Experimental investigation of the temperature fade in the cavitation zone of full journal bearings

This paper describes an experimental investigation with a rig for measuring the surface temperatures and pressures in single bore journal bearings. The test bearing was equipped with small bores, where the pressure was altered by means of a vacuum pump. The whole bearing arrangement can also be operated at different ambient pressures ranging from atmospheric down to −0.06 MPa. Oil temperatures at inlet and outlet are also measured. Experiments show a considerable drop in the temperature of oil undergoing a drop in pressure. The overall temperature level of the bearing system did not seem to affect the magnitude of the temperature drop. Experiments where the bearing system was operated at sub-ambient pressures revealed an increased temperature drop in the cavitation zone. Pressures higher than ambient were measured within the cavitation zone while the bearing was operated at sub-atmospheric pressure. The higher pressures are believed to be caused by evaporation of oil. It is therefore proposed that the temperature drop observed in the cavitation zone of journal bearings is primarily caused by evaporation of oil. However, isentropic decompression of the gases in the oil is also believed to play a role.     

Wind-driven rain as a boundary condition for HAM simulations: Analysis of simplified modelling approaches

While the numerical simulation of moisture transfer inside building components is currently undergoing standardisation, the modelling of the atmospheric boundary conditions has received far less attention.     

Microstructural characterization of Cu-poor Cu (In, Ga)Se2 surface layer

Grazing incidence X-ray diffraction (GIXRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX) are combined to investigate the microstructure and chemical composition of the surface layer in Cu(In, Ga)Se₂ (CIGS) thin films deposited using a three-stage co-evaporation process. According to the GIXRD and micro-region electron diffraction analyses, ordered defect chalcopyrite (ODC) structure does not exist in the surface layer and the surface and the bulk region of the CIGS film have the similar crystal structure. However, the results from the EDX data show that the compositional ratios of the Cu/(In + Ga) (Cu/III) have a gradient distribution across the whole surface layer. The surface layer shows a Cu-poor compositional characteristics and the Cu content increases gradually from the surface to the bulk of the material. The compositional depth profiles determined by XPS agree very well with the results of the EDX measurements. The thickness of the surface layer has been determined to be about 50-100 nm in consistence with that estimated from the compositional ratio of Cu/III. High density dislocations have been observed in the surface region of these samples by high resolution TEM analyses. Our results suggest that different compositions would induce different point defects in the surface layer.     

An empirical model for estimating evaporative hydrocarbon emissions from canister-equipped vehicles

An empirical model for the estimation of evaporative hydrocarbon emissions from canister-equipped vehicles has been developed from experimental data obtained from repeated tests on a single carbon canister. The model is able to predict canister adsorption and desorption behaviour under different loading and purging conditions and it calculates canister weight and breakthrough emissions for various experimental variables including temperature, mixture concentration and mass flow rate. The model enables the simulation of a full evaporative emission Sealed Housing for Evaporative Determination (SHED) test procedure taking into account vehicle-specific estimations of fuel vapour generation and permeation. Results from measurements conducted on a vehicle equipped with the same canister were used to calibrate the model. Model results were in good agreement with measured evaporative emissions from a number of vehicles.