Correlations of Eisenia fetida metabolic responses to extractable phenanthrene concentrations through time

Eisenia fetida earthworms were exposed to phenanthrene for thirty days to compare hydroxypropyl-β-cyclodextrin (HPCD) extraction of soil and ¹H NMR earthworm metabolomics as indicators of bioavailability. The phenanthrene 28-d LC₅₀ value was 750 mg/kg (632-891, 95% confidence intervals) for the peat soil tested. The initial phenanthrene concentration was 319 mg/kg, which biodegraded to 16 mg/kg within 15 days, at which time HPCD extraction suggested that phenanthrene was no longer bioavailable. Multivariate statistical analysis of ¹H NMR spectra for E. fetida tissue extracts indicated that phenanthrene exposed and control earthworms differed throughout the 30 day experiment despite the low phenanthrene concentrations present after 15 days. This metabolic response was better correlated to total phenanthrene concentrations (Q² = 0.59) than HPCD-extractable phenanthrene concentrations (Q² = 0.46) suggesting that ¹H NMR metabolomics offers considerable promise as a novel, molecular-level method to directly monitor the bioavailability of contaminants to earthworms in the environment.     

用我国各地实测资料拟合的高架源大气扩散参数

采用Ｂｒｉｇｇｓ大气扩散参数的一般式（σ＝ａｘ（１＋βｘ）＾－１／２）将国内一些实测大气扩散参数组织拟合,求出高架源大气扩散参数。拟合大气扩散参数经与ＧＢ３８４０－９１和Ｂｒｉｇｇｓ大气扩散参数比较结果合理,一般适用于１００ｍ 以上的高架源扩散情况。因此在大气扩散计算中有实用价值。     

镧负载沸石壳聚糖复合吸附剂高效除磷性能研究

本研究制备合成一种新型可高效除磷的镧负载复合吸附剂材料(La-MZ/CTS),考察了材料的表面特性以及投加量、初始溶液pH、共存阴离子等因素对除磷效果的影响.SEM、BET和EDS分析说明负载镧后,材料表面均匀覆盖了La(OH)3并且表现出较大的孔径和比表面积,分别为16.681 nm、32.342 m2·g-1材料对...     

趋势面拟合法在煤矿瓦斯地质变量预测中的应用研究

从瓦斯地质学的观点出发,将反映煤层瓦斯基本参数的空间变化规律看做是与其赋存地质条件密切相关的连续函数。结合趋势面拟合及其模型优化的原理和方法分析得出了淮北矿业集团公司芦岭煤矿井田范围内瓦斯含量的变化及分布与其位置坐标的对应数值关系,依据该数值关系可对矿井深部采场和未开采区域实施比较准确、可靠的定量瓦斯预测。该方法也适用于其他具有相似特征的瓦斯地质变量分析。     

自燃煤矸石山内部温度拟合研究

了解煤矸石山内部温度的变化对煤矸石山自燃深度的测算以及煤矸石山自燃的预防具有重要的作用。分析了王庄煤矸石山温度探测试验的数据,采取合适的拟合方法,建立温度拟合模型,揭示出自燃煤矸石山内部温度的变化趋势,进而为下一步的灭火工作做好准备。通过模型的比较、验证,证明研究最后得到的基于一元二次函数和指数函数预测模型是切实可行的。     

垃圾土压缩应变模型研究

研究垃圾土的压缩应变模型参数对填埋场的设计、建设以及管理是至关重要的.本文根据重庆市城市生活垃圾的组成特点,用配制的垃级土进行单级长期加载压缩试验.试验结果表明:试验初期压缩应变量较大,经过一个加速期以后,应变趋于稳定.压缩应变速率在24 h之前变化较大,24 h后趋于平缓,建议用24 h的压缩应变代替极限压缩应变.根...     

Application of cupuassu shell as biosorbent for the removal of textile dyes from aqueous solution

The cupuassu shell (Theobroma grandiflorum) which is a food residue was used in its natural form as biosorbent for the removal of C.I. Reactive Red 194 and C.I. Direct Blue 53 dyes from aqueous solutions. This biosorbent was characterized by infrared spectroscopy, scanning electron microscopy, and nitrogen adsorption/desorption curves. The effects of pH, biosorbent dosage and shaking time on biosorption capacities were studied. In acidic pH region (pH 2.0) the biosorption of the dyes were favorable. The contact time required to obtain the equilibrium was 8 and 18 h at 298 K, for Reactive Red 194 and Direct Blue 53, respectively. The Avrami fractionary-order kinetic model provided the best fit to experimental data compared with pseudo-first-order, pseudo-second-order and chemisorption kinetic adsorption models. The equilibrium data were fitted to Langmuir, Freundlich, Sips and Radke-Prausnitz isotherm models. For both dyes the equilibrium data were best fitted to the Sips isotherm model.     

昆明机场植物多样性及鸟类适宜性评估

鸟撞灾害是威胁航空安全的重要因素之一,其主要原因在于机场生境为鸟类提供了食物、水和庇护场所等多种适宜的生存条件。本文以样方法为主要调查方法,对昆明巫家坝机场的植物群落类型、高度、盖度等进行详细调查,并以植物在群落中的地位、植株高度、为鸟类提供食物的能力等3个方面对植物的鸟类适宜指数进行评估。结果显示机场内现有11种草本植物群落、1种灌木植物群落共12种群落类型;含有植物60种,隶属于20科55属,其中对鸟类有强烈吸引作用的植物有13种。根据机场及其附近区域的生境特点,应严格控制对鸟类有吸引作用种类的种群数量和分布范围,并对此进行了讨论,提出了一系列的鸟类防控综合措施,以达到降低机场对鸟类吸引力的目的。     

火力发电厂NO、SO_2排放量的计算及其在综合模型下的数据拟合

火力发电厂的气体污染物,主要包括NO、SO2等,所以,NO、SO2的含量的确定是决定一个电厂排污等级的重要参数,也是确定火力发电厂排污费用的主要依据。本文结合《全国排污系数普查结果》引入了确定污染物的新方法--排污系数法。通过此方法对火电厂所产生的NO、SO2进行了定量分析,并在此基础上引入了NO、SO2综合条件下的拟合模型,通过具体的算例确定了拟合系数以及拟合曲线,得到了很好的效果。     

Influence of welding speed and power on residual stress during gas tungsten arc welding (GTAW) of thin sections with constant heat input: A study using numerical simulation and experimental validation

The temperature distribution and residual stresses for a GTAW circumferential butt joint of AISI 304 stainless steel using numerical simulation have been evaluated. For evaluation of weld induced residual stresses, the analysis of heat source fitting was carried out with heat inputs ranging from 200 to 500 J/mm to arrive at optimal heat input for obtaining proper weld penetration and heat affected zone (HAZ). For this chosen heat input, the influence of different weld speeds and powers on the temperature distribution and the residual stresses is studied. The heat source analysis revealed the best choice of heat input as 300 J/mm. The residual stresses on the inner and outer surfaces, and along the radial direction were computed. Increase in temperature distribution as well as longitudinal and circumferential residual stresses was observed with the increase in weld speed and power. The validity of the results obtained from numerical simulation is demonstrated with full scale shop floor welding experiments.