Abstract: In this paper, four kinds of block diffraction models were proposed on the basis of the uniform geometrical theory of diffraction, and these models were validated by experiments with 45 GHz millimeter wave in the laboratory. The results are in agreement with the theoretical analysis. Some errors exist in the measurement results because of the unsatisfactory experimental environment. S...

This study aimed to clarify how composition and water immersion of home reliners affect the attenuation of the transmitted load. To conduct a transmitted load measurement, we used three different home reliners (Tafugurippu Pink A, Liodent Pink, and Cushion Correct), which were combined acrylic resin disks. They were immersed in distilled water and then placed on a silicone quasi-mucosa (φ20×1.5...

The attenuation spectra obtained from ultrasonic measurement is applied to estimate the particle concentration in general purpose polystyrene (GPPS) /GB (glass beads) composites by a differential scheme. Composite samples with particle radium 80 μm are tested at five volume fractions ranging from 6 % to 40 %. The longitudinal attenuation characteristics of these samples are found to depend mark...

spect detects γ-rays from administered radiopharmaceutical within the patient body. γ-rays pass through different tissues before reaching detectors and are attenuated. attenuation can cause artifacts; therefore different methods are used to minimize attenuation effects. in our study efficacy of chang method was evaluated for attenuation purpose, using a custom made heart phantom. due to differe...

Atmospheric attenuation loss between the heliostat field and receiver has been recognized as a significant source of loss in Central Receiver Systems. In clear sky situations, extinction of Direct Normal Irradiance (DNI) is primarily by aerosols in the atmosphere. When aerosol loading is high close to the surface the attenuation loss between heliostat and receivers is significantly influenced b...

Measure errors in economic data are pervasive and nontrivial in size. The presence of measurement errors causes biased and inconsistent parameter estimates and leads to erroneous conclusions to various degrees in economic analysis. The importance of measurement errors in analyzing the empirical implications of economic theories is highlighted in Milton Friedman’s seminal book on the consumption...

Environmental epidemiologic studies are often hierarchical in nature if they estimate individuals' personal exposures using ambient metrics. Local samples are indirect surrogate measures of true local pollutant concentrations which estimate true personal exposures. These ambient metrics include classical-type nondifferential measurement error. The authors simulated subjects' true exposures and ...

Conventional resonant bar tests allow the measurement of seismic properties of rocks and sediments at low frequencies (several kilohertz). However, the tests require a long, slender sample which is often difficult to obtain from the deep subsurface and weak and fractured formations. We present an alternative low-frequency measurement technique to the conventional resonant bar tests. This techni...

Department of Physics of Molecular Imaging Systems, Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany Despite promising advances, attenuation correction of PET data remains challenging in PET/MRI. Known approaches to estimating attenuation maps from PET emission data take into account only true coincidences and fail to completely determine the attenuation map...

Background: This study aims to investigate radiation beam geometry of Cyberknife beam and change in dosimetric characteristics of six megavoltage (6MV) flattening filter free (FFF) beam after passing through high density cadmium free compensator alloy.Material and Methods: In this experimental study, changes in FFF beam dosimetric characteristics after passing through compensator alloy wa...