Cathodic electrodeposition of CdMn2O4 nanoplates and evaluation of the charge storage ability

Journal of Solid State Electrochemistry - The present work describes a facile route for the synthesis of CdMn2O4 nanoplates. The nanoplates were synthesized by cathodic electrogeneration of base...     

Cyclization of N-benzyl cyanoacetamide: Novel synthesis and biological activity of pyrrole,pyrimidine, and pyran derivatives

Heteroannulation of N-Benzyl cyanoacetamide 1 to a new series of heterocycles has been developed. Thus, reaction of 1 with different polarized π systems afforded pyrrolo 4 , pyridone 6 , pyridine 8 , and diazapene 10 derivatives, respectively. N-Benzyl cyanoacetamide that undergo condensation reaction with salicylaldehyde yielded pyran derivative 11 . Nitrosation of 11 furnished condensed pyran 13 . Compound 11 reacted with benzaldehyde, carbon disulfide (cyclizing agent), and ammonium thiocyanate to provide pyrane 17 , thiazine 18 , and thiourea 20 derivatives, respectively. Cinnamoyl isothiocyanate was reacted with compound 11 to produce non-isolable thiourea derivative 21 . The newly synthesized compounds have been characterized by infrared (IR), proton nuclear magnetic resonance (¹H NMR), and carbon nuclear magnetic resonance (¹³C NMR) spectral data. The compounds were then evaluated for antibacterial and anticancer activities.     

Characterization of bis-Schiff bases synthesized using ZnFe2O4 nanoparticles as catalyst,and examination of their antibacterial and in vitro cytotoxic properties

In this study, ZnFe₂O₄ nanoparticles (NPs) were prepared by a hydro/solvothermal method, and their structures were characterized by infrared, scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analyses. These ZnFe₂O₄ NPs were used in the synthesis of new bis-Schiff bases by condensation of hydroxyl-substituted aldehydes with various aromatic diamines in aqueous media. The antimicrobial activities of the synthesized bis-Schiff bases were tested against gram-negative as well as gram-positive bacteria. The MTT method was used to assess the anticancer activity of the bis-Schiff bases towards human lung and breast cancer cell lines. The results indicated that these compounds could be considered as new anti-tumor candidates.     

The influence of acceleration and deceleration on shock wave movement on and around aerofoils in transonic flight

This paper examines the shock wave dynamics of a biconvex aerofoil in transonic flight during acceleration and retardation. The aerofoil has a cord length of 1 m and air at infinity is at 101.325 kPa and 300 K. Using Fluent as the CFD software, constant velocity (steady state) simulations were conducted at transonic Mach numbers. The aerofoil was then accelerated at 1041m/s² (106 g), starting at Mach 0.1, and decelerated at −1041m/s², starting at Mach 1.6, through the same range of Mach numbers using time-dependent (unsteady) simulations. Significant differences were found in the transonic region between the steady and the unsteady aerodynamic forces. Analysis of the flow field in this region showed that acceleration-dependent variations in the position of the shock wave on the surfaces of the aerofoil were the main reason for this. As very high accelerations were used in order to emphasize differences, which do not have many practical applications, simulations using accelerations lower than 9 g were also conducted in order to confirm the results. The acceleration-dependent behaviour of other shock waves around the aerofoil, such as the bow shock in front of the aerofoil and the trailing wave were also examined. The trailing wave followed behind the aerofoil changing position with different accelerations at the same Mach number.      

Nonlinear dynamics of doubly curved shallow microshells

The nonlinear dynamical characteristics of a doubly curved shallow microshell are investigated thoroughly. A consistent nonlinear model for the microshell is developed on the basis of the modified couple stress theory (MCST) in an orthogonal curvilinear coordinate system. In particular, based on Donnell’s nonlinear theory, the expressions for the strain and the symmetric rotation gradient tensors are obtained in the framework of MCST, which are then used to derive the potential energy of the microshell. The analytical geometrically nonlinear equations of motion of the doubly microshell are obtained for in-plane displacements as well as the out-of-plane one. These equations of partial differential type are reduced to a large set of ordinary differential equations making use of a two-dimensional Galerkin scheme. Extensive numerical simulations are conducted to obtain the nonlinear resonant response of the system for various principal radii of curvature and to examine the effect of modal interactions and the length-scale parameter.     

Softening Hard Water Using High Frequency Spark Plasma Discharge

Effects of high frequency spark plasma discharge as a time efficiency method in order to softening the natural hard water has been investigated experimentally. A very hard water sample with 331 ± 19 mg/l of CaCO₃ hardness was used. The current and voltage of each spike was about 9.6 A and 3.5 kV respectively at 16 kHz frequency with 35 μs pulse width. Hard water was treated for 2, 4, 6, and 8 min. The concentration of CaCO₃, Ca²⁺ ions, Mg²⁺ ions and pH as well as water conductivity was controlled before and after treatment. The concentration of CaCO₃ dropped by 70%, after 8 min treatment. During the treatment, the pH had a fluctuation about 1.5 and finally remained in neutral state. Also the elemental composition, crystalline structure and morphology of the precipitates were identified. Molecular dynamics simulation revealed that the ozone and hydroxyl play important roles in the softening of the hard water.     

Graph norms and Sidorenko’s conjecture

Let H and G be two finite graphs. Define h _H (G) to be the number of homomorphisms from H to G. The function h _H (·) extends in a natural way to a function from the set of symmetric matrices to ℝ such that for A _G , the adjacency matrix of a graph G, we have h _H (A _G ) = h _H (G). Let m be the number of edges of H. It is easy to see that when H is the cycle of length 2n, then h _H (·)^1/m is the 2n-th Schatten-von Neumann norm. We investigate a question of Lovász that asks for a characterization of graphs H for which the function h _H (·)^1/m is a norm.     

Cyclodextrin-enclosed substances of Brazilian propolis

By using beta-cyclodextrin-inclusion as a unique technique, an efficient separation of pharmacologically active phenolic compounds from Brazilian propolis was achieved to provide one new compound, 3-(3-hydroxy-3-methyl-butyl)-5-prenyl-4-hydroxycinnamic acid, together with two common cinnamic acid derivatives, artepillin C and capillartemisin A, and two known flavanols, aromadendrin and 3,5,7-trihydroxy-4'-methoxyflavanol.     

A molecular orbital treatment of the electronic spectra of some tryptamines

The electronic absorption spectra of tryptamine, 5-methoxytryptamine, 6-fluorotryptamine, N-acetyl-5-hydroxytryptamine, gramine, and melatonin were investigated. The observed transitions were π–π*, and the values of band maxima and intensity reflected an extent of interaction between the indole ring and the alkylamine side chain. Molecular orbital calculations at the level of INDO /S –CI were performed on all the studied molecules. State functions and transition energies were calculated. The correspondence between the experimental and theoretical results was satisfactory. © 1992 John Wiley & Sons, Inc.     

Single exposure photography applied to a slow flow field

A speckle photography technique has been applied to measuring the velocity profiles of laminar and turbulent flow through pipes of circular cross-section. A single exposure photography technique has been used to visualize slow fluid flow. The fluids used were seeded with tracer particles whose size range from 20 to about 120 μm in diameter. A mathematical expression representing the recorded intensity is presented. A single exposure with a long exposure time was taken on a holographic film material. The recorded intensity was represented by the convolution product of the image formed and a rectangular function representing a one-dimensional continuous motion. The analysis shows that the intensity distribution of the Fourier spectrum of the diffracted image follows a sinc² function on a noise background representing the scattered light of the tracer particles.