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Wyświetlanie 1-4 z 4
Tytuł:
Corrosion inhibition potential of Terminalia avicennioides extract on mild steel in 1.0 M HCl: kinetics, thermodynamics and synergestic studies
Autorzy:
Ijuo, G. A.
Surma, N.
Oloruntoba, S. O.
Powiązania:
https://bibliotekanauki.pl/articles/1177459.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Terminalia avicennioides
inhibition efficiency
physisorption
synergestic effect
Opis:
The corrosion inhibition effect of Terminalia avicennioides (TA) stem extract in 1.0 M HCl solution was investigated using weight loss and electrochemical method. The operation variables considered include temperature (303-333 K) and concentration of the inhibitor (0.2 - 1.0 g/L). Inhibition efficiency increased from 21.88% to 88.71% with concentration but decreased with rise in temperature which is suggestive of physisorption. This was supported by the values of activation energies (Ea) obtained ranging from 22.67 KJ mol−1 to 60.67 KJ mol−1 which was lower than 80 KJ mol−1. The values of Gibb’s free energy of adsorption (∆Gads) indicated that the adsorption of the inhibitor on mild steel surface was a spontaneous process. The Kinetic treatment of the data followed a pseudo-first order reaction while the positive values obtained for enthalpy and entropy of activation is reflective of endothermic reaction nature and associative activation complex respectively. The adsorption mechanism followed the Langmuir adsorption isotherm model. Electrochemical analysis showed that the inhibitor functioned as a mixed type inhibitor. The inhibition efficiency of the inhibitor was found to be enhanced by the presence of KI. Therefore the extract functioned as good corrosion inhibitor for mild steel in 1.0 M HCl.
Źródło:
World Scientific News; 2018, 102; 1-16
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization and optimization study of Ficus exasperata extract as corrosion inhibitor for mild steel in seawater
Autorzy:
Oyewole, O.
Aondoakaa, E.
Abayomi, T. S.
Ogundipe, S. J.
Oshin, T. A.
Powiązania:
https://bibliotekanauki.pl/articles/1031411.pdf
Data publikacji:
2021
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Corrosion
Ficus exasperata
inhibition efficiency
optimization
weight loss
Opis:
This study investigated the characterization of Ficus exasperata extract and the optimization of the process variables on inhibition of mild steel in seawater environment. Box Behnken Design was employed to examine the influence of three process variables: Temperature: 25-29 °C; Time: 3 – 6 days; Inhibitor concentration: 1-5 v/v. Phytochemical screening of the extract was done. The physicochemical constituents of the seawater were also determined. The experimental data was statistically determined and Scanning Electron Microscope (SEM) was used to characterize the mild steel. The result of the phytochemical screening of the Ficus exasperata plant extract (FEPE) showed the presence of contain inhibitive constituents: alkaloids, tannins, saponins, flavonoids and glycosides. The highest inhibition efficiency of 86.31% at a temperature of 29 ℃ for 6days at an inhibition concentration of 3v/v was observed from the experimental run. The optimal process levels of time: 5.74 days, temperature: 27.95 ℃ and inhibitor concentration: 2.90v/v, gave 87.52% as its inhibition efficiency. The result of the SEM from the optimal process level validated showed that more passive film was formed which can be attributed to the adsorption of the Ficus exasperata extract. It can be concluded that the Ficus exasperata was a good eco-friendly inhibitor.
Źródło:
World Scientific News; 2021, 151; 78-94
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of Some Inorganic Anions and Organic Compounds as Corrosion Inhibitors of Cu-Zn Alloys in H2SO4 and HNO3 Solutions
Autorzy:
Ahmed, Amal S. I.
Ghanem, Wafaa A.
Hussein, Walaa A.
Gaber, Ghalia A.
