significant health risk from methyl mercury, although certain groups with high fish consumption may attain blood levels associated with a low risk of neurological damage to adults. Since there is a risk to the fetus in particular, pregnant women should avoid a high intake of certain fish, such as shark, swordfish and tuna; fish (such as pike, walleye and bass) taken from polluted fresh waters should especially be avoided. There has been a debate on the safety of dental amalgams and claims have been made that mercury from amalgam may cause a variety of diseases. However, there are no studies so far that have been able to show any associations between amalgam fillings and ill health. The general population is exposed to lead from air and food in roughly equal proportions. During the last century, lead emissions to ambient air caused considerable pollution, mainly due to lead emissions from petrol. Children are particularly susceptible to lead exposure due to high gastrointestinal uptake and the permeable blood-brain barrier. Blood levels in children should be reduced below the levels so far considered acceptable as recent data indicates that lead may hold neurotoxic effects at lower levels of exposure than previously anticipated. Although lead in petrol has dramatically decreased over the last decades, thereby reducing environmental exposure, phasing out any remaining uses of lead additives in motor fuels should be encouraged. The use of lead-based paints should also be abandoned, and lead should not be used in food containers. In particular, the public should be aware of glazed food containers, which may leach lead into food. Exposure to arsenic is mainly via intake of food and drinking water, food being the most important source in most populations. Long-term exposure to arsenic in drinking water is mainly related to increased risks of skin cancer, but also enhanced risk of some other cancers, as well as other skin lesions such as hyperkeratosis and pigmentation changes. Occupational exposure to arsenic, primarily by inhalation, is causally associated with lung cancer. Clear exposure-response relationships and high risks have been observed.
Źródło:
World News of Natural Sciences; 2016, 4; 20-32
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SEM and EDS studies of porous coatings enriched in calcium and zinc obtained by PEO with ramp voltage
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Pietrzak, Kornel
Powiązania:
https://bibliotekanauki.pl/articles/1178366.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
CP Titanium Grade 2
Micro Arc Oxidation (MAO)
Plasma Electrolytic Oxidation (PEO)
calcium nitrate Ca(NO3)2∙4H2O
linear polarization
ramp voltage
zinc nitrate Zn(NO3)2∙6H2O
Opis:
In this work, the SEM and EDS results of porous and enriched in calcium or zinc coatings, which were obtained during 3-minute treatments using Plasma Electrolytic Oxidation (Micro Arc Oxidation) processes on CP Titanium Grade 2 at ramp potentials (linear polarization) from 0 up to 650 VDC in electrolytes containing 500 g Ca(NO3)2∙4H2O and/or 500 g Zn(NO3)2∙6H2O in 1 L H3PO4, are presented. It was found that obtained coatings have pores with different shapes and diameters. The Ca/P and Zn/P ratios by atomic concentration are the same and equal to 0.2, what may suggest hydroxyapatite-like structure (M,Ti)x(PO4)y, where M = {Ca, Zn}.
Źródło:
World Scientific News; 2017, 77, 2; 242-255
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Porous PEO coatings on titanium, obtained under DC regime, enriched in magnesium, calcium, zinc, and copper
Autorzy:
Rokosz, Krzysztof
Hryniewicz, Tadeusz
Pietrzak, Kornel
Dudek, Łukasz
Powiązania:
https://bibliotekanauki.pl/articles/1156239.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
plasma electrolytic oxidation (peo)
micro arc oxidation (mao)
cp titanium grade 2
calcium nitrate ca(no3)2•4h2o
magnesium nitrate mg(no3)2∙6h2o
zinc nitrate zn(no3)2∙6h2o
copper nitrate cu(no3)2∙3h2o
Opis:
In the present paper, the analysis of SEM and EDS results of porous and enriched in calcium, magnesium, zinc, copper and phosphorus coatings, obtained during 3-minute treatments performed by Plasma Electrolytic Oxidation (PEO)/Micro Arc Oxidation (MAO) processes on CP Titanium Grade 2, is presented. The PEO process was carried out at DC potentials of 500 VDC, 575 VDC, and 650 VDC in electrolytes containing 125 g Ca(NO3)2•4H2O, and 125 g Mg(NO3)2∙6H2O, and 125 g Zn(NO3)2∙6H2O, and 125 g Cu(NO3)2∙3H2O in 1 L H3PO4. It was found that obtained coatings have pores with different shapes and diameters and/or size/dimentions. The Ca/P, Mg/P, Zn/P, Cu/P, and M/P ratios (M=Ca+Mg+Zn+Cu) were equal to 0.074, 0.046, 0.056, 0.042, and 0.218, respectively. The highest value of each of these ratios was recorded for 650 VDC. It may be concluded that the obtained PEO coatings structures most likely are similar to hydroxyapatite-like structures, in which the Ca2+ may be replaced with Zn2+, Mg2+, Cu2+.
Źródło:
World Scientific News; 2018, 94, 2; 99-114
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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