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... 

Feed-in tariff (FiT) is one of the most efficient ways that many governments throughout the world use to stimulate investment in renewable energies (REs) technology. For governments, financial management of the policy could be challenging as it needs a considerable amount of budget to support RE producers during the long remuneration period. In this paper, it has been illuminated that the early growth of REs capacity could be a temporary boost. And the socio-economic structure of the system will backlash the policy if some social mechanisms are not considered. Social tolerance for paying REs tax and potential investors’ trust emanated from budget-related mechanisms -which have rarely been... 

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 paper, we consider multiple multicast sessions with intra-session network coding where rates over all links are integer multiples of a basic rate. Although having quantized rates over communication links is quite common, conventional minimum cost network coding problem cannot generally result in quantized solutions. In this research, the problem of finding minimum cost transmission for multiple multicast sessions with network coding is addressed. It is assumed that the rate of coded packet injection at every link of each session takes quantized values. First, this problem is formulated as a mixed integer linear programming problem, and then it is proved that this problem is strongly... 

This work describes a very simple, novel and selective spectrophotmetric method for simultaneous determination of sulfamethoxazole and trimethoprim in pharmaceutical preparation and synthetics samples using direct orthogonal signal correction-partial least squares (DOSC-PLS). The all factors affecting on the sensitivity were optimized and the linear dynamic range for determining of these drugs was found. The PLS modeling was used for the multivariate calibration of the spectrophotometric data and DOSC was used for preprocessing of data matrices and the prediction results of model. The experimental calibration matrix was designed by measuring the absorbance over the range 200-400 nm for 32... 

Although hematite (i.e., α-Fe2O3) has been widely investigated in photoelectrochemical water oxidation studies due to its high theoretical photocurrent density, it still suffers from serious surface charge recombination and low photoelectrochemical stability. Here we report an in situ electrochemical method to form a uniform and ultrathin (i.e., 3-5 nm) passivation layer all over the pores of an optimized ∼3.2% Ti-doped α-Fe2O3 photoanode. We unveil the amorphous and defective nature of the in situ derived layer assigned to a high concentration of oxygen vacancies and intercalated potassium atoms there, i.e., the formation of Ti/K co-doped defective α-Fe2O3−x. Owing to the efficient... 

Ramsar, in the north of Iran by the Caspian Sea, has been known for the highest natural radiation background on Earth due to the local geology and hydrogeology. The residents and visitors use the hot springs that distribute the natural radionuclides especially 226Ra and its decay products in the areas. Many studies have been undertaken to measure the absorbed dose rate in Ramsar's air, however, no survey has been done to assess public internal exposure from ingestion of natural radionuclides, such as, a broad survey for 226Ra was conducted in foodstuffs and drinking water. This study presents the results of public annual activity intake (Bq) and effective dose (μSv) from ingestion of 226Ra... 

Among High Level Natural Radiation Areas (HLNRAs) all over the world, the northern coastal city of Ramsar has been considered enormously important. Many studies have measured environmental radioactivity in Ramsar, however, no survey has been undertaken to measure concentrations in the diets of residents. This study determined the 226Ra activity concentration in the daily diet of people of Ramsar. The samples were chosen from both normal and high level natural radiation areas and based on the daily consumption patterns of residents. About 150 different samples, which all are local and have the highest consumption, were collected during the four seasons. In these samples, after washing and... 

Background: Ramsar, a city of Iran located on the coast of the Caspian Sea, has been considered to be enormously important due to its high natural radioactivity levels. People living in High Level Natural Radiation Areas (HLNRAs) have been exposed by several sources, one of which could be foodstuff. However, many studies have been carried out to measure the environmental radioactivity in Ramsar, but no survey has been conducted in all stapled consumed foods yet. This study was dedicated to determine 226Ra activity concentration in the daily diets of Ramsar residents as a probable exposure. Methods: Approximately 70 different market samples were collected during the four seasons based on the...