We construct the two unique piecewise C3-splines of degree six and eight to approximate the solution of fractional integro-differential equations. Existence and uniqueness of the solution of second ...order fractional integro-differential equation has been proved. Convergence analysis of the presented methods have been discussed. Illustrative examples are included to demonstrate the validity and applicability of the presented approaches.
This study is dedicated to the examination of cavitation-induced erosion, a critical factor in optimizing the efficiency of hydraulic systems, including hydropower plants and pumping systems. To ...accomplish this, we conducted a sensitivity analysis utilizing a cavitation jet apparatus (CJA) and an experimental configuration that featured a vertical cylindrical test tank, a submerged nozzle, and an aluminum sample (specifically, alloy 6351 T6). The study maintained a consistent standoff distance of 5 cm and an orifice diameter of 2 × 10-3 m. Two distinct nozzle geometries were tested to assess their influence on cavitation erosion. The outcomes revealed that the 20° conical sharped-edges nozzle resulted in the highest erosion rates, while the commercial nozzle (MEG 2510) caused comparatively less erosion. By standardizing the test duration to 1200 seconds and using a cavitation index of 0.14, the researchers avoided overlapping pits. In summary, the CJA, with these adjustments, demonstrated its effectiveness as a tool for evaluating the resistance of solid surfaces to cavitation.
Este estudo é dedicado ao exame da erosão induzida por cavitação, um fator crítico na otimização da eficiência de sistemas hidráulicos, incluindo usinas hidrelétricas e sistemas de bombeamento. Para isso, realizamos uma análise de sensibilidade utilizando um aparelho de jato de cavitação (CJA) e uma configuração experimental que apresentava um tanque de teste cilíndrico vertical, um bico submerso e uma amostra de alumínio (especificamente, liga 6351 T6). O estudo manteve uma distância consistente de 5 cm e um diâmetro de orifício de 2 × 10-3 m. Duas geometrias distintas de bicos foram testadas para avaliar sua influência na erosão por cavitação. Os resultados revelaram que o bocal cônico com bordas afiadas de 20° resultou nas maiores taxas de erosão, enquanto o bocal comercial (MEG 2510) causou comparativamente menos erosão. Ao padronizar a duração do teste para 1.200 segundos e usar um índice de cavitação de 0,14, os pesquisadores evitaram a sobreposição de poços. Em resumo, o CJA, com esses ajustes, demonstrou sua eficácia como ferramenta de avaliação da resistência de superfícies sólidas à cavitação.
...this study represents a significant advancement in the realm of hydrological modeling within the Pantanal region. ...the insights gained from the utilization of LSTM in addressing data scarcity ...challenges can offer valuable implications for analogous circumstances in other regions globally. ...accurate hydrological modeling is indispensable for understanding the response of wetland ecosystems to environmental changes, ensuring their conservation, and supporting the communities dependent on these regions for their livelihoods. The Pantanal, with its vast floodplain and extensive network of rivers, exemplifies the intricate interplay between wetland hydrology and ecosystem health. ...gaining insights into the hydrological dynamics of the Pantanal, and wetlands in general, is essential for sustainable environmental management, particularly in the face of changing climate conditions.
This article demonstrates the successful application of Long Short-Term Memory (LSTM) recurrent neural networks to simulate streamflow in the Aquidauana River basin, located in the Brazilian ...Pantanal. The LSTM network used daily precipitation data as input to predict future streamflow in the region. The results obtained from this research show a coefficient of determination (R2) of 0.82, indicating a strong fit of the model to the observed data. Additionally, the Root Mean Squared Error (RMSE) was found to be 0.53, indicating the model's accuracy in predicting streamflow compared to actual data. These findings highlight the effectiveness of LSTM networks in hydrological modeling for the Pantanal region, which is crucial for water resource planning and sustainable management in this ecologically significant area. This study is expected to serve as a catalyst for further research and make a substantial contribution to the advancement of streamflow prediction techniques in complex watersheds such as the Aquidauana River basin.
Este artigo mostra uma aplicação bem-sucedida de rede neural recorrente - Long Short-Term Memory (LSTM), para simular a vazão na bacia do rio Aquidauana, dentro dos limites do Pantanal brasileiro. Os dados diários de precipitação serviram como variáveis de entrada para permitir que a rede LSTM previsse o fluxo futuro na região. Os resultados obtidos demonstram um coeficiente de determinação (R2) de 0,82, indicando um ajuste favorável do modelo aos dados observados, juntamente com um erro quadrático médio (RMSE) de 0,53, demonstrando precisão na previsão do modelo em comparação com a vazão real. Tais métricas ressaltam a eficiência das redes LSTM para modelagem hidrológica na região do Pantanal, um aspecto crucial para o planejamento e gestão sustentável dos recursos hídricos na área. Espera-se que este estudo inspire novas pesquisas e contribua significativamente para o avanço das técnicas de previsão de vazões em bacias hidrográficas complexas e com deficiência de dados, como a bacia do Rio Aquidauana.
