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Wyszukujesz frazę "reduction process" wg kryterium: Wszystkie pola


Tytuł:
Mössbauer Study of a Reduction Process in Iron Azaporphyrins
Autorzy:
Kaczmarzyk, T.
Jackowski, T.
Dziliński, K.
Kania, L.
Powiązania:
https://bibliotekanauki.pl/articles/1808101.pdf
Data publikacji:
2009-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
33.15.-e
Opis:
Electronic structure of the Fe(II)- and Fe(I)-complexes of mono- and diazaporphyrins studied by the Mössbauer spectroscopy is considered in this paper. It was found that in the presence of tetrahydrofuran molecules, the electron configuration of Fe(II) ions in the studied complexes corresponds to the intermediate spin state (S = 1) and the complexation of tetrahydrofuran solvent does not change this state. Interaction of tetrahydrofuran solvent with Fe(I)-azaporphyrins does not influence the electronic structure of Fe(I) ions coordinated to the porphyrin ligand, either. Electron configuration of Fe(I) ions in Fe(I)-octaethylporphyrins and Fe(I)-azaporphyrins is the same: ($d_{xy})^{2}(d_{xz},d_{yz})^{4}(d_{z}^2)^{1}$. The aza substitution is reflected in the values of the Mössbauer parameters. Increasing number of nitrogen atoms at meso positions causes the increase in the quadrupole splittings within the range 1.49-2.24 mm/s for the Fe(II) complexes and within the range 1.35-1.85 mm/s for the Fe(I)-porphyrins. Values of the isomer shifts are decreased from 0.51 to 41 mm/s for the same sequence of the Fe(II) complexes. For the Fe(I) reduced forms the isomer shifts are nearly constant and equal to about 0.37 mm/s. The Mössbauer results are discussed in association with EPR data for Fe(I)-porphyrins.
Źródło:
Acta Physica Polonica A; 2009, 115, 3; 656-659
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Reduction Process on the Iron-Molybdenum Nanoparticles in Modified MCM-41 Silica
Autorzy:
Surowiec, Z.
Wiertel, M.
Gac, W.
Budzyński, M.
Powiązania:
https://bibliotekanauki.pl/articles/1381974.pdf
Data publikacji:
2014-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.80.+y
78.67.Bf
78.67.Rb
75.20.-g
Opis:
Iron-molybdenum silica mesoporous materials were obtained by the application of direct hydrothermal method. The influence of high temperature samples reduction in the $H_2$ flow on their structural and magnetic properties was studied. Four samples with different metal contents relative to silica were investigated. The study was carried out by means of X-ray diffraction, $\text{}^{57}Fe$ Mössbauer spectroscopy and the temperature programmed reduction method. With an increasing metals content, primary pores of MCM-41 transformed into the bottle-like pores, and then into the slit-like ones. Reduction and heat treatment caused the α-Fe, $Fe_2Mo$, and Fe-Mo alloy formation. Iron and molybdenum atoms after being released into the silica matrix, where they were embedded, create clusters or crystallites. It was observed that the high temperature reduction caused partial transformation of highly dispersed Fe-Mo oxides species initially embedded in silica walls into crystallites big enough to give magnetic sextet component in the Mössbauer spectra.
Źródło:
Acta Physica Polonica A; 2014, 125, 3; 846-849
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative Studies on a Chamfer Technology and a Convex Roll Technology During the Soft Reduction Process
Autorzy:
Zong, Nanfu
Jing, Tao
Liu, Yang
Powiązania:
https://bibliotekanauki.pl/articles/2049345.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
convex roll technology
chamfer technology
deformation behavior
cracking risk
Opis:
To comprehensively investigate the diversity of a chamfer technology and a convex roll technology under the same soft reduction process (i.e., section size, reduction amount, casting speed and solid fraction), a three-dimensional mechanical model was developed to investigate the effect of the chamfer profile and roll surface profile on the deformation behavior, cracking risk, stress concentration and reduction force of as-cast bloom during the soft reduction process. It was found that a chamfer bloom and a convex roll can both avoid the thicker corner of the as-cast bloom solidified shell, and significantly reduce reduction force of the withdrawal and straightening units. The convex profile of roll limits lateral spread along bloom width direction, therefore it forms a greater deformation to the mushy zone of as-cast bloom along the casting direction, the tensile strain in the brittleness temperature range (BTR) can obviously increase to form internal cracks. The chamfer bloom is much more effective in compensating the solidification shrinkage of mushy zone. In addition, chamfer bloom has a significant decrease of tensile strain in the brittleness temperature range (BTR) areas, which is expected to greatly reduce the risk of internal cracks.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 3; 819-829
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectroscopic characteristics of FeI-phthalocyanine
Autorzy:
Kaczmarzyk, T.
