Statistical Characteristics and Mechanistic Analysis of Suddenly Reversed Tropical Cyclones over the Western North Pacific Ocean

Based on best track data of tropical cyclones（TCs） from the Japan Meteorological Agency, the characteristics of suddenly reversed TCs（SRTCs）, which have turning angles usually approaching 180°, are statistically analyzed from 1949 to 2011 over the western North Pacific Ocean. The typical large-scale circulation patterns of SRTCs are investigated using reanalysis data and dynamical composite analysis. Results show that turnings mainly occur in low latitudes between 10°N and 20°N,and mainly west of 135°E. The majority of SRTCs reach their peak intensity at, or slightly before, the turning time and subsequently decrease at some variable rate. Specifically, SRTCs are divided into four types, each containing two groups（i.e.eight groups in total） in terms of the moving-direction changes. The moving speed of all SRTC types except the south–north type decreases to its lowest during the 24 h, corresponding to a significant reduction in the primary steering components.According to the analysis of the 13 typical flow patterns found in this study, we suggest that sudden track changes are caused by the reversal steering flow. The original balance of the background flow patterns are broken up by new systems, e.g. binary TCs or dispersion-induced anticyclones. Additionally, sudden track changes are often due to double ridge variations of the subtropical high or weakened/strengthened high pressure in the east and west, respectively.

Sensitivity and inverse analysis methods for parameter intervals

This paper proposes a sensitivity analysis method for engineering parameters using interval analyses.This method substantially extends the application of interval analysis method.In this scheme,parameter intervals and decision-making target intervals are determined using the interval analysis method.As an example,an inverse analysis method for uncertainty is presented.The intervals of unknown parameters can be obtained by sampling measured data.Even for limited measured data,robust results can also be obtained with the inverse analysis method,which can be intuitively evaluated by the uncertainty expressed in terms of an interval.For complex nonlinear problems,an iteratively optimized inverse analysis model is proposed.In a given set of loose parameter intervals,all the unknown parameter intervals that satisfy the measured information can be obtained by an iteratively optimized inverse analysis model.The influences of measured precisions and the number of parameters on the results of the inverse analysis are evaluated.Finally,the uniqueness of the interval inverse analysis method is discussed.

Phase transformation and crystal growth behavior of 8mol%(SmO1.5, GdO1.5, and YO1.5) stabilized ZrO2 powders

Nanocrystalline powders of ZrO_2–8mol%SmO1.5（8Sm SZ）, ZrO_2–8mol%GdO1.5（8Gd SZ）, and ZrO_2–8mol%YO1.5（8YSZ） were prepared by a simple reverse-coprecipitation technique. Differential thermal analysis/thermogravimetry（DTA/TG）, Fourier transform infrared spectroscopy（FTIR）, X-ray diffraction（XRD）, Raman spectroscopy, and high-resolution transmission electron microscopy（HRTEM） were used to study the phase transformation and crystal growth behavior. The DTA results showed that the ZrO_2 freeze-dried precipitates crystallized at 529, 465, and 467°C in the case of 8Sm SZ, 8Gd SZ, and 8YSZ, respectively. The XRD and Raman results confirmed the presence of tetragonal ZrO_2 when the dried precipitates were calcined in the temperature range from 600 to 1000°C for 2 h. The crystallite size increased with increasing calcination temperature. The activation energies were calculated as 12.39, 12.45, and 16.59 k J/mol for 8Sm SZ, 8Gd SZ, and 8YSZ respectively.

PDGI-BASED REGULAR SWEPT SURFACE EXTRACTION FROM POINT CLOUD

A principal direction Gaussian image （PDGI）-based algorithm is proposed to extract the regular swept surface from point cloud. Firstly, the PDGI of the regular swept surface is constructed from point cloud, then the bounding box of the Gaussian sphere is uniformly partitioned into a number of small cubes （3D grids） and the PDGI points on the Gaussian sphere are associated with the corresponding 3D grids. Secondly, cluster analysis technique is used to sort out a group of 3D grids containing more PDGI points among the 3D grids. By the connected-region growing algorithm, the congregation point or the great circle is detected from the 3D grids. Thus the translational direction is determined by the congregation point and the direction of the rotational axis is determined by the great circle. In addition, the positional point of the rotational axis is obtained by the intersection of all the projected normal lines of the rotational surface on the plane being perpendicular to the estimated direction of the rotational axis. Finally, a pattem search method is applied to optimize the translational direction and the rotational axis. Some experiments are used to illustrate the feasibility of the above algorithm.

Integration of nanoindentation and finite element method for interpretable tensile properties:A crossscale calculation method of uneven joints

Nanoindentation testing and its Reverse Analysis Method(RAM)show great potential in understanding the tensile properties of metallic alloys with various microstructures.Nevertheless,the tensile properties of heterogeneous materials such as nickel-based superalloy welded joints have not been well interpreted by combining the microstructures and nanoindentation results,due to their diverse and complex microscopic zones,which throws shade on the properties of separated zones in the material.Here we demonstrated a new method of implanting nanoindentation results into Finite Element Method(FEM)and applied the method to the welded joints with the zones of various microstructure features.The local properties are calculated by the nanoindentation data using RAM,and used as input of Finite Element(FE)simulation of an identical indentation process,to in turn verify the accuracy and reliability of the reverse model.The simulation results reveal that the global mechanical behaviors,such as Young's modulus,yield strength and strain hardening exponent,are related to the local properties to a great extent.Thus,the global properties can be verified by simulation straight after experiments,taking consideration of local properties and dimension parameters of different zones.It is shown that the maximum error between calculation of RAM and testing is within 5.1%in different zones,and the errors of maximum indentation depth and residual depth obtained by FE simulation are less than 2.4%,which indicates that the method provides a reliable prediction of mechanical properties of superalloy welded joints.

A Hybrid Set of Complexity Metrics for Large-Scale Object-Oriented Software Systems

Large-scale object-oriented（OO） software systems have recently been found to share global network characteristics such as small world and scale free,which go beyond the scope of traditional software measurement and assessment methodologies.To measure the complexity at various levels of granularity,namely graph,class（and object） and source code,we propose a hierarchical set of metrics in terms of coupling and cohesion-the most important characteristics of software,and analyze a sample of 12 open-source OO software systems to empirically validate the set.Experimental results of the correlations between cross-level metrics indicate that the graph measures of our set complement traditional software metrics well from the viewpoint of network thinking,and provide more effective information about fault-prone classes in practice.