Search results
Results from the WOW.Com Content Network
Cosmic ray visual phenomena, or light flashes (LF), also known as Astronaut's Eye, are spontaneous flashes of light visually perceived by some astronauts outside the magnetosphere of the Earth, such as during the Apollo program.
Chamberlain, LiftMaster, and Craftsman have interchangeable parts, primarily the gear and circuit boards. The greatest difference between the brands is that Chamberlain and Craftsman operate on a square shaped split-rail system, while LiftMaster consists of one single solid piece of inverted t-shaped rail.
Video demonstration of high-speed flash photography. A flash is a device used in photography that produces a brief burst of light (lasting around 1 ⁄ 200 of a second) at a color temperature of about 5500 K [1] [citation needed] to help illuminate a scene. The main purpose of a flash is to illuminate a dark scene.
The senders had to determine if there was a need to rotate the falling blocks, but without the ability to rotate them – only the receiver was able to perform this operation. At the edges of each screen, were two icons with two flashing lights in two different frequencies, (one at 15 Hz and the other at 17 Hz).
The shape properties of the light waveform (e.g. sinusoidal, rectangular pulse and its duty cycle); see Figure 1; The average light level of the light source and its contrast with the background light level within the environment; The viewing angle and changes in direction of view by the observer; Physiological factors such as age and fatigue.
The flicker of a CRT monitor can cause various symptoms in those sensitive to it such as eye strain, headaches [9] in migraine sufferers, and seizures in epileptics. [10]As the flicker is most clearly seen at the edge of our vision there is no obvious risk in using a CRT, but prolonged use can cause a sort of retinal shock where the flickering is seen even when looking away from the monitor.
Flicker vertigo, sometimes called the Bucha effect, is "an imbalance in brain-cell activity caused by exposure to low-frequency flickering (or flashing) of a relatively bright light." [ 1 ] It is a disorientation -, vertigo -, and nausea -inducing effect of a strobe light flashing at 1 Hz to 20 Hz, approximately the frequency of human brainwaves .
Headlight flashing might have come into more common use as a means of attempting driver-to-driver communication by the mid-1970s, [3] when cars began to come with headlight beam selectors located on the steering column—typically activated by pulling the turn signal stalk—rather than the previous foot-operated pushbutton switches.