Simulation analysis and evaluation of decontamination effect of different abrasive jet process parameters on radioactively contaminated metal

Zhong Lin,Deng Jian,Zuo Zhe-wen,Huang Can-yu,Chen Bo,Lei Lin,Lei Ze-yong,Lei Jie-heng,Zhao Mu,Hua Yun-fei 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.11

A new method of numerical simulating prediction and decontamination effect evaluation for abrasive jet decontamination to radioactively contaminated metal is proposed. Based on the Computational Fluid Dynamics and Discrete Element Model (CFD-DEM) coupled simulation model, the motion patterns and distribution of abrasives can be predicted, and the decontamination effect can be evaluated by image processing and recognition technology. The impact of three key parameters (impact distance, inlet pressure, abrasive mass flow rate) on the decontamination effect is revealed. Moreover, here are experiments of reliability verification to decontamination effect and numerical simulation methods that has been conducted. The results show that: 60Co and other homogeneous solid solution radioactive pollutants can be removed by abrasive jet, and the average removal rate of Co exceeds 80%. It is reliable for the proposed numerical simulation and evaluation method because of the well goodness of fit between predicted value and actual values: The predicted values and actual values of the abrasive distribution diameter are Ф57 and Ф55; the total coverage rate is 26.42% and 23.50%; the average impact velocity is 81.73 m/s and 78.00 m/s. Further analysis shows that the impact distance has a significant impact on the distribution of abrasive particles on the target surface, the coverage rate of the core area increases at first, and then decreases with the increase of the impact distance of the nozzle, which reach a maximum of 14.44% at 300 mm. It is recommended to set the impact distance around 300 mm, because at this time the core area coverage of the abrasive is the largest and the impact velocity is stable at the highest speed of 81.94 m/s. The impact of the nozzle inlet pressure on the decontamination effect mainly affects the impact kinetic energy of the abrasive and has little impact on the distribution. The greater the inlet pressure, the greater the impact kinetic energy, and the stronger the decontamination ability of the abrasive. But in return, the energy consumption is higher, too. For the decontamination of radioactively contaminated metals, it is recommended to set the inlet pressure of the nozzle at around 0.6 MPa. Because most of the Co elements can be removed under this pressure. Increasing the mass and flow of abrasives appropriately can enhance the decontamination effectiveness. The total mass of abrasives per unit decontamination area is suggested to be 50 g because the core area coverage rate of the abrasive is relatively large under this condition; and the nozzle wear extent is acceptable

A 3-D Steady-State Analysis of Thermal Behavior in EHV GIS Busbar

Lei, Jin,Zhong, Jian-ying,Wu, Shi-jin,Wang, Zhen,Guo, Yu-jing,Qin, Xin-yan The Korean Institute of Electrical Engineers 2016 Journal of Electrical Engineering & Technology Vol.11 No.3

Busbar has been used as electric conductor within extra high voltage (EHV) gas insulated switchgear (GIS), which makes EHV GIS higher security, smaller size and lower cost. However, the main fault of GIS is overheating of busbar connection parts, circuit breaker and isolating switch contact parts, which has been already restricting development of GIS to a large extent. In this study, a coupled magneto-flow-thermal analysis is used to investigate the thermal properties of GIS busbar in steady-state. A three-dimensional (3-D) finite element model (FEM) is built to calculate multiphysics fields including electromagnetic field, flow field and thermal field in steady-state. The influences of current on the magnetic flux density, flow velocity and heat distribution has been investigated. Temperature differences of inner wall and outer wall are investigated for busbar tank and conducting rod. Considering the end effect in the busbar, temperature rise difference is compared between end sections and the middle section. In order to obtain better heat dissipation effect, diameters of conductor and tank are optimized based on temperature rise simulation results. Temperature rise tests have been done to validate the 3-D simulation model, which is observed a good correlation with the simulation results. This study provides technical support for optimized structure of the EHV GIS busbar.

