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CONTENTS
Volume 12, Number 1, January 2022
 

Abstract
To date, nondestructive tests (NDT) applications and advances in detecting the dispersion and defections of the nano concrete (NC) materials fields are very limited. The current paper provides a review of the dispersion efficiency of nanomaterials in cement-based materials and how NDT can be efficiently used in detecting and visualizing the defections and dispersions of NC. The review identifies the characteristics of different types of nanoparticles used in NC. Nanomaterials influences on concrete characteristics and their dispersion degree are presented and discussed. The main aim of this article is to present and compare the common NDT that can be used for detecting and visualizing the defections and dispersions of different kinds of nanomaterials utilized in NC. The different microscopy and X-ray methods are explicitly reviewed and compared. Based on the collected data, it can be concluded that the fully detecting and visualizing of NC defections and dispersions have not been fully discovered and that needs further investigations. So, the distinction of this paper lies in defining NDT that can be employed for detecting and/or visualizing NC defections and dispersions.

Key Words
defect detection and visualization; dispersion; microscopy; nondestructive tests; pulse-ultrasonic; X-ray

Address
Mosbeh R. Kaloop: Department of Civil and Environmental Engineering, Incheon National University, Incheon, Korea/ Incheon Disaster Prevention Research Center, Incheon National University, Incheon, Korea/ Public Works and Civil Engineering Department, Mansoura University, Mansoura, Egypt


Mohamed Abd Elrahman: Structural Engineering Department, Mansoura University, Mansoura, Egypt

Jong Wan Hu: Department of Civil and Environmental Engineering, Incheon National University, Incheon, Korea/ Incheon Disaster Prevention Research Center, Incheon National University, Incheon, Korea


Abstract
Within the framework of the density functional theory combined with the method of non-equilibrium Green's functions (DFT + NEGF), the features of electron transport in fullerene nanojunctions, which are "core-shell" nanoobjects made of a combination of fullerenes of different diameters C20, C80, C180, placed between gold electrodes (in a nanogap), are studied. Their transmission spectra, the density of state, current-voltage characteristics and differential conductivity are determined. It was shown that in the energy range of -0.45–0.45 eV in the transmission spectrum of the "Au–C180–Au" nanojunction appears a HOMO–LUMO gap with a width of 0.9 eV; when small-sized fullerenes C20, C80 are intercalation into the cavity C180 the gap disappears, and a series of resonant structures are observed on their spectra. It has been established that distinct Coulomb steps appear on the current-voltage characteristics of the "Au–C180–Au" nanojunction, but on the current-voltage characteristics "Au–C80@C180–Au", "Au–(C20@C80)@C180–Au" these step structures are blurred due to a decrease in Coulomb energy. An increase in the number of Coulomb features on the dI/dV spectra of core-shell fullerene nanojunctions was revealed in comparison with nanojunctions based on fullerene C60, which makes it possible to create high-speed single-electron devices on their basis. Models of single–electron transistors (SET) based on fullerene nanojunctions "Au–C180–Au", "Au–C80@C180–Au" and "Au–(C20@C80)@C180-Au" are considered. Their charge stability diagrams are analyzed and it is shown that SET based on C80@C180, (C20@C80)@C180 nanojunctions is output from the Coulomb blockade mode with the lowest drain-to-source voltage.

Key Words
Coulomb blockade; current-voltage characteristic; electron transport; fullerene; nanojunction, single–electron transistor

Address
Daulet Sergeyev: Department of Physics, K. Zhubanov Aktobe Regional State University, 34A Moldagulova avenue, 030000 Aktobe, Kazakhstan/ Department of Radio Electronics, T. Begeldinov Aktobe Aviation Institute, 39 Moldagulova avenue, 030012 Aktobe, Kazakhstan

Ainur Duisenova: Department of Physics, K. Zhubanov Aktobe Regional State University, 34A Moldagulova avenue, 030000 Aktobe, Kazakhstan

Abstract
In this paper, the non-linear static analysis of Timoshenko nanobeams consisting of bi-directional functionally graded material (BFGM) with immovable ends is investigated. The scratching in the FG nanobeam mid-plane, is the source of nonlinearity of the bending problems. The nonlocal theory is used to investigate the non-linear static deflection of nanobeam. In order to simplify the formulation, the problem formulas is derived according to the physical middle surface. The Hamilton principle is employed to determine governing partial differential equations as well as boundary conditions. Moreover, the differential quadrature method (DQM) and direct iterative method are applied to solve governing equations. Present results for non-linear static deflection were compared with previously published results in order to validate the present formulation. The impacts of the nonlocal factors, beam length and material property gradient on the non-linear static deflection of BFG nanobeams are investigated. It is observed that these parameters are vital in the value of the non-linear static deflection of the BFG nanobeam.

