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For flow around elongated bluff bodies, flow separations would occur over both leading and trailing edges. Interactions between these two separations can be established through acoustic perturbation. In this paper, the flow and the acoustic fields of a D-shaped bluff body (length-to-height ratio L/H = 3.64) are investigated at height-based Reynolds number Re = 23,000 by experimental and numerical methods. The purpose of this paper is to study the acoustic feedback in the interaction of these two separated flows.

The flow field is measured by particle image velocimetry, hotwire velocimetry and surface oil flow visualization. The acoustic field is modeled in two dimensions by direct aeroacoustic simulation, which solves the compressible Navier–Stokes equations. The simulation is validated against the experimental results.

Separations occur at both the leading and the trailing edges. The leading-edge separation point and the reattaching flow oscillate in accordance with the trailing-edge vortex shedding. Significant pressure waves are generated at the trailing edge by the vortex shedding rather than the leading-edge vortices. Pressure-based cross-correlation analysis is conducted to clarify the effect of the pressure waves on the leading-edge flow structures.

The understanding of interactions of separated flows over elongated bluff bodies helps to predict aerodynamic drag, structural vibration and noise in engineering applications, such as the aerodynamics of buildings, bridges and road vehicles.

This paper clarifies the influence of acoustic perturbations in the interaction of separated flows over a D-shaped bluff body. The contribution of the leading- and the trailing-edge vortex in generating acoustic perturbations is investigated as well.

In order to evaluate the rheological properties of asphalt more comprehensively and effectively, and to explore and discuss the practicability of relevant models in the evaluation of the rheological properties of asphalt.

Based on the rheological and viscoelastic theories, temperature scanning, frequency scanning and multiple stress creep recovery (MSCR) tests of different modified asphalt were carried out by dynamic shear rheometer (DSR) to obtain relevant viscoelastic parameters and evaluate the high temperature properties of different modified asphalt. Based on the time-temperature equivalence principle, the main curve was constructed to study the viscoelastic properties of asphalt in a wider frequency domain. The main curve was fitted with the CAM model, and the rheological properties of different modified asphalt were evaluated through the analysis of model parameters. The creep stiffness and creep velocity of different modified asphalt were obtained through the rheological test of bending beam (BBR), and the low-temperature performance of different modified asphalt was analyzed by using Burgers model to fit the creep compliance.

The results show that the high temperature rheological properties of several modified asphalt studied in the test are ranked from best to worst as follows: PE modified asphalt > SBS modified asphalt > SBR modified asphalt. Short-term aging can improve the high temperature performance of asphalt, and different types of modifiers can promote or inhibit this improvement effect. Based on BBR test and Burgers model fitting analysis, SBR modified asphalt has the best low temperature performance, followed by SBS modified asphalt, while PE modified asphalt has poor low temperature performance, so it is not suitable to be used as road material in low temperature area.

Combined with effective evaluation methods, the rheological properties of asphalt at different temperatures and angles were systematically evaluated, and the evolution of rheological properties of asphalt characterized by model parameters was further analyzed by advanced model simulation.

Public crisis often generates new knowledge that should be incorporated into a government’s macro-control to ensure the relief supply. From the perspective of public crisis knowledge management, the Chinese system of Government relief supplies can be considered as a special case of the knowledge system. This paper aims to investigate the supply and production mechanism of relief goods and explore the advantages of the Chinese system when a sudden public crisis occurs.

Under the Chinese system, the authors construct a relief supply chain model consisting of the Chinese Government, one manufacturer and one supplier, where the supplier has no capital constraints. Given the demand for relief goods, the government purchases from the manufacturer with a guide price. Then, the manufacturer decides on its order quantity and offers a wholesale price to the supplier. The supplier has a random capacity and decides on the level of knowledge acquisition to improve its capacity.

The authors first obtain the analytical solution for the manufacturer to motivate a high level of knowledge acquisition from the supplier. Specifically, the manufacturer’s optimal order quantity is equal to the demand and the optimal wholesale price has a cost-plus form that reimburses the supplier for its production cost and knowledge-acquisition cost. Next, the authors derive the optimal guide price for the government, which should be set to subsidize the manufacturer with a proportion of the sourcing cost. Finally, the authors compare the Chinese system with the market mechanism where the supplier has capital constraints and confirm that the Chinese system is more beneficial to both the manufacturer and the government.

Quantitative research on the Chinese system of Government relief supplies is difficult to be conducted. This paper provides feasible and practical methods to quantify the benefits of the Chinese system. The results reveal that the Chinese system is an effective mechanism of public crisis knowledge management, which can be helpful to the government’s policy-making in practice.

