Temporal trends in agricultural water use and the relationships to hydroclimatic factors in the High Plains aquifer region

The High Plains aquifer (HPA) is the primary water source for agricultural irrigation in the US Great Plains. The water levels in many locations of the aquifer have declined steadily over the past several decades because the rate of water withdrawals exceeds recharge, which has been a serious concern to the water resources management in the region. We evaluated temporal trends and variations in agricultural water use and hydroclimatic variables including precipitation, air temperature, reference evapotranspiration, runoff, groundwater level, and terrestrial water storage across the HPA region for different periods from 1985 to 2020 at the grid, county, or region scale. The results showed that water withdrawals decreased from 21.3 km³/year in 1985 to 18.2 km³/year in 2015, while irrigated croplands increased from 71,928 km² in 1985 to 78,464 km² in 2015 in the entire HPA. The hydroclimatic time-series showed wetting trends in most of the northern HPA, but drying and warming trends in the southern region from 1985 to 2020. The groundwater level time-series indicated flat trends in the north, but significant declining in the central and southern HPA. Trends in irrigation water withdrawals and irrigation area across the HPA were controlled by the advancement of irrigation systems and technologies and the management of sustainable water use, but also were affected by dynamical changes in the hydroclimatic conditions.     

基于响应曲面法的遗煤自燃分析与研究*

为研究高瓦斯易自燃煤层不同供风量、高抽巷抽采流量、低抽巷抽采流量3因素对采空区自燃“三带”分布影响规律，选取阳煤五矿8406工作面为研究对象，在数值模拟研究基础上，采用Design Expert软件进行Box Behnken试验设计，构建采空区氧化升温带宽度在3因素、3水平条件下的二次回归响应曲面模型，并对不同条件下采空区氧化升温带宽度进行预测与分析。结果表明:二次回归方程P值为0.001 6，预测模型显著，模型的失拟项为0.606 3，不显著，回归方程具有统计学意义；当供风量为1 500~2 000 m3/min，低抽流量为450~650 m3/min，高抽流量为100~200 m3/min时，对氧化升温带宽度一次项重要度排序为C（高抽巷抽采流量）>A（供风量）>B（低抽巷抽采流量），二次项重要度排序为AC（供风量和高抽巷抽采流量）>AB（供风量和低抽巷抽采流量）>BC（低抽巷抽采流量和高抽巷抽采流量），且AB,AC,BC之间均无交互作用。     

研究冷却塔噪声环境影响评价及污染防治措施

随着我国社会经济的发展速度不断加快,城市化建设层次越来越高,大量中央空调设备的冷却塔噪声影响到了人们的日常生活质量。基于此,本文重点针对冷却塔噪声环境的影响进行了分析和研究,提出了相关的有效防治策略,以此有效提高人们的生活质量和舒适度。     

道路交通噪声预测声源简化研究

为了分析《环境影响评价技术导则声环境》(HJ 2.4—2009)中将道路声源简化为1条位于道路中心线处的线声源与按照车道数简化为多条线声源之间的误差,针对不同宽度的道路,推导了多条线声源与1条线声源在接收点噪声影响的误差计算公式,并基于Predictor-lima预测软件预测和现场噪声衰减规律实测进行了验证。研究结果表明,对于接收点到道路边缘的距离大于道路宽度的情况,可简化为1条线声源;对于接收点到道路边缘的距离小于道路宽度的情况,应按照车道数简化为多条线声源。     

浅谈县级环境监测质量管理工作现状及对策

当前环保系统垂直改革稳步推进,县级环境监测质量管理工作也迎来新的机遇与挑战。从县级环境监测站质量管理工作现状着手,分析新形势下存在质量管理体系有效性缺乏、现场监测过程质量管理薄弱、质量管理意识尚待提高等问题。提出,应从加强体系建设、提高现场监测水平、强化考核培训力度等方面改进县级环境监测质量管理工作水平。     

洪泽湖水体富营养化时空分布特征与影响因素分析

通过2014年—2017年对洪泽湖12个水质断面定期调查,采用营养状态指数(TLI)综合评价其水体富营养状态,同时应用主成分分析方法(PCA)分析其富营养化状态的时空变化特征。结果表明,洪泽湖70%以上的调查断面水质全年处于轻度富营养化状态,夏季是其富营养化最严重的季节;洪泽湖年内水体水质差异较大,而其水华特征并未呈现明显差异;洪泽湖富营养化很大程度上受制于营养盐的积累程度,并与湖泊透明度呈现极显著的负相关关系(p0.001),与湖水pH值呈现极显著的正相关关系。     

水质氨氮在线监测仪对污染源低浓度样品测定的研究

水质氨氮在线监测仪广泛用于各类水体中氨氮的在线监测,随着我国水质氨氮减排工作的开展,污染源废水中氨氮浓度逐渐降低,目前市场上的水质氨氮在线监测仪是否适用于低浓度氨氮样品的在线监测成为广大环保工作者关心的问题。选取3种不同类型的水质氨氮在线监测仪分别进行低浓度标样和实际水样测试,并对结果进行了讨论。     

组织支持感对建筑业农民工不安全行为的影响*

为对建筑业农民工的不安全行为进行科学有效的管理，探讨组织支持感、自我效能感与建筑业农民工不安全行为之间的关系，防止因建筑业农民工不安全行为造成的不安全事件发生，从组织行为学和计划行为学视角出发，以218名一线建筑业农民工为研究对象，通过构建结构方程模型进行实证分析。结果表明:组织支持感的3个维度均可直接对建筑业农民工的不安全行为产生负向显著影响，其中关心利益维度影响最大，工作支持维度次之；建筑业农民工的自我效能感在其组织支持感与不安全行为的负向关系中起到中介作用。     

A path analysis model for explaining unsafe behavior in workplaces: the effect of perceived work pressure

Background. Unsafe behavior is closely related to occupational accidents. Work pressure is one the main factors affecting employees’ behavior. The aim of the present study was to provide a path analysis model for explaining how work pressure affects safety behavior. Methods. Using a self-administered questionnaire, six variables supposed to affect safety employees’ behavior were measured. The path analysis model was constructed based on several hypotheses. The goodness of fit of the model was assessed using both absolute and comparative fit indices. Results. Work pressure was determined not to influence safety behavior directly. However, it negatively influenced other variables. Group attitude and personal attitude toward safety were the main factors mediating the effect of work pressure on safety behavior. Among the variables investigated in the present study, group attitude, personal attitude and work pressure had the strongest effects on safety behavior. Conclusion. Managers should consider that in order to improve employees’ safety behavior, work pressure should be reduced to a reasonable level, and concurrently a supportive environment, which ensures a positive group attitude toward safety, should be provided. Replication of the study is recommended.     

燃机电厂噪声模拟时SoundPLAN声源模型的简化

燃机电厂一般靠近用电负荷或城镇建设，为了有效地控制噪声，在燃机电厂项目的设计、环评等阶段对其噪声影响进行合理的模拟从而提出相应的降噪方案是非常必要的。结合国家标准，对燃机电厂的敏感目标和主要噪声的声源特性进行了总结。通过对比声源类型、中心频率的设置对模拟结果产生的影响，探讨了在应用SoundP-LAN软件对燃机电厂的噪声模拟时如何简化设置声源模型的问题，为今后的噪声模拟评估工作提供参考。