Sensors and transducers

The model immunoassay is the enzyme-linked immunosorbent assay (ELISA) in which a non-specific capture antibody is bound to a surface, such as a multi-well plate or small tube [13]. In the basic form of ELISA, a second antibody tagged with an enzyme interacts specifically with the analyte. The enzyme assay produces a colored product that is read with a spectrophotometer. There are many variations on the basic immunoassay format that serve to increase sensitivity, specificity, linear range, and speed. Many commercial instruments have been developed to take advantage of various technologies for reporter molecules. The immunoassay may be coupled to an electronic sensor and transducer, such as a surface acoustical wave (SAW) sensor. Electrochemiluminescence (ECL) is a method in which the detector antibody is tagged with a ruthenium-containing chelate [13-15]. When the tag is... 

M. Aslam, I. Taber. M. A. Tamor, T. J. Potter, and R. C. Elder, Transducers, Proceedings of the International Conference on Solid-State Sensors and Transducers, Yokohama, Japan, June 7-10, 1993. 

A dedicated acquisition system able to monitor and register the voltages of the individual cells during the different runs is adopted. Moreover a d-space board is used for the acquisition and control of all signals associated with the FCS system components (valves, sensors, and transducers). 

Mamishev A, Rajan KS, Yang F, Du Y, Zahn M (2004) Interdigital sensors and transducers. Proc IEEE 92 808-945... 

The IRRAS method can be used to obtain information about ultrathin films not only at metals but also on semiconductor and dielectric (including liquid) substrates. This class of problem is applicable to many areas, including thin-fihn optics, electronic and electroluminescent devices [27] (Chapter 5), sensors and transducers [28], flotation technology [29] (Section 7.4.4), and biomedical problems [30, 31]. Although the sensitivity is much lower than when metallic substrates are used, the waiving of the metal selection rule allows both s- and /7-polarized spectra to be measured and thus a more thorough investigation of molecular orientation within the layer. 

Intelligent packaging Smart labels Medical electronics Electronic manufacturing Defence and aerospace Sensors and transducers... 

Despite the considerable development of new sensors and transducers for various chemical substances in recent years, the measurement of physical parameters such as temperature, pressure, density, flow rate, humidity, and refractive index are still very important aspects of industrial process analysis. Some of the... 

Automation of the process, as described above, requires the identification of a set series of actions to be carried out by industrial robots. In turn, this requires the appropriate industrial robots be designed and constructed in such a way that the actual physical movements necessary for the task can be carried out. Each robot will incorporate a number of servomechanisms that drive the specific movements of parts of the robot according to the control instruction set. They will also incorporate any number of sensors and transducers that will provide input signal information for the self-regulation of the automated process. This input data may be delivered to the control program and compared to specified standards before it is fed back into the process, or it may be delivered directly into the process for immediate use. 

Many types of sensors and transducers have particular signal conditioning requirements. For example, thermocouples require cold-junction compensation for the thermoelectric voltages created where the thermocouple wires are connected to the data acquisition equipment. Resistive temperature devices (RTDs) require an accurate current excitation source to convert their small changes in electrical resistance into measurable changes in voltage. To avoid errors caused by the resistance in the lead wires, RTDs are often used in a 4-wire configuration. The 4-wire RTD measurement avoids lead resistance errors because two additional leads carry current to the RTD device, so that current does not flow in the sense, or... 

Self-assembled monolayers of surfactant molecules constitute model systems that permit incorporation of diverse chemical and physical properties and ease of preparation. Technological areas involving electronic and optical devices, sensors and transducers, protective and lubricating layers, and pattemable materials require ultrathin organic molecular films in which the relationships between structure, forces, and electrical and mechanical properties are continuously under investigation according to their application." ... 

This chapter presents a brief overview on sensor and transducer applications of piezoelectric and electrostrictive polymers. Piezoelectric and electrostrictive polymers are smart electromechanical materials which have already found commercial applications in various transducer configurations. Novel applications may arise in the emerging fields of autonomous robots, electronic skin, and flexible energy generators. This chapter focuses on recent device demonstrations of piezoelectric and electrostrictive polymers in these novel fields of research to stimulate and to facilitate the exchange of ideas between disciplines. The applications considered include piezoelectric sensors for electronic skin, piezoelectric loudspeakers and transducers for mechanically flexible energy harvesters, as well as electrostrictive transducers for haptic feedback in displays. 

Patranabis, D., 2003. Sensors and Transducers, second ed. Prentice-Hall, New Delhi. 

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