Sound measurement

This standard gives methods and proeedures for speeifying the sound emissions of gas turbine installations for industrial, pipeline, and utility applieations. Ineluded are praetiees for making field sound measurements and for reporting field data. This standard ean be used by users and manu-faeturers to write speeifieations for proeurement, and to determine eom-plianee with speeifieation after installation. Information is ineluded, for guidanee, to determine expeeted eommunity reaetion to noise. 

I do hope that this book will not only find a wide audience, but that it will also contribute something to progress in the world. This may sound somewhat grand and optimistic, but is it forbidden to dream that next century will indeed bring real progress to mankind Can this progress be based on anything else except scientific developments If this is to be so, then what other than sound measurement data can be the basis Sound measurements mean that data are accurate for the intended purpose and that the uncertain is known and taken into full account. 

The unit of sound measurement is the decibel, defined by the expression ... 

Sound Speed Measurements. The most precise values of compressibility at 1 atm can be determined from speed of sound measurements. The adiabatic compressibility (63) is related to the speed of sound (u) by... 

Unfortunately, and probably unavoidably, from the earliest research until the present, investigators have not used the same standardization process. Furthermore, standardization practices within different research groups have only rarely followed the meticulous series of in-house calibrations, verifications, and interlaboratory comparisons long prescribed by the conununity of measurement specialists. Several quantitatively crucial studies, however, have followed sound measurement procedures (see, e.g.. Chapter 9). 

Silvery-gray metal hexagonal crystal structure malleable, ductile, and soft enough to be cut with a knife density 8.223 g/cm melts at 1,359°C vaporizes at 3,221°C resistivity llhxlCH ohm-cm at 25°C Young s modulus 5.75xl0n dynes/cm2 (from velocity of sound measurements) shear modulus 2.28 dynes/cm2 Poisson s ratio 0.261 thermal neutron absorption cross section, 46 barns insoluble in water soluble in acids. 

K.H.L. Chau, R. Goehner, E. Drubetsky, H.M. Brady, W.H. Bayles, Jr., and RC. Pedersen. Pressure and sound measurement. In J.C. Webster, editor, Measurement, Instrumentation, and Sensors Handbook, 2nd Edition, Chap. 26. CRC Press, Boca Raton, 1999. 

C. L. Darner, An Anechoic Tank for Underwater Sound Measurements... 

O. KOEFOED —GEOSOUNDING PRINCIPLES, 1. RESISTIVITY SOUNDING MEASUREMENTS H.P. PATRA AND K. MALLICK —GEOSOUNDING PRINCIPLES, 2. TIME-VARYING GEOELECTRIC SOUNDINGS... 

Goodwin ARH, Trusler JPM (2003) Speed of sound. Measurements of the speed of sound. Thermodynamic properties from the speed of sound. In Goodwin ARH, Marsh KN, Wakeham WA eds) Experimental thermodynamics, vol VI measurement of the thermodynamic properties of single phases, IUPAC. Elsevier, Amsterdam... 

All materials subject to size reduction through grinding will exhibit a distribution of particle sizes, often skewed in shape, with the result that a single estimate of size will not represent the sample as a whole. In addition, the grinding of multiphase samples most often results in differential size reduction of hard and soft phases. In practice, the difficulty in obtaining an accurate estimate of individual particle sizes usually means that analysts make an informed guess at the value of D. Thus, the value used may be empirically based to achieve a desired phase abundance rather than a value based on sound measurement. Widespread misuse of microabsorption correction was clearly demonstrated in the lUCr quantitative phase analysis round robin. ... 

Traditional chemical techniques used to estimate total sediment toxicant concentrations poorly predict bioavailability and toxicity. Typically, organic compounds must dissolve in sediment porewaters or digestive fluids in order to be accessible for uptake by an organism (bioavailability). As traditional chemical techniques aim to extract the whole mass of toxicants associated with sediments, sediment concentrations often provide inaccurate estimates of bioavailability and toxicity. Organismal concentrations represent a more accurate and theoretically sound measure of bioavailability. 

In making sound measurements, several factors regarding the nature of the source should be considered. Whether the source is a true point source in space radiating spherically, or whether it is a hemispherical source close to one flat surface or a quarfer sphere between two flat surfaces, and so on, if will make a difference in how the measurement needs to be performed. However, a detailed discussion of measurement issues is beyond the scope of this chapter and the reader may use some of the more comprehensive... 

Sound level level of sound measured with a sound level meter and one of its weighting networks. When A-weighting is used, the sound level is given in dBA. 

Noise (see Chapter 8) is an important emission from a flare that must be adequately controlled to protect personnel in the vicinity of a flare event [47]. To study the effects of noise from flares, a sophisticated sound measurement system was designed for the flare test facility. It consists of state-of-the-art Briiel Kjeer technology and is powered by the latest Pulse Platform. This measurement system (see the photo in Figure 28.14) consists of five stages. 

Sound measurement system in use during a flare test. (From Hong, J., Baukal, C., Schwartz, R., and Fleifil, M., Chemical Engineering Progress, 102, no. 5,35-39,2006.)... 

Methods for the determination of virial coefficients can conveniently be classified as (a) p-V-T measurements, (b) speed of sound measurements, (c) Jonle-Thomson measurements, (d) refractive index and relative permittivity measurements and (e) vapour pressure and enthalpy of vaporization... 

Here, p is the amount-of-substanee density, equal to the reeiproeal molar volume. To carry out the numerical integration of these equations, initial values are required for two of the three quantities Cym,Z and (dZldT)p . For example, values for Z and (dZldT)p can be determined at evenly spaced densities along an initial isotherm when accurate gas-density data are known. Then, (dZldp )T can be calculated and combined with speed of sound data to give values for Cy at each density from the first of the equations above, and then f < Z/dT )p can be determined from the second equation. A simple predictor-corrector method is then used to determine Z and dZ/dT)p at a temperature AT from the reference isotherm. This process is then repeated to cover the range of thermodynamic states of the speed of sound measurements. Accurate coefficients in the virial equation of state can then be derived from the compression factors. 

The detection of erroneous assumptions lies at Che core of sound measurement science. It Is... 

Very precise speed of sound measurements were performed by Mehl and Moldover utilizing a spherical resonator and acoustic excitation of radial modes As... 

Literature data [2] speed of soimd measurement to obtain EOS parameters, [112] speed of sound measurement. 

For statements concerning the uncertainties of other techniques like millisecond and submicrosecond experiments, levitation, speed of sound measurement, microcalorimetry, etc., study of the original literature is advised. 

The requirements of a sound measurement system Some guiding thoughts... 

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