Sound Producers

Continuous, coarse, whistling sound produced in the respiratory airways during breathing when air flow becomes accelerated through narrowed or obstructed airways. 

Lack of diversity of outlets for example, when the supermarket is the co-op s only customer then the group has been left with a lot of waste products which the supermarket has rejected because their specification demands product excellence and uniformity. It is therefore important to find other outlets for perfectly sound produce that has been graded out by the supermarket packer. Other markets include restaurants, shops, wholesalers and consumer groups. 

More recently, explosives have been tested for impact sensitivity by an impact machine in which 40 mg of explosive on sandpaper are placed between an anvil and a steel cylinder. A 2.5 kg weight is dropped from different heights and the sound produced serves to indicate a go or no go . The result from 25 drops is calculated to give a height at which the probability of explosion is 50%. Results from a compilation104 are presented in Table 12 and show that the relative values of TNT and picric acid are reversed from the previous table. TNT is relatively more sensitive on the Type 12 impact machine than in the FI impact test. TATB is so insensitive that it fails to explode at the maximum drop height of the machine. 

As common observation tells us, in nature we have devices that produce, in finite time and finite space, waves with a fairly well-defined frequency. For instance, when the hammer strikes the piano chord, a wave of fairly well-defined frequency is produced. Furthermore, this real physical sound wave has, as we very well know, a beginning and also an end. So why not describe this sound, produced by the piano, by a wave, with a beginning and an end, a finite wave, with a well-defined frequency. For what physical reason one has to say... 

Gun-cotton is considerably heavier than unprepared cotton, and may be distinguished therefrom by its harshness, and by tbe crepitating sound produced when pressed by the hand. When well made, there is scarcely any change in color or general appearance. It may also be known from common cotton by its electric condition for if a portion be pulled briskly between the finger and thumb of a dry hand, the fibres will adhere with great tenacity. If a strip of prepared paper ho thus treated, it will, on presenting one end to tho knuckle, be alternately attracted and repelled, and thus pait with its electricity. Gun-eottou Is also perfectly soluble in ether, and if the solution be poured on the surface of oold water, the xyloidin yields an opaque film thereon, which, when collected and dried, forms a remarkably explosive paper,... 

The acrosomal process of some invertebrate sperm cells is an actin cable that sometimes forms almost instantaneously by polymerization of the actin monomers and shoots out to penetrate the outer layers of the egg during fertilization (Chapter 32). The stereocilia, the "hairs" of the hair cells in the inner ear, contain bundles of actin filaments.302 Motion of the stereocilia caused by sound produces changes in the membrane potential of the cells initiating a nerve impulse. In certain lizards each hair cell contains about 75 stereocilia of lengths up to 30 pm and diameter 0.8 pm and containing more than 3000 actin filaments in a semicrystalline array. Microvilli (Fig. 1-6) contain longitudinal arrays of actin filaments. 

There are two basic forms of sonar, active and passive. Passive sonar depends on the sound produced by the object observed and a simple, direct listening can be employed, though there are usually a transducer (to convert the acoustic... 

Musicians are today used to having control over the loudness of the sounds produced by their instruments. The piano is actually short for piano-forte which means soft-loud. The piano was an improvement over the harpsichord, which did not have any significant control over loudness. 

The bright yellow lamellarian gastropod Marseniopsis mollis collected at McMurdo Sound produces the feeding deterrent homarine.51 Homarine is widely distributed in marine phyla and has been suggested to serve as an osmolyte.165... 

Almost all commerical sirens are used for fire and air raid warning systems. They have frequencies in the 250-500 Hz range and produce acoustic power in the 100-1000 watt range and are not very efficient sound producers. We have, therefore, developed the technology to design high efficiency reliable sirens. A typical example of a 600 acoustic watt siren is shown in Figure 10. The... 

This formula is reminiscent of the famous relationship that was discovered by Pythagoras to exist between the pitch of sound produced by the plucked string of a lyre and the effective length of the string. Based on this... 

Briefly the action taking place is as follows When the column is made to resonate by adjustment of the reflector on the end opposite to the sound-producing mechanism, the radiated and reflecting waves interfere in such a manner as to produce a standing wave. The nodes and antinodes correspond to minimum and maximum intensities of sound. 

An open receiving room (lm x lm, 50cm in depth) filled with sand was included as a mock receiving room. For measuring acceleration,ground vibration and the sound produced by the explosion, sensors were placed at various points as shown in Figure 5.26. No damage was noticed inside the mock shed. 

For each package of Energel MA-7 30mmS(100g in weight), the sound produced by its explosion was measured under six different sets of conditions. Table 5.7 shows the... 

Table 5.7 The sound produced by explosions under various conditions (dB).

A single container of explosive was buried in the sand right side up in the center of the open receiving room. It was filled with about 175g of explosive, topped with a 15cm length of sand, and was then exploded. The differences between the sound produced by this explosion and the other explosions under different conditions are shown in Table 5.9. 

Some leafhoppers use rather weak, species-specific sounds to communicate with each other. These leafhoppers produce their noises using structures known as tym-bals, which are anatomically similar to the much-louder sound-producing organs of cicadas. 

Sounds produced by humans can also interfere with the ability of animals to communicate. Such interference can inhibit an animaPs ability to protect itself, to find food, and to live a normal life. For example, ships emit low-frequency sounds that interfere with whale communications. Other human noises can frighten whales away from their normal migration routes. In the desert, kangaroo rats Dipodomys spp.) exposed to the roar of a dune buggy lose their ability to hear snakes approaching. Japanese quail (Coturnix Coturnix Japonicd) have to call much louder than usual when they live in a noisy environment. Sooty terns (Sterna fuse at a) have been observed to abandon their nests when jets create sonic booms. Intense bursts of noise have also caused condors (Gymnogyps californianus) to abandon their nests. 

Ring modulation and synchronization go beyond this to create interactive effects, in which a parameter controlling one voice also affects the sound produced by a second voice. In both cases, the special effect is created by a difference in the frequencies (pitches) of the two voices. 

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