Sharif Digital Repository

Nonlinear numerical modeling of masonry-infilled frames is one of the most complicated problems in structural engineering field. This complexity is attributed to the existence of joints as the major source of weakness and material nonlinearities as well as the infill-frame interaction which cannot be properly modeled using the traditional finite element methods. Although there are many numerical studies available on solid masonry-infilled steel frames' behavior, however, few researches have been conducted on infilled frames with openings. In this paper a two-dimensional numerical model using the specialized discrete element method (DEM) software UDEC (2004) is developed for the nonlinear... 

Position sensorless control of ac machines at zero and low speed is possible using high-frequency carrier injection methods. These methods utilize anisotropic properties of rotor. Therefore, they may lose their efficiency for nonsalient machines or machines with small rotor saliency. In these machines, measurement noise and offset, existing delays, as well as model uncertainties may lead to inaccurate estimation of rotor position. Stator resistance which is usually neglected in these methods may also lead to a considerable error especially in machines with small rotor saliency. In this paper, a new position estimation method is presented, and it is shown that in comparison to conventional... 

Given the importance and complexity of the three-dimensional (3D) neutron transport equation solution, in the current research, a new Modular Ray Tracing (MRT) Algorithm and 3D characteristic kernel for heterogeneous structures are presented. Improvement of memory management and cache coherency are achieved to some acceptable level. Also, parallel implementation of transport algorithm utilizing OpenMP, cause significant reduction in runtime. To validate our Algorithm, first, a self-constituted pin cell and a lattice arrangement are modeled and results are compared with Monte-Carlo simulation. Second, the well-known 3D benchmark, Takeda model one and two, are investigated and results compared... 

Control charts are useful tools of monitoring quality characteristics. One of the problems of employing a control chart is that the time it alarms is not synchronic with the time when assignable cause manifests itself in the process. This makes difficult to search and find assignable causes. Knowing the real time of manifestation of assignable cause (change point) helps to find assignable cause(s) sooner and eases corrective actions to be taken. In this paper, a probabilistic neural network (PNN)-based procedure was developed to estimate the variance change point of a normally distributed quality characteristic. The PNN was selected based on trial and error among different types of... 

A substantial part of this paperwas published in volume 8755 of the series LectureNotes in Computer Science, page 11–22, Title of the book: Social Robotics, 6th International Conference, ICSR 2014, Sydney, NSW, Australia, October 27–29, 2014, ISBN: 978-3-319-11972-4, article title: Impact of a Social Humanoid Robot as a Therapy Assistant in Children Cancer Treatment, by Minoo Alemi, Ali Meghdari, Ashkan Ghanbarzadeh, Leila Jafari Moghadam and Anooshe Ghanbarzadeh. The authors apologize for not having referenced to the previously published article  

In this work a novel unbreakable sol-gel-based in-tube device for on-line solid phase microextraction (SPME) was developed. The inner surface of a copper tube, intended to be used as a high performance liquid chromatography (HPLC) loop, was electrodeposited by metallic Cu followed by the self assembled monolayers (SAM) of 3-(mercaptopropyl) trimethoxysilane (3MPTMOS). Then, poly (ethyleneglycol) (PEG) was chemically bonded to the -OH sites of the SAM already covering the inner surface of the copper loop using sol-gel technology. The homogeneity and the porous surface structure of the SAM and sol-gel coatings were examined using the scanning electron microscopy (SEM) and adsorption/desorption... 

High-performance wearable electronic devices with the capability of converting mechanical force into electrical energy have been gaining increasing attention for biomedical monitoring applications. We present a novel wearable piezoelectric sensor based on a poly(vinylidene fluoride) (PVDF) nanofibrous membrane containing microporous zirconium-based metal-organic frameworks (MOFs) for arterial pulse monitoring. It is shown that the incorporation of 5 wt % of MOF greatly enhances the piezoelectric constant of the polymer fibrous mat by 3.4-fold without significant loss in its flexibility. The nanofibrous composite exhibits a peak-to-peak voltage of 600 mV under an applied force of 5 N, which... 

Fiber/matrix debonding at the free surface of unidirectional composites deteriorates their performance and ultimately reduces the working life of these materials. Identifying the source, controlling the propagation and elimination of the damages has been the subject of many research attempts. The results show that the singular radial thermal residual stress at the fiber/matrix interface on the free surface of composites is the main reason for initiation of the debonding. Also, it has been experimentally and numerically proven that a thin layer of matrix-like cover on the free surface could highly help in elimination and/or reduction of the damage. However, the results were limited to the... 

Treatment of cancer involves many invasive procedures that could be a source of distress in kids suffering from cancer. Distress itself can be an important obstacle in patients' acceptance of treatment and their adaptation to it, consequently reducing its efficiency. Distress symptoms, in a spectrum from mild to critical, are shown to be widespread in children struggling with cancer. In recent years to alleviate this psychological condition, researchers have proposed and examined several methods such as relaxation, hypnosis, desensitization, and distraction. This study presents a new approach to explore the impact of utilizing a humanoid robot as a therapy-assistant in dealing with patients'... 

Treating cancer encompasses many invasive procedures that can be a source of distress in oncology patients. Distress itself can be a major obstruction in the path of acceptance of treatment and the patient's adaptation to it, thereby reducing its efficiency. These distress symptoms have been found to be prevalent in children suffering from cancer, in a spectrum from mild to critical. In the past years in response to this psychological suffering, researchers have proposed and tested several methods such as relaxation, hypnosis, desensitization, and distraction. This paper propounds a new approach by exploring the effect of utilizing a humanoid robot as a therapy-assistive tool in dealing with... 

