Université de Technologie et de Sciences Appliquées Libano-Française

MANAGEMENT OF SPINAL DURAL ARTERIOVENOUS FISTULA, A REVIEW WITH ONE CASE REPORT Mohamed El Husseini@, Hussein Mouawia#, Adnan Mrad$ & Taghrid Chaaban* @MD, PhD, Neurosurgeon, Hôpital Libano Français, Zahle, Lebanon. #Director, Lebanese University, 4th Branch, Lebanon. $Dean, Islamic University of Beirut. *Vice dean, Islamic University of Beirut, Lebanon. Abstract Spinal dural arteriovenous fistulas (SDAVFs) are rare acquired vascular malformations of the spinal cord which if not treated properly, can lead to inevitable severe morbidity with progressive spinal cord symptoms. The management is still at high interest among specialists. If microsurgical treatment is still considered as a treatment of choice for SDAVFs, endovascular treatment is increasingly growing in interest with the development of endovascular techniques and new embolization materials. In this article, a short discussion is made about the spinal dural arteriovenous fistulae in respect to anatomy, etiology, diagnosis and treatment. Careful patient selection, a multidisciplinary approach and standardized surgical techniques can lead to excellent results with virtually no complications.

One-way carsharing system is a mobility service that offers short-time car rental service for its users in an urban area. This kind of service is attractive since users can pick up a car from a station and return it to any other station unlike round-trip carsharing systems where users have to return the car to the same station of departure. Nevertheless, uneven users’ demands for cars and for parking places throughout the day poses a challenge on the carsharing operator to rebalance the cars in stations to satisfy the maximum number of users’ requests. We refer to a rebalancing operation by car relocation. These operations increase the cost of operating the carsharing system. As a result, optimizing these operations is crucial in order to reduce the cost of the operator. In this paper, the problem is modeled as an Integer Linear Programming model (ILP). Then we present three different car relocation policies that we implement in a greedy search algorithm. The comparison between the three policies shows that car relocation operations that do not consider future demands do not effectively decrease rejected demands. On the contrary, they can generate more rejected demands. Results prove that solutions provided by our greedy algorithm when using a good policy, are competitive with CPLEX solutions. Furthermore, adding stochastic modification on the input data proves that the results of the two presented approaches are highly affected by the input demand even after adding threshold values constraints.

In this paper, a centralized model predictive control (MPC) is applied on a group of interconnected microgrids (MGs) with the main grid. The objective is to maximize the benefits for all the elements constituting the MGs in addition to the benefits of the main grid. The application of MPC in our study needs a forecasting information about energy prices, production power, and loads. The algorithm is tested on five interconnected MGs connected to the main grid. Results have shown the performance of the proposed algorithm, especially for the benefits of MG owners, the coordination between MGs while respecting of the constraints related to each one of them.

Antennas are becoming crucial in an increasingly growing number of vital applications, particularly with the emergence of the 3G and 4G generations of communications. Point-to-multipoint configuration is a major interest nowadays; therefore antennas are designed for this purpose where efficiency, size, and cost play a decisive role. The common practice is to refer to the already existing antennas in the market for this sole purpose. Nonetheless, a major drawback of such solutions is that the aforementioned criteria are extremely hard to simultaneously optimize. The purpose of this project is to present a new configuration relying on the use of Slotted Circular Waveguide Antennas, which are initially used in Radar applications, as an ultimate alternative that allows drastically enhancing the ratio of performance versus cost. Moreover, the antenna will be remodeled and designed to function as an enhanced Circular Slotted Waveguide Antenna with optimized directional characteristics with gain above 10 dBi (to be considered as high gain). Simulation results were carried out at 2.4 GHz frequency and indubitably demonstrated high effectiveness in terms of directivity and high gain given a reduced cost, shape and size. A prototype was fabricated to measure its parameters and compare them with simulation results. It is still noteworthy to mention that these results matched with an elevated accuracy since the pattern simulated is meshed and modeled to a far extent taking into account all non-ideal characteristics.

For industrial applications, microwave heating is an important technique. However, the homogenization problem must be taken into account to obtain rapid and reliable processes. Some industrial microwave heating systems are complex and expensive. In this paper, we propose a simple technique which use a cavity excited by a linear or a circular electric field polarization. A better microwave heating homogenization is obtain on ferrite and ethanol samples when the circular polarization is used. A specific test bench was made to perform temperature measurements on several sample points.

This paper deals with the simulation of off-road robots while taking into account the mechanical behavior of the locomotion system and its interaction with its environment. This interaction is studied and discussed for different behaviors of wheel-soil contact. The analysis considers phenomena of slips, of soil shear deformations, of soil compaction and wheel elastic deformation. Wheel-soil contact models are expressed by analytical relationships which link each contact force components (radial, longitudinal and lateral forces) to relative displacements (radial displacement, longitudinal slip ratio and side slip angle). These laws are then coupled to the dynamic equations of the mechanical system in order to characterize the behavior of the whole system. These models are implemented on a graphic simulation system which provides a basic tool for the design of the mechanical system, for the path planning and for the definition of control schemes.

Nous avons pu à partir du critère thermodynamique π volt-calories et de la relation linéaire existant entre l'enthalpie libre de formation et le nombre de ligands nNH3 existant dans les complexes aminés du cuivre, déterminer la valeur exacte de l'enthalpie libre de formation des ions Cu(NH3)42+. La valeur ainsi établie est en excellent accord avec les considérations analytiques mais elle diffère notablement de la valeur classique donnée par LATIMER.