The Aircraft Integrated Meteorological Measuring System 20 Hz (AIMMS-20) has been used by the Hong Kong Observatory (HKO), China in data collection for tropical cyclone situations over the South China Sea and windshear and turbulence measurement at the Hong Kong International Airport (HKIA). This paper discusses possible methods for further enhancing the quality of the wind and temperature measurements from the system. For wind measurement, the enhancement methods include: error modelling of the accelerometer (e.g., bias offset and cross-axis rate sensitivity), global positioning system (GPS) phase lag consideration, better representation of the inertial measurement unit (IMU) velocity based on the GPS velocities and considering their location differences, consideration of the slower update of GPS velocity, and wing flexure. For temperature measurement, the methods include the consideration of the temperature sensor response and the sensor housing response. The results of typical flights using AIMMS-20 show that the accuracy of the wind and temperature data could be improved by 20%–30%. Though the discussion in the present paper is related mainly to a specific meteorological measuring system on a particular aircraft, the techniques so employed should be a useful reference for similar systems installed on other aircraft.

The buckling of thin-walled structures is presented using the 1D finite element based refined beam theory formulation that permits us to obtain N-order expansions for the three displacement fields over the section domain. These higher-order models are obtained in the framework of the Carrera unified formulation (CUF). CUF is a hierarchical formulation in which the refined models are obtained with no need for ad hoc formulations. Beam theories are obtained on the basis of Taylor-type and Lagrange polynomial expansions. Assessments of these theories have been carried out by their applications to studies related to the buckling of various beam structures, like the beams with square cross section, I-section, thin rectangular cross section, and annular beams. The results obtained match very well with those from commercial finite element software with a significantly less computational cost. Further, various types of modes like the bending modes, axial modes, torsional modes, and circumferential shell-type modes are observed.

This paper studies the excavation collapse at the Xianghu subway station on Hangzhou metro line 1. The objective is to present an overview of this case study and discuss the cause of the failure. Through field investigation and preliminary analysis, the reasons for the excavation collapse were the misuse of the soil parameters, over excavation, incorrect installation of steel struts, invalid monitoring data, and inadequate ground improvement. Finally, a small strain constitutive model was used for further analysis. In order to estimate damage efficiently, the orthogonal array (OA) was introduced for screening the key factor in the numerical experiments. Six estimated indexes including deformations and internal forces of the excavation were taken, and the effectiveness of four factors which may cause the collapse was evaluated. Through numerical experiments and interaction analysis, it is found that the deformation and internal force can be well controlled by jet grouting of the subsoil under the final cutting surface, but increasing the improvement ratio of the jet grouting cannot help optimize the excavation behavior efficiently, and without jet grouting and the fourth level struts, the deformation and internal force of the excavation in this case will far surpass the allowable value.

An exact analytical solution is obtained for convective heat transfer in straight ducts with rectangular cross-sections for the first time. This solution is valid for both H1 and H2 boundary conditions, which are related to fully developed convective heat transfer under constant heat flux at the duct walls. The separation of variables method and various other mathematical techniques are used to find the closed form of the temperature distribution. The local and mean Nusselt numbers are also obtained as functions of the aspect ratio. A new physical constraint is presented to solve the Neumann problem in non-dimensional analysis for the H2 boundary conditions. This is one of the major innovations of the current study. The analytical results indicate a singularity occurs at a critical aspect ratio of 2.4912 when calculating the local and mean Nusselt numbers.

Locating distribution centers optimally is a crucial and systematic task for decision-makers. Optimally located distribution centers can significantly improve the logistics system’s efficiency and reduce its operational costs. However, it is not an easy task to optimize distribution center locations and previous studies focused primarily on location optimization of a single distribution center. With growing logistics demands, multiple distribution centers become necessary to meet customers’ requirements, but few studies have tackled the multiple distribution center locations (MDCLs) problem. This paper presents a comprehensive algorithm to address the MDCLs problem. Fuzzy integration and clustering approach using the improved axiomatic fuzzy set (AFS) theory is developed for location clustering based on multiple hierarchical evaluation criteria. Then, technique for order preference by similarity to ideal solution (TOPSIS) is applied for evaluating and selecting the best candidate for each cluster. Sensitivity analysis is also conducted to assess the influence of each criterion in the location planning decision procedure. Results from a case study in Guiyang, China, reveals that the proposed approach developed in this study outperforms other similar algorithms for MDCLs selection. This new method may easily be extended to address location planning of other types of facilities, including hospitals, fire stations and schools.