Green Synthesis of CeO2 Nanoparticles from the Abelmoschus esculentus Extract: Evaluation of Antioxidant,Anticancer, Antibacterial,and Wound-Healing Activities

Metal oxide nanoparticles synthesized by the biological method represent the most recent research in nanotechnology. This study reports the rapid and ecofriendly approach for the synthesis of CeO₂ nanoparticles mediated using the Abelmoschus esculentus extract. The medicinal plant extract acts as both a reducing and stabilizing agent. The characterization of CeO₂ NPs was performed by scanning electron microscopy (SEM), X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), and Fourier transform infrared spectroscopy (FTIR). The in vitro cytotoxicity of green synthesized CeO₂ was assessed against cervical cancerous cells (HeLa). The exposure of CeO₂ to HeLa cells at 10–125 µg/mL caused a loss in cellular viability against cervical cancerous cells in a dose-dependent manner. The antibacterial activity of the CeO₂ was assessed against S. aureus and K. pneumonia. A significant improvement in wound-healing progression was observed when cerium oxide nanoparticles were incorporated into the chitosan hydrogel membrane as a wound dressing.     

Influence of laser irradiation on the optical properties of nano-sized powder of metal oxide

ZnO Nano powders were prepared by co-precipitation method which includes post-oxidation and annealing in air. Influence of laser irradiation was carried out using 355 nm laser on the physical properties of ZnO nanoparticles. SEM studies reveal agglomeration of grains resulting into enlargement and deformation of the nanoparticles. XRD pattern exhibited decrease in FWHM which is a clear evidence of the increase in crystallite size due to laser irradiation. Optical properties showed decrease in the band gap of the laser irradiated Nano powders. The observed results indicated the UV laser irradiation increases the ZnO nanoparticles crystallinity that affects the optical properties of the ZnO.     

Optimizing control of simulated moving bed separations of mixtures subject to the generalized Langmuir isotherm

Simulated moving bed (SMB) is a cost-efficient separation technique that offers high productivity and low solvent consumption. SMB has gained importance in the pharmaceutical and fine chemical industry to perform complex separation tasks. However, an open and challenging problem is the optimal, robust operation of the SMB process. We have developed a control scheme that integrates the optimization and control of the SMB unit. A significant feature of the controller is that only minimal information of the system has to be provided, i.e. the linear adsorption behavior of the mixture to be separated and the average void fraction of the columns. Therefore, a full characterization of the adsorption behavior of the mixture and the columns is no longer required. In this ‘cycle to cycle’ control scheme, the measurements, optimization and control actions are performed once in every cycle. This paper presents simulation results of the control scheme applied to the separation of binary mixtures characterized by generalized Langmuir isotherms. The results are presented and analyzed in the frame of the triangle theory that has been recently extended to encompass these types of isotherms. Besides, online optimum performance of the SMB unit is compared with off-line optimization carried out using genetic algorithm. The results show that the controller fulfills the product and process specifications while operating the SMB unit optimally, regardless of the different types of Langmuir isotherms that the systems exhibit.     

Significance of Darcy-Forchheimer Porous Medium in Nanofluid Through Carbon Nanotubes

This article manages Darcy-Forchheimer 3D flow of water based carbon nanomaterial (CNTs). A bidirectional nonlinear stretchable surface has been utilized to make the flow. Disturbance in permeable space has been represented by Darcy Forchheimer (DF) expression. Heat transfer mechanism is explored through convective heating.Outcomes for SWCNT and MWCNT have been displayed and compared. The reduction of partial differential framework into nonlinear common differential framework is made through reasonable variables. Optimal series scheme is utilized for arrangements advancement of associated flow issue. Optimal homotopic solution expressions for velocities and temperature are studied through graphs by considering various estimations of physical variables. Moreover surface drag coefficients and heat transfer rate are analyzed through plots.     