Jackowski, T.
Dziliński, K.
Powiązania:
https://bibliotekanauki.pl/articles/148333.pdf
Data publikacji:
2007
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
iron phthalocyanine
reduction process
Mössbauer spectroscopy
EPR
DTF
Opis:
Results of Mössbauer and EPR study of a univalent-iron phthalocyanine complex (FeIPc) are presented in this paper. FeIPc has been obtained from FeIIPc by the chemical reduction method in tetrahydrofuran (THF) and dimethoxyethan (DME) solutions. Like in the case of FeI-porphyrin complexes, Mössbauer and EPR data as well as quantum calculations of electronic absorption spectra confirm in this case a low-spin configuration of FeI ions with an unpaired electron located at dz2 orbital. Interaction between FeIPc and THF molecules does not change significantly the electron configuration of FeI ions coordinated to phthalocyanine ligand.
Źródło:
Nukleonika; 2007, 52, supl. 1; 99-103
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of NaCl Additive on the Reduction Process of MoO3 to Mo2C by High-Purity CO Gas
Autorzy:
Que, Biao-Hua
Wang, Lu
Wang, Bao
Chen, Yi
Xue, Zheng-Liang
Powiązania:
https://bibliotekanauki.pl/articles/2106609.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Mo2C
MoO3
CO
NaCl
Opis:
In this work, influence of NaCl additive on the transformation process of MoO3 to Mo2C under pure CO atmosphere in the range of room temperature to 1170 K was investigated. The results showed that transformation of MoO3 to Mo2C can be roughly divided into two stages: the reduction of MoO3 to MoO2 (the first stage) and the carburization of MoO2 to Mo2C (the second stage). As to the first stage, it was found that increasing the content of NaCl (from 0 to 0.5 wt.%) was beneficial for the increase of reaction rate due to the nucleation effect; while when the content of NaCl increased to 2 wt.%, the reaction rate will be decreased in turn. As to the second stage, the results showed that reaction rate was decreased with the increase of NaCl, which may be due to the formation of low-melting point eutectic. The work also found that morphology of as-prepared Mo2C was irregular and particle size of it was gradually increased with increasing the NaCl content. According to the results, the possible reaction mechanism was proposed.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 2; 787--796
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical investigation of heat exchange in rotary furnace
Autorzy:
Kolczyk, E.
Miczkowski, Z.
Czernecki, J.
Powiązania:
https://bibliotekanauki.pl/articles/354348.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
numerical simulation
heat exchange
rotary furnace
slag reduction process
Opis:
Process of heat exchange in a rotary furnace during converter slag reduction was modelled.Temperature distribution in the furnace and temperature of the charge (slag) only were examined. Influence of modification of the process gas supply method by changing the number of nozzles on the course of the reduction process was analyzed. It has been found out that application of a nozzle as a submerged flame burner provides possibilities to reach higher charge temperature. Application of more nozzles in the process of converter slag reduction can increase temperature of reduced slag and provide better uniformity of charge heating.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 1; 149-153
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Selected Parameters on Reduction of Converter Slag - Studies with CFD Method
Autorzy:
Kolczyk, E.
Miczkowski, Z.
Czernecki, J.
Powiązania:
https://bibliotekanauki.pl/articles/354046.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
numerical modelling
reduction process
converter slag
Cu-Pb-Fe alloys
Opis:
In this study influence of selected parameters on the process of reduction of converter slag from refining of Cu-Pb-Fe alloy was numerically examined. The process of the slag reduction is carried out in Q 80 converters of Hoboken type for copper removal. Converter slags show high concentration of lead therefore they can be seen as an important component for further processing in rotary-rocking furnaces together with other lead-bearing materials. Three-dimensional simulation was performed using the IPSA (Inter Phase Slip Algorithm) module of two-phase flow from PHOENICS package. Numerical simulations have forecasted influence of changes in the slag chemical composition and the process time on the process course.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 4; 2165-2170
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental investigation of N2O formation in selective non-catalytic NOx reduction processes performed in stoker boiler
Autorzy:
Krawczyk, P.