Powiązania:
https://bibliotekanauki.pl/articles/351226.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Cu-Zn alloys
oxy-acid solution
inhibition efficiency
inorganic anions
organic compounds
Opis:
Evaluation of inorganic and organic compounds as corrosion inhibitors of Cu-Zn alloys in H2 SO4 and HNO3 solutions was studied using potentiodynamic and impedance spectroscopy along with scanning electron microscope (SEM) and energy dispersive X-Ray analyzer (EDX) investigations. The corrosion inhibition of Cu-Zn alloys was investigated in oxy acid solutions using inorganic potassium permanganate and di-hydrogen phosphate, amino acids as environmentally safe materials, commercial cooling water, and green tea extracts. Both potassium permanganate and di-hydrogen phosphate improve the corrosion resistance of Cu-Zn alloys. Phosphate appears more effective as corrosion inhibitor for Cu-Zn alloys than permanganate. The inhibition efficiency (IE%) of the different amino acids such as valine, leucine and lysine was also calculated. The experimental results have shown that amino acid-like lysine can be used as an efficient corrosion inhibitor for the Cu-Zn alloys in oxy acid solutions. This may be due to the presence of two amino groups adsorbed together. For lysine, inhibition efficiency, IE%, of ~87 and ~59 is for H2SO4 and ~96.3 and 54.9 for HNO3 for alloy I and II respectively are observed. Due to the composition of green water have a great effect on the inhibition action on Cu-Zn alloys which reaching 91.8 and 96.5% for Alloy I and 95.4 and 87.1% for Alloy II in 0.5 M H2 SO4 and HNO3 respectively. Although benzotriazole, in cooling water, is an excellent inhibitor suitable for use in a wide variety of environments, it has toxic properties. So, much of the recent researches have focused on formulating new and more environmentally acceptable preservation solutions. The green tea, as plant extract, will be very environmentally friendly. The EDX confirm the formation of a protective layer on the Cu-Zn alloys containing aluminum in Alloy II. This sequence reflects the beneficial effects of Al in Alloy II. The presence of 2.43% Al in Alloy II improves the corrosion resistance due to the formation of thin, transparent, stable and self-healing Al2 O3 layer. This confirmed the results obtained from the potentiodynamic polarization measurements and EIS methods.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 2; 639-651
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inhibition of poly(ADP-ribose) polymerase activity affects its subcellular localization and DNA strand break rejoining
Autorzy:
Ryabokon, Nadezhda
Cieślar-Pobuda, Artur
Rzeszowska-Wolny, Joanna
Powiązania:
https://bibliotekanauki.pl/articles/1040571.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
DNA strand break rejoining
efficiency of PARP inhibition
PARP foci
poly(ADP-ribose) polymerase (PARP)
PARP inhibitors
Opis:
Poly(ADP-ribose) polymerase (PARP) plays a crucial role in DNA repair. Modulation of its activity by stimulation or inhibition is considered as a potentially important strategy in clinical practice, especially to sensitize tumor cells to chemo- and radiotherapy through inhibition of DNA repair. Here we studied the effect of the three PARP inhibitors, 5-iodo-6-amino-benzopyrone (INH2BP), 1,5-isoquinolinediol (1,5-dihydroxyisoquinolinediol (1,5-IQD) and 8-hydroxy-2-methylquinazolin-4-[3H]one (NU1025), and for two of them the efficiency in slowing the rejoining of DNA strand breaks induced by H2O2 was compared. Inhibition of PARP changed its intranuclear localization markedly; cells exposed to the inhibitor NU1025 showed a significant tendency to accumulate PARP in large foci, whereas in untreated cells its distribution was more uniform. The speed and efficiency of rejoining of H2O2-induced DNA strand breaks were lower in cells incubated with a PARP inhibitor, and the kinetics of rejoining were modulated in a different manner by each inhibitor. At a concentration of 100 µM the efficiency of the inhibitors could be ranked in the order NU1025 > IQD > INH2BP. The two first compounds were able to decrease the overall PARP activity below the level detected in control cells, while INH2BP showed up to 40% PARP activity after exposure to H2O2.
Źródło:
Acta Biochimica Polonica; 2009, 56, 2; 243-248
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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