Happiness is an important mental emotion and yet becoming a major health concern nowadays. For this reason, better recognizing the objective understanding of how humans respond to event-related observations in their daily lives is especially important.

This paper uses non-intrusive technology (hyperspectral imaging [HSI]) for happiness recognition. Experimental setup is conducted for data collection in real-life environments where observers are showing spontaneous expressions of emotions (calm, happy, unhappy: angry) during the experimental process. Based on facial imaging captured from HSI, this work collects our emotional database defined as SWU Happiness DB and studies whether the physiological signal (i.e. tissue oxygen saturation [StO2], obtained by an optical absorption model) can be used to recognize observer happiness automatically. It proposes a novel method to capture local dynamic patterns (LDP) in facial regions, introducing local variations in facial StO₂ to fully use physiological characteristics with regard to hyperspectral patterns. Further, it applies a linear discriminant analysis-based support vector machine to recognize happiness patterns.

The results show that the best classification accuracy is 97.89 per cent, objectively demonstrating a feasible application of LDP features on happiness recognition.

This paper proposes a novel feature (i.e. LDP) to represent the local variations in facial StO₂ for modeling the active happiness. It provides a possible extension to the promising practical application.

Nanotechnology has been able to bind to a wide range of functional textiles in recently. This paper aims to modify graphene oxide (GO) by grafting dimethyl phosphite and perfluorohexyl iodine. It was applied to cotton to obtain a flame-retardant, water-repellent and ultraviolet-resistant multifunctional fabric.

The GO-multi was synthesized by grafted dimethyl phosphite and perfluorohexyl chain and applied to cotton by the dipping-drying method. The surface chemistry of functionalized GO was characterized by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The thermal stability of the fabric was characterized by thermogravimetric analysis (TGA). The combustion properties were evaluated using a microscale combustion calorimeter, match test and TGA. Hydrophobicity of film and fabric surface was characterized by static contact angle, and the UV resistance of the fabric was represented by the ultroviolet procetion factor (UPF) value.

Dimethyl phosphite and perfluorohexyl chains were grafted on the surface of GO successively. In the match test, the GO-multi/cotton kept the original outline of the fabric. According to the micro-scale combustion calorimetry (MCC) data, the value of PHRR and THR of GO-multi/cotton was about 45 per cent lower than that of untreated cotton fabric. It was found from the field-emission scanning electron microscopy (SEM) pictures that the residue of GO-multi/ cotton burned by the match method was more compact and the graphene lamellar structure remained more complete. The hydrophobic effect of GO-multi/cotton was improved compared to untreated cotton, but not better than the fabric treated by the perfluorohexyl chain-grafted GO. The UPF value of GO-multi/cotton reached 253, which indicated that the anti-ultraviolet performance of GO-multi was greatly improved after it was deposited on the cotton fabric.

Although the hydrophobic effect was much higher than that of untreated cotton fabric, its hydrophobic effect was not satisfied, which may be due to the fact that the content of F element content was low. So, it is still needed to explore the modifying method to increase the functional component amount on the GO nanosheet.

This modifying method can be used in any of multifunctional textile preparation process. The hydrophobic and flame-retardant cotton fabric revealed a sample for use in outdoor sports such as clothes and tents.

To meet the needs of multifunctional cotton fabrics, the modification of GO with dimethyl phosphite and perfluorohexyl iodine has not been reported. The modified fabric has flame-retardant, UV-resistant and hydrophobic properties.

In order to give full play to the function of noise reduction of asphalt pavement, it is necessary to understand its internal sound absorption mechanism. Therefore, the purpose of this study is to establish a micro model of the pore structure of asphalt mixture with the help of finite element method (FEM), discuss the noise reduction mechanism of asphalt pavement from the micro perspective and analyze and evaluate the noise attenuation law of the pore structure.

The FEM was used to establish the microscopic model of the pore structure of asphalt mixture. Based on the principle of acoustics, the noise reduction characteristics of asphalt pavement were simulated. The influence of gradation and pore characteristics on the noise reduction performance of asphalt pavement was analyzed.

The results show that the open graded friction course-13 (OGFC-13) has excellent performance in noise reduction. The resonant sound absorption structure composed of its large porosity can effectively reduce the pavement noise. For asphalt concrete-13 (AC-13) and stone matrix asphalt-13 (SMA-13), the less resonant sound absorption structure makes them have poor sound absorption effect. In addition, the variation rules of noise transmission loss (TL) curve and sound absorption coefficient curve of three graded asphalt mixtures were obtained. At the same time, the peak noise reduction values of OGFC-13, AC-13 and SMA-13 were obtained, which were 650Hz, 1000Hz and 800Hz, respectively.

