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El Niño–Southern Oscillation (ENSO) is an important but not the only source of interannual variability over the Indo–western Pacific. Non-ENSO forced variability in the region has received recent attention because of the implications for rainy-season prediction. Using a 35-member CESM1 Large Ensemble (CESM-LE) and 30 CMIP6 models, this study shows that the ensemble means project intensified interannual variability for precipitation, low-level winds, and sea level pressure under global warming, associated with the enhanced large-scale anomalous anticyclone (AAC) over the tropical northwestern (NW) Pacific after the ENSO signal is removed. A decomposition based on the column water vapor budget reveals that enhanced precipitation variability is due to the increased background specific humidity. The resultant anomalous diabatic heating intensifies the AAC, which further strengthens the precipitation anomalies. Over the tropical NW Pacific, the wind-induced evaporative cooling on the southeastern flank of the AAC is countered by the increased shortwave radiation due to the strengthened precipitation reduction. Tropospheric temperature anomalies in the ensemble means show no significant change, suggesting no apparent change of the interbasin positive feedback between the AAC and northern Indian Ocean SST. Intermodel analysis based on CMIP6 reveals that models with a larger increase in ENSO-unrelated precipitation variability over the NW Pacific are associated with stronger background warming in the eastern equatorial Pacific, due to the modulated Walker and Hadley circulations.

The relationships between the seasonal mean storm-track anomalies and sea surface temperature anomalies (SSTAs) in the midlatitude Southern Hemisphere (SH) on the decadal time scale are investigated using the lagged maximum covariance analysis (MCA). It shows that the coupling between storm-track anomalies and SSTAs is most prominent in austral summer (January–March, JFM). Firstly, large cold SSTAs in the western South Indian Ocean (SIO), corresponding to the strengthened SST front on the equator side, substantially intensify the storm-track activity manifested by the increased low-level poleward transient eddy heat flux over the entire SH. The coherent intensification of the atmospheric baroclinicity and the subtropical jet associated with such strengthened SST front provides baroclinic energy for the growth of synoptic eddies. Further, the intensified storm-track activity induces large cold SSTAs in the South Atlantic (SA), the SIO and the subtropical South Pacific (SP), primarily via anomalous net surface heat fluxes. The mean SST advection by the anomalous Ekman current also contributes to the cold SSTAs in the SA, which is related to the anomalous westerlies induced by the anomalous storm-track activity.

Tropical precipitation change under global warming varies with season. The present study investigates the characteristics and cause of the seasonality in rainfall change. Diagnostically, tropical precipitation change is decomposed into thermodynamic and dynamic components. The thermodynamic component represents the wet-get-wetter effect and its seasonality is due mostly to that in the mean vertical velocity, especially in the monsoon regions. The dynamic component includes the warmer-get-wetter effect due to the spatial variations in sea surface temperature (SST) warming, while the seasonality is due to that of the climatological SST and can be largely reproduced by an atmospheric model forced with the monthly climatological SST plus the annual-mean SST warming pattern. In the eastern equatorial Pacific where the SST warming is locally enhanced; for example, rainfall increases only during the March–May season when the climatological SST is high enough for deep convection. To the extent that the seasonality of tropical precipitation change over oceans arises mostly from that of the climatological SST, the results support the notion that reducing model biases in climatology improves regional rainfall projections.

