Nanocomposite Medium Research Articles

Determination of antifungal efficacy and phytotoxicity of a unique silica coated porous zinc oxide nanocomposite medium for slow-release agrochemicals.

In this study the antifungal efficacy and phytotoxicity of silica coated porous zinc oxide nanoparticle (SZNP) was analyzed as this nanocomposite was observed to be a suitable platform for slow release fungicides and has the promise to bring down the dosage of other agrochemicals as well. Loading and release kinetics of tricyclazole, a potent fungicide was analyzed by measuring surface area (SBET) using Brunauer-Emmett-Teller (BET) isotherm and LC-MS/MS respectively. The antifungal efficacy of ZnO nanoparticle (ZNP) and SZNP was investigated on two phytopathogenic fungi (Alternaria solani and Aspergillus niger). The morphological changes to the fungal structure due to ZNP and SZNP treatment were studied by field emission-scanning electron microscopy (FESEM). Nanoparticle mediated elevation of reactive oxygen species in fungal samples was detected by analyzing the level of superoxide dismutase, catalase, thiol content, lipid peroxidation and by 2,7-dichlorofluorescin diacetate (DCFH-DA) assay. The phytotoxicity of these two nanostructures was assessed in rice plants by measuring primary plant growth parameters. Further, the translocation of the nanocomposite in the same plant model system was examined by checking the presence of Fluorescein isothiocyanate (FITC) tagged SZNP within the plant tissue. ZNP had superior antifungal efficacy than SZNP and caused generation of more reactive oxygen species (ROS) in the fungal samples. Even then SZNP was preferred as an agrochemical delivery vehicle because unlike ZNP alone it was not toxic to plant system. Moreover, as silica in nano form is entomotoxic in nature and nano ZnO has antifungal property, both the cargo (agrochemical) and the carrier system (silica coated porous nano zinc oxide) will have a synergistic effect in crop protection.

Ultra-stable nano-micro bubbles in a biocompatible medium for safe delivery of anti-cancer drugs

We conducted a series of experimental investigations to generate laser-stimulated millimeter bubbles (MBs) around silver nanoparticles (AgNPs) and thoroughly examined the mechanism of bubble formation within this nanocomposite system. One crucial aspect we explored was the lifetime and kinetics of these bubbles, given that bubbles generated by plasmonic nanoparticles are known to be transient with short durations. Surprisingly, our findings revealed that the achieved lifetime of these MBs extended beyond seven days. This impressive longevity far surpasses what has been reported in the existing literature. Further analysis of the experimental data uncovered a significant correlation between bubble volume and its lifetime. Smaller bubbles demonstrated longer lifetimes compared to larger ones, which provided valuable insights for future applications. The experimental results not only confirmed the validity of our model and simulations but also highlighted essential characteristics, including extended lifetime, matching absorption coefficients, adherence to physical boundary conditions, and agreement with simulated system parameters. Notably, we generated these MBs around functionalized AgNPs in a biocompatible nanocomposite medium by utilizing low-power light excitation. By readily binding potent cancer drugs to AgNPs through simple physical mixing, these medications can be securely encapsulated within bubbles and precisely guided to targeted locations within the human body. This capability to deliver drugs directly to the tumor site, while minimizing contact with healthy tissues, can lead to improved treatment outcomes and reduced side effects, significantly enhancing the quality of life for cancer patients.

Silver molybdate (Ag‐PMo12) nanocomposite: An efficient catalyst for the one‐pot synthesis of 3,3‐diindolyl derivatives in aqueous medium

AbstractAn efficient methodology has been developed for the synthesis of 3,3‐di(indolyl)oxindoles and bis(indolyl)methanes under mild conditions. The efficient condensation reaction of indoles with isatin and aldehyde led to the corresponding derivatives in the presence of silver molybdate (Ag‐PMo12) nanocomposite and aqueous medium. In addition, the silver‐doped catalytic system enables the one‐pot formation of diindolyl derivatives with excellent yields, short reaction times and under environmental benign conditions.

