Sharif Digital Repository

Ant colony optimization (ACO) is a well-known metaheuristic in which a colony of artificial ants cooperate in exploring good solutions to a combinatorial optimization problem. In this paper, an ACO algorithm is presented for the graph coloring problem. This ACO algorithm conforms to max-min ant system structure and exploits a local search heuristic to improve its performance. Experimental results on DIMACS test instances show improvements over existing ACO algorithms of the graph coloring problem  

In this study, sintered porous polymeric materials made of high density polyethylene (HDPE) were fabricated through controlling the chain interdiffusion time at the transition temperature of semicrystalline and melt states. At this intermediate state, where both crystalline and amorphous phases coexist, the interfacial welding of HDPE particles is facilitated thanks to interdiffusion caused by chain relaxation phenomena. Then, by assuming a spherical shape and a cubic packing configuration of particles, a geometrical model was developed to predict porosity variations as sintering progresses. Moreover, the HDPE used, as a broad molecular weight distributed polymer, has different family chains... 

Sintering process at temperature intervals close to the melting point of polymers is greatly important due to its role in synthesizing porous materials. During sintering, particles of polymeric materials coalesce throughout a process called interdiffusion. On the contrary, crystallization strongly affects the interdiffusion process at temperature intervals below and close to the melting point. Apparently, the outcome of the contention between these two factors would determine the interfacial width. Therefore, the current study presents a model, which takes both crystallization and interdiffusion into account, to predict sintering kinetic. Consequently, interfacial strength was assessed with... 

In the present study, a novel α-MnO2/AgI photocatalyst was successfully fabricated by using hydrothermal/precipitation methods, and its photocatalytic performance was evaluated from the degradation of Acid blue 92 (AB92) dye under visible light irradiation. The surface and crystalline structure, morphology, and electro-chemical properties of the as-made photocatalyst were investigated by BET, XRD, XPS, SEM-EDS, TEM, DRS, PL, PC, and Raman analysis. The optimized nanocomposite (α-MnO2/AgI) with a weight ratio of 1:15 showed the best photocatalytic activity in the decomposition of AB92 with a removal efficiency of 100% in 40 min which was better than that of pure α-MnO2 (48%) and AgI (61%),... 

In the present work, the novel ternary Fe2O3/MoO3/AgBr photocatalyst with different dosages of AgBr was successfully synthesized via a facile method. The physicochemical properties of the resultant catalyst were characterized by using various techniques such as XRD, SEM, EDX, BET, XPS, DRS, and VSM. The photocatalytic performance of as-prepared samples was evaluated by degradation of organic dye acid blue 92 (AB92) under visible light irradiation, and in dark. The impact of different operating parameters namely calcination temperature, amount of photocatalyst, dye concentration, and pH of solution were investigated in degradation reaction. Ternary nanocomposite exhibited the best... 

The control of texture and microstructure can be achieved by an appropriate thermomechanical treatment in industrial production. The effects of finish rolling temperature, cold reduction and annealing temperature on texture development and microstructure in Brass sheet were investigated. The role of deformation inhomogeneities on texture evolution has been considered. The formation of transition bands during hot rolling enforced the intensity of cube components. Shear bands increased the intensities of S and Cu components after cold rolling and at higher cold reductions. Transition from Cu to Y and Y to Bs was completed better because of mechanical twinning. Thermal twins annihilated the... 

A novel ɑ-NiMoO4/ɑ-MoO3 binary nanocomposite was fabricated by using facile method. The fabricated nanocomposite was characterized by various techniques, and the photocatalytic activity was evaluated in degradation of Acid blue 92 dye. Among of as-made photocatalysts with various weight ratios of ɑ-MoO3, ɑ-NiMoO4/ɑ-MoO3 (1:5%w/w) exhibited the best photocatalytic performance, and selected as optimum photocatalyst. Under optimum reaction conditions ([dye] = 10 mg L−1, [catalyst] = 200 mg L−1, and pH = 7.0), complete removal efficiency was obtained within 100 min. Also, the first-order rate constant value of reaction in the presence of ɑ-NiMoO4/ɑ-MoO3 was calculated to be 0.032 min−1 that was... 

