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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 26 (1990), S. 0 
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: : The economic feasibility of large-scale subsurface drainage projects in irrigated land is affected by construction costs. This study was conducted to evaluate the effect of two different types of subsurface drainage system layout on construction costs for a 1000 ha pilot area located in the Nile Delta of Egypt. The two types of layout studied were the conventional layout currently used in Egypt and the modified layout that was developed for reducing water losses from rice fields. When compared to the conventional layout, the modified layout resulted in a reduction of 6.74 percent in construction costs (714,464 US$ versus 766,142 US$). This cost reduction is explained by the need for lesser lengths of large diameter collector pipes with the modified layout, which results from the smaller drainage area of subsurface drainage systems (average 23.7 versus 30.8 ha). We have found that the cost of subsurface drainage can be minimized by reducing the area drained by each subsurface drainage system.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food processing and preservation 26 (2002), S. 0 
    ISSN: 1745-4549
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two neural network approaches — a moving-window and hybrid neural network — which combine neural network with polynomial regression models, were used for modeling F(t) and Qv(t) dynamic functions under constant retort temperature processing. The dynamic functions involved six variables: retort temperature (116–132C), thermal diffusivity (1.5–2.3 × 10−7m2/s), can radius (40–61 mm), can height (40–61 mm), and quality kinetic parameters z (15–39C) and D (150–250 min). A computer simulation designed for process calculations of food thermal processing systems was used to provide the fundamental data for training and generalization of ANN models. Training data and testing data were constructed by both second order central composite design and orthogonal array, respectively. The optimal configurations of ANN models were obtained by varying the number of hidden layers, number of neurons in hidden layer and learning runs, and a combination of learning rules and transfer function. Results demonstrated that both neural network models well described the F(t) and Qv(t) dynamic functions, but moving-window network had better modeling performance than the hybrid ANN models. By comparison of the configuration parameters, moving-window ANN models required more neurons in the hidden layer and more learning runs for training than the hybrid ANN models.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 34 (1998), S. 0 
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: : Two methods for analyzing uncertainty are described and compared in terms of their applicability for designing vegetated waterways. The first approach uses First and Second Order Analysis and the second employs Fuzzy Logic. The two methods were used to evaluate the uncertain parameters in the Manning formula, which is used for calculating the velocity of water flow in vegetated channels. Results indicate that both approaches can provide the designer with an indication of reliability of the estimates, a way of selecting a design option which meets a specified probability of success, as well as a means of comparing the relative importance of uncertainty in various input parameters. Also, the two methods have the common advantage of being simple and requiring less data about the uncertain parameters compared to the more comprehensive stochastic approaches. Although the Fuzzy Logic approach appears to provide a more conservative design because of its slightly higher variance, compared with the First and Second Order Analysis, both methods have proven to be reliable and suitable to deal with uncertainty.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 38 (2002), S. 0 
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: : This study explores the applicability of Artificial Neural Networks (ANNs) for predicting salt build-up in the crop root zone. ANN models were developed with salinity data from field lysimeters subirrigated with brackish water. Different ANN architectures were explored by varying the number of processing elements (PEs) (from 1 to 30) for replicate data from a 0.4 m water table, 0.8 m water table, and both 0.4 and 0.8 m water table lysimeters. Different ANN models were developed by using individual replicate treatment values as well as the mean value for each treatment. For replicate data, the models with twenty, seven, and six PEs were found to be the best for the water tables at 0.4 m, 0.8 m and both water tables combined, respectively. The correlation coefficients between observed salinity and ANN predicted salinity of the test data with these models were 0.89, 0.91, and 0.89, respectively. The performance of the ANNs developed using mean salinity values of the replicates was found to be similar to those with replicate data. Not only was there agreement between observed and ANN predicted salinity values, the results clearly indicated the potential use of ANN models for predicting salt build-up in soil profile at a specific site.
    Type of Medium: Electronic Resource
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