Abstract Artificial neural networks (ANNs) are capable of learning the relationships between the dependent and predictor surface water quality variables and have a high ability to predict from the new data set. In this study, two different ANN methods, the feedforward network (FFN) and the cascadeforward network (CFN) were applied to predict two surface water quality variables such as chlorophyll-a (Chl-a) and fecal coliform (FC) using twelve other variables as an input to the models. Both me...
Autori: Hasan Merdun, Ozer Cinar
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=25623

Abstract:The present paper presents an enhanced Activated Sludge Model No. 1 in which nitrification and denitrification are modelled astwo-step processes. The nitrification process is considered as a sequence of two steps carried out by two distinct genera ofbacteria, with nitrite as an intermediate product. For the denitrification process a parallel approach was used that considers nitrateand nitrite to be directly reduced to molecular nitrogen. The new model is compared to the original Activat...
Autori: George Simion Ostace, Paul Şerban Agachi, Vasile Mircea Cristea
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=25786

Abstract In a world of uncertainty, the only constant is change and rapid change produces a multitude of diverse facts. Risk is an integral part of life. While no country in the world is entirely safe, the lack of capacity to limit the impact of hazards remains a major burden for all countries and while the world has witnessed an exponential increase in human and material losses due to natural disasters, there is a need to reverse trends in vulnerability to earthquakes. Available d...
Autori: Gheorghe Mărmureanu
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=26140

The purpose of the reservoir operation during flood period is to obtain the outflow hydrograph as flat as possible. Although simple in case of a unique reservoir, the problem becomes very complex for large systems with cascade reservoirs. Based on the well-known hydraulic software Mike Flood by DHI, a simulation-optimization model containing wave propagation equations, constraints related to the state or decision variables as well as an objective function were developed for obtaining optimal coo...
Autori: Aurelian Florentin Draghia
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=27295

Cascade dams alter the movement and accumulation of heavy metals in sediments along the river continuum. 27 sample crosssections were taken in July 2011 from the Xiaowan, Manwan, and Dachaoshan dams in the middle reach of the Mekong River in southern China and analyzed for content of heavy metal (Zn, Cr, Pb, As, Cu, Ni, and Cd) concentrations in the dammed river reach. There were evident spatial variations of the heavy metal concentrations downstream and upstream of the three cascade dams; t...
Autori: Li Deng
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=27436

In the present research, four meta-heuristic algorithms named Genetic Algorithm (GA), Gravitational Search Algorithm (GSA), Particle Swarm Optimization (PSO), and Artificial Bee Colony (ABC) have been used for optimal design of cascade spillway to minimize the construction cost. Usually, the traditional design methods such as Vittal and Porey (VP) method or experimental modeling are used to solve this problem leading to infeasible or near optimal solution. The main novelty of this paper is to...
Autori: Pedram Jazayeri
ISSN: 1843 - 3707
http://www.ecozone.ro/reviste.php?RID=28195