Attenuation factor

Amplifier bandwidth. The range of signal frequencies over which an amplifier is capable of undistorted or unattenuated transmission. An operational amplifier should transmit DC voltage accurately the upper (bandwidth) limit is defined as the 3-dB point (attenuation factor of two). Because bandwidth can vary with gain, the product of gain x bandwidth can be a more useful parameter. 

Filters have a time constant r = R x C which increases the damping of the measuring instrument. The time constant depends on the required attenuation and the interfering frequency, but not on the internal resistance of the measuring instrument. The time constants of the shielding filter are in the same range as those of the electrochemical polarization, so that errors in the off potential are increased. Since the time constants of attenuation filters connected in tandem are added, but the attenuation factors are multiplied, it is better to have several small filters connected in series rather than one large filter. 

The attenuation factor for a receptor at the center of a finite plane uniform source of radiation is given by equation 8.3-7, where b is the radius and z is the height of the receptor above the plane. If there is... 

In order to compute the thermal radiation effects produced by a burning vapor cloud, it is necessary to know the flame s temperature, size, and dynamics during its propagation through the cloud. Thermal radiation intercepted by an object in the vicinity is determined by the emissive power of the flame (determined by the flame temperature), the flame s emissivity, the view factor, and an atmospheric-attenuation factor. The fundamentals of heat-radiation modeling are described in Section 3.5. 

The atmospheric attenuation factor takes into account the influence of absorption and scattering by water vapor, carbon dioxide, dust, and aerosol particles. One can assume, as a conservative position, a clear, dry atmosphere for which = 1. 

Estimate the radiation received at a receptor. With an attenuation factor of 1, the radiation received by a vertical receptor at a distance X from the tank can be calculated from ... 

Most infrared monitoring systems or instruments provide special filters that can be used to avoid the negative effects of atmospheric attenuation of infrared data. However the plant user must recognize the specific factors that will affect the accuracy of the infrared data and apply the correct filters or other signal conditioning required negating that specific attenuating factor or factors. 

Diffusion Through Separators Like current flow, the diffusion of dissolved components through separators will be delayed by decreasing porosity and increasing tortuosity. The attenuation factor of diffusion, 8d (= DID f), usually coincides with that of conduction. 

The amplitude attenuation factor, 1 + (tu/Ai)2 for nuclides satisfying relation [14], for various values of Ax and T are presented in figure 9. It is obvious from figure 9 that the attenuation is minimal when Ai > u>, i.e., when the removal residence time of the nuclide from sea water is less than the period in the variation of cosmic ray intensity. 

Figure 9. Calculated attenuation factors for various values of T (period in the sinusoidal cosmic ray intensity variations) and A (the total rate constant). See section on deep-sea sediments and historical records for discussion.

In Table 2 we present the expected attenuation factors of 10Be. A residence time of 200 years ( = 5 x 10-3 yr-1) for 10Be in sea water and a mixed layer thickness of 10 cm have been assumed in the calculations. 

Table 2. Calculated Attenuation Factors for 10Be at Deposition on Ocean Floor and Within Sediments.

In the preceding discussion, we have calculated the attenuation factors for 10Be for three periods, 200, 7 x 103 and 10s years. Of these the 200 and 7000 year periods are well established and have been ascribed to solar cycle variations and earth s magnetic field excursions, respectively. For detailed calculations on the effect of these variations on the production rates of isotopes by cosmic rays reference is made to Castagnoli and Lal, 75.)... 

Fowler PA, Spears N (2004) The cultured rodent follicle as a model for investigations on gonadotropin surge-attenuating factor (GnSAF) production. Reproduction 127 679-... 

Fowler PA, Sorsa-Leslie T, Cash P, Dunbar B, Melvin W, Wilson Y, Mason HD, Harris W (2002) A 60-66 Kda protein with gonadotropin surge attenuating factor bioactivity is produced by human ovarian granulose cells. Mol Hum Reprod 8 823-832... 

Fig. 8.9 (a) Round trip amplitude attenuation factor and (b) OFF resonance transmission of the singly coupled microring as a function of W and R0. Reprinted from Ref. 45 with permission. 2008 Institute of Electrical and Electronics Engineers... 

It was found that a better representation of non-specific interactions between solvents and the monosubstituted dipolar trimethylammonium ions is gained from the product of tt and the solvent dipole moment (/x). The obtained results were compared with the gas-phase basicity and the solvent attenuation factors (SAF) were calculated". 

An = the measured area of the N2H4 peak multiplied by its signal attenuation factor... 

EAj = the sum. of all the measured peak areas in the signal attenuation factors... 

Figure 1. Chromatograms after desorption of the EA (A) or DEA (B) Y zeolite, carried out with the cdbalt(III) hexamine chloride solution (1) non-heated, AF 1024 (2 and 8, respectively) heated in the presence of air, AF 256 for 70 hr at 150° and for 50 hr at 250° (4) heated for 50 hr at 250°, AF 256, in the presence of 400 torr of 02 (5) heated for 50 hr at 250° under vacuum (5 X 10 torr), AF 512 (6) same as (5), hut observed with a catharometer detector, AF 4- Unless indicated, the detector was a flame ionization detector. AF is the attenuation factor.

A more rigorous approach includes a transmission coefficient, k, which is a multiplication factor equal to the fraction of the transition state that proceeds to products. The transmission coefficient is generally close to 1.0 for simple reactions. There can be a large attenuation factor for complex reactions because of... 

The data calculated from satellite readings of extraterrestrial solar flux may be accurate for cloudless and aerosol free skies. In the case of cloud covered skies the retrieval of aerosol attenuation factor becomes extremely complicated. In the case of cloudless skies, the aerosol attenuation factor q for UV flux at the earth s surface depends on the optical (and chemical properties) of he aerosol, i.e. as to whether the aerosol is absorbing or non absorbing at the wavelengths of interest. This is well depicted in figure 9 below. (Krotkov et al., 1998). 

Figure 9 Aerosol attenuation factor I) (A)= 1- F er (A)/ Fckjr (A) at 325 nm for nonabsorbing (triangles) and absorbing (diamonds) aerosols as a function of the TOMS Lambert-equivallent reflectivity (R-0.05)/0.9 (the true surface reflectivity Rj= 0.05). Solar zenith angle is 50°, satellite zenith angle 32° and azimuth 90°...

Figure 10 Global map of aerosol UV-flux attenuation factor rj= 1-F,er/Fd(air = l-exp -(k/b)AI, estimated from the aerosol index map. The conversion factor k/b= 0.25, was obtained from the clear sky radiative transfer calculations, assuming single layer (dust or smoke) between 2and 4 km and solar zenith angle 30°. The map shows that aersosol absorption can produce very large reduction in UV flux ( 50%) in certain parts of the world (from plate 2 of Krotkov et al. 1998).

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