Sharif Digital Repository

Studies on corrugated steel shear walls (CSSWs) generally indicate noticeable increase of energy absorption, as well as increasing shear buckling capacity of corrugated plates being more likely rather than the flat plates. In this paper, the effect of variation in the angle of trapezoidal plate on the behavior of CSSWs has extensively been investigated. Three specimens of CSSW with 1 story and single bay in half scale are tested under cyclic load. The observations of experiment do indicate that stress concentration has been increased in the corner of subpanels, by increasing of the corrugation angle. Development of the tensile field and wall yield and damage depends on the geometry of the... 

Different ways have been presented to prevent elastic buckling of steel shear walls. One of these solutions is corrugated shear wall. In this type of wall, shear buckling strength increases without increasing the thickness of the panel. Numerical modeling results indicate that, always, shear buckling strength of corrugated panels is more than the flat panels and with the right choice of the geometric parameters of corrugated panels; without increasing the thickness of the panel, we can improve buckling strength significantly. In the trapezoidal corrugated panels, reducing the width of the subpanels do not always increase buckling strength of the panel, but it changes the panel buckling shape... 

Gold (Au) nanoparticles are widely used in diagnosing cancer, imaging, and identification of therapeutic methods due to their particular quantum characteristics. This research presents different types of aqueous models and potentials used in TIP3P, to study the effect of the particle size and density of Au clusters in aquatic environments; so it can be useful to facilitate future investigation of the interaction of proteins with Au nanoparticles. The EAM potential is used to model the structure of gold clusters. It is observed that in the systems with identical gold/water density and different cluster radii, gold particles are distributed in aqueous environment almost identically. Thus, Au... 

In this paper, the performance of the benzene gas detection sensor in the air is optimized by an experimental design method. So in this work, Nanostructured thin films of ZnO and Zn2SnO4 were prepared in wurtzite form via a facile atmospheric pressure chemical vapor deposition (CVD) method, using metallic zinc and tin precursors. Characterization of the gas sensor was performed by using Powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and surface area analysis (using BET method). The results show that Zn2SnO4 nanowire network exhibited good sensitivity at 299 °C temperature to low concentrations (100 ppb) of Benzene which can be potentially used as a resistive gas sensor.... 

Numerous studies yet have been carried out on downscaling of the large-scale climate data using both dynamical and statistical methods to investigate the hydrological and meteorological impacts of climate change on different parts of the world. This study was also conducted to investigate the capability of feedforward neural network with error back-propagation algorithm to downscale the provincial segmentation of Iran (30 provinces) on a daily scale. This model was proposed for the downscaling daily temperature, precipitation and wind speed data, and it was calibrated and verified by using the daily outputs derived from the National Center for Environmental Prediction (NCEP) database... 

Connected and autonomous vehicles (CAVs) have the potential to drastically change the structure of future cities and regions. Researchers predict different outcomes to result from the emergence of CAV technology. While some see their potential as amounting to a complete overhaul of the transport system, others predict the technology will be slow to be adopted and may face competition from other mobility options such as drones. Therefore, the future can be viewed along a spectrum, ranging from no CAVs to a fully driverless transport system. This paper presents an overview of the past attempts on studying CAVs and their impacts to provide a comprehensive view about possible futures with CAVs.... 

Adomian decomposition method was employed to obtain an approximate solution to two-dimensional and axisymmetric jet impinging flows in this work. Assumptions have been made to reduce the related full Navier-Stokes equations to a non-linear ordinary differential equation. A trial and error strategy has been used to obtain the constant coefficient in the approximated solution. Velocity Profiles, Shear stresses and displacement thickness were chosen to be compared with accurate numerical data. Sensitivity of the results to the number of terms have been discussed. The results showed for open boundary problems having at least one boundary condition at infinity, the applicable range of the... 

The effects of the residual stress field resulting from shot peening and the indentation technique were investigated in relation to fatigue crack closure and crack growth behaviour. Compact Specimens of 20NiCrMo2 were used in this investigation. The regions of residual stress field were located behind the fatigue crack tip. Crack closure behaviour was measured with back face strain and crack mouth opening displacement gauges. Crack length was monitored by the compliance and microscopic methods. Residual stress was measured by the incremental hole-drilling method. Subsequently the closure level, propagation rate and resulting crack growth retardation were studied. Crack closure and attendant... 

