Dynamic instability response in nanocomposite pipes conveying pulsating ferrofluid flow considering structural damping effects

Esmaeili, Hemat Ali,Khaki, Mehran,Abbasi, Morteza Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.68 No.3

This paper deals with the dynamic stability of nanocomposite pipes conveying pulsating ferrofluid. The pipe is reinforced by carbon nanotubes (CNTs) where the agglomeration of CNTs are considered based on Mori-Tanaka model. Due to the existence of CNTs and ferrofluid flow, the structure and fluid are subjected to axial magnetic field. Based on Navier-Stokes equation and considering the body forced induced by magnetic field, the external force of fluid to the pipe is derived. For mathematical modeling of the pipe, the first order shear deformation theory (FSDT) is used where the energy method and Hamilton's principle are used for obtaining the motion equations. Using harmonic differential quadrature method (HDQM) and Bolotin's method, the motion equations are solved for calculating the excitation frequency and dynamic instability region (DIR) of the structure. The influences of different parameters such as volume fraction and agglomeration of CNTs, magnetic field, structural damping, viscoelastic medium, fluid velocity and boundary conditions are shown on the DIR of the structure. Results show that with considering agglomeration of CNTs, the DIR shifts to the lower excitation frequencies. In addition, the DIR of the structure will be happened at higher excitation frequencies with increasing the magnetic field.

Broken Toughness: Iranian Older Adults’ Perceptions of Abuse

Esmaeili Maryam,Adib Masoomeh,Zakeri Moghadam Masomeh,Dehghan Nayeri Nahid,Mazaheri Monireh 대한노인병학회 2022 Annals of geriatric medicine and research Vol.26 No.3

Background: Older people abuse includes intentional or unintentional conduct or omission of a specific behavior by a trusted person that causes injury or distress to older people. This study described older peoples’ perceptions of abuse in Iranian society. Methods: This qualitative study applied a conventional content analysis method to understand the perceptions of abuse among older Iranian people. Twenty older residents were selected by purposeful sampling. Data were collected through in-depth, semi-structured, and face-to-face interviews. The six-step Graneheim and Lundman content analysis method guided data analysis. MAXQDA software version 10 was used to manage the data. Results: The data analysis led to the identification of three main themes: broken toughness, hidden abuse, and exploitation. The first theme had two sub-themes: domination and disturbed peace and tranquility. Conclusion: Abuse resulted from a combination of causes and factors. Abuse was hidden in many cases and was not limited to physical abuse. The other examples of abuse included disrespect, deprivation of authority, disturbed tranquility, and financial exploitation of older adults.

Dynamic stability of nanocomposite Mindlin pipes conveying pulsating fluid flow subjected to magnetic field

Esmaeili, Hemat Ali,Khaki, Mehran,Abbasi, Morteza Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.67 No.1

In this work, the dynamic stability of carbon nanotubes (CNTs) reinforced composite pipes conveying pulsating fluid flow is investigated. The pipe is surrounded by viscoelastic medium containing spring, shear and damper coefficients. Due to the existence of CNTs, the pipe is subjected to a 2D magnetic field. The radial induced force by pulsating fluid is obtained by the Navier-Stokes equation. The equivalent characteristics of the nanocomposite structure are calculated using Mori-Tanaka model. Based on first order shear deformation theory (FSDT) or Mindlin theory, energy method and Hamilton's principle, the motion equations are derived. Using harmonic differential quadrature method (HDQM) in conjunction with the Bolotin's method, the dynamic instability region (DIR) of the system is calculated. The effects of different parameters such as volume fraction of CNTs, magnetic field, boundary conditions, fluid velocity and geometrical parameters of pipe are shown on the DIR of the structure. Results show that with increasing volume fraction of CNTs, the DIR shifts to the higher frequency. In addition, the DIR of the structure will be happened at lower excitation frequencies with increasing the fluid velocity.

