The photoproduction of hydrogen by the green alga Chlorella pyrenoidosa was studied in 650-ml bubble columns made of glass with 7 cm diameter. Hydrogen was produced by adding sodium dithionite as an oxygen scavenger directly to an algal suspension. When a part of the wall of the bubble column was shaded with a sheet of plastic film impervious to light, the production rate and total volume of hydrogen increased as compared to those in the columns without partial shading. This relationship between the hydrogen photoevolution rate and the proportion of lighted region is contrary to normal photochemical reactions. This phenomenon is considered to be related to the regulation by light of the activity of the enzymes and/or the photosynthetic electron transport systems, which was examined by measuring fluorescence induction curves of dark-adapted Chlorella cells and also the distribution of light intensity within the bubble column bioreactors.
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http://dx.doi.org/10.1016/S1389-1723(04)70212-1 | DOI Listing |
Ecotoxicol Environ Saf
January 2025
UR EABX, Inrae, Cestas, France. Electronic address:
Atrazine and S-metolachlor are herbicides widely used on corn and soybean crops where they are sometimes found in concentrations of concern in nearby aquatic ecosystems, potentially affecting autotrophic organisms. The aim of this study was to investigate the response of the green algae Enallax costatus, the diatom Gomphonema parvulum and a culture of the cyanobacteria Phormidium sp. and Microcystis aeruginosa, to atrazine and S-metolachlor alone and in mixture (0, 10, 100 and 1000 µg.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Electrical Engineering, Imam Khomeini Naval Science University of Nowshahr, Nowshahr, Iran.
The maximum power delivered by a photovoltaic system is greatly influenced by atmospheric conditions such as irradiation and temperature and by surrounding objects like trees, raindrops, tall buildings, animal droppings, and clouds. The partial shading caused by these surrounding objects and the rapidly changing atmospheric parameters make maximum power point tracking (MPPT) challenging. This paper proposes a hybrid MPPT algorithm that combines the benefits of the salp swarm algorithm (SSA) and hill climbing (HC) techniques.
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December 2024
Division of Sustainable Development, College of Science and Engineering, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar.
As electric vehicles gain popularity, there has been a lot of interest in supporting their continued development with the aim of enhancing their dependability, environmental advantages, and charging efficiency. The scheduling of navigation and charging for electric vehicles is among the most well-known research topics. For optimal navigation and charging scheduling, the coupled network state between the transportation and power networks must be met; moreover, the scheduling outcomes might significantly impact these networks.
View Article and Find Full Text PDFClin Oral Investig
December 2024
Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, D-80336, Munich, Germany.
Objectives: To assess the clinical performance of tooth-supported 3-unit fixed dental prostheses (FDPs) made from shade-graded monolithic 5Y-PSZ (partly stabilized zirconia) zirconia in terms of survival rate and the quality of restorations based on modified FDI criteria over three-years.
Materials And Methods: High-translucent shade-graded monolithic zirconia (Lava Esthetic, Solventum Dental Solutions) was used to manufacture maxillary or mandibular three-unit FDPs in the posterior region (N = 22) employing subtractive milling system (Amann Girrbach). All FDPs were bonded with a universal resin cement (Rely X Universal, Solventum Dental Solutions) and evaluated 4 weeks after cementation (baseline) and after 1, 2, and 3 years.
Heliyon
October 2024
Department of Electrical and Electronics Engineering, Batman University, Batman, 72100, Turkey.
Maximum Power Point Tracking (MPPT) algorithms are crucial for maximizing power extraction from photovoltaic (PV) systems. Traditional MPPT methods often exhibit suboptimal performance under partial shading conditions. Hence, advanced MPPT algorithms have been developed to enhance efficiency in such scenarios.
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