Oxygen sensors model

Fig. 6. Root haemoglobin as an oxygen sensor. Model for root haemoglobin sensing oxygen levels and inducing the anaerobic response. There could be many more steps in this pathway than shown in the figure.

Many types of oxygen sensor models have been proposed. (3.-8)... 

Sensor voltage characteristics of the crucible type oxygen sensor. According to the oxygen sensor model used in this analysis, the oxygen partial pressure Po2(0) at the measurement electrode can be expressed by Equations 28- 32, 3, and 35. Calculated results for the sensor voltage are shown in Figure 9-... 

Oxygen sensors, in low volume use as part of a closed loop emission control system for automotive applications since 1977, have seen wide-spread use starting with the 1981 model year. At the present time, a partially stabilized zirconia electrolyte using yttrium oxide as the stabilizer appears to be the most common choice for this application. 

W. J. Fleming, Zirconia Oxygen Sensor—An Equivalent Circuit Model, SAE 800020, Society of Automotive Engineers, Warrendale, Pa., 1980. 

In the case of a larger sensor current, the model for the thick film oxygen sensor used in this analysis showed favorable possibilities for a "lean oxygen sensor."... 

A schematic representation of how a decrease in oxygen tension (hypoxia) may affect carotid body glomus cell function. In the mitochondrial model, hypoxia affects either reactive oxygen species (ROS) production or ATP production of mitochondria. Both of these may affect the outward flux of potassium via the potassium channel with the downstream effects shown in the diagram. In the membrane model, the ROS production by membrane-bound molecules (cytochromes) is oxygen sensitive, and thereby affected by hypoxia. Thus, these membrane-bound molecules function as proximal oxygen sensors and cause effects on potassium channels with the downstream effects described in the figure and in the text... 

Synthesis and characterization of a model Cu0/Sn02 oxygen sensor... 

FIGURE 2.3 Schematic presentation of the interaction of the solid electrolyte oxygen sensor with gas environment 1-6 stages of interaction. (From Zhniykov, S., Mathematical model of electrochemical gas sensors with distributed temporal and spatial parameters and its transformation to models of the real YSZ-based sensors. Ionics 12 (2006) 135-148. With kind permission of Springer Science and Business Media.)... 

The initial sensors and subsequent signal transduction systems of hypoxic vasoconstriction (HPV) remain an area of intense investigation (21,22). At the cellular level, pulmonary artery smooth muscle (PASM) contraction depends on an increase in cytosolic calcium from the extracellular space as well as release from intracellular stores, and membrane depolarization due to closure of K+ channels. Many argue that the mitochondria is a primary oxygen sensor such that electron transport chain inhibitors can specifically inhibit HPV and/or prevent the hypoxia-specific response. Reactive oxygen species are also implicated in HPV. Two different models are proposed one describes an increase in mitochondrial ROS mediated via increased intracellular calcium release, and the second describes a decrease in mitochondrial ROS mediated via inhibition of the Kv channel (Figure 8.2). 

Unvented Heater - A combustion heating appliance that vents the combustion by-products directly into the heated space. The latest models have oxygen-sensors that shut off the unit when the oxygen level In the room falls below a safe level. 

This very simple model having the adsorbed layer formed on the surfaces of the electrode and the electrolyte has allowed us to successfully interpret the response time of oxygen sensors systematically measured under various conditions and the deviations from ideal behavior due to the oxygen semipermeability flux [10,11]. The existence of the adsorbed layer becomes the most important factor to determine the response characteristics of the device to the oxygen pressure. 

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