Sharif Digital Repository

The authors regret to inform that there are inaccuracies in the email address and the affiliation of the third author (F. Madani Sani). The correct email address is: fazlollah.madani.sani@gmail.com. The correct affiliation is: ‘Department of Materials Science & Engineering, Sharif University of Technology, P.O. Box: 11365-9466, Azadi Ave., Tehran, Iran’. Author would like to apologize for the inconvenience caused. © 2017 Elsevier Ltd  

One of the main concerns in cladding Inconel 625 superalloy on desired substrates is deterioration of corrosion resistance due to cladding process. The present study aims to compare the effect of fusion cladding and explosive cladding procedures on corrosion behavior of Inconel 625 cladding on plain carbon steel as substrate. Also, an attempt has been made to investigate the role of load ratio and numbers of fusion layers in corrosion behavior of explosive and fusion cladding Inconel 625 respectively. In all cases, the cyclic polarization as an electrochemical method has been applied to assess the corrosion behavior. According to the obtained results, both cladding methods aggravate the... 

For the first time, the simultaneous effects of sulfate reducing bacteria (SRB), soil type and moisture content on corrosion behavior of a pipeline steel were investigated. Corrosion weight loss measurements were performed in abiotic control and SRB-active conditions, at three different moisture contents, and in two types of soils. Results showed that the presence of SRB in the soils, although increased the corrosion rate and aggravated pitting corrosion at low moisture contents, had a protective effect at high moisture contents. The corrosion rates showed a maximum at the saturation moisture content (SMC) of the soils. Soil physicochemical analyses showed that the corrosion rate and soil... 

In this paper, we investigate the problem of designing compact-support interpolation kernels for a given class of signals. By using calculus of variations, we simplify the optimization problem from an nonlinear infinite dimensional problem to a linear finite dimensional case, and then find the optimum compact-support function that best approximates a given filter in the least square sense (ℓ 2 norm). The benefit of compact-support interpolants is the low computational complexity in the interpolation process while the optimum compact-support interpolant guarantees the highest achievable signal-to-noise ratio (SNR). Our simulation results confirm the superior performance of the proposed kernel... 

Despite the great potential of carbon nanotubes (CNTs) in various areas of biomedicine, concerns regarding their carcinogenicity, inefficient dispersion in aqueous solutions and biological activity in vivo still remain. One important and feasible route to overcome these barriers is modification of CNTs with polymers, which are widely studied and play a vital role in biological and biomedical fields, especially in drug delivery. This comprehensive review focuses on the achievements of our and other groups in currently used methods to functionalize the surface of CNTs with polymers to produce anticancer drug delivery systems. We have intensively studied covalent and noncovalent interactions... 

Caspian Sea - the largest enclosed body of water on earth - is the subject of one of the world's most intractable disputes, involving five coastal states of Azerbaijan, Iran, Kazakhstan, Russia, and Turkmenistan. The conflict over the legal status of this multinational water body emerged after the collapse of the Soviet Union in 1991. Since then the parties have been negotiating without reaching an agreement on the ownerships of waters, and the oil and natural gas beneath them. As long as there is no new agreement on how to share the Caspian Sea among the five states, the two old Iran-USSR treaties may continue to govern the Caspian Sea. Based on these treaties, each state's territorial... 

The purpose of this paper is to estimate the stiffness and strength of damaged rectangular reinforced concrete shear walls after an earthquake using surface crack patterns. Assessing the damage severity of buildings after an earthquake is an important part of the emergency inspection operation of buildings. Expert inspectors tag buildings into two categories of safe or unsafe that are usually affected by subjective decisions, which may result in catastrophic events reported in previous earthquakes. In this research, an extensive database on the images of damaged rectangular reinforced concrete shear walls (RCSWs) is collected and used to develop predictive equations for updated stiffness and... 

In this article we introduce the cylindrical construction, as an edge-replacement procedure admitting twists on both ends of the hyperedges, generalizing the concepts of lifts and Pultr templates at the same time. We prove a tensor-hom duality for this construction and we show that not only a large number of well-known graph constructions are cylindrical but also the construction and its dual give rise to some new graph constructions, applications and results. To show the applicability of the main duality we introduce generalized Grötzsch, generalized Petersen-like and Coxeter-like graphs and we prove some coloring properties of these graphs  

The effects of the current density on the microstructure and the corrosion property of the coating on AZ31 Mg alloy processed by the plasma electrolytic oxidation (PEO) were investigated. The present coatings were produced in an acid electrolyte containing K2ZrF6 with three different current densities, i.e., 100, 150, and 200 mA/cm2. From the microstructural observations, as the applied current density was increased, the diameter of micro-pores formed by the plasma discharges with high temperature increased. The coatings on AZ31 Mg alloy were mainly composed of MgO, ZrO 2, MgF2, and Mg2Zr5O12 phases. The results of potentiodynamic polarization clearly showed that the PEO-treated AZ31 Mg... 

In this research, Magnesia Spinel refractories were formulated by using sintered magnesia, Tabular and Calcined Alumina and sintered Spinel. The grain size distribution of raw materials was modified, using the Andreessen equation. In order to improve the physical and mechanical properties and corrosion resistance of specimens, none stabilized Zirconia was added to the system. The pressed samples were sintered at 1700°C and the properties were evaluated at room and high temperatures. The formed phases and resultant microstructure were also, analyzed by XRD and SEM. The corrosion test was conducted in two parts. First, the depth of corrosion was measured in two zone, within 0-1mm and 1-2 mm... 

The Karkheh River Basin is one of the Iranian river basins with a high potential for hydropower production. While Iran is actively constructing large dams in the Basin for hydropower production, climate change is putting the future status of hydropower production in the Basin in question. Using MODSIM, sensitivity of the Basin to climate change is investigated by estimating stream flow changes and the resulting impacts on hydropower production for different climate change scenarios. Results indicate considerable reductions in annual and seasonal hydropower production due to the expected dry climatic conditions under the existing operation rules. Findings highlight the necessity for revision... 

In this paper, the effect of dolomite type and Al2O3 content on the phase composition in aluminous cements containing MA spinel is investigated. For this reason, the raw and calcined dolomites are used as raw materials along with calcined alumina in the preparation of the cement. Then, different compositions are prepared at 1350 °C using the sintering method and their mineralogical compositions are investigated using the diffractometric technique. Also, their microstructures arre evaluated. The results indicate that raw materials used have great effect on the type and amount of formed phases in cement composition. Independently of the dolomite type used, a mixed phase product consisting of... 

In this study, SnO 2-based varistors were prepared from mechanically activated nanocrystalline powders. Nanocrystalline powders were derived by subjecting the initial powders to intensive high-energy activation with different times and ball to powder ratio. The effect of activation parameters on the powder properties and sintering temperature, as well as microstructural, micro-electrical and macro-electrical properties of the final specimens was evaluated. Varistors derived from high-energy mechanical activation exhibit a higher density (98.3% relative density) and more refined microstructure upon sintering at 1,300 °C in comparison varistors prepared from conventional powders. Breakdown...