Push-pull driving forces

The interaction of regulative driving forces (regulative push and pull) as well as the importance of the (limited) official execution can be substantiated well using the case studies ... 

In enzymes, the active site may possess acid and base groups intimately associated with the conjugate base and acid functions, respectively, of the complexed substrate the push-pull mechanism is possible but might not be a driving force. The halogenation of acetone in the presence of aqueous solutions of carboxylic acid buffers exhibits the rate law of Equation 11.2 where the third-order term, although small, has been shown to be significant and due to bifunctional concerted acid-base catalysis (Scheme 11.13) ... 

The invention that positioned osmosis as a major driving force for controlled drug delivery was the elementary osmotic delivery system. ALZA has developed elementary osmotic delivery systems under the name OROS. A successful modification that overcame the disadvantages of the elementary osmotic pump was the Push-Pull osmotic drug delivery system. The following sections are devoted to the principal features of these systems. 

Refer to the portion of Figure 4.6 where the source tank fluid level is below the center line of the impeller in either the system connected in parallel or in the system connected in series. At the surface of the wet well (point 1), the pressure acting on the liquid is equal to the atmospheric pressure Patm minus the vapor pressure of the liquid Py. This pressure is, thus, the atmospheric pressure corrected for the vapor pressure and is the pressure pushing on the liquid surface. Imagine the suction pipe devoid of liquid if this is the case, then this pressure will push the fluid up the suction pipe. This is actually what happens as soon as the impeller starts moving and pulling the liquid up. As soon as a space is evacuated by the impeller in the suction pipe, liquid rushes up to flU the void this is not possible, however, without a positive NPSH to push the liquid. Note that before the impeller can do its job, the fluid must, first, reach it. Thus, the need for a driving force at the inlet side. 

The second type has two rails, one is the power rail and the other is the free rail. The former is the rail exerting the pushing/pulling force for moving the load the latter supports the weight of the trolley, but it has no driving force. This system... 

The amplitude of the laser-cooled ion is enhanced resonantly near o)+ and 0) with maxima shifted from co+ and co by an amount that increases with y,. The resonance width is approximately y,. The in-phase amplitude has a dispersive shape, as for identical ions, and when only the laser-cooled ion is subject to a driving force (excitation by laser modulation) the amplitude has a zero-crossing at C0+ and co. For electrode excitation, where both ions are driven, the zero-crossing is offset from co+ or co by an amount that, for yi/co+ 1 is of the order of (yi/co+J. Intuitively, such an offset is present because, when both ions are driven, the driven motion of the non-cooled ion perturbs the phase of the laser-cooled ion. In contrast, when only one ion is driven, the other ion is pulled or pushed into phase with the driven ion. 

The development of new nonwoven filters is from both pull (customer demand) and push (technology advancement) aspects. On one hand, concerns about the environmental impact and human health are the two major demand-driving forces for pushing the filter and filtration industry to grow steadily and rapidly. Environmental concerns, including the requirements of eliniinating air and water pollution from, for example. 

Electrostatic speaker and earphone did not become popular because they need special driving circuits for the capacitive load. The equivalent circuits for the electret-based device and the device with external bias are the same, but the electromechanical force factor is different. For the electret speakers, the induced charge becomes unstable for a large gap as can be seen in microphones. Based on optimization studies of the acoustic parameters from an equivalent-circuit analysis, nonlinear distortion in a push-pull structure derived from a single-ended structure... 

Within the sulfur world, there is a notable example of pure market pull the replacement of elemental sulfur by pyrites after the TAC incident. An unprecedented feature was the speed of the entire process, from the technical development to its penetration into a global industry. The stage had been perfectly set. The new technology was fairly easy to develop and implement. The special feature was that the customers detested the current supplier. The sulfur world had more than its fair share of these market-pull technology advances the Frasch process is another notable example. That is not to say that sulfur scientists are more market oriented than others. Quite the opposite, the driving force has often been the poor performance of the sulfur industry, which creates these rare maiket-pull opportunities. Instead of being labeled market-pull situations, fundamentally they should more properly be tagged supplier push ... 

An electrochemical cell, such as the Daniell cell, operates by the oxidation reaction producing electrons in the zinc anode, which are then pulled round the external circuit (wires, bulbs, voltmeter, etc.) by the reduction reaction at the copper cathode. As long as the overall reaction is not at equilibrium, the oxidation reaction pushes electrons into the external circuit, and the reduction reaction pulls them out. The cell is described as doing work since it produces a force that moves electrons around the external circuit. This work can light a bulb, drive an electric motor, etc. 

Another novelty is the abrasion resistant material composition option that confers much improve abrasion resistance and somewhat lower coefficient of friction. The mechanical drive tape will also transfer tension and compressive forces when used in non-linear directions. Contributing factors are not only the tape s axial stiffness, providing the push and pull, but also its torsional and edge-bend flexibility. 

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