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CONTENTS
Volume 10, Number 3, March 2021
 


Abstract
The evaluation of the corrosion resistance of titanium with a TiO2 nanotubes top layer was carried out (TiO2 NT). These nanostructures were evolved into anatase nanoparticles without heat treatment in an aqueous medium, which is a novel phenomenon. This work analyzes the layer between the nanotube bottom and the substrate, which is thin and still susceptible to corrosion. The bottom of TiO2 nanotubes having Fluor resulting from the synthesis process changed between amorphous to crystalline anatase with a crystallite size of about 4 nm, which influenced the corrosion rates. Four kinds of samples were evaluated. A) NT by Ti anodizing; B) NTSB for Ti plates, either modifying its surface or anodizing the modified surface; C) NT-480 for anodized Ti and heat-treated (480oC) for reaching the anatase phase; D) NTSB-480 for Ti plates, first, modifying its surface using sandblast, after that, anodizing the modified surface, and finally, heat-treated to 480oC to compare with samples having induced crystallization and passivation. Four electrochemical techniques were used to evaluate the corrosion rates. The surfaces having TiO2 nanotubes with a sandblast pre-treatment had the highest resistance to corrosion.

Key Words
nano-tubes; photocatalytic material; characterization and application; nano-materials; nanostructured crystals

Address
(1) I. Zamudio Torres: Centro de Investigación y Desarrollo Tecnológico en Electroquímica, S.C., Parque Tecnológico Sanfandila, Pedro Escobedo, Querétaro, México; Universidad Juárez Autónoma de Tabasco, Avenida Universidad S/N, Zona de La Cultura, Col. Magisterial, Centro, Villahermosa, Tabasco, 86040, México
(2) A. Sosa Domínguez: Universidad Autónoma de Querétaro, Facultad de Química, Cerro de las Campanas s/n C.P. 76010,
Cto. Universitario, Centro Universitario, Santiago de Querétaro, Querétaro, México
(3) J.J. Pérez Bueno: Centro de Investigación y Desarrollo Tecnológico en Electroquímica, S.C., Parque Tecnológico Sanfandila, Pedro Escobedo, Querétaro, México
(4) Y. Meas: Centro de Investigación y Desarrollo Tecnológico en Electroquímica, S.C., Parque Tecnológico Sanfandila, Pedro Escobedo, Querétaro, México
(5) M.L. Mendoza López: Tecnológico Nacional de México, Instituto Tecnológico de Querétaro, Av. Tecnológico s/n Esq. M. Escobedo, Col. Centro, Santiago de Querétaro, Querétaro, México
(6) A. Dector: CONACYT, Universidad Tecnológica de San Juan del Río, Av. La Palma No. 125, Vista Hermosa, San Juan del Río, Querétaro, México





Abstract
During the previous few years, phenomenon of bioconvection along with the use of nanoparticles showed large number of applications in technological and industrial field. This paper analyzed the bioconvection phenomenon in magnetohydrodynamic boundary layer flow of a Powell-Eyring nanoliquid past a stretchable cylinder with Cattaneo-Christov heat flux. In addition, the impacts of chemical reaction and heat generation/absorption parameter are considered. By the use of appropriate transformation, the governing PDEs (nonlinear) have been transformed and formulated into nonlinear ODEs. The resulting nonlinear ODEs subjected to relevant boundary conditions are solved analytically through homotopy analysis method which is programmed in Mathematica software. Graphical and numerical results versus physical quantities like velocity, temperature, concentration and motile microorganism are investigated under the impact of physical parameters. It is noted that velocity profile enhances as the curvature parameter A and Eyring-Powell fluid parameter M increases but a decline manner for large values of buoyancy ratio parameter Nr and bio-convection Rayleigh number Rb. In the presence of Prandtl number Pr, Eyring-Powell fluid parameter M and heat absorption parameter o, temperature profile decreases. Nano particle concentration profile increases for increasing values of magnetic parameter Ha and thermophoresis parameter Nt. The motile density profile has revealed a decrement pattern for higher values of bio-convection Lewis number Lb and bio-convection peclet number Pe. This study may find uses in bio-nano coolant systems, advance nanomechanical bio-convection energy conversion equipment's etc.

Key Words
Powell-Eyring nanofluid; MHD flow; Cattaneo-Christov heat flux; heat generation/absorption; chemical reaction; bioconvection; HAM

Address
(1) Humaira Sharif, Muhammad Nawaz Naeem and Muzamal Hussain: Department of Mathematics, Govt. College University Faisalabad, 38000, Faisalabad, Pakistan
(2) Mohamed A. 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
(3) Sajjad Hussain: Department of mathematics, Govt Post graduate college, Layyah, Pakistan
(4) Abdelouahed Tounsi: YFL (Yonsei Frontier Lab), Yonsei University, Seoul, Korea; Department of Civil and Environmental Engineering, King Fahd University of Petroleum & Minerals, 31261 Dhahran, Eastern Province, Saudi Arabia







