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The purpose of this paper is to discuss the 3D micropolar hybrid (Ag-CuO/H₂O) nanofluid past rapid moving surface, where porous medium has been considered.

The model of problem was represented by highly partial differential equations which were deduced by using suitable approximations (boundary layer). Then, the governing model was converted into five combined ordinary differential equations applying proper similarity transformations. Therefore, the eminent iterative Runge–Kutta–Fehlberg method (RKF45) has been applied to solve the resulting equations.

Higher values of vortex viscosity, spin gradient viscosity and micro-inertia density parameters are reduced in horizontal direction, whereas opposite behaviour is noticed for vertical direction.

The work has not been done in the area of hybrid micropolar nanofluid. Hence, this article culminates to probe how to improve the thermal conduction and fluid flow in 3D boundary layer flow of micropolar mixture of nanoparticles driven by rapidly moving plate with convective boundary condition.

The purpose of this paper is to improve the properties of metal nanoparticles which are easy to agglomerate and hard to disperse evenly, thus limiting the application of metal nanoparticles in grease. A novel technology was proposed for modifying metal oxide to improve the dispersibility of nanoparticles.

SA-TiO2 nanoparticles were synthesized using an in-situ esterification method followed by surface modification with stearic acid. The microstructure of the nanoparticles was characterized by scanning electron microscope, transmission electron microscope and Fourier transform infrared spectroscopy and their thermal stability was evaluated by thermogravimetric analyzer. The tribological properties of the SA-TiO2 nanoparticles as additives in lithium grease were evaluated with a four-ball tester and TE77 reciprocating friction tester. The worn surfaces of the steel balls were investigated by EDS and XPS.

The prepared nanoparticles can be well dispersed in the lithium grease and possess much better tribological properties compared to traditional nanoparticles. The results indicated that the excellent tribological performance of SA-TiO2 was attributed to the chemical reaction film composing of Fe2O3, iron oxide and other organic compounds.

This paper provides a method to prevent the agglomeration of nano-TiO2 by surface modification with stearic acid. And the prepared nanoparticles can effectively improve the tribology performance of lithium grease.

The purpose of this paper is to investigate the reflective properties of titania (TiO2) nanoparticle‐based coating.

TiO2 nanoparticles, synthesised by sol‐gel method, were characterised by X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and ultraviolet‐visible absorption spectroscopy (UV‐vis). The coating material has been prepared by dispersing titania nanoparticles in an acrylic binder with different pigment to binder weight ratio. The reflectors were prepared by applying this coating material to different coating thicknesses to aluminium sheets.

In the study reported here, the coating material could produce reflectors with diffuse reflectance, ∼99 per cent, using coating material, having binder by weight ratio between 14 and 20 per cent, and thickness, 0.15 mm. On exposing the developed reflectors to different levels of illumination (upto 20,000 lux), they were still found to have diffuse reflectance of more than 96 per cent almost throughout the visible spectrum.

The fabricated reflectors find applications in commercial optical products, such as: reflective panels, luminaries, etc.

As of today, the reflective coatings used are of conventional type, which employ bulk TiO2 particles. In this study, we are reporting TiO2 nanoparticle‐based highly reflective coating. This is an original work, and, to the best of our knowledge, no one has ever reported on “TiO2 nanoparticle‐based reflective coatings”.

In recent times, there has been a growing interest in buoyancy-induced heat transfer within confined enclosures due to its frequent occurrence in heat transfer processes across diverse engineering disciplines, including electronic cooling, solar technologies, nuclear reactor systems, heat exchangers and energy storage systems. Moreover, the reduction of entropy generation holds significant importance in engineering applications, as it contributes to enhancing thermal system performance. This study, a numerical investigation, aims to analyze entropy generation and natural convection flow in an inclined square enclosure filled with Ag–MgO/water and Ag–TiO2/water hybrid nanofluids under the influence of a magnetic field. The enclosure features heated slits along its bottom and left walls. Following the Boussinesq approximation, the convective flow arises from a horizontal temperature difference between the partially heated walls and the cold right wall.

