Synthesis, properties and uses of ZnO nanorods: a mini review

Zinc oxide (ZnO) nanorods have been extensively investigated, owing to their extraordinary applications in numerous felds, spatially microchip technology, solar cells, sensors, photodetectors, photocatalysts and many others. Recently, using ZnO nanorods, as photocatalysts, are receiving increasing attention in environmental defense applications. This mini review sum�marizes some remarkable applications for ZnO nanorods. First, the various chemical and physical procedures that were used to produce ZnO nanorods are identifed through symmetric matrices and heterogeneous structures, then the authors explain how to use these methods to produce ZnO nanorods. This mini review, also, discusses the applications of ZnO nanorods in many felds, especially in feld release, emission properties, and electron transference. Last but not least, the appropriate conclusions for future research using ZnO nanorods have been successfully explained.

Macroscopic modeling for convection of Hybrid nanofluid with magnetic effects

Hybrid nanofluid free convection within a permeable media was presented with CVFEM (control volume finite element method) including magnetic effect. Momentum equations have been updated with adding non-Darcy model terms. Hybrid nanoparticles (Fe3O4+MWCNT) with a base fluid of water have been considered. Impacts of Darcy number, magnetic, radiation, and Rayleigh number on migration of nanomaterial were depicted. A numerical and graphical comparison is also presented to make sure that the present analysis is correct. From the graphical results it is found that radiation parameter and magnetic boosts the Nusselt number whereas the magnetic effect shows converse relation

Forced convection around horizontal tubes bundles of a heat exchanger using a two-phase mixture model: Effects of nanofluid and tubes Configuration

In this paper, numerical simulation of laminar flow and heat transfer of nanofluid on a group of heat exchanger tubes is described. For better prediction of the behavior of the nanofluid flow on the tube arrays, two-phase mixture model was used. To achieve this aim, heat transfer and laminar flow of two-phase nanofluid as cooling fluid at volume fraction of 0, 2, 4, and 6% solid nanoparticles of silver and Reynolds numbers of 100 to1800 were investigated for different Configurations of tube arrays. The results indicated when the nanofluid collides with the tube arrays, the growth of heat boundary layer and gradients increase. The increase in the growth of boundary layer in the area behind the tubes was very remarkable, such that at the Reynolds number of 100, due to diffusion of the effect of wall temperature in the cooling fluid close to the wall, it had a considerable growth. Further, from the second row onwards, the slope of pressure drop coefficient diagrams was descending. Among the different Configuration s of tubes and across all the investigated Reynolds numbers, square Configuration had the maximum pressure drop coefficient as well as the highest extent of fluid momentum depreciation

Nanoparticles hydrothermal simulation in a pipe with insertion of compound turbulator analyzing entropy generation

The aim of this investigation is to investigate the H2O turbulent flow according to the nanoparticles, including copper oxide within a pipe outfitted by an innovative swirling flow generator. For the purpose of determining width effect in turbulent flow for Reynolds number, the results are analyzed. Moreover, relationships are obtained to estimate the irreversibility component. It is observed that viscous reduces directly proportional to pumping power. This means that following an increase in inlet velocity, differential pressure rises. Because of higher velocity gradient, by increasing width Sgen,f becomes greater. As turbulator with larger b is used, stronger turbulence intensity will be generated

Scolicidal activity of biosynthesized zinc oxide nanoparticles by Mentha longifolia L. leaves against Echinococcus granulosus protoscolices

Cystic echinococcosis is a public health problem in developing countries that practice sheep breeding extensively. In the current study, the protoscolicidal activity of biosynthesized zinc oxide nanoparticles (ZnO NPs) derived from Mentha longifolia L. leaf extracts was investigated. The resultant ZnO NPs were characterized by means of various analytical techniques, such as ultraviolet–visible (UV–Vis) spectrometry, Fourier transform infrared (FT-IR) spectrophotometry, X-ray difraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) analysis. The results showed that the ZnO NP had the highest scolicidal activity at 400 ppm concentration after 150 min of exposure time, showing 100% mortality rate. The treated protoscolices exhibited loss of viability with several morphological alterations. Hence, an easy and efective green synthesis of ZnO NPs, with efcient scolicidal potential, is reported in this study

The effect of inlet temperature on the irreversibility characteristics of non-Newtonian hybrid nano-fluid flow inside a minichannel counter-current hairpin heat exchanger

The goal of this work is to examine the influence of entering temperature on the entropy generation characteristics of a minichannel hairpin heat exchanger with counter-flow configuration. The working fluids are water and hybrid water–Fe3O4/carbon nanotubes (CNTs) nano-fluid (NF) that flows through the annulus side and tube side of the heat exchanger, respectively. It is assumed that the NF is non-Newtonian, and its thermal conductivity and viscosity are temperature dependent. The impact of volume fraction of Fe3O4 (uFF) and CNT nanoadditives (uCNT) as well as the Reynolds number of NF (Renf) on the Bejan number and irreversibilities due to heat transfer and fluid friction are also assessed. It was found that augmenting the temperature difference between the fluids entering the heat exchanger results in a decrease in the frictional irreversibility and an increase in the global thermal and total irreversibilities and global Bejan number. Additionally, the outcomes depicted that the global frictional and total irreversibilities and the global Bejan number intensify by boosting the Renf and uCNT, while the increase of uFF first leads to the reduction and then the increase of these parameters

