Rapid Biological Synthesis of Silver Nanoparticles from Ocimum sanctum and Their Characterization

With development of nanotechnology, the biological synthesis process deals with the synthesis, characterization, and manipulation of materials and further development at nanoscale which is the most cost-effective and eco-friendly and rapid synthesis process as compared to physical and chemical process. In this research silver nanoparticles (AgNPs) were synthesized from silver nitrate (AgNO3) aqueous solution through eco-friendly plant leaf broth of Ocimum sanctum as reactant as well as capping agent and stabilizer. The formation of AgNPs was monitored by ultraviolet-visible spectrometer (UV-vis) and Fourier transform infrared (FTIR) spectroscopy. X-ray diffraction (XRD) and scanning electronic microscopy (SEM) have been used to characterize the morphology of prepared AgNPs. The peaks in XRD pattern are in good agreement with that of face-centered-cubic (FCC) form of metallic silver. Thermal gravimetric analysis/differential thermal analysis (TGA/DTA) results confirmed the weight loss and the exothermic reaction due to desorption of chemisorbed water. The average grain size of silver nanoparticles is found to be 29 nm. The FTIR results indicated that the leaf broths containing the carboxyl, hydroxyl, and amine groups are mainly involved in fabrication of silver AgNPs and proteins, which have amine groups responsible for stabilizing AgNPs in the solution.

Spreadability of Ag Layer on Oxides and High Performance of AZO/Ag/AZO Sandwiched Transparent Conductive Film

Single layers of indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), and Ag, bilayers of ITO/Ag and AZO/Ag, and sandwiched layers of ITO/Ag/ITO (IAI) and AZO/Ag/AZO (ZAZ) were fabricated on ordinary glass substrates using magnetron sputtering. The surface morphologies of single layers and bilayers were measured. The sheet resistance and transmittance of the sandwiched layers were investigated. The results showed that the spreadability of the Ag on the AZO was significantly better than that on the ITO or bare glass substrate. The spreadability of Ag on underlayers influences obviously the performance of transparent conductive oxide/Ag/transparent conductive oxides (TCO/Ag/TCO or TAT). The sheet resistance and transmittance of the ZAZ sandwiched layer with the matching of 35 nm AZO (35 nm)/Ag (9 nm)/AZO (35 nm) fabricated in this paper were low to 3.84 Ω/sq and up to 85.55% at 550 nm, respectively. Its maximum Haacke figure of merit was 0.05469 Ω−1, higher than that of IAI multilayer.

A Review of Current Research into the Biogenic Synthesis of Metal and Metal Oxide Nanoparticles via Marine Algae and Seagrasses

Today there is a growing need to develop reliable, sustainable, and ecofriendly protocols for manufacturing a wide range of metal and metal oxide nanoparticles. The biogenic synthesis of nanoparticles via nanobiotechnology based techniques has the potential to deliver clean manufacturing technologies. These new clean technologies can significantly reduce environmental contamination and decease the hazards to human health resulting from the use of toxic chemicals and solvents currently used in conventional industrial fabrication processes. The largely unexplored marine environment that covers approximately 70% of the earth’s surface is home to many naturally occurring and renewable marine plants. The present review summarizes current research into the biogenic synthesis of metal and metal oxide nanoparticles via marine algae (commonly known as seaweeds) and seagrasses. Both groups of marine plants contain a wide variety of biologically active compounds and secondary metabolites that enables these plants to act as biological factories for the manufacture of metal and metal oxide nanoparticles.

Synthesis and Characterization of Zinc Oxide and Iron Oxide Nanoparticles Using Sesbania grandiflora Leaf Extract as Reducing Agent

The objectives of this present study are to synthesize iron oxide and zinc oxide nanoparticles from different concentrations of Sesbania grandiflora leaf extract (5–20%) using zinc nitrate and ferrous chloride as precursor materials and synthesized nanoparticles were characterized using UV-visible spectrometer, FTIR, X-ray diffraction, and SEM. The results showed that synthesized zinc oxide and iron oxide nanoparticles exhibited UV-visible absorption peaks at 235 nm and 220 nm, respectively, which indicated that both nanoparticles were photosensitive and the XRD study confirmed that both nanoparticles were crystalline in nature. In addition, FTIR was also used to analyze the various functional groups present in the synthesized nanoparticles. The SEM results reveal that zinc oxide nanoparticles were spherical in shape and having the particle size range of 15 to 35 nm whereas the iron oxide nanoparticles were nonspherical in shape with the size range of 25 to 60 nm. Application of synthesized nanoparticle on seafood effluent treatment was studied.

Heat and Mass Transfer on Squeezing Unsteady MHD Nanofluid Flow between Parallel Plates with Slip Velocity Effect

Heat and mass transfer behavior of unsteady flow of squeezing nanofluids between two parallel plates in the sight of uniform magnetic field with slip velocity effect is investigated. The governing equations representing fluid flow have been transformed into nonlinear ordinary differential equations using similarity transformation. The equations thus obtained have been solved numerically using Runge-Kutta-Fehlberg method with shooting technique. Effects on the behavior of velocity, temperature, and concentration for various values of relevant parameters are illustrated graphically. The skin-friction coefficient and heat and mass transfer rate are also tabulated for various governing parameters. The results indicate that, for nanofluid flow, the rates of heat and mass transfer are inversely proportional to nanoparticle volume fraction and magnetic parameter. The rate of mass transfer increases with increasing values of Schmidt number and squeeze number.

