Wei LIU

Northeastern University

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Co-Authors

Masatoshi Kureta

Japan Atomic Energy Agency

Hidesada Tamai

Japan Atomic Energy Agency

Hajime Akimoto

National Institute for Environmental Studies

Akira Ohnuki

Mitsubishi Heavy Industries (Germany)

Shuqi Shang

Qingdao Agricultural University

Xiaoning He

Qingdao Agricultural University

Takashi Sato

Waseda University

Zhiyong Wang

Shandong University of Science and Technology

Gang Zhao

Universidad del Noreste

Yunkang LI

Qingdao Agricultural University

Cooperative Institutions

Qingdao Agricultural University

Northeastern University

Japan Atomic Energy Agency

Shandong University of Science and Technology

Advanced Science Research Center

Universidad del Noreste

Huazhong University of Science and Technology

Ministry of Education Science and Technology

Tianjin University

Kobe University

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Critical Power Characteristics in 37-rod Tight Lattice Bundles under Transient Conditions

Journal of Nuclear Science and Technology (2007)

Wei LIU Masatoshi Kureta Hidesada Tamai Akira Ohnuki Hajime Akimoto

Abstract Critical power characteristics in the postulated abnormal transient processes that may be possibly met in the operation of Innovative Water Reactor for Flexible Fuel Cycle (FLWR) were investigated for the design of the FLWR core. Transient Boiling Transition (BT) tests were carried out using two sets of 37-rod tight lattice rod bundles (rod diameter: 13 mm; rod clearance: 1.3 mm or 1.0 mm) at Japan Atomic Energy Agency (JAEA) under the conditions covering the FLWR operating condition (Pex = 7:2 MPa, Tin = 556 K) for mass velocity G = 400-800 kg/(m2 s). For the postulated power increase and flow decrease transients, no obvious change of the critical power against the steady one was observed. The traditional quasi-steady characteristic was confirmed to be working for the postulated power increase and flow decrease transients. The experiments were analyzed with TRAC-BF1 code, where the JAEA newest critical power correlation for the tight lattice rod bundles was implemented for the BT judgment. The TRAC-BF1 code showed good prediction for the occurrence or the non occurrence of the BT and for the exact BT starting time. The traditional quasi-steady state prediction of the BT in transient process was confirmed to be applicable for the postulated abnormal transient processes in the tight lattice rod bundles. KEYWORDS: critical powertransient processtight lattice rod bundlesanalysisTRAC-BF1 codeboiling transitionboiling crisisInnovative Water Reactor for Flexible Fuel CycleFLWR

Transient (computer programming)

Lattice (music)

10.3327/jnst.44.1172

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Citations (6)

A Novel Phase Unwrapping Method Used for Monitoring the Land Subsidence in Coal Mining Area Based on U-Net Convolutional Neural Network

Frontiers in Earth Science (2021)

Zhiyong Wang Lu Li Yaran Yu Wang Jian Zhenjin Li

Large-scale and high-intensity mining underground coal has resulted in serious land subsidence. It has caused a lot of ecological environment problems and has a serious impact on the sustainable development of economy. Land subsidence cannot be accurately monitored by InSAR (interferometric synthetic aperture radar) due to the low coherence in the mining area, excessive deformation gradient, and the atmospheric effect. In order to solve this problem, a novel phase unwrapping method based on U-Net convolutional neural network was constructed. Firstly, the U-Net convolutional neural network is used to extract edge to automatically obtain the boundary information of the interferometric fringes in the region of subsidence basin. Secondly, an edge-linking algorithm is constructed based on edge growth and predictive search. The interrupted interferometric fringes are connected automatically. The whole and continuous edges of interferometric fringes are obtained. Finally, the correct phase unwrapping results are obtained according to the principle of phase unwrapping and the wrap-count (integer jump of 2π) at each pixel by edge detection. The Huaibei Coalfield in China was taken as the study area. The real interferograms from D-InSAR (differential interferometric synthetic aperture radar) processing used Sentinel-1A data which were used to verify the performance of the new method. Subsidence basins with clear interferometric fringes, interrupted interferometric fringes, and confused interferometric fringes are selected for experiments. The results were compared with the other methods, such as MCF (minimum cost flow) method. The tests showed that the new method based on U-Net convolutional neural network can resolve the problem that is difficult to obtain the correct unwrapping phase due to interrupted or partially confused interferometric fringes caused by low coherence or other reasons in the coal mining area. Hence, the new method can help to accurately monitor the subsidence in mining areas under different conditions using InSAR technology.

