Parental phenols exposure and spontaneous abortion in Chinese population residing in the middle and lower reaches of the Yangtze River

Widespread use of phenols has led to ubiquitous exposure to phenols. In experimental animals, phenols increased resorptions, reduced live litter size and fetal body weights. However, there are limited epidemiological evidences of the relationships between exposure to phenols and pregnancy outcomes. We evaluated the associations between parental urinary levels of various phenols and spontaneous abortion in a Chinese population residing in the middle and lower reaches of the Yangtze River. A case-control study was conducted that included 70 case couples with medically unexplained spontaneous abortion and 180 control couples who did not have a history of spontaneous abortion and had at least one living child. Both parental urinary phenols were measured by ultra-high performance liquid chromatography-tandem mass spectrometry including bisphenol A (BPA), benzophenone-3 (BP-3), 2,3,4-trichlorophenol (2,3,4-TCP), pentachlorophenol (PCP), 4-n-octylphenol (4-n-OP) and 4-n-nonylphenol (4-n-NP). Compared with the low exposure group, there was an increased risk of spontaneous abortion with high paternal urinary PCP concentration [odds ratio (OR) = 2.09, 95% Confidence Interval (CI), 1.05–4.14], and maternal exposure to 4-n-OP and alkylphenol(s) also significantly increased the risk of spontaneous abortion (OR = 2.21, 95% CI, 1.02–4.80; OR = 2.81, 95% CI, 1.39–5.65, respectively). Our study firstly provides the evidence that paternal PCP exposure, maternal 4-n-OP and alkylphenol(s) exposure are associated with spontaneous abortion in humans.     

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。     

Structure optimization and annual performance analysis of the lens-walled compound parabolic concentrator

The primary lens-walled compound parabolic concentrator (lens-walled CPC) has a significant advantage of a larger half acceptance angle as a static solar concentrator, but it also has a drawback of a low optical efficiency. In order to overcome this drawback, in this article, series of structure parameters were investigated and compared to further improve the optical efficiency within the half acceptance angle combined with the material properties. The average optical efficiencies of the improved lens-walled CPCs could achieve more than 82% within the half acceptance angle of 35?. Experiments were adopted to verify the credibility and validity of the simulation. Moreover, annual performance of the lens-walled CPCs comparison with that of the mirror CPC for Nottingham was analyzed. Results show that the improved lens-walled CPC has a higher optical performance for actual building application.     

Enhancement of turbulent scalar mixing and its application by a multihole nozzle in selective catalytic reduction of NOx

The mixing characteristics of a passive scalar in the turbulent flow of a selective catalytic reduction process were numerically and experimentally investigated, focusing especially on an injection nozzle with multiple holes for the reducing agent. The multihole injection nozzle studied has six holes that are perpendicular to the ambient flue gas flow and are located near the tip of the nozzle. Large eddy simulation was applied to the turbulent flow and mixing fields to elucidate the mixing mechanism of the proposed nozzle compared with the single-hole nozzle that is commonly used in the conventional selective catalytic reduction process. From the results, there exist broader regions of higher turbulent intensities for the multihole nozzle than for the conventional single-hole nozzle. These regions are well matched with the positions of high vorticity in the near upstream region of the jet flow issuing from the multiple holes of the nozzle. Consequently, the high turbulent intensities and vorticity magnitudes lead to intensified mixing between the flue gas and the reducing agent. Hence, the most suitable molar ratio between NOx and the reducing agent for the catalytic reaction can be easily obtained within a shorter physical mixing length as a result of the enhanced scalar mixing. Finally, the numerical results were applied to a trial design version of a multihole nozzle, and this nozzle was experimentally tested to confirm its mixing performance.     

污染源水质COD在线仪器比对监测

比较了几种现场应用较多的水质COD在线监测分析与实验室分析方法在原理、方法等方面的主要差异,针对比对过程中存在的实际问题,提出了在样品采集、仪器原理选择、仪器定期校正等方面做好水质COD在线监测比对实验工作的建议。     

颗粒物对污染源COD水质在线监测仪比对监测的影响

污水中的颗粒物是COD在线监测仪在比对监测时出现较大误差的原因之一,就颗粒物对COD在线监测仪是否产生影响以及影响效果进行了实验研究。研究结果表明,COD在线监测仪的预处理系统去除颗粒物会带来比对监测的误差,并且随着颗粒物浓度增加,误差增大;预处理系统过滤器尺寸也会对比对监测的误差产生影响,针对同一浓度水样,孔径越大误差越小,针对同一孔径过滤器则水样浓度越高误差越小。     

Seasonal variations of monocarbonyl and dicarbonyl in urban and sub-urban sites of Xi’an,China

Seventeen airborne carbonyls including monocarbonyls and dicarbonyls were determined in urban and sub-urban sites of Xi’an, China in three seasons in 2010. In winter, acetone was the most abundant carbonyl in the urban site due to usage of organic solvents in constructions and laboratories and its slower atmospheric removal mechanisms by photolysis and reaction with hydroxyl radical than those of formaldehyde and acetaldehyde. In the sub-urban site, acetaldehyde was the most abundant carbonyl, followed by formaldehyde and acetone. During summer, however, formaldehyde was the most dominant carbonyl in both sites. The photooxidations of a wide range of volatile organic compounds (VOCs) yielded much more formaldehyde than other carbonyls under high solar radiation and temperature. In the urban site, the average concentrations of dicarbonyls (i.e., glyoxal and methyglyoxal) in spring and summer were higher than that in winter. Transformation of aromatic VOCs emitted from fuel evaporation leads to the formation of 1,2-dicarbonyls. A reverse trend was observed in sub-urban sites, as explained by the relatively low abundances and accumulations of VOC precursors in the rural atmosphere during warm seasons. Moreover, cumulative cancer risk based on measured outdoor carbonyls (formaldehyde and acetaldehyde) in Xi’an Jiaotong University and Heihe was estimated (8.82?×?10^?5 and 4.96?×?10^?5, respectively). This study provides a clear map on the abundances of carbonyls and their source interpretation in the largest and the most economic city in Northwestern China.     

路堑节理边坡开挖稳定性及影响因素分析

以某公路节理岩质边坡为工程背景,首先利用FLAC3D建立该边坡的数值分析模型,计算得到5台阶开挖的安全系数分别为2.62、2.39、1.61、1.06、0.67,并确定其破坏模式为双滑块平面剪切破坏;然后针对边坡的破坏模式建立理论计算模型,分别改变节理的倾角和力学参数(c,),分析它们对稳定性的影响。结果表明:变化下滑块节理面的倾角时,安全系数先变小,而后逐渐增大;变化上滑块节理面的倾角时,安全系数逐渐增大;当c1、c2取值较小时,两者的变化对于安全系数的影响基本相同,但随着取值的增大,c2的影响效果逐渐大于c1。     

煤气生产车间CO气体浓度监控技术的研究

根据某化工厂煤气生产工艺流程,研究预防CO气体泄漏引起的火灾、爆炸和中毒事故的监控系统,分析监控系统的工作原理及电路图,对CO监控技术的研究和气体传感器的研制有重要的参考价值.     

Highly efficient thermo-photocatalytic degradation of tetracycline catalyzed by tungsten disulfide under visible light

Environmental Chemistry Letters - Antibiotics are water and soil contaminants causing the development of multi-resistant bacteria, calling for advanced water treatments. For instance,...