Integrated transducers

Yaralioglu, G.G., Wygant, I.O., Marentis, T.C., Khuri-Yakub, B.T., Ultrasonic mixing in microfluidic channels using integrated transducers. Anal. Chem. 2004, 76, 3694-3698. 

The grey zone in this figure represents the volume of activated carbon at the bottom of the bed. During adsorption, the temperature in this zone will increase at a rapid rate as exothermic adsorption occurs. As sites are filled with solvent molecules and the adsorbent rate declines, so also does the rate of temperature increase. Completion of the bed s use may be recognized by comparing the response of the temperature sensor in the bottom bed volume to a fixed reference value over time, or by use of an integrating transducer to continuously calculate the rate of temperature change with time and compare that to another fixed reference value. 

The arrangement of the composite sample with integrated piezoelectric transducer represents a bending bar. If this sample is deformed by a vertically applied force F, the integrated transducer is deformed, thus producing charges on the surface due to the piezoelectric effect. This in turn influences charges on two electrodes, positioned on the upper and lower side of the transducer. 

Ocean-Bottom Seismometer, Fig. 4 Example of release units. Left-, motor-driven release unit with integrated transducer (Photograph M. Schmidt-Aursch, Bre-merhaven). Right, bum wire mechanism (Photograph courtesy of A. Ndiaye, INSU, Paris)... 

Under ideal conditions (e.g., point sources producing spherical waves and no multiple reflections) a rectified backscattered signal represents line integrals of the ultrasonic reflectivity over concentric arcs centered at the transducer position. To reconstruct the reflection tomo-... 

Piezoresistive Sensors. The distinction between strain-gauge sensors and pie2oresistive (integrated-circuit) sensors is minor. Both function by measuring the strain on an elastic element as it is subjected to pressure. A pie2oresistive transducer is a variation of the strain gauge that uses bonded... 

Since acceleration is the second derivative of displacement, a piezoelectric accelerometer sensor with an integrator becomes a velocity transducer. This arrangement is gradually superseding the self-generating mo ing-coil velocity sensor (where a coil of wire moves relative to a magnetic field). 

To circumvent this problem, vectors that are based on lentiviruses have been developed. In contrast to prototypic retroviruses, lentiviruses do not require cell division for integration. Gene-therapy vectors have been developed from a broad spectrum of lentiviruses including human immunodeficiency vims (HIV), simian and feline immunodeficiency vims as well as visna/maedi vims. The most widely used lentiviral vector system is based on HIV-1. These vectors can efficiently transduce a broad spectrum of dividing and nondividing cells including neurons, hepatocytes, muscle cells, and hematopoietic stem cells [1,2]. 

The development of leukemia in patients receiving retrovirally transduced cells, clearly underlines that insertional mutagenesis is a major concern for integrating vectors. 

The MIMOS II Mossbauer spectrometer sensor head (see Sect. 3.3) is located at the end of the /nstrument Deployment Device IDD (see Fig. 8.27) On Mars-Express Beagle-2, an European Space Agency (ESA) mission in 2003, the sensor head was also mounted on a robotic arm integrated to the Position Adjustable Workbench (PAW) instrument assembly [344, 345]. The sensor head shown in Figs. 8.28 and 8.29 carries the electromechanical transducer with the main and reference Co/Rh sources and detectors, a contact plate, and sensor. The contact plate and sensor are used in conjunction with the IDD to apply a small preload when it places the sensor head, holding it firmly against the target. 

Mechanical rheometry requires a measurement of both stress and strain (or strain rate) and is thus usually performed in a simple rotating geometry configuration. Typical examples are the cone-and-plate and cylindrical Couette devices [1,14]. In stress-controlled rheometric measurements one applies a known stress and measures the deformational response of the material. In strain-controlled rheometry one applies a deformation flow and measures the stress. Stress-controlled rheometry requires the use of specialized torque transducers in conjunction with low friction air-bearing drive in which the control of torque and the measurement of strain is integrated. By contrast, strain-controlled rheometry is generally performed with a motor drive to rotate one surface of the cell and a separate torque transducer to measure the resultant torque on the other surface. 

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