Majid Khan Majahar Ali

The Cultivation of Kappaphycus and Eucheuma in Tropical and Sub-Tropical Waters

Kappaphycus and Eucheuma species have been successfully cultivated in Southeast Asia since the early 1970s. The increasing global demand for carrageenan in processed foods and thereby the need for industrial-scales of biomass to be provided to feed an extraction industry, exceeded wild stock availability and productivity and commercial demands could only be achieved through extensive cultivation of selected carrageenophytes. This unprecedented situation led to the introduction of carrageenophyte species and cultivars around the world; combined production of Eucheuma and Kappaphycus is one of the largest for seaweed biomass in the world.

Overview of Photovoltaic Thermal (PVT) Water Collector

Received May 21, 2018 Revised Aug 30, 2018 Accepted Sep 13, 2018 This paper presents a novel Stator Current based Model Reference Adaptive System (SC_MRAS) speed observer for high-performance Six Phases Induction Motor (SPIM) drives using linear neural network. The article aim is intended to improve performance of an SC_MRAS observer, which were presented in the literature. In this proposed scheme, the measured stator current components are used as the reference model of the MRAS observer to avoid the use of a pure integrator and reduce the influence of motor parameter variation. The adaptive model uses a two-layer Neural Network (NN) to estimate the stator current, which has been trained online by means of a Least Squares (LS) algorithm instead of uses a nonlinear Back Propagation Network (BPN) algorithm to reduce the complexity and computational burden, it also help to improve some disadvantages cause by the inherent nonlinearity of the BPN algorithm as local minima, two heuristically chosen parameters, initialization, and convergence problems, paralysis of the neural network. The adaptive model of the proposed scheme is employed in prediction mode, not in simulation mode as is usually the case in the literature, this made the proposed observer operate better accuracy and stability. In the proposed observer, stator and rotor resistance values are estimated online, these values thereafter were updated for the current observer and rotor flux identifier to enhance the accuracy, robustness and insensitivity to parameters variation for the proposed observer. The proposed LS SC_MRAS observer has been verified thought the simulation and compared with the BPN MRAS observer. The simulation results have proven that the speed is estimated a consequent quicker convergence, do not need the estimated speed filter, lower estimation errors both in transient and steady state operation, better behavior in low and zero speed operation. Keyword:Received Jun 7, 2018 Revised Jul 8, 2018 Accepted Sep 13, 2018 Experiments confirmed that Transformerless Inverters (TIs) deliver more reliability and higher energy efficiency. Nonetheless, one of the shortcomings of TIs is the leakage current that occurs between the photovoltaic (PV) string terminals and the ground. Such a drawback is justified by the non-galvanic isolation caused by the transformer being omitted. As such, this study is intended to develop a novel TI inverter topology for solar PV systems. The latter is meant to remove the leakage current and enhance the operating system of the entire PV conversion as well. Added to its null zero-crossing distortion and capability regarding energy efficiency, the developed TI, being validated by simulation and experiment, eradicated the leakage current. Keyword:Now a day’s renewable energy sources became an interesting area of research of which fuel cells are emerged as an alternative source for producing electricity to meet the energy crisis. This led to a research on power conditioning systems through which fuel cell is interfaced to the utility. Of the different converter topologies Isolated full bridge boost converter (IFBC) topology is most suitable for fuel cell applications. In this paper a Predictive Switching Modulator (PSM) Control is proposed for the converter topology and its performance is compared with Linear Peak Current Mode control (LPCM), Non-Linear Carrier Control (NLC).Received May 2, 2018 Revised Aug 23, 2018 Accepted Sep 14, 2018 Recently of the main topic of research is the sensorless vector control of induction motor drive, In this paper presents the predictive model reference adaptive system (PMRAS) rotor speed observer, This observer developed from the classical MRAS rotor flux scheme associated with predictive adaptation mechanism designed from the Finite Control Set Model Predictive Control (FCS–MPC) by using a search optimization algorithm for calculate the rotor position which guarantee a minimum speed tuning error signal at each sampling period. The effectiveness of the proposed observer proved with the simulation results, show high dynamic performance speed and position observed in sensorless vector control process at low and zero speed as well robustness against motor parameter variation with different loading conditions. Keyword:

Implications of drying temperature and humidity on the drying kinetics of seaweed

A Low Temperature and Humidity Chamber Test tested in the Solar Energy Laboratory, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor, Malaysia. Experiments are attempted to study the effect of drying air temperature and humidity on the drying kinetics of seaweed Kappaphycus species Striatum besides to develop a model to estimate the drying curves. Simple method using a excel software is used in the analysis of raw data obtained from the drying experiment. The values of the parameters a, n and the constant k for the models are determined using a plot of curve drying models. Three different drying models are compared with experiment data seaweed drying at 30, 40, 50 and 60°C and relative humidity 20, 30 and 40% for seaweed. The higher drying temperatures and low relative humidity effects the moisture content that will be rapidly reduced. The most suitable model is selected to best describe the drying behavior of seaweed. The values of the coefficient of determination (R2), mean bias error (MBE) and root mean square error (RMSE) are used to determine the goodness or the quality of the fit. The Page model is showed a better fit to drying seaweed. The results from this study crucial for solar dryer development on pilot scale in Malaysia.

Post-Harvest Handling of Eucheumatoid Seaweeds

The post-harvest handling of cultivated seaweed biomass is a crucial stage in the whole value-chain of the carrageenophyte industry. The quantity and quality of carrageenan derived from any given biomass depends largely on the post-handling treatment and management of the supply-chain for the harvested seaweeds. Since the successful farming of Kappaphycus and Eucehuma began in the early 1970s in the Philippines, the generally low technologies and cheaper conventional methods of drying the harvested seaweeds (i.e. hanging, platform, shade drying, ‘sauna-like method,’ etc.) are still prefered by the majority of farmers. However, these methods pose serious problems for carrageenophyte quality. A new day is coming when the traditional methods will not be sufficient in order to add value to the biomass. Recently, new methods for the drying of various eucheumatoid seaweeds were introduced, e.g. passive drying (chimney and greenhouse-based solar houses), active drying (de-humidifier drier) and hybrid (wind turbine, double-pass solar collectors with fins and v-groove, solar driers). However, these are still in their early stages of development and technology transfer to the industry.

Performance Analysis of Half-Sweep Successive Over-Relaxation Iterative Method for Solving Four-Point Composite Closed Newton-Cotes System

The theory and application of integral equations is an important subject within applied mathematics. Consequently, the main aim of this research paper is to investigate the performance of a variant of Successive Over-Relaxation iterative method i.e. Half-Sweep Successive Over-Relaxation (HSSOR) for solving four-point composite closed Newton-Cotes quadrature (4- CCNC) system that generated from linear Fredholm integral equations of the second kind. The numerical results from the simulations of the tested methods are presented.

Preconditioned Jacobi-type iterative methods for solving Fredholm integral equations of the second kind

In this paper, performance analysis of the preconditioned Jacobi-type iterative methods for solving linear system arise from Fredholm integral equations of the second kind is investigated. The formulation and implementation of the proposed methods are presented. Also, numerical results are included in order to verify the performance of the methods.

Performance analysis of 2-Point explicit group iterative methods for solving four-point composite closed Newton-Cotes system

In this paper, numerical solutions of second kind Fredholm integral equation on a bounded domain are considered. We convert the integral equation to a linear system by using four-point composite closed Newton-Cotes (4-CCNC) scheme. Then, the performance of 2-Point Explicit Group (2-EG) method with complexity reduction approach for solving the generated linear system is investigated. Numerical results by solving test problems are included to verify the performance of the proposed method.