In this research, mechanical and structural properties of Continuous Fiber Reinforced Additively Manufactured (CFRAM) components are studied. Structural analysis is performed to understand the ...failure behavior of CFRAM components. Based on the SEM analysis of the tested parts, correlations between results of the mechanical test and microstructure of the parts have been investigated. CFRAM components are lightweight yet strong materials with a wide range of potential applications in auto industry, aerospace, sport goods, and medical tools. CFRAM components benefit from both cutting-edge 3D printing technology and fiber reinforcement to improve mechanical properties. Produced parts have lightweight compared with metals, strong mechanical properties, and short manufacturing time. In addition, thermoplastic polymer used for CFRAM components makes product recyclable. In this study, samples were printed using Markforged Mark Two printer and the effect of the fiber type, fiber orientations, infill density, and temperatures on tensile, fatigue, and creep properties were investigated. Carbon fiber (CF), fiberglass (FG), and Kevlar were used as reinforcing agents, and nylon as the base material. Microstructural analysis was conducted to investigate the fracture mechanism, morphology, and printing quality of the specimens. It was observed that the main failing mechanisms for CFRAM components are fiber pull-out, fiber breakage, and delamination. Further, it was understood that there is a correlation between the fiber stacking density and mechanical properties. Overall, the information provided in this study reports a unique knowledge base about the mechanical and structural behaviours of the components built with the CFRAM technology.
•Thin layers of anatase titanium dioxide were coated on glass by spray pyrolysis method.•The layers were hydrogenated by DC plasma from room temperature up to 350°C.•Band gap of the layers was ...decreased 0.13eV by plasma treatment at highest temperature.•There is a specific plasma temperature range, which hydrophilicity and photocatalytic properties of the layers are optimum.
Thin layers of anatase titanium dioxide were coated on glass by spray pyrolysis method. The layers were hydrogenated by DC plasma from room temperature up to 350°C. Hydrogen plasma treatment at low temperatures, leads to decrease the surface roughness, while surface roughness is increased by enhancing plasma temperature. Layers’ band gap was decreased 0.13eV by plasma treatment at highest temperature. Hydrophilicity and photocatalytic properties of the layers under plasma treatment at 150 and 200°C, were improved noticeably. However, plasma treatment at temperatures above 200°C was lead to decrease hydrophilicity and photocatalytic activity of TiO2 layers. The reason seems formation of oxygen vacancies in the interior layers that act as charge carriers’ recombination centers.
The aim of this research is the study of self-cleaning and antibacterial activity of
SiO
2
/TiO
2
thinfilm contains copper in it on ordinary ceramic tiles substrates. Four solutions using the sol-gel ...method with various volume ratio of Si/Ti precursors (i.e., 1/9, 2/8, 3/7, and 4/6) were prepared. Then, they were deposited on the ceramic tiles via the dip-coating technique and heated through thermal treatment at 650° for an hour. The XRD results show anatase and rutile structures are the main phases in the composite films of Cu
/SiO
2
/TiO
2
coatings. The rms roughness obtained by AFM for ceramic tile was initially ~20 nm, which reduced to <2 nm after deposition. The SEM images, depicted a uniform and crack-free thin-film coating with a thickness <30 nm. Stearic acid coating was applied on the samples as a pollution and was completely removed after being subjected to 24 hrs of UV illumination (400–800 μW/
cm
2
) in an environment with low and variable humidity (21–37 RH). About 76° reduction of water contact angle (WCA) was observed during photocatalytic test for the 1/9 (optimum) sample. In addition, a 33° decrease in WCA was measured in the light-induced hydrophilicity experiment. The 1/9 sample that reacted mostly under UV illumination in both photocatalytic and light-induced hydrophilicity was concluded as the optimum one. To improve the antibacterial property of the coating, copper nitrate trihydrate was added to the 1/9 solution. Moreover, antibacterial test was performed through “viable cell count” method by E. coli bacteria. The results of antibacterial test showed a 99% and 99.99% reduction in the number of E. coli bacteria during 1 and 24 hrs intervals, respectively. This is, surprisingly, to the best of our knowledge, the same as the results that can be obtained using silver nanoparticles.
Graphical abstract
Highlights
Self-cleaning take place before 24 hours under a very weak UV illumination.
Elimination of 99% and 99.99% of E. coli bacteria within 1 and 24 hours of using Cu instead of Ag.
Self-clean and antibacterial thin-film coating which is commercially affordable rather than using detergent materials.
No visible changes have been observed in the design or color of ceramic tiles.
Applicable to use in different environments with variable climate conditions.
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