Hybrid Isothermal Model for the Ferrohydrodynamic Chemically Reactive Species

A hybrid isothermal model for the homogeneous-heterogeneous reactions in ferrohydrodynamic boundary layer flow is established. The characteristics of Newtonian heating and magnetic dipole in a ferrofluid due to a stretchable surface is analyzed for three chemical species. It is presumed that the isothermal cubic autocatalator kinetic gives the homogeneous reaction and the first order kinetics gives the heterogeneous (surface) reaction. The analysis is carried out for equal diffusion coefficients of all autocatalyst and reactions. Heat flux is examined by incorporating Fourier's law of heat conduction. Characteristics of materialized parameters on the magneto-thermomechanical coupling in the flow of a chemically reactive species are investigated. Further, the heat transfer rate and friction drag are depicted for the ferrohydrodynamic chemically reactive species. It is evident that the Schmidt number has increasing behavior on the rate of heat transfer in the boundary layer. Comparison with available results for specific cases is found an excellent agreement.     

Utilization of saffron (<Emphasis Type="Italic">Crocus sativus L.</Emphasis>) as sensitizer in dye-sensitized solar cells (DSSCs)

Photoelectrodes of dye-sensitized solar cells (DSSCs) have been prepared using nanosized titanium dioxide that have soaked in a solution of different saffron (Crocus sativus L.) spice content in ethanol. The optimized polyacrylonitrile (PAN)-based gel polymer electrolyte with 40.93 wt.% ethylene carbonate, 37.97 wt.% propylene carbonate, 4.37 wt.% tetrapropylammonium iodide, 9.86 wt.% PAN, 1.24 wt.% 1-butyl-3-methylimidazolium iodide, 4.35 wt.% lithium iodide and 1.28 wt.% iodine has been used as the electrolyte for DSSC. The electrolyte has conductivity of 2.91 mS cm^?1 at room temperature (298 K). DSSCs were also sensitized with saffron solution that has been added with 30 wt.% chenodeoxycholic acid (CDCA) co-adsorbent and designated as DSSC P4. The solar cell converts light-to-electricity at an efficiency of 0.31%. This is 29% enhancement in efficiency for the DSSC without addition of CDCA in the saffron-ethanol solution. The DSSC exhibits current density at short-circuit (J _sc ) of 1.26 mA cm^?2, voltage at open circuit (V _oc ) of 0.48 V and 51% fill factor. DSSC P4 also exhibits the highest incident photon-to-current density of more than 40% at 340 nm wavelength.     

A green synthetic approach toward the synthesis of structurally diverse spirooxindole derivative libraries under catalyst-free conditions

A catalyst-free green methodology for the synthesis of pharmacologically important spirooxindole derivatives has been developed by a three-component domino reaction between isatin, various amino compounds, and 1,3-dicarbonyl or 3-phenylisoxazolone compounds in ethyl l-lactate medium at room temperature. This new efficient synthetic method facilitated the formation of a wide range of biologically significant spirooxindole derivatives (including 17 new spirooxindoles) under very mild conditions. The cytotoxic activity of one of the isoxazole-fused spirooxindoles was evaluated in MDA-MB 468 breast cancer cell line. It was found that cell survivability decreases with increasing concentration of the selected compound in MDA-MB 468 breast cancer cells.     

Application of Artificial Neural Network for Yield Prediction of Lipase-Catalyzed Synthesis of Dioctyl Adipate

In this study, an artificial neural network (ANN) trained by backpropagation algorithm, Levenberg–Marquadart, was applied to predict the yield of enzymatic synthesis of dioctyl adipate. Immobilized Candida antarctica lipase B was used as a biocatalyst for the reaction. Temperature, time, amount of enzyme, and substrate molar ratio were the four input variables. After evaluating various ANN configurations, the best network was composed of seven hidden nodes using a hyperbolic tangent sigmoid transfer function. The correlation coefficient (R ²) and mean absolute error (MAE) values between the actual and predicted responses were determined as 0.9998 and 0.0966 for training set and 0.9241 and 1.9439 for validating dataset. A simulation test with a testing dataset showed that the MAE was low and R ² was close to 1. These results imply the good generalization of the developed model and its capability to predict the reaction yield. Comparison of the performance of radial basis network with the developed models showed that radial basis function was more accurate but its performance was poor when tested with unseen data. In further part of the study, the feedforward backpropagation model was used for prediction of the ester yield within the given range of the main parameters.     

