Mass transport through the nanoporous medium is ubiquitous in nature and *** the macroscale transport phenomena which have been well understood by the theory of continuum mechanics,the relevant physics and mechanics o...
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Mass transport through the nanoporous medium is ubiquitous in nature and *** the macroscale transport phenomena which have been well understood by the theory of continuum mechanics,the relevant physics and mechanics on the nanoscale transport still remain *** developments in fabrication of slit-like nanocapillaries with precise dimensions and atomically smooth surfaces have promoted the fundamental research on the molecular transport under extreme *** this review,we summarized the contemporary progress in the study of confined molecular transport of water,ions and gases,based on both experiments and molecular dynamics *** liquid exhibits a pronounced layered structure that extends over several intermolecular distances from the solid surface,which has a substantial influence on static properties and transport behaviors under *** studies have also shown that those molecular details could provide some new understanding on the century-old classical theory in this field.
There are many multiphase flow phenomena in steam generators (SG) of nuclear power plants (NPPs) and the movement of droplets affects the separation efficiency of dryers in SG. And the most important factor affecting ...
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Pore structure design is an effective strategy to tailor the thermal isolation capability of thermal barrier coatings(TBCs).Pursuing optimal porosity is crucial to balance the requirements of thermal isolation and mec...
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Pore structure design is an effective strategy to tailor the thermal isolation capability of thermal barrier coatings(TBCs).Pursuing optimal porosity is crucial to balance the requirements of thermal isolation and mechanical reliability since the pore structure shields thermal heat transfer but increases mechanical *** this work,we investigate how thermal heat transfer couples with fracture propagation in porous TBCs by the using thermo-mechanical coupling phase field model for *** simulated results show that cracks induced by thermal shock favor deflection that is sometimes perpendicular to the direction of heat *** thermal conductivity degradation by the transverse cracks significantly impedes thermal heat transfer,leads to enhanced reduction of the effective thermal conductivity of TBCs,decreases the average thermal stress of the substrate,and thus decreases the risk of the crack penetrating into the *** numerical results demonstrate that the phase field method fully considering the thermo-mechanical interaction between cracks and pores can be a useful tool to improve the thermal isolation of porous TBCs under extreme thermal shock loadings through pore structure design.
To improve the path efficiency for dynamic obstacle avoidance algorithms of Pioneer robots, this paper proposes an approach to create deep deterministic policy gradient (DDPG) smart agents with recurrent neural networ...
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Osmotic pressure is vital to many physiological activities,such as cell proliferation,wound healing and disease ***,how cells interact with the extracellular matrix(ECM)when subjected to osmotic shock remains ***,we v...
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Osmotic pressure is vital to many physiological activities,such as cell proliferation,wound healing and disease ***,how cells interact with the extracellular matrix(ECM)when subjected to osmotic shock remains ***,we visualize the mechanical interactions between cells and the ECM during osmotic shock by quantifying the dynamic evolution of the cell traction *** show that both hypertonic and hypotonic shocks induce continuous and large changes in cell traction ***,the traction force varies with cell volume:the traction force increases as cells shrink and decreases as cells ***,the direction of the traction force is independent of cell volume changes and is always toward the center of the cell-substrate ***,we reveal a mechanical mechanism in which the change in cortical tension caused by osmotic shock leads to the variation in traction force,which suggests a simple method for measuring changes in cell cortical *** findings provide new insights into the mechanical force response of cells to the external environment and may provide a deeper understanding of how the ECM regulates cell structure and function.
Nuclear safety-class DCS realizes reactor safety protection function, which is directly related to the safe and stable operation of nuclear power plants, so its reliability should be analyzed and optimized. In this pa...
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Reinforcement learning(RL) has roots in dynamic programming and it is called adaptive/approximate dynamic programming(ADP) within the control community. This paper reviews recent developments in ADP along with RL and ...
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Reinforcement learning(RL) has roots in dynamic programming and it is called adaptive/approximate dynamic programming(ADP) within the control community. This paper reviews recent developments in ADP along with RL and its applications to various advanced control fields. First, the background of the development of ADP is described, emphasizing the significance of regulation and tracking control problems. Some effective offline and online algorithms for ADP/adaptive critic control are displayed, where the main results towards discrete-time systems and continuous-time systems are surveyed, ***, the research progress on adaptive critic control based on the event-triggered framework and under uncertain environment is discussed, respectively, where event-based design, robust stabilization, and game design are reviewed. Moreover, the extensions of ADP for addressing control problems under complex environment attract enormous attention. The ADP architecture is revisited under the perspective of data-driven and RL frameworks,showing how they promote ADP formulation ***, several typical control applications with respect to RL and ADP are summarized, particularly in the fields of wastewater treatment processes and power systems, followed by some general prospects for future research. Overall, the comprehensive survey on ADP and RL for advanced control applications has d emonstrated its remarkable potential within the artificial intelligence era. In addition, it also plays a vital role in promoting environmental protection and industrial intelligence.
With the continuous improvement of computer hardware capabilities, the one-step method in reactor physics has become one of the important research directions in recent two decades. OpenMOC is an open-source MOC code d...
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Accurate and reliable modeling and simulation is the key prerequisite for intelligent control technology research of nuclear power plant. For the nuclear steam supply system (NSSS) of small pressurized water reactor u...
Accurate and reliable modeling and simulation is the key prerequisite for intelligent control technology research of nuclear power plant. For the nuclear steam supply system (NSSS) of small pressurized water reactor under bi-stable steady state operation scheme, this paper firstly establishes the models of the core, regulator, steam generator and other components. Then, the nuclear steam supply system platform (NSSSP) of small pressurized water reactor is built based on Matlab/Simulink. Simulations are carried out to analyze the normal operation transient and load rejection transient in the water supply flow control mode. The accuracy and reliability of NSSSP are verified to beconsistent with the commercial program RETRAN.
reactorsystem modeling is the premise of reactor control systemdesign. The common commercial thermal and hydraulic analysis programs like RELAP5, RETRAN have complex structure and slow operational speed, which are n...
reactorsystem modeling is the premise of reactor control systemdesign. The common commercial thermal and hydraulic analysis programs like RELAP5, RETRAN have complex structure and slow operational speed, which are not conductive to the transplantation and improvement of reactorsystem. In order to realize the rapid development of reactor control system, this paper carries out the mechanism modeling of the reactorsystem in Matlab/Simulink, and then introduce BP neural network to establish the hybrid model, which improves the modeling accuracy to support the design of reactorsystem. For small pressurized water reactor, we firstly take analytical modeling method to build the core mechanism model and its state space model through three conservation principles and the operating mechanism of core. Based on analyses, we can conclude that the parameter error and structural error of the mechanism model is caused by the assumption and simplification during modeling, and choose the parameter with the most influence (the feedback coefficient of the coolant temperature) as the corrected parameter in the BP neural-based hybrid modeling process. After that, according to the dual constant operation scheme of small pressurized water reactors, and the gradient descent method of BP network, the hybrid model of core is built and the parameter error and structure error of the mechanism modeling are corrected online. The simulation results show that the proposed hybrid modeling method can accurately simulate the reactor operate state. Thus, the proposed hybrid model is accurate and effective.
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