scholarly journals Specific aspects of the retrofitting design and seismic assessment of a heritage pedestrian bridge

2020 ◽  
Vol 63 (4) ◽  
pp. 65-77
Author(s):  
Emil Yanev
Keyword(s):  
Optimal Solution ◽  
Investment Project ◽  
Hydroelectric Power Plant ◽  
Normal Operation ◽  
Design Solution ◽  
Original Structure ◽  
Hydroelectric Power ◽  
Pedestrian Bridge ◽  
The Subject ◽  
Selection Of

The purpose of this study is to establish a suitable structural system for the restoration of the destroyed part of the pedestrian bridge, which is a part of a hydrocomplex built along the Arda River (Bulgaria), and to improve the vulnerable details in the original structure, taking into account the seismic hazard on the site. The decision is also dictated by the choice of a construction method that does not interfere the Hydroelectric Power Plant (HPP) that is built along the river with the normal operation of which the subject is connected. The appropriate selection of materials and modelling of the overall behaviour of the old and new parts of the bridge are the basis of the optimal solution for interference with the structure and the possibility of extending its service life. It is also important to preserve the visual unity of the whole structural complex, thus preserving the original appearance and good construction practice from the time they have been built during the middle of the 20th century This design solution is part of an investment project of "Risk Engineering" Ltd.

Multi-Objective Design and Selection of One Single Optimal Solution

2004 ◽  
Author(s):  
F. Levi ◽  
M. Gobbi ◽  
M. Farina ◽  
G. Mastinu
Keyword(s):  
Optimal Solution ◽  
Engineering Problem ◽  
Design Solution ◽  
Pareto Optimal ◽  
Large Set ◽  
Pareto Optimal Solutions ◽  
Optimal Solutions ◽  
Pareto Optimal Set ◽  
Final Design ◽  
Selection Of

In the paper, the problem of choosing a single final design solution among a large set of Pareto-optimal solutions is addressed. Two methods, the k-optimality approach and the more general k-ε-optimality method will be introduced. These two methods theoretically justify and mathematically define the designer’s tendency to choose solutions which are “in the middle” of the Pareto-optimal set. These two methods have been applied to the solution of a relatively simple engineering problem, i.e. the selection of the stiffness and damping of a passively suspended vehicle in order to get the best compromise between discomfort, road holding and working space. The final design solution, found by means of the k-ε-optimality approach seems consistent with the solution selected by skilled suspensions specialists. Finally the k-optimality method has proved to be very effective also when applied to complex engineering problems. The optimization of the tyre/suspension system of a sports car has been formulated as a design problem with 18 objective functions. A large set of Pareto-optimal solutions have been computed. Again, the k-optimality approach has proved to be a useful tool for the selection of a fully satisfactory final design solution.

Information Technologies and Mathematical Modeling in Solving Environmental Problems in the Design of Shore Protection Structures

2019 ◽  
Vol 23 (9) ◽  
pp. 13-17 ◽  
Author(s):  
T.Yu. Khashirova ◽  
Z.G. Lamerdonov ◽  
S.A. Zhaboev ◽  
M.A. Enaldieva ◽  
M.M. Thabisimova ◽  
...  
Keyword(s):  
Information Technologies ◽  
Optimal Solution ◽  
Environmental Indicators ◽  
Design Solution ◽  
Coastal Protection ◽  
Shore Protection ◽  
Innovative Solutions ◽  
The Russian Federation ◽  
Selection Of ◽  
Integral Indicator

The proposed methodology for the selection of the optimal design solution of the coastal protection structure, adapted to the specific hydrological, hydraulic and morphological conditions of the river according to an integral indicator, including the reliability of the structure; economic and environmental indicators. Innovative solutions to protect the banks of rivers from erosion, patented in the Russian Federation, decision-making modeling algorithms are presented. The developed theory and methodology for choosing the optimal solution can be implemented on other subsystems.

scholarly journals Design and selection of a belt drive for an electric generator

2021 ◽  
Vol 1199 (1) ◽  
pp. 012042
Author(s):  
M Dudziak ◽  
G Domek
Keyword(s):  
Power Plant ◽  
Hydroelectric Power Plant ◽  
Propulsion System ◽  
Medium Size ◽  
Belt Drive ◽  
Hydroelectric Power ◽  
Power Generators ◽  
Electric Generator ◽  
Electric Generators ◽  
Selection Of

Abstract The issue of the selection of mechanical drive for medium size power generators was raised in the work. The issue begins with the analysis of the propulsion system in the hydroelectric power plant, in which the turbines were selected for the amount of water flowing and for these turbines electric generators. An overview of the available drive solutions pointed to belt transmissions, which must meet the task of transferring torque from the turbine to the generator. The solution must be durable, which is why the authors conducted a deep analysis of material issues and pointed to modern polymer strips that can meet the challenges posed.