A novel technique based on image processing inspired by the simple assumption for the first time to assess the roughness of nanofibrous mats based on grayscale variations is proposed. The height of a nanofibrous mat in different regions of the surface is simulated by grayscale variations in the image while the relation between grayscale and height is obtained as a linear function. The roughness is obtained by measuring height variations in the surface profile. Statistical roughness parameters of nanofibrous mats are also obtained from direct measurement with roughness profilometry and atomic force microscopy (AFM) for comparison of the roughness of nanofibrous mats between direct measurement... 

A novel technique based on image processing inspired by the simple assumption for the first time to assess the roughness of nanofibrous mats based on grayscale variations is proposed. The height of a nanofibrous mat in different regions of the surface is simulated by grayscale variations in the image while the relation between grayscale and height is obtained as a linear function. The roughness is obtained by measuring height variations in the surface profile. Statistical roughness parameters of nanofibrous mats are also obtained from direct measurement with roughness profilometry and atomic force microscopy (AFM) for comparison of the roughness of nanofibrous mats between direct measurement... 

In the present work, a simple, green, rapid, and catalyst-free procedure for the synthesis of benzamide derivatives by ring opening of azlactones with diamines such as ethylene diamine and 1,3-propylenediamine is described. The present method offers several advantages such as short reaction times, easy work-up, and mild reaction conditions in the absence of catalyst and any toxic solvent and material. In addition, the structure obtained by X-ray crystallography was compared with the theoretical results obtained by density functional theory using the B3LYP functional and cc-pVDZ basis sets  

A novel technique based on image processing inspired by the simple assumption for the first time to assess the roughness of nanofibrous mats based on grayscale variations is proposed. The height of a nanofibrous mat in different regions of the surface is simulated by grayscale variations in the image while the relation between grayscale and height is obtained as a linear function. The roughness is obtained by measuring height variations in the surface profile. Statistical roughness parameters of nanofibrous mats are also obtained from direct measurement with roughness profilometry and atomic force microscopy (AFM) for comparison of the roughness of nanofibrous mats between direct measurement... 

An attempt was made to combine μ-solid phase extraction and headspace single drop microextraction techniques and use their advantages for trace determination of some volatile organic compounds in aqueous samples. After performing the two-step preconcentration approach, the desired analytes were determined by gas chromatography-mass spectrometry. A resorcinol-formaldehyde-based xerogel was used as the extraction medium in the μ-solid phase extraction (μ-SPE) method. Then, the extracted BTEX was eluted with a rather large amount of methanol. To remove the laborious process including solvent evaporation and further reconstitution, which is usually accompanied by loss of analytes and accuracy,... 

Comparative studies between response surface methodology (RSM) and artificial neural network (ANN) methods to find the effects of electrospinning parameters on the porosity of nanofiber mats is described. The four important electrospinning parameters studied included solution concentration (wt.%), applied voltage (kV), spinning distance (cm) and volume flow rate (mL/h). It was found that the applied voltage and solution concentration are the two critical parameters affecting the porosity of the nanofiber mats. The two approaches were compared for their modeling and optimization capabilities with the modeling capability of RSM showing superiority over ANN, having comparatively lower values of... 

This paper presents a new method to counter Anti Radiation Missile (ARM) threats, which is effective against advanced ARM. By using random phase and amplitude active decoys in the specified optimum positions and network implementation we show that ARM threats will be removed profoundly. Also, iterative methods are presented to cancel the internal interference effects in the proposed structure  

In this work we introduce new model for energy-delay product and the performance of 80-nm SOI-CMOS circuits for the range of Vdd=0.1-1.5V and Vth=0-0.8V, are analyzed to find optimal Vdd and Vth BSIMSOI3.3 model (level 57) is used to verify the answers. We show that Energy-Delay Product (EDP) isn't appropriate metric for gate sizing problem. And a new design metric is introduced as a generalization of EDP. This metric is used to determine the transistor sizing for complex circuits based on the specified delay and energy constrains. In this case, unlike the conventional energy delay product metric, delay and energy can be considered with different emphasis. The complete design flowcharts and... 

Background: Current development of sequencing technologies is towards generating longer and noisier reads. Evidently, accurate alignment of these reads play an important role in any downstream analysis. Similarly, reducing the overall cost of sequencing is related to the time consumption of the aligner. The tradeoff between accuracy and speed is the main challenge in designing long read aligners. Results: We propose Meta-aligner which aligns long and very long reads to the reference genome very efficiently and accurately. Meta-aligner incorporates available short/long aligners as subcomponents and uses statistics from the reference genome to increase the performance. Meta-aligner estimates... 

The novel coumarin-3-carboxamides (=2-oxo-2H-1-benzopyran-3-carboxamides) 5a-5g containing lipophilic spacers were synthesized through the Ugi-four-component reaction (Scheme 1). The reactions of aromatic aldehydes 1, 4,4'-oxybis[benzenamine] or 4,4'-methylenebis[benzenamine] as diamine 2, coumarin-3-carboxylic acid (=2-oxo-2H-benzopyran-3-carboxylic acid; 3), and alkyl isocyanides 4 lead to the desired substituted coumarin-3-carboxamides 5a-5g at room temperature with high bond-forming efficiency. These novel coumarin derivatives exhibit brilliant fluorescence at 544 nm in CHCl 3