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Xu B.,Nanjing University of Technology | Liu Y.,Nanjing University of Technology | Yin X.,Nanjing University of Technology | Yang W.,Nanjing University of Technology | Chen Y.,Jiangsu Polytechnic University
Corrosion Science | Year: 2013

The corrosion inhibition effect of 3-pyridinecarboxaldehyde thiosemicarbazone (3-PCT) on mild steel was studied in 1. M HCl solution by means of weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. The surface morphology of mild steel was examined with scanning electron microscopy (SEM) and the mechanism of inhibition was determined by the potential of zero charge (PZC) measurement at the metal-solution interface. Then molecular dynamics simulations were also executed for 3-PCT. The results show that 3-PCT is a good corrosion inhibitor, retarding both cathodic and anodic reactions in hydrochloric acid. The adsorption of 3-PCT on the mild steel surface obeys the Langmuir isotherm, and the thermodynamic parameters (Kads,Ea,δGads0) were also determined and discussed. © 2013 Elsevier Ltd.

Qian J.,Jiangsu Polytechnic University | Qian J.,Nanjing University of Technology | Shi H.,Nanjing University of Technology | Yun Z.,Nanjing University of Technology
Bioresource Technology | Year: 2010

In the present work the preparation of biodiesel from Jatropha curcas L. oil produced by two-phase solvent extraction (TSE) was studied. The experimental results of TSE process showed that the optimal extraction conditions were 30 g samples, 240 mL of extraction solvent mixture and methanol/n-hexane volume ratio 60:40, extraction temperature 35 °C, extraction time 30 min. Further, the effect of methanol recycling on the TSE process was also investigated. After TSE process, the investigations were carried out on transesterification of methanol with oil-n-hexane solution coming from TSE process in the presence of sodium hydroxide as the catalyst. The conversion could achieve 98% with 3:1 n-hexane/oil weight ratio, 60 °C reaction temperature, 7:1 methanol/oil mole ratio, 1.1% alkali catalyst concentration and 120 min reaction time. The properties of fatty acid methyl ester (FAME) product prepared from Jatropha curcas L. oil produced by two-phase solvent extraction met the ASTM specifications for biodiesel. Crown © 2010 Published by Elsevier Ltd. All rights reserved.

Qiu J.H.,Jiangsu Polytechnic University
Solid State Communications | Year: 2010

Based on a phenomenological thermodynamical theory, the effect of the domain wall on the dielectric properties of the polydomain BaTiO3/SrTiO3 superlattices with 180° electric domains in the BaTiO3 layer is investigated. Theoretical analysis indicates that complete polarization suppression and the largest dielectric response take place at approximately 72% and 53% of the critical volume fraction of the SrTiO3 layer for the domain wall energy parameter A=3×107 and 5×107, respectively. The dielectric properties largely depend on both the volume fraction of the SrTiO3 layer and the domain wall energy parameter. Moreover, the gigantic dielectric response which occurs in single-domain BaTiO3/SrTiO3 superlattices cannot appear due to the 180° polydomain state in the BaTiO3 layer, which is in agreement with the previous prediction. The high domain wall energy parameter results in the stabilization of the paraelectric state in the BaTiO3 layer, however, the enhancement of the domain wall energy parameter within a certain scale increases the dielectric properties greatly. © 2010.

Zhang Y.,Jiangsu Polytechnic University
Journal of Computational and Theoretical Nanoscience | Year: 2010

Boundary lubrication effect is investigated in isothermal line contact elastohydrodynamic lubrication (EHL) by using the inlet zone analysis method and taking the nanometer-scale thin film lubrication analytical approach proposed by the author.1 Calculation of the load carried by the EHL contact is made for the film thickness in the Hertzian contact zone ranging from 2 nm to 20 nm when the dimensionless material parameter G is 4500, the dimensionless rolling speed U is 1.0E-12, and the compound curvature radius of the contact surfaces R is 10 mm. Calculation is also made for different contact-lubricant interaction strengths represented by the critical thickness parameter hcr of boundary film. Results show that when the film thickness in the Hertzian contact zone is on the 1 nm scale (or lower), the load carried by the EHL contact can be considerably increased when the boundary lubrication in the EHL contact is considered; Otherwise, the change of the carried load by the EHL contact because of boundary lubrication consideration is negligible, and conventional EHL model can cover the whole EHL contact. Results also show that the compressibility of the lubricant due to the contact-lubricant interaction considerably reduces the load-carrying capacity of the EHL contact when the Hertzian contact zone is in boundary lubrication. Copyright © 2010 American Scientific Publishers. All rights reserved.

Wang M.,Jiangsu Polytechnic University
Computers and Mathematics with Applications | Year: 2010

In this paper, we obtain some new inequalities by means of the mean inequalities of random variables, which include generalizations of the Greub-Rheinboldt inequality. © 2010 Elsevier Ltd. All rights reserved.

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