Two Maternal Lineages Revealed by Mitochondrial DNA D-loop Sequences in Chinese Native Water Buffaloes (Bubalus bubalis)

Lei, Chu-Zhao,Zhang, Wei,Chen, Hong,Lu, Fan,Ge, Qing-Lan,Liu, Ruo-Yu,Dang, Rui-Hua,Yao, Yun-Yi,Yao, Li-Bo,Lu, Zi-Fan,Zhao, Zhong-liang Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.4

Little is known about the origin and genetic diversity of swamp buffaloes in China. To obtain more knowledge on genetics of the water buffalo in China, the complete mitochondrial D-loop sequences of 30 samples from 6 native types were investigated. The results revealed 12 mitochondrial haplotypes with 50 polymorphic sites. Among these polymorphic sites, there were 49 transitions and 1 transversion. The average nucleotide diversity and haplotype diversity estimated from mtDNA D-loop region in 6 Chinese water buffalo types were 0.00684 and 0.798, respectively, showing rather abundant mitochondrial genetic diversity. The Neighbor-Joining (NJ) tree of mtDNA of Chinese water buffaloes was constructed according to the 12 haplotypes. The NJ tree indicated two lineages being designated lineage A and lineage B, in which lineage A was predominant, and lineage B was at low frequency. The new lineage B was first discovered and defined in 6 Chinese water buffalo types. These results showed that two different maternal lineages were involved in the origin of domestic swamp buffaloes in China and the lineage B was probably an introgression from Southeast Asian buffaloes.

Reduction of Target Volume and the Corresponding Dose for the Tumor Regression Field after Induction Chemotherapy in Locoregionally Advanced Nasopharyngeal Carcinoma

Lei Wang,Zheng Wu,Dehuan Xie,Ruifang Zeng,Wanqin Cheng,Jiang Hu,Shaomin Huang,Shu Zhou,Rui Zhong,Yong Su 대한암학회 2019 Cancer Research and Treatment Vol.51 No.2

Purpose This study aims to investigate the feasibility of contouring target volume according to residual tumor and decreasing the dose to the tumor regression field after induction chemotherapy (IC) in locoregionally advanced nasopharyngeal carcinoma (NPC). Materials and Methods From August 2009 to August 2013, patients with stage III–IVB NPC were treated with IC and concurrent chemoradiotherapy. Gross tumor volume of nasopharynx (GTVnx)–residual and gross tumor volume of cervical lymph node (GTVnd)–residual were contoured according to post-IC residual primary tumor and any N+ disease, respectively. The tumor regression field was included in CTVnx1/CTVnd1 and prescribed a dose of 60 Gy. Outcomes and toxicities of all patients were evaluated. Results A total of 57 patients were enrolled. At a median follow-up of 68 months, three cases displayed locoregional recurrence and one case showed both distant metastasis and locoregional recurrence. All locoregional recurrences were in the GTVnx-residual/GTVnd-residual and in-field. The 5-year overall, locoregional relapse-free, distant metastasis-free, and progression- free survival rates were 82.2%, 87.7%, 85.8% and 80.3%, respectively. Conclusion After IC, contouring of GTVnx-residual/GTVnd-residual as residual tumor volume and distribution 60 Gy of radiation dose to the tumor regression field may be feasible and need further investigation.

Experimental Investigation of a Segmented Flap System of a Cranked-Arrow Wing

Zhong LEI,Dong-Youn KWAK,Kentaro HIGUCHI,Kenichi RINOIE 한국항공우주학회 2008 한국항공우주학회 학술발표회 논문집 Vol.- No.-

A parametric study has been conducted for a segmented flap system of a cranked-arrow wing in a low-speed wind tunnel. The objectives were, (1) to develop design methodology for a multi-segment flap system. (2) to investigate the effect of leading- and trailing-edge flaps on the aerodynamic performance at take-off and landing conditions. (3) to construct database for design of high-lift. device, and (4) to validate the numerical simulation used for design. In this paper. effects of deflection angle of leading- and trailing-edge flaps on the aerodynamic performance will be discussed. Analysis of experimental data indicated that the segmented flaps were more effective than the uniform deflected flaps and an optimal combination of flap deflection angles had significant effects to improve the aerodynamic performance.

Design strategies of supported metal-based catalysts for efficient oxidative desulfurization of fuel

Lei Chen,Zhong-Yong Yuan 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.108 No.-

The consumption of fuel oil containing sulfur compounds produces SOx, which inevitably leads to severeenvironmental pollution and even threatens human health. Oxidative desulfurization (ODS) has beenidentified as a promising pathway to produce clean fuel by virtue of its high efficiency and mild reactionconditions. In recent years, supported metal-based catalysts have attracted scientific research interestdue to the high activity and remarkable recyclability for ultra-deep ODS reactions. In this review, the latestresearch progress on the supported metal-based ODS catalysts is summarized. The reaction mechanismof the supported metal-based ODS catalysts is briefly discussed based on the different metalactive components. Notably, we focus on summarizing the design strategies of highly efficient supportedmetal-based ODS catalysts, with special emphasis on the creation of the concentrated microenvironmentof reactants around active sites, construction of highly effective catalytically active sites and improvementof recyclability. These improved strategies are also applicable to the development of the supportedmetal-based catalysts for other green catalytic reactions. In addition, the current issues and future developmenttrends of the supported metal-based ODS catalysts are pointed out.

