Cylindrical Nanoparticles Research Articles

Design and Experimental Demonstration of Wavelength‐Selective Metamirrors on Sapphire Substrates

The increasing demand for novel mirror coating designs for new generation of gravitational wave detectors is stimulating significant research interest in investigations of reflective properties of metasurfaces. Given this strong interest, this article details a systematic methodology for fabricating reflecting metasurfaces (metamirrors) designed to operate at target wavelengths of 1064 or 1550 nm. The proposed metasurfaces consist of silicon cylindrical nanoparticles placed on a sapphire substrate. First, the dimensional parameters of the structures are thoroughly selected through numerical simulations combined with material characterization. The configurations are subsequently analyzed analytically to reveal the mirror effect, which arises from the excitation of electric and magnetic dipole moments. Following this, the metasurfaces are fabricated and experimentally characterized, demonstrating reflectivity exceeding 95% around the design wavelengths, which is in good agreement with theoretical predictions. Overall, the work demonstrates the feasibility and detailed methodology for the fabrication of thin, lightweight metamirrors capable of achieving near‐perfect reflectivity at the specified target wavelengths.

Impact of nanoparticle shape on the thermal performance of eco-friendly soybean-based nanofluids in cooling titanium alloys

Ecofriendly soybean coolant offers a sustainable alternative to conventional coolants, providing excellent thermal performance while reducing environmental impact. Its biodegradable nature and low toxicity make it a safe choice for various cooling applications, promoting greener industrial practices. This study investigates the thermal performance of eco-friendly soybean nanofluids dispersed with alumina and molybdenum disulfide (MoS2) nanoparticles for cooling a titanium alloy block. The investigations are conducted using single and dual nozzle setup to assess the impact of nanoparticle shape, volume fraction and Reynolds number on heat transfer characteristics of ecofriendy coolant. The discretization is conducted using the finite volume method, and the Nusselt number is calculated from the convective heat transfer coefficient. Results show that platelet-shaped nanoparticles exhibit superior thermal conductivity and heat transfer performance compared to spherical and cylindrical shapes. Increasing the volume fraction of MoS2 platelet-shaped nanoparticles from 0.5% to 6% results in a reduction of the average temperature distribution of the titanium block by 26.53% in the single-nozzle setup and 28.87% in the dual-nozzle configuration. The dual nozzle arrangements significantly enhance heat dissipation, with MoS2 nanoparticles decreasing the temperature distribution by 9.24% in the single-nozzle setup and 15.78% in the dual-nozzle setup compared to alumina nanoparticles. Optimal thermal performance is observed at elevated Reynolds numbers, where platelet-shaped MoS2 nanoparticles achieve the highest Nusselt numbers. Specifically, incorporating MoS2 cylindrical-shaped nanoparticles into soybean oil at higher Reynolds numbers improves average heat transfer by up to 29.16% when compared to cylindrical alumina nanoparticles. The enhancements in heat transfer for spherical and platelet-shaped MoS2 nanoparticles are 37.51% and 46.66%, respectively, relative to cylindrical alumina particles. This research offers crucial guidance on developing and enhancing sustainable coolants, revealing the significance of nanoparticle shape in optimizing thermal performance and paving the way for cleaner production processes that prioritize environmental responsibility.

Optimization of optical properties of nanocomposite films incorporating CWO and ITO nanoparticles for energy-saving window applications

Cesium tungsten oxide (CWO) and indium tin oxide (ITO) nanoparticles are potential candidates for application in energy-saving windows. However, most optical studies on these nanocomposite films lack systematic evaluation and design methods. In this work, the optical properties of spherical and cylindrical CWO and ITO nanoparticles under different geometric parameters based on the Lorenz–Mie and T-matrix theories are investigated, and spectral responses of CWO-PDMS and ITO-PDMS windows are calculated by solving the radiative transfer equation (RTE) using the Monte Carlo method. By evaluating and optimizing the geometric parameters of the nanocomposite films, energy-saving windows exhibit excellent optical performance, with a visible light transmittance that meets the indoor needs of the human eye (Tlum is about 0.6), and can shield most near-infrared light, especially CWO-PDMS windows (TNIR=0.04). Finally, a building energy consumption simulation analysis based on Energy Plus is conducted in three different cities: Jinan, Hong Kong, and Singapore. The results indicate that by adjusting the geometric parameters of nanoparticles, energy-saving windows can effectively reduce energy consumption in tropical and subtropical regions. This work provides guidance for the subsequent commercialization and experimental analysis of spectral selective composite films.