Characterization of ZnO Nanoparticles Prepared from Green Synthesis Using Euphorbia Petiolata Leaves

This investigation is one of the early studies for preparation of zinc oxide (ZnO) nanoparticles from green synthesis utilizing Euphorbia petiolata leaves, which are collected from Kurdistan region in Iraq, as a reducing and stabilizing agent throughout an easy and green synthesis method. The chemical interaction of Euphorbia petiolata leaves extract with the aqueous mixture of zinc nitrate and the oxidation through galvanizing process professionally produced the reduction of the zinc ions and creation of zinc oxide nanoparticles. The steadiness, cleanliness and crystalline nature of green synthesized nanoparticles were verified by means of UV-vis spectroscopy, EDAX and XRD procedures. UV-vis spectroscopy of prepared zinc colloidal solution displayed absorption maxima at 360 nm. XRD analysis revealed that Zn nanoparticles approve the hexagonal-wurtzite construction with a typical particle size of 55-60 nm. Likewise, the pattern of promising process result in creation of nanoparticles was explained. The important advantages of this process are: short reaction-time, fast, distinct stage, environmentally friendly synthesis of the ZnO nanoparticles, removal of harmful ingredients, and reproducibility of the process

Curve-fitting on experimental thermal conductivity of motor oil under influence of hybrid nano additives containing multi-walled carbon nanotubes and zinc oxide

Hybrid nanofluids has been attracted lots of attention due to simultaneous take advantage of the properties of two or more kinds of nanoparticles in the base fluid. Carbon Nanotubes (CNTs) are utilized widely attached to metal oxide nanoparticles due to significant thermal characteristics. This study aims to assess experimentally the thermal conductivity of the hybrid nanofluid of Zinc Oxide (ZnO) and Multi-Wall CNT (MWCNT) in Engine oil (SAE 10W40). The influences of nanoparticles concentration as well as fluid’s temperature are evaluated. The experiments performed at the temperature between 25 C and 50 C and nanoparticles volume fraction from 0.05 to 0.8 %. The experimental results showed that a higher ratio of nano-lubricant thermal conductivity is achieved for a higher volume fraction and temperature of nanoparticles. According to the absence of an exact relationship to determine the thermal conductivity of ZnO-MWCNT/Engine oil, a correlation is developed based on the test measurements presented in terms of volume fraction and temperature using a curve-fitting method. A deviation analysis is also performed on the ratio of thermal conductivity achieved from the developed correlation and experimental data showing a reasonable agreemen

Mechanical Properties of Carbon Nanotubes (CNTs): A Review

In this review, the main approaches were utilized for fabrication nanostructure materials namely arc discharge, laser ablation, chemical vapor deposition, and green synthesis. Also, the advantages and disadvantages for each approach are discussed intensively. In addition, the structure and morphology of Carbon Nanotubes (CNTs), according to the number of layers CNTs classified single-wall carbon tubes (SWCTs), double wall carbon tubes (DWCTs), and multi-wall carbon tubes (MWCTs) are demonstrated in detail. SWCTs can be divided into chiral (m≠n), zigzag (m=0), and armchair (m=n) based on the geometrical arrangement of atoms or molecules. Moreover, some of the mechanical features of CNTs such as Young’s modules, strength and tensile strength, compressibility and deformability and fracture performance will be described. Throughout this review, it can be concluded that CNTs possess better mechanical features comparing with the analogous bulk or micro-scale tubes. For instance, Young’s module of CNTs increases by decreasing radius of CNTs. Furthermore, the strength and tensile strength of CNTs becomes stronger due to this covalent bond between carbon-carbon. On the other hand, compressibility and deformability will also improve due to the anisotropic feature of CNTs shape. It can be concluded that, CNTs possess a wide range of possible uses, and they can be used in nanoscale devices, electronic applications, optical operation, materials science, architecture and many more. Also, CNTs have been utilized in numerous novel applications owing to their unusual electrical features, unique strength, and heat transfer performance

Analysis of Nanopore Structure Images Using MATLAB Software

The importance of nanopores increases with time due to their application. For instance, nanopores may be used to sense molecules like DNA and RNA, single proteins, etc. Sequencing by nanopore has also a possibility to be a direct, fast, and inexpensive DNA sequencing tool. Diameters of nanopores are the main keys for mentioned sensing processes. Three segmenting methods used in this study namely Thresholding, Gaussian Mixture Model-Expectation Maximization (GMM-EM) and Hidden Markov Random Field-Expectation Maximization (HMRF-EM). These methods applied on three SEM nanopore images after enhancing them through obtaining optimum parameters of CLAHE contrast-enhanced method to give high PSNR. The results of the Rand index and time of running code show that the HMRF-EM is better than GMM-EM. Hence, their segmented images are used to find out nanopore parameters including total counting pores, diameter, and porosity. The results of porosity were in good agreement with former investigations. Consequently, the HMRF-EM segmenting technique with procedures utilized in this study using image processing for finding porosity gives promising results among other examined methods