Some experimental findings in compression-after-impact (CAI) tests of CF/PEEK (APC-2) and conventional CF/epoxy flat plates

Compression-after-impact (CAI) tests have been conducted for quasi-isotropic thick plates with 48 plies by using the NASA method and on plates with 32 plies by using the SACMA method. Specimens are made of CF/PEEK (APC-2) and conventional CF/epoxy for the NASA plates and CF/epoxy for the SACMA plates. In the NASA CAI tests, the sequence of delamination buckling and its propagation is clearly revealed through various experimental techniques. One major technique is moiré topography, and the other is thermo-mechanical stress analysis with a high-accuracy infrared sensor. The arrest of delamination propagation just before catastrophic failure due to high fracture toughness is clearly captured by the moiré camera. This behavior provides good CAI values of CF/PEEK. The initial buckling properties of the delaminated region by the impact are then extensively discussed. Numerical predictions of initial buckling stress have been obtained by modelled geometry of the delaminated region simplified from its precise structure clarified by ultrasonic C-scanning. They agree fairly well with the experimental results. The in-plane stress distribution in the delaminated region before initial buckling is measured by an infrared stress graphic system. This compared favorably with finite element predictions. Two types of symmetric buckling modes with respect to the central plate surface, twin and single peak ones, are experimentally captured.     

Impact of flood alleviation schemes on aquatic macrophytes

Geomorphological, engineering and ecological surveys were carried out at 18 flood alleviation schemes in the UK to evaluate their environmental performance. As no pre-scheme river corridor surveys had been carried out at any of the sites to enable the environmental impact to be directly assessed, controls were established in natural sections adjacent to five of the engineered reaches. A space–time substitution enables the pre-scheme conditions to be estimated for comparison with the engineered reach. The physical characteristics of the channel at bankfull conditions exert a strong influence on plant community composition. Paired assessments were carried out for engineered/control reaches on five rivers and this revealed which species and habitats were most affected by various engineering treatments. The general conclusion was that dredging, widening and straightening rivers reduces the number of desirable species, whereas two-stage channels and schemes involving the construction of flood banks at the edge of the meander belt maintained the richness and preserved and enhanced the occurrence of key species. Data from every cross-section, engineered and control reaches, enabled a model to be developed relating species occurrence to physical habitat features. This can be used to predict, at the stage of appraisal or design of a project, the likely response of the river to any particular engineering works. Given information on the existing condition in the river, it enables the environmental impact of the scheme, in terms of its effect on river bed plant species, to be assessed.     

中国造纸产品的生命周期分析

采用生命周期清单分析方法分析了我国造纸产品生产过程中的物料消耗,能源消耗以及对环境的排放,研究表明,造纸生命周期过程中值得关注的环境问题有:能源消耗高于发达国家;水循环利用率较低,造成水资源浪费;废纸回收率有待提高;废水污染严重,成为限制造纸工业快速发展的瓶颈;同时固体废弃物的排放也将造成严峻的环境问题.     

深冷常压液氨储存系统的环境影响

深冷、平底、常压液氨储罐是目前大型氨厂、港口吞吐储存的最佳方法,也是极安全的设施,该文叙述这种液氨储罐设施系统的运行工艺概况,储罐维护保养,以及如何放空、事故或泄漏等原因所致的环境影响降至最低的措施。     

橡胶坝蓄水工程对城市浅层地下水环境影响的评价

在查清浅层地下水含水层组合情况后,通过实测资料对比分析了南阳市白河第三橡胶坝蓄水前后地下水开采量、地下水动态变化规律、地下水降落漏斗演变趋势、地下水水质情况、环境地质现象等问题。指出蓄水前,地下水环境处于不断恶化的过程中;浅层地下水超采严重致使市中心城区缺水严重;地下水位持续下降,在白河南北形成了2个降落漏斗并不断扩大;水质恶化,局部地段出现地裂缝,膨胀土地区低层建筑物墙体开裂等。蓄水后,在库水范围内白河侧渗底渗量增大,增大了浅层地下水的补给量,地下水动储量增大,大大缓解了市中心城区的缺水现状;在地下水开采量不断增大的情况下,漏斗中心的地下水位回升,并趋于动平衡状态;除橡胶坝下游、白河左岸1000m及右岸600m等处外,漏斗内的其它部位水质变好,地下水环境明显得到改善。但同时地下水位上升使某些建筑物地下室进水及需对拟建建筑物深基坑降水,给工程建设带来了一些不利影响。     

加入世贸组织对我国石化行业的影响与对策

本文详细分析了加入ＷＴＯ对我国石化行业的正反两面影响,并提出几点应对建议。     

Evaporative cooling: An assessment of california market potential and estimated impacts of key deployment barriers

The California Energy Commission has recognized evaporative cooling space conditioning as a key demand-side “Opportunity Technology,” which offers compelling energy, economic development and environmental benefits to the state. In 1993, the Commission lead an effort to form an industry Collaborative of Stakeholders whose primary focus was to improve market penetration through the identification and elimination of the key barriers to technology deployment. More recently, the Commission has supported this objective through the funding of a statewide market assessment of evaporative cooling in the residential and commercial market segments with Regional Economic Research, Inc. of San Diego, California under Contract No. 500-93-027. Summary data and results from this work are presented in this paper.Baseline forecasts of market shares and the associated energy impacts within the residential and commercial market segments, including new construction and existing facilities, were then developed for each statewide planning area and utility climate zone in California. Thereafter, forecasts of the sensitivity of market shares and energy impacts to changes in key drivers (e. g., awareness, technology costs, and select non-economic drivers) were generated to establish the relative importance of each of the technology market drivers. Finally, Achievable Potential was estimated in the form of market shares and associated energy savings, based upon assumptions with respect to the achievable reductions in evaporative cooling deployment barriers.     

Impoverishment of YOY‐fish assemblages by intense commercial navigation in a large Lowland river

Navigation‐induced physical forces have been suggested to modify the structure of riverine fish assemblages by impeding especially the recruitment of littoral bound species. To investigate the effect of vessel frequency on fish, we compared the composition and seasonal succession of young‐of‐the‐year (YOY) fish assemblages in three similarly degraded river reaches differing in average vessel passages (2, 6 and 41 per day). Fish were caught by electrofishing biweekly between May and September. Multivariate tests were used to analyse differences between YOY‐fish assemblages and hurdle regression models applied to determine abiotic factors predicting fish occurrence and abundance. Roach (Rutilus rutilus) and perch (Perca fluviatilis) densities were compared. Roach larvae remain in the littoral zone while perch larvae shift to the pelagic zone immediately after hatch. YOY‐fish assemblage structure substantially changed along the traffic intensity gradient. In the high traffic intensity reach, species number and total fish density were markedly reduced compared to the other reaches. Roach densities were lowest in the high traffic intensity reach whereas perch densities did not decline along the gradient. Hurdle regressions confirmed a stronger effect of commercial navigation traffic intensity on roach than on perch. The total zooplankton biomass was highest in the high traffic intensity reach. Our results provide empirical evidence that intensive commercial navigation impoverishes fish assemblages in width‐restricted waterways. They underlined that in particular those species that have their first nursery habitats in shoreline areas were more affected by intensive commercial navigation than species whose larvae live predominantly pelagic. The results indicate that the negative effect of intensive navigation on riverine fish results primarily from the navigation‐induced hydraulic disturbances along the banks. Therefore, mitigation of navigation‐induced hydraulic forces is required to prevent degradation of fish communities in waterways. Copyright © 2010 John Wiley & Sons, Ltd.