Mittal V.,Petroleum Institute Abu Dhabi
Polymer Engineering and Science | Year: 2017
Homogeneous multiwalled carbon nanotube/montmorillonite hybrid filler (HMM) dispersion was prepared by co-ultrasonication and was subsequently used to prepare ethylene-co-vinyl acetate (EVA) nanocomposites by solution blending method. XRD and TEM analysis of HMM confirm significant interaction between the montmorillonite (MMT) layers and multiwalled carbon nanotubes (MWCNT) in line with previous reports. Analysis of the nanocomposites shows the constituent fillers to be homogeneously dispersed in EVA matrix. Mechanical properties of neat EVA are remarkably improved with HMM content up to 3 wt% followed by reversion. Maximum improvement observed in tensile strength, elongation at break, and toughness are 424%, 109%, and 1122%, respectively. Results show maximum thermal stability at 4 wt% and best dielectric response at 1 wt% HMM content. Exceptional mechanical and dielectric properties of EVA nanocomposites attained may be attributed to homogeneous dispersion of fillers and improved polymer-filler interaction. Comparison shows excellent synergy between MWCNT and MMT towards mechanical reinforcement of EVA. © 2017 Society of Plastics Engineers.
Cuccu F.,University of Cagliari |
Emamizadeh B.,Petroleum Institute Abu Dhabi |
Porru G.,University of Cagliari
Applied Mathematics and Optimization | Year: 2010
This paper is concerned with minimization and maximization problems of eigenvalues. The principal eigenvalue of a differential operator is minimized or maximized over a set which is formed by intersecting a rearrangement class with an affine subspace of finite co-dimension. A solution represents an optimal design of a 2-dimensional composite membrane Ω, fixed at the boundary, built out of two different materials, where certain prescribed regions (patches) in Ω are occupied by both materials. We prove existence results, and present some features of optimal solutions. The special case of one patch is treated in detail. © 2010 Springer Science+Business Media, LLC.
Bener A.,Hamad Medical Corporation |
Bener A.,Petroleum Institute Abu Dhabi |
Bener A.,University of Manchester |
Saleh N.M.,Hamad Medical Corporation |
And 4 more authors.
Journal of the Pakistan Medical Association | Year: 2013
Objective: To examine socio-demographic and biological risk factors associated with mothers giving birth to a low birthweight newborn among Arab women in Qatar. Methods: The case-control study was conducted at two main tertiary hospitals in Qatar in which participants were prospectively identified from January 2010 to April 2011. Data were collected by survey on maternal ethnicity, age, education, socioeconomic status, body mass index, consanguinity and gestational age. A total of 16,500 newborns were screened for low birthweight. A total of 863 mothers of low birthweight cases and an equal number of mothers of normal-weight babies were studied. Results: Qatari mothers were found to be 1.2 times as likely to have a low birthweidht (<2500g) newborn compared to other Arab women (p<0.057). Mothers with a primary school education were 1.6 times as likely as university educated mothers to have a low birthweidht newborn (p<0.006). Likewise, obese mothers were 1.5 times as likely as their normal-weight counterparts (p<0.009). Consanguineous couples who were first-degree cousins were 1.9 times as likely as non-related couples to have a low birthweidht newborn (p<0.001). Newborns with a gestational age of <37 weeks were 19.6 times as likely as those ≥37 weeks to have a low birthweidht (p <0.001). Conclusion: The majority of the risk factors associated with low birthweidht were modifiable. Health education campaigns need to target the most vulnerable groups to reduce the rates of low birthweidht among Arabs in Qatar.
Jagannath A.,Petroleum Institute Abu Dhabi |
Almansoori A.,Petroleum Institute Abu Dhabi
AIChE Journal | Year: 2017
Hydrogen network design is an important step in hydrogen management of a petroleum refinery that manages the hydrogen distribution and consumption in a cost-effective manner. While most works in this area have primarily focused on minimization of fresh hydrogen requirement and hydrogen purification aspects, very few works have dealt the issue of compression costs in hydrogen network designs. This work proposes a new mathematical model for synthesizing a hydrogen network with minimum compression costs. In contrast to the existing literature, this model uses stream-dependent properties and realistic compressor cost correlations to determine the compression duty and costs, respectively. Tests on literature examples show that our model is flexible and gives reasonably favorable solutions than the previous models. Furthermore, the usefulness of understanding the trade-offs between the number of compressors and compression duty and the importance of using stream-dependent conditions in estimating compression costs are also highlighted in this work. © 2017 American Institute of Chemical Engineers.
Murawwi E.A.,Power Engineering and Commissioning TRANSCO |
Mohammed A.,Petroleum Institute Abu Dhabi |
Alip Z.,Petroleum Institute Abu Dhabi |
Ei-Hag A.,American University of Sharjah
2013 IEEE Electrical Insulation Conference, EIC 2013 | Year: 2013
In this paper, a corona ring design optimization for a 400kV non-ceramic insulator was investigated. Two parameters were changed during the study which are: the ring diameter (R) and the diameter of the ring tube (r). In this study, with the aid of a developed mathematical model the maximum electric field curves were recreated and an estimated electric field equation in terms of r and R while fixing H was found. Finally, using the estimated equation, a non-linear optimization technique was applied. The solution for this optimization problem gives the optimal dimensions of r and R as well as the ratio of R/r which will reduce the electric field value most effectively for a given constant cost. © 2013 IEEE.
