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Development of an Optimal Reservoir Pumping Operation for Adaptation to Climate Change
Tarmizi Ismail,Sobri Harun,Zaitul Marlizawati Zainudin,Shamsuddin Shahid,Abu Bakar Fadzil,Usman Ullah Sheikh 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.1
Optimization of operation rule curve of Layang reservoir located in southern part of peninsular Malaysia under climate change uncertainties has been presented in this study. Downscaled climate data were incorporated in a lumped rainfall-runoff model to project daily reservoir inflow, which was then used to determine the reservoir operation rule curves to minimize the operation cost. The results reveal that climatic change will cause a rise of temperature in the range of 1.5-2.9oC, but decrease in rainfall in most of the months in the end of this century which will casue a change in the seasonal pattern of inflow to reservoir. Comparison of historical and model generated operation costs indicates that annual savings of 23% and 33% is possible with optimized reservoir operation rule curves. Assessment of the performance of the optimized operation curve under climate change scenarios shows that it will be able to cope with the changing pattern of reservoir inflow with proper adjustment. It is expected that the method presented in this paper to derive pumping operation curves to optimize the total volume of water to be pumped from various sources to reservoir can be useful for reservoir operators in the context of climate change.
Abdo Ali Homaid,Mohd Sobri Minai,Hamzah Abdul Rahman 세계문화관광학회 2015 International Journal of Culture and tourism Resea Vol.8 No.1
The main objective of the paper is to reveal empirically the effect of total quality management (TQM) practices on the Islamic Microfinance Institutions (MFIs) performance. Data was collected using a self-administered technique, distributed to 93 branch managers of the Islamic MFIs from June to August in 2014. A total of 71 usable questionnaires were obtained and smart PLS approach is used for data analysis. The findings showed that TQM has a significant effect on the performance of the Islamic MFIs. Out of seven practices being tested, only two practices were found to be positively significant contributors to the MFIs performance, which are training and quality culture. However, other practices of leadership management, customer focus, strategic planning, continuous improvement and benchmarking were not found to be the significant contributors. This is the contribution of this paper and the evidences should be of a great value to both academic and practitioners alike.
Afrasyab Khan,Mohd Sobri Takriff,Masli Irwan Rosli,Nur Tantiyani Ali Othman,Khairuddin Sanaullah,Andrew Ragai Henry Rigit,Ajmal Shah,Atta Ullah 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.1
Handling and utilization of steam flow efficiently to obtain various tangible industrial outcomes relies mainly upon how to optimize various flow parameters like boundary layer thickness, skewness, shear stress, and turbulent dissipation for minimum losses such as pressure and heat. Swirling steam flow, driven by a propeller through a circular duct along horizontal and inclined surfaces presents an interesting flow regime that includes the boundary layer flows close to the wall of the pipe and weak and uniform flow that prevails across the inner region of the pipe. Such flow was investigated here with a specially designed experimental facility. Convective Instabilities were observed that propagate along the axial direction in a nonlinear fashion. It was observed that the operating conditions could be optimized for measuring the shear stresses based on the intersection of the profiles under the effect of variations in the inlet pressure of steam and the rotational speed of the propeller. We found that the flow transformed from positive to negative skewness when the rotational speed of the propeller was raised from 4-14 thousand per minute at 10 bars of constant inlet steam pressure. More area came under the effect of reduced skin friction when the rotational speed of the propeller was raised. More turbulent energy was found to be dissipated when the rotational speed of the propeller was raised. It was found that yet the dissipation of the turbulent energy takes place under the joint effect of inlet pressure of steam and the rotational speed of the propeller, but the exact effect of any one of these two operating parameters still needs to be determined and requires further investigation.
Application of SVM and SWAT Models for Monthly Streamflow Prediction, a Case Study in South of Iran
Milad Jajarmizadeh,Elham Kakaei Lafdani,Sobri Harun,Azadeh Ahmadi 대한토목학회 2015 KSCE Journal of Civil Engineering Vol.19 No.1
The present study compares the results of the Soil and Water Assessment Tool (SWAT) with a Support Vector Machine (SVM) topredict the monthly streamflow of arid regions located in the southern part of Iran, namely the Roodan watershed. Data collected overa period of 19 years (1990-2008) was used to predict the monthly streamflow. Calibration (training) and validation (testing) wereperformed within the same period for both the models after the preparation of the required data. A semi auto-calibration was performedfor the SWAT model. Also, the best input combination of the SVM model was identified using the Gamma Test (GT). Finally, thereliability of the SWAT and SVM models were evaluated based on performance criteria such as the Nash-Sutcliffe (NS) modelefficiency coefficient and the Root Mean Square Error (RMSE). The obtained results from the development of the SWAT model andSVM model indicated satisfying performance in predicting the monthly streamflow in the large arid region. The SWAT obtained NSand RMSE values of 0.83 and 6.1 respectively, and the SVM obtained NS and RMSE values of 0.84 and 6.75 respectively for thevalidation (testing) period. Results indicate that for high flows of more than 19 (m3/s), both models predict flow with over and underestimation in the validation (testing) period. Moreover, the SVM has a closer value for the average flow in comparison to the SWATmodel; whereas the SWAT model outperformed for total runoff volume with a lower error in the validation period.