Abstract
In the current study, the free vibrational behavior of a Porous Micro (PM) beam which is integrated with Functionally Graded Piezoelectric (FGP) layers with initial curvature is considered based on the two trigonometric shear deformation theories namely SSDBT and Tan-SDBT. The structure's mechanical properties are varied through its thicknesses following the given functions. The curved microbeam is exposed to electro-mechanical preload and also is rested on a Pasternak type of elastic foundation. Hamilton's principle is used to extract the motion equations and the MCST is used to capture the size effect. Navier's solution method is selected as an analytical method to solve the motion equations for a simply supported ends case and by validating the results for a simpler state with previously published works, effects of different important parameters on the behavior of the structure are considered. It is found that although increasing the porosity reduces the natural frequency, but enhancing the volume fraction of CNTs increasing it. Also, by increasing the central angle of the curved beam the vibrations of the structure increases. Designing and manufacturing more efficient smart structures such as sensors and actuators are of the aims of this study.

Key Words
curved beam; porous materials; carbon nanotubes reinforced composites; sandwich structures; trigonometric shear deformation theory; modified couple stress theory

Address
(1) S. Behnam Mousavi and Akbar Jafari: Department of Mechanical Engineering, Sirjan University of Technology, Sirjan, Iran
(2) Saeed Amir and Ehsan Arshid: Department of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran

Abstract
Polydimethylsiloxane (PDMS) is one of the most widely adopted silicon-based organic polymeric elastomers. Elastomeric nanostructures are normally required to accomplish an explicit mechanical role and correspondingly their mechanical properties are crucial to affect device and material performance. Despite its wide application, the mechanical properties of PDMS are yet fully understood. In particular, the time dependent mechanical response of PDMS has not been fully elucidated. Here, utilizing state-of-the-art PeakForce Quantitative Nanomechanical Mapping (PFQNM) together with Force Volume (FV) and Fast Force Volume (FFV), the elastic moduli of PDMS samples were assessed in a time-dependent fashion. Specifically, the acquisition frequency was discretely changed four orders of magnitude from 0.1 Hz up to 2 kHz. Careful calibrations were done. Force data were fitted with a linearized DMT contact mechanics model considering surface adhesion force. Increased Young's modulus was discovered with increasing acquisition frequency. It was measured 878+-274 kPa at 0.1 Hz and increased to 4586+-758 kPa at 2 kHz. The robust local probing of mechanical measurement as well as unprecedented high-resolution topography imaging open new avenues for quantitative nanomechanical mapping of soft polymers, and can be extended to soft biological systems.

Key Words
polydimethylsiloxane (PDMS); PeakForce quantitative nanomechanical mapping (PFQNM); fast force volume (FFV); Young's modulus; DMT model; atomic force microscopy (AFM)

Address
Shuting Zhang, Yu Ji and Chunhua Ma: Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals; Key Laboratory of Green Chemical Media and Reactions, Ministry of Education; School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China


Abstract
The present manuscript focuses the effects of suction on the flow of the dusty fluid along permeable exponentially stretching cylinder. Derived PDEs for this work are changed into ODEs by adopting right transformations. Numerical procedure is carried out for the obtained resultant equations by Shooting Technique in accordance with Runge-Kutta (RK-6) technique. Obtained results for the parameters namely, particle interaction parameter, suction parameter and Reynold number parameters are probed thoroughly. Some salient points are: (a) Fluid velocity decreases and the dust phase velocity rises for the higher values of particle interaction parameter; (b) more suction produces retarding velocities for both the phases; (c) high Reynold number slows down the fluid velocity while the speed of dust phase and (d) skin friction coefficient goes high for all these parameters.

Key Words
dusty fluid; stretching cylinder; similarity transformations; exponential stretching; numerical solution

Address
(1) Waheed Iqbal, Muhammad N. Naeem and Muzamal Hussain: Department of Mathematics, Govt. College University Faisalabad, 38000, Faisalabad, Pakistan
(2) Mudassar Jalil: Department of Mathematics, COMSATS Institute of Information Technology, Park Road, Chak Shahzad, 44000 Islamabad, Pakistan
(3) Amjad Qazaq: Prince Sattam Bin Abdulaziz University, College of Engineering, Civil Engineering Department, Al-Kharj, 16273, Saudi Arabia
(4) Mohamed A. 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
(5) S.R. Mahmoud: GRC Department, Faculty of Applied Studies, King Abdulaziz University, Jeddah, Saudi Arabia
(6) E. Ghandourah: Department of Nuclear Engineering, Faculty of Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
(7) Abdelouahed Tounsi: 7YFL (Yonsei Frontier Lab), Yonsei University, Seoul, Korea; Department of Civil and Environmental Engineering, King Fahd University of Petroleum & Minerals, 31261 Dhahran, Eastern Province, Saudi Arabia



Abstract
The present work deals with an investigation on longitudinal wave propagation in nanobeams made of graphene sheets, for the first time. The nanobeam is modelled via a higher-order shear deformation theory accounts for both higher-order and thickness stretching terms. The general nonlocal strain gradient theory including nonlocality and strain gradient characteristics of size-dependency in order is used to examine the small-scale effects. This model has three-small scale coefficients in which two of them are for nonlocality and one of them applied for gradient effects. Hamilton supposition is applied to obtain the governing motion equation which is solved using a harmonic solution procedure. It is indicated that the longitudinal wave characteristics of the nanobeams are significantly influenced by the nonlocal parameters and strain gradient parameter. It is shown that higher nonlocal parameter is more efficient than lower nonlocal parameter to change longitudinal phase velocities, while the strain gradient parameter is the determining factor for their efficiency on the results.

