Status and initial experiments of DRAGON-V facility for lithium-lead blanket technologies of hydrogen fusion reactors

A dual-coolant integrated experimental facility named DRAGON-V has been developed at the Institute of Nuclear Energy Safety Technology, Hefei Institute of Physical Science, Chinese Academy of Sciences, for the key technology research and performance evaluation of candidate liquid lithium-lead (PbLi) blanket of hydrogen fusion reactors. The loop is composed of a material test sub-loop and thermal-hydraulic test sub-loop, the design parameters are PbLi inventory 20 tons, PbLi temperature up to 550 °C, the maximum PbLi flow rate up to 40 kg/s. A novel cold trap system is designed to remove the suspended and crystalized impurities in PbLi fluid with three cooling zones and cross row arrangement of rod bundle filter elements. The paper describes the loop itself and its major components, initial loop testing, flow and measurement diagnostics and current experiments. The obtained test results of the loop and its components have demonstrated that the new facility is fully functioning and ready for experimental studies of material corrosion with/without a magnetic field, magnetohydrodynamic (MHD) effect, purification, heat and mass transfer phenomena in PbLi flows and can also be used in mock-up testing in conditions relevant to fusion applications.     

Co?N graphene encapsulated cobalt catalyst for H2O2 decomposition under acidic conditions

Hydrogen peroxide (H₂O₂) has been listed as one of the 100 most important chemicals in the world. However, huge amount of residual H₂O₂ is hard to timely decomposed into O₂ and H₂O under acidic condition, easily resulting in explosion hazard. Here, we reported a core–shell structure catalyst, that is graphene with Co N structure encapsulated Co nanoparticles. Co N graphene shell serves as the active site for the H₂O₂ decomposition, and Co core further enhance this decomposition. Benefiting from it, the H₂O₂ decomposition were close to 100% after 6 cycles without pH adjustment, which increased 6 orders of magnitude compared with no catalyst. At the same time, the O₂ generation reached 99.67% in 2 h with little metal leaching, and ·OH has been greatly inhibited to only 0.08%. This work can cleanly remove H₂O₂ with little deep oxidation and protect the process of H₂O₂ utilization to achieve a safer world.     

Study on vapour dispersion and explosion from compressed hydrogen spill: Risk assessment on a hydrogen plant

Hydrogen produced from renewable resources is one of the cleanest fuels and could be used to store intermittent solar, wind and other energies. The main concern about using hydrogen is its hazards, such as high storage pressure, wide-range flammability, low mass density, and high diffusion. This study investigated the hazards of compressed hydrogen storage by developing a CFD model to understand the gas dispersion behaviour. The model was validated using the past experimental data and showed a good agreement, which could demonstrate the diffusion characteristics and gas stratification of a buoyant gas. A case study of an accidental release of compressed hydrogen from a storage tank was investigated to evaluate the risk of a hydrogen plant. A mathematical model of the jet spill was used to account for the choking effect from a high-pressure release to ensure the input velocity in CFD simulation is suitable for modelling gas dispersion using verified spatial and temporal scales, then the simulation results were used as inputs of vapour cloud explosions (VCEs) to investigate the potential overpressure effect. It was found the CFD model could predict a more reasonable flammable gas amount in cloud than using the bulk hydrogen release rate. The safety distance based on the overpressure prediction was reduced by 35%. The method proposed in this study can provide more validity for the consequence analysis as part of risk assessment.     

Prediction of fish quality level with machine learning

In this study, sea bream, sea bass, anchovy and trout were captured and recorded using a digital camera during refrigerated storage for 7 days. In addition, their total viable counts (TVC) were determined on a daily basis. Based on the TVC, each fish was classified as ‘fresh’ when it was <5 log cfu per g, and as ‘not fresh’ when it was >7 log cfu per g. They were uploaded on a web-based machine learning software called Teachable Machine (TM), which was trained about the pupils and heads of the fish. In addition, images of each species from different angles were uploaded to the software in order to ensure the recognition of fish species by TM. The data of the study indicated that the TM was able to distinguish fish species with high accuracy rates and achieved over 86% success in estimating the freshness of the fish species tested.     

Additional deepwater sampling of prey fish in Lake Michigan annual bottom trawl survey reveals new insights for depth distribution dynamics

Beginning in 2013, sites at the 128-m bottom depth contour were added to the sampling design of the annual Lake Michigan bottom trawl survey for prey fish, which has been conducted by the U.S. Geological Survey Great Lakes Science Center (GLSC) each fall since 1973, to better assess fish depth distributions in a changing ecosystem. The standard sampling design included bottom depths from 9 to 110 m, although the GLSC also sporadically conducted bottom trawl tows at the 128-m bottom depth contour during 1973–1988. Enactment of this new sampling design in 2013 revealed that mean biomass density of deepwater sculpins (Myoxocephalus thompsonii) at the 128-m depth exceeded the sum of mean biomass densities at shallower depths, indicating that the bulk of the deepwater sculpin population is residing in waters deeper than 110 m. Thus, our findings supported the hypothesis that the depth distribution of the deepwater sculpin population had shifted to deeper waters beginning in 2007, thereby explaining, at least in part, the marked decline in deepwater sculpin abundance since 2006 based on the standard sampling design. In contrast, our results did not support the hypothesis that the slimy sculpin (Cottus cognatus) population had shifted to deeper waters sometime after 2000. A portion of the burbot (Lota lota) population may have also shifted in depth distribution to waters deeper than 110 m after 2007, based on our results. Our findings have served as an impetus to further expand the range of depths sampled in our bottom trawl survey.     