EVALUATION OF CARBON EMISSION IN MOTORCYCLE EXHAUSTS AND ENGINE PERFORMANCE USING BIOMASS NANOFUEL PATCH

Biomass nanofluid not only utilises the most abundant waste in Malaysia but also ensures the environment’s sustainability towards low carbon emissions by reducing Greenhouse Gases (GHG). The present work investigates a renewable biomass NanoFuel Patch derived from normal pyrolysis of Empty Fruit Bunch (EFB) biomass as a pure product (EFB nano oil). The EFB nano oil will go through the patching process to become a biomass nanofuel patch. This NanoFuel Patch is attached to the motorcycle’s fuel hose and tank. It works based on the nanofluidics concept, allowing the nanomolecules to be transported via biomass fluid bound with nanocomposite fibre medium assembled in a patch adhesive. Nanofluidics minimise the adsorption of impurities, which leads to complete combustion in the engine. The engine performance and emissions of a renewable biomass nanofuel patch were investigated during a motorcycle test attached to the dynomite roller chassis dynamometer (dyno test) in the steady-state condition of a single-cylinder and four-stroke type motorcycle. The findings show that the NanoFuel Patch produced better torque and braking power compared to the standard condition. At speeds between 60 and 70 km/h, the motorcycle’s NOx emissions were lowered to 20.56% and 7.90%, respectively, in contrast to the standard condition. Compared to standard conditions, CO emission levels were lower at 80 km/h, 90 km/h, and 100 km/h, with reductions of 22.08%, 11.65%, and 35.09%, respectively. For CO2 concentration, lower production of CO2 occurred when the motorcycle ran at speeds of 60, 70 km/h, 80 km/h, 90 km/h, and 100 km/h, with percentages of 8.87%, 8.34%, 3.59%, 2.91%, and 0.78%, respectively.

Spontaneous (two-pulse) photon echo in the nanoscale structure of self-organized quantum dots

We consider the coherent response of a medium with quasi-zero-dimensional structural units in the form of a photon echo upon resonant selective pulsed excitation of interband optical transitions, the inhomogeneous broadening of which is largely determined by the polydisperse composition of the nanocomposite. The process of formation of a photon echo is analyzed, when optical excitation leads to the formation of exciton complexes by resident electrons, which are localized in nanosized microcrystals in the limiting cases of strong and weak size quantization. By studying the coherent dynamics of the components of the pseudospin electric dipole vector, an expression is derived for the macroscopic specific polarization at the moment of emission of the photon echo signal. The consideration is carried out for a model nanocomposite medium on the example of a dielectric matrix with a system of semiconducting spherical inclusions (spherical quantum dots), the distribution over the radii of which is described by the Lifshitz-Slyozov formula.

Nonlinearity in surface plasmon polaritons at interface between triple quantum dot and nanocomposite medium

This paper focuses on investigating the generation and manipulation of surface plasmon polaritons (SPPs) at the interfaces between quantum dot (QD) molecules and nanocomposite media. We utilize three different gate voltage values and incident laser field strengths to control the propagation of SPPs. We find a significant improvement in the SPPs' propagation length at the interfaces between the QD molecules and nanocomposite media. Additionally, under the Kerr effect, the gate voltage variation provides opportunities to control the SPPs' propagation. Through modifying the intensity and frequency of the incident probe field, we can manipulate various properties of SPPs at the suggested model's interfaces. Our results indicate a large enhancement in the SPPs' propagation length at the interfaces. Notably, we estimate the skin depth and wavelength of SPPs for three distinct values of the incident probe field and gate voltage applied in the QD molecules.

Application of Chebyshev-based GDQ and Newmark methods to viscothermoelasticity responses of FG composite annular systems

This study explores the thermo-viscoelasticity response of annular disks made of a functionally graded graphene platelet reinforced composite (FG-GPLRC). Random orientation is considered for GPL nanofillers. A power-law model with a controller index is also used to determine the GPL volume fraction distribution along the radial direction. The effective thermomechanical properties of the nanocomposite medium are calculated through the one-point and two-point correlation homogenization processes. The Kelvin-Voigt technique is employed to design the viscosity nature of the system. Coupled thermoelasticity is considered to attain the governing formulation because the considered disk is subjected to a sudden high temperature. Furthermore, by incorporating generalized thermoelasticity based on the Lord-Shulman concept, the physical structure of the problem is altered. The transient governing equations are solved based on a hybrid approach. The spatial dependency is solved using a Chebyshev-based generalized differential quadrature (GDQ) method, while the time dependency is calculated using an average acceleration-based Newmark technique. After confirming the described formulation and method with previous research, different parametric samples are given to explain more about the behavior of viscoelastic nanocomposite disks that are heated quickly and rotated at a constant rate.

