Conference Presentations by othman jaafar
Nitrogen is seen as the most frequent threat to public health and the environment mainly due to t... more Nitrogen is seen as the most frequent threat to public health and the environment mainly due to the production of leachate which reduce the surface and groundwater quality. Groundwater samples were collected from well clusters and monitoring wells at the Taman Beringin landfill site from April to July 2014 to investigate nitrogen distributions and concentration levels in the site. The concentrations in the clustered wells in wet periods are: NH3-N (14.52), NO2 (0.13), NO3 (6.33) and the dry periods were: NH3-N (12.95) NO2 (0.1), NO3 (8.57) mg/L, respectively. The concentrations observed in monitoring wells in the wet periods are: NH3-N (56.06), NO2, (0.035), NO3 (2.4) and dry periods NH3-N (57.13), NO2, (0.03), NO3 (1.63) mg/L respectively. Of the Nitrogen species, the concentrations of NH3-N remained excessively higher relative to National Water Quality Standards (NWQS) for Malaysia. Variations observed in nitrogen chemistry are responses to well depth/types and aquifer properties.
Papers by othman jaafar
Wahana Teknik Sipil, 2010
Abstract Bangi Forest Reserve adjacent to Universiti Kebangsaan Malaysia (UKM) Bangi campus is a ... more Abstract Bangi Forest Reserve adjacent to Universiti Kebangsaan Malaysia (UKM) Bangi campus is a lowland secondary dipterocarp forest with a size of 100 hectares, which provides lush greenery freshness to UKM Bangi campus. Many constructions have been being developed within the UKM campus. During the construction time, it will create disturbance for the ecosystem on that area and cause a problem such as water pollution problem. In this paper the effect of constructions to surface flow water quality on Bangi ...
Jurnal Kejuruteraan, Nov 30, 2018
Road maintenance works performed by contractors require validation upon completion. Conventional ... more Road maintenance works performed by contractors require validation upon completion. Conventional methods are typically chosen to validate the works. Geographic Information System (GIS) is applied in this study to produce accurate data such that waste from road maintenance costs can be minimised. In this study, Unmanned Aerial Vehicle (UAV) was used to observe the images of two roads, namely Jalan Gelanggang and Jalan Temuan, both of which are under maintenance at the Universiti Kebangsaan Malaysia. The objectives of this study are; to determine the ability of UAV technology in supervision and verification of maintenance works, and the effectiveness of spatial works in road maintenance. This study then proceeds with analysing data by using ArcGIS and AutoCAD software to determine the width, perimeter, and area of the road that has been maintained. Comparisons were made between these two data which are the data that has been claimed and provided by the contractors (as-built data) and images data of the UAV whenever to get the percentage of the difference for several features of the road. Results from this study showed that the value for width, perimeter, and area of the as-built data for both roads are greater than the value of the image where the UAV data show percentage differences of shape area for Jalan Gelanggang is 3.27% and for perimeter is 1.35%. While percentage differences of shape area are for Jalan Temuan is 4.83% and for perimeter is 2.44%. Therefore, if UAV is used for work validation, the total saving on road maintenance work costs are saved at least RM6,386.28 for Jalan Gelanggang and RM5,775.24 for Jalan Temuan.
Iran oil industry has developed in current decades. The risks of this development always were con... more Iran oil industry has developed in current decades. The risks of this development always were considered by the decision-makers. Environmental risk is the process of qualitative analysis of hazard potentials and practical coefficients of the potential risks in the project and sensitivity or vulnerability of the surrounding environment. Hence, besides analyzing various aspects of risk by full knowledge of the local environment, sensitivity of the affected environment as well as the environmental values is applied in risk analysis. Tehran oil refinery was selected as a case study because this oil refinery is in construction and operation phase, so EIA plan can cover all phases of this plant. In Environmental Impact Assessment (EIA) of this study economical, environmental, land use and social parameters were considered in the EIA plan in two phases such as construction and operation of oil refinery during 2008-2012. By using Environmental Risk Assessment (ERA) and Geographic Information System (GIS) methods 512 maps were provided for EIA. Then the maps were overlaid on together final result of EIA maps in four parameters obtained based on the study plan for EIA of oil refineries in Iran. So the decision-making, assessing impacts and possible solutions will available for oil refineries in Iran.
