Compressed air gives flame thrower long range
- Book ID
- 103077721
- Publisher
- Elsevier Science
- Year
- 1945
- Tongue
- English
- Weight
- 74 KB
- Volume
- 240
- Category
- Article
- ISSN
- 0016-0032
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✦ Synopsis
CURRENT TOPICS. 67 new phototimer, according to Henry D. Moreland, manager of engineering of the Westinghouse X-Ray Division, automatically assures a correct x-ray expo-. sure, enabling the technician not only to double the number of exposures formerly made but to achieve better and more useftfl results as well. "In order to evaluate accurately x-ray pictures," Mr. Moreland said, "it is important that the exposures be uniform in density and in what photographers call 'contrast'--the sharpness of difference between the light and the dark areas."
X-rayed objects may vary not only in size and thickness but even in the degree to which x-rays are transmitted. These variables make it difficult to obtain uniform film exposures. Expert technicians develop considerable skill in estimating x-ray penetration, but such evaluations and measurements are time-consuming and at best are only approximations. Therefore even the best technician Can only attain comparative uniformity of film exposures. "The procedure is much like that used by a photographer who has no exposure meter," Mr. Moreland pointed out. "He must use his past experience to judge the proper setting of his camera to take into account light intensity, shutter speed, and diaphragm opening. The new Westinghouse Phototimer is a device to turn the speed and accurate perception of electronics to this task." R. H. O.