In this study, we aimed to find the effect of periodic permeability on the flow dynamics of an incompressible, Newtonian, viscous and pulsatile flow of air flowing through airway generations 5–10. To solve this problem, we used a generalized Navier Stokes equation by including the Darcy law of a porous media with periodic permeability for the flow of air and Newton equation of motion for the flow of nanoparticles. The finite difference explicit numerical scheme has been carried out to solve the governing nonlinear equations and then computational work is done on MATLAB R2016 by user defined code. After performing numerical computation we found by varying mean permeability of porous media velocity of air and particle increased gradually with axial and radial distance respectively.

Liquid crystalline nanocomposites are prepared by dispersing TiO2, ZnO, Fe2O3 and Fe3O4 nanoparticles separately in 4-Cyano 4’-Propoxy-1, 1’-Biphenyl (3O-CB) liquid crystal in a 1:100 ratio. The characteristic textures exhibited are captured at different liquid crystalline phases by using POM. The phase transition temperatures are measured by both polarizing optical microscope (POM) and differential scanning calorimeter (DSC). The optical textures are analyzed by using MATLAB software to compute birefringence and order parameter of samples. The birefringence and order parameter also measured by conventional Newton’s rings technique, the results are discussed.

Multiferroic Bi1−xCexFeO3 (x = 0.05, 0.1, 0.15, 0.2) nanoparticles were prepared using an auto-combustion method. The effect of cerium substitution on the crystal structure, electrical and magnetic properties of BiFeO3 (Bismuth Ferrite) was studied. X-raydiffraction spectra revealed that Ce substitution increases the lattice parameters. The average particle size estimated from TEM images is less than 50 nanometers. According to the magnetic hysteresis loops, it was found that the enhanced magnetization which results from increasing Ce concentration is attributed to the nanoparticle size and enhanced ferroelectric polarization. The magnetization and ferroelectric polarization were found to exhibit an exotic mutual relationship. The samples were found to exhibit relaxation of dielectric polarization. This rare combination of Ce doped BiFeO3 by auto-combustion method has not been reported before.

Diamond nanoparticles containing single color centers are considered to be one of the most promising realizations of the sources of single photons required for many potential applications in quantum telecommunication and quantum computing systems. Their implementation in practical schemes, however, requires a sufficient increase in their brightness, including the enhancement of both emission and collection efficiency. In this work, we propose a design of a compact planar structure composed of a dielectric periodic cavity coupled with a strip waveguide that is particularly suitable for improving optical characteristics of color centers embedded in a nanodiamond placed inside the structure. We numerically demonstrate that such scheme permits the achievement of simultaneous increase of emission rate of color centers by ≈ 50 times in a spectral range ≈ 2 nm, and up to ≈ 85 % out-coupling efficiency of emission to the dielectric strip waveguides. We analyze the main factors that decrease the performance of the proposed arrangement and discuss the possible ways for restoring it.

In this paper, the propagation of light soliton is studied in nonlinear optical fiber. We propose the external excitation of semiconductor quantum dot (SQD) waveguides through an optical source which allows the generation of solitonic pulses. These solitonic pluses are propagated through a nonlinear optical fiber. Soliton formation is investigated by the interaction between the external optical excitation and SQDs. Here, the SQDs are considered as a quantum system of three energy levels. In this study, the Fourier Split-Step (FSS) method is used to solve the numerically continuous nonlinear Schrdinger equation (NLSE) for evolution of the soliton pulse emitted by the SQDs inside an optical fiber with real physical parameters. The effect of a SQD’s density and electric field on the pulse width is also studied. Phase plane portraits are drawn to observe the stability of soliton in fiber and SQDs.

Composite membranes based on polymer with intrinsic microporosity (PIM-1) confined in the pores of porous anodic alumina (AAO) supports were prepared by spin-coating method under vacuum suction. Water permeance of the membranes was measured at humidities ranging from 10 to 70 %. High permeance towards water vapors reaching the value of ∼ 13700 l/(m2 ·bar·h) coupled with the H2O/N2 selectivity of 1400 was observed at the humidity of 70 % for composite membranes due to the condensation in nanopores of polymer and anodic alumina channels. The obtained selectivity exceeds strongly that of bulk PIM-1 due to confinement of polymer chains mobility in AAO channels. The water vapor sorption capacity for composite membranes exceeds 7 % being governed both by condensation in polymer micropores and anodic alumina channels. Physical ageing of the membranes was monitored for a period of 6 months and then the membranes were subjected to activation in methanol. It was established that physical ageing substantially reduces the water permeance but activation in methanol allows one to partially rejuvenate water transport performance.

The combined action of ceria nanoparticles and doxorubicin on the early stages of ontogenesis of Danio rerio and Puntius tetrazona was studied. Results obtained indicate that there is a synergetic effect of CeO2 nanoparticles and doxorubicin which is demonstrated by a high incidence of embryonic malformations in fish. This synergetic effect is more pronounced in tiger barbs than in zebrafish, and depends strongly on the synthetic route of ceria nanoparticles’ preparation, the most notable effects being registered for citrate-stabilized nanoparticles.

