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Unsteady Cavitation Analysis Using Phase Averaging and Conditional Approaches in a 2D Venturi Flow

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Open Journal of Fluid Dynamics 2013年第3期3卷 171-183页

作者： Vincent Aeschlimann Stéphane Barre Henda Djeridi LAMH Université Laval Quebec Canada LEGI UMR 5519 Grenoble France lpo UMR 6523 Brest France

The present study refers to a cavitating Venturi type section geometry characterized by a convergent angle of 18°?and a divergent angle of about 8°?where the sheet cavity presents typical self-oscillation behavior with quasi-periodic vapor clouds shedding. This work is an extension of previous works concerning void ratio measurements and velocity fields using double optical probe and constitutes a complete analysis of the two-phase structure of unsteady cavitating flow. This paper provides a new method based on conditional and phase averaging technique with wall pressure signal to treat experimental data in order to evaluate more precisely time-averaged and rms values of the void ratio and instantaneous velocity fields. Conditional analysis shows a different behavior of the two-phase flow dynamics leading to highlight high void ratio events linked to the break-off cycle. Unsteady phase averaging of the optical probe signal gives the evolution of the void ratio at each studied location in the venturi and shows that the fluctuations close to the wall (where the re-entrant jet is predominant) are in phase with the upper part of the cavity instead of the thickness of the cavity which is unchanged.

关键词： Unsteady Cavitation Sheet Cavity Optical Probes Venturi-Type Flow Turbo Pump

Characterization of volatiles Tribolium castaneum(H.)in flour using solid phase microextraction–gas chromatography mass spectrometry(SPME–GCMS)

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Food Science and Human Wellness 2016年第1期5卷 24-29页

作者： Yonghao Niu Giles Hardy Manjree Agarwal Lei Hua Yonglin Ren College of Plant Protection Northwest A&F UniversityYanglingShaanxi 712100China School of Veterinary and Life Sciences Murdoch University90 South StreetMurdochWA 6150Australia Australia Cooperative Research Centre for National Plant Biosecurity LPO Box 5012BruceACT 2617Australia

The objective of this study was to identify volatile organic compounds(VOCs)from flour,Tribolium castaneum(Herbst)and flour infested by T.castaneum separately,to confirm the difference of healthy flour and flour infested by T.castaneum and to explore the new technique to diagnose stored flour’s quality by its VOCs change.Headspace-solid phase microextraction(HS-SPME)coupled with gas chromatography(GC)and gas chromatography–mass spectrometry(GC–MS)were used to detect the VOCs of three different samples.Totally,71 different compounds were identified in flour,T.castaneum and T.castaneum infested flour.Therefore,27 VOCs were identified from flour alone,32 VOCs from T.castaneum and 39 VOCs from T.castaneum infested flour.The compound 2-ethyl-2,5-cyclohexadiene-1,4-dione is only found in T.castaneum infested flour.This suggests that 2-ethyl-2,5-cyclohexadiene-1,4-dione can be a useful VOC for detecting T.castaneum in flour.

关键词： mass phase solid

A Process Study of the Tidal Circulation in the Persian Gulf

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Open Journal of Marine Science 2012年第4期2卷 131-140页

作者： Stéphane Pous Xavier Carton Pascal Lazure DYNECO IFREMER Brest France LOCEAN/IPSL Université Pierre et Marie Curie Paris France lpo/IUEM Université de Bretagne Occidentale Brest France

A homogeneous shallow-water model with free surface is used to model the tidal circulation in the Persian Gulf. The numerical finite-difference model includes harmonic diffusion of horizontal momentum and quadratic bottom friction, it has a 9 km mesh size and it is forced by 7 tidal components at its southern boundary. High precision bathymetric data are used to obtain the bottom topography. The numerical model is run for more than a year. The results are the following: 1) The model accurately reproduces the tidal phase and amplitude observed at 42 tidal gauges in the region. This accuracy is attributed to the presence of the 7 components which are able to interact nonlinearly;2) The amphidromic points are also well positioned by the model due to a proper choice of bathymetry. This was checked also with a simpler geometry of the domain;3) The tidal currents can be strong in the Straits of Hormuz and in shallow areas;thus they will have an effect of the hydrology of the region. The residual currents are weak so that they will be negligible for the large-scale circulation on long periods;4) Finally, the sea-surface elevation forecast by the model is in close agreement with in-situ measurements of pressure in the Straits, performed during the GOGP99 experiment.

关键词： Persian Gulf Barotropic Tide Hydrodynamical Modeling Comparison with Data

氰(C_2N_2)在3种类型土壤中的吸附与消解动态

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农业环境科学学报 2013年第1期32卷 75-80页

作者：李保同 Ren Yonglin 曾鑫年江西农业大学农学院南昌330045 华南农业大学农药与化学生物学教育部重点实验室广州510642 Cooperative Research Centre for National Plant Biosecurity LPO Box 5012 Bruce ACT 2617 Australia

氰(C2N2)是一种具有替代溴甲烷潜力的新熏蒸剂,明确C2N2在3种类型土壤(沙质土、壤土和粘质土)中的吸附行为与消解动态对C2N2的安全应用与风险评估具有重要的意义。采用静态平衡法研究了C2N2在3种类型土壤中的吸附与挥发行为,采用溶剂顶... 详细信息

