The purpose of this study is to examine the use of hydraulic microturbines to make the most of the hydraulic energy available in pressurized water distribution systems. The study was carried out on suitable points of pressurized hydraulic networks, which are managed by Giahsa, a public enterprise responsible for the management of the municipal communities of services (MAS) in the province of Huelva, southwestern Spain. The distribution system situated between the Cabeza del Pasto reservoir in the Andévalo area (Huelva, Spain) and the wastewater treatment plant (WWTP) in the municipality of Puebla de Guzmán (Huelva, Spain) was examined. To obtain the exact amount of energy which reaches the microturbine, the energy conservation equation considering the loss of energy from friction was used. The results show different locations where it is possible to carry out the installation of a Francis turbine, which can generate an annual energy of approximately 280 MWh per year at the selected point, with an approximate investment cost of €20,000 per year, which means a recovery period of this investment of 2 years.

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Authors propose a beneficial methodology for hydrological planning in their study. Prospective evaluations of the basins’ net capacity can be done using the technique presented. The HEC-HMS (Hydrologic Modelling System) software can be used to estimate in a basin, the sediment emitted. For a certain precipitation, this methodology allows estimating, within a certain range, the gradual blockage of a reservoir, and even a projected date for total blockage. This has some applications to adopt corrective measures that prevent or delay the planned blockage deadlines. The model is of the semi-distributed type, estimating the generation and emission of sediments by sub-basins. The integration of different return periods in HEC-HMS with a semi-distributed model by sub-basins and the application of a mathematical model are the differentiating element of this research. The novelty of this work is to allow prognosing the reservoir sedimentation rate of basins in a local and regional scale with a medium and large temporary framework. The developed methodology allows public institutions to take decisions concerning hydrological planning. It has been applied to the case of “Charco Redondo” reservoir, in Cádiz, Andalusia, in southern Spain. Applying the methodology to this case, an average soil degradation of the reservoir basin has been estimated. Therefore, it is verified that in 50 years the reservoir is expected to lose 8.4% of its capacity.

This paper explains the mathematical foundations of a method for modelling semi-rigid unions. The unions are modelled using rotational rather than linear springs. A nonlinear second-order analysis is required, which includes both the effects of the flexibility of the connections as well as the geometrical nonlinearity of the elements. The first task in the implementation of a 2D Beam element with semi-rigid unions in a nonlinear finite element method (FEM) is to define the vector of internal forces and the tangent stiffness matrix. After defining the formula for this vector and matrix in the context of a semi-rigid steel frame, an iterative adjustment of the springs is proposed. This setting allows a moment–rotation relationship for some given load parameters, dimensions, and unions. Modelling semi-rigid connections is performed using Frye and Morris’ polynomial model. The polynomial model has been used for type-4 semi-rigid joints (end plates without column stiffeners), which are typically semi-rigid with moderate structural complexity and intermediate stiffness characteristics. For each step in a non-linear analysis required to adjust the matrix of tangent stiffness, an additional adjustment of the springs with their own iterative process subsumed in the overall process is required. Loops are used in the proposed computational technique. Other types of connections, dimensions, and other parameters can be used with this method. Several examples are shown in a correlated analysis to demonstrate the efficacy of the design process for semi-rigid joints, and this is the work’s application content. It is demonstrated that using the mathematical method presented in this paper, semi-rigid connections may be implemented in the designs while the stiffness of the connection is verified.

This study presents the application of the finite element method integrated with Terzaghi’s principle. The definition of a model in oedometric or confinement conditions for settlement estimation of a building after the construction of a tunnel, including the effect of Terzaghi’s principle, is an unresolved problem. The objectives of this work include the demonstration of the need for a minimum of three methodological states to estimate said settlement. For this, a specific methodology is applied to a case study, with eight load steps and four types of coarse-grained soils. In the studied case, two layers of 50 m and 5 m with different degrees of saturation are overlaying an assumed impermeable rock layer. The excavation of a tunnel of 15 m in diameter at a depth of 30 m with drainage lining inside the tunnel is assumed. The minimum distance from the tunnel’s outline to the mat foundation is 15.8 m. It is determined that the settlement, according to Terzaghi’s principle, is around 11% of the total settlement for the most compacted soil types, reaching 35% for the loose soil type, from the tunnel’s outline. In the mat foundation, it implies an increase in the differential settlement of up to 12%. It shows a nonlinear relationship between some of the variables in the analysis. To detect the collapse due to uplifting the tunnel invert, it was determined that it was not appropriate to model in oedometric conditions. The novelty of the investigation relies on identifying and determining the need for a minimum of three states for methodological purposes for a proper quantification of the total settlement: (i) before the construction of the tunnel, (ii) immediately after the excavation of the tunnel, but without groundwater inflow into the tunnel, and (iii) after the tunnelling, with stabilised groundwater inflow into the tunnel.

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The removal of water from mines was one of the key issues that former miners had to deal with. Roman colonists brought new technology to the Iberian Peninsula that addressed this problem. However, they did not invent this technology because it had already been applied to the growth of other endeavours in the Hellenistic society throughout the Eastern Mediterranean. In the mine, the Archimedes screw, waterwheels, bucket pulleys, and Ctesibius pumps were the primary drainage systems. In this essay, the primary characteristics, and modes of operation of machines are examined. Without leaving out the most significant finds made in the southwest of the Iberian Peninsula, one of the regions with the longest history of mining exploitation. To serve as a foundation for future research in this field, this work compares the primary mining mechanisms in ancient Huelva on a qualitative and quantitative level by the implementation of a TOPSIS methodology, a multi-criteria decision analysis method.

For this paper, a computer program was designed and developed to calculate which turbines could be placed in a water distribution system considering the hydraulic constraints. The aforementioned turbines are placed in locations where we have unused hydraulic energy, i.e., when this energy is dissipated by a regulating valve. In our case, what we do is place a turbine to make use of that excess energy. Once the data has been entered into the program, it provides the type or types of turbines that can be placed in each location, what power these turbines would be, and how much they would generate annually. The program offers us two calculation options. In the first, and simpler, one, it would be done using the net head at the location where the turbine is to be placed. For this option, it would only be necessary to introduce the flow rate, the net head, and the hours that the turbine will be in operation to perform the calculation. The second option would be in the case where we did not have the net head, and, instead, we had the gross head. In this case, we have to calculate the head losses. Normally, this would be the most used option because there are usually no pressure drops. To perform the calculation, in this case, it is necessary to know, apart from what is mentioned in the first option, the characteristics of the pipe (diameter, length, and material).