Force shunt

If the sensor bore does not correspond to the required tolerances, the sensor front touches the sensor bore in many cases, and the sensor loses its sensitivity. In technical language, this effect is called force shunt and can cause measurement errors of up to 30%. For this reason, cavity pressure sensors have recently developed that are initially built precisely into a sleeve and then calibrated in a second step [1]. The actual sensor is thus protected during installation, and measurement errors through the installation are excluded (PRIASAFE principle). The determined sensitivity is eventually stored in the sensor body itself as a code, so that no adjustments in the subsequent electronics in the industrial use have to be made [2]. The optimal measuring ranges are determined automatically as soon as the sensor is connected to the electronics (PRIASED principle). 

Figure 5.12 describes the advantages of this principle. Standard cavity pressure sensors are shown in the top row where the first one is installed correctly (left) and the second one touches the sensor bore due to an inclined installation (right). As a consequence, the second sensor loses sensitivity (force shunt). This is reflected in the measured values, which are too low (shown schematically by the two internal pressure curves). The so-called PRIASAFE sensors, which are protected by a sleeve, are shown in the lower row. Both the correctly installed sensor (left), as well as the sensor with the sleeve touching the sensor bore (right), provide identical, problem-free measurement signals. This principle considerably facilitates the handling of cavity pressure sensors. 

Both vasoconstrictors and vasodilators have been used in the treatment of priapism. Vasoconstrictors are thought to work by forcing blood out of the cavernosum and into the venous return. Aspiration of the penile blood followed by intracavenous irrigation with epinephrine (1 1,000,000 solution) has been effective with minimal complications.37 In severe cases, surgical intervention to place penile shunts has been used, but there is a high failure rate, and the risk of complications, from skin sloughing to fistulas, limits its use. 

This set of experiments has focused on the use of two nondestructive electrochemical techniques to measure polarization resistance and thereby estimate the corrosion rate. In addition, the effects of scan rate and uncompensated ohmic resistance were studied. Three main points should have been made by this lab (1) Uncompensated ohmic resistance is always present and must be measured and taken into account before Rp values can be converted into corrosion rates, otherwise an overestimation of Rv will result. This overestimate of Rp leads to an underestimate of corrosion rate, with the severity of this effect dependent upon the ratio Rp/Ra. (2) Finite scan rates result in current shunted through the interfacial capacitance, thereby decreasing the observed impedance and overestimating the corrosion rate. (3) Both of these errors can be taken into account by measuring Ra via EIS or current interruption and by using a low enough scan rate as indicated by an EIS measurement in order to force the interfacial capacitance to take on very large impedance values in comparison to Rp. 

The transformation of the lobular architecture is initiated and maintained by at least two histomorphological processes (i.) piecemeal necrosis and (2.) bridging necrosis, which provides string-like links between the central veins and the portal fields. Portocentral shunts, which are of significance for the fate of cirrhosis, make use of these bridges as routes for their development. During the course of time, these channels, which acquire solid basal membranes like capillaries, carry the portal blood directly to the venous flow-off. As a result, blood is withdrawn from the respective acini these areas become more susceptible to disruption and damage and are forced to restructure anew, (see chapter 35)... 

One can consider that plankton have regulatory means by which copper at moderate concentrations is shunted mainly to the copper requiring systems and does not interfere with copper sensitive systems. At higher levels, a rejection mechanism presumably operates. At toxic levels of copper, this mechanism can no longer keep up with the input of metal due to the large external driving force. 

Not much more is known about the expeditiousness which, in this context, may be defined as the rate at which the protonmotive force rises after the onset of the pump, but some general predictions can be made. The expeditiousness is the higher the fester the pumping rate of protons is relative to the conductance of passive ions, which tend to shunt the electrogenic pump effect, in other words, to maintain electroneutrality. We see that the two components of the protonmotive force, the electrical and the chemical PD, are controlled by different factors and may therefore develop at different rates, as is illustrated by the following two extreme conditions ... 

On the other hand, if the passive conductance is very high, it will keep electrical effects small but allow instead an equivalent rise of the chemical PD of protons. This rise will depend on the buffer capacity of the medium, which is normally much higher than the e lectrical capacity. From its value In the mitochondria we would estimate that about a million protons have to be expelled per 1 mvolt rise of the chemical PD, and hence of the protonmotive force. Obviously, the rise in chemical PD in this case is thousand or more times slower than the electrogenic one in the former case. At the rate assumed for the mitochondrial proton pump, we would predict that the critical protonmotive force, i. e. about 200 mvolts, could be reached within a few hundred milliseconds in the first case, but would take a few himdred seconds in the last case. It follows that the expeditiousness of the coupling, i.e. the speed at which this critical protonmotive force is reached after the initiation of the pump depends rai the relative contribution of the initial pumping rate relative to the shunting pathways for passive ions. 

Choosing a thickness-polarized, thickness-vibrating piezoelectric element as an example, we can define the applied voltage V current i dimensions b, h, and / and the output force and velocity F and u the cross-sectional area bounded by b and I can be defined by A here it is assumed this area is electroded on the top and bottom faces of the element and that b and / are much greater than h. Treating it as a collection of discrete circuit elements as shown in Fig. lb, the Van Dyke circuit allows the analysis of one resonance within the isolated element. Most piezoelectric materials are capacitive insulators, and the shunt capacitance Cs = is the constant capac-... 

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