Sharif Digital Repository

Dam failure can result in a catastrophic break followed by a ood wave, often with considerable loss of life or property. One of the main causes of dam failure is loss of shear strength and the existence of discontinuity within the foundation. Dynamic analysis of concrete dams usually considered concrete behavior to be nonlinear and the foundation rock is assumed to be linear. In this study, seismic analysis of a concrete gravity dam was conducted to investigate the effect of the foundation on the nonlinear response. A finite element model of a dam-reservoir-foundation was considered to properly model the foundation as well as dam body nonlinear behaviors. An elasto-plastic formulation was... 

Hepatitis is one of the most perilous viral infectious diseases and many people suffer from it all around the world. In particular, hepatitis B is a terribly dangerous disease which may cause severe liver damage or cancer if it is not treated. Recently, several dynamic models have been developed from experimental studies for describing such diseases mathematically. The certainty of these dynamics models is questionable in realistic treatment processes. Thus, the modeling uncertainties should be considered in the dynamics, which necessitates employing robust control strategies capable to overcome these uncertainties. Accordingly, in this research, a control strategy is developed in order to... 

In the present paper, the nonlinear seismic behavior of a concrete gravity damreservoir- massed foundation system is studied focusing on the foundation material nonlinearity. For this purpose, a finite element program utilizing the elasto-plastic formulation for the foundation medium is provided considering the tensile and shear failure modes. Hoek-Brown and Mohr Coulomb criteria are used as the yield and plastic potential function of the shear failure mode, respectively; and in the tensile failure mode, various levels of the tensile strength are applied to the foundation. Bearing capacity is studied considering the localized plastic elements and forming the sliding path by plastic elements... 

A new robust adaptive controller is developed for the control of the hepatitis B virus (HBV) infection inside the body. The non-linear HBV model has three state variables: uninfected cells, infected cells and free viruses. A control law is designed for the antiviral therapy such that the volume of infected cells and the volume of free viruses are decreased to their desired values which are zero. One control input represents the efficiency of drug therapy in inhibiting viral production and the other control input represents the efficiency of drug therapy in blocking new infection. The proposed controller ensures the stability and robust performance in the presence of parametric and... 

In this paper, a nonlinear adaptive control method is presented for the treatment of the Hepatitis B Virus (HBV) infection. Nonlinear dynamics of the HBV, modeling uncertainties and three state variables (the numbers of uninfected and infected cells and free viruses) are taken into account. The proposed control law is designed for the antiviral drug input such that the number of free viruses and consequently the number of infected cells decrease to the desired values. An adaptation law is also presented to overcome modeling uncertainties by updating estimations of the system parameters during the treatment period. The stability of the process and convergence to desired state values are... 

A multistage decoder for the internally convolutionally coded fibre-optic time-hopping code division multiple access system recently introduced is considered. In this system, the decoder consists of several stages. The first stage is implemented using one of the single-user decoders introduced. The following stages are maximum likelihood (ML) decoders each of which use the decisions made by the previous stage. The performance of the proposed decoder is evaluated by a Monte Carlo simulation. Numerical results show that a multistage decoder with only two stages greatly outperforms the single-stage decoder with negligible increase in complexity. The authors also derive the Chernoff bound for... 

Metal organic frameworks (MOFs) UiO-66 (UiO stands for University of Oslo) and NH2-UiO-66 were prepared and characterized as sorbent (antidotal agents) for curcumin (CUR) adsorption. The structure of products were characterized by X-ray powder diffraction (XRD), Field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), Attenuated Total Reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and N2 adsorption–desorption measurements. FESEM showed NH2-UiO-66 displayed symmetrical crystals with triangular base pyramid morphology, with the particle size around 100 nm and uniform size distribution. Adsorption capacities of CUR/MOFs with different mass ratios... 

A low cytotoxic metal–organic framework (MOF) UiO-66 (UiO stands for University of Oslo) and NH2-UiO-66, that showed high cell viability of HFF-2 via 3-(4, 5-dimethylthiazol-2-yl) 2, 5-diphenyl tetrazolium assay, was reported as an effective adsorbent (antidotal) agents. The structure of MOFs was confirmed by Fourier transform infrared, Field emission scanning electron microscopy (FESEM) and X-ray diffraction. Thermal behavior of MOFs was investigated using with thermogravimetric analyzer in nitrogen atmosphere to check the thermal stability. FESEM showed NH2-UiO-66 displayed symmetrical crystals with triangular base pyramid morphology, with the particle size around 100 nm and uniform size... 

