Aluminate Nanoparticles Research Articles

Exploring the Properties, Synthesis, and Applications of Magnesium Aluminate Nanoparticles

Magnesium aluminate (MgAl2O4) is a synthetic ceramic compound, characterized by a spinel structure and comprised of magnesium oxide (MgO) and aluminum oxide (Al2O3). Magnesium aluminate is esteemed for its distinctive combination of thermal, mechanical, and optical characteristics, making its role remarkable for various applications. Hence this review, focuses mainly on magnesium aluminate nanoparticles, a subject that is gaining prominent attention in the current research scenario. There are several methods available for the synthesis of MgAl2O4 nanoparticles (MANPs), including sol-gel and co-precipitation techniques, along with those that incorporate green methodologies. The high melting point, substantial hardness, and excellent thermal shock resistance of the host material suggest that MANPs could hold a significant place in the field of nanotechnology. Numerous studies have demonstrated that the introduction of different ions into MANPs through doping effectively altered their characteristics, thereby improving their functional capabilities. Thus, this review gives a comprehensive examination of the properties of magnesium aluminate, the synthesis methods utilized, impacts of doping, and various applications of magnesium aluminate nanoparticles.

Reactivity of a plagioclase concentrate from the South African Bushveld Igneous Complex via extractive acid leaching vs. extractive roasting-leaching processes

This study compared the reactivity of a plagioclase concentrate subjected to two processes: (1) direct acid leaching and (2) thermochemical treatment with ammonium sulfate followed by leaching. The sample was prepared from coarse-grained pyroxenite rock retrieved from the Bushveld Igneous Complex, South Africa. It contained 78% plagioclase (labradorite), 9% orthopyroxene (enstatite) and 13% quartz. The elements contained in the concentrate were categorized into three groups based on their susceptibility to direct acid extraction after 6 h of leaching. Group 1 consisted of the highly reactive main elements of plagioclase (Al, Ca and Na, with extraction efficiencies of 95%, 89% and 81%, respectively). Group 2 included elements predominantly present in enstatite (Mg and Fe with extraction efficiencies of 41% and 55%, respectively). Group 3 was composed of slowly extractable Si (25%) from mostly plagioclase. Increasing the duration of direct acid leaching to 24 h had no effect on the extraction of Group 1 elements, whereas the extraction of Mg and Fe (Group 2) increased to >60%, and that of Si (Group 3) increased from 25 to 80%. The latter correlated with the nearly complete disappearance of the plagioclase blueprint in the XRD pattern of the residues generated after 24 h of leaching. In contrast, plagioclase had limited reactivity with ammonium sulfate during thermochemical treatment. Direct acid leaching of plagioclase-rich tailings can therefore generate leachates to be used as precursors for the preparation of value-added products, such as silica nanoparticles via a sol–gel route and calcium aluminate nanoparticles via solution combustion.

Bioinspired synthesis of calcium magnesium aluminate nanoparticles using aloe vera extract: A promising material for electrochemical sensors, antibacterial and environmental remediation applications

Aloe vera (Aloe barbadensis miller) leaf extract was used in green fuel-assisted microwave synthesis to prepare Calcium Magnesium Aluminate (CMA). The synthesized CMA was characterized by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), Scanning electron microscope (SEM), Energy dispersion spectrometer (EDAX), and Transmission Electron Microscopy (TEM) analyses. X-ray diffraction confirmed the formation of Ca2Mg2Al28O46. The UV–Vis diffuse reflectance (DRS) technique was employed to investigate its absorbance spectrum, and the band gap of CMA was found to be 4.9 eV. The CMA nanoparticles were used to design a sensing electrode for creatinine, enabling the determination of its concentration in human samples and heavy metals. Acid Orange-88 dye was degraded using CMA nanoparticles as a photocatalyst under UV irradiation. After dye degradation, treated water was used to grow Vigna radiata plants to test their suitability for seedling growth. This report demonstrates that CMA photocatalysts are alternatives to semiconductor photocatalysts for the degradation of Acid Orange-88 dye under UV illumination. Escherichia coli (E. coli), Staphylococcus species, and Pseudomonas species were used as model organisms to assess the antibacterial activity of CMA NPs through a green route.