Activated carbon@MgO@Fe3O4 as an efficient adsorbent for As (III) removal

Esmaeili Hossein,Mousavi Seyyed Mojtaba,Hashemi Seyyed Alireza,Chiang Wei-Hung,Ahmadpour Abnavi Somayeh 한국탄소학회 2021 Carbon Letters Vol.31 No.5

In this study, Fe3O4/MgO/Activated carbon composite was used to remove arsenic ion (As (III)) from aqueous media. To this end, Frangula Alnus was used to prepare activated carbon (AC) by calcination in the furnace at 700 °C for 4 h and was then used to synthesize the MgO/Fe3O4/AC composite. To study the surface properties of the composite, various analyses such as SEM, EDX/Mapping, FTIR, DLS, BET and VSM were applied. According to the BET analysis, the specifc surface area and average pore size of the Fe3O4/MgO/AC composite were obtained as 190.92 m2 /g and 7.57 nm, respectively, which showed that the aforementioned nanocomposite had a mesoporos structure with an excellent specifc surface area. Also, VSM analysis indicated that the composite had a superparamagnetic property and could be easily separated from the solution by a magnet. Moreover, the results of the As (III) sorption indicated that the highest uptake efciency was obtained 96.65% at pH=7, adsorbent dosage=0.13 g/L, t=35 min, T=45 °C and Co=6 mg/L. In addition, the pseudo-second-order model could better describe the kinetic behavior of the sorption process. Furthermore, Langmuir model was the best model to describe the equilibroium behavior of the As(III) ion sorption. Besides, according to the the thermodynamic study, enthalpy change and entropy change were obtained 58.11 kJ/mol and 224.49 J/mol.K, respectively, indicating that the sorption process was spontaneous and endothermic. According to the results, the Fe3O4/MgO/AC composite was a good adsorbent with the extraordinary properties, which can be used on an industrial scale.

Characterization, permeation analysis and stability increasing of facilitated transport membranes through incorporation of bis(bipyridine) silver (II) peroxydisulfate

M. Esmaeili,S.S. Madaeni,S. Attar Nosrati,A. Vahidi Ferdowsi,M. Joshagani 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.29 No.-

Bis(bipyridine) silver (II) peroxydisulfate (Ag(bipy)2S2O8) has been applied as an alternative salt in thepreparation of polyethersulfone (PES)/polyethylene oxide (PEO) facilitated transport membranes aimingat postponing the reduction process of silver carrier agents. The geometrical structure, mechanical andpermeation properties of membranes containing Ag(bipy)2S2O8 or AgBF4 salts were compared in theethylene/ethane separation process. Formation of silver nanoparticles from [Ag(bipy)2]2+ cations was lower than from Ag+, which wasdetected by means of UV–Visible spectroscopy and transmission electron microscopy (TEM). The twopositive charges of [Ag(bipy)2]2+ cations besides oxidative properties of S2O82 anions postponed thereduction time of active sites. Ag(bipy)2S2O8 incorporated membranes possessed higher permeation,selectivity durability, mechanical strength and stronger CO bond strength and lower pore size andsurface roughness than that of membranes containing AgBF4 salt. Lower lattice energy and sterichindrance of AgBF4 salt resulted in homogeneous distribution of Ag+ cations and counter-ions. Themaximum selectivity of 124 was obtained at the highest AgBF4 concentration (molar percent = 50%) andoperational pressure (4 barg). On the other hand, the maximum ethylene selectivity after saturation stepbelonged to the membrane containing (Ag(bipy)2S2O8) salt, which was 115 at the same condition.