IOP conference series, Dec 1, 2017
Unmanned Aerial Vehicles (UAV) technology has evolved dramatically in the 21 st century. It is us... more Unmanned Aerial Vehicles (UAV) technology has evolved dramatically in the 21 st century. It is used by both military and general public for recreational purposes and mapping work. Operating cost for UAV is much cheaper compared to that of normal aircraft and it does not require a large work space. The UAV systems have similar functions with the LIDAR and satellite images technologies. These systems require a huge cost, labour and time consumption to produce elevation and dimension data. Measurement of difficult objects such as water tank can also be done by using UAV. The purpose of this paper is to show the capability of UAV to compute the volume of water tank based on a different number of images and control points. The results were compared with the actual volume of the tank to validate the measurement. In this study, the image acquisition was done using Phantom 3 Professional, which is a low cost UAV. The analysis in this study is based on different volume computations using two and four control points with variety set of UAV images. The results show that more images will provide a better quality measurement. With 95 images and four GCP, the error percentage to the actual volume is about 5%. Four controls are enough to get good results but more images are needed, estimated about 115 until 220 images. All in all, it can be concluded that the low cost UAV has a potential to be used for volume of water and dimension measurement.
e-Bangi, Nov 27, 2017
ABSTRACT
Journal of Environmental Science and Technology, Oct 15, 2016
Objective: The purposes of this study was to determine the main parameters that affect the ecolog... more Objective: The purposes of this study was to determine the main parameters that affect the ecological conditions in marine water and to identify the similarity of the areas with respect to the water quality status. Materials and Methods: This is a quantitative study which focuses on multivariate statistics on time series data of six marine parameters from 12 monitoring stations in the Straits of Johor, Malaysia. Results: Principal component analysis revealed that there are three main factors involved in determining the distribution of parameters, namely physicochemical, chemical and organic contaminants with the variation proportions of 37, 20 and 18%, respectively. Cluster analysis showed that all stations can be categorized into 2 clusters with distinct characteristics in terms of water quality parameters. Conclusion: There are three main factors that characterize the marine waters. The clusters connect similar sampling stations in terms of parameters and pollution levels with comparable environmental activities. Three factors representing three different processes are related to the physicochemical pollution factor, the chemical pollution factor caused by decomposition of aquatic life and the organic contaminant factor. Both of the physical parameters (Temperature and conductivity) as well as the chemical parameter (TSS) were found to the most influential, in physicochemical pollution factor. The pH and Dissolve Oxygen (DO) are parameters in the chemical pollution factor. Oil and grease involved only in the organic contaminant factor. Stations, which are located at the border between Johor Bahru city and Singapore produce organic pollution and affect the DO level of aquatic life. Three monitoring stations located in different areas of the border are exposed to high values of TSS and pH. This shows that both the Western and Eastern parts of the Straits of Johor are highly exposed to chemical pollution. Weather conditions and timing changes are the constraints of this study.
Journal of Cleaner Production, 2019
In recent years, with the quick growth of the economy and living standards in Malaysia, keeping u... more In recent years, with the quick growth of the economy and living standards in Malaysia, keeping up with the water demand is essential for the growth of cultivation, domestic and industrial. With the merits of having dams and reservoirs, water releases from dams are usually used to respond to the water requirements of downstream dams. To match the practical water requirement considering spatial and temporal conditions, a novel optimization operation model has been formulated for minimizing the gap between the water release from a dam and the water requirement. In this context, there is a need to develop an optimization model to alleviate the complexity and multidimensionality of a dam and reservoir as water supplies and the water demand system. In this research, an optimization algorithm, namely, the shark machine learning algorithm (SMLA) that has high inertia for obtaining its targets, is proposed that mimics the natural shark process. The major objective for the proposed model is attaining the minimum difference between the water demand volume and water release. To examine the proposed model, SMLA has been utilized in determining the optimal operation policies for Timah Tasoh Dam, located in Malaysia. A new procedure to evaluate the performance of optimization models by integrating reservoir inflow forecasting with operational rules generated by optimization models has been proposed. Accordingly, two predictive models, namely, radial basis function neural network (RBF-NN) and support vector regression (SVR), have been developed to forecast monthly reservoir inflow. The test results revealed that the SVR forecasts monthly reservoir inflow better than the RBF-NN model. Additionally, the SMLA attained more reliable, resilient and less vulnerable results in the operation of the reservoir system compared to that of other optimization models. In addition, SMLA has demonstrated a significant change in the performance indicator values when using forecasted reservoir inflow data rather than deterministic reservoir inflow data.