Regional ocean–atmospheric interactions in the summer tropical Indo–northwest Pacific region are investigated using a tropical Pacific Ocean–global atmosphere pacemaker experiment with a coupled ocean–atmospheric model (cPOGA) and a parallel atmosphere model simulation (aPOGA) forced with sea surface temperature (SST) variations from cPOGA. Whereas the ensemble mean features pronounced influences of El Niño–Southern Oscillation (ENSO), the ensemble spread represents internal variability unrelated to ENSO. By comparing the aPOGA and cPOGA, this study examines the effect of the ocean–atmosphere coupling on the ENSO-unrelated variability. In boreal summer, ocean–atmosphere coupling induces local positive feedback to enhance the variance and persistence of the sea level pressure and rainfall variability over the northwest Pacific and likewise induces local negative feedback to suppress the variance and persistence of the sea level pressure and rainfall variability over the north Indian Ocean. Anomalous surface heat fluxes induced by internal atmosphere variability cause SST to change, and SST anomalies feed back onto the atmosphere through atmospheric convection. The local feedback is sensitive to the background winds: positive under the mean easterlies and negative under the mean westerlies. In addition, north Indian Ocean SST anomalies reinforce the low-level anomalous circulation over the northwest Pacific through atmospheric Kelvin waves. This interbasin interaction, along with the local feedback, strengthens both the variance and persistence of atmospheric variability over the northwest Pacific. The response of the regional Indo–northwest Pacific mode to ENSO and influences on the Asian summer monsoon are discussed.

El Niño–Southern Oscillation (ENSO) peaks in boreal winter but its impact on Indo-western Pacific climate persists for another two seasons. Key ocean–atmosphere interaction processes for the ENSO effect are investigated using the Pacific Ocean–Global Atmosphere (POGA) experiment with a coupled general circulation model, where tropical Pacific sea surface temperature (SST) anomalies are restored to follow observations while the atmosphere and oceans are fully coupled elsewhere. The POGA shows skills in simulating the ENSO-forced warming of the tropical Indian Ocean and an anomalous anticyclonic circulation pattern over the northwestern tropical Pacific in the post–El Niño spring and summer. The 10-member POGA ensemble allows decomposing Indo-western Pacific variability into the ENSO forced and ENSO-unrelated (internal) components. Internal variability is comparable to the ENSO forcing in magnitude and independent of ENSO amplitude and phase. Random internal variability causes apparent decadal modulations of ENSO correlations over the Indo-western Pacific, which are high during epochs of high ENSO variance. This is broadly consistent with instrumental observations over the past 130 years as documented in recent studies. Internal variability features a sea level pressure pattern that extends into the north Indian Ocean and is associated with coherent SST anomalies from the Arabian Sea to the western Pacific, suggestive of ocean–atmosphere coupling.

The impact of internal tropical Pacific variability on global mean surface temperature (GMST) is quantified using a multimodel ensemble. A tropical Pacific index (TPI) is defined to track tropical Pacific sea surface temperature (SST) variability. The simulated GMST is highly correlated with TPI on the interannual time scale but this correlation weakens on the decadal time scale. The time-scale dependency is such that the GMST regression equation derived from the observations, which are dominated by interannual variability, would underestimate the magnitude of decadal GMST response to tropical Pacific variability. The surface air temperature response to tropical Pacific variability is strong in the tropics but weakens in the extratropics. The regression coefficient of GMST against TPI shows considerable intermodel variations, primarily because of differences in high latitudes. The results have important implications for the planned intercomparison of pacemaker experiments that force Pacific variability to follow the observed evolution. The model dependency of the GMST regression suggests that in pacemaker experiments—model performance in simulating the recent “slowdown” in global warming—will vary substantially among models. It also highlights the need to develop observational constraints and to quantify the TPI effect on the decadal variability of GMST. Compared to GMST, the correlation between global mean tropospheric temperature and TPI is high on both interannual and decadal time scales because of a common structure in the tropical tropospheric temperature response that is upward amplified and meridionally broad.

Effect of Laves phase formation on mechanical properties in a pressurized T-junction of P91 steel pipe at 849 K for 58,000 h with 25.65 MPa vapor pressure was studied. Thermodynamic calculations had been performed by using the software Thermo-Calc to study the phase at equilibrium state. Counter plot of von Mises stress in the pipe during service life was calculated by finite element analysis to study the effect of the operated stress distribution on the evolution of Laves phase. The change in the microstructure and mechanical properties in the sites with different stress was also studied. The results indicated that the formation of Laves phase in P91 steel was a thermodynamically possible process due to enrichment of Mo and depletion of C adjacent to M 23C6 particles or along martensite lath and packet boundaries. The formation of Laves phase had a detrimental influence on the mechanical properties in P91 steel. The mean size of Laves phase would be significantly increased with increasing operated stress, leading to a reduction in tensile properties and impact energy. In particular, crack initiation energy and crack growth energy during impact test rapidly decreased with increasing the mean size and volume fraction of Laves phase.