Magnetic field enhanced terahertz emission from metallic nanostructures with response to laser spatial profile distribution

This communication proposes an analytical model that exhibits terahertz (THz) radiation generation from spatially corrugated noble-metal spherical and cylindrical nanoparticles (NPs) placed under the influence of an externally applied static magnetic field. This scheme involves the resonant excitation of THz radiation through the beat-wave of two lasers in the presence of ponderomotive nonlinearities. Effect of magnetic field as well as laser intensity profiles, which include super, cosh, flat-top and ring-shaped Gaussian profiles, have been investigated. The incorporation of the magnetic field induces substantially more dynamic laser-metal coupling and influences the surface plasmon resonance condition associated with electrons of the NPs, thereby leading to stronger THz emission. Our results also demonstrate that the spatial profile of the laser affects the THz output, as it impacts the excitation and dynamics of the NPs. Additionally, we find that both the shape, size and interparticle-separation of NPs play crucial roles in enhancing THz generation. Furthermore, we explore the effects of varying other parameters like electric field strength and beam waist of incident lasers. These findings provide valuable insights for the design and optimization of THz sources based on NP systems, offering new avenues for applications in spectroscopy, imaging, communication and biomedical sciences.

Magnetic field enhanced laser absorption on a metallic surface incorporated with shape-dependent nanostructures

Abstract This communication proposes an analytical model to investigate the nanoparticle-based nonlinear absorption phenomenon associated with an obliquely incident p-polarized laser beam on a metallic surface. In this scheme, the surface is ingrained with noble-metal spherical nanoparticles and cylindrical nanoparticles in the presence of an external static magnetic field. The absorption of laser energy in the presence of nanoparticles (NPs) is attributed to surface plasmon resonance and enhanced magnetic-field effects. The absorption phenomenon is significantly enhanced by the incorporation of nanostructures and a magnetic field. The ellipticity characterizing parameter, which significantly influences the resonant frequency of different nanometric structures, has also been analysed and discussed. The effects of varying the magnetic field intensity, incident angle, size, and spacing of the NP were examined to determine their influence on the anomalous absorption of the laser. Furthermore, a direct dependency was found between the absorption coefficient and transmission coefficient of the incident laser, as well as the dimensions of the NPs. Several applications have direct relevance to this study, including biosensors such as DNA sensors and immunosensors, photothermal therapy, photoacoustic imaging, optoelectronic devices, solar cells, and surface-enhanced Raman spectroscopy.

Magnetic field enhanced terahertz generation from shape-dependent metallic nanoparticles

Abstract This communication deals with the analytical study of terahertz (THz) generation via frequency-difference mechanism using two circularly symmetric Gaussian laser beams with slightly different frequencies ω 1 and ω 2 and wave vectors k → 1 and k → 2 simultaneously propagating through a mixture of spatially corrugated noble-metal nanoparticles. The mixture, consisting of spherical nanoparticles (SNPs) and cylindrical nanoparticles (CNPs), is placed in a host medium under the influence of an externally applied static magnetic field. The two co-propagating laser beams impart a nonlinear ponderomotive force on the electrons of the NPs, causing them to experience nonlinear oscillatory velocity. Furthermore, the consequent nonlinear current density excites THz radiation at the beat frequency ω ( = ω 1 − ω 2 ) . Magnetic fields influence the surface plasmon resonance condition associated with electrons of the nanoparticles due to enhancement in ponderomotive nonlinearities, thereby causing an increment in the amplitude of the generated THz field. It is observed that the generated THz radiation has a strong dependence on the shape and size of the NPs in addition to the magnetic field strength. CNPSs provide greater THz amplitude than SNPs due to additional resonance modes, and combining both kinds of nanostructures further enhances the amplitude. THz radiation plays an important role in biomedical and pharmaceutical fields, communications, security and THz spectroscopy.

