- Détails du magazine
- Format
- Magazine
- eISSN
- 1338-3973
- ISSN
- 1210-3896
- Première publication
- 23 May 2011
- Période de publication
- 4 fois par an
- Langues
- Anglais

#### Chercher

- Accès libre

Evaluation of the Hydropower Generation Potential of a Dam Using Optimization Techniques: Application to Doma Dam, Nassarawa, in North Central Nigeria

Pages: 1 - 9

#### Résumé

Optimization models have been developed to maximize annual energy generation from the Doma dam, subject to the constraint of releases for irrigation, ecological purposes, the water supply, the maximum yield from the reservoir and reservoir storage. The model was solved with LINGO software for various mean annual inflow exceedence probabilities. Two scenarios of hydropower retrofitting were considered. Scenario 1, with the reservoir inflows at 50%, 75%, and 90% probabilities of exceedence, gives the total annual hydropower as 0.531 MW, 0.450 MW and 0.291 MW, respectively. The corresponding values for scenario 2 were 0.615 MW, 0.507 MW, and 0.346 MW respectively. The study also considered increasing the reservoir’s live storage to 32.63Mm3 by taking part of the flood storage so that the maximum draft increases to 7 Mm3. With this upper limit of storage and draft with reservoir inflows of 50%, 75% and 90% probabilities of exceedence, the hydropower generated increased to 0.609 MW, 0.540 MW, and 0.347 MW respectively for the scenario 1 arrangement, while those of scenario 2 increased to 0.699 MW, 0.579MW and 0.406 MW respectively. The results indicate that the Doma Dam is suitable for the production of hydroelectric power and that its generation potential is between 0.61 MW and 0.70 MW.

#### Mots clés

- Doma River dam
- optimization
- integration of hydropower turbine
- power generation
- retrofitting

- Accès libre

Moisture Transfer in Concrete: Numerical Determination of the Capillary Conductivity Coefficient

Pages: 10 - 18

#### Résumé

We numerically investigated moisture transfer in buildings made of concrete. We considered three types of concrete: normal concrete, pumice concrete and cellular concrete. We present the results of a 1-D liquid water flow in such materials. We evaluated the moisture distribution in building materials using the Runge-Kutta fourth-and-fifth-order method. The DOPRI5 code was used as an integrator. The model calculated the resulting moisture content and other moisture-dependent physical parameters. The moisture curves were plotted. The dampness data obtained was utilized for the numerical computation of the coefficient of the capillary conductivity of moisture. Different profiles of this coefficient are represented. Calculations were performed for four different values of the outdoor temperature: -5°C, 0°C, 5°C and 10°C. We determined that the curves corresponding to small time intervals of wetting are associated with great amplitudes of the capillary conductivity . The amplitudes of the coefficient of the capillary conductivity decrease as the time interval increases. High outdoor temperatures induce high amplitudes of the coefficient of the capillary conductivity.

#### Mots clés

- Concrete
- Moisture content
- Diffusion
- Coefficient of the capillary conductivity
- DOPRI5 integrator

- Accès libre

Experimental Measurements of the Water Evaporation Rate of a Physical Model

Pages: 19 - 23

#### Résumé

As the number of indoor swimming pools and wellness centers are currently growing, it is necessary to concentrate on the parameters of indoor environments. These parameters are necessary for the design of the HVAC systems that operate these premises. In indoor swimming-pool facilities, the energy demand is large due to ventilation losses from exhaust air. Since water evaporates from a pool’s surface, exhaust air has a high water content and specific enthalpy. In this paper the results of the water evaporation rate measured from swimming pool surfaces at higher thermal water temperatures are described.

#### Mots clés

- Evaporation
- Swimming pool
- Physical model

- Accès libre

Choice of Appropriate Control Values for Effective Analyses of Damage Detection

Pages: 24 - 28

#### Résumé

The article is devoted to a suitable choice of input parameters for the efficient running of a self-developed code used for damage detection. The code was prepared in Office Excel VBA, which used a non-destructive vibration-based method. The primary aim of the code is to determine the change in bending stiffness by using the FE model updating method, and the aim of the paper is to determine the effect of the input data on the bending stiffness calculations. The code was applied for a numerical model of a steel bar. The steel bar was a simply supported beam with a span of 3.5 m. The time of the calculations and precision of the identification were investigated. The values of the time consumption depend on the input values, the desired limit of the accepted error, and the length of the step in every iteration. Data from an experimental model was analysed. The model was made of wooden and plaster boards. The calculations were done in accordance with suitable input data from a parametric study.

#### Mots clés

- Parametric study
- Structural health monitoring
- Damage assessment
- System identification
- FE model updating method

- Accès libre

Methods for Improvement of the Ecosystem Services of Soil by Sustainable Land Management in the Myjava River Basin

Pages: 29 - 36

#### Résumé

The main aim of this study is the development of methods for the assessment of the ecosystem services (ESS) of soils within the RECARE project and the participatory identification of measures to combat soil threats caused by floods in the Myjava River basin. The Myjava Hills highlands are known for their rapid runoff response and related muddy floods, which are determined by both the natural and socio-economic conditions. Within the frame of the mentioned project, the ESS framework with detailed relationships between the ecology, societal response, driving forces and also human well-being was identified. Next, to assess the SLM practices in the pilot basin, the stakeholders, who showed an interest in solving the flood protection problems in their areas, took an active part in the process of evaluating, scoring and selecting the best sustainable land management practices (SLM) for the flood protection of soil. From the results which were proposed, the technology of vegetative strips was top rated within the total results among all the SLM measures in all the categories, followed by water-retaining ditches and small wooden dams. Building a polder least meets the proposed SLM criteria.

#### Mots clés

- Ecosystem services
- RECARE project
- Myjava catchment
- Stakeholders
- flood protection