The governing equations for laminar unsteady natural convection flow in a Newtonian, incompressible mixture is solved using a Marker-and-Cell-based finite difference method within a customized MATLAB code. The hybrid nanofluid’s effective thermal conductivity and viscosity are determined using spherical nanoparticle correlations.

The numerical investigations cover various parameters, including nanoparticle volume concentration, Hartmann number, Rayleigh number, heat source/sink effects and inclination angle. As the Hartmann and Rayleigh numbers increase, there is a significant enhancement in entropy generation. The average Nusselt number experiences a substantial increase at extremely high values of the Rayleigh number and inclination.

This numerical investigation explores advanced applications involving various combinations of influential parameters, different nanoparticles, enclosure inclinations and improved designs. The goal is to control fluid flow and enhance heat transfer rates to meet the demands of the Fourth Industrial Revolution.

In a 90° tilted enclosure, the addition of 5% hybrid nanoparticles to the base fluid resulted in a 17.139% increase in the heat transfer rate for Ag–MgO nanoparticles and a 16.4185% increase for Ag–TiO2 nanoparticles compared to the base fluid. It is observed that a 5% nanoparticle volume fraction results in an increased heat transfer rate, influenced by variations in both the Darcy and Rayleigh numbers. The study demonstrates that the Ag–MgO hybrid nanofluid exhibits superior heat transfer and fluid transport performance compared to the Ag–TiO2 hybrid nanofluid. The simulations pertain to the use of hybrid magnetic nanofluids in fuel cells, solar cavity receivers and the processing of electromagnetic nanomaterials in enclosed environments.

The purpose of this paper is to modify light hollow polymer microsphere (LHPM) with titanium dioxide nanoparticles (nano-TiO2) to improve its compatibility with latex and apply the obtained nano-TiO2/LHPM composite particles in external wall thermal insulation coatings.

The nano-TiO2/LHPM composite particles were prepared via vigorous stirring. The morphology and chemical composition of the produced nano-TiO2/LHPM composite particles were characterized using scanning electron microscopy, energy dispersion spectrum, thermo-gravimetric analyzer and Fourier transform infrared. The performance of this new composite coating was evaluated by checking its stability, density, radiation reflectivity, thermal conductivity and the resulting insulation temperature difference when forming coating film.

It was found that a 9:1 mass ratio of nano-TiO2/LHPM with total 10 weight per cent composite particles in the thermal insulation paint showed low density, good stability, low thermal conductivity (0.1687 W/m·K) and high insulation temperature difference (5.8°C).

The LHPM can be modified by other nanoparticles to improve its insulation performance in thermal insulation coatings.

This work provides a simple, robust, but effective approach to produce new thermal insulation coatings with nano-TiO2/LHPM composite particles.

This method for surface modification of LHPMs is novel and the modified hollow polymer microspheres could be applied to external wall insulation coatings.

The main purpose of this study was to prepare the cotton fibers and cellulose powder by a layer of nano-crystalline-titanium dioxide (TiO₂) using the sol-gel sono-synthesis method to clean the wastewater containing reactive dye. Moreover, TiO₂ nano-materials are remarkable due to their photoactive properties and valuable applications in wastewater treatment.

In this research, TiO₂ was synthesized and deposited effectively on cotton fibers and cellulose powder using ultrasound-assisted coating. Further, tetra butyl titanate was used as a precursor to the synthesis of TiO₂ nanoparticles. Reactive dye (red 195) was used in this study. X-ray Diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy were performed to prove the aptitude for the formation of crystal TiO2 on the cotton fibers and cellulose powder along with TiO₂ nanoparticles as well as to analyze the chemical structure. Decoloration of the wastewater was investigated through ultraviolet (UV-Visible) light at 30 min.