Ant Colony Optimization (ACO) is a well-known metaheuristic in which a colony of artificial ants cooperate in exploring good solutions to a combinatorial optimization problem. In this paper, an ACO algorithm is presented for the graph coloring problem. This ACO algorithm conforms to Max-Min Ant System structure and exploits a local search heuristic to improve its performance. Experimental results on DIMACS test instances show improvements over existing ACO algorithms of the graph coloring problem  

Dust deposition on the surface of solar systems is one of the main parameters that significantly affects the performance of such systems. In this study, the effect of dust deposition density on the performance of photovoltaic modules (PV) and photovoltaic-thermal systems (PVT) is numerically investigated. Accordingly, all layers of a monocrystalline silicon PV module for both systems are simulated. Moreover, the effect of various system parameters on the performance of both clean and dusty PV module and PVT system are studied. The studied parameters included: solar radiation intensity, ambient temperature, coolant inlet temperature, and coolant inlet velocity. The obtained results indicate... 

In this study, the performance of a Photovoltaic Thermal-Organic Rankine Cycle (PVT-ORC) system combined with a Proton Exchange Membrane Electrolysis Cell (PEMEC) is investigated. A combined numerical/theoretical model of the system is developed and used to evaluate the effect of various system design parameters. In addition, the effects of using water, ethylene glycol, and a mixture of water and ethylene glycol (50/50) as the working fluid of the PVT system and R134a, R410a, and R407c as the working fluid of the ORC cycle on the performance of the PVT-ORC-PEMEC system are studied. Based on the results, R134a and water demonstrated the best performance as the working fluid of the ORC and PVT... 

Background: Convolutional neural networks (CNN) have enabled significant progress in speech recognition, image classification, automotive software engineering, and neuroscience. This impressive progress is largely due to a combination of algorithmic breakthroughs, computation resource improvements, and access to a large amount of data. Method: In this paper, we focus on the automated detection of autism spectrum disorder (ASD) using CNN with a brain imaging dataset. We detected ASD patients using most common resting-state functional magnetic resonance imaging (fMRI) data from a multi-site dataset named the Autism Brain Imaging Exchange (ABIDE). The proposed approach was able to classify ASD... 

The earned value management (EVM) model is an essential technique for managing and forecasting project features such as scheduling and cost performances indexes. This paper presents a novel fuzzy earned-value model based on Z-number theory incorporating both the impreciseness of real life conditions and a degree of reliability through considering an expert judgment process. The latter factor has not been used by other researchers in the field. The proposed model provides a reliable assessment for the progress performance of a project and its 'at completion' cost in an uncertain environment. Finally, an illustrative case demonstrates the applicability of the proposed model in real life... 

In project management context, the Earned Value Management (EVM) is a well-known technique. Despite its popularity, the standard EVM suffers from the absence of some features that require being focused further on to make this method more efficient. This paper is addressing such features specifically the financial aspects of cost control system. These aspects that have been absent in the standard EVM include the time value of money, delay in client payment and contractor cash flow in uncertain environment. The proposed model here utilizes fuzzy sets to deal with the uncertain conditions of real projects. It attempts to extend the theoretical framework of EVM to evaluate and control the... 

The mechanism of selectivity in ion channels is still an open question in biology for more than half a century. Here, we suggest that quantum interference can be a solution to explain the selectivity mechanism in ion channels since interference happens between similar ions through the same size of ion channels. In this paper, we simulate two neighboring ion channels on a cell membrane with the famous double-slit experiment in physics to investigate whether there is any possibility of matter-wave interference of ions via movement through ion channels. Our obtained decoherence timescales indicate that the quantum states of ions can only survive for short times, i.e. ∼100 picoseconds in each...