In this paper, we develop a graph neural network (GNN)-assisted bilinear inference approach to enhance the receiver performance of the MIMO system through message passing-based joint channel estimation and data detect...
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In this paper,the evaluations of metal ablation processes under high temperature,i.e.,the Al plate ablated by a laser and a heat carrier and the reactor pressure vessel ablated by a core melt,are studied by a novel pe...
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In this paper,the evaluations of metal ablation processes under high temperature,i.e.,the Al plate ablated by a laser and a heat carrier and the reactor pressure vessel ablated by a core melt,are studied by a novel peridynamic *** all,the peridynamic formulation for the heat conduction problem is obtained by Taylor’s expansion ***,a simple and efficient moving boundary model in the peridynamic framework is proposed to handle the variable geometries,in which the ablated states of material points are described by an additional scalar ***,due to the automatic non-interpenetration properties of peridynamic method,a contact algorithm is established to determine the contact relationship between the ablated system and the additional heat *** addition,the corresponding computational procedure is listed in ***,several numerical examples are carried out and the results verify the validity and accuracy of the present method.
A numerical method to predict the bursting strength of filament wound composite rocket motor case is proposed here. This method can evaluate the longitudinal stress evolution of each composite layer as impregnated fil...
A numerical method to predict the bursting strength of filament wound composite rocket motor case is proposed here. This method can evaluate the longitudinal stress evolution of each composite layer as impregnated filaments with fiber tension are wound layer by layer, and consider the effects of accumulated stress and deformation during filament winding on the bursting strength of composite case. Taking ?520 mm composite cases as a case study, the filament-winding-processinduced stress and deformation as well as progressive damage behavior are numerically predicted,followed by a comparison with experimental results. The numerical results show that the predicted bursting pressures for composite cases manufactured on the mandrels with and without a flexible component are 14.20 MPa and 21.40 MPa, respectively. These values exhibit slight deviation from the measured pressures of 13.50 MPa and 21.57 MPa. Moreover, the predicted damage locations,situated respectively in the dome and cylinder, agree well with the experimental observation. These observations indicate that use of flexible component reduces the load-bearing capacity of the ***, it validates the reliability and accuracy of the proposed numerical method in predicting the bursting strength of composite cases.
The heat pipe cooled reactor (HPR) offers high safety and compactness for space applications. This study experimentally investigates the coupled transient thermal behavior of the primary sodium heat pipe, thermoelectr...
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This article proposes a new multi-level inverter (MLI) based on flying capacitor inverter (FCI), with focused on high-precision positioning control for a voice coil motor (VCM). Multi-level inverters (MLIs) have the c...
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ISBN:
(数字)9798331533892
ISBN:
(纸本)9798331533908
This article proposes a new multi-level inverter (MLI) based on flying capacitor inverter (FCI), with focused on high-precision positioning control for a voice coil motor (VCM). Multi-level inverters (MLIs) have the characteristic that increasing the number of output voltage levels reduces the output voltage error. However, as the number of levels increases, the number of circuit elements increases, and the circuit becomes more complex. In addition, the output voltage amplitude for each level is constant in conventional inverters. As a result, such as high-precision positioning control of VCM, designing an appropriate inverter for a reference wave that contains a large amount of low-voltage components increases the number of circuit elements. Therefore, this paper proposes a MLI with two unbalanced dc-input voltages, referred to as unbalanced MLIs (UMLIs) hereinafter. This topology uses two different dc-input voltages, and it is possible to reduce the output voltage level in extremely low-voltage range compared to other voltage levels. Simulation results when the high-precision positioning control of the VCM confirm that the proposed UMLIs improves the control performance compared to the conventional FCIs with equal number of output voltage levels and uniform level widths.
During postulated severe accident, large amount of hydrogen-vapor mixture will be released into the containment and inflammable gas mixture may form. Once the gas will be ignited, the generated pressure loads can jeop...
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In severe accident of nuclear power plant, large quantities of steam and radioactive aerosol may release to the containment. Meanwhile, hydrogen may be generated by zirconium-steam reaction and released to the contain...
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This study investigates the impact of roughness elements on fluid flow and heat transfer characteristics in narrow rectangular channels. The results show that when the fluid flows over roughness elements, it induces v...
This study investigates the impact of roughness elements on fluid flow and heat transfer characteristics in narrow rectangular channels. The results show that when the fluid flows over roughness elements, it induces vortices near the wall, disturbing the flow and heat transfer boundary layers. This enhances heat transfer while simultaneously increasing flow resistance. Among different roughness types, cylindrical roughness elements demonstrate a more substantial improvement in both heat transfer efficiency and friction factor compared to cubic elements. The Nusselt number is found to be non-monotonic related to the height of the roughness elements, while the friction factor increases with height. Additionally, larger roughness element diameters lead to higher Nusselt numbers and friction factors. Further analysis reveals that under conditions where the spacing and height remain unchanged, an increase in the roughness elements quantity results in a diminished enhancement of heat transfer. The base edge length of the roughness elements has a more significant impact on heat transfer capacity than the additional heated area, while the additional area primarily affects the flow resistance, causing the friction factor to increase with the number of roughness elements.
In this study, we observe the dynamic behavior of an inflatable robot arm with an internally reinforced drop-stitch structure. We examine the deformation during motion of 1 and 2 degrees of freedom (DOF) for an inflat...
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ISBN:
(数字)9798331531614
ISBN:
(纸本)9798331531621
In this study, we observe the dynamic behavior of an inflatable robot arm with an internally reinforced drop-stitch structure. We examine the deformation during motion of 1 and 2 degrees of freedom (DOF) for an inflatable body. The inflatable robot arm has a soft inflatable body as links and rigid servo actuators as joints. We implemented a sinusoidal motion for inflatable links for various payload conditions and analyzed them using a Motion Capture system. To estimate the dynamic deformation of the balloon in motion, we have defined a Deformation Index (DI) metric. Angle, current of the actuator (servo), and DI are used as input to polynomial regression to predict the end effector position. With this analysis, we can understand the complexity of modeling the nonlinear behavior of inflatable links for multi-DOF motion. We observed DI helps improve the prediction of the end effector position by including deformation information. However, the results demonstrate the limitations of polynomial regression analysis of an internally reinforced inflatable robot arm link.
Recent advances in high-temperature gas-cooled reactor fuel research have captured the global spotlight, as modern operating contexts demand innovative responses to unprecedented challenges. This article offers an ove...
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