The measurement of the acoustic properties of highly attenuative materials such as bitumen is very difficult. One possibility is to use measurements of the extent to which filling a cylindrical waveguide with the material affects the dispersion relationship of the cylinder. Torsional modes have been excited using piezoelectric transducers placed at one end of the cylinder, while the phase veloc...

RATIONALE Low-attenuation areas assessed by computed tomography reflect the extent of pathological emphysema and correlate with airflow limitation and mortality in patients with chronic obstructive pulmonary disease. The cumulative size distribution of low-attenuation area clusters follows a power law characterized by an exponent, D. The values of D reflect the complexity of the terminal airspa...

In order to enhance the fiber attenuation during melt-blown process, a pair of air nozzle, which could erupt airflow as secondary airflow, below spinning die was arranged and used. Firstly, effect applying on whole explored by Computational Fluid Dynamics (CFD) simulation. The simulation results demonstrate interactive relationship between primary from airflow. Then, velocity at conditions with...

In many environments a large portion of particulate material is contained in aggregated particles; however, there is no validated framework to describe how aggregates in the ocean scatter light. Here we present the results of two experiments aiming to expose the role that aggregation plays in determining particle light scattering properties, especially in sediment-dominated coastal waters. Firs...

The cold-adapted B/Ann Arbor/1/66 influenza virus (ca B/AA/1/66) expresses temperature-sensitive (ts), cold-adapted (ca) and attenuation phenotypes. Reassortants which inherit one or more genes from ca B/AA/1/66 and all other genes from a virulent, wild-type influenza virus, B/Houston/1732/76, were produced and evaluated in order to identify the gene(s) responsible for the ts, ca and attenuatio...

We investigate the attenuation structure of the Earth's inner core and its relationship to the velocity structure globally and along various sampling directions, by studying the amplitude ratios and the differential travel times of the PKiKP–PKIKP and PKPbc– PKIKP phases. Our observations reveal that the amplitude ratios of these core phases, like the differential travel times, vary in both sam...

The 2014 Ms 6.5 (Mw6.1) Ludian earthquake occurred in the eastern Sichuan-Yunnan border region of western China. This earthquake caused much more severe engineering damage than the usual earthquakes with the same magnitude in China. The National Strong Motion Network obtained large set of ground motion recordings during the earthquake. To investigate the engineering interested characteristics o...

Background: In this study, a method for linear attenuation coefficient calculation was introduced.Methods: Linear attenuation coefficient was calculated with a new method that base on the physics of interaction of photon with matter, mathematical calculation and x-ray spectrum consideration. The calculation was done for Cerrobend as a common radiotherapy modifier and Mercury.Results: The values...

background: in this study, a method for linear attenuation coefficient calculation was introduced. methods: linear attenuation coefficient was calculated with a new method that base on the physics of interaction of photon with matter, mathematical calculation and x-ray spectrum consideration. the calculation was done for cerrobend as a common radiotherapy modifier and mercury. results: the valu...