scholarly journals Repairing earth dam drainage systems

Vestnik MGSU ◽  
2019 ◽  
pp. 901-911
Author(s):  
Denis A. Krutov
Keyword(s):  
Reinforced Concrete ◽  
Drainage System ◽  
Hydroelectric Power Plant ◽  
Earth Dam ◽  
Design Solution ◽  
Filtration Flow ◽  
Hydroelectric Power ◽  
Drainage Channel ◽  
Open Drainage ◽  
Drainage Systems

Introduction: when reconstructing or overhauling dams, great attention should be paid to drainage systems as the most critical components of the installations. The article describes the typical malfunctions of earth dam pipe drainages. The research considers geological and hydrogeological features that were not taken into account when developing projects. Materials and methods: control and measuring instrumentation (piezometer network), full-scale experiments on disabling pipe drainage and mathematical modelling were used as the filtration regime research methods. Results: analysis of the hydrogeological features of the base of the right-bank floodplain dam of the Nizhegorodskaya hydroelectric power plant and field filtration observations revealed a strong drainage effect of the base on the filtration flow at several areas of the dam body. At the other areas, a high groundwater level position at the dam downstream and its outlet into the pipe drainage at the downstream were recorded. Substantiated by filtration calculations, the proposed repair of the drainage system consisted in designing open drainage along the dam axis and backfilling the territory at the downstream by 2.0 m that excludes impoundment of the territory without the pipe drainage. Conclusions: the following engineering solutions can be recommended for repairing earth dam drainage systems: construction of backfill drainage trenches in the dam downstream, new pipe drainage at higher elevations or an open drainage channel in solid reinforced concrete arranged along the axis of the dam. The proposed version of the pipe drainage repair provides for constructing an open drainage channel in solid reinforced concrete on a reverse filter with an arrangement of gravel-filled asbestos-cement pipes in the dam slopes and bottom. Such a design solution allows repairing the drainage system without dewatering and, if necessary, completely refusing the existing pipe drainage.

CFD Simulation of the Submerged Cofferdams Effect on the Operation of the Future Tocoma Hydroelectric Power Plant

2009 ◽  
Author(s):  
Milan Stanko ◽  
Andrea Shmueli ◽  
Miguel Asuaje ◽  
Frank Kenyery ◽  
Gonzalo Montilla ◽  
...  
Keyword(s):  
Power Plant ◽  
Velocity Profile ◽  
Cfd Simulation ◽  
Numerical Study ◽  
Computational Cost ◽  
Hydroelectric Power Plant ◽  
Normal Operation ◽  
Hydroelectric Power ◽  
Uniform Velocity ◽  
Operation Conditions

The Tocoma hydroelectric power plant, currently under construction, is located on the lower basin of the Caroni River in Bolivar State in Venezuela. This power plant will have 10 Kaplan turbines in its powerhouse that will generate approximately 2160 MW of hydroelectric power. During its construction, two cofferdams designated “A” and “B” will be built and afterwards will remain submerged. The main purpose of this experimental-numerical study is to analyze the possible future hydrodynamic effects of these structures on the operation of the Kaplan turbines. The presence of the submerged cofferdams could originate tridimensional hydrodynamic behaviors that could produce energy looses and operational and functional problems to the turbines. Two mathematical steady state single phase models using Computational Fluid Dynamics (CFD) Techniques and applying the commercial software ANSYS-CFX were developed. The first model represented the hydroelectric power plant reservoir that was quantitatively and qualitatively calibrated with a Froude Similarity 1:80 Scale Physical Model. Hydrodynamic flow patterns near to the intakes were found in the first model. Those patterns showed a non-uniform velocity profile in the unit’s intakes nearest to cofferdam “B”. The second mathematical model represented the study of the intake, the semi-spiral case and the Kaplan turbine. This model considers the non-uniform velocity profile that was found in the first model as an inlet boundary condition. Two methodologies were used to develop this model: one using two simulations with two overlapping physical domains, and the other one using the whole geometry. It was found that using overlapping domains in order to reduce the computational cost of the total simulation is a good way to obtain physical results with fair accuracy. The general results reported that the velocity profile at the intake of the powerhouse does not produce any stationary non uniform behavior on the velocity and pressure profiles in the unit compared to the uniform velocity profile case. This result could be an indicator that the non uniform condition at the intake of the Kaplan Turbines at Tocoma will not affect the normal operation conditions of the unit.