Performance analysis tool for reinforced concrete members

Asad Esmaeily,Robert J. Peterman 한국계산역학회 2007 Computers and Concrete, An International Journal Vol.4 No.5

A computer program was developed to analyze the non-linear, cyclic flexural performance of reinforced concrete structural members under various types of loading paths including non-sequential variations in axial load. This performance is significantly affected by the loading history. Different monotonic material models as well as hysteresis rules for confined and unconfined concrete and steel, some developed and calibrated against test results on material samples, were implemented in a fiber-based moment-curvature and in turn force-deflection analysis. One of the assumptions on curvature distribution along the member was based on a method developed to address the variation of the plastic hinge length as a result of loading pattern. Functionality of the program was verified by reproduction of analytical results obtained by others for several cases, and accuracy of the analytical process and the implemented models were evaluated against the experimental results from large-scale reinforced concrete columns tested under the analyzed loading cases. While the program can be used to predict the response of a member under a certain loading pattern, it can also be used to examine various analytical models and methods or refine a custom material model against test data.

Investigating the effect of clamping force on the fatigue life of bolted plates using volumetric approach

F. Esmaeili,T. N. Chakherlou,M. Zehsaz,S. Hasanifard 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.12

In this paper, the effects of bolt clamping force on the fatigue life for bolted plates made from Al7075-T6 have been studied on the values of notch strength reduction factor obtained by volumetric approach. To attain stress distribution around the notch (hole) which is required for volumetric approach, nonlinear finite element simulations were carried out. To estimate the fatigue life, the available smooth S-N curve of Al7075-T6 and the notch strength reduction factor obtained from volumetric method were used. The estimated fatigue life was compared with the available experimental test results. The investigation shows that there is a good agreement between the life predicted by the volumetric approach and the experimental results for various specimens with different amount of clamping forces. Volumetric approach and experimental results showed that the fatigue life of bolted plates improves because of the compressive stresses created around the plate hole due to clamping force.

THE TOTAL TORSION ELEMENT GRAPH WITHOUT THE ZERO ELEMENT OF MODULES OVER COMMUTATIVE RINGS

Fatemeh Esmaeili Khalil Saraei 대한수학회 2014 대한수학회지 Vol.51 No.4

Let M be a module over a commutative ring R, and let T(M) be its set of torsion elements. The total torsion element graph of M over R is the graph T(Γ(M)) with vertices all elements of M, and two distinct vertices m and n are adjacent if and only if m + n ∈ T(M). In this paper, we study the basic properties and possible structures of two (induced) subgraphs Tσr0 (Γ(M)) and T0 (Γ(M)) of T(Γ(M)), with vertices T(M) \ {0} and M \ {0}, respectively. The main purpose of this paper is to extend the definitions and some results given in [6] to a more general total torsion element graph case.

Sonochemical synthesis of HgSe nanoparticles: Effect of metal salt, reaction time and reductant agent

Mahdiyeh Esmaeili-Zare,Masoud Salavati-Niasari,Azam Sobhani 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

A convenient sonochemical process for the preparation of mercury selenide (HgSe) nanoparticles has been developed based on the reaction of mercury salt and SeCl4 in the presence of triethanolamine (TEA) as complexing agent and N2H4 H2O (hydrazine hydrate) as the reductant agent at room temperature. The effects of preparation parameters such as metal salt, reaction time, reductant agent and its quantity on the morphology, the particle size and the phase of the final products have been investigated. The products were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray powder diffraction (XRD).

Novel membrane reactor design for heavy-metal removal by alginate nanoparticles

Akbar Esmaeili,Ali Aghababai Beni 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.26 No.-

The membrane reactor was also employed in conjuncton with a membrane composed of Sargassum glaucescens brown algae nanoparticles to test its efficacy in removing nickel and cobalt from real effluents. Alginate nanoparticles with an average diameter of 95.75 nm and surface area of 11.25 m2 g1 were used. Maximum uptake capacities of Ni2+ and Co2+ were obtained at pH 6.0, optimum biosorption capacity of the alginate nanoparticles was found to be 90.25% for Ni2+ and 86.13% for Co2+. An artificial neural network was applied for the prediction of percentages of biosorption capacity