Housing accelerometers

Applications over die past several years have included guidance sysLem parts, such as gimbals, gyroscopes, stable platforms, housings, mirrors, aircraft brakes, and accelerometers. In advanced (U.S.) land-based nuclear missiles, there is a precisely machined beryllium sphere, floating, warmed and protected, in a fluid bath. 

Induced microseismic activity was detected using three downhole 4-component detectors and one hydrophone, installed in wells 4550, 4616, 4601 and EPSl in the 1993 experiment. The 4-componet detector consists of accelerometers mounted in a housing and set in sand at the bottom of the borehole. The three 4-component seismic detectors and hydrophone were set at depths of 1,500 m, 1,420 m, 1,600 m and 2,850 m, respectively. 

Acceleration is the time derivative of velocity and the second derivative with respect to time of displacement. Thus, sensors of displacement and velocity can be used to determine acceleration when their signals are appropriately processed. In addition, there are direct sensors of acceleration based on Newton s second law and Hooke s law. The fundamental structure of an accelerometer is shown in Figure 2.3. A known seismic mass is attached to the housing by an elastic element. As the structure is accelerated in the sensitive direction of the elastic element, a force is applied to that element according to Newton s... 

An implanted device also offers a unique opportunity for continuous ambulatory collection and trending of physiologic information. Today s devices can provide a history of the incidence and duration of atrial arrhythmias, track heart rate 24 hours/day, and provide estimates of heart rate variability on a daily basis (Figure 15.8). In addition, many devices are equipped with accelerometers that can be used to estimate and track patient activity [17,18]. Other devices track the impedance between electrodes and the ICD housing as a measure of fluid volume in the chest that can be useful in the management of patients with heart failure [19,20]. The addition of implanted sensors to IGDs promises to olfer new opportunities for providing important clinical information. 

Activity of dogs (Yam et al. 2011) and monkeys (Maim et al. 2004 Papailiou et al. 2008) can be conveniently measured in their home enclosures using an accelerometer placed in a collar or as an integral part of a noninvasive telemetry system. Quantitative video tracking of group-housed cynomolgus monkeys can be achieved using differently coloured jackets (Rose et al. 2012). 

Currently plastics represent around 13% of the total weight of a medium-sized car and industry experts believe that 90% of future car design improvements and innovations will have an electronic content such as electronic tyre pressure monitors installed to improved road safety. The ultimate tyre pressure monitor has been fitted to the world s fastest road car, the Bugatti Veyron 16.4. Its wheel electronics comprise a military grade battery, absolute pressure sensor, temperature sensor, accelerometer micro-controller and radio transmitter/receiver which are housed in a compact wheel housing made from PEEK. 

Accelerometers attached to the housing measured x h, Yh with x, yh obtained by double numerical integration. The journal displacements with respect to a fixed position in space were obtained from ... 

---