Marine pollution assessment near Alexandria,Egypt by Thematic Principal Components (TPC)

This work deals with the detection, identification and mapping of different types of pollutants in the marine environment through the application of a refined image processing technique. The technique is based on the use of already available information on each theme. Classification routines, based on selection of training areas and application of thematic principal components (TPC) analysis, are carried out. The procedure, results, and accuracy testing are presented and discussed. Application to the problem of identification of pollution in Lake Maryout, Egypt, is presented using SPOT images. Results indicate better separability and higher accuracy than traditional techniques.     

A security enhanced robust audio steganography algorithm for image hiding using sample comparison in discrete wavelet transform domain and RSA encryption

Multimedia Tools and Applications - Steganography is the technique of hiding any secret information like text, image or video behind a cover file. Audio steganography is one of the widespread data...     

Effect of poly(ε-caprolactone) and titanium (IV) dioxide content on the UV and hydrolytic degradation of poly(lactic acid)/poly(ε-caprolactone) blends

The effect of accelerated weathering degradation on the properties of poly(lactic acid) (PLA)/poly(ε-caprolactone) (PCL) blends and PLA/PCL/titanium (IV) dioxide (TiO₂) nanocomposites are presented in this paper. The results show that both polymers are susceptible to weathering degradation, but their degradation rates are different and are also influenced by the presence of TiO₂ in the samples. Visual, microscopic and atomic force microsocpy observations of the surface after accelerated weathering tests confirmed that degradation occurred faster in the PLA/PCL blends than in the PLA/PCL/TiO₂ nanocomposites. The X-ray diffraction results showed the degradation of PCL in the disappearance of its characteristic peaks over weathering time, and also confirmed that PLA lost its amorphous character and developed crystals from the shorter chains formed as a result of degradative chain scission. It was further observed that the presence of TiO₂ retarded the degradation of both PLA and PCL. These results were supported by the differential scanning calorimetry results. The thermogravimetric analysis results confirmed that that PLA and PCL respectively influenced each other's thermal degradation, and that TiO₂ played a role in the thermal degradation of both PLA and PCL. The tensile properties of both PLA/PCL and PLA/PCL/TiO₂ were significantly reduced through weathering exposure and the incorporation of TiO₂.     

Analysis of uniform circular arrays for adaptive beamforming applications using particle swarm optimization algorithm

In this article, the particle swarm optimization algorithm is used to calculate the complex excitations, amplitudes and phases, of the adaptive circular array elements. To illustrate the performance of this method for steering a signal in the desired direction and imposing nulls in the direction of interfering signals by controlling the complex excitation of each array element, two types of arrays are considered. A uniform circular array (UCA) and a planar uniform circular array (PUCA) with 16 elements of half‐wave dipoles are examined. Also, the performance of an adaptive array using 3‐bit amplitude and 4‐bit phase shifters are studied. In our analysis, the method of moments is used to estimate the response of the dipole UCAs in a mutual coupling environment. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008.     

Rehabilitation of Masonry Walls Using Unobtrusive FRP Techniques for Enhanced Out-of-Plane Seismic Resistance

Earthquake damage to unreinforced masonry buildings has shown the vulnerability of perimeter walls to out-of-plane failure. This paper describes a study that was carried out to develop and test innovative fiber reinforced polymer (FRP) rehabilitation techniques that meet the stringent requirements for strengthening historical buildings and to be cost-effective alternatives applicable to other existing masonry structures. Unobtrusive FRP rehabilitation techniques that utilize flexible carbon fiber composite cables, mounted near the surface of the fa?ade walls in epoxy-filled grooves in the bed and head joints, were developed. Ten full size walls were constructed of clay bricks and retrofitted using the developed FRP rehabilitation techniques. The test results demonstrated the high efficiency of the rehabilitation techniques under both monotonic and quasistatic cyclic loadings. Significant increases in ultimate capacities, energy absorption, and deformability were achieved for various reinforcing schemes compared to the behavior of the unreinforced walls.     

An optimal wavelet-based multi-modality medical image fusion approach based on modified central force optimization and histogram matching

Multimedia Tools and Applications - This paper introduces an optimal solution for wavelet-based medical image fusion using different wavelet families and Principal Component Ana1ysis (PCA) based on...     

[3+2]-Cycloadditions of nitrilimines with heteroaryl thioketones

The in situ generated nitrilimines are trapped efficiently with heteroaryl thioketones bearing thiophen-2-yl or selenophen-2-yl substituents. The exclusive products observed in these reactions are 2,3-dihydro-1,3,4-thiadiazoles formed via regioselective [3+2]-cycloaddition. Competitive head-to-tail dimerization of the intermediate 1,3-dipoles was not observed in any of the studied reactions.     

Load-Displacement of Masonry Panels with Unbonded and Intermittently Bonded FRP. I: Analytical Model

An experimental study was carried out to develop and test innovative fiber-reinforced polymer (FRP) rehabilitation techniques that meet the stringent requirements of restoration of historical buildings and are cost-effective alternatives applicable to existing masonry structures. In these techniques, FRP reinforcement was either unbonded or intermittently bonded to the masonry wall. In order to analyze performance, extend the range of the investigated parameters, and define limitations, a simplified analytical model was developed to predict the postcracking lateral load-displacement response under biaxial bending. The response of the retrofitted walls cannot be modeled by conventional approaches. The proposed model is based on balancing internal and external work and rigid body mechanics. It is assumed that all postcracking deformations take place at cracks between wall subpanels. Postcracking displacements are calculated from rotation rather than curvature. The adequacy of the model was verified by comparisons with the experimental results and a good agreement was found. The model could be used as the basis for a design method.