INVESTIGATION HFEMW ABSORPTION PROPERTIES OF POLYMER NANOCOMPOSITES BASED ON PP AND IRON NANOPARTICLES

In this work, the HFEMW absorption capacity of a nanocomposite on the basis of iron nanoparticles and polypropylene matrix was studied. The frequency of electromagnetic waves was in the range of 0.1 ÷ 3.0 GHz. Measurements were carried out depending on both the thickness of the polymer nanocomposite samples and the number of iron nanoparticles in the polymer matrix. It has been found that as the thickness of the samples increases, the electromagnetic waves absorption capacity of nanocomposite enhances. It also was investigated that HFEMW absorption capacity increases with increasing filler concentration. This increase continues up to 20% of the concentration value. With the increase of the iron nanoparticles in the polymer matrix amount of the dielectric and magnetic losses increases this, in turn, leads to the absorption of electromagnetic waves in a nanocomposite medium.

Design of dual-wideband bandstop MIM plasmonic filter using multi-circular ring resonators

A dual-wideband bandstop plasmonic filter in Near-Infrared (NIR) and Mid-Infrared (MIR) wavelength ranges based on Metal-Insulator-Metal (MIM) waveguide coupled with multi-circular ring resonators is designed. As the number of circular rings is increased, the stop wavelength bands are broadened and the extinction ratio (ER) is improved. Also, the stop wavelength ranges can be adjusted to the desired bands by changing the insulator relative permittivity. Because achieving any proper insulator relative permittivity may be difficult with the general dielectrics, the insulator region is realized by a nanocomposite medium. In this way, insulator region is designed by a polymeric medium, poly-methyl-methacrylate (PMMA), with a random distribution of spherical Ag nanoparticles. The desired relative permittivity of the insulator region and consequently, the proper stop wavelength ranges are achieved by changing the filling fraction of Ag nanoparticles. Therefore, the stop wavelength bands can be tuned with the number of circular ring resonators and guest nanoparticles filling fraction. The designed structure has potential to be employed in IR spectroscopy and broadband communications. • A dual-wideband bandstop plasmonic filter in Near-Infrared (NIR) and Mid-Infrared (MIR) wavelength ranges is designed. • As the number of circular rings is increased, the stop wavelength bands are broadened and the extinction ratio is improved. • The stop wavelength ranges can be adjusted to the desired bands by changing the insulator relative permittivity. • Insulator region is designed by a polymeric medium with a random distribution of spherical Ag nanoparticles. • The stop wavelength bands can be tuned with the number of circular ring resonators and guest nanoparticles filling fraction. The structural dimensions of the filter are considered as w = 80 nm, d = 40 nm, h = 40 nm, R in = 95 nm, R out = 150 nm and t = 55 nm.

Investigation and analysis of the optical Kerr nonlinear effect caused by metal nanocomposite on the performance of nonlinear hybrid plasmonic waveguide

In this paper, a nonlinear hybrid plasmonic waveguide (HPW) with a layer of metal-nanocomposite as nonlinear Kerr material with the high nonlinear response, long propagation length and tight light confinement for processing and active control of optical signals for nonlinear applications has been proposed. The effective parameters of the nonlinear layer due to third-order susceptibility in the HPW structure, which includes the nonlinear metal-nanocomposite layer, have been analyzed by using the Maxwell-Garnett theory. The presence of metal nanoparticles in the nanocomposite host medium improves the nonlinear effect of the proposed HPW structure. Also, the effect of radius, volume fraction, host medium permittivity related to nanoparticles and nanocomposite on the performance and output results of effective nonlinearity coefficient, propagation length, effective mode area, confinement factor has been simulated by using FEM numerical solution method in TM mode. The proposed nonlinear hybrid plasmonic waveguide is an ideal option for design and application in nonlinear all-optical integrated circuits.

Coherent control of surface plasmon polariton via spontaneously generated coherence

We investigate the control over surface plasmon polaritons (SPPs) using the interface between a four-level tripod-type atomic system and a nanocomposite medium under the effect of spontaneously generated coherence (SGC). The absorption and dispersion spectra of SPPs show interesting behavior with SGC effect at the interface. Skin depth of SPPs can be controlled via strength of SGC. The ratio of nanoparticles in the medium also affects different features of SPPs. The horizontal distances traversed by SPPs were also modified with SGC. We show the quantum confinement of SPPs at the interface for different wavelengths. These results can find important practical applications in the fields of atomic spectroscopy, plasmon-based optical devices and sensors technology.