The polysaccharide, kappa-carrageenan (κC) was chemically modified to achieve a novel superabsorbent hydrogel via graft copolymerization of methacrylamide (MAM) onto the substrate followed by alkaline hydrolysis. Ammonium persulfate (APS) and N,N′-methylene bisacrylamide (MBA) were used as a free-radical initiator and a crosslinker, respectively. The saponification reaction was carried out using sodium hydroxide aqueous solution. Either κC-g-PMAM or hydrolyzed κC-g-PMAM (PMAM: polymethacrylamide) was characterized by FT-IR spectroscopy. The effect of grafting variables (i.e. concentration of MBA, MAM, and APS) and alkaline hydrolysis conditions (i.e. NaOH concentration, hydrolysis time and... 

To synthesize a novel biopolymer-based superabsorbent hydrogel, 2-acrylamido-2-methylpropanesulfonic acid (AMPS) was grafted onto kappa-carrageenan (KC) backbones. The graft copolymerization reaction was carried out in a homogeneous medium and in the presence of ammonium persulfate (APS) as an initiator, N,N,N',N'-tetramethyl ethylenediamine (TMEDA) as an accelerator, and N,N'-methylene bisacrylamide (MBA) as a crosslinker. A proposed mechanism for KC-g-AMPS formation was suggested and the hydrogel structure was confirmed using FTIR spectroscopy. The affecting variables on swelling capacity, i.e., the initiator, the crosslinker, and the monomer concentration, as well as reaction temperature,... 

In this study, a series of highly swelling hydrogels based on sodium alginate (NaAlg) and polymethacrylamide (PMAM) was prepared through free radical polymerization. The graft copolymerization reaction was performed in a homogeneous medium and in the presence of ammonium persulfate (APS) as an initiator andN,N′-methylenebisacrylamide (MBA) as a crosslinker. The crosslinked graft copolymer, alginate-graft-polymethacrylamide (Alg-g-PMAM), was then partially hydrolyzed by NaOH solution to yield a hydrogel, hydrolyzed alginate-graft-polymethacrylamide (H-Alg-g-PMAM). During alkaline hydrolysis, the carboxamide groups of Alg-g-PMAM were converted into hydrophilic carboxylate anions. Either the... 

Herein, the graphene oxide (GO)/cobalt ferrite nanoparticles were used to apply the heat treatment on the breast cancer cell line of MCF7. The synthesized nanoparticles were evaluated before in vitro and in vivo studies, using transmission electron microscopy (TEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), thermal property and relaxivity measurement. The nanoparticles showed a diameter of 5 nm with the ferrimagnetic property. Also, the nanoparticles were well distributed on the GO nanosheets. The related peaks of cobalt ferrite nanoparticles were approved by using XRD and XPS assays. During the in vitro investigations, IC50 with... 

This letter presents a Ka-Band 0.1-μm GaAs pHEMT Power Amplifier with broad bandwidth. The isolating backvia wall (IBVW) has been proposed to improve the stability and performance. Over the frequency band of 31-40 GHz, implemented PA delivers 5 W saturated output power, 28% maximum power added efficiency (PAE) and 20 dB maximum small-signal gain. The chip size of the PA is 11.9 mm2. To the best of authors knowledge, the presented PA demonstrates widest bandwidth in Ka-band GaAs PAs while maintaining compact size  

Among polymers, polyaniline (PANi) has been introduced as a good candidate for muscle regeneration due to high conductivity and also biocompatibility. Herein, for the first time, we report the use of electrospun nanofibrous membrane of PAN-PANi as efficient scaffold for muscle regeneration. The prepared PAN-PANi electrospun nanofibrous membrane was characterized by scanning electron microscopy (SEM), Attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR) and tensile examination. The softer scaffolds of non-composite electrospun nanofibrous PAN govern a higher rate of cell growth in spite of lower differentiation value. On the other hand, PAN-PANi electrospun... 

The energy of a graph G, E(G), is the sum of absolute values of the eigenvalues of its adjacency matrix. Gutman et al. proved that for every cubic graph of order n, E(G)≥n. Here, we improve this result by showing that if G is a connected subcubic graph of order n≥8, then E(G)≥1.01n. Also, we prove that if G is a traceable subcubic graph of order n≥8, then E(G)>1.1n. Let G be a connected cubic graph of order n≥8, it is shown that E(G)>n+2. It was proved that if G is a connected cubic graph of order n, then E(G)≤1.65n. Also, in this paper we would like to present the best lower bound for the energy of a connected cubic graph. We introduce an infinite family of connected cubic graphs whose for... 

Let G be a graph. The first and second Zagreb index of G is defined as M1(G)= Σ degG(V)2 and M2(G)= Σ degG(u)degG(V) respectively. In this paper we compute Zagreb indices of chain graphs