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911.
912.
In this study, biofiltration using a natural wood chip medium and a commercial biofiltration medium was evaluated for the removal of moderate concentrations of hydrogen sulfide (H2S) (up to 100 parts per million by volume [ppmv]) in the presence of significant concentrations of ammonia (NH3). These levels were chosen as representative of wastewater lift station emissions in the Brownsville, TX, area. NH3-removing portions of the biofilms may compete with H2S-removing portions and inhibit H2S removal. H2S process removal efficiencies for the commercial and natural media ranged from 90 to 96% depending on inlet loading and media type and bed height. Kinetic analysis of the H2S removal process followed apparent first-order reaction behavior. The average first-order reaction rates were 0.03 sec(-1) for the commercial medium and 0.09 sec(-1) for the natural medium. Pressure drops across the columns ranged from 0.41 in. H2O/ft for the commercial medium to 1.41 in. H2O/ft for the natural medium. NH3 gas levels of up to 80 ppmv did not affect the H2S removal process efficiency, and calculated kinetic rate constants for H2S removal remained almost the same. The NH3 gas also was removed simultaneously with the H2S up to 98% removal efficiency by the commercial medium.  相似文献   
913.
914.
结合红树林景观特征,评价广西壮族自治区红树林典型分布区(珍珠湾、茅尾海、丹兜海)的生态系统健康状况。通过对不同景观格局与过程的指标进行分析,筛选出面积周长比分维数(PAFRAC)、中高级重要性斑块比例、等效面积概率连接度指数(ECA)指标来表征景观特征,并进一步结合水环境、生物残毒、栖息地和生物现状构建生态健康评价模型。结果表明:珍珠湾和丹兜海景观破碎化程度较小,茅尾海景观破碎化程度相对较高;珍珠湾、茅尾海、丹兜海的ECA依次为0.82×10~7、0.76×10~7、0.59×10~7,但丹兜海的重要栖息地斑块分布最多。对比分析表明,耦合了景观指数的生态系统健康评价结果符合实际,珍珠湾和丹兜海均处于健康状态,而茅尾海处于亚健康状态。  相似文献   
915.
Objective: Drivers’ behaviors such as violations and errors have been demonstrated to predict crash involvement among young Omani drivers. However, there is a dearth of studies linking risky driving behaviors to the personality of young drivers. The aim of the present study was to assess such traits within a sample of young Omani drivers (as measured through the behavioral inhibition system [BIS] and the behavioral activation system [BAS]) and determine links with aberrant driving behaviors and self-reported crash involvement.

Methods: A cross-sectional study was conducted at the Sultan Qaboos University that targeted all licensed Omani's undergraduate students. A total of 529 randomly selected students completed the self-reported questionnaire that included an assessment of driving behaviors (e.g., Driver Behaviour Questionnaire, DBQ) as well as the BIS/BAS measures.

Results: A total of 237 participants (44.8%) reported involvement in at least one crash since being licensed. Young drivers with lower BIS–Anxiety scores and higher BAS–Fun Seeking tendencies as well as male drivers were more likely to report driving violations. Statistically significant gender differences were observed on all BIS and BAS subscales (except for BAS–Fun) and the DBQ subscales, because males reported higher trait scores. Though personality traits were related to aberrant driving behaviors at the bivariate level, the constructs were not predictive of engaging in violations or errors. Furthermore, consistent with previous research, a supplementary multivariate logistic regression analysis revealed that only driving experience was predictive of crash involvement.

Conclusions: The findings highlight that though personality traits influence self-reported driving styles (and differ between the genders), the relationship with crash involvement is not as clear. This article further outlines the key findings of the study in regards to understanding core psychological constructs that increase crash risk.  相似文献   

