Sharif Digital Repository

Biosensors could be used as digital devices to measure the sample infield. Consequently, computational programming along with experimental achievements are required. In this study, a novel biosensor/artificial neural network (ANN) integrated system was developed. Poly (3,4-ethylenedioxy-thiophene)(PEDOT), graphene oxide nano-sheets (GONs) and laccase (Lac) were used to construct a biosensor. The simple and one-pot process was accomplished by electropolymerizing 3,4-ethylenedioxy-thiophene (EDOT) along with GONs and Lac as dopants on glassy carbon electrode. Scanning electron microscopy (SEM) and electrochemical characterization were conducted to confirm successful enzyme entrapment. The... 

One of the challenging questions in cosmology is the nature of dark matter particles. Fuzzy dark matter (FDM) is one of the candidates which is made of very light (mFDM≃10-22-10-21 eV) bosonic particles with no self-interaction. It is introduced by the motivation to solve the core-cusp problem in the galactic halos. In this work, we investigate the observational features from FDM halo collisions. Taking into account the quantum wavelength of the condensed bosonic structure, we determine the interference of the wave function of cores after collision. The fringe formation in the wave function is associated to the density contrast of the dark matter inside the colliding galaxies. The... 

Fuzzy dark matter (FDM) is one of the recent models for dark matter. According to this model, dark matter is made of very light scalar particles with considerable quantum mechanical effects on the galactic scale, which solves many problems of cold dark matter (CDM). Here we use the observed data from the rotation curve of the Milky Way (MW) Galaxy to compare the results from FDM and CDM models. We show that FDM adds a local peak on the rotation curve close to the center of the bulge, where its position and amplitude depend on the mass of FDM particles. By fitting the observed rotation curve with our expectation from FDM, we find that the mass of FDM is m=2.5-2.0+3.6×10-21 eV. We note that... 

This paper introduces a new passive control device for protecting structures against earthquakes. The device consists of two welded pipes which have two smaller pipes inside them and the spaces between the pipes are filled with metals such as lead or zinc. The device is loaded in shear and takes advantage of plastification of the outer pipes, the inner pipes and the infilled metals, and the friction between metals as energy absorption mechanisms. Quasi-static cyclic tests are performed on six specimens all showing stable hystereses and high damping. A finite element model is developed and calibrated against test results. The model is used to find the optimum sizes of pipes needed for a... 

In this paper, the dynamic characteristics of skewed bridges are explored analytically. Closed form solutions for translational and torsional periods of free vibration and mode shapes are given for slab-girder skewed bridges. Moreover, the seismic displacement of the deck of skewed bridges is calculated using the response spectrum method and its skew term is compared with the requirement of AASHTO. The effects of seismic force resisting elements, such as elastomeric bearings and end diaphragms are included. It is shown that the skew term in AASHTO's equation can underestimate the seat width requirement for some bridges. A new skew term for the bridge seat width requirement is suggested  

In this paper, a new passive earthquake energy dissipative device, called the dual-pipe damper (DPD), is introduced, tested and analytically studied. The device consists of two pipes welded at selected locations and loaded in shear. The inelastic cyclic deformation dissipates energy mainly through flexure of the pipe body. However, at large displacements a tension diagonal forms in the middle of the device which further adds to stiffness and strength. The strength, stiffness and energy dissipation of the DPD is more than two single pipe dampers that were previously studied. Cyclic quasi-static tests were performed on four samples of DPD. Excellent ductility, energy absorption and stable... 

In this paper the behavior of steel pipes, filled and unfilled with concrete, is studied under cyclic shear to examine the possibility of their use as a seismic damper. Two specimens of steel pipes filled inside with concrete are tested under monotonic and cyclic shear. Four other specimens ofbare steel pipes are tested under fully reversed cyclic shear loading. The results show that the bare steel pipes are capable of absorbing a great amount of energy under a severe cyclic shear loading with a stable hysteretic behavior. This behavior is also simulated using the finite element method. Then, parametric studies are performed to investigate the effects of variations in geometrical properties... 

Theoretical and experimental verification of the pipe damper was investigated in Part I of the two companion papers. In this paper, the application of the pipe damper to structures is examined. In particular, single span slab-girder bridges are considered for analytical investigations. A practical detail for the installation of the pipe damper is introduced. Nonlinear dynamic time history analyses are conducted on bridges equipped with the pipe damper and the results are compared with ordinary bridges. Bridge span, ground motion and the pipe length are varied in the analyses. Results show that the pipe damper is a reliable and economical metallic-yielding device that can easily be installed... 

In this paper, a simple finite element model for seismic analysis of retaining walls is introduced. The model incorporates nonlinearity in the behavior of near wall soil, wall flexibility and elastic free field soil response. This model can be employed in nonlinear modeling of retaining walls and bridge abutments. The advantages of this model are simplicity and flexibility in addition to acceptable precision. Using this finite element model, an analytical study is conducted on several soil-wall systems using nonlinear time-history analysis by applying real earthquake records. Based on the results of these analyses, new seismic soil pressure distributions are proposed for different soil and... 

In composite beams, shear connectors are commonly used to transfer longitudinal shear forces across the steel-concrete interface. This paper presents an experimental study on the behavior of channel shear connectors embedded in a solid concrete material slab under monotonic and low-cycle fatigue loading. The latter would be applicable to composite structures subjected to seismic events. Of specific interest are the behavior and effects of different concrete materials. A series of push-out specimens made of plain concrete, reinforced concrete (RC), fiber reinforced concrete (FRC) and engineered cementitious composite (ECC) were tested for this evaluation. The results show that the reversed... 

