一种水污染的综合控制模型   总被引：1，自引：1，他引：0  

扎黑尔  崔广柏 《湖泊科学》2002,14(2):125-133

本文将水质预测及水污染控制措施有机地结合,选取水环境容量和污染指数作为水污染控制的参数,这样,一给对流－扩散水质方程的求解除就是实现本研究目的的关键,本研究彩和的模型在现有的水质模型基础上有所改进,因为其采用四点隐格式对水质进行预测,推求可接给污染物的环境容量值有为保证水质而陷定的污染物浓度值,从而制定相应的水污染控制措施,为整体考虑各种污染物的情况,建议彩和河流的污染指数进而推求综合污染指数,总之,本研究为水质保护提供了科学的计算方法,该法对水污染及污水对河道水质的影响是实用有效的。  相似文献   

Macrophytes’ Performance in Floating Treatment Wetlands for the Remediation of Ciprofloxacin-Contaminated Water     

Syed Wajid Ali Shah  Mujaddad ur Rehman  Samina Anwar  Azam Hayat  Ghulam Shabir  Razia Tahseen  Moazur Rahman  Ejazul Islam  Samina Iqbal  Muhammad Afzal 《洁净——土壤、空气、水》2023,51(2):2100435

The presence of trace antibiotics in domestic and industrial effluents poses a risk of toxicity to fauna and flora. The application of floating treatment wetlands (FTWs) is a low-cost and sustainable approach to remediate wastewater. In this study, the performance of different macrophytes vegetated in FTWs for the remediation of ciprofloxacin (CIP)-contaminated water is investigated. Six macrophytes, Brachia mutica, Typha domingensis, Phragmites australis, Canna indica, Cyperus laevigatus, and Leptochloa fusca, are vegetated in FTWs for the removal of CIP (50 mg L⁻¹) from water. The FTWs show the potential to remove 30–43.58 mg L⁻¹ CIP from water in 28 days. They also reduce the chemical oxygen demand (118–138 mg L⁻¹) and biochemical oxygen demand (35–45 mg L⁻¹) of water. Among the macrophytes, C. indica removes maximum (43.58 mg L⁻¹) and T. domingensis minimum (30 mg L⁻¹) CIP. Canna indica and T. domingensis exhibit the maximum and minimum increase (30% and 12% of dry biomass) in growth, respectively. This study reveals that the FTWs vegetated with different plant species exhibit varying performances in removing CIP from water. This investigation is a step forward toward sustainable bioremediation of water contaminated with antibiotics.  相似文献   

Classification of rocks radionuclide data using machine learning techniques     

Abdul Razzaq Khan  Adil Aslam Mir  Sharjil Saeed  Muhammad Rafique  Khawaja M. Asim  Talat Iqbal  Abdul Jabbar  Saeed Ur Rahman 《Acta Geophysica》2018,66(5):1073-1079

The aim of this study is to assess the performance of linear discriminate analysis, support vector machines (SVMs) with linear and radial basis, classification and regression trees and random forest (RF) in the classification of radionuclide data obtained from three different types of rocks. Radionuclide data were obtained for metamorphic, sedimentary and igneous rocks using gamma spectroscopic method. A P-type high-purity germanium detector was used for the radiometric study. For analysis purpose, we have determined activity concentrations of ²³²Th, ²²⁶Ra and ⁴⁰K radionuclides, published elsewhere (Rafique et al. in Russ Geol Geophys 55:1073–1082, 2014), in different rock samples and built the classification model after pre-processing the data using three times tenfold cross-validation. Using this model, we have classified the new samples into known categories of sedimentary, igneous and metamorphic. The statistics depicts that RF and SVM with radial kernel outperform as compared to other classification methods in terms of error rate, area under the curve and with respect to other performance measures.  相似文献   

Seismic activity prediction using computational intelligence techniques in northern Pakistan     

Khawaja M. Asim  Muhammad Awais  F. Martínez–Álvarez  Talat Iqbal 《Acta Geophysica》2017,65(5):919-930