916.
随着国家“一带一路”倡议的推进,越来越多中国企业“走出去”,拓展海外市场。相关方作为海外项目安全管理的重点,存在数量多、安全管理能力参差不齐、安全管理难度大等特点。万宝矿产有限公司从相关方准入审核、过程管控、考核淘汰等全生命周期对海外项目各相关方进行规范化管理,提升了相关方安全管理水平,避免了生产安全事故,保障了项目顺利进行。  相似文献   
917.
918.
全球变化对区域土地持续利用的影响表现为其多方面内容从不同侧面直接或间接地对区域土地利用生产性、安全性、保持性、可行性和接受性产生影响。在长江三角洲地区 ,全球变化对土地持续利用的影响主要表现为不利的方面 :( 1)海平面上升导致土地面积减少及土壤性质恶化 ;( 2 )自然灾害增多导致土地利用安全性降低 ;( 3)酸雨危害加重导致土地生态环境恶化 ;( 4 )地表植被减少及湿润指数降低导致土地退化加剧。针对以上问题 ,应采取以下对策以促进长江三角洲土地持续利用 :( 1)加强全球变化监测与预警 ;( 2 )制定适应于全球变化的土地持续利用规划 ;( 3)增强土地利用对全球变化的应变能力 ;( 4 )加强全球合作 ,减缓不利于人类生存的全球变化速度。  相似文献   
919.
Back in 1992, the Gulf of Aqaba Environmental Action Plan (GAEAP), a collaboration between the Aqaba Region Authority (ARA), Jordan and the World Bank, gave considerable emphasis to the environmental protection of the Gulf of Aqaba [The World Bank. Gulf of Aqaba Environmental Action Plan. Report No. 12244JO (1993).]. The document recommended the establishment of a marine reserve and the long term monitoring of the coastal habitats' environmental quality. The combination of a dedicated follow up, the collaborative efforts of ARA and the Marine Science Station (MSS), and the founding of the Aqaba Special Economic Zone Authority (ASEZA) have turned the recommendations into reality. A comprehensive monitoring program of the Jordanian coastal habitats commenced in 1999. The first three years of the program were financed by a donation from The Global Environmental Facility (GEF). In return, Jordan has committed itself to the maintenance of the monitoring program as an ongoing tool for sustainable coastal management. The monitoring program includes observations on benthic habitat, fish communities, bottom sediments and seawater quality. This paper focuses on the results of seawater-quality monitoring in the first three years. Records of weather conditions, coastal currents, seawater temperature, transparency, salinity, density, pH, alkalinity, dissolved oxygen, ammonia, nitrate, nitrite, phosphate, silicate, particulate matter, chlorophyll a, zooplankton biomass, total coliform, fecal coliform, hydrocarbons and sedimentation rate have been generated monthly since January 1999 at six coastal stations, and one offshore reference station, in the Jordanian waters of the Gulf of Aqaba. The coastal stations are located at sites with different benthic habitats and are occupied by different human activities. Offshore records of density (thermohaline structure), nutrients and chlorophyll a depicted two well-defined seasons; a nutrient-/chlorophyll a-rich, mixed water winter from December to April and a nutrient-/chlorophyll a-poor, stratified water summer from June to October. Short transition seasons appeared in May and November. The mixing and stratification seasons were also clearly depicted in the coastal waters. Statistical analysis of the three-year data collected at the offshore station revealed no significant inter-annual differences in the upper 125 m of the water column with respect to any of the measured parameters. At coastal stations, the water quality at the two northernmost stations was significantly different in comparison to the upper 125 m at the offshore station and to the other coastal stations, with respect to the two key indicator parameters: inorganic nitrogen and chlorophyll a. The three-year findings of the monitoring program are employed to suggest standard codes of reference for the coastal water quality.  相似文献   
920.
山东各地市经济发展环境评价研究   总被引:5,自引:0,他引:5  
为评价山东各地市的经济发展环境。采用《2003山东统计年鉴》中的数据及专家打分资料进行因子分析,得出由地市经济运行环境、地市社会发展环境、地市制度政策环境、地市自然环境和地市资源环境五部分构成的地市经济发展环境评价指标体系。并根据评价得分。将山东各地市划分为3个梯度:(1)青岛、济南得分在0.7以上,为第一梯度,有良好的地市经济发展环境;(2)淄博、东营、烟台、威海、潍坊得分在0分以上。为第二梯度,经济发展环境较好;(3)其他地市为第三梯度。经济发展环境较差。文章最后分别对各梯度地市提出改善经济发展环境的策略。  相似文献   
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