Оценка бионакопления и токсического действия наночастиц кобальт (ii) алюмината для задач обеспечения гигиенической безопасности

Hygienic safety plays an important role in preventing health harm under chemical exposures. Hygienic regulation of levels of existing and new substances in environmental objects is the core element here carried out within experimental research aimed at establishing their toxic properties. Cobalt (II) aluminate nanoparticles (CoAl2O4 NPs) are a typical example of a new material with presumably higher toxic potential upon oral exposure as opposed to micro-sized particles (MPs). Given that, the development of safety standards requires identifying features of the negative impact of CoAl2O4 NPs, which are different from MPs upon oral exposure. The study was performed on Wistar rats orally exposed to NPs and MPs for 20 days at the total dose of 10,550 mg/kg of body weight. NPs have chemical composition similar to MPs, smaller size (87.11 times) and larger specific surface area (1.74 times). NPs have a more pronounced ability to bioaccumulate in the heart, lungs, liver and kidneys as compared to MPs (up to 7.54 times). Exposure to NPs resulted in more pronounced (up to 3.60 times) changes in blood indicators associated with developing redox imbalance, cytotoxic effect, liver, pancreas and kidney dysfunction, inflammatory process, and thrombocytopenia. NPs caused hemorrhagic infarcts and pulmonary edema not established upon MPs exposures. The calculated value of the tentatively permissible exposure level (TPEL) was 0.02 mg/dm3 for these NPs content in drinking water, which is 10 times lower than the same value for MPs. Thus, CoAl2O4 NPs upon oral exposure for 20 days at the total dose of 10,550 mg/kg of body weight have more marked bioaccumulation relative to MPs, which causes more pronounced negative effects identified by changes in blood indicators and developing pathomorphological changes. The study findings allow increasing accuracy and objectivity when developing safety standards for CoAl2O4 levels in food products and drinking water to ensure greater hygienic safety of the population.

Assessment of bioaccumulation and toxic effects of Cobalt (II) aluminate nanoparticles for hygienic safety purposes

Hygienic safety plays an important role in preventing health harm under chemical exposures. Hygienic regulation of levels of existing and new substances in environmental objects is the core element here carried out within experimental research aimed at establishing their toxic properties. Cobalt (II) aluminate nanoparticles (CoAl2O4 NPs) are a typical example of a new material with presumably higher toxic potential upon oral exposure as opposed to micro-sized particles (MPs). Given that, the development of safety standards requires identifying features of the negative impact of CoAl2O4 NPs, which are different from MPs upon oral exposure. The study was performed on Wistar rats orally exposed to NPs and MPs for 20 days at the total dose of 10,550 mg/kg of body weight. NPs have chemical composition similar to MPs, smaller size (87.11 times) and larger specific surface area (1.74 times). NPs have a more pronounced ability to bioaccumulate in the heart, lungs, liver and kidneys as compared to MPs (up to 7.54 times). Exposure to NPs resulted in more pronounced (up to 3.60 times) changes in blood indicators associated with developing redox imbalance, cytotoxic effect, liver, pancreas and kidney dysfunction, inflammatory process, and thrombocytopenia. NPs caused hemorrhagic infarcts and pulmonary edema not established upon MPs exposures. The calculated value of the tentatively permissible exposure level (TPEL) was 0.02 mg/dm3 for these NPs content in drinking water, which is 10 times lower than the same value for MPs. Thus, CoAl2O4 NPs upon oral exposure for 20 days at the total dose of 10,550 mg/kg of body weight have more marked bioaccumulation relative to MPs, which causes more pronounced negative effects identified by changes in blood indicators and developing pathomorphological changes. The study findings allow increasing accuracy and objectivity when developing safety standards for CoAl2O4 levels in food products and drinking water to ensure greater hygienic safety of the population.