The experimental results revealed that the decolorization was completed at 2.0 min with the cellulose nano TiO₂ treatment whereas cotton nano TiO₂ treated solution contained reactive dyestuffs even after the treatment of 2 min. This was the fastest method up to now than all reported methods for sustainable decolorization of wastewater by absorption. Furthermore, this study explored that the cellulose TiO₂ nano-composite was more effective than the cotton TiO₂ nano-composite of decoloration wastewater for the eco-friendly remedy.

Cotton fibers and cellulose powder with nano-TiO₂, and only reactive dye (red 195) were tested.

With reactive dye-containing wastewater, it seems to be easier to get rid of the dye than to retain it, especially from dyeing of yarn, fabric, apparel, and as well as other sectors where dyestuffs are used.

This research would help to reduce pollution in the environment as well as save energy and cost.

Decoloration of wastewater treatment is an essential new track with nano-crystalline TiO2 to fast and efficient cleaning of reactive dyes containing wastewater used as a raw material.

This paper aims to introduce two methods for immobilisation of TiO₂ nanoparticles on a glass plate by means of silicon resin as a medium. Then, to ensure the effectiveness of these stabilisation methods, the photocatalytic degradation and mineralisation of the dye C.I. Reactive Blue 21 (RB21), as a model organic pollutant, were compared using these immobilised systems and the suspended one utilizing UV and sunlight irradiations individually.

TiO₂ nanoparticles were supported onto a glass support by silicon resin as an adhesion agent by spraying of TiO₂ nanoparticles on the resin surface, which covered the glass plate or brushing the mixture of TiO₂ and the resin onto the glass. The characteristics of the applied nano-TiO₂ were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Brunauer

Emmett–Teller. Photocatalytic degradation and mineralisation of C.I. Reactive Blue 21 (RB21) by two immobilised systems were compared with suspended system in a batch mode under UV and sunlight irradiations after 2 h of treatment.

The results showed that these immobilised modes had efficiencies, including 82-87 per cent degradation of RB21 and 52-58 per cent decrease in chemical oxygen demand (COD) for the operational time of 120 min, comparable to that of the suspended mode (91 per cent degradation of RB21 and, consequently, COD is decreased by 65 per cent). Comparison between photocatalytic efficiencies of two immobilised systems revealed that coating by spraying method performed better than brushing one due to more available surface area of TiO₂. Finally, the results obtained from the mentioned supported systems under sunlight indicated the efficiencies about 87 to 89 per cent in comparison of the suspension system regardless of the reaction time enhancement up to 15 h compared to the UV irradiation.

In this research, the fixation of TiO₂ nanoparticles on a substrate such as normal glass by an easy, inexpensive, durable, repairable and repeatable technique for wastewater treatment was introduced. Due to the simplicity and cheapness of these stabilisation methods and as these stabilisation methods are applicable on other substrates such as concrete, ceramics, etc., you can use these methods in major scales for purification of contaminated water, for example for stabilisation of TiO₂ nanoparticles on wall pool utilized for water purification can be used.

Two introduced immobilisation methods in this study are novel. The photocatalytic efficiency of these immobilised systems in degradation of water contaminants was investigated by using these systems in degradation and mineralisation of the dye C.I. Reactive Blue 21 (RB21), as a model organic pollutant compared with same TiO₂ nanoparticles in an aqueous suspension system under UV light. Furthermore, this paper investigated replacing of inexpensive sources of UV light instead of UV lamps, and then the same photocatalytic reactions were carried out under sunlight as a UV source and degradation efficiencies by two UV sources were compared.

This paper aims to introduce constructed CeO2/TiO2 core/shell nanoparticle as sensitive substance organic compounds.

The CeO₂ nanoparticles were synthesized by hydrothermal treatment. Then CeO₂/TiO₂ core/shell was fabricated by sol–gel method preparation of TiO₂ in the presence of ceria nanoparticles and applied as the sensitive material to make a sensor.

Formation of the nanoparticles was confirmed by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM). The synthesized sensor exhibited not only good sensitivity to volatile organic compounds at room temperature but also logarithm of sensitivity versus concentrations was linear.

