Applications of genetic algorithms in groundwater quality management

Ph.D.Mustafa M. Ara

Global Sea Surface Temperature and Sea Level Rise Estimation with Optimal Historical Time Lag Data

Prediction of global temperatures and sea level rise (SLR) is important for sustainable development planning of coastal regions of the world and the health and safety of communities living in these regions. In this study, climate change effects on sea level rise is investigated using a dynamic system model (DSM) with time lag on historical input data. A time-invariant (TI-DSM) and time-variant dynamic system model (TV-DSM) with time lag is developed to predict global temperatures and SLR in the 21st century. The proposed model is an extension of the DSM developed by the authors. The proposed model includes the effect of temperature and sea level states of several previous years on the current temperature and sea level over stationary and also moving scale time periods. The optimal time lag period used in the model is determined by minimizing a synthetic performance index comprised of the root mean square error and coefficient of determination which is a measure for the reliability of the predictions. Historical records of global temperature and sea level from 1880 to 2001 are used to calibrate the model. The optimal time lag is determined to be eight years, based on the performance measures. The calibrated model was then used to predict the global temperature and sea levels in the 21st century using a fixed time lag period and moving scale time lag periods. To evaluate the adverse effect of greenhouse gas emissions on SLR, the proposed model was also uncoupled to project the SLR based on global temperatures that are obtained from the Intergovernmental Panel on Climate Change (IPCC) emission scenarios. The projected SLR estimates for the 21st century are presented comparatively with the predictions made in previous studies

Genetic algorithm for constrained optimization models and its application in groundwater resources management

Genetic algorithms (GAs) have been shown to be an efficient tool for the solution of unconstrained optimization problems. In their standard form, GA formulations are "blind" to the constraints of an optimization model when the model involves these constraints. Thus, in GA applications alternative procedures are used to satisfy the constraints of the optimization model. In this study, the method that is utilized in the Complex Algorithm to solve constrained optimization problems is abstracted to develop a repairing procedure for GAs. The proposed procedure, which handles infeasible solutions that may be generated in a standard GA process, is embedded into the conventional GA to yield an improved GA process (IGA) for the solution of optimization problems with equality and inequality constrains. Two numerical examples are included to demonstrate the effectiveness and efficiency of the proposed method for the solution of constrained optimization applications. Finally the IGA is successfully used to develop an optimal groundwater management plan for the Savannah, Ga. region

A Survey of Rural Residents’ Perception and Response to Health Risks from Hot Weather in Ethnic Minority Areas in Southwest China

Ethnic minority areas in southwestern China are facing frequent high-temperature heatwaves. The health risk perceptions and responses of the local residents need to be investigated in order to formulate public policies to mitigate the impacts of climate change on health. In this study, a household survey was conducted in Pengshui Miao and Tujia Autonomous County of Chongqing from January to February 2019. A total of 624 local residents were sampled using the multi-stage sampling method. We used multivariate logistic regression models to explore the factors affecting risk perceptions and responses with regard to hot weather. The results showed that despite a relatively high level of risk perception, the study population had a very low level of willingness to see a doctor (24.4%), especially ethnic minority residents (17.5%). In particular, 80% of residents were aware of climate warming and 79% of residents were aware of the health risks of hot weather. Almost all survey participants reported a response to hot weather, with more than half of the participants stating that they would go somewhere cooler (58.5%) and drink more water (56.3%). Compared with the Han Chinese, ethnic minority participants had a higher perception of warm temperature (p <0.001) and associated health risks (p <0.001) but a lower perception of physical discomfort (p <0.001) and aggravated diseases (p = 0.001). The logistic models indicated that ethnic minority, residence time, outdoor working hours, and health status can significantly influence perceptions and subsequently significantly affect coping behaviors. In conclusion, our findings provide significant implications for the development of policies and health education and promotion programs for ethnic minorities in southwest China to aid them in maintaining good health during future hot weather events

A computational method for wave propagation simulation in open channel networks

Issued as final reportCenter for Disease ControlNational Institute for Occupational Safety and HealthUnited States Department of Health and Human Service

Facile fabrication of magnetically recyclable Fe3O4/BiVO4/CuS heterojunction photocatalyst for boosting simultaneous Cr(VI) reduction and methylene blue degradation under visible light

It is a challenging problem that develops a low-cost, efficient and sustainable technology in order to remove heavy metals and organic contaminants in the practical wastewater. Herein, a novel recyclable Fe3O4/BiVO4/CuS (FBCu) heterojunction photocatalyst was facilely fabricated by a method, coating CuS nanoparticles on the surface of Fe3O4 and BiVO4 simultaneously. FBCu composite not only has the ability to degrade Cr(VI) or methylene blue (MB) alone under visible light irradiation, but also exhibits higher photocatalytic ability in simultaneously removing Cr(VI) and MB mixed pollutants. The superior photocatalytic performance of FBCu is related to the formation of p-n heterojunction, which extends the spectral response and facilitates the efficiency of charge carriers separation and utilization. Moreover, FBCu exhibits satisfactory properties of reusability and stability after five cycling experiments in the Cr(VI)-MB coexistence system. Furthermore, the detailed mechanism for simultaneous removal of mixed pollutants was proposed and verified by DRS results, photoelectrochemical analysis, scavenger experiments and electron spin resonance determination. This work provides a recyclable photocatalyst with eco-friendliness and multifunctional applications in water pollution. (C) 2021 Elsevier B.V. All rights reserved