Effect of Sm3+ concentration on reddish orange photoluminescence and electrochemical properties of copper aluminate nanoparticles for display and supercapacitor applications

In this report, a novel synthesis method for Sm3+-doped copper aluminate nanoparticles (1–9 mol %) is presented, utilizing Ocimumsanctum leaves extract as a reducing agent through the solution combustion method, followed by calcination at 600 °C for 3 h. The resulting cubic spinel structure, validated by Bragg reflections, demonstrates a decrease in crystallite size and a direct energy band gap correlated with increasing dopant concentration. The morphology exhibits irregularly shaped nanoparticles and hexagonal shaped nanoplates. On deconvolution, three peaks situated at 579, 590 and 600 nm. The emission peak observed at 579 and 590/600 nm can be attributed to transitions from excited level G5/24 to its lower lying levels, H5/26, H7/26 respectively, with noticeable concentration quenching at 7 mol %. CIE and CCT coordinates affirm the red emission of Sm3+ within the host lattice, suggesting potential applications in residential and hospital settings. Cyclic voltammetry analysis provides insights into redox reactions, electrode kinetics, and electrochemical behavior. Electrochemical Impedance Spectroscopy (EIS) elucidates ion transport kinetics, while Galvanostatic Charge–Discharge (GCD) analysis determines supercapacitance values ranging from 53.89 F/g with increasing dopant concentrations. This material exhibits promise for applications in energy storage and display technology.

Dielectric study and electrochemical detection of ascorbic acid using modified electrode treated with europium-doped tricalcium aluminate nanoparticles

The current study involved the dielectric, and sensor properties of trivalent europium (Eu3+) doped tricalcium aluminate (Ca3Al2O6) Nanoparticles. These samples were synthesized through the solution combustion method with urea (NH2CO·NH2) as the fuel. Structural analysis confirms that the samples exhibited a sustainable cubic phase with the Pm-3m space group. The irregular spherical morphology and agglomeration of synthesized particles were observed using a scanning electron microscope. The energy bandgap values were calculated using the Kubelka and Munk relation, which ranged from 5.14 to 5.27 eV. To examine the dielectric behavior at different frequencies, electrical impedance spectroscopy was performed which provided insights into the changes in electrical permittivity and revealed the contributions of both grains and grain boundaries in the samples. The synthesized material exhibited higher values of dielectric constant and loss at lower frequencies, which decreased significantly as the frequency increased. This suggests that the samples are suitable for applications in microwave devices. Also, the electrochemical studies demonstrate the sensor's rapid amperometric response to ascorbic acid oxidation. The current constructed sensor has a sensitivity of 0.0065 A for ascorbic acid and the electrode treated with Ca3-xAl2O6:xEu3+ (x = 0.05) is better able to detect the electrochemical behavior of substances like ascorbic acid.

Concentration-dependent luminescence characterization of terbium-doped strontium aluminate nanophosphors.

The present investigation describes the synthesis of luminescent terbium-doped strontium aluminate nanoparticles emitting bright green light, which were synthesized through a solid-state reaction method assisted by microwave radiation. Various samples containing different concentrations of Tb were synthesized, and an analysis of their structural and morphological features was conducted using powder x-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The band gaps of the samples were determined utilizing the Kubelka-Munk method. The quenching mechanism observed was identified to be due to dipole-dipole interaction using the Dexter theory. The optimized sample with a terbium concentration of 4at.% has a luminescence lifetime of 1.05 ms with 20.62% quantum efficiency. The results of this study indicate that the terbium-doped strontium aluminate fluorescent nanoparticles exhibit promising potential for a wide range of applications, including bioimaging, sensing and solid-state lighting.

Influence of Nd3+ ions modified CoAl2O4 nanomaterials for high efficiency dye degradation application

