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Fine-grained SnO2 varistors prepared by microwave sintering for ultra-high voltage applications
, Article Materials Letters ; Volume 230 , 2018 , Pages 9-11 ; 0167577X (ISSN) ; Mahmoudi, P ; Abdollahi, M ; Ebadzadeh, T ; Sharif University of Technology
Elsevier B.V
2018
Abstract
In this research, fine-grained SnO2-based varistors with a simple microstructure and the mean grain size of 0.8 µm were obtained by the microwave sintering method. The breakdown electric field measured for these varistors was 12 kV/cm that is 3 times higher than the conventional-sintered varistors. The high nonlinear coefficient (60) and low leakage current density (9 µA/cm2) were achieved in fine-grained SnO2 varistors. The fine-grained SnO2 varistors appropriately clamped pulse current surges and the calculated value of the clamping voltage ratio of these varistors was 2. The excellent electrical properties and protective effect of fine-grained SnO2 varistors showed that these varistors...
Study of hole-transporter-free perovskite solar cells based on fully printable components
, Article Micromachines ; Volume 10, Issue 4 , 2019 ; 2072666X (ISSN) ; Raptis, D ; Mohammadi, M. R ; Lianos, P ; Sharif University of Technology
MDPI AG
2019
Abstract
Hole-transporter-free perovskite solar cells carrying a carbon back contact electrode provide the possibility of making full printable low cost and stable devices, even though their efficiency is substantially lower than those made in the standard configuration. The present work searched for simple and easy routes for constructing such devices, demonstrating that organic components do enhance device efficiency but only to a level that is not worth the trouble nor the cost. Devices based on a triple mesoporous layer of titania/zirconia/carbon with perovskite infiltration gave an efficiency of 10.7%. After 180 days of storing under ambient conditions, a small loss of efficiency has been...
Insight into the corrosion inhibition of Biebersteinia multifida root extract for carbon steel in acidic medium
, Article Science of the Total Environment ; Volume 836 , 2022 ; 00489697 (ISSN) ; Soltani, N ; Tavakkoli, N ; Nejatian, A ; Ebrahimian, J ; Mahdi, M. A ; Salavati Niasari, M ; Sharif University of Technology
Elsevier B.V
2022
Abstract
In this project, the protective effect of Biebersteinia multifida root extract (BMRE) against corrosion of 1018 low carbon steel (1018LCS) in HCl solutions was appraised by assessing weight loss, electrochemical impedance spectroscopy (EIS), and polarization at 25 °C. The maximum inhibitory efficacy for the concentration of 1 g/l of the BMRE was 92.8% at 25 °C after 2 h and increased to 95.3% after 24 h of immersion. Polarization experiments have shown that the extract in acidic solutions can act as a mixed corrosion inhibitor. The corrosion inhibitory efficacy of BMRE decreased with increasing temperature, and at all temperature settings studied, the adsorption of BMRE molecules on 1018 LCS...