Hearing, characteristics

Instruments for measuring occupational noise have modified measuring scales ( A weighting) to match the ear s hearing characteristics, hence the occupational noise unit is dB(A). 

The shapes of the weighting curves most commonly used are shown in Figure 20.5 and the sound pressure level curve that follows the hearing characteristic of the ear is termed the A weighted curve. This curve gives the most widely used unit (dBA) for quantifying a noise level. Other curves on the weighting network are the B, C and D. Curves B and C are not commonly used and D is sometimes used for aircraft noise. 

Flavor has been defined as a memory and an experience (1). These definitions have always included as part of the explanation at least two phenomena, ie, taste and smell (2). It is suggested that in defining flavor too much emphasis is put on the olfactory (smell) and gustatory (taste) aspects (3), and that vision, hearing, and tactile senses also contribute to the total flavor impression. Flavor is viewed as a division between physical sense, eg, appearance, texture, and consistency, and chemical sense, ie, smell, taste, and feeling (4). The Society of Flavor Chemists, Inc, defines flavor as "the sum total of those characteristics of any material taken in the mouth, perceived principally by the senses of taste and smell and also the general senses of pain and tactile receptors in the mouth, as perceived by the brain" (5). 

Observable Characteristics - Physical State (as shipped) Liquid Color Pale yellow Odor. Weak. Physical and Chemical Properties - Physical State at 15 XI and I atm. Liquid Molecular Weight Not pertinent Boiling Point at 1 atm. Very high Freezing Point -4, -20,253 Critical Temperature Not pertinent Critical Pressure Not pertinent Specific Gravity 0.22 at 20 °C (liquid) Vapor (Gas) Specific Gravity Not pertinent Ratio of Specific Heats of Vapor (Gas) Not pertinent Latent Heat of Vaporization Not pertinent Hear qfComhitfrio/i (est.)-16,000, -8,870, -31 Heat of Decomposition Not pertinent. 

The air distribution method and dimensioning of the air supply devices are important factors in determining the accumuiation of hear and contaminants. Examples of this are presented in Section 8.4. After the behavior of the air distribution method and devices are known, the characteristic effects ot the other airflow elements can be calculated. 

The first three characteristics are considered to be the positive symptoms of the disorder. The fourth are described as negative symptoms although they can be divided into true negative symptoms, i.e. diminished emotions and speech and reactive ones, i.e. social apathy and withdrawal brought on by the positive symptoms. Schizophrenics do not have a split personality. Normally their reaction to the positive symptoms is to withdraw quietly but occasionally they will react violently to the voices they hear and shout at them. 

Only a small proportion of the methods available, mainly for diagnostic purposes (Lezak, 1995, p. 385), have been used in drug experiments. Special mention should be made of the determination of criticalflicker fusion frequency (CFF) and of tachistoscopic trials, Le. of methods directed at the characteristics of visual perception. In contrast, drug effects on hearing have rarely, and those influencing senses of touch, smell and taste have hardly ever, been investigated (Turner, 1971). 

Fig. 3. 27 Discharge characteristics of 75 mAh zinc-silver oxide hearing aid cell under continuous load at room temperature. (By kind permission of P. Ruetschi, Plenary lecture, ISE. Venice. 1980.)...

A characteristic is the appearance of "nemaline bodies" or thickened Z-discs containing Z-disc proteins. Some hereditary diseases involve nonmuscle myosins. Among these is Usher syndrome, the commonest cause of deaf-blindness. The disease, which results from a defect in the myosin VIA gene, typically causes impairment of hearing and retinitis pigmentosa (Chapter 23).hh... 

The properties of the most prevailing hydrogen-hearing compound, water, are given under Waler. The characteristics of acids are attributed essentially to the presence ol hydrogen ions. These topics are treated under Acids and Bases and pH (Hydrogen Ion Concentration ... 

ANSI, 1987] ANSI (1987). ANSI S3.22-1987 Specification of Hearing Aid Characteristics. Technical report, American National Standards Institute. 

Our lives are for the most part spent in reverberant environments. Whether we are enjoying a musical performance in a concert hall, speaking to colleagues in the office, walking outdoors on a city street, or even in the woods, the sounds we hear are invariably accompanied by delayed reflections from many different directions. Rather than causing confusion, these reflections often go unnoticed, because our auditory system is well equipped to deal with them. If the reflections occur soon after the initial sound, the result is not perceived as separate sound events. Instead, the reflections modify the perception of the sound, changing the loudness, timbre, and most importantly, the spatial characteristics of the sound. Late reflections, common in very reverberant... 

Since the speed rises while your voice box remains the same size, the frequency v =. vSoUndA of the sound disturbances you make goes up. As the sound exits the bag, it creates a pressure wave in the air with the same characteristic frequency (if the sound wave inside is hitting the wall of the bag 1000 times per second, the bag will vibrate a little 1000 times per second), and hence you hear a higher pitched note. 

These two examples clearly demonstrate the potential for development and manipulation of fatty acid profiles to improve plant oil characteristics for industrial use, and in the case of HEAR, to improve the economics of processing, reducing costs to the end user. However, one of the downsides of manipulating fatty-acid profiles in crops that have both food and non-food uses is the need to keep crops separated on the farm and in the post-farm-gate supply chain, to avoid risks of contamination of either chain. 

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