Neural Computing and Applications, Dec 16, 2016
Stream-flow forecasting is a crucial task for hydrological science. Throughout the literature, tr... more Stream-flow forecasting is a crucial task for hydrological science. Throughout the literature, traditional and artificial intelligence models have been applied to this task. An attempt to explore and develop better expert models is an ongoing endeavor for this hydrological application. In addition, the accuracy of modeling, confidence and practicality of the model are the other significant problems that need to be considered. Accordingly, this study investigates modern non-tuned machine learning data-driven approach, namely extreme learning machine (ELM). This data-driven approach is containing single layer feedforward neural network that selects the input variables randomly and determine the output weights systematically. To demonstrate the reliability and the effectiveness, one-step-ahead stream-flow forecasting based on three time-scale pattern (daily, mean weekly and mean monthly) for Johor river, Malaysia, were implemented. Artificial neural network (ANN) model is used for comparison and evaluation. The results indicated ELM approach superior the ANN model level accuracies and time consuming in addition to precision forecasting in tropical zone. In measureable terms, the dominance of ELM model over ANN model was indicated in accordance with coefficient determination (R 2 ) root-mean-square error (RMSE) and mean absolute error (MAE). The results were obtained for example the daily time scale R 2 = 0.94 and 0.90, RMSE = 2.78 and 11.63, and MAE = 0.10 and 0.43, for ELM and ANN models respectively.
Theoretical and Applied Climatology, Oct 14, 2017
Existing forecast models applied for reservoir inflow forecasting encounter several drawbacks, du... more Existing forecast models applied for reservoir inflow forecasting encounter several drawbacks, due to the difficulty of the underlying mathematical procedures being to cope with and to mimic the naturalization and stochasticity of the inflow data patterns. In this study, appropriate adjustments to the conventional coactive neuro-fuzzy inference system (CANFIS) method are proposed to improve the mathematical procedure, thus enabling a better detection of the high nonlinearity patterns found in the reservoir inflow training data. This modification includes the updating of the back propagation algorithm, leading to a consequent update of the membership rules and the induction of the centre-weighted set rather than the global weighted set used in feature extraction. The modification also aids in constructing an integrated model that is able to not only detect the nonlinearity in the training data but also the wide range of features within the training data records used to simulate the forecasting model. To demonstrate the model's efficacy, the proposed CANFIS method has been applied to forecast monthly inflow data at Aswan High Dam (AHD), located in southern Egypt. Comparative analyses of the forecasting skill of the modified CANFIS and the conventional ANFIS model are carried out with statistical score indicators to assess the reliability of the developed method. The statistical metrics support the better performance of the developed CANFIS model, which significantly outperforms the ANFIS model to attain a low relative error value (23%), mean absolute error (1.4 BCM month -1 ), root mean square error (1.14 BCM month -1 ), and a relative large coefficient of determination (0.94). The present study ascertains the better utility of the modified CANFIS model in respect to the traditional ANFIS model applied in reservoir inflow forecasting for a semi-arid region.
Environment Protection Engineering
AINA IZZATI MUHAMMAD RASHID (ORCID 0000-0002-1068-566X) 1, 2 ROSIAH ROHANI (ORCID 0000-0002-4391-... more AINA IZZATI MUHAMMAD RASHID (ORCID 0000-0002-1068-566X) 1, 2 ROSIAH ROHANI (ORCID 0000-0002-4391-4043) 1, 3 OTHMAN JAAFAR (ORCID 0000-0002-0820-6260) 2 NUR SHAZWANI MUHAMMAD (ORCID 0000-0002-2432-4822) 2 Chlorine is a popular disinfectant used in Malaysia in the treatment process of drinking water supply because of its effectiveness. The concentration of chlorine deteriorates upon travelling in the system due to its reaction with organic matter to produce carcinogenic substances known as disinfection by-products (DBP) such as trihalomethanes (THM). This study was conducted to investigate chlorine decay and THM formation in a state's drinking water distribution system in Malaysia specifically across a 24.9 km distance. EPANET 2.0 Software program was used to perform hydraulics and water quality analysis using the extended period simulation (EPS) for 24 hours demand pattern. A simulation of the water distribution system was performed to identify the formation of THM and its relationship between chlorine and total organic carbon (TOC). The value of THM was maintained at a lower level at the water treatment plant (WTP) than at the endpoint of the distribution system. At the endpoint, which was at the targeted industrial area, the level of THM was found to increase and the obtained data showed that its formation occurred along the investigated distribution system. THM formation manifested as the natural organic matter (NOM) presence along the pipe continuously reacted with chlorine which was dosed in the distribution system.
