Emissions of greenhouse gases due to human activities have been well documented as well as the effects on global warming resulting from it. Efforts to reduce greenhouse gases at the source are crucial to curb climate change, but due to insignificant economic incentives to reduce usage of fossil fuels, not a lot of progress has been made by this route. This necessitates additional measures to reduce the occurrence of greenhouse gases in the atmosphere. Here we used theoretical methods to study the solubility of carbon dioxide in ionic liquids (ILs) since sequestration of CO2 in ILs has been proposed as a possible technology for reducing the emissions of CO2 to the atmosphere. Ionic liquids form a class of solvents with melting temperatures below 100 °C and, due to very low vapor pressures, which are not volatile. We have performed molecular dynamics (MD) simulations of 1-ethyl-3-methylimidazolium (C2mim) bis(trifluoromethylsulfonyl)imide (Tf2N) and its mixtures with carbon dioxide in order to investigate the CO2 concentration effect on the CO2-cation and CO2-anion interactions. A systematic investigation of CO2 concentration effects on resulting equilibrium liquid structure, and the local environment of the ions is provided. The Quantum Theory of Atoms in Molecules (QTAIM) was used to determine the interaction energy for CO2-cation and CO2-anion complexes from uncorrelated structures derived from MD simulations. A spatial distribution function analysis demonstrates the specific interactions between CO2 and the ionic liquid. Our findings indicate that the total volume of the system increases with the CO2 concentration, with a molar volume of CO2 of about 0.038 L/mol, corresponding to liquid CO2 under a pressure of 100 bar. In other words, the IL effectively pressurizes the CO2 inside its matrix. The thermodynamics of CO2 solvation in C2 min-Tf2N were computed using free energy techniques, and the solubility of CO2 is found to be higher in this IL (-3.7 ± 1 kcal/mol) than in water (+0.2 kJ/mol), predominantly due to anion-CO2 interactions.

In this work was investigated the microstructural evolution process of the duplex stainless steel SAF 2205 as-cast after solution annealing treatment. The aim was to detect the effects on the material microstructure by the cooling rate variation. The studied material were submitted to solution anneal at 1100 °C for 240 min, followed by cooling in water, air and furnace. The results evaluation was based on micrographic analysis, energy dispersive spectrometry measurements (EDS), X-ray diffraction and hardness tests. The ferrite volume fraction obtained in the microstructure increased with the cooling rate, because it causes diffusion inhibition of the steel constituent elements, promoting retention of the ferrite. The volume fraction of austenite phase increased with a lower cooling rate. The cooling rate is an important factor in defining the steel microstructure, particularly about intermetallic phases precipitation, which occurred by the slow cooling rate. Additionally, it was observed the precipitation of sigma phase.

Titanium and stainless steel are examples of biomaterials widely used in dental and orthopedic implants owing to their properties of good corrosion resistance and excellent biocompatibility. This paper reports on a study of the biomimetic method applied to titanium (cp-Ti) and 316L stainless steel. The method consists in immersing the metal substrate in a synthetic solution of SBF (simulated body fluid) whose composition, pH and temperature resemble those of human blood plasma. The coating on the two metals was effective for obtaining hydroxyapatite, which was confirmed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR).

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Commercially pure titanium and its alloys have been widely applied as implant materials with excellent long-term results and present benefits compared to other metal biomaterials because of the good mechanical strength and modulus of elasticity with values close to those of the bone. Titanium implants coated with hydroxyapatite give the metal a bioactive surface, which induces a direct connection between the implant and the bone tissue. As a consequence, the time for osseointegration, and hence the total treatment time, may be reduced. This paper aimed at studying the bactericidal effect of silver nitrate at 10 ppm and 100 ppm, incorporated in the layer on the surface of commercial titanium. The results showed efficiency in both osseointegration and bactericidal effect, confirmed by scanning electron microscopy, X-ray diffraction and corrosion tests. The bacterial culture tests, by means of the halo inhibition tests, indicate that the doping with AgNO3in concentrations 10 and 100 ppm did not present significant variation.