Coverage Optimization Scheme Based on Artificial Fish Swarm Algorithm for Wireless Sensor Networks in Complicated Environment

Lei HONG,Rui ZHONG 보안공학연구지원센터 2014 International Journal of Future Generation Communi Vol.7 No.5

Selective transformation of biomass-derived 5-hydroxymethylfurfural into 2,5-dihydroxymethylfuran via catalytic transfer hydrogenation over magnetic zirconium hydroxides

Lei Hu,Mei Yang,Ning Xu,Jiaxing Xu,Shouyong Zhou,Xiao-Zhong Chu,Yijiang Zhao 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.1

An economical and effective approach for the selective transformation of biomass-derived 5-hydroxymethylfurfural (HMF) into 2,5-dihydroxymethylfuran (DHMF) was developed by catalytic transfer hydrogenation over various magnetic zirconium hydroxides (MZHs). As expected, MZH with a moderate Zr/Fe molar ratio of 2 displayed the highest catalytic activity, resulting in 98.4% HMF conversion and 89.6% DHMF yield at 150 oC for 5 h in the presence of 2-butanol that simultaneously acted as the hydrogen donor and reaction solvent, which was ascribed to its appropriate specific surface area, pore size and acid-base content. Moreover, a plausible reaction mechanism for the catalytic transfer hydrogenation of HMF into DHMF over MHZ(Zr/Fe=2) was also proposed, in which the basic hydroxyl groups with the aid of acidic zirconium metal centers were considered to be responsible for the pivotal hydride transfer via a six-membered ring structure.

Disassembly Line Balancing Optimization Method for High Efficiency and Low Carbon Emission

Lei Zhang,Xikun Zhao,Qingdi Ke,Wanfu Dong,Yanjiu Zhong 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.1

Disassembly is the first step in product recycling and remanufacturing. When disassembling large quantities of products, the disassembly efficiency is crucial for enterprises. Thus, disassembly line is the best choice for automated disassembly of disposal products. Disassembling products, especially complex structure of products, consume a lot of resources and energy and produce large amounts of carbon emissions. So, it is essential for disassembly line to work efficiently and environmentally. In this paper, the hybrid graph is proposed to express the direct and indirect constraint relationship among components. Then, the mathematical model of carbon emission is built by quantifying the carbon emissions in the process of product disassembly. Taking into account the basic disassembly time, direction change time and tool change time, the mathematical model of high efficiency is presented for optimizing disassembly time. Additionally, based on the traditional multi-objective disassembly line balancing problem (DLBP), a novel multi-objective optimization model of the DLBP with shortest disassembly time and minimum carbon emissions is proposed for improving disassembly efficiency and reducing the carbon emissions in the process of disassembly. Furthermore, genetic algorithm is presented for optimizing the disassembly sequence. Finally, an automobile engine is given as an example to confirm the practicality of the proposed model in solving the DLBP.

MTHFR Polymorphisms and Pancreatic Cancer Risk:Lack of Evidence from a Meta-analysis

Li, Lei,Wu, Sheng-Di,Wang, Ji-Yao,Shen, Xi-Zhong,Jiang, Wei Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5

Objective: Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms have been reported to be associated with pancreatic cancer, but the published studies had yielded inconsistent results.We therefore performed the present meta-analysis. Methods: A search of Google scholar, PubMed, Cochrane Library and CNKI databases before April 2012 was conducted to summarize associations of MTHFR polymorphisms with pancreatic cancer risk. Assessment was with odds ratios (ORs) and 95% confidence intervals (CIs). Publication bias were also calculated. Results: Four relative studies on MTHFR gene polymorphisms (C667T and A1298C) were involved in this meta-analysis. Overall, C667T(TT vs. CC : OR = 1.61, 95%CI = 0.78 - 3.34; TT vs. CT : OR = 1.41, 95%CI = 0.88-2.25; dominant model: OR = 0.68, 95%CI = 0.40-1.17; recessive model: OR = 0.82, 95%CI = 0.52-1.30) and A1298C(CC vs. AA:OR=1.01, 95%CI=0.47-2.17; CC vs. AC: OR=0.99,95%CI=0.46-2.14; dominant model: OR=1.01, 95%CI = 0.47-2.20; recessive model: OR = 1.01, 95%CI = 0.80-1.26) did not increase pancreatic cancer risk. Conclusion: This meta-analysis indicated that MTHFR polymorphisms (C667T and A1298C) were not associated with pancreatic cancer risk.