Structural,Optical, and Magnetic Properties of Mn-Doped Nickel Ferrite (Ni1-xMnxFe2O4) Thin Films Deposited by Jet Nebulizer Spray Pyrolysis Technique

Journal of Superconductivity and Novel Magnetism - In this work, pure and Mn-doped nickel ferrite (Ni1-xMnxFe2O4, x?=?0, 3, 6, 9, and 12 wt%) thin films were prepared using facile...     

Optimal design of savonius wind turbines using ensemble of surrogates and CFD analysis

Structural and Multidisciplinary Optimization - Current study presents fluid flow analysis using CFD and a surrogate based framework for design optimization of Savonius wind turbines. The CFD model...     

Timbre features with MEDIAN values for compensating intra-speaker variability in speaker identification of whispering sound

International Journal of Speech Technology - Because voiced phonations are absent in the whisper, distinguishing among the speakers with whispered voice is a difficult task. The selection...     

Aromatic polyesters containing pendent 4-(phenylsulfonyl)phenyl groups: synthesis and characterization

A new bisphenol, 1,1-bis-[(4-hydroxyphenyl)-1-(4-phenylsulfonyl)phenyl)]ethane (DPSBP) was synthesized starting from diphenylsulfide and was characterized by spectroscopic methods. DPSBP was polycondensed with isophthalic acid chloride (IPC), terephthalic acid chloride (TPC) and a mixture of IPC and TPC (50:50 mol%) by phase-transfer catalysed interfacial polymerization method to obtain aromatic polyesters containing pendent 4-(phenylsulfonyl)phenyl groups. A series of copolyesters was also obtained by polycondensation of varying molar proportions of DPSBP and bisphenol-A (BPA) with TPC. (Co)polyesters exhibited inherent viscosities in the range 0.56–1.57 dLg^?1 and number average molecular weights (Mn) were in the range 28,650–80,230 g/mol. Polyesters dissolved readily in common organic solvents such as dichloromethane, chloroform, tetrahydrofuran and aprotic polar solvents such as N-methylpyrrolidone, and N,N-dimethylacetamide. Tough, transparent and flexible films of polyesters could be cast from their chloroform solutions. X-Ray diffraction studies indicated amorphous nature of aromatic polyesters. Polyesters showed T_g values in the range 223–257 °C while T₁₀ values were in the range of 469–484 °C indicating their excellent thermal stability.     

Effect of iron oxide (Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>) on the structural,optical, electrical,and dielectric properties of SrO–V<Subscript>2</Subscript>O<Subscript>5</Subscript> glasses

The oxide glass system of the composition (10 – x)SrO–xFe₂O₃–90V₂O₅, (x = 0, 2, 4, 6 and 8 mol %) were prepared by a standard melt quenching technique. The amorphous nature of the prepared glass was confirmed using X-ray diffraction technique. The infrared spectra of these glasses were recorded over a continuous spectral range (850–1500 cm^–1). The density of prepared sample was obtained by the Archimedes principle. The physical parameters of the glasses were also determined with respect to the composition. Density increases from 3.10 to 3.20 g/cm³, whereas the molar volume decreases with the increase in Fe₂O₃ concentration. In order to study optical properties, absorption spectra were measured at room temperature. Indirect optical energy band gap, optical dielectric constant, refractive index were calculated from optical energy band gap. The refractive index decreases gradually with the increase in Fe₂O₃ content due to increase of bridging oxygen’s. For temperatures from 300 to 500 K, the dc conductivity increased with the increasing Fe₂O₃ content. The dielectric properties like dielectric constant, dielectric loss factor and dielectric loss tangent investigated at the room temperature in the frequency range of 10 kHz to 1 MHz decreases with frequency. The dielectric behavior shows strong frequency as well as composition dependence.     

Biodegradation of Direct Red 5B, a textile dye by newly isolated Comamonas sp. UVS

Soil samples collected from the vicinity of "Manpasand textile industry", located near Ichalkaranji, India were studied for screening and isolation of bacterial strains capable of degradation of textile dyes. A potential strain was selected on the basis of rapid dye degradation and later identified as Comamonas sp. UVS. Comamonas sp. UVS showed 100% decolorization of Direct Red 5B (DR5B) dye at 40 degrees C and pH 6.5. The maximum Direct Red 5B concentration decolorized was 1100mg/l in nutrient broth within 125h. A numerical simulation with the Michaelis-Menten kinetics model gives an optimal value of 16.01+/-0.36mgdye/gcell/h for maximum rate (V(max)) and 7.97+/-0.21mg/l for the Michaelis constant (K(m)). The induction in the activities of laccase and LiP was observed during decolorization. These enzymes were inhibited by the addition of sodium azide. The biodegradation was monitored by UV-vis, FTIR spectroscopy and HPLC. The GCMS analysis indicated the presence of 7-benzoylamino-3-diazenyl-4-hydroxy-naphthalene-2-sulfonic acid in degraded product of the dye. The germination of Triticum aestivum seeds was inhibited with DR5B treatment but not with the treatment of dye degradation products.     

