This paper proposes an adaptive transmission modulation (ATM) technique for free-space optical (FSO) links over gamma-gamma turbulence channels.The ATM technique provides efficient utilization of the FSO channel capacity for improving spectral efficiency, by adapting the order of the phase-shift keying modulation scheme, according to the channel conditions and the required bit error rate (BER). To overcome the channel degradation resulting from the turbulence effects as well as the pointing errors (PEs), single-input multiple-output (SIMO) system with maximal ratio combining (MRC) is proposed

The current work is concerned with the study of wave propagation in a half-space of a piezo-thermoelastic material under a bias tangential magnetic field within dual-phase-lag (DPL). This is relevant to the design and performance of piezoelectric devices working under a bias magnetic field, for example, the DC magnetic field piezoelectric sensors widely used in various areas of technology. The characteristic time for the problem under consideration is in the range of picoseconds, which is comparable to the thermal relaxation times in many metals. Exact analytic expressions for the mechanical

We investigate linear, thermoelastic wave propagation in a layered piezoelectric material composed of a slab bonded to a half-space substrate of a dissimilar material, within dual-phase-lag model and under thermomechanical loads. One of the aims of the present work is to formulate a set of boundary conditions that is compatible with the field equations. Normal mode technique is used to obtain a solution to the considered problem. The model allows for a jump in temperature at the interface, and this can be used to evaluate a material constant of the slab. It turns out, particularly, that a

In this paper the activated sludge wastewater treatment process is modeled mathematically and explored. In addition, irrigation was recommended as a valid application for the reuse of wastewater. Other wastewater treatment processes (WWTP) were compared to the one chosen to justify the choice and a detailed expiation of the general wastewater treatment process was provided. Furthermore, PI, and PID controller were developed to further improve the performance of the activated sludge process. The controllers were devolved and tuned using MATLAB, and SIMULINK, and had a positive correlation on

Plasmonic photovoltaics (PVs) are promising structures that improve thin-film photovoltaics performance, where optical absorption is improved via embedding metallic nanoparticles in the PV's active layer to trap the incident optical wave into the photovoltaic cell. The presented work investigates the design of PV with both structures of conical and cylindrical metallic nanoparticles through studying their extinction cross-sections and electric field distributions. Also, the impact of these nanoparticles in silicon PVs on the optical absorption enhancement is investigated. The figure of merit

Synthetic plastics are extensively used in several applications including packaging, containers, bottles, trays, and boxes. However, these plastics are based on synthetic components which are not biodegradable, thus they rigorously effect the environment causing water, air pollution and high health risks. Moreover, Individuals are exposed to chemicals during manufacturing or usage of synthetic plastic that can easily migrate to the surrounding such as styrene from polystyrene, plasticizers from polyvinyl chloride (PVC), antioxidants from polyethylene, and acetaldehyde from polyethylene

The aim of this paper is to develop a functional approach to optimize the engagement effectiveness of the tactical homing missiles and air defense systems by utilizing the differential geometric concepts. In this paper the engagement geometry of the interceptor and the target is developed and expressed in differential geometric terms in order to demonstrate the possibilities of the impact triangles and specify the earliest interception based on the direct intercept geometry. Optimizing the missile heading angle and suitable missile velocity against the target velocity is then examined to

The proposed correspondence between the Hawking-Unruh radiation mechanism in rotating, electrically-charged, and electrically-charged-rotating black holes and the hadronization process in high-energy collisions is assumed here. This allows us to determine the well-profound freezeout parameters characterizing the heavy-ion collisions. Furthermore, black holes thermodynamics is found analogous to a to that of the high-energy collisions. We also introduce a relation expressing the dependence of the angular momentum and the angular velocity deduced from rotating black holes on the chemical

Abstract: Based on statistical thermal approaches, the transverse momentum distribution of the well-identified produced particles, π+, π–, K+, K–, p, and (Fromula presented.), is studied. We aim at introducing a novel almost entirely empirical estimation for the inclusive chemical potential μ. From the partition function of a grand-canonical ensemble, we propose a generic expression for the dependence of μ on the rapidity y. Then, by fitting this expression with the experimental results of the most central p⊥ and d2N/2πp⊥dp⊥dy, at 7.7, 11.5, 19.6, 27, 39, 130, 200 GeV, we introduce a generic

Dissolved oxygen (DO) is an important water quality parameter. It is considered the most important parameter. DO concentration in water is affected by different parameters such as volume flow rate, water velocity, and re-aeration rate. Those parameters are directly affected by the geometry of the waterway. Thus, studying the impact of changing channel geometry on DO is very important. Many researchers studied the effect of influential parameters on water quality variables but the influence of channel geometric parameters on DO was not studied thoroughly before. This research aims to study the