NUMERICAL INVESTIGATION OF GLASS-FIBER REINFORCED PLASTIC MORTAR PIPES CULVERT RESPONSE TO HEAVY TRUCK LOADS

The main objective of this paper is to investigate the dynamic performance and behaviour of glass-fiber reinforced plastic (GRP) mortar pipes under heavy truck loads. According to the field conditions, a finite element dynamic analysis (FEDA) model of GRP pipe culverts was established. Modal analysis of the vibration system was carried out, and the main natural frequencies with 26.6Hz,32Hz,35.7Hz and corresponding mode shapes were obtained. On the basis of modal analysis, dynamic response of GRP pipe culverts under vehicle loads was simulated through random vibration. Based on the measured vibration velocity time histories, the modal and random vibration responses of the vibration system were analyzed. The results show that the spectral response value of pipeline to vehicle load decreases with the increase of buried depth. When the depth of GRP pipe culverts buried is greater than 0.8m, the influence of ground vehicle dynamic loads on the vibration of GRP pipe culverts cannot be taken into consideration. It can provide the basis for the design of GRP pipe culverts, especially under heavy loads

MECHANICAL BEHAVIOR OF COMPOSITIONS OF GLASS-FIBER REINFORCED PLASTIC MORTAR PIPES BASED ON THEIR FUNCTIONING

The experimental investigation on the mechanical parameters compositions of glass-fiber reinforced plastic mortar (GRPM) pipe is the basis of simulating and analyzing the mechanical characteristics of the complete structure of GRPM pipe. Due to the anisotropic material properties of GRPM pipe, the compressive property test is carried out, and the results show that the circumferential compressive strength(CCS) is 49.93Mpa, the axial compressive strength(ACS) is 40.79Mpa, the circumferential elastic modulus(CEM) is 4.84Gpa, and the axial elastic modulus(AEM) is 4.04Gpa. The difference between the CCS and ACS and EM is about 20%, as well as the CCS and EM are greater than the ACS and modulus of elasticity. Conclusions drawn from the tests provide an important basis for checking whether the materials meet the design requirements. &nbsp

Simulated Annealing-based Hybrid Genetic Algorithms

Abstract—Artificial neural networks are among the most effective learning methods currently known for certain types of problems. But BP training algorithm is based on the error gradient descent mechanism that the weight inevitably fall into the local minimum points. It is well known that simulated annealing (SA) and genetic algorithm (GA) are two global methods and can then be used to determine the optimal solution of NP-hard problem. In this paper, due to difficulty of obtaining the optimal solution in medium and large-scaled problems, a hybrid genetic algorithm (HGA) was also developed. The proposed HGA incorporates simulated annealing into a basic genetic algorithm that enables the algorithm to perform genetic search over the subspace of local optima. The two proposed solution methods were compared on Rosenbrock and Shaffer function global optimal problems, and computational results suggest that the HGA algorithm have good ability of solving the problem and the performance of HGA is very promising because it is able to find an optimal or near-optimal solution for the test problems. To evaluate the performance of the hybrid genetic algorithm-based neural network, BP neural network is also involved for a comparison purpose. The results compared with genetic algorithm-based indicated that this method was successful in evolving ANNs. Index Terms—BP neural network, genetic algorithms, hybrid genetic algorithms, simulated annealing, global optimal I

Multi-strategy Improved Seagull Optimization Algorithm

Abstract Aiming at the shortcomings of seagull optimization algorithm in the process of searching for optimization, such as slow convergence speed, low precision, easy falling into local optimal, and performance dependent on the selection of parameters, this paper proposes an improved gull optimization algorithm based on multi-strategy fusion based on the analysis of gull population characteristics. Firstly, L–C cascade chaotic mapping is used to initialize the population so that seagulls are more evenly distributed in the initial solution space. Secondly, to improve the algorithm’s global exploration ability in the early stage, the nonlinear convergence factor is incorporated to adjust the position of seagulls in the migration stage. At the same time, the group learning strategy was introduced after the population position update to improve the population quality and optimization accuracy further. Finally, in the late stage of the algorithm, the golden sine strategy of the Levy flight guidance mechanism is used to update the population position to improve the population’s diversity and enhance the local development ability of the algorithm in the late stage. To verify the optimization performance of the improved algorithm, CEC2017 and CEC2022 test suites are selected for simulation experiments, and box graphs are drawn. The test results show that the proposed algorithm has apparent convergence speed, accuracy, and stability advantages. The engineering case results demonstrate the proposed algorithm’s advantages in solving complex problems with unknown search spaces

Assessment of sustainable urban transport development based on entropy and unascertained measure

<div><p>To find a more effective method for the assessment of sustainable urban transport development, the comprehensive assessment model of sustainable urban transport development was established based on the unascertained measure. On the basis of considering the factors influencing urban transport development, the comprehensive assessment indexes were selected, including urban economical development, transport demand, environment quality and energy consumption, and the assessment system of sustainable urban transport development was proposed. In view of different influencing factors of urban transport development, the index weight was calculated through the entropy weight coefficient method. Qualitative and quantitative analyses were conducted according to the actual condition. Then, the grade was obtained by using the credible degree recognition criterion from which the urban transport development level can be determined. Finally, a comprehensive assessment method for urban transport development was introduced. The application practice showed that the method can be used reasonably and effectively for the comprehensive assessment of urban transport development.</p></div

The result of the comprehensive assessment.

