Effect of BaTiO₃Nanoparticle on Electro-Optical Properties of Polymer Dispersed Liquid Crystal Displays

Ferro nematic suspensions are the prominent materials to enhance the electro optical performance of liquid crystal displays. Electro optical properties of polymer dispersed liquid crystal (PDLC) display with the introduction of Barium Titanate nanoparticles have been investigated in this article and it is shown that there is a considerable enhancement in electro-optical response of the displays. The nanoparticles lower the switch-on electric field and thereby increase the optical transmission at certain voltages of the displays. The electro-optical characteristics of the PDLC cells were investigated with a He-Ne laser followed by MatLab calculations.

Synthesis,optimization and characterization of biochar based catalyst from sawdust for simultaneous esterification and transesterification

The development of a benign environmental catalyst for the generation of biodiesel is an area of importance to reduce the overall usage of fossil fuels. In the current work, biochar was produced by slow pyrolysis of Irul wood sawdust. The optimization for biochar generation was carried out for different reaction temperatures and heating durations. The biochar was used to prepare solid acid catalysts by sulfonation process. The characterization of biochar and the sulfonated catalyst were carried out using Elemental analysis, Fourier Transform Infrared spectroscopy(FTIR), Powder X-ray Diffraction(XRD), Thermo Gravimetric Analysis(TGA), Scanning Electron Microscopy(SEM) and Surface area analyzer(BET). The characterization results showed that sulfonation of biochar resulted in biochar based solid acid catalyst containing various functional acidic groups like weak acidic\\OH groups, strong acidic\\COOH and SO3 H groups. The total acid density and sulfonic acid group density of catalyst were estimated and showed excellent acidic sites concentration which gives a good catalytic activity for biodiesel production through simultaneous esterification and transesterification. The enhanced catalytic activity is due to the high acid density of SO3 H groups and the reactant accessibility towards acidic sites as well as the strong affinity between the hydrophilic reactants and the neutral OH groups which are bonded with the polycyclic aromatic carbon rings. The performance of biochar catalyst for the production of biodiesel was evaluated by comparing the yield obtained. The FTIR and Gas Chromatography–Mass Spectroscopy(GC–MS) were also carried out for the analysis of biodiesel produced.

Fe3O4 nanoparticles impregnated eggshell as a novel catalyst for enhanced biodiesel production

Biodiesel is a green fuel which can replace diesel while addressing various issues such as scarcity of hydrocarbon fuels and environmental pollution to an extent. The high production cost of biodiesel and the recovery of the catalyst after the transesterification process are the major challenges to be addressed in biodiesel production. In the present work, a cheap and promising solid base oxide catalyst was synthesized from chicken eggshell by calcination at 900 ℃ forming catalyst eggshells(CES) and was impregnated with the nanomagnetic material(Fe3O4) to obtain Fe3O4 loaded catalytic eggshell(CES–Fe3O4). Fe3O4 nanomaterials were synthesized by co-precipitation method and were loaded in catalytic eggshell by sonication, for better recovery of the catalyst after transesterification process. CES–Fe3O4 material was characterized by Thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy, a vibrating-sample magnetometer, Brunauer-Emmett-Teller, Dynamic light scattering, and Scanning electron microscopy. Biodiesel was synthesized by transesterification of Pongamia pinnata raw oil with 1:12 oil to methanol molar ratio and 2 wt% catalyst loading for 2 h at a temperature of 65 ℃ and yields were compared. The reusability of the catalyst was studied by the transesterification of the raw oil and its catalytic activity was found to be retained up to 7 cycles with a yield of 98%.

Uptake and Intracellular Fate of Fluorophore Labeled Metal−Organic-Framework(MOF)Nanoparticles

The uptake and the fate of Zr-based metal−organic-framework nanoparticles labeled with organic fluorophores in HeLa cells has been monitored with fluorescence detection and elemental analysis.The nanoparticles have been selected as a model system of carrier nanoparticles(here Zr-based metal−organic-framework nanoparticles)with integrated cargo molecules(here organic fluorophores),with aze that does not allow for efficient exocytosis,a material which only partly degrades under acidic conditions as present in endosomes/lysosomes,and with limited colloidal stability.Data show that,for Zr-based metal−organic-framework nanoparticles of 40 nm size as investigated here,the number of nanoparticles per cells decreases faster due to particle redistribution upon proliferation than due to nanoparticle exocytosis and that,thus,also for this system,exocytosis is not an efficient pathway for clearance of the nanoparticles from the cells.

Surface-engineered gadolinium oxide nanorods and nanocuboids for bioimaging

Folic acid and D-gluconic acid-capped gadolinium oxide nanorods and nanocuboids were synthesized via co-precipitation method.Comparative study of relaxivity factor on the role of capping and morphology for enhancing contrast ability for T_(1) and T_(2) magnetic resonance imaging(MRI) was investigated.The obtained r_(2)/r_(1) ratio for folic acid and D-gluconic acid-capped gadolinium oxide nanorods and nanocuboids was 1.5 and 1.3,respectively.The nanocrystals were characterized and presented with properties such as good dispersity and stability required for standard contrast agent used in MRI.The characterization and the analysis of capping agent for nanocrystals suggest the preferable use of carbohydrate moieties with higher number of hydroxyl functional group reacted with urea and hydrogen peroxide for desired morphology and anisotropic growth.Thermogravimetric-differential thermal analysis(TG-DTA) illustrated the amount of capping,transition temperature from Gd(OH)3 to GdOOH and crystallization temperature from GdOOH to Gd2O3.These nanocrystals would be significant for other biomedical applications such as drug delivery when equipped with well-functionalized drug molecules.

Stability of passive film and antibacterial durability of Cu-bearing L605 alloy in simulated physiological solutions

In this work,the stability of passive film for long-time immersed Cu-bearing L605(L605-Cu) alloy in the phosphate buffer solution(PBS) was studied by potentiodynamic polarization and electrochemical impedance spectroscopy.The results showed that the impedance of passive film for L605-Cu alloy experienced an initial increase and subsequent stabilization with the increase in the immersion time.In addition,the plate count method was employed to assess the antibacterial durability of L605-Cu alloy against Escherichia coli after long-time immersion.The results indicated that the antibacterial rate of L605-Cu alloy presented a declining tendency with the immersion time prolonging.X-ray photoelectron spectroscopy(XPS) was used to analyze the change of the chemical composition in the passive film on L605-Cu alloy immersed in the PBS for different time.The results showed that Cu content and its compounds in the passive film gradually increased with the immersion time prolonging,hinting declined activity of Cu ions penetrating into the passive film,which resulted in a decrease in the antibacterial performance.

Ion separation and water purification by applying external electric field on porous graphene membrane

Using molecular dynamics （MD） simulations, a porous graphene membrane was exposed to external electric fields to separate positive and negative ions from salt-water and to produce fresh water. It was observed that, by increasing the strength of the applied electric field, ion separation improved noticeably. In addition, to obtain fresh water, the designed system included two graphene membranes, which are exposed to two external electric fields in opposite directions. Ion rejection was found to be greater than 93% for the electric field of 10 mV/A and higher. This atomic-level simulation increases the understanding of electric field effects on desalination using multilayer graphene membranes and can be helpful in designing more efficient membranes.