Sharif Digital Repository

Sentiment analysis plays a key role in companies, especially stores, and increasing the accuracy in determining customers’ opinions about products assists to maintain their competitive conditions. We intend to analyze the users’ opinions on the website of the most immense online store in Iran; Digikala. However, the Persian language is unstructured which makes the pre-processing stage very difficult and it is the main problem of sentiment analysis in Persian. What exacerbates this problem is the lack of available libraries for Persian pre-processing, while most libraries focus on English. To tackle this, approximately 3 million reviews were gathered in Persian from the Digikala website using... 

Although the role of individual ingredients of hot mix asphalt (HMA) such as asphalt binder and aggregates on its performance is readily recognized, there is only limited understanding about the interactions between these components and the properties of binder-aggregate interface. In order to study the interactions between asphalt binder and mineral aggregates, an interfacial test method was developed and its effectiveness was evaluated. Interfacial interactions were evaluated by testing thin films of an asphalt binder interfaced with the surface of aggregates under two different modes of loading in shear: sinusoidal oscillation and monotonically increasing. An Interaction Parameter (IP)... 

The thickness of shallow landslides is generally less than 2 m, which is of the same order of magnitude as the growth range of vegetation roots. Vegetation roots can improve the stability of shallow soil through mechanical and hydraulic effects. Therefore, the landslide process is closely related to the plant roots growing on the slope surface. Plant roots play a dominant role in the regulation of soil suction through solar radiation induced transpiration. However, little is known about the correlation between cumulative solar radiation and soil suction. Moreover, the specific effects of fine roots on the suction distribution are not clear in most previous studies. In this study, a vegetated... 

This paper reports on the NTIRE 2021 challenge on perceptual image quality assessment (IQA), held in conjunction with the New Trends in Image Restoration and Enhancement workshop (NTIRE) workshop at CVPR 2021. As a new type of image processing technology, perceptual image processing algorithms based on Generative Adversarial Networks (GAN) have produced images with more realistic textures. These output images have completely different characteristics from traditional distortions, thus pose a new challenge for IQA methods to evaluate their visual quality. In comparison with previous IQA challenges, the training and testing datasets in this challenge include the outputs of perceptual image... 

In this research, electrically performance, vibration/resonance characteristics, low-velocity impact, and absorbed energy of the piezoelectric doubly curved panel on the viscoelastic substrate is carried out. For modeling the contact force between the structure and impactor, Hertz contact theory is presented. Hamilton's principle and first-order shear deformation theory (FSDT) are presented for obtaining the governing and boundary condition equations of the structure under the low-velocity impact. Galerkin and Newmark solution procedures are presented for solving the governing equation in displacement, and time domains, respectively. This study's novelty is considering the effect of... 

Over the last decades, several approaches have been proposed in the literature to incorporate users' perceptions of travel costs, their bounded rationality, and risk-taking behaviors into network equilibrium modeling for traffic assignment problem. While theoretically advanced, these models often suffer from high complexity and computational cost and often involve parameters that are difficult to estimate. This study proposes an alternative approach where users' imprecise perceptions of travel times are endogenously constructed as fuzzy sets based on the probability distributions of random link travel times. Two decision rules are proposed accordingly to account for users' heterogeneous... 

Zeolitic imidazole frameworks (ZIFs) provide an exciting platform to design and fabricate non-precious-metal carbon-based catalysts for oxygen reduction/evolution reaction (ORR/OER). Herein, we elaborately design a facile enzyme-assisted synthetic strategy that enables to tailor the ZIFs precursors into structural stable decussation shape, which derived Co nanoislands grafted on decussate N-doped carbon nanoleaves (D-Co@NC) can well retain the interpenetrating nanostructure. Benefiting from the combined advantages of compositions and interpenetrating nanostructures, D-Co@NC possesses 5.2 times higher exposed electrochemical active area than the conventional dodecahedral one, thus endowing... 

In this paper, the interaction between various window specifications and different climate conditions is investigated. For this purpose, simultaneous effects of several aspects including glazing system, glass type, filling gas, glass thickness, window frame fraction, and interior shading are considered under three different climatic conditions. To evaluate the energy performance of various considered alternatives, the energy simulation of a base case building is evaluated in a computer environment. Using the validated model, the energy analysis is quantitatively performed, and cost-benefit analyses from the viewpoints of both residents and government are carried out based on the domestic and... 

Some tetra substituted derivatives of 2,2′ and 4,4′ bithiazoles have been synthesized and characterized in various solvents  

A mathematical time-dependent and isothermal model based on the grain model has been developed to simulate the kinetic and thermal behaviors of a porous iron oxide pellet undergoing chemical reactions with a mixture of hydrogen, carbon monoxide, carbon dioxide and water vapor. Its novelty consists in fact that it can deal with a multi-species reducing gas and oxide pellet. In spite of previous models in which the pure reductant was applied as reducing gas, this model can indicate an actual view of pellet reduction including the effects of reducing gas utility and reducing gas ratio. A finite volume fully implicit technique was applied for solving the governing equations. The model has been... 

In the present study, for the first time, a thermodynamically consistent large deformation theory is developed to model the multi physics problem of axonal swelling which is the hallmark of most of the brain diseases. To this end, the relevant axonal compartments are first explained and the corresponding model parts are introduced. Next, the problem is formulated as an open thermodynamic system and the corresponding constitutive and evolution equations are extracted utilizing the balance laws. Here, a multiplicative decomposition of the deformation gradient is used to capture the active behavior of the axonal actin cortex. Specific free energy functions are given for the model parts to... 

