Polarization Dynamics in Nonlinear Photonic Resonators

The global market demand for higher-bandwidth communication is increasing exponentially. Although optical networks provide high transmission speed using light to transmit signals, a bottleneck-inducing conversion is often needed to perform the processing of optical signals in the electrical domain. Such processing imposes a major barrier that would limit the high transmission speed of fiber-optic communications. This bottleneck conversion may be mitigated by extending signal-processing capabilities directly into the optical domain itself. Thus, I have studied the dynamics of optical polarization in a nonlinear photonic resonator to understand a new optical physical behavior to enhance the capabilities of optical signal processing. I present a theoretical model and experimental investigation to study the simultaneous occurrence of two optical nonlinear processes---nonlinear polarization rotation (NPR) and dispersive optical bistability. These two optical nonlinear processes within a nonlinear photonic resonator produce an optical signal exhibiting hysteresis curves in its state of polarization (SOP). Bistable action accompanied with simultaneous NPR is a significant departure from traditional optical memory, where the optical signal only exhibits hysteresis curves in the output power. Bistable polarization rotation (BPR) term is used to refer to the new physical process of bistable action accompanied by simultaneous NPR. I have leveraged this new physical process of the bistable polarization rotation to realize a hysteresis-shape transformation and optimization. A diversity of hysteresis shapes are demonstrated in optical power including the canonical counter-clockwise (CCW) shape (S-shape), the clockwise (CW) shape (inverted S-shape), and butterfly shapes. The control of the shape is performed downstream of the nonlinear photonic resonator within which the bistable signal is generated. I have derived a mathematical model to study this transformation process. Critical to our model, a generalized Malus\u27 law of a non-ideal linear polarizer and an elliptical input polarization. Since all hysteresis shapes originate from the same bistable signal, all shapes exhibit the same switching input powers. Moreover, the shape-control process is used to enhance the bistable switching contrast to surpass 20 dB for the CCW and CW shapes. Additionally, the new technique of hysteresis shape control enables the ability of simultaneous distribution of the bistable signal into multiple paths. In each path, the optical signal can be independently controlled to produce a hysteresis shape. For example, CCW and CW shapes can be configured in two locations using the same BPR signal. The theoretical and experimental work reported here is carried out for the case of a Fabry-Perot semiconductor optical amplifier as the nonlinear photonic resonator. Both the new physical process and the new control capability presented here are extendable to other nonlinear media (such as Kerr media) and other photonic resonators (such as ring and distributed feedback resonators). The dissertation outcomes detail processes and techniques to enhance the performance of all-optical combinational gates, such as photonic AND and XOR gates, as well as all-optical sequential devices, such as photonic flip-flops

Analytical approximate solutions for two-dimensional incompressible Navier-Stokes equations

Analytical approximate solutions of the two-dimensional incompressible Navier-Stokes equations by means of Adomian decomposition method are presented. The power of this manageable method is confirmed by applying it for two selected  flow problems: The first is the Taylor decaying vortices, and the second is the flow behind a grid, comparison with High-order upwind compact finite-difference method is made. The numerical results that are obtained for two incompressible flow problems  showed that the proposed method is less time consuming, quite accurate and easily implemented. In addition, we prove the convergence of this method when it is applied to the flow problems, which are describing them by  unsteady two-dimensional incompressible Navier-Stokes equations.   Keywords: Navier-Stokes equations, Adomian decomposition, upwind compact difference, Accuracy, Convergence analysis,Taylor's decay vortices, flow behind a grid

New analytical approximate solutions of Fifth-order KdV equation

In this paper, we have exposed a process of how to implement a new splitting Adomian decomposition homotopy perturbation method to solve fifth-order KdV equations. The new methodology is applied on two kinds of fifth-order KdV equations with initial data: The first is Sawada-Kotera equation and the second its Lax equation. The numerical results we  obtained  from solutions of two kinds of fifth-order KdV equations, have good convergent  and high  accuracy  comparison with other methods in literature. The graphs and tables of the new analytical approximate solutions show the validity, usefulness, and necessity of the process. Keywords: Splitting scheme, Adomian decomposition, homotopy perturbation method,  fifth-order KdV equation, convergence analysis. Mathematics Subject Classifications 2010 [MSC]: 76S05, 65N99, 35Q3

Splitting Decomposition Homotopy Perturbation Method To Solve One -Dimensional Navier -Stokes Equation

We have proposed in this  research a new scheme to find analytical  approximating solutions for Navier-Stokes equation  of  one  dimension. The  new  methodology depends on combining  Adomian  decomposition  and Homotopy perturbation methods  with the splitting time scheme for differential operators . The new methodology is applied on two problems of  the test: The first has an exact solution  while  the other one has no  exact solution. The numerical results we  obtained  from solutions of two problems, have good convergent  and high  accuracy   in comparison with the two traditional Adomian  decomposition  and Homotopy  perturbationmethods .&nbsp

Persistent Pneumothorax: Alveolar pleural fistula due to a hole in a bulla

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A New Technique for Simulation the Zakharov–Kuznetsov Equation