Synthesis, crystal structure and in vitro antitumor activity of carboxylate bridged dinuclear organotin(IV) complexes

Two novel dinuclear organotin(IV) complexes [n-Bu₂Sn(imda)(H₂O)]₂·Bipy (1) and [n-Bu₂Sn(imda)(H₂O)]₂·Phen (2) [H₂imda = iminodiacetic acid, Bipy = 2,2′-bipyridine and Phen = 1,10-phenanthroline] were synthesised and characterized employing IR, ¹H, ¹³C, ¹¹⁹Sn NMR, and ¹¹⁹Sn Mössbauer spectroscopic and elemental analyses. Single crystal X-ray crystallography of 1 has confirmed that it is a binuclear Sn(IV) species formed via carboxylate bridges where each metal adopted a seven coordinate distorted pentagonal bipyramidal geometry. The iminodiacetate dianion (imda²⁻) acts as a potential tridentate [N,O,O] carboxylate bridging ligand. The packing revealed that the additional α-diimine (Bipy or Phen) does not coordinate to metal ion. However, its presence in the crystal lattice as spacer helps for the formation of a supramolecular framework by bringing the two binuclear species close enough through extensive H-bonding. The in vitro cytotoxicity of compounds 1 and 2 indicate better results than cisplatin against three tumor cell lines investigated.     

Projection algorithms for solving a system of general variational inequalities

In this paper, we introduce and consider a new system of general variational inequalities involving four different operators. Using the projection operator technique, we suggest and analyze some new explicit iterative methods for this system of variational inequalities. We also study the convergence analysis of the new iterative method under certain mild conditions. Since this new system includes the system of variational inequalities involving three operators, variational inequalities and related optimization problems as special cases, results obtained in this paper continue to hold for these problems. Our results can be viewed as a refinement and improvement of the previously known results for variational inequalities.     

On k-uniformly close-to-convex functions of complex order

In this paper, we define and study some subclasses of analytic functions by using fractional derivative operator. Some interesting properties, coefficients problems and inclusion results of these classes are investigated. It is also shown that these classes are closed under convolution with convex functions and some applications are given.     

Implicit Iterative Methods for Nonconvex Variational Inequalities

In this paper, we suggest and analyze an implicit iterative method for solving nonconvex variational inequalities using the technique of the projection operator. We also discuss the convergence of the iterative method under suitable weaker conditions. Our method of proof is very simple as compared with other techniques.     

Mixed quasi complementarity problems in topological vector spaces

In this paper, we introduce and consider a new class of complementarity problems, which is called the mixed quasi complementarity problems in a topological vector space. We show that the mixed quasi complementarity problems are equivalent to the mixed quasi variational inequalities. Using the KKM mapping theorem, we study the existence of a solution of the mixed quasi variational inequalities and mixed quasi complementarity problems. Several special cases are also discussed. Results obtained in this paper can be viewed as extension and generalization of the previously known results.     

Spherical indentation analysis of stress relaxation for thin film viscoelastic materials

The mechanical testing of thin layers of soft materials is an important but difficult task. Spherical indentation provides a convenient method to ascertain material properties whilst minimising damage to the material by allowing testing to take place in situ. However, measurement of the viscoelastic properties of these soft materials is hindered by the absence of a convenient yet accurate model which takes into account the thickness of the material and the effects of the underlying substrate. To this end, the spherical indentation of a thin layer of viscoelastic solid material is analysed. It is assumed that the transient mechanical properties of the material can be described by the generalised standard linear solid model. This model is incorporated into the theory and then solved for the special case of a stress relaxation experiment taking into account the finite ramp time experienced in real experiments. An expression for the force as a function of the viscoelastic properties, layer thickness and indentation depth is given. The theory is then fitted to experimental data for the spherical indentation of poly(dimethyl)siloxane mixed with its curing agent to the ratios of 5:1, 10:1 and 20:1 in order to ascertain its transient shear moduli and relaxation time constants. It is shown that the theory correctly accounts for the effect of the underlying substrate and allows for the accurate measurement of the viscoelastic properties of thin layers of soft materials.