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Estimation of jet grouting parameters in Shahriar dam,Iran

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Mining Science and Technology 2010年第3期20卷 472-477页

作者： NIkBAkHTAN B ahangari k RAHMANI N Department of Mining Engineering Science & Research BranchIslamic Azad UniversityTehran ***Iran Sahand University of Technology Tabriz ***Iran

Jet grouting is a method for improving of soil and its physical ***,in this method,grouting of cement slurry with high pressure and velocity may cause damaging to soil structure,and then excavated grains of soil are removed from the borehole and replaced with cement *** grains,which are remained around the borehole,mixed with slurry（cement） in-situ,can create an improved mass of *** mass is named＂Soilcrete＂.Soilcrete mass has special characteristics such as high strength,low deformability and very low *** this paper,principles of jet grouting and effective parameters have been *** the test results obtained from Soilcrete column have been ***,the paper concludes with presenting amount of principle jet grouting parameters at foundation of Shahriar dam according to the results of jet grouting *** on the measurements,the diameter,Soilcrete UCS（uniaxial compression strength）,amount of the water,grout and air pressure and lifting and rotating speed in original site of jet grouting are 1.2～1.5 m,2～3 MPa,370～390 bar,10～15 bar,6～8 bar,7～8 cm/min and 7～8 cm/min,*** it can be seen that while the column diameter falls within the upper half of the range,some values of the compressive strength are close to the lower limit of the range.

关键词： jet grouting ground improvement Soilcrete column Shahriar dam

Validation of Hoek-Brown failure criterion charts for rock slopes

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International Journal of Mining Science and Technology 2013年第6期23卷 805-808页

作者： A.M.Nekouei k.ahangari Department of Mining Engineering.Science and Research Branch Islamic Azad University

Although stability charts suggested by Hoek and Bray on the basis of Mohr-Coulomb criterion are used for rock slopes,but complete and precise recognition is required for distinguishing cohesive strength and Mohr-Coulomb equivalent internal friction angle for rock *** paper by Lia et al.[6]is the only one that introduced rock slope charts according to Hoek-Brown failure *** this paper,at first,this type of charts is ***,Mohr-Coulomb failure criterion charts[2]are compared and validated with Hoek-Brown failure criterion ones[6].Next,Bishop method utilizing Slide software is compared with Hoek-Brown failure criterion stability *** standard deviation(ASD),root mean square error(RMSE)and variance account for(VAF)were used for the *** to the results,because of high distribution and very low correlation among the comparisons,Hoek-Brown failure criterion charts are not efficient.

关键词： Slope stability Stability charts Mohr-Coulomb failure criterion Hoek-Brown failure criterion

Settlement modeling in central core rockfill dams by new approaches

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International Journal of Mining Science and Technology 2016年第4期26卷 703-710页

作者： Behnia D. ahangari k. Goshtasbi k. Moeinossadat S.R. Behnia M. Department of Mining Engineering Science and Research BranchIslamic Azad University Department of Mining Engineering Tarbiat Modares UniversityFaculty of Engineering Department of Civil Engineering Qaemshahr BranchIslamic Azad University

One of the most important reasons for the serious damage of embankment dams is their impermissible ***,it can be stated that the prediction of settlement of a dam is of paramount *** study aims to apply intelligent methods to predict settlement after constructing central core rockfill *** were made in this research to prepare models for predicting settlement of these dams using the information of 35 different central core rockfill dams all over the world and Adaptive Neuro-Fuzzy Interface System(ANFIS) and Gene Expression Programming(GEP) *** such as height of dam(H) and compressibility index(Ci) were considered as the input ***,a form was designed using visual basic software for predicting dam *** respect to the accuracy of the results obtained from the intelligent methods,they can be recommended for predicting settlement after constructing central core rockfill dams for the future plans.

