Effects of double layer porous asphalt pavement of urban streets on noise reduction

AbstractRoad traffic is the major noise source that impacts the largest numbers of city dwellers. Urban traffic noise control at the source typically involves providing quieter i.e. low noise pavement and regular maintenance. The aim of this paper is to propose a double-layer porous asphalt pavement for keeping the traffic noise at a low level with good durability. It contains the top layer of fine aggregates and bottom layer of course aggregates. The noise-absorption performance of this asphalt pavement is evaluated by adjusting the parameters of the pavement structure simulated in air–solid coupled numerical models. The reduction of noise by using the newly proposed asphalt pavement is compared with those of the traditional pavements such as the thin surfacing (TSF) with small aggregates and rubberized asphalt pavement (RAP). The results from the outdoor noise tests for the double-layer porous asphalt pavement verifies the virtual pavement models and noise reduction effects in practice. This asphalt pavement is designated to lower the noise level of urban road traffic and boost the living environments of the city dwellers

Noncontact Three-Dimensional Diffuse Optical Imaging of Deep Tissue Blood Flow Distribution

The present invention provides for three-dimensional reflectance diffuse optical imaging of deep tissue blood flow distribution that removes the need for probe-tissue contact, thereby allowing for such technology to be applied to sensitive, vulnerable, damaged, or reconstructive tissue. The systems utilize noncontact application and detection of near-infrared light through optical lens and detection through a linear array or two-dimensional array of avalanche photodiodes or a two-dimensional array of detectors provided by charge-coupled-device (CCD). Both further feature a finite-element-method (FEM) based facilitation to provide for three-dimensional flow image reconstruction in deep tissues with arbitrary geometries

Compact Low-Cost Fiberless Diffuse Speckle Contrast Flow-Oximeter

A low-cost compact fiberless diffuse speckle contrast flow-meter includes a small laser diode and a 2-dimensional imaging device such as a charge coupled device (CCD) or complementary metal oxide semiconductor (CMOS) for directly contacting the tissue and measuring a parameter such as blood flow in a deep/thick volume of tissue (up to 10 mm depth). The small laser diode is fixed at a certain distance (0 to 20 mm) from the imaging device and directly contacts the tissue. Light emitted from the laser diode penetrates through the tissue and reflects back to the imaging device without passing through any lenses or fibers. One or more additional laser diodes may be added for producing light at different wavelengths, and the combination of measurements taken by the imaging device at the different wavelengths allows for measuring additional parameters, such as both blood flow and blood oxygenation