Journal of Nano Research Vol. 63

Abstract: In this study, PbS thin films were produced at a low temperature such as 15Co using the chemical bath deposition (CBD) method.0.0085 M Pb (NO3)2 and 0.1460 M NaOH were dissolved in 100ml deionized water. 0.510 M thiourea which would be added to the solution was divided into 10 portions and added at zero, two, four, six and eight-minute intervals. Structural analysis of the obtained samples was carried out from XRD patterns which showed a significant increase in the peak intensity of the films obtained by adding thiourea at intervals of four and six minutes. The surface morphologies of the films were analyzed using a scanning electron microscope. According to the SEM images, when thiourea was added to the solution at intervals of four minutes, no cracks and holes were formed on the surfaces of the films obtained.

Abstract: A complex ZnO/ZnAl₂O₄ heterostructures thin films on glass and Si (111) substrates have been successively obtained by a soft ultrasonic spray pyrolysis (USP) method deposition using the Zn/Al molar ratios concentrations of 0.07/0.13 and 0.1/0.1, respectively. According to (XRD) an ordered zinc oxide (ZnO) and zinc aluminate (ZnAl₂O₄) structures deposited onto glass from the air annealing at 500 °C during 2 hours was observed and confirmed by the (EDX), (FTIR) and Raman spectroscopy techniques. The estimated crystallites size and stress values of ZnO and ZnAl₂O₄ in the ZnO/ZnAl₂O₄/glass film were 19 nm/0.469 GPa and 11 nm/-0.292 GPa, respectively. The lower Zn/Al molar ratio around 0.035/0.06 produced only ZnO as a single phase, suggesting the Al insufficient quantity. The Si (100) substrate with 0.07 Zn molarity conducted to the Zn₂SiO₄/ZnO/ZnAl₂O₄ composite. The Raman integrated intensity bands of ZnO and ZnAl₂O₄ increases with increasing Zn to Al molar ratio (0.1/0.1 comparatively to 0.07/0.13). The ZnO&ZnAl₂O₄ crystallinity enhances as Zn molarity increases. The ZnO films in the composites grow with (002) texture. The TC(hkl) value indicated that ZnAl₂O₄ in the ZnO/ZnAl₂O₄/glass layer is polycrystalline preferentially oriented along the (311) plane. Spinel ZnAl₂O₄ oxide onto Si (111) substrate grown according to the (220) orientation. Crystallites are larger in ZnO/ZnAl₂O₄/Si than in ZnO/ZnAl₂O₄/glass. The ZnO/ZnAl₂O₄ film onto glass substrate is transparent in the visible and near infrared regions and sensitive to UV absorption, as characterized by UV-Vis spectroscopy. The ZnO and ZnAl₂O₄ E_g values in the ZnO/ZnAl₂O₄/glass composite were 3.25 and 3.88 eV, respectively.

Abstract: This paper outlines some experimental results and discusses the new growth method for growing the different Ga_xO_y nanomaterials formed during the outward diffusion of the surface nanoclusters (SNCs) including the Au droplets and/or surface Au/Ga/O nanoclusters from the Au separated islands/strips being on GaAs substrate during the thermal Vapor -Liquid -Solid method with two steps temperature mode. Depending on the technological conditions, during the outward diffusion of the SNCs from the Au catalyst island/strip, the different sizes, morphologies and features of nanomaterials will be formed along the surface diffusion direction with the decreasing sizes. This growth method to be so called the distance directional growth method, it has not reported in the Literature. The nanomaterial growth process here could be explained by the solid - solid phase with the self-growth mechanism from the moving-diffusing SNCs with the features formed already before based on their chemical- physical interactions between the Au catalyst island/strip and GaAs substrate. In the suitable technological conditions the surface nanoscale Kirkendall effect with Kirkendall voids also completely formed... Based on the results of Field Emission Scanning electron Microscope (FESEM), the Energy-Dispersive X-ray diffraction (EDX) measurements, the formation mechanism and effect of the SNCs outward diffusion on the growth of different Ga_xO_y nanomaterials have discussed more in detailed.. The diffusivities of the SNCs depending on technological conditions in the different samples have estimated by the random walk theory, their values are in the range of 8.35x10^-10 to 10^-11 m²/sec. The distance directional growth method could be applied for the growing and controlling the nanomaterials configurations outside the Au catalyst island/strip on GaAs substrate with the different sizes for nano devices application.

