Energy, momentum and angular momentum in the dyadosphere of a charged spacetime in teleparallel equivalent of general relativity

We apply the energy momentum and angular momentum tensor to a tetrad field, with two unknown functions of radial coordinate, in the framework of a teleparallel equivalent of general relativity (TEGR). The definition of the gravitational energy is used to investigate the energy within the external event horizon of the dyadosphere region for the Reissner-Nordström black hole. We also calculate the spatial momentum and angular momentum.     

Some characterizations of a new metal–organic framework (n-C14H29NH3)2CdCl4 and the role of hydrogen bonding

A cadmium-based organic–inorganic hybrid (n-C₁₄H₂₉NH₃)₂CdCl₄ is synthesized and characterized, thermally and dielectrically. The differential scanning calorimetery (DSC) and the differential thermal analysis (DTA) thermograms were performed in a suitable range of temperature. The general feature of each thermogram indicates that the hybrid undergoes two structural phase transitions at T_major ≈ 351.5?K and T_minor ≈ 344.66?K in addition to an intermediate temperature which is located at ≈346.8?K. For further confirmation of the observed phase transitions, the complex dielectric permittivity ε* (ω,T)?=?ε′(ω,T) – iε″(ω,T) and ac conductivity σ_ac(ω,T) were accurately measured in the wide range of temperature 100?K<T<400?K at some suitable range of frequencies. The data evidenced the existence of such transitions. Comparison with other hybrids reveals the absence of the odd–even effect whereas the transition temperature increases with the increase of the chain length. The mechanism of proton transfer and kink defects was outlined.     

A new approach for colored watermarking image into gray scale image using wavelet fusion

With the quick growth of technologies and great spread of the Internet, many challenges face data hiding. Nevertheless, significant data may be protected by burring it in an image as a watermark. This paper shows an efficient data hiding watermarking approach for color image by using singular value decomposition (SVD), multi-level discrete wavelet transform (DWT) and wavelet fusion. The main idea in this work is to separate the color image into its basic components (three channels); red, green, and blue. Then, fuse every channel with an image which is gray scale and integrate the three fused images into one gray scale fused image. Finally, the fused image is burred into a cover gray scale image to produce the watermarked image by using DWT and SVD. The proposed approach evaluation is done by using several images and different hacking on the transmitted image. The experimental results show that the marked images which are generated by the proposed approach are tolerant to versatile attacks such as Gaussian, blur, wrap, and cropping. Above all, the extracted watermark images are recognized even when the watermarked images suffered from attacks.     

MΦller＇s Energy of Kerr-NUT Metric

The energy distribution of the Kerr-NUT （Newman-Unti-Tamburino） spacetime is calculated using MΦller＇s energy-momentum complex within the framework of the Riemannian geometry.     

Complete synchronization of chaotic complex nonlinear systems with uncertain parameters

Our main objective in this work is to investigate complete synchronization (CS) of n-dimensional chaotic complex systems with uncertain parameters. An adaptive control scheme is designed to study the synchronization of chaotic attractors of these systems. We applied this scheme, as an example, to study complete synchronization of chaotic attractors of two identical complex Lorenz systems. The adaptive control functions and the parameters estimation laws are calculated analytically based on the complex Lyapunov function. We show that the error dynamical systems are globally stable. Numerical simulations are computed to check the analytical expressions of adaptive controllers.     

Synthesis of sulfur-containing heterocycles via ring enlargement

The current review deals with the use of ring expansion reactions for the synthesis of sulfur-containing heterocycles. Ring enlargement offers by far a convenient method for the synthesis of ‘medium-sized ring systems’, which are usually difficult to obtain or even produced in low yields. These reactions are often catalytically processed starting from a single cyclic precursor and, therefore, are superior to alternative classical iterative synthetic approaches in terms of atomic and conversion efficiency. The current review aims to shed light on the synthetic approaches that exist to afford medium-sized sulfur heterocycles from preexisting smaller rings (e.g., three-, four-, five-, six- and seven-membered rings).     

A novel method for the synthesis of 1-aryltetrahydroisoquinolines

Carbenium ions generated from substituted benzhydryls using acid catalysis undergo smooth intramolecular trapping by pendant sulfonamide groups to provide excellent yields of 1-aryltetrahydroisoquinolines.     

N-sulfonylbenzotriazoles as advantageous reagents for C-sulfonylation

[Structure: see text]. Reactions of readily available N-(alkyl-, aryl-, and heteroarylsulfonyl)benzotriazoles 3a-h with diverse nitriles, reactive heteroaromatics, alkylheteroaromatics, sulfones, and esters produced alpha-cyanoalkyl sulfones 5a-i, sulfonylheteroaromatics 7a-e, alpha-(sulfonylalkyl)heterocycles 9a-f, alpha-sulfonylalkyl sulfones 11a-g, and esters of alpha-sulfonyl acids 14a-c, respectively, in synthetically useful to excellent yields. The results represent the first examples of the successful application of sulfonylazoles for C-sulfonylation.     

An extensive study of bromination of cis,trans,trans-1,5,9-cyclododecatriene: product structures and conformations

Bromine has been added to cis,trans,trans-1,5,9-cyclododecatriene under various reaction conditions. All expected direct addition products have been isolated, and their structures have been determined by microanalysis, NMR and X-ray crystallography. Advanced NMR techniques were used to determine solution conformations of several of the compounds, enabling comparison with the solid-state conformations obtained by crystallography.     

Study of regioselective methanesulfonylation of simple aromatics with methanesulfonic anhydride in the presence of zeolite catalysts

Regioselective methanesulfonylation of simple aromatics using methanesulfonic anhydride can be achieved over zeolite catalysts. For example, methanesulfonylation of toluene over various cation-exchanged zeolite beta catalysts affords higher para-selectivity in the synthesis of methyl tolyl sulfone than standard Friedel-Crafts methanesulfonylation utilising aluminium chloride.