Powiązania:
https://bibliotekanauki.pl/articles/779234.pdf
Data publikacji:
2016
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
selective non-catalytic reduction process
nitrous oxide emissions
stocker boiler
Opis:
Stoker fired boiler plants are common throughout Eastern Europe. Increasingly strict emission standards will require application of secondary NOx  abatement systems on such boilers. Yet operation of such systems, in addition to reducing NOx  emissions, may also lead to emission of undesirable substances, for example N2O. This paper presents results of experimental tests concerning N2O formation in the selective non-catalytic NOx  emission reduction process (SNCR) in a stoker boiler (WR 25 type). Obtained results lead to an unambiguous conclusion that there is a dependency between the NOx  and N2O concentrations in the exhaust gas when SNCR process is carried out in a coal-fired stoker boiler. Fulfilling new emission standards in the analysed equipment will require 40–50% reduction of NOx  concentration. It should be expected that in such a case the N2O emission will be approximately 55–60 mg/m3, with the NOx  to N2O conversion factor of about 40%.
Źródło:
Polish Journal of Chemical Technology; 2016, 18, 4; 104-109
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mössbauer spectroscopy of reduced forms of a Fe-tetraphenylporphyrine complex
Autorzy:
Kaczmarzyk, T.
Rutkowska, I.
Dziliński, K.
Powiązania:
https://bibliotekanauki.pl/articles/148211.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
DFT calculations
electronic structure
iron-(tetraphenyl)porphyrin
Mössbauer spectroscopy
reduction process
Opis:
Molecular and electronic structure changes during successive reduction of a Fe-tetraphenylporphyrin chloride [Fe(III)(TPP):Cl] complex are reported on the basis of Mössbauer spectroscopy and DFT calculations. It is established that the attachment of additional electrons to a neutral Fe(III)(TPP):Cl molecule leads to signifi cant shortening of Fe-N distances at the fi rst stage of the reduction Fe(III)(TPP):Cl →Fe(II)(TPP) and lengthening of these bonds at the second stage Fe(II)(TPP)→Fe(I)(TPP). Changes of other bond lengths of the porphyrin ring also appear but in less degree. Interaction of Fe(II) and Fe(I)(TPP) with tetrahydrofuran (THF) solvent is considered. Electron configuration of Fe(II)(TPP) corresponds to intermediate-spin (S = 1) state and in the case of Fe(I)(TPP) low-spin state (S = ½) is observed. Electron density distribution in Fe(II)- and Fe(I)(TPP) complexes, in association with Mössbauer data, is analyzed. Good correlation between experimental and theoretical results was obtained.
Źródło:
Nukleonika; 2015, 60, 1; 51-55
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recovery Of Nickel From Spent Nickel-Cadmium Batteries Using A Direct Reduction Process
Odzysk niklu z zużytych baterii niklowo-kadmowych za pomocą bezpośredniej redukcji
Autorzy:
Shin, D. J.
Joo, S.-H.
Wang, J.-P.
Shin, S. M.
Powiązania:
https://bibliotekanauki.pl/articles/355948.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
spent nickel-cadmium batteries
direct reduction
recycling
heat treatment
zużyte baterie niklowo-kadmowe
redukcja bezpośrednia
recykling
obróbka cieplna
Opis:
Most nickel is produced as Ferro-Nickel through a smelting process from Ni-bearing ore. However, these days, there have been some problems in nickel production due to exhaustion and the low-grade of Ni-bearing ore. Moreover, the smelting process results in a large amount of wastewater, slag and environmental risk. Therefore, in this research, spent Ni-Cd batteries were used as a base material instead of Ni-bearing ore for the recovery of Fe-Ni alloy through a direct reduction process. Spent Ni-Cd batteries contain 24wt% Ni, 18.5wt% Cd, 12.1% C and 27.5wt% polymers such as KOH. For pre-treatment, Cd was vaporized at 1024K. In order to evaluate the reduction conditions of nickel oxide and iron oxide, pre-treated spent Ni-Cd batteries were experimented on under various temperatures, gas-atmospheres and crucible materials. By a series of process, alloys containing 75 wt% Ni and 20 wt% Fe were produced. From the results, the reduction mechanism of nickel oxide and iron oxide were investigated.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1365-1370
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł

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