A sub-regional outlook of renewable energy potential: the case of Jordan, Syria and Lebanon

This paper addresses the current status and the potentials of renewable energy applications in the selected Middle East countries; Jordan, Syria, and Lebanon. The energy and environmental situations within these primary target areas reflect many similarities and share serious common problems. These include an almost total dependence on imported oil products as the primary energy source, rapidly growing populations that are escalating the demand for energy, and only rudimentary efforts currently underway to mitigate the greenhouse and other adverse environmental effects of energy utilization. Lebanon is highly urbanized compared to Syria and Jordan with much smaller area and has not been fully engaged in pilot projects for use of renewable energy. Applications of solar energy in that region have been growing since 1970. Solar water heating with support of policies in Jordan has achieved measurable market penetration. Lebanon and Syria have not made reasonable progress in solar applications due to subsidized electricity supply to the end user. The technical and economic feasibility of wind energy utilization in Lebanon has not been yet fully explored, while it has advanced with two operating wind farms in Jordan, and one pilot wind farm in Syria. Similarly, the transfer of biomass technology has been successful in Jordan while it remains at the assessment level in Lebanon and Syria coupled with small pilot projects

Adaptive Grid Solution Procedure for Elliptic Flows.

This thesis deals with the formulation of a computationally efficient adaptive grid system for two-dimensional elliptic flow and heat transfer problems. The formulation is in a curvilinear coordinate system so that flow in irregular geometries can be easily handled. An equal order pressure-velocity scheme is formulated in this thesis to solve the flow equations. An adaptive grid solution procedure is developed in which the grid is automatically refined in regions of high errors and consecutive calculations are performed between the coarse grid and adapted grid regions in the same spirit as that of a Multi-Grid method. In orthogonal coordinate systems, checkerboard pressure and velocity fields are avoided by using staggered grids. In curvilinear coordinates however, the geometric complications associated with staggered grids are overwhelming and therefore a non-staggered grid arrangement is desirable. To this end, an equal order pressure-velocity interpolation scheme is developed in this thesis. This scheme is termed as the SIMPLEM algorithm and is shown to have good convergence characteristics, and to suppress checkerboard pressure and velocity fields. The adaptive grid technique developed flags the important regions in the calculation domain from an initial coarse grid calculation. Then, adaptation is performed by generating a nonuniform mesh in the flagged region using Poisson\u27s equations in which the nonhomogeneous terms are chosen so that a denser clustering of grid points is obtained where needed most in the flagged region. Coarse grid calculations in the whole domain, and fine grid calculations in the flagged region are consecutively performed until convergence, with correction terms from the fine grid solution added to the coarse grid equations in the flagged region in every cycle of calculation. Thus, the solution in the non-refined regions improves due to the influence of the correction terms added to the coarse grid equations. The effectiveness of the method is demonstrated by solving a variety of test problems and comparing the results with those obtained on a uniform or fixed grid. The adaptive grid solutions are shown to be more accurate than the fixed uniform grid solutions for the same level of computational effort

Numerical simulation of a collapsing bubble subject to gravity

© 2016 AIP Publishing LLC. The present paper focuses on the simulation of the expansion and aspherical collapse of a laser-generated bubble subjected to an acceleration field and comparison of the results with instances from high-speed videos. The interaction of the liquid and gas is handled with the volume of fluid method. Compressibility effects have been included for each phase to predict the propagation of pressure waves. Initial conditions were estimated through the Rayleigh Plesset equation, based on the maximum bubble size and collapse time. The simulation predictions indicate that during the expansion the bubble shape is very close to spherical. On the other hand, during the collapse the bubble point closest to the bottom of the container develops a slightly higher collapse velocity than the rest of the bubble surface. Over time, this causes momentum focusing and leads to a positive feedback mechanism that amplifies the collapse locally. At the latest collapse stages, a jet is formed at the axis of symmetry, with opposite direction to the acceleration vector, reaching velocities of even 300 m/s. The simulation results agree with the observed bubble evolution and pattern from the experiments, obtained using high speed imaging, showing the collapse mechanism in great detail and clarity

The aincient city of Lebanon Byblos

древние города, Библос, история, восток, Лива

Simulation of bubble expansion and collapse in the vicinity of a free surface

The present paper focuses on the numerical simulation of the interaction of laser-generated bubbles with a free surface, including comparison of the results with instances from high-speed videos of the experiment. The Volume Of Fluid method was employed for tracking liquid and gas phases while compressibility effects were introduced with appropriate equations of state for each phase. Initial conditions of the bubble pressure were estimated through the traditional Rayleigh Plesset equation. The simulated bubble expands in a non-spherically symmetric way due to the interference of the free surface, obtaining an oval shape at the maximum size. During collapse, a jet with mushroom cap is formed at the axis of symmetry with the same direction as the gravity vector, which splits the initial bubble to an agglomeration of toroidal structures. Overall, the simulation results are in agreement with the experimental images, both quantitatively and qualitatively, while pressure waves are predicted both during the expansion and the collapse of the bubble. Minor discrepancies in the jet velocity and collapse rate are found and are attributed to the thermodynamic closure of the gas inside the bubble

