A novel efficient numerical method to simulate electrochemical process for a lithium ion battery

The simulation plays an important role in understanding of electrochemical behavior and internal process of lithium ion batteries. The existing finite difference method (FDM) to conduct the simulation of electrochemical process is time-consuming and computationally expensive. In this paper, a novel numerical method is proposed to accelerate the solution of the electrochemical model for a lithium ion battery. It is implemented in three steps. In the first step, physical analogy of electrochemical process to an electric circuit is used to solve charge conservation equations. In the second and third step, control volume method is used to solve species conservation equations. The simulation results show that the proposed method is much faster than the FDM by 2.2 times while maintain high accuracy which is verified by simulation and experimental data as well.     

Redox control of a ring-opening polymerization catalyst

The activity of an yttrium alkoxide complex supported by a ferrocene-based ligand was controlled using redox reagents during the ring-opening polymerization of L-lactide. The oxidized complex was characterized by X-ray crystallography and (1)H NMR, XANES, and M?ssbauer spectroscopy. Switching in situ between the oxidized and reduced yttrium complexes resulted in a change in the rate of polymerization of L-lactide. Synthesized polymers were analyzed by gel permeation chromatography. Polymerization of trimethylene carbonate was also performed with the reduced and oxidized forms of an indium alkoxide complex. The indium system showed the opposite behavior to that of yttrium, revealing a metal-based dependency on the rate of polymerization.     

Investigation of the effect of cobalt on the Ni–Al2O3 catalyst prepared by the mechanochemical method for CO2 methanation

Research on Chemical Intermediates - Various Ni–Co catalysts supported on alumina were produced by the mechanochemical technique and applied to CO2 Methanation. X-ray diffraction,...     

Sterols from Sargassum oligocystum, a brown algae from the Persian Gulf, and their bioactivity

Sargassum oligocystum (Heterokontophyta) is one of the most abundant algae distributed in the Persian Gulf. In this study, the cytotoxic effects of this algae on brine shrimp larvae were evaluated and the main sterols of the algae identified. Separation and purification of the compounds was carried out using silica gel column chromatography and HPLC to obtain eight pure compounds, 1-8. Structural elucidation of the constituents was based on the data obtained from (1)H-NMR, (13)C-NMR, HSQC, HMBC, DEPT and EI-MS. The compounds separated from S. oligocystum were identified as 22-dehydrocholesterol (1), cholesterol (2), fucosterol (3), 29-hydroperoxystigmasta-5,24(28)-dien-3β-ol (4), 24-hydroperoxy-24-vinylcholesterol (5), a mixture of 24(S)-hydroxy-24-vinylcholesterol (6) and 24(R)-hydroxy-24-vinylcholesterol (7), and ostreasterol (8) based on their spectral data and from comparison with those previously reported in the literature.     

Inherent safety evaluation in process plants— a comparison of methodologies

A global population increase and an improved standard of living are generally expected. To meet these demands, an increased production of chemicals will be necessary while protecting human health and the environment. However, most current methods of chemical production are unsustainable. New designs must result in plants that assure process and operator safety, the sustained health of workers and the community, and the protection of the environment. Traditional safety precautions and process controls minimize risk but cannot guarantee the prevention of accidents followed by serious consequences. Therefore, the general approach to environmental and safety problems must be changed from reactive to proactive. One way is to further develop the concept of inherent safety. In this paper some methods for inherent safety evaluations are reviewed. The aim of the study is to analyze the different tools available for inherent safety evaluation and identify the most important criteria in determining the inherent safety of a process plant. A model is proposed to show the interactions of different factors on the inherent safety level of a process and the model is illustrated by a case study.     

Transient thermal stress analysis for a short thick hollow FGM cylinder with nonlinear temperature-dependent material properties

Journal of Thermal Analysis and Calorimetry - In this study, nonlinear transient thermo-elastic analysis for a thick hollow 1D-FGM (functionally graded material) axisymmetric cylinder with finite...