The camera shell is analyzed by using Finit Element Method (FEM) to judge reliability of the structure. Static structural and explicit dynamics analysis are conducted. The results provide valuable reference for the structural optimization design. Three schemes for injection mold are developed. Injection moulding process of the shell is simulated by applying Moldflow. The volumetric shrinkage, shrink mark index, total deformation, fill time and clamping force are analyzed. The results show that combining Moldflow with FEM method can not only shorten the construction period, but also ensure the molding quality.

Nowadays, customer has more and more requirements of quick product updating. On the opposition side, casting need a long lead time for tooling prepare and qualify. And a necessary test for casting is need. Whether a new casting design or existing casting product revised will take 16 weeks with tradition process. A new method raised in this text can help solute these problems. It calls Rapid & flexible process loop including CAD, CAE and RP. A better cost and time saving can be achieved via it.

The components of sheet metal FMS are abstracted corresponding eM-Plant object, the sheet metal FMS’s automatic guided vehicle system and parts management system are built in eM-Plant. Adjusting the system parameters in the model, several simulations obtained an ideal simulation result. These research show that, using eM-Plant software to build model and simulate for sheet metal FMS can save time, improve simulation result of sheet metal FMS.

Warpage is a crucial factor to accuracy of sintering part in selective laser sintering (SLS) process. In this paper, The influence of process parameters on warpage when sintering polystyrene(PS) materials in SLS are investigated. The laser power, scanning speed, hatch spacing, layer thickness as well as temperature of powder are considered as the main process parameters. The results showed that warpage increases with the increase of hatch space. Contary to it, warpage decreases with the increase of laser power. Warpage decreases with the increase of layer thickness between 0.16~0.18mm and changes little with increase of the thickness. Warpage increases along with the increase of scanning speed but decreases when the speed is over about 2000mm/s. When the temperature changes between 82°C-86°C, warpage decreases little with the increase of temperature. But further increase of temperature leads to warpage decreasing sharply when the temperature changes between 86°C-90°C.

Polymer nanocomposites based on organically modified layered silicates, e.g., organic-montmorillonite (org-MMT), exhibit attractive properties, such as increased mechanical properties, reduced gas and liquid permeability, improved heat, solvent and UV resistance, greater dimensional stability at elevated temperature, improved optical and electrical properties, and enhanced flame retardant properties [1–4]. Three different methods, in situ polymerization, polymer intercalation from solution, and direct polymer melt intercalation, have been used to synthesize layered silicate-based polymer nanocomposites [5]. The third method would greatly expand the commercial opportunities for nanocomposite technology because of its low cost, high productivity and compatibility with current polymer processing techniques [6]. In recent years, some researchers employed the direct melt intercalation technique to prepare the polymer nanocomposites [6–12]. However, these studies used a laboratoryscale twin screw extruder or internal mixer to yield nanocomposites and then investigated the microstructure and properties of only the as-extruded pellets or samples. Recently, the authors [13] used an industrial-scale extrusion blow molding machine to make packaging bottles from polypropylene (PP) or high-density polyethylene (HDPE)/org-MMT nanocomposites prepared by using a twin screw extruder. The changes of the microstructure of nanocomposites occurring after processing using a single screw extruder were investigated preliminarily. In this work, PP/org-MMT nanocomposites were prepared by direct melt intercalation using an industrial-scale co-rotating twin screw extruder. The as-extruded pellets were then extruded into ribbons by using an industrial-scale single screw extruder. The major focus was on the effects of mixing type of the screw on the microstructure changes of polymer nanocomposites. The microstructure of specimens was investigated by wide-angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM). The org-MMT (Fenghong Clay Co.) was supplied as particles with an average size of 25 μm. The polymer matrix was isotactic PP homopolymer (F401