Moveable arms

Light source. This provides light for your sample. It s on a moveable arm, so you can swing it out of the way when you place your samples on the prisms. 

Make sure the unit is plugged in. Then turn the on-off switch to ON. The light at the end of the moveable arm should come on. 

Raise the light on the end of the moveable arm so that the light illuminates the upper prism. Get out your dime and, with permission of your instructor, tighten the light source swivel arm lock nut as it gets tired and lets the light drop. 

Figure 7. Schematic of light-scattering devices under micro-gravity conditions a) PROGRA with moveable arm around the dust sample enclosed in a glass vial b) CODAG, with a ring of detectors around the dust, enclosed in a low-pressure chamber where agglomeration takes place.

The whole-body counter is equipped with six sodium iodide doped with thallium (Nal(Tl)) detectors, combined in two triangular arrays. The upper array consists of three detectors that scan above and the lower array of three detectors that scan below the subject. The upper array is on a moveable arm that can be raised from the bed surface to the roof of the counting chamber. The lower array is in a fixed geometry 12 cm below the bed. 

In the on-off device, the sensing element is connected to the spirally wound tube (O) and changes in pressure cause the tube to move such that a lever (P) moves the indicator (L), which indicates the temperature of the system being measured (about 150°F in the figure). Attached to indicator (L) is a contact (A). Placed either side of (L) are moveable arms, (M) and (N), which indicate the minimum and maximum temperature deviation before some corrective action is taken. These two arms are connected to (B) and (C) which also carry electrical contacts. Thus if the temperature drops to 125°F then the contact (A) (on L) makes contact with (B) and presumably results in some form of heat being supplied to the system. On-off systems result in limit cycling, in which the controlled quantity oscillates between the upper and lower limits (many room temperature control systems still work on this principle, and if the upper and lower limit are too far apart one is alternately too hot and then too cold). 

FT-IR utilizes the Michelson interferometer rather than the grating or prism of the dispersive system. The Michelson interferometer has two mutually perpendicular arms. One arm of the interferometer contains a stationary, plane mirror the other arm contains a moveable mirror. Bisecting the two arms is a beamsplitter which splits the source beam into two equal beams. These two light beams travel their respective paths in the arms of the interferometer and are reflected back to the beam splitter and on to the detector. The two reunited beams will interfere constructively or destructively, depending on their path differences and the wavelengths of the light. When the path lengths in the two arms are the same, all of the frequencies... 

The sample holder can turned around in the YZ-plane (the transducers axis being the X-axis) to bring sample after sample into the ultra-sonic beam. The whole sample holder system can be rotated in the XY-plane to change the angle of incidence between 90° for longitudinal wave measurements, to 0° to perform shear wave measurements. Both transducer arms are moveable in the x-direction to change the... 

An additional external heating source was used to solve this problem. Two Osram Xenophot HLX 64 635 (15 Volt, 150 Watt) IR heaters mounted on moveable support arms were used to heat the MS capillary tip, a third one was used to heat the FTIR capillary tip. These three heaters are controlled by one Eurotherm 808 controller with the measuring and the alarm thermocouples mounted near the small ball-joint of the MS heated transfer line/TGA furnace coupling, see Figure 6.6. The measurement of the FTIR/MS capillary tip temperatures was repeated using only these extra heating sources (no TGA furnace switched on), the results are listed in Table 6.2. 

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