Knowledge of x-ray attenuation is essential for developing and evaluating x-ray imaging technologies. For instance, techniques to better characterize cysts at mammography screening would be highly desirable to reduce recalls, but the development is hampered by the lack of attenuation data for cysts. We have developed a method to measure x-ray attenuation of tissue samples using a prototype phot...

This paper examines the suitability of some propagation models for forest environments. To that end, the vegetation attenuation is augmented to the appropriate propagation models. The vegetation attenuation models considered here are the maximum attenuation (MA) model and the foliage attenuation model which were recommended by the International Telecommunications Union (ITU-R). The propagation ...

This study examined the attenuation characteristics of five FM system sound delivery options for a group of 10 adults and 15 children (5-13 years). Sound delivery options included a tube-fitting, lightweight headphones, a CROS earmold with tubing, a CROS earmold with a snap-ring, and a standard snap-ring earmold with a vent. Attenuation was defined as the difference between probe-tube microphon...

By using a CMOS compatible process technology, a MEMS variable optical attenuator (VOA) is characterized in terms of actuation mechanisms. A dual-fiber collimator is aligned perpendicularly to the micromirror in a three-dimensional (3D) free space configuration, where the micromirror is mechanically connected with an electromagnetic actuator and two sets of electrothermal actuators. Three types...

This paper investigates the influence of critical raindrop diameters on the specific rain attenuation in Durban (29◦52′S, 30◦58′E), South Africa. The total rainfall attenuation is evaluated by integrating over all the raindrop sizes and the differential change in the attenuation is observed over a given range of drop size diameters. The major contribution to the specific attenuation for the dro...

ABSTRACT: Frequent occurrence of seismic activities has drawn attention of various researchers, cutting across science and engineering discipline. The domain of earthquake geotechnical engineering has extended from determination of attenuation of seismic wave to providing suitable foundation under liquefied and unliquefied soil conditions. The seismic data can be fully intrepreated by use of se...

Underground rocks usually have complex pore system with a variety of pore types and a wide range of pore size. The effects of pore structure on elastic wave attenuation cannot be neglected. We investigated the pore structure effects on P-wave scattering attenuation in dry rocks by pore-scale modeling based on the wave theory and the similarity principle. Our modeling results indicate that pore ...

This paper presents the precise method to estimate the dependence of linear and mass attenuation coefficients of gamma rays on concentration of Manganese (II) chloride (MnCl2). The experiment was done using GSpec gamma spectroscopy system. The GSpec consists 2‖x 2‖ NaI (Tl) detector with Multichannel analyzer (MCA). The GSpec has built in 14 Pin PMT base.The GSPEC is pc based Gamma Ray Spectros...

Repeating a stimulus generally leads to a decreased response in neural activity compared to that for novel items. This neural attenuation provides a marker for stimulus-specific perceptual encoding and memory that can be detected using functional magnetic resonance imaging (fMRI). Although previously assumed to occur automatically whenever a stimulus is repeated, recent studies have begun to sh...

Skeletal muscle contains intramyocellular lipid droplets within the cytoplasm of myocytes as well as intermuscular adipocytes. These depots exhibit physiological and pathological variation which has been revealed with the advent of diagnostic imaging approaches: magnetic resonance (MR) imaging, MR spectroscopy and computed tomography (CT). CT uses computer-processed X-rays and is now being appl...