Key Words
Eringen's nonlocal theory; bi-directional functionally graded; nanobeam; non-linear static deflection; Timoshenko theory

Address
Mojtaba Gorji Azandariani: Structural Engineering Division, Faculty of Civil Engineering, Semnan University, Semnan, Iran

Mohammad Gholami: Department of Civil Engineering, Yasouj University, Yasouj, Iran

Akbar Nikzad: Department of Civil Engineering, Islamic Azad University of Bushehr, Bushehr, Iran

Abstract
Nanocatalysts are usually used in the synthesis of petrochemical products, fine chemicals, biofuel production, and automotive exhaust catalysis. Due to high activity and stability, recyclability, and cost-effectiveness, nanocatalysts are a key area in green chemistry. On the other hand, water as a common by-product or undesired element in a range of nanocatalyzed processes may be promoting the deactivation of catalytic systems. The advancement in the field of hydrophobicity in nanocatalysis could relatively solves these problems and improves the efficiency and recyclability of nanocatalysts. Some recent developments in the synthesis of novel nanocatalysts with tunable hydrophilic-hydrophobic character have been reviewed in this article and followed by highlighting their use in catalyzing several processes such as glycerolysis, Fenton, oxidation, reduction, ketalization, and hydrodesulfurization. Zeolites, carbon materials, modified silicas, surfactant-ligands, and polymers are the basic components in the controlling hydrophobicity of new nanocatalysts. Various characterization methods such as N2 adsorption-desorption, scanning and transmission electron microscopy, and contact angle measurement are critical in the understanding of hydrophobicity of materials. Also, in this review, it has been shown that how the hydrophobicity of nanocatalyst is affected by its structure, textural properties, and surface acidity, and discuss the important factors in designing catalysts with high efficiency and recyclability. It is useful for chemists and chemical engineers who are concerned with designing novel types of nanocatalysts with high activity and recyclability for environmentally friendly applications.

Key Words
carbon material; hydrophobicity; nanocatalyst; silica; zeolite

Address
Khadijeh Alimoradlu: Department of Nanotechnology, Faculty of Science, Urmia University, Urmia, Iran

Asghar Zamani: Nanotechnology Research Center, Urmia University, Urmia, Iran

Abstract
The dynamic properties (frequencies, mode shapes, damping ratios) of the scaled WPC warehouse are compared using the operational modal analysis approach to the dynamic parameters (frequencies, mode shapes, damping ratios) of the full outer surface of titanium dioxide, 70 micron in thickness. Micro tremor ambient vibration data on ground level was used to provide ambient excitation. For the output-only modal identification, Enhanced Frequency Domain Decomposition (EFDD) was used. This study discovered a strong correlation between mode shapes. Titanium dioxide applied to the entire outer surface of the scaled WPC warehouse results in an average 14.05 percent difference in frequency values and 7.61 percent difference in damping ratios, demonstrating that nanomaterials can be used to increase rigidity in structures, or for reinforcement. Another significant finding in the study was the highest level of adherence of titanium dioxide and similar nanomaterials mentioned in the introduction to WPC structure surfaces.

Key Words
EFDD; nanomaterial; operational modal analysis; TiO2; WPC

Address
Sertaç Tuhta: Ondokuz Mayis University, Faculty of Engineering, Department of Civil Engineering, Atakum/Samsun, Turkey

Abstract
Due to the extensive use of concrete structures in various applications, the improvement of their strength and quality has become of great importance. A new way of achieving this purpose is to add different types of nanoparticles to concrete admixtures. In this work, a mathematical model has been employed to analyze the vibration of concrete beams reinforced by graphene oxide (GO) nanoparticles. To verify the accuracy of the presented model, an experimental study has been conducted to compare the compressive strengths of these beams. Since GO nanoparticles are not readily dissolved in water, before producing the concrete samples, the GO nanoparticles are dispersed in the mixture by using a shaker, magnetic striker, ultrasonic devices, and finally, by means of a mechanical mixer. The sinusoidal shear deformation beam theory (SSDBT) is employed to model the concrete beams. The Mori-Tanaka model is used to determine the effective properties of the structure, including the agglomeration influences. The motion equations are calculated by applying the energy method and Hamilton's principle. The vibration frequencies of the concrete beam samples are obtained by an analytical method. Three samples containing 0.02% GO nanoparticles are made and their compressive strengths are measured and compared. There is a good agreement between our results and those of the mathematical model and other papers, with a maximum difference of 1.29% between them. The aim of this work is to investigate the effects of nanoparticle volume fraction and agglomeration and the influences of beam length and thickness on the vibration frequency of concrete structures. The results show that by adding the GO nanoparticles, the vibration frequency of the beams is increased.

