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滑坡预报的几个基本问题 总被引:19,自引:0,他引:19
在滑坡预报研究中,必须首先解决与预报密切相关的一些基本问题。否则,往往导致预报误差很大或者预报失败。根据作者的初步探索,本文重点讨论了滑坡预报的分类及定义、预报参数及其监测点的选取、变形突变现象的分析与处理以及斜坡变形阶段的定量判断等基本问题。 相似文献
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Forty-three untreated and actively and passively (wetland) treated coal mine drainage sediments and five yellow-red pigments
were characterized using X-ray fluorescence, fusion-inductively coupled plasma atomic emission spectroscopy, X-ray diffraction,
and tristimulus colorimeter. Primary crystalline iron-bearing phases were goethite and lepidocrocite, and iron phases converted
to hematite upon heating. Quartz was nearly ubiquitous except for synthetic pigments. Gypsum, bassinite, calcite, and ettringite
were found in active treatment sediments. Iron concentrations from highest to lowest were synthetic pigment>wetland sediment>natural
pigment>active treatment (untreated sediments varied more widely), and manganese was highest in actively treated sediments.
Loss on ignition was highest for passively treated sediments. No clear trends were observed between quantified color parameters
(L*, a*, b*, and Redness Index) and chemical compositions. Because sediments from passive treatment are similar in chemistry, mineralogy,
and color to natural pigments, the mine drainage sediments may be an untapped resource for pigment.
Received: 29 December 1997 · Accepted: 11 May 1998 相似文献
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In order to examine the Corg flow in rapid sand filter columns for the elimination of iron and manganese, reduced groundwater was treated in a pilot plant consisting of a trickling filter column (TF I) followed by a wet type filter column (WF II) and a separate wet type filter column (WF sep). Additionally the effect of filtration on BOM was studied by measuring AOC and BDOC. The biological processes in TF I and WF sep led to an elimination of iron, ammonia, and manganese. Moreover, the filtration decreased the NOM content. 21% and 23% of the TOC were eliminated in TF I and in WF sep, respectively. WF II caused no significant Corg reduction. The calculation of the Corg flow in the filter columns showed that bacteria took part in the TOC elimination. From the TOC removed, about 24% was eliminated by metabolic activities of the bacterial population whereas 86% was adsorbed onto iron sludge. Similar results were obtained for the TF I column and for the WF sep column as well. The calculated Corg flow was confirmed by the BDOC measurements. The filtration process led to a BDOC decrease. TF I and WF sep reduced appoximately 35% of the biodegradable organic carbon. In contrast there was no significant elimination by WF II. The AOC results suggest that an AOC production and an AOC elimination process exist in rapid sand filters for groundwater treatment. In the trickling filter column significant AOC production was found, whereas in the wet type filter columns AOC elimination was predominating. 相似文献
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Results from kinetic laboratory studies of reactions of the carbonate radical anion (CO3–·) with aromatic compounds in aqueous solution at T = 298 K are presented. Data were obtained in using a laser photolysis laser long-path absorption (LP-LPLA) apparatus which was designed for direct time-resolved studies of radical reactions. For the reactions of CO3–· with hydroquinone dimethyl ether (2), methyl anisole (3), benzene (4), p-xylene (5), toluene (6), chlorobenzene (7), nitrobenzene (8), and benzonitrile (9), rate coefficients of k2 = (3.0 ± 0.6)·107 M–1 s–1, k3 = (9.7 ± 1.7)·105 M–1 s–1, k4 = (3.2 ± 0.7)·105 M–1 s–1, k5 = (3.8 ± 0.9)·104 M–1 s–1, k6 = (6.8 ± 2.3)·104 M–1 s–1, k7 = (2.7 ± 0.6)·105 M–1 s–1, k8 = (1.4 ± 0.5)·104 M–1 s–1, and k9 < 1.3·102 M–1 s–1 were obtained. In further studies the effect of temperature on the reactions (2), (4), and (5) has been studied. The kinetic data obtained for the reaction of the carbonate radical anion with aromatic compounds were compared to the corresponding reactions of the hydroxyl radical. Finally, these kinetic data were used within a simple model system to investigate the implications of carbonate radical anion kinetics within water treatment processes. It is shown that the degradation of organic pollutants in ·OH-radical based water treatment may proceed via the CO3–·/HCO3· radical under certain conditions. 相似文献
46.
《Marine Policy》2017
Human-mediated transfer and invasions of organisms have permanently altered distribution patterns on a global scale. In response to growing numbers and impacts of invasions, global-scale vector management is advancing to curtail unintentional and unwanted species re-distributions. In marine systems, ocean-going ships have been the major dispersal mechanism across biogeographic barriers, and maritime vector management has become a priority global initiative, including national regulations and recent ratification of an international convention to manage ballast water. This paper provides the first analysis of the pioneering patterns of ballast water treatment systems (BWTS) on board commercial ships, using vessel arrivals to the United States as a model system. Over an opening 28-month period, >200 unique vessels arriving to the U.S. reported BWTS operations, using 58 different systems to treat 4.42 million m3 of discharged ballast water. Although this volume represents <2% of all ballast water discharged in the U.S. per month during this period, there was substantial growth in treated ballast discharge throughout this time. Through 2015, ‘Filtration+UV’ systems were the most common BWTS type installed across all ship types. Currently, BWTSs occur on higher numbers of tankers and bulkers, but a higher proportion of passenger vessels, than other ship types. If BWTSs meet the required discharge standards as intended, this will cause a steep reduction in total discharge of organisms ≥50 µm compared to current practices. While several hurdles in fleet-wide BWTS adoption remain, including the timeline for BWTS installation across the global fleet, we are at a significant milestone in the history and evolution of global shipping, which is undergoing wholesale transition to a new and more effective global-scale ballast vector management strategy. 相似文献
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Jürgen Dartmann Thore Alex Thorsten Dorsch Esther Schevalje Klaus Johannsen 《洁净——土壤、空气、水》2004,32(1):25-32
The effect of softening/decarbonisation and dosage of orthophosphate on copper corrosion was studied in pipe rigs according to the German standard DIN 50931, part 1. A literature study with regard to the effects of phosphate dosing on copper corrosion has shown that on the one hand and in most of the cases a dosage of phosphate led to lower copper concentrations. On the other hand phosphate aggravated the copper corrosion in some cases. The mechanisms are not yet clear and the influence of phosphate on the corrosion of copper remains a question to be answered. Using standardised on‐site corrosion tests (DIN 50931‐1) with virgin copper pipes softening/decarbonisation has decreased the copper concentration. Two effects of phosphate on copper corrosion were noticed: Phosphate dosing decreased the copper oxidation and resulted in lower copper concentration in water. Likewise phosphate hindered the precipitation of cupric ions, which prolonged the existence of copper in water and resulted in a higher copper concentration. As a consequence, dosing phosphate can decrease or increase the copper corrosion, this depends on which effect is dominating. 相似文献