Image Encryption Based on Diffusion and Multiple Chaotic Maps

In the recent world, security is a prime important issue, and encryption is one of the best alternative way to ensure security. More over, there are many image encryption schemes have been proposed, each one of them has its own strength and weakness. This paper presents a new algorithm for the image encryption/decryption scheme. This paper is devoted to provide a secured image encryption technique using multiple chaotic based circular mapping. In this paper, first, a pair of sub keys is given by using chaotic logistic maps. Second, the image is encrypted using logistic map sub key and in its transformation leads to diffusion process. Third, sub keys are generated by four different chaotic maps. Based on the initial conditions, each map may produce various random numbers from various orbits of the maps. Among those random numbers, a particular number and from a particular orbit are selected as a key for the encryption algorithm. Based on the key, a binary sequence is generated to control the encryption algorithm. The input image of 2-D is transformed into a 1- D array by using two different scanning pattern (raster and Zigzag) and then divided into various sub blocks. Then the position permutation and value permutation is applied to each binary matrix based on multiple chaos maps. Finally the receiver uses the same sub keys to decrypt the encrypted images. The salient features of the proposed image encryption method are loss-less, good peak signal-to-noise ratio (PSNR), Symmetric key encryption, less cross correlation, very large number of secret keys, and key-dependent pixel value replacement.Comment: 14 pages,9 figures and 5 tables; http://airccse.org/journal/jnsa11_current.html, 201

Potential of Vibration Studies in the Soil Characterization Around Power Plants – A Case Study

Propagation characteristics of waves generated by the various sources of vibration can be dependent on the type of the generated waves, which can be accessed by measuring particle motion in vertical, longitudinal and transverse direction. The monitoring of motion in three directions on the ground surface and in depth is important for the characterization of propagating waves. Vibrations of the machine foundations induce elastic waves in soil, which may affect surrounding buildings. Generally, the attenuation of vibrations on surface is composed of two factors namely geometric damping and material damping. The paper is an experimental investigation with regard to the ground vibrations and its attenuation during the operation of power plants. The study helps in characterizing the soil around a power plant. The investigation was carried out on two power plants, which runs at the same frequency, and soil characterization was done based on the study. Measurements were taken on the level ground for the harmonic waves generated from the diesel power plant. Study is found to be helpful in characterizing the soil based on the frequency independent material damping coefficients, low amplitude shear modulus etc. on the plant premises. The effect of these vibrations on adjoining areas can be well predicted based on the soil medium

Computational Analysis of Heat Transfer through Fins with Different Types of Notches

The Engine is one of the important component in an automobile which is subjected to high temperature and thermal stresses. In order to cool the engine the fins are another component which are used to dissipate the heat from the Engine. Fins are generally used to increase the heat transfer rate from the system to the surroundings. By doing computational flow analysis on the engine cooling fins, it is helpful to know about the heat dissipation rate and the Principle implemented in this project is to increase the heat transfer rate, so in this analysis, the fins are modified by putting different types of notches and are of same material. The knowledge of efficiency and effectiveness of the fins are necessary for proper designing of fins. The main objective of our analysis is to determine the flow of heat at various notches available and the analysis is done by using ANSYS – CFD Fluent software

Low carbon building: Experimental insight on the use of fly ash and glass fibre for making geopolymer concrete

Due to the environmental impacts resulting from the production of Ordinary Portland cement (OPC), the drive to develop alternative binders that can totally replace OPC is gaining huge consideration in the construction field. In the current study, attempt was made to determine the strength characteristics of glass fibre-reinforced fly ash based geopolymer concrete. Sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) were used as alkaline solutions (for activation of geopolymer reaction) at 12, 16, 20 M. Glass fibres were added to the geopolymer concrete in varying proportions of 0.1e0.5% (in steps of 0.1%) by weight of concrete. A constant weight ratio of alkaline solution to fly ash content of 0.43 was adopted for all mixes. British standard concrete test specimens were cast for measuring compressive strength, splittensile strength, and flexural strength. Concrete specimens were cured by heating in oven at 90 �C for 24 h and natural environment, respectively. From the results, thermally cured concrete samples had better mechanical properties than the ambient (natural) cured samples. Thermally cured concrete specimen, containing 0.3% glass fibre and 16 M NaoH, achieved a maximum compressive strength of 24.8 MPa after 28 d, while naturally cured samples achieved a strength of 22.2 MPa. There was substantial increase in tensile strength of geopolymer concrete due to the addition of glass fibres. Split tensile strength increased by 5e10% in glass fibre-reinforced geopolymer concrete, containing 0.1e0.5% glass fibre and 16 M NaoH when compared to the unreinforced geopolymer concrete (1.15 MPa)

Finite Element Analysis and Experimental Study on the Effect of Extrusion Ratio during Hot Extrusion Process of Aluminium Matrix Composites

The finite element (FE) analysis on the effect of extrusion process parameter namely, extrusion ratio at different billet temperatures on the plastic strain and strain rate of aluminium matrix composite during hot extrusion process has been dealt. The dynamic explicit FE code in ANSYS 15.0 workbench was used for simulation. The FE analysis was carried out on the SiC reinforced aluminium matrix composites for three extrusion ratios 4:1, 8:1 and 15:1, for the billet temperatures in the range 350 °C - 450 °C in steps of 50 °C. The plastic strain and strain rate were found to increase with increase in the extrusion ratio. A minimum strain and strain rate was found to occur at the billet temperature of 450 °C. The silicon carbide particles reinforced aluminium matrix composites were then extruded at the optimised temperature of 450 °C for various extrusion ratios as mentioned above. The effect of extrusion ratio on the microstructure and surface quality of extruded rod was studied

1-Meth­oxy-4-({[(4-meth­oxy­phen­yl)­sulfan­yl](phen­yl)meth­yl}sulfan­yl)benzene

The title compound, C21H20O2S2, forms a propeller-shaped structure with the tetra­hedral C atom as the central hub and meth­oxy­benzene and phenyl residues as radiating blades. Short C—H⋯π contacts are observed