Sharif Digital Repository

In this study, dissimilar friction stir welding was performed between AA5052 aluminium and AZ31 magnesium alloys using a variety of parameters. The results revealed that the optimal range of welding parameter is between 20 and 38 rpm/mm.min−1 (the ratio of rotation speed to travel speed). The findings of the X-ray diffraction and Micro-hardness tests on the stir zone indicated that when the rotation speed is increased, it leads to the formation of intermetallic compounds such as Al12Mg17 and Al3Mg2. The polarization test was used to assess the corrosion rate in various zones. The corrosion rate in the stir zone is higher than in other zones due to macro-galvanic couple between Al and Mg.... 

Improving testability during the early stages of high-level synthesis has several benefits including reduced test hardware overheads, reduced test costs, reduced design iterations, and significant improved fault coverage. In this paper, we present a novel register allocation method, which is based on weighted graph coloring algorithm, targeting testability improvement for digital circuits. In our register allocation method, several high-level testability parameters including sequential depth, sequential loop, and controllability/observability are considered. Our experiments show using this register allocation method results in significant improvement in automatic test pattern generation time... 

Improving testability during the early stages of High-Level Synthesis (HLS) has several benefits, including reduced test hardware overhead, reduced test costs, reduced design iteration, and significant improved fault coverage. In this paper, we present a novel register allocation method, which is based on weighted graph coloring algorithm, targeting testability improvement for digital circuits. The topics covered in this paper include an overview of HLS and testability parameters, our testability model and experimental results  

Improving testability during the early stages of High-Level Synthesis (HLS) reduces test hardware overheads, test costs, design iterations, and also improves fault coverage. In this paper, we present a novel register allocation algorithm which is based on weighted graph coloring, targeting testability improvement. © 2003 IEEE  

There has been no isolated word recognition database for the Persian language so far. In this paper we introduce FarsName dataset which contains 20 thousands isolated-word Persian utterances spoken by 226 speakers from all regions of the country each saying an average of 88 Persian names. There is a total of 5235 unique names in this dataset. Various cell phone brands have been used to record this dataset. This indicates the high diversity of the utterances in this dataset. We have been able to achieve 10.34% WER on this set using Kaldi. This is a very good performance considering the recording environment have been normal and potentially noisy. © 2017 IEEE  

Despite extensive studies, hydrogels are unable to meet the mechanical and biological requirements for successful outcomes in cartilage tissue engineering. In the present study, beta cyclodextrin (β-CD)-modified alginate/cartilage extracellular matrix (ECM)-based interpenetrating polymer network (IPN) hydrogel was developed for sustained release of Kartogenin (KGN). Furthermore, the hydrogel was incorporated within a 3D-printed poly (ε-caprolactone) (PCL)/starch microfiber network in order to reinforce the construct for cartilage tissue engineering. All the synthesized compounds were characterized by H1-NMR spectroscopy. The hydrogel/microfiber composite with a microfiber strand size and... 

One of the underlying factors in the conservation and development of urban green spaces is the available water resources use for green areas in each region. The primary purpose of this study is to introduce the integration of a proper simulation method for runoff along with AHP-PROMETHEE decision-making method for water resources management in urban basins. The application of this approach was investigated in the city Buin Zahra of Qazvin Province of Iran. In the first step by using the analytic hierarchy process (AHP), the available water resources in the case study were weighted. In the second step, the water resources of the municipal and residential wells and water collected by... 

One of the underlying factors in the conservation and development of urban green spaces is the available water resources use for green areas in each region. The primary purpose of this study is to introduce the integration of a proper simulation method for runoff along with AHP-PROMETHEE decision-making method for water resources management in urban basins. The application of this approach was investigated in the city Buin Zahra of Qazvin Province of Iran. In the first step by using the analytic hierarchy process (AHP), the available water resources in the case study were weighted. In the second step, the water resources of the municipal and residential wells and water collected by... 

In this paper, for the first time, chaotic behavior of a classical moving-mirror Fabry-Perot cavity is obtained by finding numerical solution of a system of delay differential equations (previously obtained by a phenomenological approach (T. Carmon, M. C. Cross, K. J. Vahala, Phys. Rev. Lett. 98 (2007) 167203)). Fourier transform of the electromagnetic power for different values of pump power is calculated. By increasing the power, a period-doubling route to chaos is observed. Since the quality factor of the cavity has an important role in the chaotic behavior, variation of Lyapunov exponent and threshold power for the onset of chaos versus quality factor are investigated. A near linear... 

Electrocoagulation is an effective, fast, and economic method for treatment of industrial wastewaters. In this study, effects of different parameters including electrolysis time, voltage, and pH on the reduction of chemical oxygen demand (COD), lignin, and color in pulp and paper wastewaters were studied. Iron and aluminum were used as anode and cathode electrodes, respectively. Under the optimal conditions (pH 5, 60 min, 10 V), this treatment method led to 85% removal of COD and 78.5% removal of lignin. Furthermore, clear treated water with complete color removal was generated that suggests the application of electrocoagulation for industrial wastewater treatment, especially in pulp and... 