Earthquake prediction study is carried out for the region of northern Pakistan. The prediction methodology includes interdisciplinary interaction of seismology and computational intelligence. Eight seismic parameters are computed based upon the past earthquakes. Predictive ability of these eight seismic parameters is evaluated in terms of information gain, which leads to the selection of six parameters to be used in prediction. Multiple computationally intelligent models have been developed for earthquake prediction using selected seismic parameters. These models include feed-forward neural network, recurrent neural network, random forest, multi layer perceptron, radial basis neural network, and support vector machine. The performance of every prediction model is evaluated and McNemar’s statistical test is applied to observe the statistical significance of computational methodologies. Feed-forward neural network shows statistically significant predictions along with accuracy of 75% and positive predictive value of 78% in context of northern Pakistan.  相似文献   

Farmers’ perceptions of and adaptations to drought in Herat Province,Afghanistan     

Mohammad Wasim Iqbal  Somchai Donjadee  Bancha Kwanyuen  Shi-yin Liu 《山地科学学报》2018,15(8):1741-1756

Drought is a significant natural hazard in Herat Province, Afghanistan. The objective of this study was to explore farmers’ perceptions of the drought’s prevalence and characteristics, its socioeconomic and environmental impacts, their strategies for coping with and mitigating it, and types of conflicts and resolution mechanisms. A questionnaire was completed by 147 farming households. The results indicate that farmers' perceptions regarding drought are in line with the results obtained using the precipitation data. Even though the respondents have religious belief in interpreting the weather related issues, they also perceived drought as the climatic and environmental factors such as increased temperature, decreased precipitation, and other factors like war, financial weakness, deforestation, over-exploitation of groundwater, lack of electricity supply etc. The results show that drought has had serious economic impacts, including loss of employment and reduction in crop yield and livestock production, which have reduced farmers’ livelihood options and weakened their financial situation. Social impacts have included migration, a sense of hopelessness and loss, conflicts over water, health problems, impacts on the schooling of children, malnutrition, and limits to food options. Significant environmental impacts such as an increase in temperature, pasture and forest degradation, deterioration of water quality, damage to fish and wildlife habitats, and groundwater depletion were also reported. Farmers used local techniques to adapt to drought and lessen its effects. Farmers perceived irrigation water to be a major source of conflict. Local elders, water-user associations, and formal courts were reported to be the most successful conflict resolution methods. It is expected that the results of this study will support policy makers within government and development agencies in Afghanistan to develop future drought adaptation policies.  相似文献   

Periodic orbits generated by Lagrangian solutions of the restricted three body problem when one of the primaries is an oblate body     

Amit Mittal  Iqbal Ahmad  K. B. Bhatnagar 《Astrophysics and Space Science》2009,319(1):63-73

We have studied periodic orbits generated by Lagrangian solutions of the restricted three body problem when one of the primaries is an oblate body. We have determined the periodic orbits for different values of μ, h and A (h is energy constant, μ is mass ratio of the two primaries and A is an oblateness factor). These orbits have been determined by giving displacements along the tangent and normal to the mobile coordinates as defined by Karimov and Sokolsky (Celest. Mech. 46:335, 1989). These orbits have been drawn by using the predictor-corrector method. We have also studied the effect of oblateness by taking some fixed values of μ, A and h. As starters for our method, we use some known periodic orbits in the classical restricted three body problem.  相似文献   

Enhanced MEMS-IMU/odometer/GPS integration using mixture particle filter   总被引：2，自引：2，他引：0  

Jacques Georgy  Tashfeen Karamat  Umar Iqbal  Aboelmagd Noureldin 《GPS Solutions》2011,15(3):239-252