Rockfall is a significant hazard to sites that are located at the foot of rock slopes. In such sites, there is a notable need to evaluate the potential for rockfall, estimate the extent of areas at risk, and design retaining structures to reduce the risk of rockfall-induced. This paper presents a probabilistic framework for predicting the formation and progression of rockfalls and for evaluating the performance of retaining walls under rockfalls. To this end, first a probabilistic model for the rock projectile motion on a slope is presented. The model accounts for prevailing uncertainties, i.e., the trigger points, rock shape, projectile path, and slope material properties, which include... 

We report here a newly and facile synthesis of the phospholipids@gold nanoflowers (AuNFs) from intact cells as a new biomimetic organic-inorganic hybrid. The most appealing feature of this nanostructure is its dual-absorbing peak in near infrared (NIR) and visible region of spectra, which makes them a potential light-sensitive agent for reactive oxygen species (ROS)-induced apoptosis. Here, in contrast to previous studies, proposed nanostructures are synthesized in a one-pot reaction using phospholipids present in living cell membranes (as a donor cell) with detectable micro process of AuNF formation. The properties of the resulting AuNFs were evaluated through transmission electron... 

We study the asymmetric primordial fluctuations in a model of inflation in which translational invariance is broken by a domain wall. We calculate the corrections to the power spectrum of curvature perturbations; they are anisotropic and contain dipole, quadrupole, and higher multipoles with non-trivial scale-dependent amplitudes. Inspired by observations of these multipole asymmetries in terms of two-point correlations and variance in real space, we demonstrate that this model can explain the observed anomalous power asymmetry of the cosmic microwave background (CMB) sky, including its characteristic feature that the dipole dominates over higher multipoles. We test the viability of the... 

This paper presents an effective control scheme in dc microgrids to precisely share the load current oscillatory and dc components among distributed generation (DG) units. The proposed control strategy includes current and voltage control blocks. The current control block consists of oscillatory and dc current-sharing units. The main idea of the proposed method is to share the load current oscillatory and dc components among the DG units based on their rated power, by assigning appropriate output impedance values and droop coefficients to each DG unit. The voltage control block is a multiloop voltage control unit employed to control the microgrid voltage. The detailed model of the proposed... 

NiTi alloys have exhibited significant potential as a matrix of wear resistant composites. In this study, in order to examine the effect of starting materials on the wear performance of NiTi-based composites, both elemental Ni/Ti and prealloyed NiTi powders were used to fabricate NiTi-6wt% nano-Al2O3 composites using hot isostatic pressing (HIP). Nanoindentation and microhardness test results indicate that the composite samples produced from the elemental Ni/Ti powders exhibited higher hardness and lower pseudoelasticity properties than those of the samples fabricated from the prealloyed NiTi powders; this is attributed to the higher amount of... 

The adhesion and mechanical properties of hydrogels used for vascular wound repair often deteriorate dramatically on wet surfaces, resulting in ineffective repair. In this work, a poly(N-isopropyl acrylamide-co-dopamine methacrylamide) nanogel with dopamine groups was synthesized and introduced into a polyacrylamide (PAAm) hydrogel to produce temperature-responsive hydrogels, which greatly improved mechanical and adhesive properties of PAAm hydrogels. Nanogel-reinforced PAAm (NR-PAAm hydrogel) can adhere to the surface of various solid materials and biological tissues through special physical interactions, which exhibited different mechanical and adhesion properties as temperature changes... 

Deployment of low-power low-cost small access points such as femtocell access points (FAPs) constitute an attractive solution for improving the existing macrocell access points' (MAPs) capacity, reliability, and coverage. However, FAP deployment faces challenging problems such as interference management and the lack of flexible frameworks for deploying the FAPs by the service providers (SPs). In this paper, we propose a novel solution that jointly associates the user equipment (UE) to the APs, and allocates the FAPs to the SPs such that the the total satisfaction of the UEs in an uplink OFDMA network is maximized. We model the competitive behaviors among the UEs, FAPs, and SPs as a dynamic... 

In this study, the enhanced trichloroethylene (TCE) degradation performance was investigated by polyvinyl alcohol coated calcium peroxide nanoparticles (PVA@nCP) as an oxidant in Fe(II)-based catalytic systems. The nanoscale iron sulfide (nFeS), having an average particle size of 115.4 nm, was synthesized in the laboratory and characterized by SEM, TEM, HR-TEM along with EDS elemental mapping, XRD, FTIR, ICP-OES, and XPS techniques. In only ferrous iron catalyzed system (PVA@nCP/Fe(II)), TCE degradation was recorded at 58.9% in 6 h. In comparison, this value was increased to 97.5% or 99.7% with the addition of citric acid (CA) or nFeS in PVA@nCP/Fe(II) system, respectively. A comparative... 

In this study, the enhanced trichloroethylene (TCE) degradation performance was investigated by polyvinyl alcohol coated calcium peroxide nanoparticles (PVA@nCP) as an oxidant in Fe(II)-based catalytic systems. The nanoscale iron sulfide (nFeS), having an average particle size of 115.4 nm, was synthesized in the laboratory and characterized by SEM, TEM, HR-TEM along with EDS elemental mapping, XRD, FTIR, ICP-OES, and XPS techniques. In only ferrous iron catalyzed system (PVA@nCP/Fe(II)), TCE degradation was recorded at 58.9% in 6 h. In comparison, this value was increased to 97.5% or 99.7% with the addition of citric acid (CA) or nFeS in PVA@nCP/Fe(II) system, respectively. A comparative...