Sharif Digital Repository

An analytic expression for energy and angular dependence of a secondary charged lepton in the decay of a polarized top quark with anomalous tWb couplings in the presence of all anomalous couplings are derived. The angular distribution of the b-quark is derived as well. It is presented that the charged lepton spin correlation coefficient is not very sensitive to the anomalous couplings. However, the b-quark spin correlation coefficient is sensitive to anomalous couplings and could be used as a powerful tool in the search for non-SM coupling. © 2007 IOP Publishing Ltd  

In this paper we study the noncommutative effects to the lepton spectrum from the decay of a polarized top quark. It is shown that the lowest contribution comes from the quadratic terms of the noncommutative parameter. The deviations from the standard model are significant for small values of the noncommutative characteristic scale. However, the charged lepton spin correlation coefficient has a remarkable deviation from the standard model from very low values of the noncommutative characteristic scale to 1 TeV. © 2006 The American Physical Society  

In this article, two adaptive model predictive controllers (AMPC) are applied to regulate the blood glucose in type 1 diabetic patients. The first controller is constructed based on a linear model, while the second one is designed by using a nonlinear Hammerstein model. The adaptive version of these control schemes is considered to make them more robust against model mismatches and external disturbances. The least squares method with forgetting factor is used to update the model parameters. For simulation study, two well-known mathematical models namely, Puckett and Hovorka which describe the dynamical behavior of patient's body have been selected. The performances and robustness of the... 

The anomalous top quark interactions with gluon (tug, tcg) allow the production of single top quarks at the Large Hadron Collider (LHC). Using the angular distribution of the charged lepton from the W boson in the top decay, we show that with the data of 10 fb-1 of integrated luminosity and in the collisions with the center of mass energy of 14TeV, the anomalous up and charm quarks coupling parameters κu,c/Λ can be measured down to 0.005 and 0.007 TeV-1, respectively  

In this study, a novel type of passive energy dissipation device called a Telescopic Lead Yielding Damper (TLYD) is proposed and analyzed. This device comprises co-axial steel cylinders and lead rings, such that these rings act as shear locks between the steel cylinders. TLYDs dissipate energy through the plastic shear deformation of lead metal. The telescopic mechanism used in TLYDs allows these small-sized dampers to tolerate large axial displacements with low fatigue. For each telescopic level, a yield plateau is added to the hysteresis behavior of TLYD devices. Each yield plateau resists a different performance level, namely design-based and maximum credible earthquakes. Seven... 

This work introduces a new gradient fiber coating for microextraction of chlorobenzenes. Nanoclusters of organoclay-Cu(II) on a copper wire were fabricated by wireless electrofunctionalization. The resultant gradient coatings are more robust, and thermally and mechanically stable. Wireless electrofunctionalization was carried out in a bipolar cell under a constant deposition potential and using an ethanolic electrolyte solution containing stearic acid and montmorillonite. Stearic acid acts as an inexpensive and green coating while montmorillonite acts as a modifier to impart thermal stability. The gradient morphology of the nanoclusters was investigated by scanning electron microscopy,... 

Microalgae have been remarkably taken into account due to their wide applications in the biopharmaceutical, nutraceutical and bio-energy fields. However, contamination of microalgae with bacteria still appears to be a concern, adversely impacting products’ quality and process efficiency. Microalgae decontamination with conventional techniques is usually expensive and time-consuming. Moreover, damage to microalgae cells is highly possible. Asymmetric contraction-expansion microchannels (Asym-CEMCs) are promising passive microfluidic devices that can overcome conventional techniques' drawbacks with their standing-out features. However, the flexibility of Asym-CEMCs performance arising from... 

The gas chromatography retention indices of 100 different components of essential oils, on three columns with stationary phases of different polarities, were used to develop robust quantitative structure-retention relationship (QSRR) models. Two linear models with only one variable, i.e. solvation entropy, were developed, which explain 95 and 94% of variances of the test set for dimethyl silicone and dimethyl silicone with 5% phenyl group columns, respectively. These models are extremely simple and easy to interpret, but they show higher errors compared with more robust models such as partial least square (PLS) and ridge regressions. For the third column (polyethylene glycol (PEG)), 24... 

This contribution focuses on the use of ladder particle swarm optimisation (LPSO) on modelling of oxadiazole- and triazolesubstituted naphthyridines as human immunodeficiency virus-1 integrase inhibitors. Artificial neural network (ANN) and Monte Carlo cross-validation techniques were combined with LPSO to develop a quantitative structure-activity relationship model. The techniques of LPSO, ANN and sample set partitioning based on joint x-y distances were applied as feature selection, mapping and model evaluation, respectively. The variables selected by LPSO were used as inputs of Bayesian regularisation ANN. The statistical parameters of correlation of deterministic, R2, and... 

