Effect of electrolytes on surface tension and surface adsorption of 1-hexyl-3-methylimidazolium chloride ionic liquid in aqueous solution

Surface and bulk properties of 1-hexyl-3-methylimidazolium chloride [C₆mim][Cl] as an ionic liquid (IL) have been investigated by surface tension and electrical conductivity techniques at various temperatures. Results reveal that the ionic liquid behaves as surfactant-like and aggregates in aqueous solution. Critical aggregation concentration (cac) values obtained by conductivity and surface tension measurements are in good agreement with values found in the literature. A series of important and useful adsorption parameters including cac, surface excess concentration (Γ), and minimum surface area per molecule (A_min) at the air + water interface were estimated from surface tension in the presence and absence of different electrolytes. Obtained data show that the surface tension as well as the cac of [C₆mim][Cl] is reduced by electrolytes. Also, values of surface excess concentration (Γ) show that the IL ions in the presence of electrolyte have much larger affinity to adsorption at the surface and this affinity increased in aqueous electrolyte solution in the order of I^? > Br^? > Cl^? for counter ion of salts that was explained in terms of a larger repulsion of chloride anions from interface to the bromide and iodide anion as well as difference in their excess polarizability.     

A green and efficient oxidation of benzylic alcohols using H2O2 catalyzed by Montmorillonite-K10 supported MnCl2

<正>Primary and secondary benzylic alcohols were oxidized to the corresponding carbonyl compounds in good to high yields by environmentally friendly and green oxidant,H_2O_2 catalyzed by Montmorillonite-K10 supported manganese(Ⅱ) chloride.     

Methyl jasmonate influence on silymarin production and plant stress responses in Silybum marianum hairy root cultures in a bioreactor

In this article our aim was to evaluate mass cultivation of S. marianum hairy roots in a bioreactor to produce silymarin. The effects of methyl jasmonate (MJ) elicitation on the accumulation of silymarin and the extent of the MJ-induced oxidative damage were investigated in bioreactor hairy root cultures of S. marianum. The growth rate of the bioreactor hairy root cultures was higher than that of those in a shake flask after 3 weeks. Silymarin accumulation was increased from 0.13?mg?g?1 DW in non-treated hairy roots to 0.22?mg?g?1 DW in hairy roots 72?h after 100?μM?MJ treatment. Guaiacol peroxidase and ascorbate peroxidase were activated by MJ?72?h after treatment, being 3.2- and 1.3-fold higher, respectively, than that of the control. An increase in enzymatic activity suggests increased scavenging of reactive oxygen species, indicating the tolerance to MJ stress. These results suggest that MJ elicitation is beneficial for silymarin production using bioreactor hairy root cultures.     

Synthesis and Characterization of 8-hydroxyquinoline Complexes of Tin(IV) and Their Application in Organic Light Emitting Diode

A series of 8-hydroxyquinoline complexes of tin, Q(2)SnCl(2) (Q?=?2-methyl-8-hydroxyquinoline, 8-hydroxyquinoline, 5,7-dibromo-8-hydroxyquinoline, 5-chloro-8-hydroxyquinoline, 5,7-dichloro-8-hydroxyquinoline and 5-nitro-8-hydroxyquinoline) were prepared by reacting stannous dichloride with 8-hydroxyquinoline and its derivatives. All complexes were characterized by elemental analysis, mass spectrometry and infrared, UV-vis and (1)H NMR spectroscopes. Furthermore, the molecular structure of a representative complex, dichlorido-bis(5-nitro-quinolin-8-olato-2N,O)tin(IV), was determined by single-crystal X-ray diffraction. The photoluminescence (PL) properties of all prepared compounds and electroluminescence (EL) property of a selected complex (Q?=?5-chloro-8-hydroxyquinoline) were investigated. The results showed that the emission wavelength can be tuned by electron donating or withdrawing group substituent on 8-hydroxyquinoline. Application of prepared complexes in fabrication of an OLED has been demonstrated.     