Potentiometric and Thermodynamic Studies of (N-[-(4-Chlorophenyl) Methylene]Nicotinohydrazide) and Its Transition Metal Complexes

Abstract

Pharmacologically active organic ligands (N-[-(4-chlorophenyl) methylene] nicotinohydrazide) synthesized through the condensation of equimolar mixture of anti-mycobacterial agent (nicotinohydrazide) with aromatic aldehyde. The reaction progress and purity of organic ligands were verified by thin layer chromatography. Formation of organic ligands was confirmed with the help of MP, IR, ¹H NMR, 13C NMR and elemental analysis. Further formation of complexes of transition elements such as Mn(II), CO(II), Ni(II), Cu(II) and Zn(II) with organic ligand (Schiff base) N-[-(4-chlorophenyl)methylene] nicotinohydrazide were studied by the pH-metric technique at 25?°C, 35?°C and 45?°C in 70% (v/v)ethanol – water medium at 1?M (NaClO₄) ionic strength. The stability constants of these binary complexes were evaluated and order of stability constant found as Co (II) < Mn (II) < Ni (II) < Cu (II) < Zn (II). The thermodynamic parameters associated with the complexation reactions also were calculated. It is found that the change in enthalpy (ΔH) and change in Gibb’s free energy (ΔG) were negative for all of the systems which suggested that all of the reactions were exothermic. The change in entropy (ΔS) found positive for most of the complexes which indicate in metal-ligand binding process is entropy favorable.     

Effect of Fe – substitution on phase transformation,optical, electrical and dielectrical properties of BaTiO<Subscript>3</Subscript> nanoceramics synthesized by sol-gel auto combustion method

The structural, microstructural, optical, electrical and dielectrical properties of nanocrystalline Fe substituted BaTiO₃ synthesized by sol-gel auto combustion have been investigated. The X-ray diffraction (XRD) analysis revealed the existence of the tetragonal phase for lower Fe content (x = 0.0–0.3) whereas, coexistence of the tetragonal and hexagonal structure of higher Fe content (x = 0.4 and 0.5). The lattice constant (a and c) and unit cell volume (V) increases with increase in Fe content; and an average crystallite size (t) was recorded in the range of ~14–20 nm. The surface morphology as examined using field emission scanning electron microscopy (FESEM) and the compositional stoichiometry was confirmed by energy dispersive spectrum (EDS) analysis. The UV-Vis spectra showed that the band gap energy sensitively depends on the Fe concentration x. DC-electrical conductivity (σ) was recorded in the temperature range of 333–714 K which was found to be increases with increasing temperature and Fe concentration; indicating that an electrical conduction was a thermally activated process. The type of temperature dependent DC conductivity indicates that the electrical conduction in the material is a thermally activated process. The dependencies of the conductivity contributions were predicted from the simple defect model presented, in which oxygen vacancies charge compensate Fe substitution of Ti. Dielectrical property was measured as a function of frequency in the range 50 Hz - 5 MHz at room temperature which was found to be higher at lower frequencies. Dielectric constant (ε’) and loss tangent (tan δ) shows strong compositional as well as frequency dependences.     

Study of bactericidal efficiency of magnetron sputtered TiO2 films deposited at varying oxygen partial pressure

TiO₂ thin films have been deposited at different Ar:O₂ gas ratios (20:80,70:30,50:50,and 40:60 in sccm) by rf reactive magnetron sputtering at a constant power of 200 W. The formation of TiO₂ was confirmed by X-ray photoelectron spectroscopy (XPS). The oxygen percentage in the films was found to increase with an increase in oxygen partial pressure during deposition. The oxygen content in the film was estimated from XPS measurement. Band gap of the films was calculated from the UV-Visible transmittance spectra. Increase in oxygen content in the films showed substantial increase in optical band gap from 2.8 eV to 3.78 eV. The Ar:O₂ gas ratio was found to affect the particle size of the films determined by a transmission electron microscope (TEM). The particle size was found to be varying between 10 and 25 nm. The bactericidal efficiency of the deposited films was investigated using Escherichia coli (E. coli) cells under 1 h UV irradiation. The growth of E. coli cells was estimated through the Optical Density measurement by UV-Visible absorbance spectra. The qualitative analysis of the bactericidal efficiency of the deposited films after UV irradiation was observed through SEM. A correlation between the optical band gap, particle size and bactericidal efficiency of the TiO₂ films at different argon:oxygen gas ratio has been studied.     

Development of stable emulsified formulations of Terminalia arjuna for topical application: evaluation of antioxidant activity of final product and molecular docking study

Abstract

Objective: The aim of this work was to develop stable emulsified formulations containing Terminalia arjuna (T. arjuna) extract and to assess antioxidant potential of the final product with in silico molecular screening.

Methods: Terminalia arjuna emulsified formulations were prepared by application of ternary phase diagram design and were evaluated for phytochemical screening, solubility studies, ex vivo permeation study, DPPH free radical scavenging assay, anti-tyrosinase activity, skin irritation, stability studies, molecular docking study, and pharmacophore modeling.

Results: Phytochemical screening resulted in the presence of secondary metabolites. The result of the solubility study exhibited that olive oil, tween 80, and PEG 400 could be the most appropriate combination for preparation of the emulsified system. The ex vivo study showed adequate release from its emulsified formulation. Globule size determination and Zeta potential analysis indicate the stability of the emulsified system. The result of DPPH free radical scavenging activity and anti-tyrosinase activity of the final product were satisfactory. Skin irritation test on albino rats resulted in no allergic dermal effects. All the prepared formulations were found to be stable upon storage for 3?months. Molecular docking resulted in antioxidant potential via tyrosinase inhibitory mechanism mainly by hydrogen bonding interaction with His60B, Glu158B, His208B, Asn205B, Met215B, His42B, and Asn57B whereas ionic interactions by Arg209B and Val218B of tyrosinase. Pharmacophore modeling describes the similarity features with the standard.

Conclusions: The results suggest that developed emulsified formulations with T. arjuna extract for topical application demonstrate interesting attributes to be explored as potential pharmaceutical products.