10.3389/feart.2021.761653

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Citations (6)

Constrained deformation and smoothing technique of discrete curve on surface

Journal of Zhejiang University(Engineering Science) (2008)

Wei LIU

Using an analogy between the control polygon and the bar network,four minimization models as deformation engines,i.e.minimization of the force variations,minimization of the forces,minimization of the bar length were,minimization of the node displacements,were investigated.These minimization problems were formulated as a unified mathematical form by using the nodes perturbation.So it is convenient to obtain a multiple combination of the minimization models which are used to satisfy the various shape requirements.The combination of minimization of the forces and minimization of the node displacements is used for the global and local smoothness.Experimental cases show that the proposed method can be widely applied to curve editing.

Minification

Smoothing

Smoothness

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DESIGN AND EXPERIMENTAL STUDY OF PEANUT PLANTER WITH HIGH-SPEED OPERATION AND CONTROLLABLE SOWING DEPTH

INMATEH Agricultural Engineering (2024)

Moxian LI Xueliang Chang Xiaoning He Ning Zhang Wei LIU

Aiming at the traditional peanut planter seed and fertilizer sowing depth inconsistency caused by seed burning and injury, fertilizer waste and low seed emergence rate, the design of a peanut planter with high-speed operation and controllable seed and fertilizer sowing depth was performed. The laser sensor is added to detect the height of the ridge and the furrow opener position feedback, and the speed sensor detects the operating speed of the peanut planter. The mechanical analysis of the four-link rod clarifies the control principle, improves the PID algorithm of the integral term, designs the control strategy based on the operating speed of the planter, controls the electro-hydraulic system, and realizes the sowing and fertilizing depth adjustment of the furrow opener. Through the design of three-factor three-level orthogonal simulation test, it is concluded that the vehicle speed and height deviation value are significant factors affecting the sowing and application depth, and under the verification of the field test, it is obtained that when the sowing depth is 50 mm under the speed of 3 km/h, the dynamic sowing depth qualification rate is 96.26%, and the maximum coefficient of variation of the sowing depth is 2.58%, which improves the effect of the existing control of the sowing depth of the peanut by 6.05%, and reduces the variation of the sowing depth by 2.85%. The research has demonstrated superior performance compared to traditional mechanical adjustment in regulating the planting depth of peanuts, thereby achieving the intended design objective.

10.35633/inmateh-72-11

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Citations (3)

Information Systems Security Assessment Based on System Dynamics

International Journal of Security and Its Applications (2015)

Wei LIU Yong-feng Cui Li Ya

With the rapid development of information technology, information systems security becomes more and more important for both national economics and people's everyday life.Therefore, in this paper, we study on the problem of information systems security assessment.However, existing traditional methods has two major issues.First, it is unclear that whether there remains severe potential risks unrecognized, and thus the reliability is limited.Second, the assessment results deviate from the real one due to the time and environmental restrictions, the subjective reasons of the researchers, or biased observed data, etc.To this end, we propose to leverage system dynamics (SD) for information systems security assessment.Specifically, based on the analysis of casual loops and positive and negative feedbacks among factors, we explore potential risks and capture those who are impossible to be measured using traditional methods.

Dynamics

Information systems security

10.14257/ijsia.2015.9.2.08

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Citations (17)

Load-Balancing Routing Algorithm Based on Segment Routing for Traffic Return in LEO Satellite Networks

IEEE Access (2019)

Wei LIU Ying Tao Liang Liu

To tackle the network congestion problem caused by ground gateway stations arranged within a limited area in low earth orbit (LEO) satellite networks, a routing algorithm based on segment routing for traffic return is proposed. Light and heavy load zones are dynamically divided according to the relative position relationship between gateways and the reverse slot. The pre-balancing shortest path algorithm is used in the light load zone, and the minimum weight path defined by congestion index is the routing rule in the heavy load zone. Then, the consistent forwarding is performed referring to segment routing in all zones. Simulation conditions are different sizes of heavy load zone, different traffic density distributions, and different traffic demands. Simulation results confirm that the load-balancing performance is improved significantly with the extension of the heavy load zone size in terms of the average rejection ratio, the average relative throughput, the maximum link utilization, and the average delay. The proposed algorithm is an alternative solution and guidance for routing strategy in LEO satellite networks.

