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Energy Efficient Design of a Jet Pump by Ensemble of Surrogates and Evolutionary Approach
Afzal Husain,Arihant Sonawat,Sarath Mohan,Abdus Samad 한국유체기계학회 2016 International journal of fluid machinery and syste Vol.9 No.3
Energy systems working coherently in different conditions may not have a specific design which can provide optimal performance. A system working for a longer period at lower efficiency implies higher energy consumption. In this effort, a methodology demonstrated by a jet pump design and optimization via numerical modeling for fluid dynamics and implementation of an evolutionary algorithm for the optimization shows a reduction in computational costs. The jet pump inherently has a low efficiency because of improper mixing of primary and secondary fluids, and multiple momentum and energy transfer phenomena associated with it. The high fidelity solutions were obtained through a validated numerical model to construct an approximate function through surrogate analysis. Pareto-optimal solutions for two objective functions, i.e., secondary fluid pressure head and primary fluid pressure-drop, were generated through a multi-objective genetic algorithm. For the jet pump geometry, a design space of several design variables was discretized using the Latin hypercube sampling method for the optimization. The performance analysis of the surrogate models shows that the combined surrogates perform better than a single surrogate and the optimized jet pump shows a higher performance. The approach can be implemented in other energy systems to find a better design.
Afzal, M.,Zahid, Saleem Asian Australasian Association of Animal Productio 2004 Animal Bioscience Vol.17 No.7
Effects of addition of a mycotoxin detoxifier in poultry feed were studied in broilers. Aflatoxins were present in the poultry feed as 28 ppb (normal feed), 78 ppb (contaminated feed) and 170 ppb (highly contaminated feed). The mycotoxin detoxifier was used in 3 concentrations i.e. 1, 3 and 5 kg/ton of feed. Aflatoxins reduced the body weight in broiler chicken and treatment of contaminated feed with low level of detoxifier improved the body weight equivalent to that of normal feed. Higher level of detoxifier proved better than lower level addition in alleviating the effects of highly contaminated feed. Addition of detoxifier also resulted in improvement of FCR to the level of normal feed. Antibody levels against Newcastle disease virus on day 28 of age were significantly lower in chicken fed on contaminated feed. Addition of detoxifier in feed improved the antibody levels in chicken. Mortality was highest in groups given contaminated feed throughout the study period of 7 weeks. Significant mortality was also observed in groups given highly contaminated feed for 2 weeks. Mortality in chicken given detoxifier added contaminated feed was lowest and similar to the group given normal feed. The study shows that mycotoxin detoxifier containing oxyquinol, dichloro-thymol and micronized yeast can effectively neutralize the ill-effects of aflatoxins in poultry feed.
Blue-Shifted Rogue Waves Generation in Normal Dispersion Fiber Laser
Afzal, Muhammad Imran,Alameh, Kamal,Yong Tak Lee IEEE 2015 IEEE photonics technology letters Vol.27 No.22
<P>In the presence of noise in normal dispersion fiber mode-locked lasers, dissipative resonance disappears, which leads to instability of spectral broadening and makes the asymptotic accumulation of energy impossible. We experimentally generate dissipative soliton molecules-like spectral peaks and rogue waves in the frequency domain in a self-mode-locked fiber laser. Due to noise in the initial triangular-shaped mode locked wave, these molecules are arranged in the form of lobes on the longer wavelength side, thus forming three virtual groups of soliton molecules. Further dissipative accumulation of power in the mode-locked wave ultimately leads to the formation of a blue-shifted group of three rogue waves, due to the effective fusion of adjacent soliton molecules. This is the first report of an experimental observation of blue-shifted and three rogue waves in a single experiment. The results have far reaching implications for experimentation with soliton collisions, optical rogue waves, and understanding of hydrodynamics.</P>
Efficient and Reliable MPEG-4 Multicast MAC Protocol for Wireless Networks
Afzal, Muhammad Khalil,Kim, Byung-Seo,Kim, Sung Won IEEE 2015 IEEE Transactions on Vehicular Technology VT Vol.64 No.3
<P>Multicasting is the transmission of data to a group of nodes identified by a single destination address. Furthermore, multicasting is considered as an appropriate transmission method for multimedia services. Multimedia applications are expected to become more prevalent over mobile ad hoc networks in the near future. Therefore, achieving reliability in multimedia communications is an important task. Video compression technologies are about reducing and removing redundant video data so that a digital video file can be effectively sent over a network. With modern compression standards, such as Moving Picture Expert Group 2 (MPEG-2), MPEG-4, and H.264, which is also known as advanced video coding MPEG-4 part 10, losses of different frames have different impacts on video quality. In this paper, we propose a leader-based reliable multicast medium-access control layer protocol for multimedia applications to enhance video quality. We present a Markov chain model and numerical formulation of our proposed protocol. Simulation results show that our proposed method is better than other protocols in terms of the number of decodable frames, peak signal-to-noise ratio (PSNR), and video quality.</P>
Afzal, Muhammad Raheel,Oh, Min-Kyun,Lee, Chang-Hee,Park, Young Sook,Yoon, Jungwon Hindawi Publishing Corporation 2015 BioMed research international Vol.2015 No.-
<P>Gait asymmetry caused by hemiparesis results in reduced gait efficiency and reduced activity levels. In this paper, a portable rehabilitation device is proposed that can serve as a tool in diagnosing gait abnormalities in individuals with stroke and has the capability of providing vibration feedback to help compensate for the asymmetric gait. Force-sensitive resistor (FSR) based insoles are used to detect ground contact and estimate stance time. A controller (Arduino) provides different vibration feedback based on the gait phase measurement. It also allows wireless interaction with a personal computer (PC) workstation using the XBee transceiver module, featuring data logging capabilities for subsequent analysis. Walking trials conducted with healthy young subjects allowed us to observe that the system can influence abnormality in the gait. The results of trials showed that a vibration cue based on temporal information was more effective than intensity information. With clinical experiments conducted for individuals with stroke, significant improvement in gait symmetry was observed with minimal disturbance caused to the balance and gait speed as an effect of the biofeedback. Future studies of the long-term rehabilitation effects of the proposed system and further improvements to the system will result in an inexpensive, easy-to-use, and effective rehabilitation device.</P>
Multiobjective Optimization of a Micromixer with Convergent–Divergent Sinusoidal Walls
Afzal, Arshad,Kim, Kwang-Yong Taylor Francis 2015 Chemical engineering communications Vol.202 No.10
<P>A multiobjective optimization of a micromixer with convergent-divergent sinusoidal walls has been conducted using flow and mixing analyses, surrogate modeling, and multiobjective genetic algorithm. The ratios of amplitude to wavelength of the sinusoidal walls, throat width to depth of the convergent-divergent sections, and diameter of the inner circular wall to wavelength were chosen as the design variables for optimization. The full-factorial method was used to discretize the design space. The mixing index and nondimensional pressure loss were selected as objective functions. Radial basis neural network functions were used to train the objective functions. The optimization was carried out at a Reynolds number of 30. A concave Pareto-optimal front representing the trade-off between the two objective functions was obtained. The analysis of representative designs along the Pareto-optimal front showed significant variation in the ratio of throat width to depth of the convergent-divergent sections, whereas the ratio of amplitude to wavelength of the sinusoidal walls maintained a nearly constant value. The concept of mixing effectiveness was used to select the most efficient designs considering both the mixing performance and pressure drop.</P>