A Fibre Optic Micro-Optrode For Dissolved Oxygen Measurements

1997 ◽  
Author(s):  
Scott McCulloch ◽  
Deepak Uttamchandani
Keyword(s):  
Dissolved Oxygen ◽  
Fibre Optic ◽  
Oxygen Measurements

Fibre optic micro-optrode for dissolved oxygen measurements

1999 ◽  
Vol 146 (3) ◽  
pp. 123-127 ◽  
Author(s):  
S. McCulloch ◽  
D. Uttamchandani
Keyword(s):  
Dissolved Oxygen ◽  
Fibre Optic ◽  
Oxygen Measurements

Natural Dynamics and Control of Soil Gas Oxygen in Wetlands: Fibre-Optic Oxygen Measurements at Two Field Sites in the Doñana National Park (Spain)

Wetlands ◽  
2014 ◽  
Vol 34 (6) ◽  
pp. 1197-1206 ◽  
Author(s):  
Claus Kohfahl ◽  
Natalia Fernández de los Santos ◽  
Carlos Mediavilla Laso ◽  
Antonio Martínez Sánchez de la Nieta ◽  
Fernando Ruiz Bermudo
Keyword(s):  
National Park ◽  
Soil Gas ◽  
Fibre Optic ◽  
Doñana National Park ◽  
Dynamics And Control ◽  
Natural Dynamics ◽  
And Control ◽  
Oxygen Measurements

A Novel Acoustic Dissolved Oxygen Transmitter for Fish Telemetry

2006 ◽  
Vol 40 (1) ◽  
pp. 103-108 ◽  
Author(s):  
Jon C. Svendsen ◽  
Kim Aarestrup ◽  
John F. Steffensen ◽  
Jannik Herskin
Keyword(s):  
Dissolved Oxygen ◽  
Response Time ◽  
Oxygen Saturation ◽  
Ambient Temperature ◽  
Entire Range ◽  
High Accuracy ◽  
Field Observations ◽  
Different Temperatures ◽  
Fish Telemetry ◽  
Oxygen Measurements

The multiple responses of fishes to changes in dissolved oxygen saturations have been studied widely in the laboratory. In contrast, only a few studies have included field observations. The objective of the present study was to evaluate the performance of a novel acoustic dissolved oxygen transmitter for field biotelemetry. The results demonstrated that the output of the transmitter was unaffected by three different temperatures (10 to 30°C) and described the dissolved oxygen saturation with high accuracy (r2 > 0.99) over the entire range of 0 to 191% saturation. The response time (≥ 90% of end value) of the transmitter was 12 s both in terms of decreasing (100 to 0%) and increasing (0 to 100%) oxygen saturations. When externally attached to fishes, the present findings support the use of the transmitter for reliable dissolved oxygen measurements on individuals living in environments that may change both temporally and spatially with regard to ambient temperature and dissolved oxygen saturation.

Activated Sludge Process Control Using Dissolved Oxygen Measurements

1984 ◽  
Vol 16 (5-7) ◽  
pp. 613-620 ◽  
Author(s):  
S Marsili-Libelli
Keyword(s):  
Dissolved Oxygen ◽  
Simulation Analysis ◽  
Dynamic Balance ◽  
Utilization Rate ◽  
Oxygen Utilization ◽  
Output Controller ◽  
Combined Estimation ◽  
Aerobic Reactor ◽  
Oxygen Utilization Rate ◽  
Oxygen Measurements

This paper describes a combined estimation/control scheme conceived to handle unmeasurable process quantities, such as viable mass in the aerobic reactor. Starting with the well known dissolved oxygen dynamic balance, an algorithm for the reconstruction of the oxygen utilization rate is derived, which in turn is used to mechanize a nonlinear state observer for the process variables. Eventually this cascaded double observer is coupled to a digital PID controller, thus forming an overall output controller based solely on dissolved oxygen measurements. Simulation analysis is used to assess the composite output controller performance and sensitivity.

scholarly journals Long-Term Performance of Aanderaa Optodes and Sea-Bird SBE-43 Dissolved-Oxygen Sensors Bottom Mounted at 32 m in Massachusetts Bay

2007 ◽  
Vol 24 (11) ◽  
pp. 1924-1935 ◽  
Author(s):  
Marinna Martini ◽  
Bradford Butman ◽  
Michael J. Mickelson
Keyword(s):  
Dissolved Oxygen ◽  
Correlation Coefficient ◽  
Field Evaluation ◽  
Mean Difference ◽  
Massachusetts Bay ◽  
The Mean ◽  
The Difference ◽  
Long Term Performance ◽  
Term Performance ◽  
Oxygen Measurements

Abstract A field evaluation of two new dissolved-oxygen sensing technologies, the Aanderaa Instruments AS optode model 3830 and the Sea-Bird Electronics, Inc., model SBE43, was carried out at about 32-m water depth in western Massachusetts Bay. The optode is an optical sensor that measures fluorescence quenching by oxygen molecules, while the SBE43 is a Clark polarographic membrane sensor. Optodes were continuously deployed on bottom tripod frames by exchanging sensors every 4 months over a 19-month period. A Sea-Bird SBE43 was added during one 4-month deployment. These moored observations compared well with oxygen measurements from profiles collected during monthly shipboard surveys conducted by the Massachusetts Water Resources Authority. The mean correlation coefficient between the moored measurements and shipboard survey data was >0.9, the mean difference was 0.06 mL L−1, and the standard deviation of the difference was 0.15 mL L−1. The correlation coefficient between the optode and the SBE43 was >0.9 and the mean difference was 0.07 mL L−1. Optode measurements degraded when fouling was severe enough to block oxygen molecules from entering the sensing foil over a significant portion of the sensing window. Drift observed in two optodes beginning at about 225 and 390 days of deployment is attributed to degradation of the sensing foil. Flushing is necessary to equilibrate the Sea-Bird sensor. Power consumption by the SBE43 and required pump was 19.2 mWh per sample, and the optode consumed 0.9 mWh per sample, both within expected values based on manufacturers’ specifications.

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