The sensor shows acceptable sensitivity to volatile organic compound at room temperature.

Experimental data revealed satisfactory reproducibility and short response and recovery times.

A radical mechanism for gas sensor reaction in two pathways was considered and activation energies were calculated by density functional theory (DFT) method to describe different sensitivities of tested volatile gases. The experimental results were consistent with the calculations.

This study aims to investigate the NiO nano-reinforced solder joint characteristics of ultra-fine electronic package.

Lead-free Sn-Ag-Cu (SAC) solder paste was mixed with various percentages of NiO nanoparticles to prepare the new form of nano-reinforced solder paste. The solder paste was applied to assemble the ultra-fine capacitor using the reflow soldering process. A focussed ion beam, high resolution transmission electron microscopy system equipped with energy dispersive X-ray spectroscopy (EDS) was used in this study. In addition, X-ray inspection system, field emission scanning electron microscopy coupled with EDS, X-ray photoelectron spectroscopy (XPS) and nanoindenter were used to analyse the solder void, microstructure, hardness and fillet height of the solder joint.

The experimental results revealed that the highest fillet height was obtained with the content of 0.01 Wt.% of nano-reinforced NiO, which fulfilled the reliability requirements of the international IPC standard. However, the presence of the NiO in the lead-free solder paste only slightly influenced the changes of the intermetallic layer with the increment of weighted percentage. Moreover, the simulation method was applied to observe the distribution of NiO nanoparticles in the solder joint.

The findings are expected to provide a profound understanding of nano-reinforced solder joint’s characteristics of the ultra-fine package.

This paper aims to study the Improvements in self-cleaning property of the white acrylic water-based paint by addition of different percentages of three commercially available titanium dioxide (TiO₂) nanoparticles as additives. Then, due to the risk of destruction of polymeric materials in the presence of nanoparticles, degradation of dry paint film samples was investigated for 15 days using two important chalking and yellowing factors. Finally, the TiO₂-modified paint sample with the best performance and optimum percentage of TiO₂ nanoparticles that produced desired self-cleaning and dry film properties was introduced.

Self-cleaning and dry film properties of white acrylic water-based paint were investigated by addition of three various types of commercial available TiO₂ nanoparticles (SSP-25, STA-100 and KA-100). X-ray diffraction, transmission electron microscopy and Brunauer–Emmett–Teller were used for characterization of TiO₂ samples. Colorimetric tests in decolourization of C.I. Basic Red 46 (BR46) were used for determination of self-cleaning properties of TiO₂-modified paints in comparison with unmodified paint sample. Also, paints defects such as chalking and yellowing were tested along two weeks.

The results indicated that, in all types of TiO₂ nanoparticles, by increasing the amount of TiO₂ in modified paint, self-cleaning property of the samples was enhanced. The paint containing SSP-25 indicated better self-cleaning properties than others due to its larger surface area. However, its usage above 3.5 weight per cent caused yellowing and chalking defects in dried paint film.

In this research, TiO₂-modified paint sample with the best performance in both self-cleaning and mechanical properties was selected among the nine sets of prepared paint samples. All the materials used in this research such as acrylic resin and three types of TiO₂ nanoparticles are of industrial grade. Therefore, the introduced TiO₂-modified paint sample has the potential for the commercial production as a building exterior paint.

In the present study, an attempt at introducing a self-cleaning paint sample with acceptable mechanical properties using three types of commercially available TiO₂ nanoparticles as additives and industrial grade of acrylic resin which is the most commonly used water-based resin in building paints, as binder. As far as it was searched in the literatures, the parallel study of the self-cleaning and mechanical properties of paints has not been reported as noteworthy. Self-cleaning property of the acrylic water-based paint samples was investigated by adding three types of the commercially available TiO₂ nanoparticles. Also considering the possible detrimental effects of TiO₂ nanoparticles on polymeric materials and consequently on physical properties of the paint, chalking and yellowing factors in dried paint samples were evaluated.