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141.
Application of a Bayesian model to infer the contribution of coalbed natural gas produced water to the Powder River,Wyoming and Montana 下载免费PDF全文
The Powder River Basin (PRB) of Wyoming and Montana contains significant coal and coal bed natural gas (CBNG) resources. CBNG extraction requires the production of large volumes of water, much of which is discharged into existing drainages. Compared to surface waters, the CBNG produced water is high in sodium relative to calcium and magnesium, elevating the sodium adsorption ratio (SAR). To mitigate the possible impact this produced water may have on the quality of surface water used for irrigation, the State of Montana passed water anti‐degradation legislation, which could affect CBNG production in Wyoming. In this study, we sought to determine the proportion of CBNG produced water discharged to tributaries that reaches the Powder River by implementing a four end‐member mixing model within a Bayesian statistical framework. The model accounts for the 87Sr/86Sr, δ13CDIC, [Sr] and [DIC] of CBNG produced water and surface water interacting with the three primary lithologies exposed in the PRB. The model estimates the relative contribution of the end members to the river water, while incorporating uncertainty associated with measurement and process error. Model results confirm that both of the tributaries associated with high CBNG activity are mostly composed of CBNG produced water (70–100%). The model indicates that up to 50% of the Powder River is composed of CBNG produced water downstream from the CBNG tributaries, decreasing with distance by dilution from non‐CBNG impacted tributaries from the point sources to ~10–20% at the Montana border. This amount of CBNG produced water does not significantly affect the SAR or electrical conductivity of the Powder River in Montana. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
142.
Emissions of N2O, CH4, and CO2 from soils at two sites in the tropical savanna of central Venezuela were determined during the dry season in February 1987. Measured arithmetic mean fluxes of N2O, CH4, and CO2 from undisturbed soil plots to the atmosphere were 2.5×109, 4.3×1010, and 3.0×1013 molecules cm-2 s-1, respectively. These fluxes were not significantly affected by burning the grass layer. Emissions of N2O increased fourfold after simulated rainfall, suggesting that production of N2O in savanna soils during the rainy season may be an important source for atmospheric N2O. The CH4 flux measurements indicate that these savanna soils were not a sink, but a small source, for atmospheric methane. Fluxes of CO2 from savanna soils increased ninefold two hours after simulated rainfall, and remained three times higher than normal after 16 hours. More research is needed to clarify the significance of savannas in the global cycles of N2O, CH4, CO2, and other trace gases, especially during the rainy season. 相似文献
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144.
Precipitation samples were collected by filtrating bulk sampler in Kitakyushu City, Japan, from January 1988 to December 1990. Volume weighted annual mean of pH was 4.93, but the pH distribution indicated that most probable value lay in the range pH 6.0–6.4. Volume weighted annual mean concentrations of major ionic components were as follows; SO
4
2–
: 84.2, NO
3
–
: 28.1, Cl–: 86.3, NH
4
+
: 45.5, Ca2+: 63.3, Mg2+: 27.0, K+: 3.4, Na+: 69.0 µ eq l–1. The highest concentrations of these ionic components were observed in winter and the lowest occurred in the rainy season. The ratio of ex-SO
4
2–
/NO
3
–
exhibited the lowest ratio in summer, and the highest ratio in winter. Good correlations were obtained between Cl– and Na+, ex-SO
4
2+
and ex-Ca2+, NO
3
–
and ex-Ca2+, and NH
4
+
and ex-SO
4
2–
, respectively. However, no correlation between Cl– and Na+ with Ca2+ was observed. The relationship of H+ with (ex-SO
4
2–
+ NO
3
–
) - (ex-Ca2+ + NH
4
+
) indicated positive correlation. 相似文献
145.
146.
矿山地理信息系统中的空间和时间四维数据模型 总被引:8,自引:2,他引:8
现有的许多地理信息系统(GISs)一般都没有考虑时间这一维数据。本文依据矿山的特点和需求,提出了能满足空间和时间要求的GIS的概念。针对传统数据模型所存在的缺点,以及根据处理历史数据所具有的特点,提出了一种用于矿业开发的空间和时间综合四维数据模型。这种模型通过采用四维空间线性编码技术,可大大减少数据存贮所需的辅助操作。为了适应综合四维数据处理的需要,笔者研究出了一种新的拓扑结构——四维空间和时间因素的拓扑关系。 相似文献
147.
A series of novel long-chain 3,4-dialkylthiophenes (C36–C54) was identified in a number of sediments ranging from Pleistocene to Cretaceous. The identifications were based on mass spectral characterisation, desulphurisation and mass spectral data of synthesised model compounds. These organic sulphur compounds are probably formed by sulphur incorporation into mid-chain dimethylalkadienes with two methylenic double bonds. These putative precursor lipids are unprecedented and may be considered rather unusual. The distribution of 3,4-dialkylthiophenes in sediments varies considerably with the depositional palaeoenvironment, indicating that these compounds have a potential as molecular markers reflecting changes in palaeoenvironment. 相似文献
148.
本文采用数理统计方法,详细分析了HP—3808A激光测距仪近几年来积累的测量数据,求得仪器平均测距相对精度为1:70万。并且讨论了进一步提高测距精度的技术措施。 相似文献
149.
150.
This paper deals with the influence of different humic substances (HS) on the enzyme activity (EA) of the proteolytic enzyme pronase E. The EA was determined by analyzing the concentration of the amino acid valine hydrolyzed from caseine. For amino acid analysis, a flourescence detector was used after precolumn derivatization and HPLC-separation of the hydrolysis products. The data show that the presence of HS has no adverse effects on amino acid analysis. Based on this result, a decrease of EA was observed in the presence of HS acting as enzyme inhibitors. Clear inhibition effects could be seen for different fulvic acids (HO3 FA, FBR FA and FBR 1.0 FA) at concentrations of 150 mg/L. In case of FBI-2 FA, higher concentrations were necessary to decrease the EA significantly. At an inhibitor concentration of 1500 mg/L the EA was mostly found to be less than 50%. The standard deviations of the results don't allow a differentiation between the HS of different origin and treatment. Specifying HS according to their influence on EA has to remain uncertain. As shown in a kinetic study of the hydrolysis of L-Leucine-2-naphthylamide-hydrochloride, the inhibitor HO3 FA decreases the maximum velocity of the reaction but has no effect on the Michaelis constant. These results indicate that this HS acts as a noncompetitive inhibitor. 相似文献