关键词： Settlement Adaptive Neuro-Fuzzy Interface System(ANFIS)Gene Expression Programming (GEP)Visual Basic (VB)

Exhaustive Classification of the Invariant Solutions for a Specific Nonlinear Model Describing Near Planar and Marginally Long-Wave Unstable Interfaces for Phase Transition

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Communications in Theoretical Physics 2018年第5期69卷 477-505页

作者： Fatemeh ahangari Department of Mathematics Faculty of Mathematical SciencesAlzahra University

Problems of thermodynamic phase transition originate inherently in solidification, combustion and various other significant fields. If the transition region among two locally stable phases is adequately narrow, the dynamics can be modeled by an interface motion. This paper is devoted to exhaustive analysis of the invariant solutions for a modified kuramoto-Sivashinsky equation in two spatial and one temporal dimensions is presented. This nonlinear partial differential equation asymptotically characterizes near planar interfaces, which are marginally long-wave unstable. For this purpose, by applying the classical symmetry method for this model the classical symmetry operators are ***, the structure of the Lie algebra of symmetries is discussed and the optimal system of subalgebras, which yields the preliminary classification of group invariant solutions is constructed. Mainly, the Lie invariants corresponding to the infinitesimal symmetry generators as well as associated similarity reduced equations are also pointed out. Furthermore,the nonclassical symmetries of this nonlinear PDE are also comprehensively investigated.

关键词： phase transition modified kuramoto-Sivashinsky ((2D) MkS) equation symmetries optimal system invariant solutions

Tight-binding study of quantum transport in nanoscale GaAs Schottky MOSFET

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Chinese Physics B 2013年第9期22卷 634-639页

作者： Zahra ahangari Morteza Fathipour Department of Electrical Engineering Science and Research BranchIslamic Azad University School of Electrical and Computer Engineering University of Tehran

This paper explores the band structure effect to elucidate the feasibility of an ultra-scaled GaAs Schottky MOSFET （SBFET） in a nanoscale regime. We have employed a 20-band sp3dSs＊ tight-binding （TB） approach to compute E - k dis- persion. The considerable difference between the extracted effective masses from the TB approach and bulk values implies that quantum confinement affects the device performance. Beside high injection velocity, the ultra-scaled GaAs SBFET suffers from a low conduction band DOS in the F valley that results in serious degradation of the gate capacitance. Quan- tum confinement also results in an increment of the effective Schottky barrier height （SBH）. Enhanced Schottky barriers form a double barrier potential well along the channel that leads to resonant tunneling and alters the normal operation of the SBFET. Major factors that may lead to resonant tunneling are investigated. Resonant tunneling occurs at low temperatures and low drain voltages, and gradually diminishes as the channel thickness and the gate length scale down. Accordingly, the GaAs （100） SBFET has poor ballistic performance in nanoscale regime.

关键词： band structure quantum confinement effects resonant tunneling Schottky MOSFET

Symmetry Analysis and Conservation Laws for the Hunter-Saxton Equation

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Communications in Theoretical Physics 2013年第3期59卷 335-348页

作者： Mehdi Nadjafikhah Fatemeh ahangari School of Mathematics Iran University of Science and Technology

In this paper, the problem of determining the most general Lie point symmetries group and conservation laws of a well known nonlinear hyperbolic PDE in mathematical physics called the Hunter-Saxton equation （HSE） is anaiyzed. By applying the basic Lie symmetry method for the HSE, the classical Lie point symmetry operators are obtained. Also, the algebraic structure of the Lie algebra of symmetries is discussed and an optimal system of one- dimensional subalgebras of the HSE symmetry algebra which creates the preliminary classification of group invariant solutions is constructed. Particularly, the Lie invariants as well as similarity reduced equations corresponding to in- finitesimal symmetries are obtained. Mainly, the conservation laws of the HSE are computed via three different methods including Boyer＇s generalization of Noether＇s theorem, first homotopy method and second homotopy method.