This study aims to elucidate the possible application of cobalt aluminate nanoparticles (CoAl2O4) as a photocatalyst for the removal of organic dyes. The sol-gel method was employed to synthesise Ndx/CoAl2O4 nanoparticles with varying weight percentages (x = 0.0, 0.2, 0.4, and 0.6 wt %). The experimental investigation focused on the photocatalytic destruction of colour, employing a visible light irradiation source. The structural and optical properties of the synthesised nanoparticle were examined through various analytical techniques, including X-Ray Diffraction (XRD), Ultra Violet-Diffuse Reflectance Spectroscopy (UV-DRS), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX), Tunnelling Electron Microscopy (TEM), and X-ray Photoelectron Spectroscopy (XPS). The cubic spinel structure was confirmed through the study of the X-ray diffraction (XRD) pattern of the Ndx/CoAl2O4 nanoparticles. For the compositions x = 0.0, 0.2, 0.4, and 0.6, the nanoparticles exhibited average crystallite sizes of 23.73, 22.99, 21.69, and 21.65 nm, respectively. The synthesised nanoparticle exhibited heterogeneous photocatalytic potential when employed as a model pollutant for the oxidative destruction of crystal violet dye. The experimental findings validated that the CoAl2O4 nanoparticle exhibited a dye degradation rate of 64 % during a 100-min timeframe. Additionally, the 0.6 wt % Nd CoAl2O4 nanoparticle shows a quick dye degradation rate of 91 % for crystal violet dyes when exposed to visible light sources. Hence, the synthesised nanoparticle exhibits catalytic activity and holds potential for utilisation in the treatment of hazardous contaminants in industrial wastewater.

Preparation of multifunctional and mechanically-reliable smart wood infiltrated with cellulose nanocrystal-reinforced polyvinyl alcohol nanocomposite

Multifunctional transparent woods have recently attracted a great interest as efficient products for many applications, such as smart window and smart packaging. Herein, a transparent wood with several desirable properties, including flame-retardant activity, ultraviolet shielding, superhydrophobicity, good roughness, durability and photostability was developed. The current photoluminescent wood showed a remarkable capacity to keep releasing light in the dark for extended durations. Multifunctional transparent wood was prepared by infiltrating a delignified wooden bulk with a combination of polyvinyl alcohol (PVA), ammonium polyphosphate (APP), cellulose nanocrystals, and rare-earth strontium aluminate nanoparticles (RSAN). Cellulose nanocrystals were prepared from microcrystalline cellulose, and used as reinforcement nanofiller to enhance the mechanical strength of the polyvinyl alcohol matrix and a dispersant agent to avoid agglomeration of RSAN. RSAN displayed diameters of 8–16 nm, while cellulose nanocrystals displayed lengths of 75–150 nm and diameters of 5–10 nm. According to photoluminescence spectra and the colorimetric space coordinates reported by the CIE Lab parameters, the transparent wood changed color to bright green when exposed to UV irradiation. For the produced phosphorescent wood surfaces, an absorption band was detected at 365 nm to generate an emission band at 519 nm.

Thermal transport of radially magnetized peristalsis of non-Newtonian nanofluid through an asymmetric curved channel

Present examination explores the heat and mass transfer phenomena for magnetohydrodynamics (MHD) peristaltic transport of diethylene glycol (DEG)-based Cross nanofluid through an asymmetric curved channel. The mass and thermal characteristics of nanofluid are established through the assessment of Buongiorno nano-liquid model, which allows to identify intriguing features of thermophoretic and Brownian diffusion coefficients. Further, velocity slip conditions are enforced on the peristaltic walls. The influences of thermal radiation, radius-dependent magnetic field and viscous dissipation are also taken into consideration. The governing equations are simplified by employing lubrication theory (“biological estimate of the creeping transportation phenomenon”), and resulting system is tackled numerically. Impacts of different flow parameters on the nanofluid’s velocity, nanomaterials concentration profile, heat and mass transfer, streamlines, temperature of nanofluid, and stresses at the wall are analyzed via graphs and tables. The findings of this investigation report that nanofluid’s temperature enhances against Hartmann and Brinkman numbers, whereas it declines for the thermal radiation parameter. The distribution of the concentration profile decreases for Brownian motion while it increases for the thermophoresis parameter. Further, a development in the stresses, thermal and mass transfer rates at the boundary is seen for better values of the Hartmann number. Additionally, higher values of the velocity slip parameter show increasing behavior for the velocity of nanofluid near the walls of the channel. The effects of MHD with magnesium aluminate nanoparticles suspended in DEG base fluid-based nanofluid through an asymmetric curved conduit have many uses in industry, organic compounds, biomedical engineering, and commercial productions, such as brake fluid, tobacco, polyester resins, certain dyes, printing ink, polyurethanes, glue, resins, antifreeze, nitrocellulose, oils, cigarettes, plasticizers, and so forth. DEG-based nanofluids are also used in human medications, including acetaminophen and sulfanilamide, which can result in incidents of human poisoning, some of which have been fatal, either intentionally or unintentionally.