氰(C2N2)是一种具有替代溴甲烷潜力的新熏蒸剂,明确C2N2在3种类型土壤(沙质土、壤土和粘质土)中的吸附行为与消解动态对C2N2的安全应用与风险评估具有重要的意义。采用静态平衡法研究了C2N2在3种类型土壤中的吸附与挥发行为,采用溶剂顶空法测定了C2N2在3种类型土壤中的消解动态。结果表明,土壤对C2N2具有较强的吸附能力,熏蒸4h,85%以上的C2N2被土壤吸附,熏蒸12h,98%以上的C2N2被土壤吸附,其吸附强度为粘质土>壤土>沙质土。熏蒸期间C2N2在沙质土、壤土和粘质土配气瓶内消退较快,熏蒸48h的消退率分别为94.12%、96.70%和98.27%。同时,C2N2在土壤中可快速转化产生HCN,熏蒸后1h达到最大值,其浓度为粘质土>壤土>沙质土,而后快速下降。通风后C2N2及其转化产物HCN在土壤中易于挥发和消解,C2N2和HCN在3种类型土壤中的挥发速率相近,在沙质土、壤土和粘质土中C2N2的消解半衰期分别为15.82、14.56h和12.43h,HCN分别为17.52、20.82h和24.27h。

关键词：氰(C2N2) 氰化氢(HCN) 吸附消解动态土壤

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氰在土壤中的吸附与转化

土壤学报 2013年第2期50卷 237-243页

氰(C2N2)是一种具有替代溴甲烷潜力的新熏蒸剂,明确C2N2在土壤中的吸附与转化行为对C2N2的安全应用具有重要的意义。利用静态法研究了C2N2在土壤中的吸附与转化过程,土壤对C2N2的吸附速率与土壤的理化性质有关,受环境温度、土壤含水量... 详细信息

氰(C2N2)是一种具有替代溴甲烷潜力的新熏蒸剂,明确C2N2在土壤中的吸附与转化行为对C2N2的安全应用具有重要的意义。利用静态法研究了C2N2在土壤中的吸附与转化过程,土壤对C2N2的吸附速率与土壤的理化性质有关,受环境温度、土壤含水量和土壤生物的影响较少,与熏蒸浓度无关。采用气相色谱(GC)和流动注射分析仪(FIA)测定了土壤对C2N2的吸附率和C2N2在土壤中的可能转化产物。结果表明,土壤对C2N2的吸附能力很强,熏蒸2 h吸附率在75%以上,熏蒸24 h吸附率在98%以上,并可快速转化为HCN、NH4+和NO3-。其中,大约20%的C2N2转化为NH4+和NO3-,13%的C2N2转化为HCN。熏蒸48 h未检测到NO2-。HCN在土壤中不稳定,可进一步转化为其他含氮化合物。

关键词：氰(C2N2) 熏蒸剂转化土壤氰化氢(HCN)

吹扫捕集法测定粮食中熏蒸剂氰与氰化氢残留量

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中国粮油学报 2013年第3期28卷 113-116,128页

作者：李保同曾鑫年 Ren Yonglin 江西农业大学农学院南昌330045 华南农业大学农药与化学生物学教育部重点实验室广州510642 Cooperative Research Centre For National Plant Biosecurity LPO Box 5012BruceACT 2617Australia

采用吹扫捕集气相色谱法建立了熏蒸剂氰和氰化氢在粮食(玉米、高粱、稻谷、小麦和大麦)中的分析方法,对粮食中氰和氰化氢预处理的吹扫温度、吹扫载气(N2)流量和吹扫时间等参数进行了优化,分析了吹扫捕集气相色谱测定的回收率、精密度、... 详细信息

采用吹扫捕集气相色谱法建立了熏蒸剂氰和氰化氢在粮食(玉米、高粱、稻谷、小麦和大麦)中的分析方法,对粮食中氰和氰化氢预处理的吹扫温度、吹扫载气(N2)流量和吹扫时间等参数进行了优化,分析了吹扫捕集气相色谱测定的回收率、精密度、检出限和定量限等质量控制参数,并测定了实际熏蒸粮食中氰及其降解产物氰化氢残留量。结果表明,用50%磷酸溶液作溶剂,吹扫温度80℃、吹扫载气(N2)流量40 mL/min和吹扫时间90 min为最佳的吹扫方法参数。采用该方法测定粮食中氰和氰化氢的加标回收率分别为90.88%～96.25%和91.17%～95.83%,相对标准偏差(RSD)分别为0.36%～5.55%和0.90%～6.24%(n=6),检出限(LOD)分别为0.003 6 mg/kg和0.005 3 mg/kg(S/N=3),定量限(LOQ)分别为0.012 0 mg/kg和0.017 7mg/kg(S/N=10)。用吹扫捕集法检测熏蒸粮食中氰其降解产物氰化氢的残留量与溶剂顶空法测定结果相一致。

关键词：粮食氰(C2N2) 氰化氢(HCN) 熏蒸剂吹扫捕集气相色谱

大亚湾核电基地变压器的火灾预想与消防运行研究

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科技视界 2016年第11期 293-293,309页

作者：程友传李纯贺大亚湾核电运营管理有限责任公司运行二部lpo 广东深圳518124 大亚湾核电运营管理有限责任公司安全防护部OSE 广东深圳518124

本文分析了核电厂典型的变压器火灾模式,并针对其特点从设计、建造、运行和维护需求出发,分析和评价变压器的火灾风险以及消防措施。同时,结合大亚湾核电厂和岭澳核电厂变压器的消防现实情况,提出消防运行建议。

关键词：核电消防变压器安全可靠