Radzuan Razali

Data compression technique for modeling of global solar radiation

This paper studies the use of wavelet transform and curve fitting methods for solar radiation compression and prediction-based modeling. Symlet 6 and Meyer wavelets will be utilized for analyzing the transient nature of solar radiation. The measured solar radiation data will be decomposed up to level 4. After the data has been filtered, curve fitting method will be used to derive the modeling equation to estimate the horizontal global solar radiation. The instantaneous global solar radiation received on the surface of earth in Malaysia on a clear sky day around noon time can be up to 980 W/m2. The amount of solar energy received is highly transient in nature, due to the meteorological conditions. Therefore data captured using electronic data acquisition system is quite dense, and there is a need to filter the data, in order to reduce the amount of dataset. The data is highly useful for the designing of solar energy related electricity generation systems. The accuracy of the predicted output from a photovoltaic (PV) based electricity generation system depends on the accuracy of the intercepted solar radiation. The sizing of the electricity generating system cannot be based on a single power density value. Therefore compressed time based solar radiation values serve as an important input for the designing of a PV based system during the availability of sunshine.

Solar radiation data analysis by using Daubechies wavelets

The aim of this paper is to study the possibility of using wavelet transform method for solar radiation data compression. The Daubechies wavelets were utilized for analyzing the transient nature of solar radiation. The measured solar radiation was subjected to the wavelets techniques for smoothing and filtering of data that was decomposed up to level 5. The findings from this study show that the Daubechies wavelets method can be used for filtering and smoothing of solar radiation. The results presented indicate that Daubechies 10 (D10) wavelet approach is suitable for data filtering and smoothing of the solar radiation data.

A review of mathematical modeling and simulation of controlled-release fertilizers

ABSTRACT Nutrients released into soils from uncoated fertilizer granules are lost continuously due to volatilization, leaching, denitrification, and surface run‐off. These issues have caused economic loss due to low nutrient absorption efficiency and environmental pollution due to hazardous emissions and water eutrophication. Controlled‐release fertilizers (CRFs) can change the release kinetics of the fertilizer nutrients through an abatement strategy to offset these issues by providing the fertilizer content in synchrony with the metabolic needs of the plants. Parametric analysis of release characteristics of CRFs is of paramount importance for the design and development of new CRFs. However, the experimental approaches are not only time consuming, but they are also cumbersome and expensive. Scientists have introduced mathematical modeling techniques to predict the release of nutrients from the CRFs to elucidate fundamental understanding of the dynamics of the release processes and to design new CRFs in a shorter time and with relatively lower cost. This paper reviews and critically analyzes the latest developments in the mathematical modeling and simulation techniques that have been reported for the characteristics and mechanisms of nutrient release from CRFs. The scope of this review includes the modeling and simulations techniques used for coated, controlled‐release fertilizers. Graphical Abstract Figure. No caption available.

The Study of Biodegradation Kinetics of Starch Based on Coating in Controlled Released Fertilizer (CRF)

The aim of this study is to prepare a starch film and analyze its characteristics in different pH condition. Starch has been given great attention and has been actively investigated to be used as coating materials for CRF because of its degradation properties. Once the analysis on the starch characteristics is completed, the reaction rate of the starch can be developed by using Michaelis-Menten equation as reference. The results of the reaction rate are important to help determine the biodegradation kinetics of the starch. It will also assist in determining the conditions needed to produce the starch film in order to reduce the release rate of fertilizer. Throughout this study, the biodegradation kinetics of starch film will be investigated and thus providing a reference for the selection of coating material for the application of CRF while improving agriculture production.

Reaction-Multi Diffusion Model for Nutrient Release and Autocatalytic Degradation of PLA-Coated Controlled-Release Fertilizer

A mathematical model for the reaction-diffusion equation is developed to describe the nutrient release profiles and degradation of poly(lactic acid) (PLA)-coated controlled-release fertilizer. A multi-diffusion model that consists of coupled partial differential equations is used to study the diffusion and chemical reaction (autocatalytic degradation) simultaneously. The model is solved using an analytical-numerical method. Firstly, the model equation is transformed using the Laplace transformation as the Laplace transform cannot be inverted analytically. Numerical inversion of the Laplace transform is used by employing the Zakian method. The solution is useful in predicting the nutrient release profiles at various diffusivity, concentration of extraction medium, and reaction rates. It also helps in explaining the transformation of autocatalytic concentration in the coating material for various reaction rates, times of reaction, and reaction-multi diffusion. The solution is also applicable to the other biodegradable polymer-coated controlled-release fertilizers.

Bad data detection in power system state estimation based on generalized likelihood ratio test

The state estimator is a fundamental algorithm used in modern power industry to estimate the steady state of the system. The gross errors in input data of power system SE algorithm can considerably effect the accuracy of estimated measurements. Although, the commonly used state estimator algorithms utilize some statistical tests to detect the bad data, they are unable to properly deal with the gross errors with smaller magnitude and higher probabilities. This paper develops a new procedure based on the GLR test to effectively detect the bad measurements in the SE algorithm. The proposed strategy can detect, identify and to estimate the size of gross errors. This method is implemented on both single and multiple bad measurements cases to comparatively investigate the abilities of this algorithm. The obtained results confirm that the proposed algorithm has greater power of detecting and identifying the bad measurements compared to the estimator based on the conventional Chi-square and normalized residual te...