Abstract: Natural clays, engineered Ag-nanoparticles (NP), TiO₂-NP, and exhausted coffee grounds were used to synthesize a nanocomposite 7NC using a Vertisol soil through a single-step by thermal method, to build a nanomaterial to degrade or filtrate pollutants from soils, water or air. The surface characteristics and the porosity of the composite were studied through nitrogen gas adsorption at liquid nitrogen temperature and application of the Brunauer–Emmett–Teller (BET) equation and the results indicated that the microporous composites ranged a surface area of 17.36 m² g^-1. X-ray diffraction showed crystalline structure and crystalline phase of the nanocomposites. HR-TEM-STEM results demonstrated that TiO₂-NP surrounded Ag-NP, and both were impregnated on natural soil nanoparticles. Oxidation states of the Ag-NP and TiO₂-NP were analyzed by X-ray photoelectron spectroscopy (XPS) The energy gap of nanocomposite 7NC was determined using the Kubelka-Munck model from Ultraviolet–visible diffuse reflectance (UV–Visible DRS) spectra. The photocatalytic activity of these nanocomposites was evaluated, and the results indicated that nanocomposite with Vertisol-soil-NP (7NC) degraded the harmful organic compound methylene blue (MB) while the antimicrobial activity and resistance against Escherichia coli and Staphylococcus aureus and the zone of inhibition (ZOI) also were analyzed. The nanocomposites Ag-NP/TiO₂-NP/natural-soil-NP/exhausted coffee-ground showed its for the development of an efficient material for environmental remediation with photocatalytic and antimicrobial activity.

Abstract: Quartzite sculptures are considered some of the most impressive and informative archaeological remains which have been found in the most of Egyptian archaeological sites. Regrettably, quartzite sculptures suffer from many deterioration aspects such as granular disintegration, scaling, cracking, efflorescence, soiling, microbiological colonization. Water is the main aggressive deterioration factor of stones and stone-based monuments, as in addition to its direct role in deterioration mechanisms, it plays as a catalyst in the physicochemical and microbiological deterioration processes.During the last two decades, polymer nanocomposites have widely been applied in the field of cultural heritage conservation due to their unique physical and chemical characteristics. Zinc oxide nanoparticles are among the most important semiconductive nanomaterials that have been applied in the fabrication of nanocomposites. They have been demonstrated to improve the physicochemical and mechanical properties of polymers. In addition, zinc oxide nanoparticles were mixed with polymers in order to fabricate superhydrophobic and self-cleaning protective materials.The aim of this paper is to evaluate the efficiency of zinc oxide nanocomposites, in order to select the best of them for the consolidation and protection of a colossal quartzite statue of Ramesses II. The properties of the treated quartzite samples were comparatively examined by colourimetric measurements, static water contact angle, compressive strength, and scanning electron microscope.

Abstract: Metal nanoparticles have become attractive as original materials for nano-inks and nano-pastes, which are used in printed electronics. Synthesizing various metal nanoparticles has been researched. We investigated the possibility of reducing metal oxide in a metal by using high-voltage pulses in this paper. This method should save electrical consumption power compared with conventional methods that use high-temperature and high-pressure plasma such as arc discharge. Reduced Al nanoparticles were obtained by applying high-voltage pulses to solutions. By analyzing elements and the composition of reduced Al nanoparticles by STEM and EDX, a large amount of reduced Al nanoparticles with diameters of a few 100 nm and thin oxide film of around 1 nm on metal surfaces were produced in experiments for reducing Al oxide. It was found from hydrogen generation using reduced Al nanoparticles by applying high-voltage pulses to solutions to evaluate reduction rate that a high reduction efficiency of 97% was obtained at maximum. We concluded that using high-voltage pulses for reduction can be suitably applied to printed electronics because the oxide film on reduced Al nanoparticles is thin. Also, because this method is similar to laser ablation in liquids using pulse lasers, the similarities were discussed in this paper.

