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

The Recognition Method of Radiation Source Based on Information Entropy and Cloud Model

Yun Lin,Can Wang,Chunguang Ma,Zheng Dou,Zhiqiang Wu,Zhiping Zhang 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.2

Information entropy features are often used for radiation source signal recognition, but due to the information entropy is very sensitive to noise, so this method has greater recognition rate changes with the SNR. This paper putting forward a viable recognition based on Entropy and cloud model. using cloud model to extract secondary features of signals, build radiation source signal’s entropy and cloud feature vector. The method uses cloud model description and processing interval fuzzy and observation noise data, better solve the low SNR cases of radiation source signal feature extraction problem. At the same time, putting forward the similar cloud classification recognition algorithm based on cloud model. The simulation results show that Entropy and cloud model has better recognition effect under low SNR, which can improve the signals’ recognition rate under low SNR.

Variations in bacterial and fungal communities through soil depth profiles in a Betula albosinensis forest

Can Du,Zengchao Geng,Qiang Wang,Tongtong Zhang,Wenxiang He,Lin Hou,Yueling Wang 한국미생물학회 2017 The journal of microbiology Vol.55 No.9

Microbial communities in subsurface soil are specialized for their environment, which is distinct from that of the surface communities. However, little is known about the microbial communities (bacteria and fungi) that exist in the deeper soil horizons. Vertical changes in microbial alpha-diversity (Chao1 and Shannon indices) and community composition were investigated at four soil depths (0–10, 10–20, 20–40, and 40–60 cm) in a natural secondary forest of Betula albosinensis by high-throughput sequencing of the 16S and internal transcribed spacer rDNA regions. The numbers of operational taxonomic units (OTUs), and the Chao1 and Shannon indices decreased in the deeper soil layers. Each soil layer contained both mutual and specific OTUs. In the 40–60 cm soil layer, 175 and 235 specific bacterial and fungal OTUs were identified, respectively. Acidobacteria was the most dominant bacterial group in all four soil layers, but reached its maximum at 40–60 cm (62.88%). In particular, the 40–60 cm soil layer typically showed the highest abundance of the fungal genus Inocybe (47.46%). The Chao1 and Shannon indices were significantly correlated with the soil organic carbon content. Redundancy analysis indicated that the bacterial communities were closely correlated with soil organic carbon content (P = 0.001). Collectively, these results indicate that soil nutrients alter the microbial diversity and relative abundance and affect the microbial composition.

Imaging Features of Pediatric Pentastomiasis Infection: a Case Report

Can Lai,Xi Qun Wang,Long Lin,De Chun Gao,Hong Xi Zhang,Yi Ying Zhang,Yin Bao Zhou 대한영상의학회 2010 Korean Journal of Radiology Vol.11 No.4

We report here a case of pentastomiasis infection in a 3-year-old girl who had high fever, abdominal pain, abdominal tension and anemia. Ultrasound scanning of the abdomen revealed disseminated hyperechoic nodules in the liver and a small amount of ascites. Abdominal MRI showed marked hepatomegaly with disseminated miliary nodules of high signal intensity throughout the hepatic parenchyma on T2-weighted images; retroperitoneal lymphadenopathy and disseminated miliary nodules on the peritoneum were also noted. Chest CT showed scattered small hyperdense nodules on both sides of the lungs. The laparoscopy demonstrated diffuse white nodules on the liver surface and the peritoneum. After the small intestinal wall and peritoneal biopsy, histological examination revealed parenchymal tubercles containing several larvae of pentastomids and a large amount of inflammatory cell infiltration around them. The pathological diagnosis was parasitic granuloma from pentastomiasis infection.

