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Occurrence of Fluoride in the Groundwater of Kaltungo Area and Environs, North Eastern Nigeria

Journal of Geoscience and Environment Protection 2019年第8期7卷 167-179页

作者： Shehu Mukkafa Jackson Makpane Ishaku Ibrahim Abdulkarim Kwami ahmed buba seli Usman Adamu Abubakar Abdulwahab Mohammed Bello Usman Abubakar Musa Usman Bappa Department of Environmental Management and Toxicology Federal University Dutse Dutse Nigeria Department of Geology School of Physical Science Modibbo Adama University of Technology Yola Nigeria Geology Department Gombe State University Gombe Nigeria Departmentof Civil Engineering Adamawa State Polytechnic Yola Nigeria Departmentof Chemistry Gombe State University Gombe Nigeria

The aim of the study is to assess the occurrence of fluoride in the groundwater of Kaltungo area and environs. Consumption of high fluoride waters clearly manifests in the majority inhabitant of the area in form of dental fluorosis especially in the majority of the populace. Thirty groundwater samples were collected from hand-dug wells and boreholes using standard method and were analyzed to determine the fluoride level. The results revealed that the Fluoride in the waters ranges from 0.8 to 1.94 mg/l with a mean value of 1.65 mg/l. No clear variations in fluoride content have been observed in both the borehole samples and those from the hand-dug wells. Ca-Mg-HCO3 and Ca-Mg-Cl are the two major water types obtained in the area, which have a good association with fluoride. Negative correlation is observed between fluoride and temperature, fluoride and magnesium, fluoride and potassium and poor correlation is observed between fluoride and chloride, fluoride and nitrate, fluoride and phosphates which rules out the possibility of anthropogenic source of the fluoride in the waters. Positive correlation between fluoride and iron, indicates that the presence of fluoride in the water is as a result of dissolution of biotite within the host rock (Basalt).

关键词： Anthropogenic Correlation Fluoride Kaltungo

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Differential Evolution for Urban Transit Routing Problem

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Journal of Computer and Communications 2016年第14期4卷 11-25页

作者： ahmed Tarajo buba Lai Soon Lee Department of Mathematics Faculty of Science Universiti Putra Malaysia Selangor Malaysia Laboratory of Computational Statistics and Operations Research Institute for Mathematical Research Universiti Putra Malaysia Selangor Malaysia

The urban transit routing problem (UTRP) involves the construction of route sets on existing road networks to cater for the transit demand efficiently. This is an NP-hard problem, where the generation of candidate route sets can lead to a number of potential routes being discarded on the grounds of infeasibility. This paper presents a new repair mechanism to complement the existing terminal repair and the make-small-change operators in dealing with the infeasibility of the candidate route set. When solving the UTRP, the general aim is to determine a set of transit route networks that achieves a minimum total cost for both the passenger and the operator. With this in mind, we propose a differential evolution (DE) algorithm for solving the UTRP with a specific objective of minimizing the average travel time of all served passengers. Computational experiments are performed on the basis of benchmark Mandl’s Swiss network. Computational results from the proposed repair mechanism are comparable with the existing repair mechanisms. Furthermore, the combined repair mechanisms of all three operators produced very promising results. In addition, the proposed DE algorithm outperformed most of the published results in the literature.

关键词： Urban Transit Routing Network Repair Mechanism Differential Evolution

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