Xiaoju Li,Luqman Chuah Abdullah,Shafreeza Sobri,Mohamad Syazarudin Md Said,Siti Aslina Hussain,Tan Poh Aun,Jinzhao Hu 대한환경공학회 2024 Environmental Engineering Research Vol.29 No.4
The air pollution process and impact mechanism of megacities located in complex terrain are particularly complex. As a typical megacity in China, Chengdu has unique topographical and meteorological conditions, and its pollution control is difficult. This study systematically elucidated the variation characteristics of six criteria air pollutants in Chengdu between 2014 and 2020. Besides, the PM<SUB>2.5</SUB>/PM<SUB>10 </SUB>and NO₂/SO₂ ratios were discussed. Furthermore, a detailed analysis of the correlation between air pollutants was carried out. Finally, the collaborative path of carbon reduction and air pollution control is discussed. The results indicated that SO₂, PM<SUB>2.5</SUB>, PM<SUB>10</SUB> and CO were significantly decreased by 62.9%, 50.8%, 45.5%, and 36.7%, respectively. PM2.5 and O3 compliance rates are very low, and O₃ increases with fluctuations. SO₂, NO₂, CO, PM showed a “U-shaped” seasonal variation, and there was a “seesaw” phenomenon between O₃ and PM2.5. The continuous changing trends also found in the ratios of PM<SUB>2.5</SUB>/PM<SUB>10</SUB> and NO₂/SO₂. The results highlight the importance of coordinated reduction of carbon emissions and pollutants in Chengdu. This research can improve the prediction accuracy of air pollution in complex terrain areas under global warming, and improve the understanding of the formation mechanism of air pollution in special terrains around the world.
Hafed Qasem Ahmad,Samira A. Kamaruddin,Sobri B. Harun,Nadhir Al-Ansari,Shamsuddin Shahid,Ruqaya M. Jasim 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.11
The absence of a dense rainfall monitoring network and longer period data are the major hindrances of hydroclimatic study in arid and semi-arid regions. An attempt has been made for the evaluation of spatiotemporal changes in droughts at the northern semi-arid region of Iraq for the period 1981 − 2018 using high-resolution (0.05°) precipitation data of Climate Hazards Group Infrared Precipitation with Stations (CHIRPS). The performance of CHIRPS in replicating rainfall and Standard Precipitation Index (SPI) for different timescales at eleven locations for the available period of observation data (2000 − 2014) was evaluated. The SPI was also used to estimate drought frequency and evaluate drought trends at all the CHIRPS grid points. A modified version of the non-parametric Mann-Kendall (MK) test was employed for a robust evaluation of the spatial distribution of temporal trends in droughts. The results showed a good ability of CHIRPS in reconstructing observed SPI with a correlation coefficient ranged from 0.64 to 0.87, BIAS between 1.05 and 1.81, Nash-Sutcliff efficiency from 0.39 to 0.55, and Willmott Index between 0.67 and 0.79. The CHIRPS also able to reconstruct the time series and probability distribution of observed SPI reasonably. Spatial distribution of droughts revealed a higher frequency of droughts of all categories and timescales in the east and north of Northern Iraq, mainly due to high rainfall variance. The MK test revealed a reduction in 6- and 12-month droughts in the northwest and an intensification at a few northeastern grids. It indicates droughts became more recurrent in the already drought-prone region and lessened in a less drought-prone region.
Ahmed Y. Musa,Abu Bakar Mohamad,Abdul Amir H. Kadhum,Mohd Sobri Takriff,Waleed Ahmoda 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.1
Quantum chemical calculations were performed on ten thio compounds using semi-empirical method PM3 within program package of Material Studio 5.5. The effect of molecular structure on the corrosion inhibition efficiency was investigated using the quantum chemical calculations. The electronic properties such as highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) energy levels, (LUMO–HOMO) energy gap, dipole moment (l) and fraction of electron transfer (DN) were calculated and discussed. A relationship between the corrosion inhibition efficiency and several quantum parameters was established with coefficient correlation (R2) of 0.8894.