Fabrication of nickel aluminate based electrochemical sensor for dopamine detection

Nickel aluminate nanoparticles (NiAl2O4 NPs) spinel structure is synthesized via a simple solution combustion method using aqueous nickel nitrate, aluminum nitrate and citric acid. The crystal structure and microstructure of the prepared NiAl2O4 NPs are confirmed by powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectrum, scanning and transmission electron microscopy (SEM/TEM). The characterized NiAl2O4 NPs are applied on a glassy carbon electrode (GCE) to design electrochemical sensor for the detection of dopamine (DA) using cyclic voltammograms (CV) and differential pulse anodic stripping voltammograms. The proposed electrochemical sensor exhibits excellent sensing activity with a low detection limit of 1.78 μM and applicable for a wide linear concentration range of 10 μM–140 μM. Further, the proposed electrode exhibits well resolved differential pulse voltammogram for the dopamine in presence of interfering uric acid and ascorbic acid.

Surface-silanized glass nanofibers and aluminate nanoparticles as reinforcing agents for acrylic emulsion toward multifunctional stimuli-responsive composite coatings

Smart waterborne coatings have shown various functions, such as afterglow photoluminescence, antimicrobial activity, water resistance, ultraviolet blocking, and anti-counterfeiting properties. However, photoluminescent organic agents have shown poor photostability and high cost. Additionally, waterborne acrylic coatings have shown poor mechanical properties. Herein, nanoparticles of rare-earth strontium aluminate (NRESA) and electrospun glass nanofibers (EGN) were used to strengthen the bulk of acrylic (ACR) coatings to develop smart products with mechanical reliability, hydrophobicity, ultraviolet blocking, and persistent photoluminescence. By physically integrating nano-scaled particles of RESA, colorless smart coatings of EGN@ACR were produced. Photoluminescence spectra showed that the transparent EGN@ACR changed its appearance to greenish when exposed to ultraviolet rays. Hybrids of EGN@ACR with trace amounts of NRESA showed fluorescence emission with instant reversibility. As the phosphor concentration in the EGN@ACR hybrids increased, afterglow photoluminescence with delayed reversibility was detected. When excited at 370 nm, the hybrid coatings displayed an emission band at 519 nm. The morphological analysis of NRESA by transmission electron microscopy (TEM) displayed diameters of 9–21 nm. After being prepared using electrospinning technology, glass nanofibers were introduced into acrylic emulsion coatings as a reinforcement agent. Scanning electron microscopic (SEM) analysis of EGN showed diameters of 70–120 nm. The smart coatings had better resistance to scratches as compared to the control sample of NRESA-free acrylic paint. A higher concentration of NRESA resulted in enhanced hydrophobicity and ultraviolet blocking.

Graphene nanosheet reinforcement of polyurethane nanocomposite for green and sustainable photoluminescence, superhydrophobic, and anticorrosive paint.

A simple and environmentally friendly method was developed for smart and efficient waterborne polyurethane (PUR) paint. Sugarcane bagasse was recycled into reduced graphene oxide nanosheets (rGONSs). Both lanthanide-doped aluminate nanoparticles (LAN; photoluminescent agent, 7-9nm) and rGONSs (reinforcement agent) were integrated into a waterborne polyurethane to produce a novel photoluminescent, hydrophobic, and anticorrosive nanocomposite coating. Using ferrocene-based oxidation under masked circumstances, graphene oxide nanosheets were produced from sugarcane bagasse. The oxidized semicarbazide (SCB) nanostructures were integrated into polyurethane coatings as a drying, anticorrosion, and crosslinking agent. Polyurethane coatings with varying amounts of phosphor pigment were prepared and subsequently applied to mild steel. The produced paints (LAN/rGONSs@PUR) were tested for their hydrophobicity, hardness, and scratch resistance. Commission Internationale de l'éclairage (CIE) Laboratory parameters and photoluminescence analysis established the opacity and colourimetric properties of the nanocomposite coatings. When excited at 365 nm, the luminescent transparent paints emitted a strong greenish light at 517 nm. The anticorrosion characteristics of the coated steel were investigated. The phosphor-containing (11% w/w) polyurethane coatings displayed the most pronounced anticorrosion capability and long-persistent luminosity. The prepared waterborne polyurethane paints were very photostable and durable.

