In this paper autonomous and nonautonomous modified hyperchaotic complex L¨ usystemsare proposed. Our systems have been generated by using state feedback and complex periodic forcing. The basic properties of these systems are studied. Parameters range for hyperchaotic attractors to exist are calculated. These systems have very rich dynamics in a wide range of parameters. The analytical results are tested numerically and excellent agreement is found. A circuit diagram is designed for one of these hyperchaotic complex systems and simulated using Matlab/Simulink to verify the hyperchaotic behavior.

In this paper autonomous and nonautonomous modified hyperchaotic complex L¨ usystemsare proposed. Our systems have been generated by using state feedback and complex periodic forcing. The basic properties of these systems are studied. Parameters range for hyperchaotic attractors to exist are calculated. These systems have very rich dynamics in a wide range of parameters. The analytical results are tested numerically and excellent agreement is found. A circuit diagram is designed for one of these hyperchaotic complex systems and simulated using Matlab/Simulink to verify the hyperchaotic behavior.

We study rheotaxis of bull sperm inside microchannels to characterize the effects of flow and wall shape on sperm swimming behavior. We found that large percentage, 80 to 84%, of sperm cells exhibited positive rheotaxis (sperm cells swimming against the flow) within flow velocities of 33 to 134 µm/s. Sperm cells were also found to reverse their swimming direction when liquid flow direction was reversed. Time taken by sperm cells to reverse their swimming direction was inversely proportional to flow velocity. Sperm behavior was significantly affected by sperm position with respect to channel wall. Sperm cells close to channel wall moved upstream faster than sperm cells moving along channel centerline. Shear stress, which is an indicator of velocity distribution, was found to play an important role in regulating rheotactic behavior of sperm cells. Side pockets were added to some microchannels to mimic storage sites in mucosal folds and pockets in the fallopian tube of female reproductive system and sperm interaction with these pockets was monitored. We found that sperm cells tend to follow channel walls and enter these pockets without any chemical binding, which further confirms the wall tracking behavior of mammalian sperm cells. Our results confirm that sperm rheotaxis is a strong mechanism for guiding sperm cells to the oocyte along the female genital tracts.

Content-based image retrieval systems have become a reliable tool for many image database applications. There are several advantages of the image retrieval techniques compared to other simple retrieval approaches such as text-based retrieval techniques. This paper proposes an image retrieval technique that can be used for retrieving color images. In this paper, we propose two variations of an image abstraction technique based on signature bit strings and an appropriate similarity metric. The technique provides a compact representation of an image based on its color content and yields better retrieval effectiveness than classical techniques based on the images' global color histograms (GCHs). The proposed technique has many applications. These applications are described in details in this paper.

In this paper, we propose a novel approach for 3D surface reconstruction of the hu- man jaw. Due to the difficulties of setting up a data acquisition system inside the mouth, we use an intra-oral camera to capture a sequence of calibrated images. These images are registered together to build a panoramic view of the jaw. We incorporate a shape from shading(SFS) algorithm that benefits from camera calibration parameters to build a 3D model from the panoramic image obtained from the previous stage. Our approach results in a 3D surface which has more fine details compared with those resulting from other lit- erature techniques. We will demonstrate different artificial jaws surfaces reconstruction to show the efficiency of our system

The macro-models method is one of the main categories for modeling infills based on the equivalent strut method. The basic parameter of these struts is their equivalent width, which affects the stiffness and strength. This paper presents a general review of several expressions proposed by researchers to calculate this equivalent width. The comparative study of different expressions shows that the Paulay and Priestley equation is the most suitable choice for calculating the diagonal equivalent strut width, due to its simplicity and because it gives an approximate average value among those studied in this paper. Consequently, the model will be used in our further study for analysis of RC infilled frames.

Pillars are designed to ensure regional stability or local support in stopes and along drifts, or to yield under a measure of control. In all cases, the strength of the material and the variations in strength must be known both for the pillar and for the roof and floor. The stability in longwall faces depends mainly on the interaction between the roof strata, face support, roadway support and dimensions of pillars. The main aim of this paper is to apply rock mass classification systems to longwall pillar design at Abu-Tartur mining area. The pillar load is estimated taking into account the physical and mechanical properties of phosphate deposit and roof rock, panel width, mining height, depth below surface. Two methods from classification systems are used in calculation pillars stress and strength to pillars design namely Geological Strength Index (GSI) and Rock Mass Rating (RMR) systems. GSI values for immediate, main roof rocks and phosphate ores are determined from geological conditions, as lithology, structure of the interlocking of rock blocks and the conditions of the surfaces between these blocks. RMR value can be determined by correlation it with GSI system. The pillar widths calculated by applying rock mass classifications (GSI& RMR) are 49m and 64m at a factor of safety 2 and panel width 100m with extraction ratios of 70 and 64 % respectively. The data used in calculations are collected from geological reports of the company and from laboratory tests of phosphate ores and shale rocks in the roof.

β Diversity is an ecological concept used to describe the turnover of species across a wide range of spatial and temporal scales, but such knowledge is lacking for macroalgal assemblages of the Red Sea. β Diversity patterns for Red Sea macroalgae were evaluated from different sites (Hurghada, Safaga, and Al-Quseir) and seasons across different environmental disturbances. β Diversity was studied by partitioning the total number of species (γ diversity) into additive components. Geographical heterogeneity was more important than seasonal heterogeneity in structuring macroalgae both at species and functional group levels. Species replacement as a component of β diversity produced dissimilarity in species composition and taxonomic structure. Replacement of species between sites was responsible for the presence of new functional groups of macroalgae. High β diversity and taxonomic similarity values were characteristic of the macroalgae of the Red Sea. The occurrence of small macroalgal thalli that have short life cycles induced high species replacement and subsequently high β diversity, with spatial heterogeneity and environmental gradient as drivers of β diversity. Anthropogenic disturbance at the Safaga site was suggested to induce variation of macroalgal assemblages and functional groups. Excluding rare species from the data set did not change the high values of b diversity.

β Diversity is an ecological concept used to describe the turnover of species across a wide range of spatial and temporal scales, but such knowledge is lacking for macroalgal assemblages of the Red Sea. β Diversity patterns for Red Sea macroalgae were evaluated from different sites (Hurghada, Safaga, and Al-Quseir) and seasons across different environmental disturbances. β Diversity was studied by partitioning the total number of species (γ diversity) into additive components. Geographical heterogeneity was more important than seasonal heterogeneity in structuring macroalgae both at species and functional group levels. Species replacement as a component of β diversity produced dissimilarity in species composition and taxonomic structure. Replacement of species between sites was responsible for the presence of new functional groups of macroalgae. High β diversity and taxonomic similarity values were characteristic of the macroalgae of the Red Sea. The occurrence of small macroalgal thalli that have short life cycles induced high species replacement and subsequently high β diversity, with spatial heterogeneity and environmental gradient as drivers of β diversity. Anthropogenic disturbance at the Safaga site was suggested to induce variation of macroalgal assemblages and functional groups. Excluding rare species from the data set did not change the high values of b diversity.