Research Journal of Applied Sciences, Engineering and Technology, 2013
The increase in water age may be due to the distance travelled and the residence time in the wate... more The increase in water age may be due to the distance travelled and the residence time in the water distribution. The water age of the blind spots in water distribution system causes deterioration in water quality systems. In general, blind spots have been causing increased water age in the water distribution network. Water age has more value in distribution systems with Lang transmission lines. For blind spots (dead end point), there has been an analysis of the primary distribution system. The goal of this study is to improve the water age and water quality as well as minimizing incidences of dead end points in the water distribution systems with the use of EPANET model software. Considering the above results this study for minimizing incidences of dead end points in the water distribution systems will be water age, smaller water and removal of the blind spots are required and need for the design of a pipe diameter that would effectively accommodate blind spots by ensuring appropriate sizes at appropriate points along the system network, so Pressure must be maintained in the distribution network system. Finally, the amount water age and generation of blind spots in the system and distribution network will be due to inaccuracies in network design and distribution systems or inability to consider some important factors when designing the distribution network system.
Sains Malaysiana, 2017
Presently, climate change plays an important role as it gives a serious impact to the living thin... more Presently, climate change plays an important role as it gives a serious impact to the living things on earth. Analyzing the trend of climate change is very important in identifying the pattern of changes because it can give an initial overview for future analysis. In this study, trend analysis was carried out to study the pattern of changes for five climate change parameters, such as total amount of monthly precipitation (mm), monthly average temperature (°C), monthly average global radiation (MJm -2 ), monthly average wind speed (m/s) and monthly average humidity (%) during the period of 1974 to 2010. Comparisons were made between two research stations, which were the Senai International Airport and Kluang Meteorological Stations. In this study, the Mann-Kendall trend test and Sen's slope estimator test were used to identify the monotonic trend for these climate change parameters. As a result of this analysis, the precipitations showed no trend for both locations and the radiation showed no trend in Kluang from both analyses. Meanwhile, other parameters in Senai and Kluang showed a monotonic trend, according to the Tau value (Z) and the Sen's slope value. The temperature shows a positive trend for both locations.
Research Journal of Applied Sciences, Engineering and Technology, 2013
One of the parameter that could reason to decrease water quality in distribution system is veloci... more One of the parameter that could reason to decrease water quality in distribution system is velocity change in networks. This study is to analyze the effects velocity changes on the water quality in water distribution systems. We need to choose different locations that will be water quality and quantity relative too much. Location of the study has been in Ahwaz of Iran. There are two instances for the conduct of this analysis, local environment and Laboratory condition and this analysis had been done independently as far as the plants are concerned. The results showed that the distance travelled and residence time have been causing to increase bacterial growth (HPC), hydraulic change in water distribution system in Ahwaz so, velocity has a reversed relationship with bacterial growth (HPC). Velocity change has been causing to increase bacterial growth (HPC) so change Velocity has a direct relationship with residual chlorine. Velocity change has been causing to increase chlorine consumption more. Also, Kw hasn't any relationship with change velocity and bacterial growth (HPC) and change Velocity has a direct relationship with turbidity with the aid of the diagrams and Figures, the results of station sampling in the water distribution systems of Ahwaz have shown that the systems have large transmission line and have extensive networks.
Research Journal of …, 2011
Odor pollution from the landfill is one component of pollutants that affect the human environment... more Odor pollution from the landfill is one component of pollutants that affect the human environment. Issues and odor complaints from the landfill had been made through the media, official complaints and protests of the people living near the landfills. This study attempts to get the feedback from the people living near the landfill. It was conducted within 2 km radius of the landfill. Part of the study involves a perception survey to determine the influence of odors on the social, health, welfare and discomfort level. The study also determined the levels, duration and intensities of the unpleasant odors. The results showed that the strong smell is normally experienced following rainfall events. Meteorological factors such as wind speed and wind direction were also considered to assess the acceptance of the local community towards the smell nuisance. The findings also showed that the smell from the landfill has caused daily discomfort as result of intermittent or continuous malodorous from the community feedback.
Nucleation and Atmospheric Aerosols, 2018
Rainfall especially in tropical region caused infiltration to the soil slope. The infiltration ma... more Rainfall especially in tropical region caused infiltration to the soil slope. The infiltration may change pore water pressure or matric suction of the soil. The event of rainfall infiltration into soil is a complex mechanism. Therefore, the main objectives of this research paper is to study the influence of rainfall intensity and duration that changed pore water pressure to soil. There are two types of soils used in this study; forest soil and kaolin. Soil column apparatus is used for experiments. Rainfall were applied to the soil and result for 3, 6, 12, 24, 72, 120 and 168 hours were retrieved. Result shows that for the both types of soil, the negative pore water pressures were increased during wetting process and gradually decreased towards drying process. The results also show that pore water pressure at top part was increased greatly as the wetting process started compared to the middle and bottom part of the column.
