Mechanical movements

The mechanical movements and the data aequisition is controlled by a DEC Alpha-Workstation which is also able to perform the tomographic reconstruction and parts of the visualization of the results. 

Other limitation for the spatial resolution can be found in the detector. A limited number of pixels in the camera array can be a reason for pure resolution in the case of a big field of view. For example, if field of view should be 10 by 10 nun with camera division 512x512 pixels the pixel size will be approximately 20 microns. To improve the relation of the field of view and the spatial resolution a mega-pixel sensor can be used. One more limitation for the spatial resolution is in mechanical movement (rotation) of the object, camera and source. In the case of a mechanical movement all displacements and rotations should be done with accuracy better than the spatial resolution in any tested place of the object. In the case of big-size assemblies and PCB s it is difficult to avoid vibrations, axle play and object non-planarity during testing. 

To reach enough good spatial resolution a new microlaminography approach has been developed. To avoid most errors from mechanical movements we use minimum movable parts (Fig.5). 

In the apphcation of dyes three techniques are used the dye Uquor is moved as the material is held stationary, the textile material is moved without mechanical movement of the Uquor, or both move. 

Transportation of the Textile Material with No Mechanical Movement of the Liquor. Probably the oldest example of dyeing in which the textile alone moves is the ancient box-type skein dye machine in which skeins of yam are hung on wooden pegs with about three-fourths of the skein submerged in the dye Hquor. To prevent stick marks and unlevelness, the sticks are turned by hand at frequent intervals. 

As von Nimitz points out, only cyclic stresses are directly related to failure probability. These stresses are often produced by pulsations in the fluid system, by mechanical vibrations produced by the mechanical movement of certain equipment components, and as a result of the fluid pulsations. Figure 13-8 lists the sequence of events that leads to most failures of equipment and piping. 

A clear understanding of the mechanical movement of machines and their components is an essential part of vibration analysis. This understanding, coupled with the forces applied by the process, are the foundation for diagnostic accuracy. 

Like rotating machinery, the vibration profile generated by reciprocating and/or linear motion machines is the result of mechanical movement and forces generated by the components that are part of the machine. Vibration profiles generated by most reciprocating and/or linear motion machines reflect a combination of rotating and/or linear motion forces. 

Filled needle Sample is taken up into the syringe needle without entering the barrel. Injection is made by placing the syringe needle into the injection zone. No mechanical movement of the plunger is involved and the sample leaves the needle by evaporation. 

Explosive motor. A device in which explosive is completely enclosed and which on operation causes a mechanical movement as of a piston (see p. 195). 

This requirement can be fulfilled by reduction of the electron-acceptor unit(s) or by oxidation of the electron-donor unit(s) by chemical, electrochemical, or photochemical redox processes. In most cases, the CT interaction can be restored by an opposite redox process, which thus promotes a reverse mechanical movement leading to the original structure. 

The mechanical movements taking place in this supramolecular system, in which a free molecule can be driven electrochemically to associate with either of two different receptors, opens the way to futuristic applications in the field of molecular-level signal processors.161 One can conceive second generation systems wherein the electrochemically driven... 

Mechanical movements in supramolecular structures rely on modulation of noncovalent-bonding interactions. Such changes occur when charge-transfer interactions between electron-donor and electron-acceptor groups are weakened. 

The transmitter is the interface between the process and its control system. The job of the transmitter is to convert the sensor signal (millivolts, mechanical movement, pressure diflerential, etc.) into a control signal (4 to 20 mA, for example). 

Both types of Bourdon gauge are most suitable for use with corrosive gases and both can be used most effectively as null-point instruments. Several types of mechanical gauge are available commercially which use electrical capacitance or induction to magnify the mechanical movement of a membrane. Such gauges are easily operated in a differential mode and can be used for measuring pressure differences down to ca. 10 Torr. 

Explosive Actuator, Linear. A self-contained power transmitting device designed to convert chemical energy into controlled mechanical force in the form of linear mechanical movement. It is comprised essentially of a piston, propellant chge, electrical bridge wire and contacts enclosed in a housing (Ref 38b, pp 3-4, Actuator, Explosive, Linear)... 

Firing Pin. In a mechanical fuze, contact sensing is converted directly into mechanical movement of a firing pin which in turn is driven into or against (he first element of an expl train (primer). For the simplest solution to obtain initiation using this method, the forces on munition impact are used to crush its nose, thereby forcing the pin into the primer. In a base fuze, (he pin may float in a guide thru which it moves... 

Cold weather causes the covering to be less resistant to mechanical movement and additional care is required to maintain its reliability. When safety fuse is used in applications where it is closely confined, its burning rate is considerably increased, the tighter the confinement, the faster die burning rate Ref 1) FM-25, Explosives and Demolitions , Department of Army (October 1963)... 

There are many problems, particularly in the field of accounting, for which the small punched-card calculator is suitable. However, for many technical or scientific calculations it is of. only limited utility, primarily because of its limited speed and a basic lack of adaptability to lengthy sequential calculations. The speed limitation comes about principally because the operation of these machines is dependent upon the mechanical movement of cards. Thus, even though electronic calculations may be performed at high speed, this feature cannot be fully exploited. 

The speed of instruction execution can be greatly increased, as it no longer depends upon the mechanical movement of cards. 

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