几种压力容器在役监控技术及应用

介绍了若干压力容器在役监控技术的实例。声发射技术和超声检测是比较可行的监控技术。     

Rehabilitation of a lowland river: Reconciling flood defence with habitat diversity and geomorphological sustainability

Geomorphologically appropriate rehabilitation measures were proposed to enhance the in-stream environment of the lowland River Idle, north Nottinghamshire, UK. However, the River Idle has multi-functional management requirements including those of flood defence so environmental enhancement must be pursued without significantly increasing the flood risk. Hydraulic testing of rehabilitation proposals is complicated because of the stringent assumptions about flow and morphology in ‘traditional’ hydraulic models. While new generation two- and three-dimension hydraulic models may overcome some of these problems, they are extremely data intensive, require advanced modelling capabilities and are, therefore, very expensive to apply. Also, they do not yet predict morphology-flow interactions adequately. As an alternative, several simple hydraulic models were applied to test the rehabilitation proposals, based on a fitness-for-purpose criterion.BENDFLOW was applied to fine tune the optimal siting of measures and to estimate the additional near-bank scour generated by proposed bend re-profiling. HMODEL2 and the FCFA method were used to test the impact on local channel conveyance capacities and HECRAS was applied to simulate the impact of the proposals on regional flood defence. Indicative results from the testing suggested a maximum increase in near-bank scour of 0·15 m in re-profiled bends, a loss of approximately 10% in flood conveyance locally due to deflector installation or reed and tree planting, and a 0·12 m increase in flood stage within the reach for a 15 year flood. The modelling results were acceptable to the management authority as an indication of an acceptable compromise between flood defence and conservation interests, and construction of the measures followed in 1996. It is clearly that it will require the results of post-project monitoring to indicate whether compromises made to the rehabilitation initiatives in order to satisfy flood defence requirements have unduly reduced their environmental enhancement potential but, for assessing the proposed methods, the models are recommended for use other lowland river environments.     

Evaluating the impacts of global environmental assessments

There are currently no widely accepted procedures for comparing the performance of global environmental assessments (GEAs) and this may be a barrier to improving their methodology. To encourage greater self-reflection within the GEA community, it is proposed to introduce consistent evaluation approaches. Two elements from current evaluation practice are reviewed here that could be particularly useful for evaluating GEAs. The first are logic models which provide a transparent visual mapping of how activities in a GEA are intended to have impacts on policies. The second are performance metrics. It is proposed that GEAs adopt two kinds of metrics: (i) A common generic set for use in all GEAs to provide a basis for comparing the performance of GEAs, and (ii) a specific set of measureable metrics for each particular GEA derived from/linked to the generic set. Although many issues arise in applying these and other elements from evaluation theory and practice to GEAs, the potential benefits are greater comparability of GEA performance and new knowledge about how to improve them. This Short Communication is part of a Special Issue on solution-oriented GEAs.     

测土配方施肥对油菜生产的影响——基于1 722份田间试验材料的经济学分析

论文基于1 722份田间试验数据,将氮、磷、钾肥的投入量和油菜的产出量分别折算为相应的具体投入值和产出值,首先,运用超越对数生产函数模型计算出各种化肥要素的边际产出,研究发现氮、磷、钾肥的投入对油菜产出值的作用大小存在一定差异,对油菜产出值的影响大小关系为氮肥>磷肥>钾肥,其中氮肥的产出弹性值为0.288 3,磷肥的产出弹性值为0.180 3,钾肥的产出弹性值为0.087 7。其次,继续探究氮、磷、钾肥在油菜生产中的相互关系,结果显示,氮肥替代弹性系数为-0.058 8,磷肥为0.120 9,钾肥为0.281 0。最后,测算出使油菜产出值最大的氮肥最佳投入值为951.20 元/hm²,最佳磷肥投入值为3 766.08 元/hm²,最佳钾肥投入值为621.32 元/hm²。     

松散煤体渗流传热试验装置研制

为研究松散煤体低温氧化及通风供氧下的渗流传热规律,研发了渗流传热试验装置。试验装置由气体加湿系统、气体加热系统、煤样反应系统、数据采集系统和安全保护系统组成;本装置可实现自动加湿、控温、自动采集数据及处理数据。为解决装置使用和运行中的安全问题,设计了断电保护、有害气体检测等措施,保障试验装置的安全、可靠。     

立井揭煤前测定煤层瓦斯压力的方法与实践

为了解决复杂环境下立井揭煤前煤层瓦斯压力的可靠测定,基于揭煤井筒瓦斯地质特征、煤岩体物理力学性质,应用COMSOL软件模拟揭煤工作面在接近目标煤层时,井筒周围煤岩的地应力分布特征,直观展现了目标煤层中的应力分布结果。模拟结果表明,立井工作面距煤层的垂直距离为7 m时,煤层中会形成一个近似于环形的卸压圈,卸压半径为16 m,因此煤层瓦斯压力测试孔的终孔位置应布置在井筒中心线16 m以外的原始地应力区,以保证测压点瓦斯压力不受揭煤井筒卸压区的影响,令测压结果准确可靠,从而更好地预测煤与瓦斯突出区域的危险性。同时,结合立井揭煤工作面的水文地质特征和井筒严重淋水情况,自主研发并应用了瓦斯测压孔"两堵一注"封孔材料及特定的封孔工艺,进一步保障了封孔质量和瓦斯压力测试结果的可靠性。最后,依据测压结束时测压管内的实际水压情况,对测压结果进行修正,并依据实测瓦斯含量,采用间接法对所测得的瓦斯压力进行验证,实测值在反算得到的瓦斯压力值域内,表明此方法有效可行。     

Are you okay to drive? Commuting behavior and blood alcohol concentrations among restaurant diners

Objective: Drink driving is widely recognized as a major road safety problem. In Australia, health promotion messages encourage monitoring the number of standard drinks consumed prior to driving. This pilot research aimed to investigate commuting behavior and blood alcohol concentration (BAC) of diners, including intended drivers, at Sunshine Coast restaurants.

Methods: Five hundred and forty-four diners (n = 260 males) consented to participate in a brief interview and to use a breathalyzer device to measure their BAC.

Results: Forty percent of participants advised they don't drink and drive (34% of males, 45% of females; 67.25% of <17–20 years, 30.5% of 50–59 years), and of the remaining participants, 75% advised they count the number of their drinks (69% of males, 84% of females; 32% of <17–20 years, 82% of 50–59 years), while 10% of participants monitored their BAC by how they were feeling (12% of males, 6% of females). Thirty-seven percent of participants said it was easy/very easy to estimate their BAC (41% of males; 33% of females; 21% of <17–20 years, 43% of 50–59 years). The actual BAC was less than expected for 56% of participants, with one-third underestimating BAC and some intended drivers having an actual BAC in excess of the 0.05 limit.

Conclusions: Given the proportion of diners who reported they count the number of drinks, or use feelings as a way to gauge BAC, coupled with the considerable proportion who underestimated their BAC, a safer public health message is to avoid driving if you intend to drink. In addition, targeted intervention for experienced drivers (and, arguably, drinkers) appears warranted, as every participant aged less than 21 years who stated he or she would drive home indeed had a zero BAC. Interestingly every female driver who stated she would be driving home also had a legal BAC, suggesting gender-specific intervention.