Liquid-permeable piezoactive polyvinylidene fluoride films were produced as porous membranes using preparation process including melt extrusion, annealing, cold/hot extension and poling consequent operations. The effect of technological control parameter at extrusion stage (melt draw ratio) on the characteristics of the film structure (overall porosity, liquid permeability and polymorphous composition) was investigated. The values of melt draw ratio which provides the permeability to liquids were established. The structure elements of nano- and micro- levels were determined by a number of experimental techniques. It was proved that the samples contain the pores with sizes 10 – 50 nm. The dependence of polymorphous composition and content of piezoactive crystalline modification on preparation conditions was analyzed. Permeable polyvinylidene fluoride films were successfully poled, and the stable piezoelectric response of the samples was demonstrated.

Soft magnetic LiZnMn ferrite with low coercivity obtained via glycine-nitrate combustion was estimated in this work. According to SEM, the synthesized ceramics have a grain size ranging from 1.5 to 8 µm and the EDX, AAS and XRD data show that the obtained samples correspond to Li0.45Zn0.05Mn0.06Fe2.43O4 structure. The hysteresis loops of LiZnMn ferrite ceramics provide evidence for the magnetically soft nature of the obtained materials. Basic magnetic characteristics, including remanent magnetization, saturation magnetization, and coercive force was also described. For a sample sintered at 1000 ◦C, the values of saturation magnetization (4πMs), residual magnetization (Br) and coercive force (Hc) were 2644 G, 2139 G and 6.4 Oe, respectively, whereas the sample obtained at 1070 ◦C shows large values of saturation magnetization (3240 G) and residual magnetization (2459 G) and the coercive force is approximately half (3.4 Oe). Analysis of the influence of thermal treatment provided the possibility to determine necessary conditions for obtaining microwave ceramics based on LiZnMn ferrite via solution combustion method. Grain size distribution was examined to determine their influence on the properties of obtained ceramics.

Nanoscale systems occupy the most important place among the vehicles intended for targeted drug delivery. Such vehicles are considered in this review. Attention is paid to the nanocluster polyoxometalate-based systems which are promising for transdermal iontophoretic transport. In this relation, and due to the characteristics of the skin as a transport medium, the problems of the transfer processes modeling are considered.

This paper reports the fabrication and characterization of BaTiO3 nanofibers prepared by the electrospinning method. The X-ray diffraction (XRD) pattern revealed the formation of tetragonal phase corresponding to the Bragg angle 2θ = 31◦ and 45◦ . The formation of metal oxide is confirmed by the FTIR measurement. SEM study evidenced the smooth and randomly grown nanofibers with their average sizes 472 and 515 nm with respect to the samples BT1 and BT2 prepared at 8 and 12 kV dc voltages. TG/DTA analysis was performed to study the heating behavior of the composite BaTiO3/PVP mat and 49 % weight loss was observed at 725 ◦C.

For optical filters, TiO2 and SiO2 films are better choices due to their large refractive index contrast. In spite of the various available techniques, the sol-gel spin coating method is one of the easiest and inexpensive technique. Here, we report the experimental studies of (TiO2/SiO2)2.5 bilayer-based structures prepared with two distinct precursor concentrations. FTIR analysis showed the characteristic vibration peaks of the Ti-O-Ti and Si-O-Si bonds. XRD measurements of both the samples based on the low and high-precursor concentrations, revealed the dominant peaks of TiO2-anatase phase. FESEM study endorsed the increased thicknesses of the individual layers due to enhanced precursor concentrations. Both samples evidenced for the reflection/stop bands with 100% reflectivity. Furthermore, multilayer structure of (TiO2/SiO2)2.5 bilayers showed the corresponding shift of the reflection band from the visible-infrared wavelength region in accordance with the low-high precursor concentration. This shifting of the reflection band is attributed to the increased thicknesses of the films which is due to the enhanced grains size as confirmed by the AFM studies.

Crystalline phosphors of Eu3+-doped titania (TiO2:Eu3+) were prepared by hydro and solvothermal synthesis with luminescent ion concentration of 2 mol.%. The structure and shape of the synthesized nanoparticles were characterized using X-ray powder diffraction, transmission electron microscopy, and Raman spectroscopy. Changes in the emission, excitation spectra, and the intensity decay of the photoluminescence for TiO2:Eu3+ nanoparticles were analyzed their phase composition. The photoluminescence of synthesized TiO2:Eu3+ crystalline phosphors depends on whether the said nanophosphors are formed from organometallic or inorganic precursors under hydro- and solvothermal conditions. Indeed, photoluminescence excitation at wavelengths ranging from 350–550 nm leads to splitting of electron dipole transitions into Stark components according to the symmetry of the Eu3+ surroundings. Also, both nanoparticles with the anatase structure and phosphors predominantly containing rutile showed very short photoluminescence lifetimes.

For titanium dioxide with anatase structure doped with carbon or nitrogen, the first-principle method of projector augmented waves (PAW) is used to calculate electronic band structure, to evaluate vacancy formation energy for the oxygen sublattice, and to analyze optical absorption. It is demonstrated that the presence of carbon dopants results in the stabilization of oxygen vacancies and leads to increased absorption in the visible spectrum, which can facilitate the photocatalytic activity. The presence of nitrogen dopant also facilitates vacancy stabilization but no increase in the interband absorption is expected in the visible spectrum, i.e., the presence of nitrogen dopant cannot be considered as a factor contributing to increased photocatalytic activity. It follows from the calculated data that the maximum photocatalytic activity should be expected for the partiallyreduced anatase doped with carbon because of the absorption in the visible spectrum that combines with long time of electron-hole recombination.