This study investigated the diesel and COD removal from oily wastewater by electrocoagulation. Experiments were conducted in a 2-l reactor using aluminum and iron electrodes. Effects of different parameters including pH (3–11), time (10–60 min), voltage (4.5–10.5 V), supporting electrolyte (NaCl concentration), electrode material and initial diesel concentration (3500–11,000 mg/L) were studied in order to evaluate the efficiency of electrocoagulation. Furthermore, the consumption of energy and the amount of sludge produced by this method were evaluated. The highest removal efficiency (COD removal of 99.1 ± 0.2 % and diesel removal of 98.8 ± 0.2 %) was observed under the following conditions:... 

3D Network-on-Chips (3D NoCs) have higher scalability, higher throughput, and lower power consumption over 2D NoCs. However, the reliability of data transfer in 3D NoCs is seriously threatened by thermal problems. This is due to poor heat dissipation, inappropriate traffic distribution, and cooling restriction for layers away of the chip heat-sink in 3D NoCs. To solve this problem, this paper proposes an efficient deadlock-free and traffic-And thermal-Aware routing algorithm, called Floating XY-YX. The main idea behind Floating XY-YX routing algorithm is twofold: 1) to use XY and YX routing algorithms in consecutive layers in dessicate form, and 2) to evenly load the traffic, which is... 

Although many Dynamic Thermal Management (DTM) techniques are employed to overcome thermal problems in 3D NoCs, none of them consider temperature information of all nodes of a layer at the same time, so that they cannot reduce the temperature of the network properly.To overcome this problem, this paper proposes an efficient proactive thermal-aware routing algorithm, called Less Entrance to Hot Regions (LETHOR), to keep the NoC temperature lower than a predefined thermal limit. LETHOR routes the network packets based on the temperature information of all nodes in the layers instead of considering only the neighbor nodes in each hop. To this aim, LETHOR introduces a Hot Region in each layer... 

We consider a market in which two competing sellers offer two similar products on a social network. In this market, each agent chooses iteratively between the products based on her neighbors reactions and prices. This introduces two games: one between the agents and one between the sellers. We show that the first game is a full potential game and provide an algorithm to compute its convergence point. We also study various properties of the second game such as its equilibrium points and convergence  

Superhydrophobic surfaces (SHSs) are considered to be a promising technology for achieving skin-friction drag reduction. Development of more efficient techniques for simulating the turbulent boundary layer on SHSs continues to be a subject of interest. In this study, numerical simulations were carried out to capture near-wall behaviours due to the effect of the SHS on wall-bounded flows. To achieve this, high- to intermediate-fidelity turbulence models including Reynolds-averaged Navier-Stokes, detached eddy simulation and large eddy simulation were utilized. With regard to slip conditions, the well-known Navier slip velocity method was used over the SHS. For validating the numerical... 

We introduce hyper-D-width and hyper-T-width as the first stable (see Definition 3) measures of connectivity for hypergraphs. After studying some of their properties and, in particular, proposing an algorithm for computing nearly optimal hyper-T-decomposition when hyper-T-width is constant, we introduce some applications of hyper-D-width and hyper-T-width in solving hard problems such as minimum vertex cover, minimum dominating set, and multicut  

The Three-Dimensional Network on Chip (3D NoC) is an interconnection architecture designed to address the increasing communication demands between processing cores. However, as traffic and power density continues to rise, efficient traffic management and thermal regulation within these chips have become crucial issues. One common problem encountered in mesh-based NoC structures, regardless of the routing approach employed, is traffic congestion in the central region. This paper introduces a novel routing algorithm named an Oblivious Congested Region Avoiding Routing Algorithm (OCRA) to evenly distribute packet flow across the entire network. OCRA addresses the traffic imbalance by statically... 

Precipitation of strontium sulfate (or SrSO4) has already been distinguished as one of the most costly and critical problems which may occur in process industries and oilfield operations. Costs due to scaling and remedial actions that need to be taken afterward are generally high owing to low solubility of SrSO4 in aqueous solutions. Therefore, a thorough understanding of the SrSO4 thermodynamic behavior under various operating conditions is vital to predict or even avoid the overall damage caused by scaling. The primary aim of this work is to develop a model based on Least Squares Support Vector Machine (LSSVM) and Coupled Simulated Annealing (CSA) referred to as CSA-LSSVM to predict... 

The affiliations in the original article contain errors. The correct affiliations are given below. © 2016, Islamic Azad University (IAU)  

In the present study, the performance of three moving bed biofilm reactors (MBBRs) has been evaluated in series with anaerobic/anoxic/oxic (A2O) units for simultaneous removal of organic matter and nutrients (nitrogen and phosphorous) from a synthetic wastewater with characteristics similar to those of a typical municipal wastewater. Response surface methodology based on central composite design was used to investigate the effects of nitrate recycle ratio, hydraulic retention time (HRT), and influent chemical oxygen demand (COD) on the organic and nutrient removal and optimization process. The optimized values of influent COD, HRT, and R were 462 mg/L, 10 h, and 3.52, respectively. The...