A numerical inquiry of the MHD radiative thin film nanofluid flow and heat transfer augmentation for Ni and Ta nanoparticles of different shapes dispersed in C 12 H 26–C 15 H 32 over an unsteady, curved stretching surface

Thin films are a versatile technology used in various industries, including light-emitting diodes, magnetic recording media, electronic device manufacturing, and optical coating. They are crucial for studying quantum phenomena, superlattices, and multiferroic materials. Their small size allows for better thermal transport studies due to the combination of thin film flow and nanoparticles. Therefore, this study aims to investigate thin film flow and heat transfer with the effects of thermal radiations, magnetic field, and velocity slip in association with tantalum ( Ta ) and nickel ( Ni ) nanoparticles that emerged in kerosene oil ( C 12 H 26 − C 15 H 32 ) toward a curved stretching surface. A review of the pertinent literature indicates that no research has previously been done on the present problem of an unsteady thin film flow across a curved stretching surface. The problem under consideration is modeled by choosing the curvilinear coordinate system. The controlling nonlinear system of partial differential equations is transformed into the system of ordinary differential equations by using an appropriate similarity transformation and then solved numerically using the BVP 4 C technique in MATLAB . The impact of significant physical parameters on velocity, temperature, skin friction, and Nusselt numbers are depicted through graphs and radar charts. The investigation highlights the significant influence of magnetohydrodynamics ( MHD ) , thermal radiation, volumetric fraction, and velocity slip on the enhancement of nanofluid temperature. It is also noted that cylindrical-shaped Ta nanoparticles exhibited the maximum velocity, while blade-shaped Ni nanoparticles showed the lowest. Moreover, the maximum and minimum temperatures were observed for blade-shaped Ni nanoparticles and cylindrical Ta nanoparticles, respectively. Additionally, the maximum and minimum values of skin friction are found for cylindrical Ni nanoparticles and blade-shaped Ta nanoparticles, respectively. Similarly, the maximum and minimum Nusselt numbers are recorded for cylindrical Ta nanoparticles and blade-shaped Ni nanoparticles, respectively.

Non-Darcian MHD flow of ternary-hybrid Cu-TiO2-Al2O3/H2O nanofluid over an inclined sheet with activation energy

This study has been carried out to understand the unsteady MHD slip flow of a water-based ternary hybrid nanofluid including spherical Cu, titanium dioxide TiO2 and cylindrical Al2O3 nanoparticles across an angled sheet. The complicated scenario above investigates how ternary-hybrid nanofluid behaves when it is stretched across an inclined surface in the existence of a magnetic field. In complex thermal systems such as energy-generating technologies and cooling mechanisms, an understanding of this relationship is essential. In the existence of first-order velocity slip, the heat transfer has been examined taking into account the non-Darcy Porous media, activation energy, and heat source. The study is more accommodating because of the Soret effect. The relevant similarity transformations are applied in primary equations and a built-in bvp4c program is employed for solutions. The effectiveness of the numerical approach is demonstrated by a thorough agreement with results that have been published in the past. The key conclusions are as follows: greater values of the first order slip parameter cause the flow to slow down; an increase in Soret number causes the flow to speed up; and in both scenarios—that is, with and without velocity slip, fluid movement drops caused by higher values of the chemical reaction. The Forchheimer parameter lowers fluid velocity while activation energy enhances the fluid concentration.

A numerical study on nanoparticles shape effects in modulating heat transfer in silver-water nanofluid over a polished rotating disk

Investigations of mechanical and thermodynamic aspects related to flows induced by rotating disks are of paramount importance, given their widespread application in various industrial processes. Keeping this in mind, the present study examines the influences of nanoparticles shape on heat transfer for silver-water nanofluid flow over a polished rotating disk. The nanofluid's viscosity demonstrates dependence upon temperature and nanoparticles volume fraction, considering both the cylindrical and spherical type nanoparticles. The polished disk surface proposes velocity and thermal slip at the interface. The present mathematical model also accounts for heat generation/absorption along with the aforementioned aspects. Reduction in the governing system through 'similarity transformations is carried out. The resulting system of equations are solved numerically using the built-in numerical solver NDSolve in Mathematica. Outcomes reveal that the variations in viscosity due to temperature not only impact skin friction but also the Nusselt number for given flow. Another noteworthy result is that a polished rotating disk demonstrates reduced wear and tear attributed to higher skin friction, which can be further mitigated by enhancing the velocity slip parameter. Notably, this study uncovers different impacts of cylindrical and spherical nanoparticles, advancing the understanding of heat transfer and the mechanics of rotating disc flows. Cylindrical and spherical nanoparticles exhibit distinct behaviors within the flow. This cautions engineers to carefully select nanoparticles geometries to optimize heat transfer performance based on the specific requirements of their applications. Understanding these geometry-dependent effects is essential for designing efficient heat transfer systems.

Supra-Fluorophores: Ultrabright Fluorescent Supramolecular Assemblies Derived from Conventional Fluorophores in Water.

