New exact solutions of the Tzitzéica-type equations in non-linear optics using the expa function method

One specific class of non-linear evolution equations, known as the Tzitzéica-type equations, has received great attention from a group of researchers involved in non-linear science. In this article, new exact solutions of the Tzitzéica-type equations arising in non-linear optics, including the Tzitzéica, Dodd–Bullough–Mikhailov and Tzitzéica–Dodd–Bullough equations, are obtained using the exp_a function method. The integration technique actually suggests a useful and reliable method to extract new exact solutions of a wide range of non-linear evolution equations.     

Quasi-static compressive behaviour of aluminium cenosphere syntactic foams

In this paper, cenosphere particles embedded in AA2014 aluminium matrix are used to fabricate syntactic foam by stir casting method. The particle size is about 100?µm and foam density is about 1990?kg?m^?3. Compression tests at strain rate 0.001/s are performed on foam samples to characterise their mechanical properties which are then used in numerical analysis on commercial finite element analysis software ABAQUS/CAE with isotropic elastic-plastic material model. Experimental and numerical results show good conformity in deformation behaviour with elastic and plateau zones showing average deviations less than 5% and 20%, respectively. Foams showed high yield stress and energy absorption capabilities that can be useful in making blast and impact resistant structures.     

Finding all hops shortest paths

In this letter, we introduce and investigate a new problem referred to as the All Hops Shortest Paths (AHSP) problem. The AHSP problem involves selecting, for all hop counts, the shortest paths from a given source to any other node in a network. We derive a tight lower bound on the worst-case computational complexities of the optimal comparison-based solutions to AHSP.     

Influence of the silicon surface treatment by plasma etching and scratching on the nucleation of diamond grown in HFCVD - a comparative study

A comparative study for the nucleation of diamond was carried out using surface treatment like (i) surface scratching with 1 μm diamond paste and (ii) surface etching using chlorine plasma at different RF powers (50, 100 and 150 W). Atomic force microscopic study shows variation in roughness from 31 nm to 110 nm. Scratching results in random scratches, whereas plasma etches a surface uniformly. Scanning electron microscopic observations show well faceted crystallites with a predominance of angular shaped grains corresponding to 〈100〉 and 〈110〉 crystallite surfaces for the scratched as well as plasma etched substrate. Surface etching at 150 W plasma power results in a better growth in comparison with 50 and 100 W plasma powers. Chlorine-radical is found responsible for the changes in the growth morphology. Raman spectroscopy shows a sharp peak at 1,332 cm⁻¹ and a peak at ∼1,580 cm⁻¹ for both samples.     

The influence of chloride-ion concentration on the Pitting of steel in simulated concrete environment

The influence of chloride-ion concentration on the pitting behaviour of steel in saturated Ca(OH)₂ solution was studied using the D.C. polarization technique. Results seem to indicate a threshold chloride level for the on-set of severe pitting around 3000 ppm, the pitting potential E_p exhibits dramatic drop and large hysteresis loops develop. The results provide insight into the pitting performance of steel in concrete and highlight the poor repassivation of this metal/environment system.     

Rate sensitivity of high birefringent fiber optic sensors underlarge dynamic loads

New experimental studies on the effects of large dynamic compressive loads on highly birefringent optical fibers are presented. The intensity rate of applied dynamic loads ranged between 2.18-6719 KN/m-sec. A Fibercore (previously York) HB600 Bow-Tie fiber with an initial beat length of 1.16 mm was employed in the present study. Sensor response is discussed in terms of the effects of force amplitudes and velocities on the calibration parameter T_f. T_f is a function of the amplitude as well as the velocity of applied loading. Therefore, calibration of the sensor should be achieved through regression analysis of the load-fringe data for the entire spectrum of the desired force velocities. The ramification of this finding is that a single experiment for the measurement of T_f cannot provide the required parameters for calibration. This further implies that the change in beat length is also dependent on the amplitude and velocity of loading. The suggested method takes both effects into account through empirical analysis of experimental data     

Large deformation analysis in the context of 3D compressible nonlinear elasticity using the VDQ method

In this article, a new solution approach is developed to numerically compute large deformations of 3D hyperelastic solids based on the compressible nonlinear elasticity. The governing equations are derived by the minimum total potential energy principle, and the Neo-Hookean model is used for the hyperelastic character of material. One of the key novelties of the work is its formulation in which the tensor form of equations is replaced by an efficient matrix–vector form that can be readily utilized in the coding process. Moreover, the variational differential quadrature technique is adopted to arrive at the discretized governing equations in a direct way. Simple implementation, fast convergence rate, and computational efficiency are the main advantages of present approach. Through some examples, the accuracy and effectiveness of the proposed numerical approach are revealed.

     

An Insight View on Synthetic Protocol,Surface Activity,and Biological Aspects of Novel Biocompatible Quaternary Ammonium Cationic Gemini Surfactants

In this study, we prepared a novel series of diester-functionalized cationic gemini surfactants (C_m-E2O2-C_m) containing ethylene oxide as a spacer with varying alkyl chain lengths and characterized by ¹H NMR, FT-IR, elemental analysis, and ESI-MS. The physicochemical properties of the geminis were explored by tensiometry, fluorescence, dye solubilization, and Krafft point. These geminis acquire superior surface activity than the conventional surfactants. Fluorescence spectroscopy analysis affirmed that the micropolarity and aggregation number of micelles diminished with increase in the alkyl chain length. These geminis represent a new group of amphiphiles of considerably high biodegradability, better cleavability, and low toxicity as assessed by BOD test, FT-IR analysis, and HC₅₀ analysis, respectively. They also showed significant level of antimicrobial activity toward some specified bacterial strains of Gram-positive and Gram-negative by using agar well diffusion method. Furthermore, the thermogravimetric analysis provided information regarding thermal stabilities of the newly synthesized gemini surfactants.