Multi-Population Genetic Algorithm for Identifying Mutated Driver Pathways in Cancer

Shu-Lin Wang,Can-jun Hu 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.4

The cancer is one of the diseases of serious threat to mankind's health and life nowadays. Resistance to radiation and chemotherapy is a significant obstacle to the treatment of advanced cancer. Gene therapy is a new therapeutic tool for the treatment of diverse types of diseases, including cancer, congenital genetic, infectious diseases. It is well known that the somatic mutation is an important factor that might lead to cancer development. It is difficult to distinguish driver mutations from passenger mutations because of mutational heterogeneity, which is the key to solve and deal with the problem of cancer treatment. In this study, we find an efficient way Multi-Population Genetic Algorithm to solve the maximum weight submatrix problem which is designed to find important mutated driver genes in cancer, then makes the factors comparison of the methods on the simulated and several real mutation datasets. The results show that MPGA performs more efficiently, In addition, MPGA is a most robust method among these approaches, and these important pathways in these cancers are successfully rediscovered. The approach achieved what we expect.

Experimental Study of Factors Affecting the 7075 Aluminum Alloy Thin-walled Parts Milling Force

Fengyun Yu,Lin Wu,Yunliang Fu,Yanyan Guo,Can Zhao,Xufeng Wang 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.8

Taking 7075 aluminum alloy thin-walled part as the research object, with higher cutting parameters than the normal value selected, a four factors and four levels orthogonal experiment was carried out, in which we chose YG carbide cutting tools for the milling, intercepted the milling force stable section, selected ten peak values and took an average, conducted multiple linear regression analysis using Matlab numerical calculation software and established the milling force empirical formula of 7075 aluminum alloy thin-walled part to study the factors which have influence on its milling force. By range analysis of the experimental results, the cutting force change rule in the manufacturing process of aluminum alloy with the change of cutting parameter was revealed. It is found that the axial cutting depth had the greatest influence on the force perpendicular to the direction of cutting surface, and the radial cutting depth had the minimal impact. By comparative analysis on theoretical value and experimental value of milling forces, we found that the predicted value of the milling force Fx and Fy in theory were in good agreement with the experimental results with a relative error less than 8.7%. Under the experimental conditions, the optimal milling parameters are axial cutting depth of 2mm, radial cutting depth of 0.5mm, feed speed 95mm/min and cutting speed of 23.86m/min. It will provide data and experiment support for milling of thin-walled parts of similar materials, which will have important practical value and theoretical significance for engineering.

Influence of Water on the Methanation Performance of Mo-Based Sulfur-Resistant Catalysts with and without Cobalt Additive

Haiyang Wang,Can Lin,Zhenhua Li,Baowei Wang,Xinbin Ma 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.1

The activities of Mo-based and Co-containing Mo-based catalysts for sulfur-resistant methanation in the presence and the absence of water are compared. When water was added to the Mo-based catalyst, its methanation activity decreased and the activity could not be recovered even after the water was removed from the system. However, for the Co-containing Mo-based catalysts, the formation of Co9S8 improved not only the methanation activity of the catalyst as active sites but also the stability of the catalyst especially in water-containing hydrogenation. The deactivation of the Mo-based catalyst in the presence of water is mainly due to reduction of the external acid sites and fewer molybdenum sulfide (MoS2) stacks. The addition of Co protects the active MoS2 phase, thereby preventing the deactivation of the catalyst in the presence of water.

Physical property effects of the compression process with supercritical carbon dioxide as working fluid

Jinlan Gou,Kelong Zhang,Yuansheng Lin,Yong Li,Can Ma,Hanbing Ke 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.8

The compressor is one of the key components in the closed supercritical carbon dioxide (S-CO 2 ) Brayton cycle, but its design method is far from mature. It is naturally expected that the well-established design method of the air compressor can provide favorable guidelines, on the basis of further understanding the effects of the physical property on the compressor flow field. Considering that isentropic compression is one of the core physical processes in the compressor, the physical property effects on this process were mainly investigated in this work. Similarity criterion was considered, and the change rate discrepancy of the main variables in this process between S-CO 2 and the ideal air was fully analyzed. Results show that S-CO 2 is compressed faster than the ideal air in most cases, along with generating smaller Mach number and larger pressure rise ratio. It is noted the important parameter of the static pressure coefficient distribution with S-CO 2 in the compression process is almost the same as that with the ideal air at low Mach number, which is conductive to the extension of the air compressor research experience, but it is quite different at high Mach number. The simulation cases about compressor cascade are further applied and prove the suitability of the revealed physical property effects in the compressor passage. Understanding these effects on the compression process is helpful to improve the design method of the S-CO 2 compressor.