关键词： Hunter-Saxton equation (HSE) Lie symmetry method invariant solution conservation laws Boyer's generalization of Noether's theorem Homotopy operator methods

Improved double-gate armchair silicene nanoribbon field-effect-transistor at large transport bandgap

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Chinese Physics B 2016年第1期25卷 809-816页

作者： Mohsen Mahmoudi Zahra ahangari Morteza Fathipour Department of Electrical and Computer Engineering University of Tehran Young Researchers and Elite Club Yadegar-e-Imam Khomeini (RAH) Shahre-Rey Branch Islamic Azad University

The electrical characteristics of a double-gate armchair silicene nanoribbon field-effect-transistor （DG ASiNR FET） are thoroughly investigated by using a ballistic quantum transport model based on non-equilibrium Green＇s function （NEGF） approach self-consistently coupled with a three-dimensional （3D） Poisson equation. We evaluate the influence of variation in uniaxial tensile strain, ribbon temperature and oxide thickness on the on-off current ratio, subthreshold swing, transconductance and the delay time of a 12-nm-length ultranarrow ASiNR FET. A novel two-parameter strain mag- nitude and temperature-dependent model is presented for designing an optimized device possessing balanced amelioration of all the electrical parameters. We demonstrate that employing HfO2 as the gate insulator can be a favorable choice and simultaneous use of it with proper combination of temperature and strain magnitude can achieve better device performance. Furthermore, a general model power （GMP） is derived which explicitly provides the electron effective mass as a function of the bandgap of a hydrogen passivated ASiNR under strain.

关键词： silicene double-gate field-effect-transistor non-equilibrium Green's function tight binding

Symmetry Reduction of Two-Dimensional Damped kuramoto-Sivashinsky Equation

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Communications in Theoretical Physics 2011年第8期56卷 211-217页

作者： Mehdi Nadjafikhah Fatemeh ahangari School of Mathematics Iran University of Science and Technology

In this paper, the problem of determining the largest possible set of symmetries for an important nonlinear dynamical system： the two-dimensional damped kuramoto-Sivashinsky （（21）） DkS ） equation is studied. By applying the basic Lie symmetry method for the （217）） DkS equation, the classical Lie point symmetry operators are obtained. Also, the optimal system of one-dimensional subalgebras of the equation is constructed. The Lie invariants as well as similarity reduced equations corresponding to infinitesimal symmetries are obtained. The nonclassicaJ symmetries of the （2D） DkS equation are also investigated.

关键词： two-dimensional damped kuramoto-Sivashinsky equation symmetry optimal system similaritysolutions

Calculation of maximum surface settlement induced by EPB shield tunnelling and introducing most effective parameter

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Journal of Central South University 2016年第12期23卷 3273-3283页

作者： Sayed Rahim Moeinossadat kaveh ahangari kourosh Shahriar Department of Mining Engineering Science and Research Branch Islamic Azad University Tehran Iran Department of Mining and Metallurgical Engineering Amirkabir University of Technology Tehran Iran

This study aims to predict ground surface settlement due to shallow tunneling and introduce the most affecting parameters on this *** on data collected from Shanghai LRT Line 2 project undertaken by TBM-EPB method,this research has considered the tunnel's geometric,strength,and operational factors as the dependent *** first,multiple regression(MR) method was used to propose equations based on various *** results indicated the dependency of surface settlement on many parameters so that the interactions among different parameters make it impossible to use MR method as it leads to equations of poor *** such,adaptive neuro-fuzzy inference system(ANFIS),was used to evaluate its capabilities in terms of predicting surface *** generated ANFIS models,the model with all input parameters considered produced the best prediction,so as its associated R^2 in the test phase was obtained to be *** equations and models in which operational factors were taken into consideration gave better prediction results indicating larger relative effect of such *** sensitivity analysis of ANFIS model,cosine amplitude method(CAM) was employed; among other dependent variables,fill factor of grouting(n) and grouting pressure(P) were identified as the most affecting parameters.

关键词： surface settlement shallow tunnel tunnel boring machine (TBM) multiple regression (MR) adaptive neuro-fuzzyinference system (ANFIS) cosine amplitude method (CAM)