Curve fitting using logarithmic function for sea bed logging data

The aim of this research work is to conduct curve fitting using mathematical equations that relate location of the hydrocarbon (HC) at different depth to different frequencies. COMSOL MultiPhysics software was used to generate models of the seabed logging technique which consists of air, sea water, sediment and HC layer. Seabed Logging (SBL) is a technique to find the resistive layers under seabed by transmitting low frequency of EM waves through sea water and sediment. As HC is known to have high resistivity which is about 30-500Ωm, EM waves will be guided and reflected back and detected by the receiver that are placed on the seafloor. In SBL, low frequency is used to obtain greater wavelength which allows EM waves to penetrate at longer distance and each frequency used has different skin depth. The frequencies used in this project were 0.5Hz, 0.25Hz, 0.125Hz and 0.0625Hz and the depths of the HC were varied from 1000m to 3000m with increment of 250m. Data generated from the simulations using COMSOL software was extracted for the set up with and without HC and few trend lines were developed and R2 were calculated for each equation and curve. The calculated R2 were compared between data with HC to no HC at each depth and it was found that the calculated R2 values were very well fitted for deeper HC depth. This indicates that as depth of HC is higher, it is difficult to distinguish data with and without HC presence; and perhaps a new technique can be explored.The aim of this research work is to conduct curve fitting using mathematical equations that relate location of the hydrocarbon (HC) at different depth to different frequencies. COMSOL MultiPhysics software was used to generate models of the seabed logging technique which consists of air, sea water, sediment and HC layer. Seabed Logging (SBL) is a technique to find the resistive layers under seabed by transmitting low frequency of EM waves through sea water and sediment. As HC is known to have high resistivity which is about 30-500Ωm, EM waves will be guided and reflected back and detected by the receiver that are placed on the seafloor. In SBL, low frequency is used to obtain greater wavelength which allows EM waves to penetrate at longer distance and each frequency used has different skin depth. The frequencies used in this project were 0.5Hz, 0.25Hz, 0.125Hz and 0.0625Hz and the depths of the HC were varied from 1000m to 3000m with increment of 250m. Data generated from the simulations using COMSOL soft...

A Simulation Study on Factors Affecting Airwaves Using Factorial Design

In shallow water Sea Bed Logging (SBL) survey, air layer response from the Electro-Magnetic (EM) signals creates a disturbance known as the source-induced airwaves. The airwaves commonly denote the energy that propagates from the EM source via the atmosphere to the receiver on the seabed. As a result, the airwaves dominate the measured survey data, so that the sought-after signals from possible hydrocarbon layers in the subsurface can be totally masked. In this study, a 5x5 factorial design is used to analyze the effect of frequency, seawater conductivity, sediment conductivity, seawater depth and offset on the magnitude of airwaves. The result based on F-statistics, indicates that frequency has higher significant effect on the magnitude of the airwaves followed by the seawater depth, offset, seawater conductivity and sediment conductivity in that order.

Sea bed logging applications: ANOVA analysis for synthetic data from electromagnetic (EM) simulator

The aim of this research is to determine the significance level of parameters such as sediment thickness, frequency and step size for data generated from electromagnetic (EM) simulator for sea bed logging application that have been processed using cubic spline interpolation using ANOVA method. In this work synthetics data are generated from in house built simulator that is able to replicate sea bed logging environment. Sea bed logging (SBL) is a technique of finding resistive layers under sea bed by transmitting low frequency EM waves through sea water and sediment. Hydrocarbon is known to have high resistivity, about 30 - 500 Ωm and EM wave will be guided and reflected if there is hydrocarbon reservoir in the sediment. In SBL low frequency is used to obtain greater wavelength for longer wave penetration. In this work frequency used are 0.5Hz, 0.25Hz, 0.125Hz and 0.0625Hz and sediment thickness are varied from 1000m to 3000m incremented every 250m. Data collected are interpolated using cubic spline with s...

Analytical solution of diffusion model for nutrient release from controlled release fertilizer

An analytical method has been developed to solve the initial value problem which arises from Ficks diffusion equation encountered in the modelling of the Controlled Release Fertilizers. The proposed analytical solution is developed using the modified Adomian decomposition method. This method does not require the discretization method, reliability and efficiency of this method is more and it also reduces the calculation time. The model has predicted the effect of granule radius and diffusion coefficient on the nutrient release and total release time of Controlled Release Fertilizer. Model has predicted that increase in the radius of granule reduces the release and vice versa in case of diffusion coefficient. Detailed understanding of these parameters helps in improved designing of Controlled Release Fertilizer.