Fluorescent organic nanoparticles (NPs) with exceptional brightness hold significant promise for demanding fluorescence bioimaging applications. Although considerable efforts are invested in developing novel organic dyes with enhanced performance, augmenting the brightness of conventional fluorophores is still one of the biggest challenges to overcome. This study presents a supramolecular strategy for constructing ultrabright fluorescent nanoparticles in aqueous media (referred to as "Supra-fluorophores") derived from conventional fluorophores. To achieve this, this course has employed a cylindrical nanoparticle with a hydrophobic microdomain, assembled by a cyclic peptide-diblock copolymer conjugate in water, as a supramolecular scaffold. The noncovalent dispersion of fluorophore moieties within the hydrophobic microdomain of the scaffold effectively mitigates the undesired aggregation-caused quenching and fluorescence quenching by water, resulting in fluorescent NPs with high brightness. This strategy is applicable to a broad spectrum of fluorophore families, covering polyaromatic hydrocarbons, coumarins, boron-dipyrromethenes, cyanines, xanthenes, and squaraines. The resulting fluorescent NPs demonstrate high fluorescence quantum yield (>30%) and brightness per volume (as high as 12060 m-1 cm-1 nm-3). Moreover, high-performance NPs with emission in the NIR region are constructed, showcasing up to 20-fold increase in both brightness and photostability. This Supra-fluorophore strategy offers a versatile and effective method for transforming existing fluorophores into ultrabright fluorescent NPs in aqueous environments, for applications such as bioimaging.

Refining shape and size of silver nanoparticles using ion irradiation for enhanced and homogeneous SERS activity

We present green synthesis of silver nanoparticles in water using unirradiated and Ag15+\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{15+}$$\\end{document} ion irradiated phytoextracts of Bergenia Ciliata leaf, Eupatorium adenophorum leaf, Rhododendron arboreum leaf and flower. The use of different plant extracts and their subsequent ion irradiation allow for successful refinement of nanoparticle size and morphology. Due to changes in reducing and capping agents the nanoparticle surface functionalization also varies which not only controls the morphology but also allows for surface oxidation and aggregation processes. In this work, we have synthesized silver nanoparticles which exhibit sizes in the range from 13 to 24 nm and having shapes like spherical, quasispherical, trigonal, hexagonal, cylindrical, dendritic assemblies, and porous nanoparticles. Owing to changes in the size and shape of the nanoparticles, their direct bandgap (2.05 eV - 2.48 eV) and local surface plasmon resonance (420 nm - 490 nm) could also be tuned. These nanoparticles are examined as SERS substrates, where their enhancement factors, limit of detection for methylene blue, and SERS substrate homogeneity have been tested. It has been observed the nanoparticles synthesized using unirradiated plant extracts present an enhancement factor of 106\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^6$$\\end{document} with a limit of detection 10-8\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{-8}$$\\end{document} M. Whereas nanoparticles with refined morphology and shapes upon irradiation present high enhancement factors of >107\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^7$$\\end{document} and detection limit down to 10-9\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{-9}$$\\end{document} M. In addition, uniformity in Raman spectra over the SERS substrates has been obtained for selected Ag NPs substrates synthesized using irradiated extracts with minimum relative standard deviation in enhancement factor < 12%.

Gold Nanorods - An Overview

This article provides an overview of current research in structure, synthesis, properties, application of gold nanorods. Interest in rod- shaped nanoparticles steam of unique optical properties, A gold nanorod is defined as nanometer-sized gold particles that are rod shaped. These solid, cylindrical nanoparticles have uniform diameters ranging from a few nanometers to hundreds of nanometers, with aspect ratios (length/diameter) larger than 1 but typically smaller than 10. The most popular and successful method for creating high-quality gold nanorods is seed-mediated development. optical properties of gold nanorods, absorption spectrum of colloidal dispersion of gold nanorods, local field effect and sensing application, color of colloidal dispersion of gold nanorod, polarization dependent color and absorption in polymer gold. Gold nanorods are utilized in a range of applications including biosensing, photothermal therapy, bioassays, biomedical imaging, and drug delivery. All these properties make gold nanorod a good candidate for future nanoelectronics in this article, we will describe the preparation and characterization of gold nanorods.

