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Articles by Hafizan Juahir
Total Records ( 4 ) for Hafizan Juahir
  Mohd Ekhwan Toriman , Norbaya Hashim , Abd. Jalil Hassan , Mazlin Mokhtar , Hafizan Juahir , Muhamad Barzani Gasim and Md Pauzi Abdullah
  This study on water quality modelling in Sungai Juru, Penang was undertaken as one of the most polluted rivers in Malaysia and is literally known as the ‘dying river’. The research objectives are to assess the parameters that govern the amount of pollutants in the river and to identify appropriate measures to improve the river water quality. The main pollution sources are pig waste, discharge from agro-based industries, dumping of municipal and industrial waste. Due to its relatively flat bed gradient, Sungai Juru experienced tidal effect up to a distance of 13 km from the estuary. As a result, pollutants in the river are hardly discharged into the sea. This research on Dissolved Oxygen (DO) parameter has been carried out to develop a rehabilitation solution for Sungai Juru by using the numerical hydrodynamic modeling technique simulated by I-D Infoworks R.S software. The modeling involved two phases namely, development of a flow model followed by a water quality model. After the model has been successfully calibrated, the pollutant behaviour under various scenarios can be investigated. The hydraulic study of Sungai Juru revealed that the velocity at STJ02 ranging from -0.1 to +0.12 m sec-1 during high and low tide, respectively. Based on this velocity, traveling time from S TJ02 (Sungai Juru) to STJ01 (Sungai Rambai) (3.5 km) is approximately between 9-10 h. The duration provides ample time for photosynthesis to occur resulting high DO ranging from 4-10 mg at STJ01. The information is useful to determine pollution characteristics in Sungai Juru particularly related to tidal impacts. It is hoped that the modeling technique developed can be applied in other rivers in Malaysia which are subjected to tidal influences.
  Usman Nasiru Usman and Hafizan Juahir
  Understanding the most effective pollutants affecting groundwater quality is of utmost importance in promoting sustainable development of groundwater resource. The study was performed to reduce the less significant parameter and give a preliminary judgment on the most significant water quality parameters discriminating the groundwater regions based on ANN model. This, study shows the use of sensitivity analysis combined with environmetric techniques such as Cluster Analysis (CA), Discriminant Analysis (DA). The water quality data was obtained from 10 different wells, over the period of 6 years (2006-2011) using 24 water quality parameters. Sensitivity analysis was carried out for nine models (ANN-R-AP, ANN-R-Na+, ANN-R-Ca+, ANN-R-HCO3, ANN-R-Cl-, ANN-R-SiO2, ANN-R-TDS, ANN-R-pH, ANN-R-EC). Percentage of contribution and R2 was used for model performance evaluation criterion. The CA allowed the formation of two clusters between the sampling wells. The Low Contaminant Level as LCL and moderate contaminant level as MCL reflecting differences on water quality at different locations. DA as a data reduction techniques was used to evaluate the spatial variability in water quality as it uses 6 parameters (SO4-,Cl-, As, Mn, NO2 and total dissolved solid) affording 90.00% correct assignation to discriminate between the clusters using forward stepwise mode from the original 24 parameters. The sensitivity analysis reveals that Na+, HCO3, SiO2 and EC are the four most effective parameters for discriminating groundwater quality regions with a percentage of contribution of 17.49, 17.50, 17.57 and 17.46%, respectively. This study reveals the significance of sensitivity analysis and multivariate techniques for the use of less parameter for understanding the most effective pollutant in water resource management, since, its time and cost consuming.
  Muhammad Barzani Gasim , Mohd Ekhwan Toriman and Hafizan Juahir
  The structural development of the late Palaeozoic metamorphic rocks in the study area has become weak since Cretaceous deformations due to presence of discontinuity planes. Because of long exposure, the climatic factors and weathering process have caused the crop out of these rocks and have experienced failure and movements. The aim of this study is to determine direction of slope failures of the rocks based on structural interpretation. The geology of study area is dominated by low-grade metamorphic rocks, consisting of interbedded phyllite, schist and quartzite. The dip direction and dip amount of the beddings and joints were measured during fieldwork, the result were plotted and interpreted on the Schmidt net in order to recognize and characterise their structural pattern. The weathered rock slope is characterised by high angle joints (74-80°) with dip directions between 330° and 20°. The rocks folded with northwest trending fold axes with dip direction and dip amount of the beddings are 235°/25°, 246°/23° and 250°/24° and other bedding planes are 351°/25°, 352°/24°, 354°/24°. The joint orientations are approximately perpendicular to the direction of the beddings. Some reverse faults (55°/15°, 60°/22°, 75°/35°, 85°/45° and 87°/28°) also cut across the bedding planes. Based on the discontinuity and landslide analyses, the failure occurred along the easterly dipping of the discontinuities, intersecting with variably oriented releasing joints that give rise to planar, toppling and wedge failures.
  Hazilia Hussain , Mohd Kamil Yusoff , Mohd Firuz Ramli , Puziah Abd Latif , Hafizan Juahir and Mohamed Azwan Mohammed Zawawi
  Nitrate-nitrogen leaching from agricultural areas is a major cause for groundwater pollution. Polluted groundwater with high levels of nitrate is hazardous and cause adverse health effects. Human consumption of water with elevated levels of NO3¯N has been linked to the infant disorder methemoglobinemia and also to non-Hodgkin’s disease lymphoma in adults. This research aims to study the temporal patterns and source apportionment of nitrate–nitrogen leaching in a paddy soil at Ladang Merdeka Ismail Mulong in Kelantan, Malaysia. The complex data matrix (128x16) of nitrate-nitrogen parameters was subjected to multivariate analysis mainly Principal Component Analysis (PCA) and Discriminant Analysis (DA). PCA extracted four principal components from this data set which explained 86.4% of the total variance. The most important contributors were soil physical properties confirmed using Alyuda Forecaster software (R2 = 0.98). Discriminant analysis was used to evaluate the temporal variation in soil nitrate-nitrogen on leaching process. Discriminant analysis gave four parameters (hydraulic head, evapotranspiration, rainfall and temperature) contributing more than 98% correct assignments in temporal analysis. DA allowed reduction in dimensionality of the large data set which defines the four operating parameters most efficient and economical to be monitored for temporal variations. This knowledge is important so as to protect the precious groundwater from contamination with nitrate.
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