Dissolution,transport, and fate of lead on a shooting range in the Jefferson National Forest near Blacksburg,VA, USA     

Caleb D. Scheetz  J. Donald Rimstidt 《Environmental Geology》2009,58(3):655-665

Samples taken from a shooting range near Blacksburg, VA, USA provide information about the reservoirs and pathways of lead at shooting ranges in an upland setting and humid environment. The metallic lead shot corrodes rapidly and develops a coating of hydrocerussite (Pb₃(CO₃)₂(OH)₂). Hydrocerussite dissolution releases soluble lead at concentrations ranging from 2 ppb to 2 ppm depending the soil pH values at this site. This soluble lead is captured by the Fe and Mn oxides and carbonates soil fractions. The highest concentration of extractable lead contained in the soil was directly correlated with the highest concentration of lead shot and bullets measured on the shotgun range surface. Eh-pH and hydrolysis diagrams provide a useful geochemical framework for understanding the corrosion process, recognizing the corrosion product(s), understanding their solubility, and identifying the geochemical barriers to lead migration that provides a basis for selecting best management practices for this and other shooting range.  相似文献   

海水ORP对3C钢腐蚀行为的影响     

丁慧 《海洋科学》2013,37(6):73-76

研究了氧化还原电位(Oxidation Reduction Potential, ORP)对海水中碳钢腐蚀电化学特征的影响,应用动电位极化曲线法探讨了 ORP 与碳钢腐蚀行为之间的关系。结果表明,海水的 ORP 参数对碳钢腐蚀行为具有较大的影响,其中 O2/OH?电对的作用占主导,其他电对如 Fe3+/Fe2+也有一定的影响。随着海水 ORP 的增大,其氧化能力越强,碳钢腐蚀电流增大,腐蚀速度加快。水质相对稳定的开放性大洋海水中,可以考虑海水氧化还原电位在碳钢腐蚀速度预测评估中的应用。  相似文献   

海洋环境友好型阻锈剂的筛选和快速评价     

杨圣和  田惠文  侯保荣  李伟华 《海洋科学》2012,36(8):1-8

以量子化学构效关系计算为指导,合成与筛选了两种环境友好型有机阻锈剂化合物,分别是烟酸和烯效唑,通过研究几何最优化构型、总电荷密度分布和分子前线轨道能量分布,发现两种化合物均具有类平面分子结构,能以0°二面角的取向吸附在金属表面;阻锈效率随分子供电子能力增强而提高,能够形成亲核吸附中心的价电子云分布主要集中在N、O、Cl杂原子和共轭双键的周围;并均具有较高的HOMO能量和较小的HOMO-LUMO能量差.使用恒电量法对两种化合物的阻锈效率进行了快速评价,通过采用量子化学复合参数来替代描述分子热力学性质的吸附平衡常数K,将所测阻锈效率与浓度进行函数关联,建立了不受理想吸附假定条件限制的多元非线性构效关系方程.  相似文献   

Mg₂B₂O₅晶须增强AZ91D镁基复合材料在Cl_-溶液中腐蚀行为_*          下载免费PDF全文

王晓民  喇培清  程楚  张廷安 《盐湖研究》2017,25(3):61-66

用电化学方法测量了Mg_2B_2O_5晶须增强AZ91D镁基复合材料在3.5%NaCl溶液中的开路电位、动电位极化曲线和交流阻抗,研究了晶须体积分数对镁合金基体耐腐蚀性能的影响,并利用SEM和XRD表征了腐蚀后复合材料表面的微观形貌和相组成。结果表明,随着Mg_2B_2O_5晶须体积分数的增加,AZ91D镁基复合材料的耐腐蚀性逐渐提高。当硼酸镁晶须的体积分数为35%时,材料的自腐蚀电位提高0.2V以上,自腐蚀流密度降低了1个数量级;SEM测试表明,复合材料表面生成了一层晶须增韧的腐蚀钝化膜,对基体起到保护作用。  相似文献   

山门银矿区水文地质工程地质特征     

李龙江  徐占军 《吉林地质》1992,11(1):106-114

通过地下水的形成、赋存、运移规律以及对富水性、水化学特征的分析研究;通过对区域构造特点、岩组划分、岩体结构、结构面分级、岩石质量等级和其它工程地质条件的分析研究,系统地总结和描述了山门银矿区的水文地质、工程地质特征。  相似文献   

Factors affecting corrosion and approaches for improving durability of ocean reinforced concrete structures   总被引：1，自引：0，他引：1  

Yu-Pu Song  Li-Yuan Song  Guo-Fan Zhao 《Ocean Engineering》2004,31(5-6):779-789

Investigation shows that concrete corrosion is a common problem for ocean reinforced concrete (R.C.) structures along China’s coast. A discussion of the corrosion characteristics, based on real project cases and field surveys, is presented in this paper. These factors that might affect corrosion, such as environmental effects, construction quality, cover thickness, property of the concrete material and structure type, are evaluated. Based on the analysis of these corrosion characteristics and affecting factors, the approaches available to improve the durability of ocean R.C. structures are proposed.  相似文献   