On Molecular Topological Properties of TiO2 Nanotubes

Titania nanotube is a well-known semiconductor and has numerous technological applications. In chemical graph theory, topological indices provide an important tool to quantify the molecular structure and it is found that there is a strong correlation between the properties of chemical compounds and their molecular structure. Among different topological indices, degree-based topological indices are most studied and have some important applications. In this study, several old and new degree-based topological indices have been investigated for titania TiO2 nanotubes.

Plasmachemical Synthesis of Nanopowders in the System Ti(O,C,N) for Material Structure Modification

Refractory nanoparticles are finding broad application in manufacturing of materials with enhanced physical properties. Production of carbide, nitride, and carbonitride nanopowders in high volumes is possible in the multijet plasmachemical reactor, where temperature and velocity distributions in reaction zone can be controlled by plasma jet collision angle and mixing chamber geometry. A chemical reactor with three Direct Current (DC) arc plasma jets intersecting at one point was applied for titanium carbonitride synthesis from titanium dioxide, propane-butane mixture, and nitrogen. The influence of process operational parameters on the product chemical and phase composition was investigated. Mixing conditions in the plasma jet collision zone, particles residence time, and temperatures were evaluated with the help of Computational Fluid Dynamics (CFD) simulations. The synthesized nanoparticles have predominantly cubic shape and dimensions in the range 10–200 nm. Phase compositions were represented by oxycarbonitride phases. The amount of free (not chemically bonded) carbon in the product varied in the range 3–12% mass, depending on synthesis conditions.

One-Pot Fabrication and Characterization of Silver Nanoparticles Using Solanum lycopersicum: An Eco-Friendly and Potent Control Tool against Rose Aphid, Macrosiphum rosae

The espousal of nanotechnology is a current come-up of the present revolution. As we know that the rose aphid, Macrosiphum rosae (Hemiptera: Aphididae), is a key pest on rose plant in Kashmir Valley, India, it exhibits a worldwide distribution. In the present study, we have synthesized biologically silver nanoparticles (Ag NPs) from Solanum lycopersicum and characterized them by UV-vis spectroscopy, TEM, and X-RD analysis. The experiment was performed by leaf dip method. Insecticidal solutions of different Ag NPs concentrations, namely, 200, 300, 400, and 500 ppm, were tested on M. rosae. For assessment purposes, leaves were treated with distilled water (used as control). Aphid mortality data revealed that the Ag NPs were effective at 500 ppm concentration. As the concentration and day’s treatment increased, the aphid mortality rate also increased. There were statistically significant differences in M. rosae mortality between concentrations by LSD at 5%. In wrapping up, the use of Ag NPs in pest control processes will be the most novel eco-friendly approach in the Kashmir Valley, India, in future.

In Vitro Cytotoxicity of Nanoparticles: A Comparison between Particle Size and Cell Type

The reduction in size of Zinc oxide (ZnO) and Silicon dioxide (SiO2) particles from micron to nano scale offers unique physical characteristics on one hand while making them cytotoxic on other hand. The present study was aimed at comparing cytotoxic effects of ZnO and SiO2 nanoparticles with their micron size and secondary aim was to compare responses of these particles to two different cell types, namely, human lung epithelial cells (L-132) and human monocytes (THP-1). The L-132 and THP-1 cells were exposed to nano and micron size of ZnO and SiO2 particles with different concentrations (5–500 μg/mL) for 24 h, and cytotoxicity was analyzed by MTT assay, live-dead staining, and TC-50 was calculated. ZnO and SiO2 particles showed concentration-dependent cytotoxicity in both cell lines. In size-dependent study, ZnO particles exhibited nearly equal toxicity profile in L-132 cells while in THP-1 cells nano ZnO showed more toxicity than its micron size. The SiO2 particles showed more toxicity in their nano size than micron size in both cell lines. Human monocytes, THP-1 cells, were more sensitive towards the toxicity of both particles than human lung cells, L-132. The results highlight the difference of cytotoxicity between particle sizes and differential sensitivity of cells towards the particles of same composition. In conclusion, ZnO and SiO2 particles exhibited concentration-dependent toxicity, which was more in their nano size than micron counterpart. However, the toxic response varies depending on type of cell exposed due to differential sensitivity.

Demonstration of Ultra-Fast Switching in Nanometallic Resistive Switching Memory Devices

Interdependency of switching voltage and time creates a dilemma/obstacle for most resistive switching memories, which indicates low switching voltage and ultra-fast switching time cannot be simultaneously achieved. In this paper, an ultra-fast (sub-100 ns) yet low switching voltage resistive switching memory device (“nanometallic ReRAM”) was demonstrated. Experimental switching voltage is found independent of pulse width (intrinsic device property) when the pulse is long but shows abrupt time dependence (“cliff”) as pulse width approaches characteristic RC time of memory device (extrinsic device property). Both experiment and simulation show that the onset of cliff behavior is dependent on physical device size and parasitic resistance, which is expected to diminish as technology nodes shrink down. We believe this study provides solid evidence that nanometallic resistive switching memory can be reliably operated at low voltage and ultra-fast regime, thus beneficial to future memory technology.