Nonlinear Truss-Based Quasi-Static Structural Model for Force Distribution Predictions on Debris Containment Grids

2018 ◽  
Author(s):  
Jose Rodolfo Chreim ◽  
Joao Lucas Dozzi Dantas ◽  
Alessandro Alberto de Lima
Keyword(s):  
Power Plant ◽  
Structural Model ◽  
Free Stream ◽  
Hydroelectric Power Plant ◽  
Nonlinear Finite Element ◽  
Normal Operation ◽  
Natural Phenomenon ◽  
Hydroelectric Power ◽  
Nonlinear Finite Element Method ◽  
Madeira River

At the Madeira River, north of Brazil, a natural phenomenon threatens the integrity and normal operation of an on-site hydroelectric power plant; thus, assemblies of containment structures, called logbooms, are installed across the river in order to protect the power plant installations. A truss-based nonlinear finite element method numerical tool is developed with the objective of designing and analyzing these assemblies. Initially, only the influence of the upstream velocity field is considered, and future modifications to account for the debris are expected. Code and solution verifications show that the tool converges reasonably well; the numerical error is about 0.2% of the theoretical value, and the uncertainty is about the same order: the results agree with analytical solutions from the simple catenary model. Finally, the method is validated by comparing numerical and experimental data; a satisfactory agreement is obtained, ascertaining the accuracy of the method: differences between experimental and numerical results are no higher than 6% and the trend of the tension force as a function of the free stream is followed by the numerical method.

Identifying Measurement Invariant Item Sets in Cross-Cultural Settings Using an Automated Item Selection Procedure

Methodology ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 177-188 ◽  
Author(s):  
Martin Schultze ◽  
Michael Eid
Keyword(s):  
Measurement Invariance ◽  
Optimal Solution ◽  
Selection Procedure ◽  
Cross Cultural ◽  
Item Selection ◽  
Ant System ◽  
Item Quality ◽  
Ant System Algorithm ◽  
Selection For ◽  
Selection Of

Abstract. In the construction of scales intended for the use in cross-cultural studies, the selection of items needs to be guided not only by traditional criteria of item quality, but has to take information about the measurement invariance of the scale into account. We present an approach to automated item selection which depicts the process as a combinatorial optimization problem and aims at finding a scale which fulfils predefined target criteria – such as measurement invariance across cultures. The search for an optimal solution is performed using an adaptation of the [Formula: see text] Ant System algorithm. The approach is illustrated using an application to item selection for a personality scale assuming measurement invariance across multiple countries.

Thomas More’s Correspondence in a Spanish Ambiance

Moreana ◽  
2002 ◽  
Vol 39 (Number 149) (1) ◽  
pp. 41-60 ◽  
Author(s):  
Eugenio M. Olivares Merino
Keyword(s):  
The Subject ◽  
Selection Of

The recent reprinting of Álvaro de Silva’s 1998 edition of a selection of More’s letters prompts the author to examine the subject of Spanish translations of More, and of de Silva’s general commentary on More’s correspondence and on his relationship to other humanists. The author reflects on aspects of More’s personality as exposed in his letters and uses what he finds as a corrective to several biographical misconceptions. He points out the strengths and weaknesses of de Silva’s work and compares it with that of other translators, particularly Elizabeth Rogers, and notes the particularly Spanish quality of de Silva’s edition.

Water Level Control of Small-scale Hydroelectric Power Plant

2002 ◽  
Vol 122 (6) ◽  
pp. 989-994
Author(s):  
Shinichiro Endo ◽  
Masami Konishi ◽  
Hirosuke Imabayashi ◽  
Hayami Sugiyama
Keyword(s):  
Power Plant ◽  
Water Level ◽  
Hydroelectric Power Plant ◽  
Small Scale ◽  
Hydroelectric Power ◽  
Level Control

Tanks in the Spa Town. The New Book about the Events of the Year 1968 in Czechoslovakia

2019 ◽  
Vol 14 (1-2) ◽  
pp. 278-282
Author(s):  
Kirill A. Popov
Keyword(s):  
Fiftieth Anniversary ◽  
Warsaw Pact ◽  
Scientific Event ◽  
The Social ◽  
Prague Spring ◽  
The Subject ◽  
Scientific Terms ◽  
Selection Of ◽  
Regional Perspective ◽  
The Way

This review is devoted to the monograph by Jan Nedvěd “We do not decline our heads. The events of the year 1968 in Karlovy Vary”. The Karlovy Vary municipal museum coincided its publishing with the fiftieth anniversary of the Prague spring which, considering the way of the presentation, turned the book not only to scientific event but also to the social one. The book describes sociopolitical trends in the region before the year 1968, the development of the reformist movement, the invasion and advance of the armies of the Warsaw Pact countries, and finally the decline of the reformist mood and the beginning of the normalization. Working on his writing, the author deeply studied the materials of the local archive and gathered the unique selection of the photographs depicting the passage of the soviet army through the spa town and the protest actions of its inhabitants. In the meantime, Nedvěd takes undue freedom with scientific terms, and his selection of historiography raises questions. The author bases his research on the Czech papers and scarcely uses the books of Russian origin. He also did not study the subject of the participating of the GDR’s army in the operation Danube, although these troops were concentrated on the borders of Karlovy Vary region as well. Because of this decision, there are no materials from German archives or historiography in the monograph. In general, the work lacks the width of studying its subject, but it definitively accomplishes the task of depicting the Prague spring from the regional perspective.

Sign in / Sign up

Export Citation Format

Share Document