Key Words
wave propagation; homogeneous materials; bi-Helmholtz nonlocal strain gradient theory; thickness stretching effect

Address
(1) Arameh Eyvazian and Chunwei Zhang: Structural Vibration Control Group, Qingdao University of Technology, Qingdao 266033, China
(2) Farayi Musharavati: Department of Mechanical and Industrial Engineering, College of Engineering, Qatar University, P.O. Box 2713, Doha, Qatar
(3) Afrasyab Khan: Institute of Engineering and Technology, Department of Hydraulics and Hydraulic and Pneumatic Systems, South Ural State University, Lenin Prospect 76, Chelyabinsk, 454080, Russian Federation
(4) Abdeliazim Mustafa Mohamed: Department of Civil Engineering, College of Engineering, Prince Sattam bin Abdulaziz University, Alkharj 16273, Saudi Arabia


Abstract
This paper presents a new nonlocal Hyperbolic Shear Deformation Beam Theory (HSDBT) for the free vibration of porous Functionally Graded (FG) nanobeams. A new displacement field containing integrals is proposed which involves only three variables. The present model incorporates the length scale parameter (nonlocal parameter) which can capture the small scale effect and its account for shear deformation by a hyperbolic variation of all displacements through the thickness without using the shear correction factor. It has been observed that during the manufacture of Functionally Graded Materials (FGMs), micro-voids and porosities can occur inside the material. Thus, in this work, the investigation of the free vibration analysis of FG beams taking into account the influence of these imperfections is established. Four different porosity types are considered for FG nanobeam. Material characteristics of the FG beam are supposed to vary continuously within thickness direction according to a power-law scheme which is modified to approximate material characteristics for considering the influence of porosities. Based on the nonlocal differential constitutive relations of Eringen, the equations of motion of the nanobeam are derived using Hamilton's principle. The effects of nonlocal parameter, aspect ratio, and the porosity types on the dynamic responses of the nanobeam are discussed.

Key Words
free vibration; nonlocal theory; FGMs; porosity; nanobeam; HSDBT

Address
(1) Lazreg Hadji: Laboratory of Geomatics and Sustainable Development, University of Tiaret, Algeria; Department of Mechanical Engineering, University of Tiaret, BP 78 Zaaroura, Tiaret 14000, Algeria
(2) Mehmet Avcar: Department of Civil Engineering, Suleyman Demirel University, Isparta, Turkey

Abstract
A new ionic liquid functionalized magnetic silica nanoparticle was synthesized and characterized and tested as an adsorbent. The adsorbent was used for magnetic solid phase extraction on ICP-MS method. Simultaneous determination of precious metal Au has been addressed. The method is simple and fast and has been applied to standard water and surface water analysis. A new method for separation/analysis of trace precious metal Au by Magnetron Solid Phase Extraction (MSPE) combined with ICP-MS. The element to be tested is rapidly adsorbed on CoFe2O4@SiO2@[BMIM]PF6 composite nano-adsorbent and eluted with thiourea. The method has a preconcentration factor of 9.5-fold. This method has been successfully applied to the determination of gold in actual water samples. Hydrophobic Ionic Liquids (ILs) 1-butyl-3-methylimidazole hexafluorophosphate ([BMIM]PF6) coated CoFe2O4@SiO2 nanoparticles with core-shell structure to prepare magnetic solid phase extraction agent (CoFe2O4@SiO2@ILs) and establish a new method of MSPE coupled with inductively coupled plasma mass spectrometry for separation/analysis of trace gold. The results showed that trace gold was adsorbed rapidly by CoFe2O4@SiO2@[BMIM]PF6 and eluanted by thiourea. Under the optimal conditions, preconcentration factor of the proposed method was 9.5-fold. The linear range, detection limit, correlation coefficient (R) and relative standard deviation (RSD) were found to be 0.01~1000.00 ng mL-1, 0.001 ng mL-1, 0.9990 and 3.4% (n=11, c=4.5 ng mL-1). The CoFe2O4@SiO2 nanoparticles could be used repeatedly for 8 times. This proposed method has been successfully applied to the determination of trace gold in water samples.

Key Words
gold; magnetic silica nanoparticles; magnetic solid phase extraction; [BMIM] PF6; loaded

Address
(1) Yanxia Zeng: Department of Chemical Engineering, Yangzhou University, Yangzhou City, Jiangsu Province, 225009, China; Institute of Marine Resource Development, Jiangsu Ocean University, Lianyungang, Jiangsu Province, 222005, China
(2) Xiashi Zhu: Department of Chemical Engineering, Yangzhou University, Yangzhou City, Jiangsu Province, 225009, China
(3) Jiliang Xie and Li Chen: Institute of Marine Resource Development, Jiangsu Ocean University, Lianyungang, Jiangsu Province, 222005, China


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