Applied Nanoscience

This problem deals with the theoretical study of blood flow of nanofluid through composite stenosed arteries with permeable walls. The highly nonlinear momentum equations of nanofluid model are simplified by considering the mild stenosis case. Temperature and nanoparticle equations are coupled; so, we use homotopy perturbation method to calculate the solution of temperature and nanoparticle equations, while the exact solution has been calculated for velocity profile. Also, the expressions for flow impedance, pressure gradient and stream function are computed. These solutions depend on Brownian motion number Nb, thermophoresis number Nt, local temperature Grashof number Gr and local nanoparticle Grashof number Br. The effects of various emerging parameters are discussed through graphs for different values of interest.

Magnetite nanoparticle and graphene oxide is a promising nanoparticle that can be used in multitude of field due to their exceptional characteristic. Graphene oxide has a unique 2-D structure, and excellent chemical and physical characteristics while magnetite nanoparticle has its superparamagnetic properties which enable it to be controlled by external magnetic field. Owing to that, any new formulations of magnetic nanoparticle functionalities with graphene oxide have to be taken into consideration. In this research, magnetite nanoparticles were functionalized with graphene oxide using simple emulsion and evaporation method. All the samples were characterized by X-ray diffraction, and Fourier-transform infrared, and Raman spectroscopy. The toxicity of the nanomaterials was tested with cell viability assay (XTT) using A549 cells. The cell viability remains high within 24 h and 72 h of incubation, and when the concentration increases up to 100 µg/mL only a slight decrease of viability was observed.

Membrane technologies have become widespread due to the significant number of tasks it can solve in the treatment of drinking and waste water. Ceramic membranes have a number of advantages over polymeric membranes, but their disadvantage remains high cost. Therefore, the development of low cost ceramic membranes is essential. Low cost ceramic membranes for liquid separation were obtained from natural minerals—kaolinite and diatomaceous earth with additives of borax, soda ash, barium sulphide and manganese dioxide at different sintering temperatures. Thermal analysis with derivative thermogravimetry for all samples characterized processes of ceramic membranes models sintering and differences in curves for samples with different additives. Crystalline phases obtained in different temperature were identified by diffraction analysis. Filtering properties for samples were characterized by turbidity reduction. Dependence of filtering properties on sintering temperature and additives was shown. Additionally, difference of phase transition temperature in multicomponent aluminosilicates systems and separate components, was demonstrated. Prospects for the use of synthesized ceramic membranes for the removal of suspented particles have been shown.

The unexpected long lifetime of nanobubble against the large Laplace pressure is one of the important issues in nanobubble research and a few models have been proposed to explain it. Most studies, however, have been focused on the observation of relatively large nanobubbles over 100 nm and are limited to the equilibrium state phenomena. The study on the sub-100 nm sized nanobubble is still lacking due to the limitation of imaging methods which overcomes the optical resolution limit. Here, we demonstrate the observation of growth dynamics of 10 nm nanobubbles confined in the graphene liquid cell using transmission electron microscopy (TEM). We modified the classical diffusion theory by considering the finite size of the confined system of graphene liquid cell (GLC), successfully describing the temporal growth of nanobubble. Our study shows that the growth of nanobubble is determined by the gas oversaturation, which is affected by the size of GLC.

TiO2 has wide band gap energy and also it has fast recombination rate for electron and hole. Therefore, titanium dioxide excited by ultraviolet light and its photocatalytic activity is small. Enlargement of titanium dioxide activity can be carried out by separation of electron–hole pairs. In this, TiO2–WO3 nanocomposites with various percent of WO3 were synthesis by sol–gel technique in existence of hexadecyltrimethylammonium bromide as template. Physical, photocatalytic and structural properties of titanium dioxide and TiO2–WO3 nanocomposites were measured by many characterizations tools. Performance of titanium dioxide and TiO2–WO3 nanocomposites were measured for paracetamol degradation using visible light. Titanium dioxide band gap can be tailored by control tungsten trioxide weight percent. 3 wt% of tungsten trioxide reduce band gap to 2.63 eV. The optimum weight percent of tungsten trioxide is 3 wt% at which photocatalytic performance for paracetamol degradation is larger than that of TiO2, TiO2–WO3—1 wt%, TiO2–WO3—2 wt% and TiO2–WO3—4 wt% by 33.3, 2.1, 1.6 and 1 times, respectively. TiO2–WO3—3 wt% has photocatalytic stability for five times.

Here we present Positron Annihilation Doppler Broadening Spectroscopy (PADBS) as a powerful method to analyse the origin and development of defect processes in porous silicon structures as a result of alloying with lithium for the use in battery anode applications. Several prepared anodes were lithiated (discharged against Li+/Li) and de-lithiated (charged) with different capacities followed by a distinct treatment procedure and an analysis using the Delft Variable Energy Positron Beam. The results presented here show that we can distinguish two different processes attributed to (1) structural changes in silicon as a result of the alloying process, and (2) the formation of defects that initiate degradation of the material. The limit at which the porous material can be used for at least the first two cycles without the occurrence of damage can thus be accurately determined by using the PADBS technique.