Effects of 1064 nm laser on the structural and optical properties of nanostructured TiO2 thin film

TiO₂ thin film has been widely used as photoelectrode in dye-sensitized solar cells. It can also be used in quantum dot synthesized solar cells. Study of its effects in different spectrum of light is important for its use in solar cells. We have reported effects of 1064 nm laser on the surface morphology, structural and optical properties of nanostructured TiO₂ thin film deposited on glass substrates using sol-gel spin coating technique. Q-Switched Nd:YAG pulsed laser at various power densities is used in this study. Surface morphology of the film is investigated using X-ray diffraction (XRD) and atomic force microscopy technique. The XRD pattern of as deposited TiO₂ thin film is amorphous and after laser exposure it became TiO₂ anatase structure. Atomic force microscopy of the crystalline TiO₂ thin film shows that the grain size increases by increasing laser power density. The calculations of the band gap are carried out from UV/Visible spectroscopy measurements with JASCO spectrometer. For laser power density of 25 MW/cm² there is an increase in the transmission and it decreases at the value of 38 MW/cm² and band gap decreases with increasing laser power density. Photoluminescence spectra of the crystalline TiO₂ thin film indicate two broad peaks in the range of 415 and 463 nm, one for band gap peak (415 nm) and other for oxygen defect during film deposition process.     

Optimizing control of simulated moving beds--experimental implementation

The operation of simulated moving beds (SMBs) at their optimal operating conditions is difficult and not robust. Therefore, it is common practice to operate SMB units far from their economic optimum in order to tolerate uncertainties in the system and minimize the effect of disturbances. Recently, we have proposed an on-line optimization based SMB control scheme that allows to exploit the full economic potential of SMB technology. The goal of this work is two-fold. Firstly, to experimentally evaluate and demonstrate the capability of the controller to optimize and operate the SMB units, thus delivering the products with maximum productivity and minimum solvent consumption. Secondly, to show the suitability of the controller even using a minimum of system information, thus making the detailed isotherm measurements redundant and saving time in the separation design phase. This paper reports and discusses the first experimental implementation of the control concept on a high purity separation of nucleosides (uridine, guanosine) with an eight-column four-section SMB where the species to be separated are retained on the source 30RPC stationary phase according to a linear isotherm.     

Nonlinear direct inverse method: a shortcut method for simultaneous calibration and isotherm determination

This work addresses a way to combine isotherm determination and nonlinear calibration. In this method, like the classical inverse method, experimental elution profiles are compared with the results of a detailed model that accounts for nonlinearity in equilibrium, axial dispersion, and mass transfer kinetics. However, unlike the classical inverse method, the calibration of detector is carried out simultaneously with isotherm determination thereby reducing cost and saving time. In this study no limitation is imposed on the linearity of the detector signal or on the overlapping of elution profiles for the separation of enantiomers. The method has been experimentally validated for the separation of a mixture of guaifenesin enantiomers over a wide range of concentration.     

Capacitance–voltage and conductance–voltage characteristics of Ag/n-CdO/p-Si MIS structure prepared by sol–gel method

The frequency dependent electrical properties of Ag/n-CdO/p-Si structure has been investigated using capacitance–voltage (C–V) and conductance–voltage (G/ω–V) characteristics in the frequency range 10 kHz–1 MHz in the room temperature. The increase in capacitance at lower frequencies is observed as a signature of interface states. The presence of the interfaces states (N_SS) is also evidenced as a peak in the capacitance–frequency characteristics. Furthermore, the voltage and frequency dependence of series resistance were calculated from the C–V and G/ω–V measurements and plotted as functions of voltage and frequency. The distribution profile of R_S–V gives a peak in the depletion region at low frequencies and disappears with increasing frequencies. The values of interface state densities and series resistance from capacitance–voltage-frequency (C–V-f) and conductance–voltage-frequency (G/ω–V-f) measurements were obtained in the ranges of 1.44×10¹⁶–7.59×10¹² cm^?2 eV^?1 and 341.49–8.77 Ω, respectively. The obtained results show that the C–V-f and G/ω–V-f characteristics confirm that the interface states density (N_SS) and series resistance (R_S) of the diode are important parameters that strongly influence the electrical parameters in Ag/n-CdO/p-Si structures.