Premature delivery is the leading cause of infant mortality in the United States. Currently, premature delivery cannot be prevented and new treatments are difficult to develop due to the inability to diagnose symptoms prior to uterine contractions. Cervical ripening is a long period that precedes the active phase of uterine contractions and cervical dilation. The changes in the microstructure o...

The Sound attenuation and dispersion in saturated gas-vapor-droplet mixture in the presence of evaporation has been investigated theoretically. The theory is based on an extension of the work of Davidson (1975) to accommodate the effects of nonlinear particle relaxation processes of mass, momentum and energy transfer on sound attenuation and dispersion. The results indicate the existence of a s...

IAEA code of practice TRS-457 states that standard phantoms should offer the same primary attenuation and scatter production as relevant body section of a representative patient. Material cost, availability and dimensional stability must also be considered. The goal of this study is to determine the attenuation coefficient of printed ABS and PLA in standard X-ray beams, verifying if phantoms pr...

Generally, computerised tomography (CT) is an X-ray based non-destructive testing method that was developed for medical purposes in the seventies and introduced for industrial applications during the eighties. CT produces maps of the X-ray linear attenuation coefficient of an object’s interior; presented either as cross section images (two-dimensional CT) or as volume information (three-dimensi...

Porous concrete is a mixture of cement and water that may contain fine grains, which play a role in water transfer and permeability. Porous concrete can act as a drain to pass rainwater and recharge groundwater. In this study, 25%, 50%, 75%, and 100% zeolite were used to replace the coarse aggregates in porous concrete. The effects of the zeolite on the compressive strength, permeability coeffi...

elastic energy of seismic wave is lost through propagation into the earth. various factors affect seismic energy. some of them are frequency independent and recovered in processing steps. but other factors such as intrinsic absorption of medium are frequency dependent and cannot be recovered by processing methods. lost energy caused by these factors is called attenuation. there are various meth...

In order to achieve a fair description of radon transport through concrete certain information is needed on the concrete structure, porosity and permeability, on processes causing the transport of radon, on radon’s interaction with environment, factors favouring the generation of radon, etc. The concrete characteristics (that depend on its composition and especially on the W/C ratio) which infl...

The present work experimentally investigates the correlations between ultrasonic attenuation coefficient and void content with the porosity 0.03%-4.96% of the carbon fiber-reinforced composite (CFRC) samples. The ultrasonic echo immersion bottom reflection technique with 5MHz flat probe is adopted to determine the attenuation coefficient and the metallographic microscope is used to measure the ...

Polychromatic x-ray beams traveling though material are prone to beam hardening, i.e., the high energy part of the incident spectrum gets over represented when traveling farther into the material. This study discusses the concept of a mean attenuation coefficient in a formal way. The total energy fluence is one-to-one related to the traveled distance in case of a polychromatic beam moving throu...