Tb-doped strontium aluminate nanophosphor: Cytotoxicity, phytotoxicity, and bioimaging in plant cells

This study explores the novel application of terbium-doped strontium aluminate nanoparticles for fluorescence imaging in plant cells. The study encompasses microwave assisted solid state synthesis as well as the structural and optical characterization of terbium-doped strontium aluminate nanophosphors, their toxicity studies in plant and animal cells and their use as a fluorescent dye for plant imaging. The X-ray diffraction pattern analysis, along with Rietveld refinement studies, show the formation of SrAl2O4 as a dominant crystalline phase. Photoluminescence investigations demonstrate green emission from Tb3+ transition levels. In vitro biocompatibility of terbium-doped strontium aluminate nanophosphors was studied using L929 fibroblast cells. The plant Clitoria ternatea was used to examine phytotoxicity. The samples' potential for bioimaging was further investigated. Our findings reveal improved growth of seedlings, positioning these nanoparticles as promising tools in plant-related research. This study advances our understanding of nanoparticle-plant interactions and holds potential for transformative applications in agriculture.

CeAlO3 nanoparticle synthesis through combustion-assisted method and structural property assessment in Nano-CeAlO3 polymer composites

ABSTRACT This study explores enhancing epoxy polymers with cerium aluminate (CeAlO3) nanoparticles via a solution combustion process. CeAlO3 loading (0.5 to 2.5 wt.%) significantly influences resulting composite properties. Characterization techniques confirm CeAlO3 presence, porous spherical morphology, and formation. FTIR spectroscopy identifies functional groups, while TGA shows excellent thermal stability below 200 °C, with minimal mass loss, and stability at 900 °C. The composites exhibit enhanced properties, with maximum tensile strength at 0.5 wt.%, a linear increase in tensile modulus up to 2.5 wt.%, and maximum compressive strength at 0.5 wt.%, with increasing modulus at higher filler loadings. These findings suggest CeAlO3-filled epoxy composites hold promise for high-temperature applications, emphasizing the importance of low filler concentrations for optimal structural properties. Overall, this research underscores the potential of CeAlO3 nanoparticles in advancing epoxy-based materials across various industries.

Preparation of transparent electrospun nanofibrous membrane from long‐persistent phosphor‐reinforced polymer for security authentication

AbstractPhotochromic inks have been a tempting authentication method to make commercial items more resistant to counterfeiting. However, recent studies have shown that photochromic inks have major drawbacks, such as expensiveness and low durability. Herein, we report the development of new photochromic nanofibers for cutting‐edge anti‐counterfeiting uses. Lanthanide‐doped strontium aluminate nanoparticles (LSAN) were synthesized and immobilized onto electrospun polyurethane nanofibers (PUNF). Anti‐counterfeiting materials encapsulated with inorganic photochromic agent can guarantee photostability and durability. LSAN function as an efficient inorganic photochromic agent whereas PUNF function as a hosting matrix. Both of photostability and reversibility of the prepared UV‐induced photochromic LSAN@PUNF were found to be rather high. Applying varying ratios of LSAN resulted in the development of polyurethane nanofibers with distinct emission properties depending on the LSAN content. The nanofibrous films showed green emission under UV illumination, and whereas no traces were detected in visible daylight. LSAN displayed diameters of 3–6 nm, whereas LSAN@PUNF nanofibers had diameters of 150–450 nm. Transparency was indicated by an excitation peak at 347 nm, and a green color was indicated by an emission peak of 530 nm. The current approach can be presented as an efficient technology to prevent forgery of commercial products.