In this second part of the two companion papers an effective numerical model is proposed using finite element method to simulate the push-out test of channel shear connectors. The focus is on the shear capacity of channel shear connectors embedded in a solid reinforced concrete slab under monotonic loading. The model has been validated against test results presented in Part (I) and compared with data given in North American design codes. Parametric studies using this nonlinear model are performed to investigate the variations in concrete strength, channel dimensions and the orientation of the channel. The results show that the concrete strength, web and flange thicknesses of the channel and... 

In response to the imperfections of current sequence alignment methods, originated from the inherent serialism within their corresponding electrical systems, a few optical approaches for biological data comparison have been proposed recently. However, due to their low performance, raised from their inefficient coding scheme, this paper presents a novel all-optical high-throughput method for aligning DNA, RNA, and protein sequences, named HELIOS. The HELIOS method employs highly sophisticated operations to locate character matches, single or multiple mutations, and single or multiple indels within various biological sequences. On the other hand, the HELIOS optical architecture exploits... 

To address one of the most challenging industry problems, we develop an enhanced training algorithm for anomaly detection in unlabelled sequential data such as time-series. We propose the outputs of a well-designed system are drawn from an unknown probability distribution, U, in normal conditions. We introduce a probability criterion based on the classical central limit theorem that allows evaluation of the likelihood that a data-point is drawn from U. This enables the labelling of the data on the fly. Non-anomalous data is passed to train a deep Long Short-Term Memory (LSTM) autoencoder that distinguishes anomalies when the reconstruction error exceeds a threshold. To illustrate our... 

Composite steel tub girders are proven to be an economical choice for long span bridges. However, detailed analysis of such superstructures requires extensive Finite Element (FE) modeling that includes many internal and external diaphragms. This paper is an attempt to study diaphragms and interior cross frames in tub girders and present simplified FE modeling details for the tub girder superstructures under gravity and seismic loadings incorporating accurate end diaphragm and interior cross frame stiffness equations. The simplified model is applicable to design of new tub girder bridges as well as load rating, health monitoring and retrofitting of existing bridges which require more... 

In this research, a manufacturing facility with independent workstations to remanufacture nonconforming products is investigated. Each workstation is first modeled as an M/M/m queuing system with m being a decision variable. Then, a tri-objective integer nonlinear programming models is developed to formulate the problem. The first objective tries to minimize the waiting times of products, while the second one tries to maximize the minimum reliability of machines at the workstations. Since minimization of the waiting times results in using a large number of machines with higher idle times, the third objective is considered to minimize the mean idle time of the machines. The aim is to... 

Quantum metrology employs nonclassical systems to improve the sensitivity of measurements. The ultimate limit of this sensitivity is dictated by the quantum Cramér–Rao bound. On the other hand, the quantum speed limit bounds the speed of dynamics of any quantum process. We show that the speed limit of quantum dynamics sets a fundamental bound on the minimum attainable phase estimation error through the quantum Cramér–Rao bound, relating the precision directly to the underlying dynamics of the system. In particular, various metrologically important states are considered, and their dynamical speeds are analyzed. We find that the bound could, in fact, be related to the nonclassicality of... 

In this paper, performance of grid computing environment is studied in the presence of failure-repair of the resources. To achieve this, in the first step, each of the grid resource is individually modeled using Stochastic Reward Nets (SRNs), and mean response time of the resource for grid tasks is computed as a performance measure. In individual models, three different scheduling schemes called random selection, non-preemptive priority, and preemptive priority are considered to simultaneously schedule local and grid tasks to the processors of a single resource. In the next step, single resource models are combined to shape an entire grid environment. Since the number of the resources in a... 

This paper presents an optical processing approach for exploring a large number of genome sequences. Specifically, we propose an optical correlator for global alignment and an extended moiré matching technique for local analysis of spatially coded DNA, whose output is fed to a novel three-dimensional artificial neural network for local DNA alignment. All-optical implementation of the proposed 3D artificial neural network is developed and its accuracy is verified in Zemax. Thanks to its parallel processing capability, the proposed structure performs local alignment of 4 million sequences of 150 base pairs in a few seconds, which is much faster than its electrical counterparts, such as the... 

This paper presents a novel optical processing approach for exploring genome sequences built upon an optical correlator for global alignment and the extended dual-vector-curve-curve (DV-curve) method for local alignment. To overcome the problem of the traditional DV-curve method for presenting an accurate and simplified output, we propose the hybrid amplitude wavelength polarization optical DV-curve (HAWPOD) method, built upon the DV-curve method, to analyze genome sequences in three steps: DNA coding, alignment, and post-Analysis. For this purpose, a tunable graphene-based color filter is designed for wavelength modulation of optical signals. Moreover, all-optical implementation of the... 

Micro-mixers are considered as vital components of Micro Total Analysis systems (μTAS). Major objective in the design of micro-mixers is achieving high mixing quality in short mixing times. In this paper, numerical simulation of some micro-mixer designs has been carried out to understand the detailed flow pattern and thereby to propose modifications for improving mixing efficiency. It is well known that inducing convection will provide turbulent like behavior with corresponding mixing enhancement. In micro systems to drive the flow, electro-osmotic force is usually used by introducing electrodes. In this work, mixing electrodes have been implemented to induce convection and eddies. This...