Research Article
Time Series Analysis of Rainfall Distribution in Gambella Meteorological Station
Issue:
Volume 12, Issue 1, February 2026
Pages:
1-8
Received:
11 December 2025
Accepted:
6 January 2026
Published:
27 January 2026
Abstract: This study conducted on this research on the Time Series Analysis of rainfall distribution in Gambella meteorological station. On this study, we try to see what the rainfall behavior of Gambella meteorological station seems like. In our study we have used time series model and focused on time series component, to deal variation and trend of rain fall distribution in Gambella metrological station, First, we have seen the actual data of rainfall in mm of the last ten years. The data shows a little change the year. When we see the trend value of the last ten years of the rain it is proportionally a little increasing. From the seasonal indices we have seen there was higher rainfall in the beginning of the years that means the earliest time and it shows proportionally decreasing except 2009 was higher rainfall. Lastly we seen the forecasted value for 2013 based on the rainfall of 2012 rainfall and the forecasted value of rainfall in Gambella meteorological is similar to that of its preceding years, but it will show a little decreasing at the beginning of the year and it will be constant.
Abstract: This study conducted on this research on the Time Series Analysis of rainfall distribution in Gambella meteorological station. On this study, we try to see what the rainfall behavior of Gambella meteorological station seems like. In our study we have used time series model and focused on time series component, to deal variation and trend of rain fa...
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Research Article
Tortuosity and Species Transport in PEM Fuel Cells Gas Diffusion Layers
Issue:
Volume 12, Issue 1, February 2026
Pages:
9-25
Received:
27 January 2026
Accepted:
25 February 2026
Published:
9 March 2026
Abstract: Proton Exchange Membrane (PEM) fuel cells are electrochemical devices that directly convert chemical energy of hydrogen into electricity, offering high efficiency and low environmental impact. Among the key components of PEM fuel cells, the Gas Diffusion Layer (GDL) plays a critical role in facilitating the transport of reactant gases and in ensuring uniform current distribution across the cell. This study investigates the influence of GDL tortuosity, a structural parameter characterizing the complexity of diffusion pathways on PEM fuel cells performances. COMSOL Multiphysics was used to develop numerical model and simulate the effects of isotropic and anisotropic tortuosity on (a) species transport and (b) current density distribution within the cell. The results indicate that higher tortuosity significantly impedes reactant diffusion, leading to performance degradation, especially under low current density. Polarization curves’ analysis confirms a marked decline in cell output with increased values of tortuosity. Furthermore, the study reveals that anisotropic tortuosity introduces non-uniform diffusion patters, affecting cells efficiency. These findings highlight the critical importance of GDL microstructure in PEM fuel cells design and suggest that optimizing tortuosity, alongside other parameters such as porosity, gas pressure, and conductivity, is essential for improving cells’ durability and performance in practical applications.
Abstract: Proton Exchange Membrane (PEM) fuel cells are electrochemical devices that directly convert chemical energy of hydrogen into electricity, offering high efficiency and low environmental impact. Among the key components of PEM fuel cells, the Gas Diffusion Layer (GDL) plays a critical role in facilitating the transport of reactant gases and in ensuri...
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,
Abiyot Abebaw