The results show that the simulation results can well reflect and express the experimental results. This will provide a reference for further exploring the sound absorption mechanism and its variation rule of porous asphalt pavement. It also has some positive significance for the application of low noise asphalt pavement.

Industrial Internet Platform (IIP) integrates various new information technologies and forms an ecosystem around the platform. It promotes the optimization of resource elements and the collaboration of industrial chains, driving traditional enterprises towards comprehensive Digital Transformation (DT). This research explores the mechanisms through which the Industrial Internet Platform enables the digital development of enterprises.

This study constructs an Industrial Internet Platform Ecosystem (IIPE) from an ecosystem perspective. Later, a systematic literature review was used to design a specific path for IIPE to enable enterprises' DT from the perspective of basic activities and organizational structure.

The results indicate that in IIPE there is a hierarchical structure in the enabling mechanism of IIP. Firstly, the IIPE enhances the digital capabilities of enterprises through the foundational activities of DT. Secondly, the IIPE promotes the adjustment in enterprise structure and strategic orientation for adapting to the DT.

More and more enterprises enter the IIPE and grow together in the ecosystem. As a result, the overall level of digitalization of the industry can be enhanced and all enterprises realize the expected benefits of DT.

Existing research recognized the role of IIP in enterprise management or production processes, but the DT of enterprises is not a single aspect. This research elaborates the mechanism of comprehensive DT of enterprises from the perspective of ecosystems and discovers specific paths for DT.

The purpose of this paper is to propose a method that can calculate the transportation infrastructure network service capacity enhancement given by planned transportation infrastructure projects construction. Managers can sequence projects more rationally to maximize the construction effectiveness of infrastructure investments.

This paper designed a computational network simulation software to generate topological networks based on established rules. Based on the topological networks, the software simulated the movement path of users and calculated the average travel time. This software allows the adjustment of parameters to suit different research objectives. The average travel time is used as an evaluation index to determine the most appropriate construction sequence.

In this paper, the transportation infrastructure network of Sichuan Province in China was used to demonstrate this software. The average travel time of the existing transportation network in Sichuan Province was calculated as 211 min using this software. The high-speed railways from Leshan to Xichang and from Xichang to Yibin had the greatest influence on shortening the average travel time. This paper also measured the changes in the average travel time under two strategies: shortening the maximum and minimum priorities. All the transportation network optimisation plans for Sichuan Province will be somewhere between these two strategies.

The contribution of this research are three aspects: First, a complex network analysis method that can take into account the differences of node elements is proposed. Second, it provides an effective tool for decision makers to plan transportation infrastructure construction. Third, the construction sequence of transportation infrastructure development plan can effect the infrastructure investment effectiveness.

In order to determine the range of medium temperature zone of road asphalt, it is hoped that the evolution of viscoelastic characteristics of road asphalt under medium temperature state can be deeply explored.

In this paper, the needle penetration test and temperature scanning test were designed for 90# and 70# bitumen as test materials, and the boundary of medium temperature zone of 90# and 70# bitumen was accurately determined by data analysis method. A mathematical model was established based on principal component analysis, and a comprehensive evaluation index was proposed to evaluate the evolution of temperature viscoelastic characteristics of road asphalt by means of standardization and rotational dimensionality reduction.

The test results show that the medium temperature zone of 90# asphalt is [−5 ± 1°C, 38 ± 1°C], and the medium temperature zone of 70# asphalt is [0 ± 1°C, 51 ± 1°C]. According to the viscoelastic response of road asphalt in the medium temperature zone, the medium temperature zone can be divided into three evolution stages: weak viscoelastic stage, viscoelastic equilibrium stage, strong viscoelastic weak stage. Analysis based on the intrinsic viscosity fillip target describing the various intrinsic viscoelastic index represents the viscoelastic properties of bitumen from different angles, and limitations inherent stick fillip for target put forward the integrated the inherent stick fillip mark information, as well as targeted and accurate evaluation of road asphalt temperature comprehensive evaluation indexes in the evolution of the viscoelastic properties of I_M-T. Finally, the temperature data of asphalt pavement in several representative regions of China are compared with the determined medium temperature region, and it is proved that the research on the evolution of viscoelastic characteristics of asphalt pavement under the medium temperature condition has important practical significance.

The boundary of medium temperature zone of 90# and 70# base asphalt was determined, and the viscoelastic characteristic evolution of road asphalt under medium temperature state was studied deeply. Aiming at the limitation of intrinsic viscoelastic index, a comprehensive evaluation index IM-T which not only integrates the information of intrinsic viscoelastic index but also can accurately evaluate the evolution of temperature viscoelastic characteristics in road asphalt is proposed.