Sharif Digital Repository

An effective corrosion inhibitor for steel is Hexamine (HMTA). There have been few studies on its corrosion-inhibiting characteristics, particularly in NaCl solution. The electrochemical characteristics of HMTA performance in NaCl 3.5 wt% solution were examined during this study. Additionally, the properties of the HMTA film on the steel surface was investigated. When tested in NaCl solution, electrochemical results revealed that HMTA is a very efficient corrosion inhibitor for mild steel, with an efficacy of 92% at a concentration of 0.08 M. HMTA exhibited mixed type activity in terms of inhibition, according to the findings. Due to the physical adsorption of HMTA compound, as shown by the... 

Abstract: Intelligent pH-sensitive nanocontainers were successfully constructed employing the Layer by Layer (LbL) approach. FESEM, HRTEM, EDS, elemental mapping, zeta-potential, FTIR, TGA, SIMS, UV–Vis, and Tafel polarization examinations were subsequently performed on the nanocontainers. Following the LbL procedure, imaging evaluation using FESEM and HRTEM revealed a 42 percent increase in the diameter of SiO2 nanoparticles with a halo view. The effective layer implantation was confirmed by EDS, elemental mapping, and zeta potential recording. Electrostatic interactions between Hexamine (HMTA) compounds and distinct layers were discovered using FTIR. Nanocontainers were found to contain... 

Recent years have seen a significant increase in interest in smart anticorrosion coatings, which can detect corrosive situations and autonomously discharge corrosion inhibitors. The mild steel surface was coated with pH-sensitive nanocontainers that had been manufactured and doped into an epoxy coating. Elemental mapping, thermogravimetric analysis/differential scanning calorimetry, and electrochemical impedance spectroscopy (EIS) methods were used to examine dispersion homogeneity, thermal durability, and corrosion tolerance. The findings indicated that nanocontainers dispersed uniformly in epoxy and that doping nanocontainers had no effect on the epoxy properties. When immersed in NaCl... 

Tolyltriazole (TTA) is a well-defined corrosion inhibitor for copper and copper alloys. However, there is little literature about its corrosion inhibition performance for mild steels in corrosive environments. This paper studied the electrochemical behavior of TTA in 0.5 M HCl solutions. Also, the morphology and nature of TTA layers on the steel surface were investigated. Electrochemical results showed that TTA is an excellent corrosion inhibitor for mild steel in acidic media with an efficiency of 91% for 0.07 M concentration. The results also indicated that TTA is a mixed-type inhibitor. XRD analysis revealed that the inhibition mechanism of TTA is based on the formation of an organic film... 

Smart multilayered pH-sensitive nanocapsules were successfully fabricated using a Layer by Layer (LbL) process. The obtained products were characterized using FESEM, TEM, EDS and elemental mapping, zeta-potential, FTIR, TGA, SIMS and the Tafel polarization techniques. A 55% enhancement in ZrO2 particle size was detected in FESEM and TEM images with a corona view after the LbL process. EDS and elemental mapping analysis and measurements of zeta potential indicated the well-defined layered deposition. FTIR showed the electrostatic bonding between tolyltriazole (TTA) molecules and different overlapping layers. The thermal analysis and SIMS confirmed that 2.7% TTA loaded in nanocapsules. Tafel... 

In this work the titanium dioxide powder was prepared by the optimized and simple Sol-Gel method and then characterized. The gelling pH was set to values of 3 (TiO2-A), 7 (TiO2-N) and 9 (TiO2-B) to observe the effect on the properties of the material. In these three cases nanoparticulated materials were obtained with particle sizes between 10nm and 20nm. The larger surface areas were obtained at pH 3, which is several times larger than the others. Furthermore, with the gelling condition pH 3, it was possible to synthesize pure anatase phase titania. Some preliminary results on the test of the photocatalytic activity of the synthesized materials in the reduction of nitric oxide are presented.... 

The prepared colloidal silica via ion exchange was modified by adding Mg+2 ions in the surface growth process of colloidal silica. The particle size of the modified colloidal silica was decreased by increasing the seed concentration, whereas that of colloidal silica was slightly increased as the seeds concentration exceed 15 wt%. But the trend of changes in surface area was completely reversed. Magnesium ions on surface of the modified colloidal silica were identified by the measurement of energy-dispersive X-ray spectrometry (EDS). After modifying with Mg+2 ions, the iso-electric point (IEP) of colloidal silica in pH ∼ 2 without modification, disappears over the whole pH range. © 2008... 

A series of Cr-substituted Fe-Ti compounds were prepared by the co-precipitation method and were systematically investigated as catalysts for the selective catalytic reduction (SCR) of NO by NH 3. A variety of analytical techniques revealed that the Cr substitution amount affects the N 2 selectivity, SCR activity, redox behavior of NH 3/NO x, adsorption ability, and structure of catalysts in terms of surface properties, porosity, mobility of lattice oxygen, oxidative ability of Cr species, ratio of Bronsted acid sites and Lewis acid sites, NO x adsorption capacity, and structural disorder and distortion. In a series of Fe aCr 1-aTiO x (a = 1, 0.75, 0.5, 0.2, 0) catalysts, Fe 0.5Cr 0.5TiO x... 

Among major components of LiBr-H 2O absorption chillers is the absorber, which has a direct effect on the chillier size and whose characteristics have significant effects on the overall efficiency of absorption machines. In this article, heat and mass transfer process in absorption of refrigerant vapor into a lithium bromide solution of water-cooled incline plate absorber in the Reynolds number range of 5