Sethuraman K.,Anna University |
Vengatesan M.R.,Petroleum Institute Abu Dhabi |
Lakshmikandhan T.,Anna University |
Alagar M.,Anna University
High Performance Polymers | Year: 2016
In the present work, allyl-terminated benzoxazine and thiol-functionalized polyhedral oligomeric silsesquioxane (SH-POSS) were synthesized and their molecular structures were confirmed by Fourier transform infrared, proton nuclear magnetic resonance (NMR), carbon-13 NMR, and silicon-29 NMR spectroscopies. The PBZ hybrid composite materials were developed through photopolymerization (ultraviolet (UV) lamp) reactions of allyl-terminated benzoxazine monomer with different weight percentages of SH-POSS (P10, P30, and P50 wt%), followed by thermal curing. The data obtained from transmission electron microscopy and X-ray diffraction analysis infer the presence of homogeneous morphology of the cured samples. Data obtained from differential scanning calorimetry, thermogravimetric analysis, UV transmittance, dielectric, and contact angle studies indicate that the dual cured P50-PBZ hybrid composite exhibits higher thermal, UV shielding, and hydrophobic behavior and lower value of dielectric constant than those of lower weight percentages of SH-POSS reinforced hybrid composites. © SAGE Publications.
Hasan F.M.,Petroleum Institute Abu Dhabi |
Beig A.R.,Petroleum Institute Abu Dhabi
Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC | Year: 2013
The increasing use of power electronic system has led voltage harmonic distortion level to an unacceptable level at point of common coupling (PCC). Most of the modern solutions of eliminating load current harmonics by using active filter is based on sinusoidal source voltage. However, the voltage at PCC is not purely sinusoisdal. This paper proposes a shunt active filter (SAF) based on instantaneous active and reactive power theory which can mitigate the load harmonics properly even if the source voltage is distorted. Space vector PWM based voltage source inverter is used in current control mode to filter out current harmonics. PI controllers are used for the current controller to get desired dynamic response. The proposed algorithm is verified through simulation. Real life conditions are considered in the simulation and the simulation results are presented. © 2013 IEEE.
Parasuraman S.,University of Selangor |
Hou C.M.,University of Selangor |
Fok S.C.,Petroleum Institute Abu Dhabi
Conference Record - IEEE Instrumentation and Measurement Technology Conference | Year: 2011
The trajectory planning of kinematically redundant manipulator is a key area of research that requires efficient optimization algorithms. This paper presents a new method that combines multiple objectives for the trajectory planning of robots with redundant degrees of freedom. The proposed technique combines Genetic Algorithm (GA) with a collision detection scheme to find the shortest and smoothest trajectory for a robot to move from a given initial point to a target location while avoiding obstacles. The evaluation function is based on the total linear displacement of end-effector and total angular displacement of joints with uniformity Cartesian and joint space velocities. The proposed approach is analyzed with three different working environments and the results indicated that the scheme can perform as well if not better than the collision detection and target finding method. © 2011 IEEE.
Hafiz A.R.,Petroleum Institute Abu Dhabi |
Al-Marzouqi H.,Petroleum Institute Abu Dhabi
2016 IEEE 12th Image, Video, and Multidimensional Signal Processing Workshop, IVMSP 2016 | Year: 2016
Sparse representations for signals and images have been used extensively in various image processing tasks. In this work, we use the curvelet transform as a sparsity inducing tool in neural networks. Nowadays, there is much interest in research and development of efficient algorithms that reduce the computational demands of training neural networks. We demonstrate that the compact directional representation generated by the curvelet transform has the potential of significantly reducing computational time and costs. In our proposed classification framework, curvelet coefficients (amplitude and angle) are mapped into the complex domain. Next, a single-layer Complex-Valued Neural Network (CVNN) is used to represent the complex input parameters. After training the network using a suitable training dataset, computed complex weight vectors are used to classify testing datasets. The developed algorithm was tested on the MNIST dataset. Our results indicate a performance that is comparable with state-of-the-art while offering dramatic computational savings. © 2016 IEEE.
Shawon M.J.A.,Petroleum Institute Abu Dhabi |
Lamont L.,Petroleum Institute Abu Dhabi |
El Chaar L.,General Electric
Proceedings of the IASTED International Conference on Power and Energy Systems, EuroPES 2012 | Year: 2012
Standalone PV-Wind hybrid energy systems show higher reliability compared to Wind or PV standalone systems. This paper presents a Matlab/Simulink model of an integrated standalone PV-Wind hybrid system using a battery for storage and backup protection. The individual component of such system is discussed and modeled. Different control strategies are applied to ensure efficient and reliable power supply under various atmospheric and loading conditions.