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Background: Evans’s drop is a classic corrosion experiment that is nearly 100 years old, and it is analogous to other corrosion systems promoted by O2 gradients. The availability of more robust finite element software packages opens the possibility to reach a deeper understanding of these kind of corrosion systems. Methodology: In order to solve the problem, the model includes the governing mass transport diffusion and migration equation and the material balance in a nonsteady state by the finite element method. This is performed using COMSOL Multiphysics to predict the tertiary current and potential distribution considering the geometry, reaction kinetics, and mass transport for each ionic species. Significant Findings: A simulation of the tertiary current and potential distribution of the Evans’s drop corrosion experiment on an iron surface is presented. An oxygen concentration difference of 0.18 mol m−3 between the center and the drop periphery sets up a potential difference of 60 mV which acts as a corrosion driving force. Reaction kinetics are described by Tafel equations. Results include the evolution of concentration profiles for OH−, Fe2+, Fe3+, Fe(OH)2, and Fe(OH)3.

In this work, tetrahydroxyquinone (THQ) was used for the first time to coat iron oxide nanoparticles (IONPs) and to carry out in vitro experiments in magnetic hyperthermia. Synthesis by co-precipitation resulted in spherical IONPs with a core diameter of 13 ± 3 nm and covered by a 0.5 nm thick coat of THQ, which provided them with a reasonably good zeta potential of ζ = −28 ± 2 mV at pH = 7.3, and thus colloidal stability. The magnetic properties of the THQ-coated IONPs are promising: the low coercive field of Hc = 7 Oe, the high magnetic saturation of Ms = 70.5 emu/g and the low blocking temperature of Tb = 273 K indicate superparamagnetic characteristics at room temperature. Additionally, a high specific absorption rate SAR = 135 W/g (at 300 Oe and 530 kHz) was determined. Cell biological experiments using the human cell line HT-29 evidenced negligible cytotoxicity up to 2 mg/mL. Magnetic hyperthermia (MHT) assays demonstrated fast and reliable heating and reduced the metabolic activity of the cells to 42% upon reaching 42 °C within 15 min. The production of ROS by THQ-coated IONPs could not be detected, which may indicate a reduction in the undesired side effects caused by oxidative stress. Considering these good physicochemical and cell biological properties, this ferrofluid is a promising candidate for the initiation of in vivo experiments for cancer treatment by MHT in murine models.

Silver nanowires were synthesized by polyol method to be used on the surface modification of silver cathodes in alkaline zinc-silver oxide batteries with the aim of increasing the electroactive area and improving its energy storage capacity. The morphological and structural characterization was performed by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV absorption. The modified electrodes were evaluated by using cyclic voltammetry and discharge curves of batteries. The energy storage capacity increased about 53.73% when the modified electrodes with silver nanowires were used.

In this paper, the method of lines for predicting current responses as a function of potential for systems with single or multiple electron transfers, coupled with homogeneous chemical reactions and its implementation in an open-source code written in the freeware programming language Python is presented. The application of this method allows simulating cyclic voltammograms for any proposed mechanism and to obtain concentration profiles for each of the species participating in the reactions. Some of benefits for applying this strategy includes: a) the method does not require dimensionless variables, b) it is possible to carry out a direct simulation of current responses and concentration profiles for all participating species c) Its use is not limited by second party author copyright license and d) the method is easy to implement as an application.