Boundary stabilization of non-classical micro-scale beams

In this paper, the problem of boundary stabilization of a vibrating non-classical micro-scale Euler–Bernoulli beam is considered. In non-classical micro-beams, the governing Partial Differential Equation (PDE) of motion is obtained based on the non-classical continuum mechanics which introduces material length scale parameters. In this research, linear boundary control laws are constructed to stabilize the free vibration of non-classical micro-beams which its governing PDE is derived based on the modified strain gradient theory as one of the most inclusive non-classical continuum theories. Well-posedness and asymptotic stabilization of the closed loop system are investigated for both cases of complete and incomplete boundary control inputs. To illustrate the performance of the designed controllers, the closed loop PDE model of the system is simulated via Finite Element Method (FEM). To this end, new strain gradient beam element stiffness and mass matrices are derived in this work.     

Synthesis, Crystal Structure and Conformational Studies of Schiff-Base Compound 2-{[4-(Phenyldiazenyl)Phenyl]Iminomethyl}-5-Bromophenol

Abstract  

Schiff-base compound 2-{[4-(Phenyldiazenyl)phenyl]iminomethyl}-5-bromo phenol (1), containing an azo group was synthesized from the reaction of p-aminoazobenzene with 5-bromosalicylaldehyde and characterized by elemental analyses, FT-IR spectroscopy and X-ray single-crystal diffraction analysis. Molecular orbital calculation has been carried out using density functional method (B3LYP) at 6-31G basis set. Compound 1 crystallizes in the orthorhombic system, space group Pca2₁, with a = 12.1781(2) ?, b = 4.4894(10) ?, c = 27.7841(5) ?, V = 1519.02(5) ?³, and Z = 4. Compound 1 displays a trans configuration with respect to the C=N and N=N double bonds.     

Solution to system of partial fractional differential equations using the fractional exponential operators

In this article, fractional exponential operator is considered as a general approach for solving partial fractional differential equations. An integral representation for this operator is derived from the Bromwich integral for the inverse Mellin transform. Also, effectiveness of this operator for obtaining the formal solution of system of diffusion equations is discussed. Copyright © 2011 John Wiley & Sons, Ltd.     

Ab initio and semiempirical conformational and configurational analysis of N-2-(1,4-dioxane)-N’-(4-methylbenzenesulfonyl)-O-(4-methylphenoxy)isourea

The conformational, configurational behavior and the structure of N-2-(1,4-dioxane)-N’-(4-methylbenzenesulfonyl)-O-(4-methylphenoxy) isourea 1 has been studied using ab initio and semiempirical calculations (AM1 and PM3). The endo-anomeric effect and hydrogen bonds control the population of dioxane ring conformers or anomers but not the configuration interconversion of the imine of imidoyl moiety. Ab initio and AM1 and PM3 calculations demonstrate that the dioxane ring adopts a chair conformation, that the imidoyl amino group prefers an axial conformation and that the tosyl and tolyl groups about the C=N bond retain an E configuration. The computational analysis of 1 complements the X-ray findings.     

Energy dependent spin filtering by using Fano effect in open quantum rings

An open quantum ring containing magnetic quantum structures which is subjected to the Rashba spin–orbit coupling and Zeeman effect is considered. One dimensional quantum wave guide theory is developed and Transfer matrix method in conjunction with spin-dependent Griffith’s boundary condition is used to calculate the transmission coefficients of the corresponding one-electron scattering problem. Investigations into spin-dependent transport show the characteristic oscillations which are affected by impurities. The existence of Rashba spin–orbit coupling leads to the appearance of Fano resonances in transport. The results indicate that the orientation of Fano line shapes is under the influence of impurities. Also, it is shown that by using Fano resonances the system under study can be used as a cent percent spin-filtering device. The spin-filtering property of this system as a function of energy is affected by impurities and can be used in order to design optimized nanodevices.     

ANALYSIS OF THE TURBULENT BOUNDARY LAYER AND SKIN-FRICTION DRAG REDUCTION OF A FLAT PLATE BY USING THE MICRO-BLOWING TECHNIQUE

Journal of Applied Mechanics and Technical Physics - Numerical analyses of turbulent boundary layer parameters and skin-friction drag reduction on a flat plate under the effect of air micro-blowing...