Veterinary education in Lebanon

Lebanon, veterinary education, Ливан, ветеринарное образование, зарубежный опы

Automated stock price prediction using machine learning

Thesis. M.S. American University of Beirut. Department of Computer Science, 2019. T:7122.Advisor : Dr. Wassim El Hajj, Associate Professor, Computer Science ; Members of Committee : Dr. Mohamad I Jaber, Associate Professor, Computer Science ; Dr. Haidar Safa, Professor, Computer Science.Includes bibliographical references (leaves 67-68)The financial market is a dynamic and composite system where people can buy and sell currencies, stocks, equities and derivatives over virtual platforms supported by brokers. The stock market – also known as the equity market – is considered one of the most dynamic components of the free-market economy. It allows investors to own shares in public companies through trading, either by exchange or over-the-counter markets. Thus, giving them the opportunity to make money by investing small amounts of capital which makes for a low-risk endeavor (initially at least), as opposed to opening a new business. Stock markets are however affected by a multitude of factors, making them uncertain and volatile. Which is why we have invested enormous amounts of time and effort trying to predict stock price movements, for by understanding those complex movements can be highly rewarding. Humans are capable of taking orders and submitting them to the market, but automated trading systems (ATS) on the other hand – implemented via a computer program – can perform quite better and with higher momentum when submitting orders. In order to evaluate and control the performance of these ATSs however, risk strategies and safety measures must be implemented; strategies that are based on human judgement. Many factors are incorporated and considered when developing an ATS, for instance, trading strategy to be adopted, complex mathematical functions that reflect the state of a specific stock, machine learning algorithms that enable the prediction of the future stock value, specific news related to the stock being traded, and so on. In order to predict market movements, investors traditionally analyzed stock prices and indicators, in addition to news about these stocks – the latter being of utmost importance when trying to understand stock price movements. Most of the previous work in this industry has focused either on labeling the released market news (positive, negative, neutral) and showing their effect on

Parametric Investigations of the Induced Shear Stress by a Laser-Generated Bubble

The present paper focuses on the simulation of the growth and collapse of a bubble in the vicinity of a wall. Both liquid and gas phases are assumed compressible, and their interaction is handled with the volume-of-fluid method. The main interest is to quantify the influence of the induced shear stress and pressure pulse in the vicinity of the wall for a variety of bubble sizes and bubble–wall distances. The results are validated against prior experimental results, such as the measurements of the bubble size, induced pressure field, and shear stress on the wall. The simulation predictions indicate that the wall in the vicinity of the bubble is subjected both to high shear stresses and large pressure pulses because of the growth and collapse of the bubble. In fact, pressure levels of 100 bar or more and shear stresses up to 25 kPa have been found at localized spots on the wall surface, at the region around the bubble. Moreover, the simulations are capable of providing additional insight to the experimental investigation, as the inherent limitations of the latter are avoided. The present work may be considered as a preliminary investigation in optimizing bubble energy and wall generation distance for ultrasound cleaning applications

Perforated Duodenal Diverticulum Treated Conservatively: Another Two Successful Cases

Diverticula of the duodenum proceed those of the colon in respect to frequency of location. Incidence at times of autopsy ranges from 15 to 23%. Despite the fact that more than 90% of duodenal diverticulum cases are asymptomatic, complications if they do occur can be calamitous. Perforation is one of these rare complications. Surgical intervention has always been the mainstay for symptomatic/complicated duodenal diverticula, but with the advancement of imaging, medical treatment, and proper intensive observation, conservative treatment came forth. We hereby present two cases of duodenal diverticula, complicated by perforation and fistulization into the retroperitoneal cavity, both treated conservatively by Taylor’s approach of upper gastrointestinal tract perforation. Review of other cases of duodenal diverticulum perforation has also been presented

A fully coupled navier-stokes solver for fluid flow at all speeds

This article deals with the formulation and testing of a newly developed, fully coupled, pressure-based algorithm for the solution of fluid flow at all speeds. The new algorithm is an extension into compressible flows of a fully coupled algorithm developed by the authors for laminar incompressible flows. The implicit velocity-pressure-density coupling is resolved by deriving a pressure equation following a procedure similar to a segregated SIMPLE algorithm using the Rhie-Chow interpolation technique. The coefficients of the momentum and continuity equations are assembled into one matrix and solved simultaneously, with their convergence accelerated via an algebraic multigrid method. The performance of the coupled solver is assessed by solving a number of two-dimensional problems in the subsonic, transsonic, supersonic, and hypersonic regimes over several grid systems of increasing sizes. For a desired level of convergence, results for each problem are presented in the form of convergence history plots, tabulated values of the maximum number of required iterations, the total CPU time, and the CPU time per control volume. © 2014 Taylor & Francis Group, LLC