International Journal Of Nanoscience and Nanotechnology
Volume:18 Issue: 2, Spring 2022

The effect of silica nanoparticles used as a nanoporous additive in cement was studied with various wt- % ratios. Saccharum officinarum bagasse, an agricultural waste residue was used to synthesize silica nanoparticles as it contains a high amount of silica. The synthesized silica nanoparticles were characterized through XRD and FTIR spectroscopic analysis techniques. By the analysis of XRD, crystalline peaks were found to be particularly of quartz form of silica with an average size of 25.58 nm. The characteristic functional group of the extracted silica nanoparticle was observed at various absorption bands such as the peaks at 1056 cm-1 and 794 cm-1 correspond to Si-O-Si asymmetric and Si-O symmetric stretching modes respectively. The extracted silica nanoparticles were applied to form nanocomposites with cement to investigate their compressive strength and the silica nanoparticle was found to increase the compressive strength of cement due to the pozzolanic reaction of silica nanoparticles with Ca(OH)2.

Nanotoxicology is a major field of study that exposes dangerous effects of nanomaterials on the living cells. In the present study, an extract of llex paraguarients St. Hill in distill water was firstly prepared. This extract was added to 1 mM of Cupric sulfate solution, and the change in the color of the solution from colorless to colored solution was detected. This change in color indicates that there is a formation of CuNPs. Secondly, Copper nanoparticles (CuNPs) were prepared by the chemical reduction method and characterized by the utility of different techniques such as: UV-Vis spectrometer, FTIR spectroscopy and SEM with EDAX. The evaluation of the toxicity of CuNPs was performed on human lung carcinoma cell (A549). The half-maximal inhibitory concentration IC50 of CuNPs for human lung carcinoma cell (A549) was determined. CuNPs suppressed proliferation and viability of carcinoma lung cells. Overall, the results show that the IC50's of the prepared Cu NPs were cytotoxic to cancerous lung cells.

Graphene assisted photodegradation have been used extensively as a remedial measure against pollutant dyes over last few years. The present work highlighted the comparative photodegradation effects between functionalized graphene oxide (GO) and non-functionalized graphene (Gr) maintained at room temperature (~27o C) against three different pollutant dyes viz. malachite green (MG), methylene blue (MB) and methyl orange (MO) under visible light exposure at neutral medium (pH ~ 7). The degradation of MG and MB were remarkably high upon using the functionalized GO while non-functionalized Gr had comparatively less degradation efficiency against both these dyes. On the other hand, Gr was found to be effective than GO in combatting the azoic MO dye due to poor recombination of carrier charges. The photodegradation of 1:1:1 mixture of MG:MB:MO (dye cocktail) was studied in presence of GO, separated in HPLC to estimate the degradation efficiency of each dye. The mineralized products obtained from the LC-MS/MS suggested the fragmentations in each dye occurred via demethylation route followed by asymmetric cleaving.  In real-time, the growth assessment of Lemna Minor and Eichhornia crassipes was monitored in dye cocktail alone and in presence of GO treated dye cocktail.

This study examined the preparation of composites of Bacterial Cellulose (BC) / silver nanoparticles (Ag NPs) using a substrate for the fermentation of the bacteria Gluconacetobacter xylinus C-3 and a reducing agent for the synthesis of silver nanoparticles in situ. The presence of silver in the BC/ Ag NPs composites was confirmed by various characterization tests. Thus, according to Scanning Electron Microscopy, the average size of silver was recorded at 700 nm. X-ray phase analysis showed an increase in the size of cellulose crystallites up to 122 Å with a decrease in the amount of silver nanoparticles. According to UV-visible spectroscopy, an identification peak was found between 420-580 nm. Measurements of the percentage of water absorption and the edge angles of wetting with water confirmed the structures of the resulting nanocomposites - with a smaller pore diameter and a narrow pore distribution over the film size, depending on the silver content. Using the disk diffusion method, excellent antimicrobial activity was shown with a decrease in the number of bacteria in relation to the pathogenic microorganism Staphylococcus (S.) aureus, Pseudomonas (P.) aeruginosa, Escherichia (E.) coli.

In this paper, we developed a cladding modified optical fiber to detect low concentrations of ammonia (NH3). The Modification is coating with polyaniline (PANI) nanofibers. By using single mode optical fiber (SMF), two sensors are fabricated. The first one is etched with the chemical agent which is hydrofluoric acid (HF), and the other is tapered with a glass processing workstation so that the waist diameters of 15 µm for both modified sensors. Modified fibers are spray coated. The modification done on SMFs considerably enhances the interaction between them. The proposed modification is considerably enhancing how the evanescent field and the (PANI) sensing layer interact with each other. The modified SMF sensors are subjected to NH3 with different concentrations within the visible wavelength range. The modified SMF and the nanostructured PANI films pattern results in a highly sensitive ammonia sensor at room temperature. The tapered SMF coated with PANI works better compared with the etched SMF. The results show that the response equals 89s, the recovery times equal 433s, and the sensitivity equals 139.1%. The modified fiber sensors have a limit of detection (LOD) of 0.0034% (34 ppm).

In this paper, variation of temperature and velocity profiles and the angular velocity of the nanofluid flow through triangular and rectangular baffles are investigated in the existence of a uniform magnetic field. The innovation of this paper is the investigation of nanofluid parameters passing on the different baffles on the stretching surface using the Finite Element Method. According to the results of different cases, the maximum nanofluid velocity is observed in rectangular baffles. The fluid velocity for nanofluid on the rectangular baffles is 19.5% more than on other baffles. At X=0.2 to X=0.8 for rectangular baffles and triangular baffles, the average velocity of nanofluid flow in the rectangular baffles is equal to u=0.4 but, the average velocity of nanofluid flow in the triangular baffles is u=0.04. The maximum nanofluid temperature is observed in rectangular and triangular baffles. The temperature profiles of nanofluid on the rectangular and triangular baffles are 50% more than other baffles.