XPS characterization of surface layers of stainless steel nitrided in electron beam plasma at low temperature

The results of the influence of low-temperature plasma nitriding at 350 °C on the CrN and FeN bonds formation of Fe-Cr-Ni austenitic steel before and after nanostructure frictional treatment are presented. The measurements of high-energy resolved X-ray photoelectron Fe 2p, Cr 2p, Ni 2p and N 1s spectra and valence bands (VB) showed that chromium and iron form CrN and FeN bonds whereas the nickel is in metallic state. It is concluded that the expanded austenite formed directly on the surface of the steel after low temperature plasma nitriding can be classified as a nanocomposite medium consisting of CrN and FeN clusters dispersed in a Fe-Cr-Ni-N matrix.

Investigation on photonic band gap of a magneto photonic crystal

Magnetic photonic crystal is a subject of extensive research for their remarkable optical and magneto optical responses. In this work a novel one dimensional magneto photonic crystal having a magnetic nanocomposite medium consists of yttrium iron garnet (YIG)and Silver which act as high refractive index layer and air as the low refractive index layer is theoretically designed. Transmission properties of the designed one dimensional photonic crystal is studied using transfer matrix method. The variation of photonic band gap (PBG) have been analysed by varying applied magnetic field, filling factor and number of layers. Appreciable changes in the photonic band gap occurs with porosity.

Forming a Nanocomposite Medium-Based Cascade Solar Cell Structure

We propose creating a solar cell on the basis of a nanocomposite medium consisting of am electrochemically fabricated porous silicon matrix with copper embedded into its pores and oxidized to Cu2O and a conductive transparent ITO film deposited by an extraction-pyrolytic method. The obtained structure with two electron–hole junctions represents, according the ratio between semiconductor band gaps, a cascade version of the solar cell with a nonconcentrated sunlight photoconversion efficiency of 7.12%.

Monomer Derived Poly(Furfuryl)/BaTiO3 0-3 Nanocomposite Capacitors: Maximization of the Effective Permittivity Through Control at the Interface.

Frequency stable, high permittivity nanocomposite capacitors produced under mild processing conditions offer an attractive replacement to MLCCs derived from conventional ceramic firing. Here, 0-3 nanocomposites were prepared using gel-collection derived barium titanate nanocrystals, suspended in a poly(furfuryl alcohol) matrix, resulting in a stable, high effective permittivity, low loss dielectric. The nanocrystals are produced at 60 °C, emerging as fully crystallized cubic BTO, 8 nm, paraelectric with a highly functional surface that enables both suspension and chemical reaction in organic solvents. The nanocrystals were suspended in furfuryl alcohol inside a uniquely prepared mold, in which volume fraction of nanocrystal filler (νf) could be varied. Polymerization of the matrix in situ at 70-90 °C resulted in a nanocomposite with a higher than anticipated effective permittivity (up to 50, with νf only 0.41, 0.5-2000 kHz), exceptional stability as a function of frequency, and very favorable dissipation factors (tan δ < 0.01, νf < 0.41; tan δ < 0.05, νf < 0.5). The increased permittivity is attributed to the covalent attachment of the poly(furfuryl alcohol) matrix to the surface of the nanocrystals, homogenizing the particle-matrix interface, limiting undercoordinated surface sites and reducing void space. XPS and FTIR confirmed strong interfacial interaction between matrix and nanocrystal surface. Effective medium approximations were used to compare this with similar nanocomposite systems. It was found that the high effective permittivity could not be attributed to the combination of two components alone, rather the creation of a hybrid nanocomposite possessing its own dielectric behavior. A nondispersive medium was selected to focus on the frequency dependent permittivity of the 8 nm barium titanate nanocrystals. Experimental corroboration with known theory is evident until a specific volume fraction (νf ≈ 0.3) where, due to a sharp increase in the effective permittivity, approximations fail to adequately describe the nanocomposite medium.

