We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
June, 1930] ABSTRACTS 703
time in a "dead" room, that is, one in which the average coefficient of absorption was of the order of 0.5, gave values lower than those computed by the formula. For such a case the author maintains that the assumptions of homogeneous distribution and random direction do not hold and that the absorption is not a continuous process but is more properly considered as taking place in a finite number of discrete steps, with an intervening time interval of At = p/v, where v is the velocity of sound and p is the mean free path of a sound element between reflections. From these assumptions he derives the equation
0.05 V
-Sloge (1 da]
where 5 is the total area of the room and aa is the average absorption coefficient.
This equation gives results which agree more closely with the experimental results in "dead" rooms. In more reverberant rooms the two formulas give practically the same values. The author points out the importance of the new point of view in the talking picture industry where conditions of high absorption are frequently desired in sound stages. P. E. S.
High Speed Camera. Science ind. phot., No. 4, April, 1930, p. 160. The Institute for Physical Research of the University of Tokyo has shown, during the recent Scientific Congress in Tokyo, a camera taking 40,000 pictures a second, by means of a drum having 180 mirrors revolving at a speed of 225 revolutions a second. G. L. C.
Film Container Reel. R. C. HOLSLAG. Movie Makers, 5, February, 1930, p. 123. A combined reel and humidifying can is described which consists of a flange that clips over the circumference of an unperforated reel. A new projector stand is also described which holds the projector, film splicer, spare reels, rewind, and translucent screen. — Kodak Abstr. Bull.
Special Carbon Arc for Wide Films. Mot. Pict. News, 41, Feb. 1, 1930, p. 69. A special carbon arc, claimed to have from 30 to 50 per cent greater brilliancy than the sun affords, is now being marketed. — Kodak Abstr. Bull.
Novel Projector Shutter. Bioscope (Mod. Cinema Technique), 81, Dec. 18, 1929, p. v. The new Berger projector shutter, recently marketed by the Globe Reliance Corporation of America, is said to pass 50 per cent more light than any previous design. The shutter consists of three rotating members, each with three blades. The shutters are so stepped that the blades pass behind each other, and the actual gate shutter is formed in the central portion, so that at any one moment the shutter consists of one edge of a blade from each of the rotating members. —Kodak Abstr. Bull.
Philips Incandescent Projector Lamp. T. J. J. A. MANDHRS. Cinemat. /rang., 12, Dec. 21, 1929, p. 103. Bioscope (Mod. Cinema Technique), 82, Feb. 12, 1930, p. Hi. Kinotechnik, 11, Sept. 5, 1929, p. 468. The Philips projection lamp avoids loss of light by absorption caused by blackening of the lamp walls. The upper part of the bulb is spherical, the lower part narrowing to a cylinder, near the bottom of which is the filament. The leads enter at the top. Convection currents within the bulb carry the tungsten vapor from the filament to the upper part of the bulb, where it deposits. The loss in efficiency throughout the life of the lamp is very small. — Kodak Abstr. Bull.