Fire safe,sustainable loose furnishing

The aim of this exploratory study has been to investigate the fire properties and environmental aspects of different upholstery material combinations, mainly for domestic applications. An analysis of the sustainability and circularity of selected textiles, along with lifecycle assessment, is used to qualitatively evaluate materials from an environmental perspective. The cone calorimeter was the primary tool used to screen 20 different material combinations from a fire performance perspective. It was found that textile covers of conventional fibres such as wool, cotton and polyester, can be improved by blending them with fire resistant speciality fibres. A new three‐dimensional web structure has been examined as an alternative padding material, showing preliminary promising fire properties with regard to ignition time, heat release rates and smoke production.     

某福利院一起肠炎沙门菌食源性疾病的调查分析

目的 对某福利院一起肠炎沙门菌食源性疾病进行调查和溯源,为研究相关食源性疾病提供参考。方法采用流行病学、食品卫生学和脉冲场凝胶电泳(PFGE)同源性分析等方法,分析本次食源性疾病事件。结果 确认本次事件中病例23名,患病率5.65%(23/407)；现场采集病例肛拭子15份和厨房工作人员肛拭子3份、留样菜品3份、水果2份以及冰棒1份,其中从11份病例肛拭子中检出肠炎沙门菌,PFGE结果显示11株肠炎沙门菌的DNA条带图谱相似性为96.4%,聚类分析为同一型,结合流行病学调查,初步判断菌株来自同一克隆系。结论 综合流行病学、食品卫生学和实验室检测结果,确定为一起肠炎沙门菌引起的食源性疾病,福利院应加强对特殊人群的饮食安全管理,制定相应的食源性疾病突发事件应急处理预案,防止此类事故再发生。     

Mathematical Modeling of Drying Processes of Selected Fruits and Vegetables

This study investigates the behavior of fruit and vegetable samples during drying. The experimental data are fitted to several different thin-layer drying models. Regression analysis is used to determine model parameters, while statistical indicators serve to evaluate the goodness of fit. The power function model gives the best fit for all examined samples. Based on this model, different drying and heat storage technologies can be combined to ensure that the required residual moisture content of an agricultural product is reached. It is demonstrated on the case of a specific Togolese processing plant that under favorable conditions, fossil fuel consumption can be decreased by 33 %.     

多堆厂址始发事件分析探讨

多堆厂址一级概率安全评价（PSA）研究中，机组数目的增加使得建模工作量剧增，给整个核电厂的风险评估带来困难。结合已有基础，本文研究了多堆厂址始发事件分析的筛选方法，提出利用堆芯损伤频率（CDF）上下限值评估方法，分析厂址内不同机组数对厂址CDF的影响。结果表明，双机组厂址适合优先进行具体分析。针对双机组核电站，对多堆厂址内各始发事件进行筛选。结果表明，丧失厂外电、丧失热阱等事件适合建模分析，并对其他筛选结果给出后续分析建议，为多堆厂址一级PSA后续事故序列建模工作提供了重要基础。     

Improving the shelf life stability of vacuum-packed fresh-cut peaches (Prunus persica L.) by radio frequency heating in water

The present study aimed to investigate the influence of radio frequency (RF) heating at 70 and 80 °C, in comparison with the traditional conventional heating. The RF heating technology was applied for maintaining the colour and textural quality as well as inactivating the enzymatic activity of polyphenol oxidase (PPO) and reducing the Escherichia coli growth in packaged fresh-cut peach samples. To evaluate this, 120 g of freshly cut peach fruit was placed in heat-resistant plastic bags, and 50 mL of sugar solution (12°Brix) was added to each bag and vacuum-packed for conventional heating and radio frequency (RF) heating. Our results demonstrated that the RF heating process could reduce the heating time by up to 83% at 70 and 80 °C as compared to conventional heating. Moreover, RF heating at 70 and 80 °C reduced the PPO enzymatic activity, which caused enzymatic browning, up to 85.46% and 93.5%, respectively, as compared to 40.86% reduction only for conventional heating. Furthermore, RF heating completely inhibited E. coli growth. Collectively, we demonstrated that RF heating is an emerging and promising technology for improving the quality of fresh-cut fruits such as peach during various storage conditions. The present study provides relatively novel information on the effectiveness of RF heating in maintaining the quality of fresh-cut peaches. In the future, we would like to investigate the effectiveness of RF heating on other agricultural products.