Multiple and multifocal THz emission under external periodic electric field on laser irradiation of spherical and cylindrical nanoparticles

Multiple and multifocal THz emission under external periodic electric field on laser irradiation of spherical and cylindrical nanoparticles

Parametric analysis of different Al2O3 nanoparticle shapes and expansion angles for sudden expanded tube regarding the first law of thermodynamics

The thermo-hydraulic performance of Al2O3/H2O nanofluid with different nanoparticle shapes flowing in a sudden expansion tube with variable sudden expansion inclination angles and elliptical dimpled fins with different diameters were numerically investigated. Investigation of variable sudden expansion inclination angles, elliptic dimpled fins, and different nanoparticle shapes together reveals the novelty of this study. The main purpose of this study is to analyse the effect of nanofluid particle shapes, sudden expansion inclination angles, and elliptical dimpled fin on thermo-hydraulic performance for sudden expansion tube. The platelet, cylindrical, and blade nanoparticle shapes of Al2O3 nanoparticle (φ = 1.0 %) were separately mixed into base fluid to obtain working fluid. Numerical studies were carried out under laminar flow regime (500 ≤ Re ≤ 2000). Furthermore, the sudden expansion tube was assumed to have inclination angles with α = 30°, 45°, 60°, and 90°. The results presented that the highest Performance Evaluation Criterion is obtained for the case of DT6 using Al2O3/H2O with platelet nanoparticle shape at Re = 2000. Besides, the highest Nusselt number and Performance Evaluation Criterion were realized at the inclination angle of 45°. The increment rate of Nusselt number and Performance Evaluation Criterion at α = 45° were determined as 8.75 % and 10.52 % compared to α = 30°, respectively. Moreover, elliptical dimpled fins with sized as a = 6 mm and b = 12 mm presented the highest thermo-hydraulic performance, and this condition showed an increment of 153.9 % compared to case of a = 2 mm and b = 4 mm.

Stereocomplex-Driven Morphological Transition of Coil-Rod-Coil Poly(lactic acid)-Based Cylindrical Nanoparticles.

The stereocomplexation of poly(lactic acid) (PLA) enantiomers opens up an avenue for the formation of new materials with enhanced performance, specifically regarding their mechanical and thermal resistance and resistance to hydrolysis. Despite these useful features, the study of the stereocomplexation between block copolymers based on PLA in solution is limited, and a comprehensive understanding of this phenomenon is urgently needed. Herein, triblock copolymers of poly(N-hydroxyethyl acrylamide) and PL(or D)LA in which PLA was midblock (PHEAAmy-b-PL(D)LAx-b-PHEAAmy) were synthesized and assembled into cylindrical micelles via crystallization-driven self-assembly . The stereocomplexation between enantiomeric micelles facilitates the morphological transition, and the transformation process was investigated in detail by varying the aging temperature, block composition, and solvent. It was found that the solubility of the copolymers played a vital role in determining the occurrence and the speed of the chain exchange between the micelles and the unimers, which thereafter has a significant impact on the shape transition. These results lead to a deeper understanding of the stereocomplex-driven morphological transition process and provide valuable guidance for further optimization of the transition under physiological conditions as a new category of stimuli-responsive systems for biomedical applications.

Diversified role of fuzzified particle concentration on Casson gold-blood nanofluid flow through an elongating sheet for different shape nanoparticles

The theme of this work is to explore the impact of shape factor on magnetized Casson gold-blood nanofluid flow through elongated sheet using fuzzified volume fraction. The impact of Ohmic heating, convective heating and suction/injection on heat transfer rate, is incorporated. The existing ordinary differential equations (ODEs) are transformed into fuzzy differential equations by applying the α-cut technique of fuzzy numbers. The α-cut value ranges from 0 to 1, which determines the level of fuzziness in the TFNs. The results indicate that rise in the Casson parameter leads to a reduction in the boundary layer thickness and an augmentation of shear stress near the sheet. Additionally, among the nanoparticle shapes studied, cylindrical nanoparticles demonstrate the extreme thermal conductivity, followed by platelet and blade-shaped nanoparticles, all contributing to an improvement in the heat transfer rate. The present code is validated numerically with previous works and found in good agreement.

Impact of variable thermal conductivity on flow of trihybrid nanofluid over a stretching surface.