In this article, a new technique is proposed to simulated two-dimensional Zakharov–Kuznetsov equation with the initial condition. The idea of this technique is based on Taylors' series in its derivation. Two test problems are presented to illustrate the performance of the new scheme. Analytical approximate solutions that we obtain are compared with variational iteration method (VIM) and homotopy analysis method (HAM). The results show that the new scheme is efficient and better than the other methods in accuracy and convergence

Surrogate models to predict maximum dry unit weight, optimum moisture content and California bearing ratio form grain size distribution curve

This study evaluates the applicability of using a robust, novel, data-driven method in proposing surrogate models to predict the maximum dry unit weight, optimum moisture content, and California bearing ratio of coarse-grained soils using only the results of the grain size distribution analysis. The data-driven analysis has been conducted using evolutionary polynomial regression analysis (MOGA-EPR), employing a comprehensive database. The database included the particle diameter corresponding to a percentage of the passing of 10%, 30%, 50%, and 60%, coefficient of uniformity, coefficient of curvature, dry unit weight, optimum moisture content, and California bearing ratio. The statistical assessment results illustrated that the MOGA-EPR provides robust models to predict the maximum dry unit weight, optimum moisture content, and California bearing ratio. The new models’ performance has also been compared with the empirical models proposed by different researchers. It was found from the comparisons that the new models provide enhanced accuracy in predictions as these models scored lower mean absolute error and root mean square error, mean values closer to one, and higher a20−index and coefficient of correlation. Therefore, the new models can be used to ensure more optimised and robust design calculations

Determination of medical waste composition in hospitals of Sana'a city, Yemen

The composition analysis of medical waste is generally considered to be the fundamental information for the most basic steps in the development of a plan for solid hospitals waste management. The objectives of this study were to determine the quantity, generation rate, and the physical composition of medical waste generated in hospitals of Sana'a city, Yemen. This cross-sectional, descriptive study was conducted on the composition of hospital wastes generated in four governmental hospitals in Sana'a City. Purposive sampling was used in the selection of the hospitals, which included (Al-Thawra, Al-Kuwait, Republic, and Military). Results of this study showed that the daily average of the waste generated from the studied hospitals was 5615 kg/day. Approximately 26% of the total waste was hazardous (infectious, pathological, and chemical wastes). While 74% was a general (non-hazardous) waste. The average rate of the total waste generation was 3 kg/patient/day, and 2.5 kg/bed/day. The mean individual components of generated waste in the studied hospitals were; foods 27%, plastic 22%, paper/cardboard 22%, glass 11%, metals 10%, and others 8%. In conclusion, about 26% of the waste was hazardous. The physical component analysis of the waste indicated that the foods, plastic, and paper/cartoon has the highest content of the hospitals waste. Decision makers in Yemen can use this study information for designing and plan the properly management for the collecting system and the healthy disposal of the hazardous waste. Also, for estimating the total policy of required facilities, manpower, and other related costs.Keywords: Composition; medical waste; hospitals waste; Yeme

Natural and recycled materials for sustainable membrane modification: Recent trends and prospects

Despite water being critical for human survival, its uneven distribution, and exposure to countless sources of pollution make water shortages increasingly urgent. Membrane technology offers an efficient solution for alleviating the water shortage impact. The selectivity and permeability of membranes can be improved by incorporating additives of different nature and size scales. However, with the vast debate about the environmental and economic feasibility of the common nanoscale materials in water treatment applications, we can infer that there is a long way before the first industrial nanocomposite membrane is commercialized. This stumbling block has motivated the scientific community to search for alternative modification routes and/or materials with sustainable features. Herein, we present a pragmatic review merging the concept of sustainability, nanotechnology, and membrane technology through the application of natural additives (e.g., Clays, Arabic Gum, zeolite, lignin, Aquaporin), recycled additives (e.g., Biochar, fly ash), and recycled waste (e.g., Polyethylene Terephthalate, recycled polystyrene) for polymeric membrane synthesis and modification. Imparted features on polymeric membranes, induced by the presence of sustainable natural and waste-based materials, are scrutinized. In addition, the strategies harnessed to eliminate the hurdles associated with the application of these nano and micro size additives for composite membranes modification are elaborated. The expanding research efforts devoted recently to membrane sustainability and the prospects for these materials are discussed. The findings of the investigations reported in this work indicate that the application of natural and waste-based additives for composite membrane fabrication/modification is a nascent research area that deserves the attention of both research and industry

Calculating the Theoretical Octane Number for a Number of Petroleum Derivatives Using Quantum Mechanical Methods AM1 and PM3

This research included calculating a number of physical variables that affect the octane number using semi-empirical methods of quantum mechanics, including AM1, PM3, hardness (η), electron-chemical potential (µ), spherical electrophilic index (W, ∆G, ∆H, ∆S, ∆E and dipole moment). Multiple statistical analyses were used to find the relationship between the calculated variables and the practical value of the octane number and then calculate the octane number theoretically. Through the four-way statistical analysis, we obtained the best correlation coefficient (R2) for the variables (HOMO + η + ∆S + ∆E) calculated by the PM3 method (R2 = 0.998) and the correlation coefficient values for the variables (HOMO + η + W+ µ) calculated by the AM1 method (R2 = 0.980). Through the single and multiple statistical analysis, the most influential variables on the octane number values are (HOMO, LOMO)