In this paper, an analytical performance model for adaptive wormhole routing in the hypercube-based optical transpose interconnection system (OTIS-hypercube) is proposed and validated. Using this model, the performance merits of the OTIS-hypercube are discussed. We also compare the performance of the OTIS-hypercube with that of equivalent hypercube network under different implementation constraints. Compared to pure simulation results, the presented model can serve as a more appropriate and compact method to display the performance characteristics of OTIS-hypercube networks. © 2007 Elsevier Inc. All rights reserved  

In this study, the local composition based models such as the Wilson, the nonrandom two-liquid (NRTL), and the Wilson-NRF have been applied in correlation and estimation of density, viscosity, and surface tension of biodiesels. The thermodynamic models have been used in correlating the thermophysical properties for 215 experimental data points. These models have the interaction energy between each pair that is considered as adjustable parameters. To decrease the number of these adjustable parameters, it is assumed that the biodiesels are composed of two hypothetical components. The average absolute deviation (AADs) of the correlated density of biodiesels for the Wilson, the NRTL, and the... 

A significant portion of Iranian flat breads are produced in semi-industrial, indirect-heating ovens. Therefore, an efficient oven design and a proper selection of operating conditions are crucial to improve the product quality and reduce energy consumption. In the present study, a mathematical model is developed to simulate a semi-industrial, indirect-heating, continuous oven performance during contact baking of an Iranian flat bread, referred to as Taftoon. Individual modes of heat transfer are considered among various components of the baking system to estimate the system performance and the bread quality in terms of design and operating conditions. The predictions of this model are in... 

In this research, direct conversion of wet algal biomass into biodiesel using supercritical methanol was studied. In this process, microalgal lipids simultaneously was extracted and converted to biodiesel under high pressure and temperature conditions without using any catalyst. Several experiments have been performed to optimize the methanol amount and it has been revealed that the best performance was achieved by using methanol/wet biomass ratio of 8:1. The effect of using various co-solvents in increasing the efficiency of the supercritical process was investigated. It has been shown that hexane was the most effective co-solvent and its optimal ratio respect to wet biomass was 6:1. The... 

The extraction and purification of lipids from the microalgae Chlorella vulgaris have been investigated. First, a mixture of hexane and ethanol was used to extract lipids from the algal biomass. Ultrasonication was employed to disrupt the cell wall and increase the extraction performance. Under these conditions, over 90% of the fatty acids in the biomass were extracted. Second, a biphasic system was formed by adding water and hexane to the extracted crude oil. In this way, fatty acids were mainly distributed in the organic phase (mostly hexane and ethanol) while most of the contaminants remained in the aqueous phase (mostly water and ethanol). Equilibrium distribution data between the phases... 

The aim of this study is to introduce an extractive phase based on gradient concept by continuous changing in chemical functional groups for non–targeted analysis. For this purpose, three different two–component coatings containing (3–aminopropyl)trimethoxysilane (APTES) as polar and either phenyltriethoxysilane (PTES), octyl–trimethoxysilane (OTMS) or methyltrimethoxysilane (MTMS) as nonpolar precursors were formed on the modified stainless steel wires using controlled rate infusion (CRI) method. The presence of polar and/or non–polar functional groups on the surface of substrate was evaluated by Fourier–transform infrared spectroscopy (FTIR) together with contact angles determined... 

To help walking, using assistive devices can be considered to reduce the loads caused by weight and to effectively decrease the propulsive forces. In this study, a mobility Saddle-Assistive Device (S-AD) supporting body weight while walking was evaluated on two healthy volunteers. This device is based on the support of body weight against gravity with the help of a saddle, which is not used in other passive mobility assistive devices. To prove the efficiency of this device, the experimental results obtained while walking with this device were compared with those related to walking without the assistive device. The results showed that this device could significantly reduce the forces and... 

A gradient derived base layer extractive phase was synthesized and applied for the determination of volatile organic compounds (VOCs) in saliva samples using the headspace cooled in–tube microextraction (HS–CITME) method. The base layers from three different sols of phenyltriethoxysilane (PTES), octyltrimethoxysilane (OTMS) and methyltrimethoxysilane (MTMS) as nonpolar precursors were individually dip coated on the stainless steel wires (SSW). Then, the hydrolyzed polar precursor aminopropyltriethoxysilane (APTES) reacted with the silanol groups already formed on the surface of SSWs via controlled rate infusion (CRI) method. The presence of polar and non–polar functional groups on the...