Sharif Digital Repository

Ultrafiltration (UF) membranes were prepared from blends of poly(vinylidene fluoride) (PVDF)/polyacrylonitrile (PAN) via phase inversion method induced by immersion precipitation. Polyvinylpyrrolidone (PVP) was used as pore former and hydrophilic polymeric additive. N,N-dimethylacetamide (DMAc) and water were used as solvent and coagulant (non-solvent), respectively. The effect of different concentrations of PVP on the morphology and performance of the prepared membranes was investigated. Performance of the membranes was evaluated based on pure water flux and filtration of buffered bovine serum albumin (BSA) solution. The contact angle measurements indicated that the hydrophilicity of... 

In this study a more precise formulation of electrical capacitance for a cylindrical capacitive sensor is reported. By using different theoretical models such as Coulomb law, Gauss law and Laplace equation the electrical capacitance is calculated. Based on the given models the relation between the capacitance and the geometrical parameters (e.g., cylindrical length) is formulated and by using suitable software capacitance variation is computed and compared for different methods. In Coulomb method, the electrical potential is first solved numerically by using Mathematica and then the electrical capacitance is computed. It is found that the active capacitor length is crucial parameter in the... 

Ground reaction force (GRF) characteristics of amputee walking are important for the analysis of clinical gait data, and also to update model reference adaptive impedance (MRAI) controllers. GRF estimation is a better alternative than direct GRF measurement because of the disadvantages of load cells, such as high cost, integration difficulties due to weight and physical dimensions, the possibility of overload, and measurement noise. This paper presents four robust MRAI observer/controller combinations for GRF estimation-based control of a prosthesis and a legged robot model in the presence of parametric uncertainties and unmodeled dynamics, in which the robot model is employed to mimic... 

Objective: To determine the motor-behavioral and neural correlates of putative functional common variants in the sodium-channel NaV1.8 encoding gene (SCN10A) in vivo in patients with multiple sclerosis (MS). Methods: We recruited 161 patients with relapsing-onset MS and 94 demographically comparable healthy participants. All patients with MS underwent structural MRI and clinical examinations (Expanded Disability Status Scale [EDSS] and Multiple Sclerosis Functional Composite [MSFC]). Whole-brain voxel-wise and cerebellar volumetry were performed to assess differences in regional brain volumes between genotype groups. Resting-state fMRI was acquired from 62 patients with MS to evaluate... 

In this letter, we introduce a decentralized compute-and-forward (DCMF) protocol to solve the rank failure problem in compute-and-forward (CMF) ad hoc multi-user multi-relay networks without a central coordinator. In sufficiently strong inter-relay links, we show that the DCMF scheme can reach the same achievable rate as in the successive centralized CMF (SCCMF), which is a modified version of the previously introduced centralized CMF in using our proposed successive method for a fair comparison. We evaluate the outage probability and rate of the proposed strategy, and compare the results with those of the conventional CMF and decode-and-forward, and the SCCMF  

In this paper, we propose a scheme referred to as integer-forcing message recovering (IFMR) to enable receivers to recover their desirable messages in interference channels. Compared to the state-of-the-art integer-forcing linear receiver (IFLR), our proposed IFMR approach needs to decode considerably less number of messages. In our method, each receiver recovers independent linear integer combinations of the desirable messages each from two independent equations. We propose an efficient polynomial-time algorithm to sequentially find the equations and integer combinations with maximum rates and analyze its complexity. We evaluate the performance of our scheme and compare the results with the... 

This paper develops a stochastic geometry-based approach for the modeling and analysis of single- and multi-cluster wireless networks. We first define finite homogeneous Poisson point processes to model the number and locations of the transmitters in a confined region as a single-cluster wireless network. We study the coverage probability for a reference receiver for two strategies; closest-selection, where the receiver is served by the closest transmitter among all transmitters, and uniform-selection, where the serving transmitter is selected randomly with uniform distribution. Second, using Matern cluster processes, we extend our model and analysis to multi-cluster wireless networks. Here,... 

This paper develops a tractable modeling and analysis framework for finite cellular wireless networks using stochastic geometry. Defining finite homogeneous Poisson point processes to model the number and locations of access points in a confined region, we study the coverage probability for an arbitrarily-located reference user that is served by the closest access point. The distance distribution and the Laplace transform (LT) of the interference are derived. We also derive a closed-form lower bound on the LT of the interference. Our analyses reveal that a higher path loss exponent improves the coverage probability and that there is a location where the coverage probability is maximized. ©... 

Usage of masonry system in many regions of the world like the Eastern Mediterranean, the Middle East, India, and China is still significantly high, despite their highly energy and intensive emission. Most of the failures in this system are caused by low ductility of cement mortars. This type of failure could be seen in masonry structures in areas in east Iran after Kermanshah earthquake in 2017. The present study investigates the shear bond characteristics of structures constructed by masonry using green materials. “Taftan” natural pozzolan and two types of rice husk ash (RHA) were used in mix design of used mortars as green materials. In this investigation, a modified direct shear test... 

Aim: SHARIF-HMIS is a new inertial sensor designed for movement analysis. The aim of the present study was to assess the inter-tester and intra-tester reliability of some kinematic parameters in different lumbar motions making use of this sensor. Materials and methods: 24 healthy persons and 28 patients with low back pain participated in the current reliability study. The test was performed in five different lumbar motions consisting of lumbar flexion in 0, 15, and 30° in the right and left directions. For measuring inter-tester reliability, all the tests were carried out twice on the same day separately by two physiotherapists. Intra-tester reliability was assessed by reproducing the tests... 

ARX algorithms are a class of symmetric-key algorithms constructed by Addition, Rotation, and XOR. To evaluate the resistance of an ARX cipher against differential and impossible-differential cryptanalysis, the recent automated methods employ constraint satisfaction solvers to search for optimal characteristics or impossible differentials. The main difficulty in formulating this search is finding the differential models of the non-linear operations. While an efficient bit-vector differential model was obtained for the modular addition with two variable inputs, no differential model for the modular addition by a constant has been proposed so far, preventing ARX ciphers including this...