Key Words
analytical method; concrete beam; experimental method; GO nanoparticles; vibration

Address
Reza Kasiri: Department of Civil Engineering, Khorasgan Branch, Islamic Azad University, Isfahan, Iran

Saeed Reza Massah: Department of Civil Engineering, Faculty of Civil Engineering, Iran University of Science and Technology, Tehran, Iran

Abstract
The aim of current work is to evaluate thermo-electrical characteristics of graphene nanoplatelets Reinforced Composite (GNPRC) coupled with magneto-electro-elastic (MEE) face sheet. In this regard, a cylindrical smart nanocomposite made of GNPRC with an external MEE layer is considered. The bonding between the layers are assumed to be perfect. Because of the layer nature of the structure, the material characteristics of the whole structure is regarded as graded. Both mechanical and thermal boundary conditions are applied to this structure. The main objective of this work is to determine critical temperature and critical voltage as a function of thermal condition, support type, GNP weight fraction, and MEE thickness. The governing equation of the multilayer nanocomposites cylindrical shell is derived. The generalized differential quadrature method (GDQM) is employed to numerically solve the differential equations. This method is integrated with Deep Learning Network (DNN) with ADADELTA optimizer to determine the critical conditions of the current sandwich structure. This the first time that effects of several conditions including surrounding temperature, MEE layer thickness, and pattern of the layers of the GNPRC is investigated on two main parameters critical temperature and critical voltage of the nanostructure. Furthermore, Maxwell equation is derived for modeling of the MEE. The outcome reveals that MEE layer, temperature change, GNP weight function, and GNP distribution patterns GNP weight function have significant influence on the critical temperature and voltage of cylindrical shell made from GNP nanocomposites core with MEE face sheet on outer of the shell.

Key Words
critical temperature; critical voltage; deep learning network; graphene nanoplatelets; neural network

Address
Xiao Zhou: College of science, Hubei University of Automotive Technology, Shiyan, 442002, Hubei, China

Pinyi Wang: Department of Electrical and Computer Engineering, University of Washington Seattle, WA 98195, USA

Mujahed Al-Dhaifallah: Control and Instrumentation Engineering Department, King Fahd University of Petroleum & Minerals, 31261 Dhahran, KSA/ Interdisciplinary Research Center (lRC) for Renewable Energy and Power Systems, King Fahd University of Petroleum & Minerals, 31261 Dhahran, KSA

Muhyaddin Rawa : Center of Research Excellence in Renewable Energy and Power Systems, King Abdulaziz University, Jeddah 21589, Saudi Arabia/ K. A. CARE Energy Research and Innovation Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia/ Department of Electrical and Computer Engineering, Faculty of Engineering, King Abdulaziz University, Jeddah 21589, Saudi Arabia

Mohamed Amine Khadimallah: Prince Sattam Bin Abdulaziz University, College of Engineering, Civil Engineering Department, Al-Kharj, 16273, Saudi Arabia/ Laboratory of Systems and Applied Mechanics, Polytechnic School of Tunisia, University of Carthage, Tunis, Tunisia


Abstract
Some researchers pointed out that the nonlocal cantilever models do not predict the dynamic softening behavior for nanostructures (including nanobeams) with clamped-free (CF) ends. In contrast, some indicate that the nonlocal cantilever models can capture the stiffness softening characteristics. There are substantial differences on this issue between them. The vibration analysis of porosity-dependent functionally graded nanoscale tubes with variable boundary conditions is investigated in this study. Using a modified power-law model, the tube's porosity-dependent material coefficients are graded in the radial direction. The theory of nonlocal strain gradients is used. Hamilton's principle is used to derive the size-dependent governing equations for simply-supported (S), clamped (C) and clamped-simply supported (CS). Following the solution of these equations by the extended differential quadrature technique, the effect of various factors on vibration issues was investigated further. It can be shown that these factors have a considerable effect on the vibration characteristics. It also can be found that our numerical results can capture the unexpected softening phenomena for cantilever tubes.

Key Words
free vibration; functionally graded porous tubes; higher-order theory; nonlocal strain gradient theory; various boundary conditions

Address
Xiaoping Huang: Guilin University of Technology, Guilin, Guangxi, China

Huafeng Shan: Keeson Technology Corporation Limited, Jiaxing 314000, Zhejiang, China

Weishen Chu: Department of Mechanical Engineering, the University of Texas at Austin, TX 78712, Austin, USA

Yongji Chen: Guangxi Mingxiang mechanical equipment testing Co., Ltd, Nanning, Guangxi, China

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