A low cytotoxic metal–organic framework (MOF) UiO-66 (UiO stands for University of Oslo) and NH2-UiO-66, that showed high cell viability of HFF-2 via 3-(4, 5-dimethylthiazol-2-yl) 2, 5-diphenyl tetrazolium assay, was reported as an effective adsorbent (antidotal) agents. The structure of MOFs was confirmed by Fourier transform infrared, Field emission scanning electron microscopy (FESEM) and X-ray diffraction. Thermal behavior of MOFs was investigated using with thermogravimetric analyzer in nitrogen atmosphere to check the thermal stability. FESEM showed NH2-UiO-66 displayed symmetrical crystals with triangular base pyramid morphology, with the particle size around 100 nm and uniform size... 

This paper is devoted to study the effects of pressure drop in heat exchangers on the dynamics of a free piston Stirling engine. First, the dynamic equations governing the pistons as well as the gas pressure equations for hot and cold spaces of the engine are extracted. Then, by substituting the obtained pressure equations into the dynamic relationships the final nonlinear dynamic equations governing the free piston Stirling engine are acquired. Next, effects of the gas pressure drop in heat exchangers on maximum strokes of the pistons and their velocities and accelerations are investigated. Furthermore, influences of pressure drop increase in the heat exchangers on maximum and minimum gas... 

Using multiple antennas at the transmit and receive sides of a passive radar brings both the benefits of MIMO radar and passive radar. However one of the obstacles arisen in such configuration is the receive antennas placement in proper positions so that the radar performance is improved. Here we just consider the case of positioning one receiver among multiple illuminators of opportunity. Indeed it is a start for the solution of optimizing the geometry of the multiple receivers in a passive radar  

SbCl3 supported on montmorillonite K-10 is an efficient catalyst for the ring opening of epoxides with aromatic amines under solvent-free conditions and microwave irradiation to give the corresponding b-amino alcohols in high yields with high regioselectivity  

In this paper, we consider an integrated sensing and communication (ISAC) system with wireless power transfer (WPT) where an unmanned aerial vehicle (UAV)-based radar serves a group of energy-limited communication users in addition to its sensing functionality. In this architecture, the radar senses the environment in phase 1 (namely sensing phase) and mean-while, the communications users (nodes) harvest and store the energy from the radar transmit signal. The stored energy is then used for information transmission from the nodes to UAV in phase 2, i.e., uplink phase. Performance of the radar system depends on the transmit signal as well as the receive filter; the energy of the transmit... 

One of the important obstacles in MIMO (Multiple Input Multiple Output) radars is the issue of designing proper transmit signals. Indeed, the capability of signal design is a significant advantage in MIMO radars, through which, the system can achieve much better performance. Many different aspects of this performance improvement have been considered yet, and the transmit signals have been designed to attain such goal, e.g., getting higher SNR or better detector's performance at the receiver. However, an important tool for evaluating the radar's performance is its ambiguity function. In this paper, we consider the problem of transmit signal design, in order to optimize the ambiguity function... 

Two gains play key roles in recently developed MIMO wireless communication systems: "spatial diversity" gain and "spatial multiplexing" gain. The diversity gain refers to the capability to decrease the error rate of the MIMO channel, while the multiplexing gain implicitly refers to the amount of increase in the capacity of the MIMO channel. It has been shown that there is a fundamental tradeoff between these two types of gains, meaning interplay between increasing reliability (via an increase in the diversity gain) and increasing data rate (via an increase in the multiplexing gain). On the other hand, recently, MIMO radars have attracted much attention for their superior ability to enhance... 

It is a well known fact that using multiple antennas at transmit and receive sides improves the detection performance. However, in such multiple-input multiple-output (MIMO) configuration, proper positioning of transmitters and receivers is a big challenge that can have significant influence on the performance of the overall system. In addition, determining the power of each transmitter under a total power constraint is a problem that should be solved in order to enhance the performance and coverage of such a system. In this paper, we design the Neyman-Pearson detector under the Rayleigh scatter model and use it to introduce a criterion for the antenna placement at both transmit and receive... 

There has been much interest, recently, towards exploiting the Multiple-Input Multiple-Output (MIMO) technique in radar. It is shown that using multiple antennas at transmit and receive sides can improve the performance of the system. However, in order to analyze the system's performance, its ambiguity function, i.e. the ambiguity function of a MIMO radar, is needed to be defined. In this paper, beginning from the information theoretic definitions, we derive such function, specifically for a MIMO radar with widely separated antennas  

By combining the two ideas of MIMO (Multiple Input Multiple Output) and PCL (Passive Coherent Location) in radar, one can achieve the advantages of both recently developed techniques simultaneously. While using multiple antennas at the receive side provides a spatial diversity of the object to be detected, using multiple illuminators of opportunity, most importantly, makes the radar covert to the interceptors. One obstacle in such MIMO configuration is choosing the positions of the receive antennas. In this paper, after analyzing the Neyman-Pearson detector for the DVB-T based PCL, we introduce the probability of missed detection as a criterion to place the receive antenna. Here, we only...