Study of mass and heat transfer for peristaltic transport of cross nanofluid through a curved channel

AbstractNanoparticles have significant applications in drug delivery systems, heat exchanges, treatment of several diseases and chemical reactions. The Cross non‐Newtonian nanofluid model for heat and mass transfer inspection with diethylene glycol‐based fluid is highlighted in this study. The magnesium aluminate nanoparticles are used to evaluate nanofluid characteristics. The current investigation explores the numerical results for magnetohydrodynamics (MHD) peristaltic movement of Cross‐nanofluid via a curved channel under the influences of thermal radiation, heat sink/source and Joule heating. The effects of viscous dissipation, thermophoretic, variable thermal conductivity and Brownian diffusion coefficients in the presence of mass and thermal convection are also taken into consideration. Flow problem is modeled using fundamental conservation laws, and the resulting nonlinear partial differential equations (PDEs) are reduced to a system of nonlinear ordinary differential equations (ODEs) by employing long wavelength and a small Reynolds number approximations. Simplified systems of ODEs are addressed by adopting numerical technique via the NDSolve built‐in command in Mathematica. Furthermore, graphical presentations explain the behavior of relevant flow parameters. Results indicate that better values of the magnetic number and the thermophoresis parameter increase the rate of mass transfer. Results indicate that the nanofluid's temperature increases by improving values of the Brinkman number and falls with the thermal radiation parameter. It is also stated that the nanofluid's velocity reduces near the lower wall for greater values of Hartman number. Moreover, heat transfer rate improves for larger values of the heat generation parameter and curvature parameter.

Immobilization of rare-earth doped aluminate nanoparticles encapsulated with silica into polylactic acid-based color-tunable smart plastic window

An inorganic/organic nanocomposite was used to develop an afterglow and color-tunable smart window. A combination of polylactic acid (PLA) plastic waste as an environmentally-friendly hosting agent, and lanthanide-activated strontium aluminum oxide nanoparticles (SAON) encapsulated with silica nanoparticles (SAON@Silica) as a photoluminescent efficient agent resulted in a smart organic/inorganic nanocomposite. In order to prepare SAON-encapsulated silica nanoparticles (SAON@Silica), the SAON nanoparticles were coated with silica using the heterogeneous precipitation method. By using transmission electron microscopy (TEM), SAON showed a diameter range of 5–12 nm, while the SAON@Silica nanoparticles showed a diameter range of 50–100 nm. In order to ensure the development of a colorless plastic film, a homogeneous dispersion of the phosphorescent Phosphor@Silica nanoparticles throughout the plastic bulk was confirmed. CIE Lab coordinates and luminescence spectra were used to study the color shift characteristics. Under visible light conditions, the plastic films were transparent. The photoluminescent films emitted green light at 525 nm when excited at 375 nm. The hydrophobicity and ultraviolet protection were enhanced without altering the fundamental physico-mechanical performance of the plastic sheet. The current color-tunable plastic can be used in many potential applications, such as warning signs, anti-counterfeiting barcodes, smart windows, and protective apparel.

Glass nanofibers and lanthanide aluminate nanoparticles as reinforcement nanofillers for polyurethane composite toward smart applications

Mechanically reliable photoluminescent bricks were prepared from polyurethane (PUR) by reinforcement with electrospun glass nanofibers (EGNF). To enhance the mechanical qualities of the PUR sheets, EGNF were electrospun and applied to the PUR sheets as a reinforcement agent. We physically incorporated nanoparticles of rare-earth doped strontium aluminate (NRSA) into EGNF@PUR bricks to create photoluminescent and photochromic properties. In order to confirm the transparency of EGNF@PUR with the ability to change color to greenish beneath ultraviolet irradiation, both photoluminescence spectra and CIE (Commission Internationale de l'Eclairage) Lab coordinates were examined. When irradiated at 365 nm, an emission peak was monitored at 519 nm. With low concentrations of NRSA, the emission characteristic of the EGNF@PUR hybrid bricks was immediately reversible, revealing fluorescence emission. Persistent emission with delayed reversibility was observed in EGNF@PUR when using high concentrations of NRSA. Examining the morphological properties of NRSA and EGNF using transmission electron microscopy (TEM) revealed diameters of 4-9 nm and 75-125 nm, respectively. Both EGNF and EGNF@PUR bricks were subjected to morphological analysis using different analytical methodologies. As the concentration of NRSA rose, the material became more hydrophobic and more ultraviolet-protective. When compared to NRSA-free EGNF@PUR bricks, those containing NRSA had superior scratch resistance.