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New indirect estimation technique for the determination of the moisture diffusivity from transient moisture content profiles measured by means of X-ray radiography
Published in J. Carmeliet, H. Hens, G. Vermeir, Research in Building Physics, 2020
J. Carmeliet, T. Van Besien, S. Roels
with I0 the incoming intensity of X-ray photons, Idrv and Iwet the intensity of X-ray photons after passing the dry and wet material, d the thickness of the material, μdry and μl the linear attenuation coefficient for dry material and liquid water, ρl the density of liquid water. The attenuation coefficient depends on the density and atomic number of the material and the used X-ray energy. Rearranging Equation 8, the moisture content w is given by w=−ρlμldln(IwetIdry)=−ρlμld(ln(Iwet)−ln(Idry))
X-Ray and Computed Tomography
Published in Ravishankar Chityala, Sridevi Pudipeddi, Image Processing and Acquisition using Python, 2020
Ravishankar Chityala, Sridevi Pudipeddi
In addition to the attenuation coefficient, the characteristics of a material under x-ray can also be defined using the half-value layer. This is defined as the thickness of material needed to reduce the intensity of the x-ray beam by half. So from Equation 13.3 for a thickness δx = HVL (half value layer), I=I02
Cumulative distress curve estimation from micromechanical asphalt model
Published in Eyad Masad, Amit Bhasin, Tom Scarpas, Ilaria Menapace, Anupam Kumar, Advances in Materials and Pavement Performance Prediction, 2018
I.O. Onifade, Y. Dinegdae, B. Birgisson
X-ray computed tomography (CT) is an advanced non-destructive characterization technique used in visualizing the interior of an opaque object with the aim of obtaining digital information about the constituent of the material. CT images of an object are a result of the mapping of the objects attenuation coefficient. The attenuation coefficient is a measure of the ability of a material to absorb or scatter light. In this paper, X-Ray CT is used to obtain the internal structure of an asphalt concrete core sample. The three dimensional digital sample data is obtained at a scanning resolution of 105 microns. DIP techniques are used to enhance, segment and quantify the different phases in the material. The final segmented image consists of 58.2% aggregates, 36.6% mastic by volume. The air voids content is 5.2%. The mastic is considered as a mixture of the binder, fines and aggregate particles with Feret diameter less than 2.34 mm. A slice from the stack of CT images is selected and used for micromechanical analysis. An image of the final segmented CT slice is presented in Figure 1.
Monte Carlo simulation for the interaction characteristics of gamma-rays with several tissues and water as a tissue substitute
Published in Radiation Effects and Defects in Solids, 2023
Urkiye Akar Tarim, Orhan Gurler, Latif Korkmaz
Primary radiation interaction data, linear attenuation coefficients, tabulated in Table 3 for selected body tissues and water as being tissue substitutes have been used to calculate the other interested interaction quantities, half-value layer and the tenth-value layer. Calculation results of these parameters have been presented in Tables 4 and 5. Herein, the important consequence considered from the calculations and these prepared tables that the half-value layer and tenth-value layer obtained with americium gamma radiation are somewhat smaller than those of technetium, iodine, sodium and cesium radiation. This shows that the americium radiation components are of lower energy than those of technetium, iodine, sodium and cesium, which predominate at such a moderate attenuation; another conclusion to be drawn from this is that the appropriate material thickness will be greater than those of technetium, iodine, sodium and cesium radiation for attaining the same radiation attenuation factor. Also, in these tables, the values for half-value layer and tenth-value layer thicknesses that were achieved by using both theoretically and experimentally obtained attenuation coefficient values have been presented.
Assessing the effective penetration depth of mid-wave infrared radiation in water for fluid dynamic measurements
Published in Quantitative InfraRed Thermography Journal, 2023
where is the initial radiation flux and is the flux at a distance . The attenuation coefficient, , is determined by the physical and chemical properties of the medium that absorbs and scatters the radiation energy. In the infrared spectral region, scattering by pure liquid water is negligible compared to absorption, so that in Equation (1) can be replaced by the linear absorption coefficient . The accurate knowledge of the water absorption coefficient is essential for a wide range of optical applications, and number of research papers has been published regarding its spectral variations [20–23], as well as their corrections for temperature and salinity [24,25]. In most of the studies, the penetration depth of infrared radiation in water is estimated using the transmittance method at each particular wavelength over the studied range. Typically, two infrared transparent plates are used to fix the water film thickness; however, very little studies properly indicate whether the optical properties of the plates are used to correct the measured absorption spectra.
Enhanced Bentonite/PVA Matrix for Advanced Shielding Applications
Published in Nuclear Technology, 2022
Fawzy Hammad Sallam, Eman Mohamed Ibrahim, Sayed Fahmy Hassan, A. Omar
The study of gamma-ray and X-ray attenuation of different materials started in 1952 (Refs. 3 and 4), so many studies have come along with techniques of various attenuation calculations.5 Different attenuation coefficients have been investigated, such as linear and mass attenuation coefficients. The linear attenuation coefficient µ represents the probability of interaction between gamma rays and shielding material per unit path length and is considered the main factor for the penetration and diffusion of gamma rays in a shielding medium.6 Gamma-ray attenuation depends on the shielding material’s atomic number, photon energy, and density. The mass attenuation coefficient is defined as the linear attenuation coefficient per unit mass of the shielding material.7 According to Lambert’s law, linear attenuation µ can be determined as presented in Eq. (1):