Change of crack mode in rock cracking process under quasi-static and dynamic loadings

Author(s):  
Chunjiang Zou ◽  
Varun Maruvanchery ◽  
Xiaobao Zhao ◽  
Lei He
2018 ◽  
Vol 69 (10) ◽  
pp. 2633-2637
Author(s):  
Raluca Dragomir ◽  
Paul Rosca ◽  
Cristina Popa

The main objectives of the present paper are to adaptation the five-kinetic model of the catalytic cracking process and simulation the riser to predicts the FCC products yields when one of the major input variable of the process is change. The simulation and adaptation are based on the industrial data from Romanian refinery. The adaptation is realize using a computational method from Optimization Toolbox from Matlab programming language. The new model can be used for optimization and control of FCC riser.


2020 ◽  
Vol 1000 ◽  
pp. 257-264
Author(s):  
Bambang Heru Susanto ◽  
Joshua Raymond Valentino Siallagan

Bio-Jet could be produced by the synthesis of vegetable oil through the hydrodeoxygenation, decarboxylation, decarbonization, and catalytic cracking process. Physical characteristics, activities, and selectivity of the catalyst used will determine the rate, conversion, and yield of the reaction that being carried out. This study aims to compare and obtain the best characteristics of NiMoP/γ-Al2O3 catalysts synthesized using two types of preparation, impregnation and microwave polyol methods, which will be used for bio-jet production. The impregnation method takes more than 24 hours for catalyst preparation, while microwave polyols that use microwaves can synthesize catalysts faster. Both catalysts have almost the same loading on the weight of the catalyst, which in the microwave polyol method has a more dispersed promotor and active site, although the crystallinity level is deficient and tends to be amorphous compared to the impregnation method with high crystallinity. In bio-jet synthesis reaction with operating conditions of 5% catalyst loading by comparison to Coconut Oil, 400°C, and 15 bar, the conversion, yield, and selectivity of catalyst impregnation were 91.705%, 47.639%, and 84.511%, while microwave polyol catalysts were 90.296%, 42.752%, and 82.517%, respectively. In conclusion, microwave polyol provides a more effective and efficient preparation method.


2021 ◽  
Vol 278 ◽  
pp. 122419
Author(s):  
Zhangyu Wu ◽  
Jinhua Zhang ◽  
Qin Fang ◽  
Hongfa Yu ◽  
Ma Haiyan

2021 ◽  
pp. 147592172199474
Author(s):  
Bin Xu ◽  
Ye Zhao ◽  
Baichuan Deng ◽  
Yibang Du ◽  
Chen Wang ◽  
...  

Identification of nonlinear restoring force and dynamic loadings provides critical information for post-event damage diagnosis of structures. Due to high complexity and individuality of structural nonlinearities, it is difficult to provide an exact parametric mathematical model in advance to describe the nonlinear behavior of a structural member or a substructure under strong dynamic loadings in practice. Moreover, external dynamic loading applied to an engineering structure is usually unknown and only acceleration responses at limited degrees of freedom of the structure are available for identification. In this study, a nonparametric nonlinear restoring force and excitation identification approach combining the Legendre polynomial model and extended Kalman filter with unknown input is proposed using limited acceleration measurements fused with limited displacement measurements. Then, the performance of the proposed approach is first illustrated via numerical simulation with multi-degree-of-freedom frame structures equipped with magnetorheological dampers mimicking nonlinearity under direct dynamic excitation or base excitation using noise-polluted measurements. Finally, a dynamic experimental study on a four-story steel frame model equipped with a magnetorheological damper is carried out and dynamic response measurement is employed to validate the effectiveness of the proposed method by comparing the identified dynamic responses, nonlinear restoring force, and excitation force with the test measurements. The convergence and the effect of initial estimation errors of structural parameters on the final identification results are investigated. The effect of data fusion on improving the identification accuracy is also investigated.


Fuel ◽  
2021 ◽  
Vol 292 ◽  
pp. 120364
Author(s):  
Peipei Miao ◽  
Xiaolin Zhu ◽  
Yangling Guo ◽  
Jie Miao ◽  
Mengyun Yu ◽  
...  

1994 ◽  
Vol 153 (1) ◽  
pp. 57-69 ◽  
Author(s):  
Naoki Miura ◽  
Terutaka Fujioka ◽  
Koichi Kashima ◽  
Satoshi Kanno ◽  
Makoto Hayashi ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1440
Author(s):  
Pei-Yuan Lun ◽  
Xiao-Gang Zhang ◽  
Ce Jiang ◽  
Yi-Fei Ma ◽  
Lei Fu

The premature failure of reinforced concrete (RC) structures is significantly affected by chloride-induced corrosion of reinforcing steel. Although researchers have achieved many outstanding results in the structural capacity of RC structures in the past few decades, the topic of service life has gradually attracted researchers’ attention. In this work, based on the stress intensity, two models are developed to predict the threshold expansive pressure, corrosion rate and cover cracking time of the corrosion-induced cracking process for RC structures. Specifically, in the proposed models, both the influence of initial defects and modified corrosion current density are taken into account. The results given by these models are in a good agreement with practical experience and laboratory studies, and the influence of each parameter on cover cracking is analyzed. In addition, considering the uncertainty existing in the deterioration process of RC structures, a methodology based on the third-moment method in regard to the stochastic process is proposed, which is able to evaluate the cracking risk of RC structures quantitatively and predict their service life. This method provides a good means to solve relevant problems and can prolong the service life of concrete infrastructures subjected to corrosion by applying timely inspection and repairs.


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