Abstract: Superconductivity in nanostructured ceramics offers significant advantages over the conventional coarse-grained materials in view of miniaturization of superconducting electronic devices. In this paper, we report the formation of four morphologies of superconducting YBa₂Cu₃O_7-δ (YBCO) nanostructures by electrospinning technique using polymeric polyvinyl pyrrolidone (PVP) solutions of different molecular weight and altering the total content of the metallic precursors. The morphologies prepared using this strategy are nanorods (NRs), nanogarlands (NGs), nanohierarchical (NH), and nanoparticles (NPs). Alternating current susceptibility measurements showed high critical temperatures (T_C ~90 K) for the NH YBCO synthesized using PVP of the lowest molecular weight; whereas the YBCO NRs synthesized using a higher molecular weight polymer showed the lowest T_C (82 K). A relationship between the particulate properties and T_C was also observed – the lower is the pore size the higher is the T_C. The YBCO NGs showed the highest specific surface area (7.06 m²/g) with intermediate T_C (88 K). Electrospinning process appears an effective and controllable technique to produce different nanomorphologies with intrinsic properties suitable for practical applications.

Abstract: In this experimental work, Magneto rheological abrasive flow nano finishing processes were conducted on AISI Stainless steel 316L work pieces that are widely used in medical implants. The focus of the present study is to assess the effect of input variables namely the volume percentage of iron (Fe) particles, silicon carbide (SiC) abrasive particles in the Magneto rheological abrasive fluid and number of cycles on the final surface roughness at nano level as well as the material removal rate. The volume % of Fe particles were taken as 20, 25 and 30 and the volume % of SiC particles were taken as 10, 15 and 20. The different number of cycles considered for the study is 100,200 and 300. There are 20 different set of experiments with different combinations of input variables mentioned have been carried out based on the experimental design derived through central composite design technique. The minimum surface roughness observed is 23.34 nanometer (nm) from the initial surface roughness of 1.92 micro meter (µm). Towards optimizing the input process variables, a multi objective optimization was carried out by using response surface methodology.

Abstract: The dynamic free and forced axial vibrations subjected to moving exponential and harmonic axial forces of a single-walled carbon nanotube (SWCNT) embedded in an elastic medium, are studied in this paper. Two different boundary conditions of SWCNT, including clamped-clamped and clamped-free, are taken into account. Eringen’s nonlocal elasticity theory is used to show the nonlocality for the model. The constitutive equations and their boundary conditions are derived by Hamilton’s principle. Employing the general solution, the derived equations are analytically solved to obtain two items. Firstly, the axial natural frequencies, secondly, the time-domain axial displacements at the middle of the carbon nanotube (CNT), and then the maximum axial displacements. The responses are validated with previous works, and the results demonstrates good agreement to them to verify the influence of the nonlocal parameter on the nondimensional natural frequencies for three various mode numbers. In the time-domain section, the effects of the nonlocal parameter, length, nondimensional stiffness of the elastic medium, and velocity of the moving load on the axial displacement are investigated. Also, the influences of the excitation frequency to natural frequency for the harmonic moving load, as well as the time constant for the exponential moving load on the axial displacement, are illustrated. Finally, the effect of the nonlocal parameter on the maximum axial deflection versus velocity parameter is schematically indicated.

Abstract: In this paper, the digital and analog performance for Double Material Gate Surrounding Gate Metal Oxide Semiconductor Field Effect Transistor (DM SG MOSFET) has been analyzed. A detailed study of DM SG MOSFET is performed for different channel length ratio's. The comparison analysis on surface potential, electric field, transfer characteristics, output characteristics, transconductance and output conductance is carried with respect to the silicon dioxide and hafnium dioxide based device. It has been found from the simulation results that HfO₂ dielectric used DM SG TFET provides better performance than SiO₂ dielectric used DM SG TFET. Also it has been observed from the presented results that the transconductance is 45.32 at 1:3 channel length ratio for DG SG MOSFET.