Induction of auroral zone electric currents within the Alaska pipeline     

Wallace H. Campbell 《Pure and Applied Geophysics》1978,116(6):1143-1173

The Alaskar pipeline is a highly conducting anomaly extending 800 miles (1300 km) from about 62° to 69° geomagnetic latitude beneath the most active regions of the ionospheric electrojet current. The spectral behavior of the magnetic field from this current was analyzed using data from standard geomagnetic observatories to establish the predictable patterns of temporal and spatial changes for field pulsation periods between 5 min and 4 hr. Such behavior is presented in a series of tables, graphs and formulae. Using 2- and 3-layer models of the conducting earth, the induced electric fields associated with the geomagnetic changes were established. From the direct relationship of the current to the geomagnetic field variation patterns one can infer counterpart temporal and spatial characteristics of the pipeline current. The relationship of the field amplitudes to geomagnetic activity indices,A _p, and the established occurrence of various levels ofA _p over several solar cycles were employed to show that about half of the time the induced currents in the pipe would be under 1 A for the maximum response oscillatory periods near 1 hr. Such currents should be of minimal consequence in corrosion effects for even a section of the pipeline unprotected by sacrificial electrodes. Of greater interest was the result that the extreme surges of current should reach over one-hundred amperes in the pipeline during high activity.  相似文献   

Effects of soil resistivity on currents induced on pipelines     

Ana Osella  Alicia Favetto 《Journal of Applied Geophysics》2000,44(4):45

The goal of cathodic protection is to prevent corrosion by maintaining buried pipelines at a constant potential with respect to the surrounding soil. In practice, however, the implementation is very complicated since many factors can contribute to the current flowing off the pipe. Design requires characterization of the parameters impacting the corrosion process, such as soil resistivity, size of the pipe and quality of the coating.In the present paper, we have studied the effect of geomagnetic fields on the pipe-induced currents considering it as an additional cause of corrosion. A theoretical method implemented to model the induced currents was tested in a previous work and the effect during disturbed days was quantified. This theoretical model indicated that the intensity of the current induced in a pipeline by the varying geomagnetic field depends on the intensity and rate of change of the field and the electrical resistivity of the soil. This induced current is in equilibrium with the host current and there is no current drainage between the pipeline and the host until, along the length of the pipeline, the host resistivity becomes different. At that point, current must flow between the pipe and host in order to establish a new equilibrium. It is this drainage current, flowing between the pipeline and the host, which causes corrosion problems.Following these results, experimental tests were performed in Tierra del Fuego. In this zone, a geophysical study was made to determine the discontinuities in soil resistivities and simultaneous measurements of the geomagnetic field and the drainage of current were recorded at different sites. The results obtained from the correlation of the data are consistent with the theoretical predictions.  相似文献   

观音岩水电站坝址区右岸岩体溶蚀发育机理研究   总被引：1，自引：0，他引：1  

王锦国  周志芳  陈松峰 《工程地质学报》2011,19(3):409-416

观音岩水电站位于金沙江上游,坝型初拟混凝土重力坝和心墙堆石坝组合坝.坝址区分布有侏罗系中蛇店组(J2s)地层,岩性主要为钙质铁质胶结的砾岩、石英砂岩,其中砾石成分以泥晶灰岩和生物灰岩为主.在地下水作用下砾岩钙质溶蚀形成规模较大的囊状空腔或孔洞,砂岩则表现为钙质胶结物流失溶蚀呈砂土状或砂糖状,对坝基稳定性造成了一定的影响...  相似文献   

Roaldite in the iron-meteorite São Julião de Moreira     

《Chemie der Erde / Geochemistry》2019,79(4):125538

Roaldite – Fe₄N – has been identified in the São Julião de Moreira iron meteorite using electron backscatter diffraction (EBSD) and simultaneously acquired energy-dispersive x-ray spectroscopy (EDS). Mean-periodic-number images derived from raw EBSD patterns confirm this phase by an even higher spatial resolution compared to EDS.Roaldite appears in the form of systematically and repetitively aligned plates. Despite the locally heavy plastic deformation, it is shown that the origin of the oriented precipitation of roaldite is linked to the orientation of the kamacite matrix. Roaldite can be considered to be precipitated from kamacite using an inverse Kurdjumov-Sachs (K-S) or Nishiyama-Wassermann (N-W) orientation relationship. A more accurate discrimination is impossible due to the accumulated shock deformation, which blurs the local reference orientation of kamacite. The habit plane of roaldite is found to be {112}_R, which is most likely parallel to {120}_K of kamacite. Some of the roaldite plates contain two orientation variants which repeatedly alternate. Their misorientation angle is about 12°.  相似文献