Abstract : The lack of clean water is one of the key issues facing the world today. The water in many countries is of poor quality, creating a big demand for bottled water, which has led to the deaths of millions in underdeveloped countries. Accordingly, there have been some efforts to develop an applicable technology known as Atmospheric Water Generators. It utilizes the natural occurrence of water vapour in the air to generate fresh water. This paper aims to solve the water crisis by designing an atmospheric water generator capable of supplying clean water that could be scaled up by an easy incremental expansion. An investigation has been conducted into different technologies of atmospheric water generators to address this issue. It could be concluded that desiccants are the most suitable technique to generate water with very low energy consumption and low cost. Additionally, an experiment has been conducted to select the most suitable concentration of the composite desiccant silica gel-CaCl2 concerning the absorption and regeneration capabilities, revealing that a 50% concentration is the best. This paper proposes a single-shelf triangular prism solar collector system that was manufactured and tested using silica gel-CaCl2 with a 50% concentration. The prototype resulted in producing 440 ml/m2/day. Also, the parameters affecting the process have been studied. Furthermore, a sample of water has been tested and proved that the extracted water meets the water quality international standards. Finally, the cost per litre was calculated and found to be 2.186 LE/litre (0.12 USD/litre)..
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The investigation of the existence of chaotic spiking in the dynamics of a semiconductor laser with an optical feedback was demonstrated theoretically by laser rate equations that describe the temporal variation of photon density and carrier density. The influence of changing the bias current on nonlinear dynamic are studied and the bifurcation diagram is achieved as a function of this parameter. Chaos synchronization between two distinct chaotic systems with independent initial conditions when add a common bias current is also considered.

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Abstract : In this study, the hydroxyapatite powder is investigated for the removal of methylene blue in aqueous solution. The physical and chemical properties of the adsorbent were evaluated systematically using the different techniques including Microsoft Excel programming, linear regression model and also the coefficient of determination. The adsorption kinetic parameters confirmed the better fitting of pseudo-second order kinetic model for methylene blue dye. The best parameters for the adsorption process were also studies as pH, time, dye concentration and the adsorbent dose. It is found that the maximum adsorption of methylene blue dye was at 120 min, pH of 4, dye concentration of 0.35 ppm and finally the best adsorbent dose of 0.35g. The maximum adsorption capacity (KF) of methylene blue is found to be 0.2736 (L/mg). Adsorption kinetics data were modeled with the application of Pseudo first order and Pseudo second order models. The results revealed that the Pseudo second order model was the best fitting model..
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Abstract : This article designs a dual transformer, which can be coupled or tuned to two arbitrary frequencies. We formulate this problem as a minimization problem of the Reflection Coefficient Γ_in, which allows us to find the impedances Z_1 and Z_2=Z_o R_l/Z_1 of the sections of the transmission line. We use Convex Optimization and the Dichotomous Search algorithm that allows us to find the parameters of the transmission lines. We show several results, and we include the case for operating frequencies of 700MHz (Band 7 - LTE) and 1900MHz (Band 2 -LTE)..
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Abstract : Augmentative and Alternative Communication (AAC) Mobile Applications are modern tools that enable individuals who have a difficulty or are not able to speak, a way to communicate the individual’s needs, wants, and expressions. There are AAC applications suited for individuals with Autism Spectrum Disorder (ASD), which use text and words, or symbols to represent specific words. These can be useful and effective for some individuals with ASD, however, there are individuals with ASD that may not be familiar or may not be able to comprehend text-based or symbol-based AAC mobile applications. This research will cover the development of an Augmentative and Alternative Communication (AAC) android mobile application that can use real life imagery to represent communication items, specifically for non-verbal and minimally verbal individuals with Autism, that aims to help the user to easily identify communication items and allow the individual to communicate effectively..
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