Journal of Hydrology, 2016
Abstract Monthly stream-flow forecasting can yield important information for hydrological applica... more Abstract Monthly stream-flow forecasting can yield important information for hydrological applications including sustainable design of rural and urban water management systems, optimization of water resource allocations, water use, pricing and water quality assessment, and agriculture and irrigation operations. The motivation for exploring and developing expert predictive models is an ongoing endeavor for hydrological applications. In this study, the potential of a relatively new data-driven method, namely the extreme learning machine (ELM) method, was explored for forecasting monthly stream-flow discharge rates in the Tigris River, Iraq. The ELM algorithm is a single-layer feedforward neural network (SLFNs) which randomly selects the input weights, hidden layer biases and analytically determines the output weights of the SLFNs. Based on the partial autocorrelation functions of historical stream-flow data, a set of five input combinations with lagged stream-flow values are employed to establish the best forecasting model. A comparative investigation is conducted to evaluate the performance of the ELM compared to other data-driven models: support vector regression (SVR) and generalized regression neural network (GRNN). The forecasting metrics defined as the correlation coefficient ( r ), Nash-Sutcliffe efficiency ( E NS ), Willmott’s Index ( WI ), root-mean-square error ( RMSE ) and mean absolute error ( MAE ) computed between the observed and forecasted stream-flow data are employed to assess the ELM model’s effectiveness. The results revealed that the ELM model outperformed the SVR and the GRNN models across a number of statistical measures. In quantitative terms, superiority of ELM over SVR and GRNN models was exhibited by E NS = 0.578, 0.378 and 0.144, r = 0.799, 0.761 and 0.468 and WI = 0.853, 0.802 and 0.689, respectively and the ELM model attained lower RMSE value by approximately 21.3% (relative to SVR) and by approximately 44.7% (relative to GRNN). Based on the findings of this study, several recommendations were suggested for further exploration of the ELM model in hydrological forecasting problems.
American Journal of Environmental Sciences, 2015
Effective and rational management of groundwater resources require adequate information on the gr... more Effective and rational management of groundwater resources require adequate information on the groundwater flow interactions with surface water and chemical species in the flow regime. The hydrologic conditions beneath the unlined ex-landfill site in Jinjang Kuala Lumpur were investigated to understand the groundwater flow and geochemical setting in which contaminants transport in the groundwater may occur in the ex-landfill. The MODFLOW 2000 was used to construct the groundwater flow regime. The model was set up and calibrated as a three (3) layer steady-state MODFLOW model. The MODFLOW model revealed that the hydraulic gradient of the groundwater flow in the landfill site is to the northeast , towards Jinjang River which is located on the eastern part of the landfill. There is also groundwater movement towards the southeast of the landfill towards the Nanyang and Wahyu Ponds. It was concluded that quick action is deemed necessary to protect Jinjang River and Nanyang Pond which are hydraulically connected with the same aquifer and the geochemical setting in which contaminants transport may occur in the ex-landfill is in the same direction as the flow of the two water bodies. Recommendations are suggested to reduce the groundwater level by pumping below the height of the river bed, so that there is no contamination to the river and pond via recharge of groundwater into the river, instead the river should recharge to the groundwater.
International Journal of Physical Sciences, Dec 16, 2011
In fact, the reservoir simulation is an essential step while developing the optimal operation pol... more In fact, the reservoir simulation is an essential step while developing the optimal operation policy for dam and reservoir. Generally, an accurate simulation for the reservoir characteristics should lead more reliable and robust optimization model for certain reservoir. The major challenge in the reservoir simulation is the non-linearity behavior of interrelationships between the reservoir elevation, surface area and storage. The existing traditional modeling methods usually solve such problem in linear fashion, thus, it achieves relatively poor accurate simulation especially at extreme values, which affect the reliability of the optimization model. The use of artificial neural networks (ANNs) is becoming increasingly common in the analysis of hydrology and water resources problems and it may replace the classical regression model hitherto used most especially for non-linear system. Two different types of ANN namely, feed-forward back-propagation neural network (FBNN) and radial basis function neural network (RBFNN) were used in this study to simulate the interrelationships between elevation, surface area and storage capacity at Langat reservoir system, Malaysia. In addition, classical auto regression (AR) model was developed for comparative analysis over the proposed ANN model. The main finding of this study showed that proposed ANN model could significantly improve the simulation accuracy over the classical AR mode. On the other hand, the results obtained for RBFNN were found to be more accurate than the simulation of AR and FBNN. This study thus concludes that the ANN method is more suitable to simulate the reservoir behavior than the classical regression model.
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Conference Presentations by othman jaafar
Papers by othman jaafar