Dead reckoning techniques such as inertial navigation and odometry are integrated with GPS to avoid interruption of navigation solutions due to lack of visible satellites. A common method to achieve a low-cost navigation solution for land vehicles is to use a MEMS-based inertial measurement unit (IMU) for integration with GPS. This integration is traditionally accomplished by means of a Kalman filter (KF). Due to the significant inherent errors of MEMS inertial sensors and their time-varying changes, which are difficult to model, severe position error growth happens during GPS outages. The positional accuracy provided by the KF is limited by its linearized models. A Particle filter (PF), being a nonlinear technique, can accommodate for arbitrary inertial sensor characteristics and motion dynamics. An enhanced version of the PF, called Mixture PF, is employed in this paper. It samples from both the prior importance density and the observation likelihood, leading to an improved performance. Furthermore, in order to enhance the performance of MEMS-based IMU/GPS integration during GPS outages, the use of pitch and roll calculated from the longitudinal and transversal accelerometers together with the odometer data as a measurement update is proposed in this paper. These updates aid the IMU and limit the positional error growth caused by two horizontal gyroscopes, which are a major source of error during GPS outages. The performance of the proposed method is examined on road trajectories, and results are compared to the three different KF-based solutions. The proposed Mixture PF with velocity, pitch, and roll updates outperformed all the other solutions and exhibited an average improvement of approximately 64% over KF with the same updates, about 85% over KF with velocity updates only, and around 95% over KF without any updates during GPS outages.  相似文献   

Flood risk assessment of River Indus of Pakistan   总被引：1，自引：1，他引：0  

Bushra Khan  Muhammad Jawed Iqbal  M. Ayub Khan Yosufzai 《Arabian Journal of Geosciences》2011,4(1-2):115-122

Annual flood peak discharges is widely used in risk assessment. Major sources of flooding in Pakistan are River Jhelum, River Chenab, River Kabul, and upper and lower parts of River Indus. These rivers are major tributaries of the River Indus System which is one of the most important systems of the world and the greatest system of Pakistan. River Indus is the longest river of Pakistan containing seven gauge stations and several barrages, and it plays a vital role in the irrigation system and power generation for the country. This paper estimates the risk of flood in River Indus using historical data of maximum peak discharges. On the basis of our analysis, we find out which dam/barrage reservoir need to be updated in capacity, and whether there are more dams/barrages needed.  相似文献   

Spectral analysis of local climatic fluctuations   总被引：1，自引：1，他引：0  

Muhammad J. Iqbal  J. Quamar  M. A. K. Yousufzai 《Arabian Journal of Geosciences》2011,4(1-2):291-298

This paper employs spectral analysis to detect regular cyclical patterns or periodicities of local climate parameters of five major cities of Pakistan. Our calculations show that the temperature of all major climate stations may be affected by ENSO or QBO or Sunspot Cycles. As for the rainfall, what we find is that Pakistan summer monsoon exhibits a fairly similar bienniality with that of the Indian monsoon.  相似文献   

Comparison of rockfall susceptibility assessment at local and regional scale: a case study in the north of Beijing (China)     

Xueliang Wang  Luqing Zhang  Jixin Ding  Qingfeng Meng  Javed Iqbal  Lihui Li  Zhifa Yang 《Environmental Earth Sciences》2014,72(11):4639-4652

This study shows a rockfall susceptibility assessment at local scale in north Beijing of China, including the identification of rockfall sources onsite by terrain and rock discontinuities analysis and run-out distance prediction by Rocfall^? simulation. Two types of rockfall were defined including one type on the cliffs with long inclined slopes and another type on the road slopes with low height. Two historical rockfall events were used to back-calibrating the parameters used for run-out distance simulation. Based on the work, rockfall susceptibility map at local scale was created in GIS, which was compared with the map obtained at regional scale (entire Huairou district scale). Due to the difference of approaches applied, procedure of assessment and types of source data acquired, the two resulting rockfall susceptibility maps are proved to be different. Still, both of them are useful and could be used at different level’s decision for rockfall prevention and mitigation. Different types of uncertainties exist in the study of rockfall susceptibility assessment. To reduce the uncertainties, studies on both approaches and techniques are suggested.  相似文献