A Psychoacoustic Quality Criterion for Path-Traced Sound Propagation.

In developing virtual acoustic environments, it is important to understand the relationship between the computation cost and the perceptual significance of the resultant numerical error. In this article, we propose a quality criterion that evaluates the error significance of path-tracing-based sound propagation simulators. We present an analytical formula that estimates the error signal power spectrum. With this spectrum estimation, we can use a modified Zwicker's loudness model to calculate the relative loudness of the error signal masked by the ideal output. Our experimental results show that the proposed criterion can explain the human perception of simulation error in a variety of cases.

A Case of Cystic Intrahepatic Cholangiocarcinoma Mimicking a Cyst.

ABSTRACT: Intrahepatic cholangiocarcinoma (ICC) classically presents as irregular soft tissue lesions. Very rarely, ICC may manifest as a predominantly cystic mass. Here, we describe a 59-year-old man who was referred to the hospital due to abdominal pain. The presentation was highly suggestive of a hepatic cyst based on MRI. 18F-FDG PET/CT could not exclude a malignant hepatic tumor due to the high metabolism in the margin. Subsequently, the patient underwent a left hemihepatectomy. Histopathology revealed malignant ICC.

Microstructure and Tensile Properties of Graphene-Oxide-Reinforced High-Temperature Titanium-Alloy-Matrix Composites.

In this study, graphene-oxide (GO)-reinforced Ti-Al-Sn-Zr-Mo-Nb-Si high-temperature titanium-alloy-matrix composites were fabricated by powder metallurgy. The mixed powders with well-dispersed GO sheets were obtained by temperature-controlled solution mixing, in which GO sheets adsorb on the surface of titanium alloy particles. Vacuum deoxygenating was applied to remove the oxygen-containing groups in GO, in order to reduce the introduction of oxygen. The compact composites with refined equiaxed and lamellar α phase structures were prepared by hot isostatic pressing (HIP). The results show that in-situ TiC layers form on the surface of GO and GO promotes the precipitation of hexagonal (TiZr)6Si3 particles. The composites exhibit significant improvement in strength and microhardness. The room-temperature tensile strength, yield strength and microhardness of the composite added with 0.3 wt% GO are 9%, 15% and 27% higher than the matrix titanium alloy without GO, respectively, and the tensile strength and yield strength at 600 °C are 3% and 21% higher than the matrix alloy. The quantitative analysis indicates that the main strengthening mechanisms are load transfer strengthening, grain refinement and (TiZr)6Si3 s phase strengthening, which accounted for 48%, 30% and 16% of the improvement of room-temperature yield strength, respectively.