University of Bahrain

About: University of Bahrain is a education organization based out in Madīnat ‘Īsá, Bahrain. It is known for research contribution in the topics: Thin film & Doping. The organization has 1650 authors who have published 3405 publications receiving 48162 citations. The organization is also known as: Bahrain University & UoB.

Simulation of the Process of Biological Removal of Hydrogen Sulfide from Gas

Abstract: Hydrogen sulfide (H2S) is considered as one of the most noxious industrial gases. Its removal from natural gas is particularly required for reasons of health, odour problems, safety and corrosivity problems. H2S causes an irritating, rotten egg smell in concentrations above 1 ppm, and at concentrations above 10 ppm the toxicological exposure limits are exceeded. Many methods have been developed over the years for the removal of H2S from gaseous emissions. H2S removal, with subsequent sulphur recovery, is at present mostly preferred using a train of Claus process, Tail Gas Treating Unit and Amine Treating Unit. Some of the disadvantages of these methods for gas treatment are that they require relatively large investment and operational costs (e.g. special chemicals, equipment corrosion, high pressures and temperatures) and they require special operational safety and health procedures. Continual search for more economical removal methods has led to investigations into microbiological solutions for H2S removal. One of the most common technologies for biological treatment of sour gas is the THIOPAQ™ process. It removes H2S from gaseous streams by absorption into a mild alkaline solution followed by oxidation of the absorbed sulfide to elemental sulphur by naturally occurring micro organisms. On the other hand, the Shell Claus Off-gas Treating (SCOT) process can be viewed as the industry standard classical process for small scale gas treatment. The purpose of this study is to simulate the biological oxidation of H2S gas process (THIOPAQ™) and SCOT process using the software HYSYS. In addition, these processes are compared qualitatively and quantitatively in terms of economic considerations. The comparison revealed that the biological process is safe, simple, and is cost competitive with respect to the SCOT process

Dynamic directional routing for mobile wireless sensor networks

Abstract: The interest in Mobile Wireless Sensor Networks (MWSN) has grown considerably due to its various applications in the fields of military, industrial infrastructure, automation, health, traffic, and many consumer areas. Hence, as the modern world shifting to the age of IoT with possibly new emerging technologies and applications, there will be a number of implications that influence the design and deployment of such networks. Precisely, residual energy utilization, mobility, topology, scalability, and data routing are key factors in the design of MWSN to meet application's specific demand. This article presents a novel routing protocol that adapt to the mobility of sensor nodes to achieve a reliable and energy-efficient routing. The proposed scheme is dynamic directional routing (DDR) to control the flow of data in network, which optimizes the routes toward the sink. The protocol has been evaluated and compared with state-of-art protocols, and the simulation results show that DDR protocol can improve network lifetime by around 13% compared to T-LEACH protocol. It also enhances the packet delivery rate, energy consumption, while maintain shorter routes toward the sink by around 33% compared to T-LEACH protocol.

Optimal control of UPFC for load flow control and voltage flicker elimination and current harmonics elimination

Abstract: Recent advances in the power system handling capabilities of static switches have made the use of the voltage source inverter (VSI) feasible at both transmission and distribution levels. Most of the control schemes introduced were designed either for eliminating current harmonics or eliminating voltage flickers or for load flow control. They are mostly based on the PI controller. None of these control schemes were based on a systematic optimal control law that can control the converters to achieve all purposes at the same time, load flow control, voltage flicker elimination and also current harmonics elimination. This paper presents three novel control strategies: optimal control with tracking according to desired steady-state behaviour, optimal control with linear quadratic tracker design, and optimal control with tracking with PI controllers. The strategies were tested using a power system distribution model. The presented results show that all three control strategies improve the performance of the load flow and eliminate the current harmonics and voltage flicker. The controller design based on the desired steady-state behaviour is superior compared to other way of designs as the low value of the weighting matrix Q is satisfactory to obtain the desired tracking.

Nonlinear Refractive Index Measurements and Self-Action Effects in Roselle-Hibiscus Sabdariffa Solutions

Abstract: We report the observation of self-action phenomena, such as self-focusing, self-defocusing, self-phase modulation and beam fanning in Roselle-Hibiscus Sabdariffa solutions. This material is found to be a new type of natural nonlinear media, and the nonlinear reflective index coefficient has been determined using a Z-scan technique and by measuring the critical power for the self-trapping effect. Z-scan measurements show that this material has a large negative nonlinear refractive index, n2 = 1 × 10−4 esu. A comparison between the experimental n2 values and the calculated thermal value for n2 suggests that the major contribution to nonlinear response is of thermal origin.

Parallel LOD methods for second order time dependent PDEs

Abstract: Time dependent problems in Partial Differential Equations (PDEs) are often solved by the Method Of Lines (MOL). In many important instances, the exact solution of the resulting system of Ordinary Differential Equations (ODEs) satisfies recurrence relations involving the matrix exponential function. This function is approximated by a new type of rational function possessing real and distinct poles which, consequently, readily admits a partial fraction expansion thereby allowing the distribution of the work in solving the corresponding linear algebraic systems in essentially Backward Euler-like solves on concurrent processors. Locally One Dimensional (LOD) splitting methods with enhanced parallelization are developed for multispace problems utilizing Strang-like splitting techniques. The use of rational approximants with distinct real poles in the temporal direction, in collusion with splitting techniques in the spatial directions, creates the potential for efficient coarse grain time-stepping parallel algorithms on MIMD machines. The resulting parallel algorithms possess appropriate stability properties, and are implemented on various parabolic and hyperbolic PDEs from the literature in higher space dimensional problems.