Force control

Jarvis S P, Yamamoto S-l, Yamada H, Tokumoto H and Pethica J B 1997 Tip-surface interactions studied using a force controlled atomic force microscope in ultrahigh vacuum Appl. Phys. Lett. 70 2238... 

Fig. 9. (a) Depth-sensing nanoindenter model and (b) simple mechanical model for force controlled indentation assuming purely elastic contact mechanics. 

Road wear is force controlled. This is a fundamental difference to slip-controlled laboratory abrasion test machines or wear tests with a trailer as described above. In force-controlled events the abrasion loss is inversely proportional to the stiffness of the tire whilst under slip control the abrasion is proportional to its stiffness (see Equations 26.18a and 26.19a). 

Jarvis and Pethica [51] also investigated adhesion as a function of surface wettability but used a diamond tip for its known hydrophobic properties. They also used magnetic force-controlled AFM and applied forces to magnetic material behind the tip to bring the... 

There are two important underlying ideas that we shall return to throughout this work. Firstly, we should be aware that intermolecular forces control the way in which materials behave. This is where the... 

At the conclusion of the first falling rate period it may be assumed that the surface is dry and that the plane of separation has moved into the solid. In this case, evaporation takes place from within the solid and the vapour reaches the surface by molecular diffusion through the material. The forces controlling the vapour diffusion determine the final rate of drying, and these are largely independent of the conditions outside the material. 

To take the anology further disturbance in the market force-control causes problems in national economies and so it does in the biochemical economy in muscle. For example, if the rate of ATP expenditure exceeds the capacity for generation of ATP, fatigue rapidly results. In many people, this leads to ill health it is a major factor limiting their daily activities and, therefore, their well-being... 

An important observation regarding the equations representing the deformation is that the shape of the deformation (with only vertical scaling factors) is independent of the material constants and only dependent on the area of force application. The deformation shape is therefore similar for different material properties. The material properties and applied force control only the actual amount of the deformation. This is ideal for our initial goal that was to determine the typical deformation profile of the polish pad. All that remains is the determination of the appropriate length scale to use to represent the deformation. 

Rate of interaction-force-controlled interparticle collision... 

The force controls the remarkably persistent coherence in products, a feature that was unexpected, especially in view of the fact that all trajectory calculations are normally averaged (by Monte Carlo methods) without such coherences. Only recently has theory addressed this point and emphasized the importance of the transverse force, that is, the degree of anharmonicity perpendicular to the reaction coordinate. The same type of coherence along the reaction coordinate, first observed in 1987 by our group, was found for reactions in solutions, in clusters, and in solids, offering a new opportunity for examining solvent effects on reaction dynamics in the transition-state region. 

Intramolecular reactions are obliged to obey the powerful rules that govern which cycloadditions are allowed and which forbidden, but they can override the weaker forces controlling regio- and stereoselectivity, and it is important to remember this opportunity for synthetic design, when the trends outlined above are in conflict with the aims of the synthesis. 

In gas-solid flows, flow patterns of both phases depend not only on the initial conditions and physical boundaries of the system but also on the mechanisms of momentum transfer or the interacting forces between the phases. The forces controlling the motions of particles may be classified into three groups (1) forces through the interface between fluid and particles, (2) forces due to the interactions between particles, and (3) forces imposed by external fields. Although interparticle forces and field forces do not directly change the course of the fluid motion, they may indirectly influence the motion via particle-fluid interactions. 

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