Effort actuation

Fig, 5.2 Bond graph model (a) acausal (b) effort (torque) actuation (c) flow (velocity) actuation and (d) approximate effort actuation... 

As indicated in Fig. 5.2b, effort actuation leads to all four dynamic components (Iji. IJ2, C ki and C k2) having integral causality. However, the effect of the effort source is to break the system into two subsystems which, apart from sharing an input, are completely separate. It follows that using effort actuation the system is uncontrollable moreover, as the uncontrollable part is also unstable, the system is unstabilisable. 

Figure 5.3a shows the result of applying this recipe to the system with effort actuation (when dualised, the effort source Se so becomes the flow source Sf so) one component (C ki) is in integral causality and so it is confirmed that this system is not structurally controllable with effort actuation. Conversely, Fig. 5.3b shows the result of applying this recipe to the system with flow actuation no component remains in integral causality and so it is confirmed that this system is structurally controllable with effort actuation. 

Fig. 5.3 Maximising derivative causality (a) dual effort actuation and (b) dual flow actuation...

There have been some efforts over the past three decades to develop positive development vane motors and reciprocating motors for operation with drilling mud as the actuating fluid. These efforts have not been successful. 

It is only yesterday that we heard of a discovery by Sir William Ramsay and other scientists—working, I believe, independently— which may mean the transmutation of one chemical element into another—subject, of course, to the validity of Prof. Sir J. J. Thomson s alternative contention. We must seek to know more of the trend of recent discovery in this direction, and we need to be informed by someone who has an eye to the efforts of the past, but also a complete disregard of any a priori reasonings which actuated those efforts. 

The use of sensors for surveillance of industrial combustion processes is state of the art. Especially optical sensors detect the existence of a flame. With decreasing furnace performance the amount of installed sensors declines. In residential appliances there are nearly no sensors installed because the costs for both, sensors and actuators, have to be balanced with the technical profit. The efforts for setting up combustion controls are very ambitious but in many cases not successful. First a distinction has to be made between sealed boilers and those that are open towards the room in which they are installed. The resulting controls cannot be interchanged between these two groups of appliances. 

Levels 4 and 5 clearly affect the process economics, as both levels are directed to optimizing the process in some manner. In contrast, levels 1, 2, and 3 would appear to have no effect on process economics. Their direct effect is indeed minimal, although indirectly they can have a major effect. Basically these levels provide the foundation for all higher levels. A process cannot be optimized until it can be operated consistently at the prescribed targets. Thus, satisfactory regulatory control must be the first goal of any automation effort. In turn, the measurements and actuators provide the process interface for regulatory control. 

These devices permit the drug to be delivered to the airways as a dry powder aerosol. All currently available DPIs are breath-actuated, thus the respirable cloud is produced in response to the patient s effort. DPIs therefore have the following advantages over pMDIs ... 

Since the appearance of the redox [ii, iii] and conducting [iv] polymer-modified electrodes much effort has been made concerning the development and characterization of electrodes modified with electroactive polymeric materials, as well as their application in various fields such as -> sensors, actuators, ion exchangers, -> batteries, -> supercapacitors, -> photovoltaic devices, -> corrosion protection, -> electrocatalysis, -> elec-trochromic devices, electroluminescent devices (- electroluminescence) [i, v-viii]. See also -> electrochemically stimulated conformational relaxation (ESCR) model, and -> surface-modified electrodes. 

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