We present an algorithm for the adaptive control of dissolved oxygen concentration in a bioreactor, based on the agitation rate. The dynamics are represented by an incremental first-order model with variable dead-time and parameters. These are estimated on-line by a recursive least-squares identification method with a forgetting factor and a constant sensitivity. The model is employed to predict the behaviour of the dissolved oxygen concentration over a finite horizon, using an original method which requires little computation. Then, a Generalized Predictive Control optimisation strategy computes the agitation rate from the predictions and the desired set point, while gradually updating the controller smoothness. This algorithm, which requires little preliminary knowledge, has been implemented on a laboratory-scale fed-batch bioreactor for which the use of conventional controllers showed limited performance, due to the unpredictable and evolutive nature of the dynamics. The new controller proved to be robust and effective over a wide range of operating conditions, while requiring no operator adjustments.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/0168-1656(95)00101-5 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Environmental triggers and ecological implications of a harmful algal bloom in the northern Arabian/Persian Gulf: Insights into the driving forces and consequences.
Sci Total Environ
January 2025
Coastal and Marine Resources Program, Environment & Life Sciences Research Center, Kuwait Institute for Scientific Research, Salmiya 20001, Kuwait.
The Arabian/Persian Gulf, a marginal sea of the northern Indian Ocean, has been significantly impacted by human activities, leading to a rise in harmful algal blooms (HABs). This study investigates the summer blooming of an ichthyotoxic phytoflagellate Chattonella marina var. antiqua and associated fish-kill in Kuwaiti waters, connecting the events to a previous dust storm and eutrophication status in the coastal waters of the Northern Arabian Gulf (NAG).
View Article and Find Full Text PDFComparative bioactivity analysis of latex and water extract of Euphorbia gaillardotii: chemical profile, antioxidant capacity, effects on water quality, in vitro antimicrobial-cytotoxic activities, and in silico molecular docking studies.
Plant Biotechnol J
January 2025
Department of Biology, Faculty of Arts and Sciences, Çukurova University, Adana, Turkey.
The genus Euphorbia, belonging to the family Euphorbiaceae, represents a significant ethnobotanical heritage due to the diverse bioactive properties exhibited. In this study, the phytochemical composition and biological activities of latex and aerial parts of the water extract of Euphorbia gaillardotii were investigated. Phytochemical analyses were performed using gas chromatography-mass spectrometry and high-performance liquid chromatography techniques and total antioxidants, phenolics, sugars, organic acids, and aroma components were quantitatively determined.
View Article and Find Full Text PDFPakistani lignite (PLC) was thermally dissolved at 300 °C using isopropanol (IPA) to obtain a soluble portion (SP) and insoluble portion (ISP). Proximate analysis, ultimate analysis, Fourier transform infrared spectrometry (FTIR), thermogravimetric analysis (TG-DTG) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) results were compared to explore the influence of the thermal dissolution process on the pyrolysis for PLC and ISP. Results showed that the thermal dissolution process mainly dissolved some light components of low-rank coal, and more phenols, aldehydes, esters and ethers were found in the SP, indicating that low-carbon alcohols can break the ether bridge bond in coal and generate oxygen-containing organic compounds (OCOCs).
View Article and Find Full Text PDFInteractive effects of salinity, redox, and colloids on greenhouse gas production and carbon mobility in coastal wetland soils.
PLoS One
January 2025
Environmental Molecular Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, United States of America.
Coastal wetlands, including freshwater systems near large lakes, rapidly bury carbon, but less is known about how they transport carbon either to marine and lake environments or to the atmosphere as greenhouse gases (GHGs) such as carbon dioxide and methane. This study examines how GHG production and organic matter (OM) mobility in coastal wetland soils vary with the availability of oxygen and other terminal electron acceptors. We also evaluated how OM and redox-sensitive species varied across different size fractions: particulates (0.
View Article and Find Full Text PDFThe influence of thermal and hypoxia induced habitat compression on walleye (Sander vitreus) movements in a temperate lake.
Mov Ecol
January 2025
Great Lakes Laboratory for Fisheries and Aquatic Science, Fisheries and Oceans Canada, 867 Lakeshore Road, Burlington, ON, Canada.
Background: Globally, temperate lakes are experiencing increases in surface water temperatures, extended periods of summer stratification, and decreases of both surface and deep water dissolved oxygen (DO). The distribution of fish is influenced by a variety of factors, but water temperature and dissolved oxygen are known to be particularly constraining such that with climate change, fish will likely feel the "squeeze" from above and below.
Methods: This study used acoustic telemetry to explore the effects of both thermal stratification and the deoxygenation of the hypolimnion on walleye (Sander vitreus) movements in a coastal embayment in Lake Ontario.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!