The effects of journal misalignment on a journal bearing caused by an asymmetric rotor structure are presented in this study. A new model considering the asymmetric deflection is applied. Also, the thermo-hydrodynamic of the oil film in the journal bearing and straightforward elasticity theory are considered in the analysis. Based on the structure stiffness equivalent characteristic, a simple stepped shaft can reflect the entire complex structure model. The existing lubrication model, which does not consider this angle component, is not very precise for journal bearings. Film pressure, misalignment angle, velocity field, oil leakage, and temperature field were calculated and compared in the journal bearing analysis. The results indicate that bearing performances are greatly affected by misalignment caused by the asymmetric structure. A simple stepped shaft can effectively represent a misaligned journal bearing in a rotor-bearing system.

Disk burst accidents sometimes happen in aeroengines. To avoid tragic consequences, aeroengine casings must have sufficient containment capability. Experiments and simulations need to be conducted to study the impact, distortion, and perforation caused by disk burst and which may give important clues to potential failure mechanisms. This paper presents some containment tests of high-speed rotating disk fragments, in which the original disks were burst into three equal fragments within a predetermined rotating speed range. The failure modes of the containment casing varied significantly with the thickness of the containment casing. Shearing, tearing, tensile fracture, and large plastic stretching deformation occurred in a thin-walled containment casing, while a thick-walled casing could contain disk fragments and withstand large plastic deformation. Numerical simulations were carried out to study the impact process and failure modes further. Good agreement was found between the results of the simulations and the tests.

The differential evolution (DE) algorithm has been received increasing attention in terms of optimizing the design for the water distribution systems (WDSs). This paper aims to carry out a comprehensive performance comparison between the new emerged DE algorithm and the most popular algorithm—the genetic algorithm (GA). A total of six benchmark WDS case studies were used with the number of decision variables ranging from 8 to 454. A preliminary sensitivity analysis was performed to select the most effective parameter values for both algorithms to enable the fair comparison. It is observed from the results that the DE algorithm consistently outperforms the GA in terms of both efficiency and the solution quality for each case study. Additionally, the DE algorithm was also compared with the previously published optimization algorithms based on the results for those six case studies, indicating that the DE exhibits comparable performance with other algorithms. It can be concluded that the DE is a newly promising optimization algorithm in the design of WDSs.

Analyzing the service behavior of high dams and establishing early-warning systems for them have become increasingly important in ensuring their long-term service. Current analysis methods used to obtain safety monitoring data are suited only to single survey point data. Unreliable or even paradoxical results are inevitably obtained when processing large amounts of monitoring data, thereby causing difficulty in acquiring precise conclusions. Therefore, we have developed a new method based on multi-source information fusion for conducting a comprehensive analysis of prototype monitoring data of high dams. In addition, we propose the use of decision information entropy analysis for building a diagnosis and early-warning system for the long-term service of high dams. Data metrics reduction is achieved using information fusion at the data level. A Bayesian information fusion is then conducted at the decision level to obtain a comprehensive diagnosis. Early-warning outcomes can be released after sorting analysis results from multi-positions in the dam according to importance. A case study indicates that the new method can effectively handle large amounts of monitoring data from numerous survey points. It can likewise obtain precise real-time results and export comprehensive early-warning outcomes from multi-positions of high dams.

Elemental mercury capture on heat-treated activated carbon (TAC) was studied using a laboratory-scale fixed bed reactor. The capability of TAC to perform Hg⁰ capture under both N₂ and baseline gas atmospheres was studied and the effects of common acid gas constituents were evaluated individually to avoid complications resulting from the coexistence of multiple components. The results suggest that surface functional groups (SFGs) on activated carbon (AC) are vital to Hg⁰ capture in the absence of acid gases. Meanwhile, the presence of acid gas components coupled with defective graphitic lattices on TAC plays an important role in effective Hg⁰ capture. The presence of HCl, NO₂, and NO individually in basic gases markedly enhances Hg⁰ capture on TAC due to the heterogeneous oxidation of Hg⁰ on acidic sites created on the carbon surface and catalysis by the defective graphitic lattices on TAC. Similarly, the presence of SO₂ improves Hg⁰ capture by about 20%. This improvement likely results from the deposition of sulfur groups on the AC surface and oxidation of the elemental mercury by SO₂ due to catalysis on the carbon surface. Furthermore, O₂ exhibits a synergistic effect on Hg⁰ oxidation and capture when acid gases are present in the flue gases.

A multi-dimensional computational fluid dynamics (CFD) approach was proposed in this study aiming to calculate the transfer matrix of an engine exhaust muffler in the conditions with and without mean flow. The CFD model of the muffler with absorptive material defined as porous zone was calibrated with the measured noise reduction without mean flow, and was further employed to study the effect of the mean flow on the acoustic performance of the muffler. Furthermore, the exhaust acoustical source was derived from the calculated transfer matrices of six different additional acoustic loads obtained by the proposed CFD approach as well as the measured tail noise based on a multiload least squares method. Finally, the exhaust noise was predicted based on Thevenin’s theorem. The proposed CFD approach was suggested to be able to predict the acoustic performance of a complex muffler considering mean flow (without and with mean flow) and heat transfer, and provide reasonable results of the exhaust noise.

This paper presents an improved model for global sunshine duration estimation. The methodology incorporates geostationary satellite images by including snow cover information, sun and satellite angles and a trend correction factor for seasons, for the determination of cloud cover index. The effectiveness of the proposed methodology has been tested using Meteosat geostationary satellite images in the visible band with a temporal resolution of 1 h and spatial resolution of 2.5 km×2.5 km, for the Brue Catchment in the southwest of England. Validation results show a significant improvement in the estimation of global sunshine duration by the proposed method as compared to its predecessor (R² is improved from 0.68 to 0.83, root mean squared error (RMSE) from 2.37 h/d to 1.19 h/d and the mean biased error (MBE) from 0.21 h/d to 0.08 h/d). Further studies are needed to test this method in other parts of the world with different climate and geographical conditions.