The present article describes the impact of variable thermal conductivity on the flow of ternary hybrid nanofluid with cylindrical shape nanoparticles over a stretching surface. Three nanoparticles combine in base fluid polymer. The assumption made will be used to model an equations. Modeled equations are in the form of a system of partial differential equations are difficult to solve can be converted to system of an ordinary differential equations, through resemblance substitutions, and will be solved numerically. Numerical scheme of Runge-Kutta order four is coupled with the shooting method to solve the resulting equations. The graphs in the study illustrate how physical quantities, such as magnetic field, injection/suction, nanoparticles volume fraction, and variable thermal conductivity, affected the velocity, skin friction, temperature, and local Nusselt number. The velocity profiles deflate as the volume fraction rises. While the temperature rises with an increase in the volume fraction of nanoparticles for both injection and suction, the velocity profiles also decline as the injection and suction parameter increases. Furthermore, as the magnetic field increases, the temperature profile rises while the velocity profile falls. The temperature curves increase as thermal conductivity increases. Finally, as the magnetic field is strengthened, the Nusselt number and skin friction decrease. The combination of mathematical modeling, numerical solution techniques, and the analysis of physical quantities contributes to the advancement of knowledge in this ternary hybrid nanofluid.

Hydrothermal bioconvective Bödewadt ternary composition nanofluids flow over a stretching rotating disk through a heat generating porous medium

The bioconvective Bödewadt flow of ternary composition nanofluids over a three-dimensional stretched rotating disk is explored. The considered stream layer is filled by a porous medium and the inertia impacts are not neglected. Several physical issues are analyzed such as second order slip, strong magnetic field, thermal radiation, and temperature-dependent heat source. Also, exponential features are assumed for the heat source and Arrhenius activation energy. The components of the ternary nanofluids are spherical Al2O3 nanoparticles, MWCNT cylindrical nanoparticles and platelet graphene nanoparticles and suitable correlations for the thermophysical properties are introduced. The irreversibility properties in all the aforementioned cases are analyzed. The solution methodology depends on transforming the governing system to similar forms then they are solved using 4th order Rung-Kutta method. The obtained results disclosed that the temperature features are higher in case of ternary nanofluids compared to the hybrid and mono nanofluids cases. Also, the given outcomes recommend using the mono nanofluids to obtain lower system irreversibility.

The proportional Caputo operator approach to the thermal transport of Jeffery tri-hybrid nanofluid in a rotating frame with thermal radiation

Engine Oil is a widely used fluid in engineering problems, particularly to enhance the rate of heat transfer when these working fluids play a fundamental role. We consider engine oil as a base fluid and the suspension of different shaped (Spherical cylindrical and platelet) nanoparticles dispersed uniformly in the base fluid to enhance the working capability of engine oil. The spherical shape {text{CuO}}, platelet shape {text{Al}}_{2} {text{O}}_{3} and cylindrical shape {text{TiO}}_{2} nanoparticles are added in engine oil to constitute tri-hybrid nanofluid aiming at obtaining better thermal performance. Furthermore, we also analyze the Jeffery tri-hybrid nanofluid in a rotating frame over an infinite vertical plate. More precisely, the classical model of Jeffery tri-hybrid nanofluid is transformed into a time-fractional model by applying the newly developed constant proportional Caputo fractional derivatives. Sharp numerical results are obtained applying a Laplace transform steered approach. All the flow parameters are highlighted through graphs via MATHCAD. Furthermore, a comparative analysis between nanofluid, hybrid nanofluid and tri-hybrid nanofluid has been performed showing that tri-hybrid nanofluid has good thermal performance. The solutions of the constant proportional operator are discussed classically by taking fractional parameter α → 1. Moreover, some engineering quantities have been calculated and presented in tables. During the analysis we dispersing the mixture of nanoparticles in engine oil base fluid enhanced the heat transfer up-to18.72% which can efficiently improve the lubricity of the engine oil.

An Investigation of the Effect of Embedded Gold Nanoparticles in Different Geometric Shapes on the Directivity of THz Photoconductive Antennas

This study aims to show how Terahertz (THz) Photoconductive Antennas (PCAs) affect the radiation directivity when gold nanoparticles of various geometric shapes are embedded in the gap region between the electrodes of THz PCAs. Three different PCAs, in the frequency range of 0.1 to 2 THz, conventional and after the addition of cylindrical, triangular, square, and hexagonal geometric gold nanoparticles to the antenna gap region between the electrodes, were built and simulated. The antenna directivity increased from 4.71 dBi to 4.92 dBi when square nanoparticles were added to the bowtie PCA, from 4.33 dBi to 4.45 dBi when triangular nanoparticles were added to the dipole PCA, and from 7.18 dBi to 7.52 dBi when square nanoparticles were added to the Vivaldi PCA.