Specimen rotation axis alignment

To align the specimen rotation axis with the camera center point, two images are recorded at 0° and 180° to take account of any eccentricity of the spindle with respect to the rotational center. The spindle is translated in x until the average of the coordinates of the location a, b or c, d is equal to the pixel value 511.5 at the center of the frame (Fig. 26.53). 

Preferred orientation. If a powder consists of needle- or plate-shaped particles, these tend to become aligned parallel to the specimen axis, and thus certain planes have a greater chance of reflecting the X-rays. To reduce the errors caused by this source, the sample is usually rotated. Alternatively, the sample can be packed into a capillary. 

The Morrison load cycles were applied to selected prostheses in the simulator shown in Figure 1. Cyclic loading patterns were applied in the Tibial Axis and A-P directions, the hydraulic mechanisms being controlled by a waveform synthesiser supplied with some 200 bits of information. The primary joint motion in flexion-extension was achieved by means of a cam driven rack-and-pinion system, while a low-friction self-aligning bearing arrangement on the upper, femoral, specimen holder allowed rotation about the A-P axis. 

Reply bv the Authors The ions in the plasma move randomly within the walls they are confined in therefore, it is not necessary to rotate the specimen. For the specimen configuration of this experiment, however, aligning the axis of the electron beam and the plate surface was effective in nitriding the inner surfaces from the outside edge of the specimen. 

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