Oxygen dissolved, monitoring

Periodic samples were taken at the starting point after introducing the inocula, on the fust, second and thud day of each experimental ran. The optical cell density, COD, carbohydrate concentration and dissolved oxygen were monitored for various air flow rates. The COD was measured by the closed reflux colorimetric method at 600 nm with a spectrophotometer using potassium dichromate as a reducing reagent.7 All organic chemicals... 

The amounts of C02 produced by respiration of oxygen are monitored from the depletion of dissolved oxygen along the flow path. The amount of C02 produced... 

The structure and behavior of methyl radicals on surfaces was compared with that in aqueous solution. Methyl radicals were produced and characterized by EPR in a fast-mixing flow system of Ti(III) with tertiary butyl hydroperoxide.(133) As a side investigation, the reaction of methyl radicals with oxygen dissolved in water was monitored not only by EPR but by chemiluminescence using an electronic image intensifier.(134)... 

ORR measurement, either pure oxygen or air is used to purge the electrolyte solution to make oxygen dissolved in the solution. In addition, there is a thermometer port to monitor the temperature of the electrolyte solution. Both the heating/cooling liquid inlet tind outlet are used for controlling the cell s temperature at the desired level. 

Fish can only survive in fresh water because of the oxygen dissolved in it. Hence it is important to monitor the dissolved oxygen concentration. If this is less than 5 mgdm" then most species of fish cannot survive. 

Figure L The microdialysis based glucose monitoring system with the silicon lamella structure operating as the enzyme reactor. The oxygen electrode monitored the changes in dissolved oxygen as the dialysis probe was immersed into samples of varying glucose concentrations.

Closed bottle test OECD 301D [25], ISO 10707 [26]. Based on oxygen consumption, monitoring of decrease in dissolved oxygen. 

Oxygen pitting of boiler tubes by boiler feed water due to inadequate de-aeration is also a problem, but controllable by proper maintenance of de-aerators, coupled with regular boiler feed water analysis, or, preferably, continuous dissolved-oxygen monitoring. 

The apparatus is sometimes referred to as an oxygen electrode , but it is actually a cell. Although the Teflon membrane is impermeable to water and, therefore, to most substances dissolved in water, dissolved gases can pass through, and gases, such as chlorine, sulphur dioxide and hydrogen sulphide, can affect the electrode. The apparatus can be made readily portable and it is, therefore, of value for use in the field and can be used to monitor the oxygen content of rivers and lakes (see Ref. 53). 

In biochemical engineering processes, measurement of dissolved oxygen (DO) is essential. The production of SCP may reach a steady-state condition by keeping the DO level constant, while the viable protein is continuously harvested. The concentration of protein is proportional to oxygen uptake rate. Control of DO would lead us to achieve steady SCP production. Variation of DO may affect retention time and other process variables such as substrate and product concentrations, retention time, dilution rate and aeration rate. Microbial activities are monitored by the oxygen uptake rate from the supplied ah or oxygen. 

Water treatment monitoring and control is often a knife-edge operation and must be tailored to the overall operation of the boiler because waterside and gas-side problems usually are interlinked. Consequently (and as with other types of WT boiler), not only should the utility boiler FW be essentially free of dissolved oxygen to prevent waterside pitting corrosion of the economizer and other boiler components, but also the temperature must be high enough to prevent dewpoint condensation and subsequent acid attack on the gas side of the economizer tubes. 

The organization for Economic Co-operation and Development publishes a compendium on environmental data including river monitoring, also on a biannual basis. The most recent edition includes 5 year incremental data from 1970 through 1985 for chromium, copper, lead, cadmium, ammonia, nitrate, phosphorous, dissolved oxygen and biochemical oxygen demand 28),... 

A DSS tool for the dissolved oxygen real time monitoring integrating the HIDRO (for hydrodynamics) and QUAL (for the description of conservative and nonconservative parameters) has been developed for the river San Joaquin in... 

The DAC system consisted of computer, interface cards, meters, transmitters, and solid state relays (SSR). Electrodes of pH (Ingold), Oxidation-Reduction Potential (Cole-Parmer), and Dissolved Oxygen (Ingold) were installed and connected to individual meter. The status of reactor and the value of electrode signal were displayed in a computer monitor, and stored in data file. 

In a typical experiment by the dynamic gassing-in/gassing-out method during the normal operation of the plant, the air supply is shut off and the dissolved oxygen (DO) concentration is monitored as the DO is depleted. The dissolved oxygen dynamics during the gassing-out part of the experiment are described by... 

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