Pap Smear Combined with HPV Testing: A Reasonable Tool for Women with High-grade Cervical Intraepithelial Neoplasia Treated by LEEP

Mo, Ling-Zhao,Song, Hong-Lin,Wang, Jian-Li,He, Qing,Qiu, Zhang-Can,Li, Fei Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.10

Background: To evaluate HPV testing by Hybrid Capture II (HCII) in conjunction with cytology in detecting the residual/recurrence disease after treatment of high-grade cervical intraepithelial neoplasia (CIN II-III) with loop electrosurgical excision procedure (LEEP). Materials and Methods: A retrospective review of 158 patients with histologically confirmed CIN II-III who underwent LEEP between January 2011 and October 2012 was conducted. Post-treatment control was scheduled at the 3rd, 6th, 12th and 18th month. All patients were followed up by Pap smear and HR-HPV genotype and viral load testing. Results: Pre-treatment, HR-HPV DNA, was detected in all specimens of the patients. At follow-up, 25 patients were diagnosed as the residual/recurrent disease during the FU visit, among whom, 16 patients with positive margin: 13 patients (52%) with HR-HPV DNA+/cytology+, 2 patients (8%) with HR-HPV DNA+/cytology-, 1 patient (4%) with cytology+/HR-HPV DNA-; 9 patients with clean margin - 5 patients (55.6%) with HR-HPV DNA+/cytology+; 2 patients (22.2%) with HRHPV DNA+/cytology-, 2 patients (22.2%) with cytology+/HR-HPV DNA-. None of them persisting HR-HPV DNA-/cytology-with positive or negative margin was identified as the residual/recurrent disease. The majority of residual/recurrent disease was detected at the 12th and 18th month FU, and there was almost no difference in the sensitivity and negative predictive value (NPV) between at the 3rd month and the 6th month FU visits. 14 residual/recurrence disease (14/46:30.4%) had pre-treatment high viral load (>5 000 RUL/PC) and 11 (11/112, 9.8%) with pre-treatment low viral load, P<0.05. Conclusions: (1) The persistence HR-HPV DNA is the root cause of the residual/recurrent disease for the women treated for high-grade CIN; the pre-treatment viral load and margin can be seen as the predictor. (2) The FU visit beginning at the 6th month post-treatment and lasting at least 24 months with the combination of cytology and HPV testing. (3) Patients with high pre-treatment HPV load, which is considered as one risk of developing the residual/recurrent disease, should be paid more attention (especially above 500RUL/PC) to by clinicians.

Influence of chlorinated disinfection by-products on transmission of antibiotic resistance genes in biofilms and water of a simulated drinking water distribution system

Minglu Zhang,Lingyue Zhang,Kaizong Lin,Yue Wang,Shaofeng Xu,Miao Bai,Hairong Jiang,Shuangling Wang,Yongjing Wang,Can Zhang 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.4

The spread of antibiotic resistance genes (ARGs) caused by biofilm growth in drinking water distribution systems (DWDSs) poses a serious threat to human health. The influence of disinfection by-products (DBPs) on the distribution of ARGs and mobile genetic elements (MGEs) in different phases (biofilms and water) of DWDSs is unclear. In this study, the characteristics of microbial indices, trihalomethanes (THMs), haloacetic acids (HAAs), ARGs and MGEs in biofilms and effluents of simulated DWDS reactors were detected during 150 d of operation. During the mature biofilm periods of 90 d or 120 d, for both biofilms and effluents, seven categories of ARGs (except tetracycline) and MGEs were at their highest and lowest relative abundance in the entire operation cycle, respectively. The influence of DBPs on ARGs and MGEs in the DWDS was different in different phases. In effluents, DBPs showed a stronger relationship with ARGs compared with MGEs. THMs and HAAs had positive correlations with various ARGs, which indicated that DBPs affected the distribution of resistance genes. In biofilms, the influence of MGEs on ARGs was stronger than that of DBPs on ARGs. Thus, DBPs might be an important contributor to the enrichment and spread of ARGs in water.