Spectral properties of nonlinear surface polaritons of mid IR range in a «semiconductor–layered metamaterial» structure

Spectral properties of surface TM-waves (polaritons) are considered in the guiding structure based on a narrow-band semiconductor (n-InSb) and a nanocomposite medium (layered metamaterial) in the mid-infrared region (5÷20 µm). The nanocomposite medium has a weak gyrotropy and contains layers of bismuth-doped iron garnet (BLIG, Lu3-xBixFe5-yGayO12) and gallium-gadolinium garnet (GGG, Gd3Ga5O12) layers magnetized to saturation. Solutions of the dispersion equations are investigated for the cases of linear and nonlinear response of the semiconductor. For an analytical description of the nonlinear response of the structure we use the «uniaxial» (longitudinal) and «biaxial» approximations. Dispersion spectra for the propagation constant, as well as field and energy characteristics of the surface polaritons are obtained and analyzed. Regions of the existence of soliton-like wave-fields of the surface polaritons are found for each of the description methods used. It is shown that the «uniaxial» model may be unsuitable for the calculation of the electromagnetic fields and energy flows in the structures based on cubic nonlinear media.

Plasmonic photo-current in freestanding monolayered gold nanoparticle membranes.

We report on photo-current generation in freestanding monolayered gold nanoparticle membranes excited by using a focused laser beam. The absence of a substrate leads to a 50% increase of the photo-current at the surface plasmon resonance. This current is attributed to a combination of trap state dynamics and bolometric effects in a nanocomposite medium yielding a temperature rise of 40 K.

Aspergilli Response to Benzalkonium Chloride and Novel-Synthesized Fullerenol/Benzalkonium Chloride Nanocomposite.

A comprehensive comparative analysis of antifungal potential of benzalkonium chloride and newly synthesized fullerenol/benzalkonium chloride nanocomposite was conducted to assess the possible impact of carbon-based nanocarrier on antimicrobial properties of the commonly used biocide. Physical characterization of synthesized nanocomposite showed zeta potential of +37.4 mV and inhomogeneous particles size distribution, with nanocomposite particles' dimensions within 30–143 nm and maximum number of particles at 44 nm. The effect of pure and fullerenol nanocarrier-bound biocide was evaluated in eight Aspergillus species. In mycelial growth assay, nanocomposite was more potent, as fungicidal effect of 1.04/0.6 μg mL−1 was obtained in all but one of the isolates (A. niger), while proportional concentration of pure biocide (0.6 μg mL−1) completely inhibited mycelial growth of only three Aspergillus species. However, conidia appear to be less susceptible to nanocomposite treatment, as lower fungistatic (MIC) and fungicidal (MFC) concentrations were obtained with biocide alone (MIC in range from 0.03 to 0.15 μg mL−1 and MFC from 0.075 to 0.45 μg mL−1). To a different degree, both substances stimulated aflatoxin B1 production and inhibited ochratoxin A synthesis. Very low mycelium biomass yield, in range from 1.0 to 3.0 mg dry weight, was documented in both biocide and nanocomposite enriched medium.

Optical spectra of nanocomposite medium and film with metal inclusions

The reflection and transmission spectra of a composite medium and a film—a dielectric matrix with spherical metal nanoinclusions—are studied. The specific features of the reflection and transmission are related to the existence of plasmon resonance and to a corresponding resonant frequency dependence of the composite medium permittivity. An oblique incidence of radiation leads to a considerable difference between the optical spectra of s- and p-polarized waves, which promises the possibility of effective control of the optical characteristics of the medium and film.

Modeling the optical properties of nanocomposite media using effective transfer matrices.

In this study we suggest an effective matrix method (EMM) for the optical modeling of nanocomposite media. We show that an effective transfer matrix of a nanocomposite medium, comprising an assumed periodic arrangement of nanoparticles embedded in a surrounding matrix, can be extracted from a rigorous finite element simulation of the structure. The effective matrix of the nanocomposite can then be used in a standard transfer matrix calculation to forward-calculate the optical spectra of arbitrary stratified structures that contain the nanocomposite. The computational complexity of this approach is significantly less than a rigorous electromagnetic simulation of such arbitrary stratified structures, while its accuracy is practically the same. We compare this EMM to various effective medium approximations based on analytical formulas and numerical retrieval techniques. We show that the proposed EMM can be successfully applied to certain nanocomposites that cannot be described with an effective refractive index.