Experimental and numerical study of heat transfer through a synchronous belt transmission type AT10
Highlights • An experimental study on pulley-belt temperature measurement is presented.• The effects of torque, setting tension and angular speed on the belt.• A heat transfer model is proposed to calculate pulley-belt heat flux.• Validation based on experimental thermal surveys and thermocouple measures.• A comparative analysis between two heat fluxes (calculated and simulated) is done.
Analysis of transverse vibration in engine timing belt
Abstract The purpose of this study is to observe the generating mechanism and the reduction method of belt transverse vibration as a cause of timing belt noise. It is known that belt tension affects the transverse vibration. We have described the following two processes: First, the belt resonance frequency varies with the tension and the amplitude increases when the frequency equals the belt meshing frequency. Second, an excitation source exists in the belt tooth crest and bottom land, whose influence varies with the tension. Therefore, adjustment of pulley tooth height is confirmed to be effective for reducing the transverse vibration.
Imaging the Internal Structure of an Alpine Glacier via L-Band Airborne SAR Tomography
In this paper, we report results from the analysis of 3-D L-band airborne synthetic aperture radar (SAR) acquisitions acquired in March 2014 over the Mittelbergferner glacier, Austrian Alps, during the European Space Agency (ESA) campaign AlpTomoSAR. The campaign included coincident in situ measurements of snow and ice properties and ground-penetrating radar (GPR) data acquired at 600 and 200 MHz over a total length of 18 km. Radar data were acquired by repeatedly flying an L-band SAR along an oval racetrack at an altitude of about 1300 m over the glacier, such that two data stacks from opposite views are obtained. Data from all passes were coherently combined to achieve 3-D resolution capabilities, resulting in the generation of 3-D tomographic SAR (TomoSAR) cubes, where each voxel represents L-band radar reflectivity from a particular location in the 3-D space at a spatial resolution on the order of meters. TomoSAR cubes were finally corrected to account for wave propagation velocity into the ice, which was a necessary step to associate the observed features with their geometrical location, hence enabling a direct comparison to GPR data. The TomoSAR cubes show the complexity of the glacier subsurface scattering. Most areas are characterized by surface scattering in proximity of the ice surface, plus a complex pattern of in-depth volumetric scattering beneath and scattering at the ice/bedrock interface. Various subsurface features observed in GPR transects at 200 MHz clearly showed up in TomoSAR sections as well, particularly firn bodies, crevasses, layer transitions, and bedrock reflection down to 50 m below the ice surface.