Factors Affecting Sensor Performance

Apart from these, the detailed physical form of the sensor can also have an important influence on selectivity. The target gas has to diffuse through the microporous sensor material toward the sensing electrodes. The diffusion rate will depend on the mean free path of the gas molecules in relation to the diameter of the channels in the solid. 

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Progress continues to be made toward the development of practical vapor detection instruments using coated SAW sensors. This paper reviews some of the characteristics of these versatile devices and their current capabilities. Factors affecting sensor performance, such as temperature and coating selection, are considered in terms of the sensitivity and selectivity of the SAW device. Special attention is given to a 4-SAW array instrument that is able to "fingerprint" and identify a variety of chemical vapors. 

There are various factors affecting the performance of a WIM system. Some of them are related to the selected device, particularly the weight sensors used and related technology. However, the performance of a WIM system is greatly affected by the choice of the WIM site and the environmental characteristics at the selected site. In relation to the choice of site, the location and road geometry, the pavement characteristics are of great importance as well. 

Liu G, Nguyen QT, Chow E, Bocking T, Hibbert DB, Gooding JJ (2006) Study of factors affecting the performance of voltammetric copper sensors based on Gly-Gly-His modified glassy carbon and gold electrodes. Electroanalysis 18 1141-1151... 

This property has important implications on the characteristics of the biosensor, particularly as related to the supply rate of the analyte to the sensor. Thus for small sample volumes, the analyte may be depleted in the region of the sensor. Further, factors that affect the delivery of the analyte to the sensor, e.g. fouling of the sensor surface, can affect the sensor performance. The bioreceptors identified with cell signaling in immunology and pharmacology are usually nonconsuming in nature, and thus have fewer potential problems due to artifacts related to analyte consumption. 

Determine the factors affecting the stability and performance of thin fdm sensors in practical environments. 

The factors that affect the performance of H2O2 biosensor are (i) the type of enzyme, (ii) the immol sation method, and (iii) the thickness of the created enzyme layer. Immobilisation processes are quite an important Eictor for the development of biosensors. This step has been smdied extensively, in order to achieve easy operation, quick measurement and reduce the cost of the analysis. The methods of enzymes immobilisation used for the development of hydrogen peroxide sensors can be divided into five major groups (Fig. 3) ... 

This article explains basic properties of Sn02 as a semiconductor gas sensor material and then discusses several factors affecting its gas-sensing properties. New approaches and challenges directed to further improving the gas-sensing performance are also introduced briefly. 

Several factors may affect the performance of EC sensors. Enviromnental conditions are major concerns. During operation in high-hnmidity conditions, the cell electrolyte may absorb water from the air. In contrasL while operating in low-humidity conditions, the cell electrolyte may lose water. This gain and loss of water... 

In harsh operational conditions environmental factors can affect the performance of DP which can lead to loss of the position control abiUty. For a Mobile Offshore Drilling Unit (MODU), loss of position without safe disconnection could result in critical damage not only to the well, but also to the subsea equipment. For an Offshore Support Vessel (OSV), loss of position could lead to colhsion with the nearby installation during operation or to damage to the subsea fadhties. In order to increase the safety and reliabiUty of a DP system, it is important to identify and quantify all influence factors and the way that they can affect the DP performance. For example bad weather condition is an effective factor on the position reference sensor or the local position reference system. Such operational conditions can vary from place to place and may have a dynamic nature in a specific location. Moreover, it is important to investigate safe recovery back to position, safe disconnection and reconnection when the loss of position is outside the safe operational range. 

When constmcting biosensors from cells and tissues there can be several factors that can affect the performance of the sensor. The amount of cells immobilized, the type of membrane used, the degree of polymerization, and the amount of cross-linking agent can also influence the performance of the biosensor. Additionally, the pH, composition, and temperature of the solution tested can influence the biosensor performance dramatically. Even small changes in pH can reduce the enzymatic activity, which is often a function of pH, or even irreversibly destroy the cells or tissues. Furthermore, the composition of the solution is important as certain compounds could inhibit the enzymatic function. 

After each of the components has been evaluated and corrected wherever possible, the closed-loop system should be checked. From an overall point of view, there are three general factors that affect the closed-loop performance of a control loop (1) the type and magnitude of disturbances, (2) the lag associated with the components that compose the control loop, and (3) the precision to which each component of the control loop performs. Actuator deadband affects the variability in the controlled variable. The addition of lag to a control loop (e.g., sensor filtering) results in slower disturbance rejection, which can increase the variability in the controlled variable. Disturbance magnitude directly affects variability. 

Some monitors are prone to drift in their zero point and are affected by external environmental conditions. Thus, they require sophisticated maintenance by skilled personnel or even by the manufacturer. Calibrating a monitor to a known concentration of a target gas is the most accurate method. However, in general it is desirable to have a linear repeatable response over the widest possible gas concentration range. Some sensors require a stabilization period before calibration can be performed following maintenance. This results in a longer overall calibration time. The cost of materials used for calibration is another factor to consider. 

Beyond just being comfortable, wearable sensors must also not create a situation where optimum performance is compromised, particularly in competitive sports. Discomfort itself will naturally lead to less than optimum performance, so the points mentioned in the previous sections are valid here as well. However, in every sport, there could be other factors that need to be considered that do not necessarily lead to discomfort, but can affect performance. For example, a small wearable sensor system can affect drag in sports where it could matter (e.g., swimming) and therefore affect speed without necessarily feeling uncomfortable to wear, obtrusive or heavy. 

The reliability of the data is important in sports performance. The system must always be able to capture the right data, in an accurate and timely manner and with the correct sensitivity. There are various factors to consider that can affect the quality of the data interference and noise caused by motion or micro-environmental conditions, hysteresis, speed of sensor response v/s sport requirement (data lag), loss of contact to the... 

Conventional enzyme electrodes employ disorete-maorosoopio membranes to overcome problems associated with interferences, enzyme immobilization, and electrode fouling. While these types of enzyme electrodes have been commercially developed, there are some limitations with this approach. Some sensors use three relatively thick membranes, resulting in a slow smd complex diffusion path for reactants reaching the enzyme and hydrogen peroxide reaching the electrode. Slow diffusion in this type of system adversely affects the response and recovery time, decreasing sampling rate. Each sensor must be individually constructed, and this construction technique is limited to two-dimensional surfaces. In addition, for sensors that have complex and slow diffusion paths, rates of diffusion must remain constant, otherwise calibration of the biosensor, and more important the maintenance of calibration, are difficult. A variety of factors can influence rates of diffusion, and consequently the performance of the enzyme layer and the performance of the sensor. These complicated, and most often uncharacterizable, properties have made the development of roost biosensors difficult. 

The performance of "classic" DNA sensors is affected by h3d)ridiza-tion efficiency, which depends on a number of factors such as temperature, ionic strength, probe length, and others. However, many of these problems can be minimized by the use of peptide nucleic acids (PNA). PNAs are artificial DNA analogues in which the ribose phosphate ester backbone is replaced by pseudo-peptide backbone (see Scheme 7.3) [52]. 

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