Equal-cost multi-path routing

10.1109/access.2019.2934932

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Citations (45)

Preparation and High-temperature Properties of Nanostructured CeO2/ZrO2-Y2O3 Thermal Barrier Coating

Journal of Inorganic Materials (2010)

Wen-Biao GONG Yu-Peng LI Wei LIU Da-Qian SUN Wen-Quan WANG

10.3724/sp.j.1077.2010.00860

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Citations (2)

RESEARCH AND ANALYSIS OF BIONIC GOLDEN CICADA PEANUT DIGGING SHOVEL

INMATEH Agricultural Engineering (2022)

Baiqiang ZUO Shuqi Shang Xiaoning He Zelong ZHAO Dongjie LI

In order to reduce the high resistance problem during peanut digging shovel operation and improve the soil loosening effect, a bionic peanut digging shovel was designed according to the streamlined profile of the head of the golden cicada, and the range of values of the digging operation parameters was analyzed. A discrete element model was developed to verify that the operational resistance of the bionic excavation shovel is lower than that of the flat shovel. The reliability of the simulation test was confirmed by conducting a resistance test on the excavation shovel through a soil trench test. A three-factor, three-water orthogonal combination test was designed to determine the optimal operating parameters of the excavation shovel: the bevel angle of the shovel blade was 55°, the digging depth was 130 mm, and the width of the shovel face was 309 mm. The paper can provide a reference for designing and optimizing peanut-digging shovels.

Shovel

Digging

10.35633/inmateh-68-64

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Citations (2)

Gap Width Effect on Critical Power based on Tight-Lattice 37-Rod Bundle Experiments

Journal of Nuclear Science and Technology (2007)

Hidesada Tamai Masatoshi Kureta Wei LIU Takashi Sato Akira Ohnuki

Since most critical power data have been collected for tube, annulus, or BWR geometries under BWR flow conditions, there is a lack of the critical power data for very tight triangular lattice bundles under low mass velocity flow conditions that is indispensable for the thermal-hydraulic design of the Innovative Water Reactor for FLexible Fuel Cycle (FLWR). Large-scale thermal-hydraulic experiments using two tight-lattice 37-rod bundle test sections with 1.0 and 1.3 mm gaps respectively were therefore carried out within the range of 2–9 MPa in pressure and 150–1200 kg/m2 s in mass velocity. It was confirmed that the fundamental characteristics of the flow parameter impact on critical power are similar between 1.0 and 1.3 mm gaps. Then, the gap width effect was discussed using the relationship between critical quality and mass velocity. No significant differences are recognized under high mass velocity conditions (>700 kg/m2 s), whereas the critical quality in the 1.0 mm gap experiments tends to be lower under low mass velocity conditions (>700 kg/m2 s) and the difference is less than 10%.

Thermal hydraulics

Annulus (botany)

Mass flow

Critical mass (sociodynamics)

Hydraulic diameter

Critical ionization velocity

Mass flow rate

10.3327/jnst.44.54

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Citations (9)

RELATIONSHIP BETWEEN S WAVE VELOCITIES AND MACROCRACKS IN SANDSTONE DURING THE HEATING TRIAXIAL TEST

Journal of Chengdu University of Technology (1999)

Wei LIU

The relationship between wave velocity and stress in the sandstone during the heating triaxial tests was studied with MTS815 servo control test machine. Based on the analysis of the test results, a new criterion for the stress value of stress induced microcracks is presented with the peak value of the S wave velocity. The appearance that the S wave velocity peak value and the velocity began to decrease illustrates new microcracks were produced in the sandstone test sample. When new stress induced microcracks present, the stress values are different, along with it, the clay content and porosity are not alike. The peak value of the S wave velocity appears when the fracture strength of the tight sandstone is 55%, and that of the S wave velocity appears when the fracture strength of the loose sandstone is 70%. The new stress induced microcracks were determined by the peak value of the S wave velocity means and can be extended in test of solid material.

Triaxial shear test

S-wave

Wave velocity

P wave

Stress wave

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