<p>The result of the comprehensive assessment.</p

Understanding the chemistry during the preparation of Pd/SSZ-13 for the low-temperature NO adsorption: The role of NH4-SSZ-13 support

The chemistry during the preparation of Pd/SSZ-13, including impregnation and calcination process, was investigated, using Pd(NO3)2 as precursor and NH4-SSZ-13 as the support. Special attention was paid on analyzing the improvement effect of NH4-SSZ-13 support on Pd2+ ions dispersion. The Pd(NO3)2 precursor remained intact after impregnation and transformed to Pd(NH3)x2+ during calcination at 200−290 °C, and then converted to Pd2+ ions occupying the ion-exchange sites by oxidizing the NH3 ligands to N2 at 290−450 °C. The formation of Pd(NH3)x2+ intermediates is a critical factor for achieving high Pd2+ dispersion, probably due to the fact that NH3 ligands give the intermediates high mobility, facilitating their movement to the ion-exchange sites. The PdO formation might be related to the excessive reduction of Pd2+ sites to metallic Pd, when catalyzing the oxidation of NH3 ligands and the NH4+ on the Brønsted acid sites.Peer reviewe

Design of High-Performance and General-Purpose Satellite Management Unit Based on Rad-Hard Multi-Core SoCand Linux

Since deep space exploration tasks, such as space gravitational wave detection, put forward increasingly higher requirements for the satellite platform, the scale and complexity of the satellite management unit (SMU) software are also increasing, and the trend of intelligentization is showing. It is difficult for the traditional SMU based on single-core system on chip (SoC) to meet the various requirements brought by the above trends. This paper presents a high-performance general-purpose SMU design. Based on rad-hard multi-core SoC, we configure and tailor Linux, and design an SMU software architecture with three modes. It has the characteristics of high performance, high reliability, general purpose and scalability, which can meet the needs of the SMU of future complex satellites. Finally, through the application experiment in the background of the space gravitational wave detection project, the performance and application prospect of our proposed SMU are demonstrated

Insight into hydrothermal aging effect on deactivation of Pd/SSZ-13 as low-temperature NO adsorption catalyst: Effect of dealumination and Pd mobility

Pd/SSZ-13 samples with the same Pd loading (1 wt.%) but different Si/Al ratio (6 and 13) were hydrothermally aged at 800, 850, and 900 ºC, respectively. The Pd/SSZ-13 with a lower Si/Al ratio suffers a more severe deactivation. The Pd/SSZ-13 with a Si/Al ratio of 6 experiences structural damage due to dealumination, while the structure of the sample with a Si/Al ratio of 13 remains intact. The agglomeration of Pd 2+ ions to large PdO particles on the external surface of zeolite causes the deactivation. The Pd cations are mobile during aging. Besides dealumination, the Pd 2+ ions might be hydrolyzed and have a high mobility, which also results in the Pd 2+ ions agglomeration. The severe dealumination causes the deactivation after aging at 900 ºC. However, the Pd mobility might be the primary reason for the decline of NO adsorption capacity of Pd/SSZ-13 after aging at 800 and 850 °C.Peer reviewe

Adaptive Access Selection Algorithm for Large-Scale Satellite Networks Based on Dynamic Domain

The traditional satellite access selection algorithm, which is used in large-scale satellite networks, has some disadvantages, such as frequent link switching, high interrupt probability, and unable to adapt to a dynamic environment. According to the periodicity of the large-scale satellite network and the prior knowledge provided by acknowledgment packages, a dynamic domain-based adaptive access algorithm (DAA) is proposed in this paper. Firstly, this algorithm divides the large-scale satellite network into different domains according to the minimum elevation angle of the Earth station (ES) and the predictable characteristics of the trajectory of the satellite. Then, the ES selects the access satellites according to the relationship between the traffic volume and the satellites’ coverage time. Finally, the ES selects the backup access satellite based on the satellites’ coverage time, the traffic volume of the ES, satellite status provided by prior knowledge, and other information. When the access satellite cannot satisfy the communication demand, the ES adaptively switches the earth-satellite link to the backup access satellite. The ES first choice of access satellite does not require interaction with the satellites, reducing the consumption of communication resources. The selection strategy of backup access satellite and the concept of virtual destination address proposed in this paper can reduce the routing overhead after switching. Through theoretical analysis and simulation results in the StarLink constellation, it is proved that this paper improves the coverage time utilization of accessing satellites and reduces the switching probability compared with the traditional access algorithm, which is more suitable for ES to access large-scale satellite networks