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Analysis of the Changes in the Mechanical Properties of Branches of Salix Energy Plants After Shearing
As a result of the energy crisis due, among other things, to climate change, most developed countries have taken steps with the main aim—among other things—of increasing the use of green energy sources that do not rely on fuels (including primarily liquid fuels) but use renewable energies. Plant biomass is a versatile substrate that can be used in many areas of the economy and production, but also for the production of various types of fuel. These range from rapeseed oil used as a component of biodiesel or maize starch for ethanol production to typically cellulosic plants such as energy willow, which can be used for direct combustion. The floodplain is home to this type of vegetation. It is characterized by great diversity in terms of geometric dimensions and mechanical and morphological properties. In addition, the location (easy access to water and sunlight) influences its potential energy value. Vegetation, thanks to favorable conditions, can achieve large weight gains in a relatively short period of time. Therefore, its properties should be carefully recognized in order to make more efficient use of energy and operating equipment used during harvesting. This paper presents an analysis of the changes in the elasticity of willow branches over a period of 16 days following harvesting. The changes were analyzed for branches taken from three different shrubs at three different plant height levels during the post-growth period. Based on the measurements carried out, the elastic modulus E of the shoots was estimated. The average modulus of elasticity ranged from about 4500 two days after cutting to about 5500 MPa 16 days after cutting and showed high variability, reaching even CV = 37%, both within a given shrub and depending on the measurement date. The results presented here indicate a high natural variability of mechanical parameters even within the same plant.
Assessing the feasibility of using Machine learning algorithms to determine reservoir water quality based on a reduced set of predictors
Fuzzy analytical hierarchy process methods in changing the damming level of a small hydropower plant: Case study of Rosko SHP in Poland
Application of Physical and Numerical Modeling for Determination of Waterway Safety under the Bridge in Kaunas City, Lithuania
The main problem presented in this paper is the safety inlet navigation of the waterway below the bridge in the city of Kaunas in Lithuania. The analyzed reach is located in the Nemunas river downstream of the Kaunas dam. It is a part of the waterway E–41 leading to the Klaipeda harbor on the southern coast of the Baltic Sea. The work was initiated by the Lithuanian company UAB “Inžinerinis projektavimas” with funds from the project called European Union Trans-European Transport Network (EU TEN-T). The main requirement imposed along this reach is to keep sufficient depth even in the range of the lowest flows. The depth is sufficient if it is not lower than 1.15 m for minimum flows such as Q95% and Q95% with ice. The hydraulic conditions for maximum flow Q50%, Q5%, and Q1% are also taken into account for control because the threat of hydraulic jump generation was also noticed. The research is based on georeferenced data from public and non-public sources. The hydrologic data were received from the Lithuanian Hydrometeorological Service. The physical model was created in the Water Laboratory of the Department of Hydraulic and Sanitary Engineering at Poznan University of Life Sciences, Poland. The preprocessing of spatial data in ArcGIS 10.8.2 and rules of hydraulic similarity were implemented in the process of physical model preparation. Three experiments were conducted in the laboratory with scaled values of Q95%, Q5%, and Q1%. The measurements of the water surface and evaluations of the average velocity were used to validate the 2D numerical model prepared in HEC-RAS 6.3.1. The basic layers of the HEC-RAS model were preprocessed in ArcGIS 10.8.2 by ESRI company. The numerical model was implemented to test different values of unknown roughness of the channel bottom. The simulations were conducted for the real values of Q95% and Q95% with ice and Q50%. The results of the simulations were depth and Froude number maps. These maps were classified into zones of no risk, middle risk, and high risk. ArcGIS in the post-processing phase was applied to identify the locations of the hazards. The magnitude of risk was expressed in terms of minimum depth achieved, maximum Froude number, as well as the length of the reaches with high risk related to these two factors. The threat of hydraulic jump formation below the bridge was also noticed. Conducted results confirmed that the combination of hydrodynamic simulations and geoprocessing in the pre- and post-processing stages could be a powerful tool in hydraulic engineering analyses. Additionally, it is worth noting that numerical modeling enables a wider analysis of potential conditions than could be possible with a physical model only.
Analysis of the Influence of Hydraulic and Hydrological Factors on the Operating Conditions of a Small Hydropower Station on the Example of the Stary Młyn Barrage on the Głomia River in Poland
The operation of water structures causes various problems. They are related, for example, to the material carried by the water, hydrological conditions, range of operation of hydroelectric turbines, or water elevations at the lower position of the hydroelectric power plant. Among the various operational problems, this article focuses mainly on the impact of the backwater of Gwda river on the water level elevations at the lower station of the Stary Młyn hydropower plant in Dobrzyca. The power plant is located on Głomia river. The analysis was carried out for different flow variants in both the Gwda and Głomia rivers. The effect of characteristic flows on the water surface level at the lower station of the hydropower plant was examined. It was found that the water surface level at the lower station of the hydropower plant is strongly influenced by flows higher than the average high flow on Gwda river. Due to the extent of the backwater in current operating conditions, the hydroelectric power plant is shut down from flows on Gwda river of 30–28 m3/s (flows that are not much higher than the multi-year average SSQ). The modeling results were confirmed by an analysis of power plant shutdowns of normal operation especially in wet years, when the plant did not operate for almost half of the year (188 days), with losses of 203 MWh. It was also shown that even a small additional damming of water, e.g., of the order of 0.2 m, can extend the operating time of a power plant up to 249 days even under unfavorable hydrological conditions. Factors related to climate change are beginning to play an increasingly important role in the current operating conditions of small lowland hydroelectric power plants. They can contribute to a reduction in electricity production. The proposed solution related to the possibility of greater water retention on dammed-up water barrages allows one to partially offset these problems as well.
The Influence of Fibers from Domestic Laundry Wastewater on the Clogging Process of a Filter
This study presents the impact of the size and shape of particles in laundry wastewater on the clogging process of a porous material. Clogging can be defined as a mechanical limitation of flow through porous media. The process of mechanical clogging was investigated in this study. The research was conducted in laboratory conditions in a filter column filled with glass beads whose diameter corresponded to coarse sand. The results reveal the influence of graywater quality on filter hydraulic conductivity and bed clogging, showing the impact of fiber particles in wastewater (sewage from home laundry) on the clogging process in soil. The results confirm that fiber particles significantly reduce filter permeability, particularly due to the formation of a filter cake. As analyzed in this paper, the distribution of quantitative data on particles of different sizes found in laundry wastewater indicates that they mainly accumulate in the upper layer, where particles with fiber lengths ranging from 0 to 1600 µm can be found. The average length of the fibers decreased with increasing depth. At a depth of approximately 10 cm, fibers with dimensions in the range of 0 to 100 μm were predominantly observed.