Attenuation constant

Lihou and Maund (1982) define attenuation constants for hydrocarbon flames through the atmosphere, which can vary from 4 x 10 m (for a clear day) to 10 m (for a hazy day). The mean value suggested by the authors is 7 x 10 m , which gives a transmissivity of ... 

The relative amplitude of the two curves will depend on the attenuation constant of the protected and unprotected structures, the spacing between them, and the distance between the two structures and the groundbed. The total effect at any point on the unprotected structure is obtained by adding together the two currents due to (a) and (b) as shown in curve NGN. ... 

Here, P0 is the input transmission power, and the parameters yc and ya are the coupling and attenuation parameters, respectively. They are expressed through the attenuation constant, a, the circumference, S, the effective refractive index, n, and the coupling coefficient, k, as follows ... 

FIGURE 5. The attenuation constant and the speed of sound vs frequency for a silicone rubber sample. 

U 3 — [0,1) be a function that returns a random number between 0 and 1, Maxit e 3 be the number of iterations of the Metropolis algorithm, a g a < 1 be an attenuation constant for reducing the temperature, Tq and be the initial and final temperatures. 

When the angle of incidence 6 is small enough, transmission losses for skew rays are equal in the first-order approximation to those for meridional rays with the same 6 [9]. Therefore, only meridional rays are considered in the present analysis. For the meridional ray, a power attenuation constant 2a (6) is calculated as... 

Ultrasonic experiments using laser induced phonon spectroscopy have been performed in a nematic liquid single crystal elastomer [48]. The experiments reveal a dispersion step for the speed of sound and a strong anisotropy for the acoustic attenuation constant in the investigated frequency range (100 MHz -1 GHz). These results are consistent with a description of LCEs using macroscopic dynamics [54-56] and reflect a coupling between elastic effects and the nematic order parameter as analyzed in detail previously [48]. 

The propagation constant of the transmission line with attenuation constant a and phase... 

Here, tj is the complex refractive index, y is propagation constant, a is attenuation constant and t is thickness of the shielding material. Ihe parameter skin depth (S = 1/a) is defined as the depth of penetration at which the incident EM radiation is reduced to 37% of its original strength. Now from... 

Experimentally, shielding effectiveness is measured using instrument called network analyzer (NA). Both scalar NA (SNA, which record only the magnitude of the incident, reflected, and transmitted signals) and vector NA (VNA, which also measures the associated phases) are used for shielding measurements [1,3]. Particularly, the VNA signals carry information about attenuation constant as well as dielectric/magnetic properties. 

If an absorbing sample is introduced into the cavity such that the absorption follows Beer s law (Equation (6.2)) for a single pass of the laser pulse through the medium, then this absorption (proportional to the attenuation constant a) simply adds to the per-pass cavity loss, resulting in a shorter ring-down time. Equation (6.4) thus becomes... 

Where, co = 27t f is the angular frequency, a is the attenuation constant and jS is the phase constant. In our case, considering frequencies in the MHz-range, the resistance per unit length is dominated by the skin effect and the conductance per unit length is mainly... 

There are two mechanisms that causes losses in waveguides dielectric losses and metal losses. In both cases, these losses cause the amplitudes of the propagating modes to decay as exp(—az), where a is the attenuation constant, measured in neper/meter. Typically, the attenuation constant is considered as the sum of two components a = cKdie + met) where aaie and aniet arc the dielectric and metal attenuation... 

The attenuation constant can be found directly from Eq. (4.14) simply by generalizing the dielectric wave number k to include the effect of the dielectric conductivity a. For a lossy dielectric, the wave number is given by 1 = + (u/jtne)). Thus, from Eqs. (4.13) and (4.14) the attenuation constant Q [Pg.327]

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