The higher strength 7xxx aluminum alloys exhibited low resistance to stress corrosion cracking (SCC) when aged to the peak hardness (T6 temper). The overaged alloys (T7 temper) developed to enhance the SCC with loss in the strength of the alloy. Recently, retrogression and re-aging (RRA) heat treatments are used for improving the SCC behavior for alloys in T6 tempers such as 7075, 7475 and 8090. In this study, an application of retrogression and re-aging heat treatment processes are carried out to enhance toughness properties of the 7079-T651 aluminum alloy, while maintaining the higher strength of T651-temper. The results of charpy impact energy and electrical conductivity tests show a significantly increases in absorbed energy and electrical conductivity values, when the alloys are exposed to various retrogression temperatures (190, 200, 210°C) and times (20, 40, 60 minutes), and then re-aged at 160°C for 18 hours.

0

We are concerned here with the existence of at least one positive

continuous solution of the quadratic integral equation of fractional orders

x(t) = a(t) + Iαf(t; x(t)) · Iβg(t; x(t)); α; β 2 (0; 1]:

The maximal and minimal solutions are also proved. Some applications are

given.

Digital video steganography has attracted a great deal of research interest in the recent few years in applications. In this paper, we propose a method to embed and encrypt messages into video sequences by using steganography technique Based on the H.264 video coding standard. The system implemented in this work provides robust H.264 video compression constant, without significantly affecting the overall bit rate and quality of the video stream. The results indicate that the algorithm can be implemented steganography fast and efficiently and effect vision and peak signal to noise ratio (PSNR) of video sequences are almost unaffected after decoding.

Steganography is the idea of embedding a secret data in different media and has become an important regulation of methods of data integration. Although the still images are generally applied in the past, is very popular in recent years for the video. The techniques of video data hiding in recent year’s emphasis on the features generated by the video compression standard, a safer method for steganography uses MPEG-4/H.264 Bit Plane Complexity Segmentation (BPCS) algorithm is proposed in this approach. The reason for choosing such a video coverage is the enormous amount of data that can be hidden in each frame of MPEG-4 video. In other words, MPEG-4 has three types of images: I-frame, B, and P frames. Unlike other techniques used to hide data, such as the LSB algorithm, PBCS can achieve better results in both mathematics expression and human vision. In this paper, data is embedded in the videos of the I-frame until the BPCS can reach high levels of integration with low distortion based on the theory that regions of low noise-levels as in a picture can be replaced by noise without a significant loss of image quality. This approach invents data hidden in high-security environments. Experimental results show the success of hidden data in the selected and extracted data from the sequence of frames and also indicate the effectiveness of the implementation plan of steganography compressed video with high security features.

Few studies have systematically addressed evolutionary changes in olfactory neuron assemblies, either by genetic drift or as an

adaptation to specific odor environments. We have studied the sense of olfaction in 2 congeneric scarab beetles, Pachnoda

interrupta Olivier and Pachnoda marginata Drury (Coleoptera: Scarabaeidae: Cetoniinae), which are both opportunistic

polyphages, feeding mainly on fruit and flowers. The 2 species occur in dissimilar habitats: P. interrupta is found in dry

savannah, and P. marginata in tropical parts of equatorial Africa. To study how these species may have adapted their sense of

olfaction to their odor environments, we utilized single-unit electrophysiology on olfactory sensilla with a wide selection of

food-related compounds. Despite the differences in habitat, we found that the species shared most of the physiological types

of olfactory receptor neurons (ORNs) encountered, although their proportions frequently varied between the species. The high

degree of conservation in olfaction between the species implies that a similar sensory strategy is efficient for food search in

both habitats. However, shifts in proportions of receptor neuron classes, and slight shifts in response profiles and/or presence

of some ORN classes unique to either species, may reflect adaptation to a different set of hosts.

Key words: comparative study, electrophysiology, olfaction, polyphagous herbivore, single sensillum recordings

0

The present paper discusses the hydro-environmental degradation of New Damietta City due to salinity and waterlogging. Forty-one water samples were collected and analyzed for various hydrochemical parameters. The majority of samples are enriched in chloride, sulfate, sodium, and magnesium (also, a chloride-sodium category dominates the majority of the analyzed samples). These data reflect that the marine origin plays a major role in controlling the groundwater composition. The shallow saline groundwater with high concentrations of both chloride and sulfate salts significantly affects the characters and accelerates the rate of concrete deterioration, particularly the reinforced concrete and underground utilities.