Gamma wave

Alpha, Beta and Gamma waves. Each of them has a specific frequency and amplitude. Typical samples of human EEG signals are shown in Fig. 11.3. The Delta wave is the largest wave with amplitude between 20 and 200 pV, but has the lowest occurring fi-e-quency at less than 4 Hz. The amplitude of the Theta wave is between 20 and 1(X) pV and its frequency between 4 and 7 Hz. The Alpha wave is the most commonly recorded wave, at a frequency between 8 and 13 Hz and amplitude at about 20—60 pV. The Beta wave is relatively faster, occurring at 14—30 Hz frequency with amplitude at around 2—20 pV. Finally, the Gamma wave is the smallest and fastest wave, which occurs over 30 Hz, and its amplitude is between 5 and 10 pV. 

A problem with the early MWD mud pulse systems was the very slow rate of data transmission. Several minutes were needed to transmit one set of directional data. Anadrill working with a Mobil patent [100] developed in the early 1980s a continuous wave system with a much faster data rate. It became possible to transmit many more drilling data, and also to transmit logging data making LWD possible. Today, as many as 16 parameters can be transmitted in 16 s. The dream of the early pioneers has been more than fulfilled since azimuth, inclination, tool face, downhole weight-on-bit, downhole torque, shocks, caliper, resistivity, gamma ray, neutron, density, Pe, sonic and more can be transmitted in realtime to the rig floor and the main office. 

Retrievable Tools. Retrievable MWD tools similar to the steering tools are available from several service companies. They are generally battery powered and generate coded positive pressure mud pulses or continuous pressure waves. The lower part of the tool has a mule shoe that engages in a sub for orientation. Currently, tools are available for measuring directional parameters and gamma rays. A typical retrievable tool is shown in Figure 4-251. 

Figure 12.10 The electromagnetic spectrum covers a continuous range of wavelengths and frequencies, from radio waves at the low-frequency end to gamma (y) rays at the high-frequency end. The familiar visible region accounts for only a small portion near the middle of the spectrum.

Godschalk M, Dzoljic M, Bonta I Slow wave sleep and a state resembling absence epilepsy induced in the rat by gamma-hydroxybutyrate. Eur J Pharmacol 44 103-111, 1977... 

Scrima L, Hartman PG, Johnson EH, et al The effects of gamma-hydroxybutyrate on the sleep of narcolepsy patients a double blind study. Sleep 13 479 90, 1990 Series F, Series 1, Cormier Y Effects of enhancing slow-wave sleep by gamma-hydroxybutyrate on obstructive sleep apnea. Am Rev Respir Dis 143 1378-1383, 1992 Shannon M Methylenedioxymethamphetamine (MDMA, ecstasy ). Pediatr Emerg Care 16 377-380, 2000... 

Radiant Energy—The energy of electromagnetic radiation, such as radio waves, visible light, x and gamma rays. 

The other plots are made with the software TABLECURVE. The special function F2 used there is a log-normal relation and F3 is a sine-wave function. Usually a ratio of low degree polynomials also provides a good fit to bell-shaped curves here five constants are needed. The Gamma distribution needs only one constant, but the fit is not as good as some of the other curves. The peak, especially, is missed. 

Radiation (ionizing) Alpha particles, beta particles, gamma rays, x-rays, and other particles capable of producing ions does not include nonionizing radiation forms such as radio waves, microwaves, or visible, infrared, or ultraviolet light. 

Gamma X-rays Ultraviolet Infrared Microwave Radio and TV Waves... 

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