腐殖活性污泥对SBR工艺降解污染物的影响研究

介绍了腐殖活性污泥处理技术在国内外的发展情况,对在SBR工艺及投加腐殖土填料形成腐殖活性污泥的SBR工艺降解污染物效果进行了对比分析,结果表明：投加腐殖土填料对SBR工艺去除COD的效果没有明显影响,但可缩短COD的降解时间;投加腐殖土填料的SBR反应器对N和P去除效果明显优于普通SBR工艺。     

Effect of phosphate rock and triple superphosphate on soil phosphorus fractions and their plant-availability and downward movement in two volcanic ash soils under <Emphasis Type="Italic">Pinus radiata</Emphasis> plantations in New Zealand

Changes in phosphorus (P) fractions and their plant-availability and downward movement in two strongly P fixing acidic Andosols (Allophanic and Pumice Soils) under Pinus radiata plantations in New Zealand were studied 2 years after triple superphosphate (TSP) and a phosphate rock (BGPR, origin Ben Guerir, Morocco) application, each at four rates, to determine the fate and plant availability of fertilizer-derived P in these soils. The rate of increase of the concentrations of the P fractions was highest for NaOH-P_i (inorganic P associated with Fe and Al oxides and allophane) when TSP was applied and highest for H₂SO₄-P_i (predominantly calcium phosphates or apatite-type P minerals) when BGPR was applied. The largest pool of soil P, the NaOH-P_o (labile organic P), was unaffected by the P fertilizer applications. The rate of NaOH-P_i concentration increase was higher in the higher P fixing Allophanic Soil than in the Pumice Soil. Both types of fertilizers increased resin-P_i (Inorganic P freely available to the plant) and Bray-2 P concentrations but only the TSP application increased Olsen P concentration. Phosphorus derived from TSP and BGPR applications moved down to 10–20 cm soil depth within 2 years of application in the Pumice Soil, but did not move below 10 cm depth in the higher P fixing and less porous Allophanic Soil. The fertilizers significantly increased needle P concentrations 2, 3 and 4 years after fertilizer application, but did not have any significant effect on tree growth.     

Long-term impact of chronosequential land use change on soil carbon stocks on a Swedish farm

Agricultural practices and land use significantly influence soil carbon storage. The processes that are affected by land use and management are generally understood, but uncertainties in projections are high. In this paper, we investigate the long-term effects of chronosequential land use change from grassland to cropland and vice versa on soil carbon stock dynamics in four fields on a Swedish farm. Between 1850 and 1920, three of the fields were converted from grassland into cropland, and one was converted back to grassland in 1971. The fourth (control) field is a grassland that has never been ploughed. In 1937, the four fields were sampled at 111 points in a regular grid (25 or 50 m) and the dried soil samples were stored at our Department. In 1971 and 2002, the original grid points were revisited and re-sampled. Land use changes affected the soil C stock significantly. In 1937, carbon stocks were significantly smaller in the arable fields than in the grassland soil. In the field that was converted from arable back to grassland, soil C increased significantly at an average rate of about 0.4 Mg ha⁻¹ year⁻¹. A soil C balance model (ICBM) driven by standard meteorological data and soil carbon input estimated from yield records described soil carbon dynamics reasonably well, although the range of simulated relative changes in C stocks between 1937 and 2002 in the four fields (from −7.4 to +8.8%) was narrower than those measured (from −19.5 to +16.5%). There are only few long-term studies in Northern Europe available for quantifying the effect of land use change on soil carbon stocks and the results presented here are therefore useful for improving predictions of changes in soil carbon driven by land use change.     

Utility detection and positioning on the urban site Sense-City using Ground-Penetrating Radar systems

This paper presents the design of a novel Ground-Penetrating Radar (GPR) test site that has been integrated into the mini-city demonstrator Sense-City located at University Paris-Est (France). This test site provides several sources of measurement interest expressed by the presence of a multilayered soil with significant dielectric contrasts, and various dielectric pipes and blades buried at various depths in trenches filled with a backfill soil different from the natural soil. This paper presents experimental Bscans associated with the pipe zone acquired by three different GPR systems at frequencies ranging from 300 MHz to 1.5 GHz. The interpretation and comparison of the raw Bscans have allowed to characterize the dielectric properties of the soil layers, and to detect the hyperbola signatures of the buried pipes. The results of this study will help to guide future developments on polarization, operating frequency and signal processing to extract parameters (orientation, dielectric characteristics, position and size) associated with pipes.     

A critical analysis of the performance of plate- and point-electrodes for determination of electrical properties of the soil mass

In the recent past, researchers have started utilizing electrical properties of the soil mass for its characterization by employing either plate- or point electrodes. Though, plate-electrodes are easy to use for laboratory experiments, and quantification of geometrical characteristics of the electric field generated within them is easy to quantify, their application for in-situ experiments and for samples of cylindrical shape becomes difficult. On the other hand, usage of point-electrodes which are cylindrical in shape, are used for moisture content determination of the soil or migration of contaminants in it, for coarse-grained soils and fine-grained soils might yield erroneous results, due to the presence of inter particle voids and presence of cavities & anomalies, respectively. Furthermore, quantification of geometrical parameters of the electric field of point-electrodes is quite difficult which results erroneous measurements in determination of electrical properties of the material, in which they are installed. Hence, establishment of the uniqueness of electrical properties obtained from the plate- and point-electrodes, for identical samples becomes utmost important. With this in view, COMSOL Multiphysics® was employed to simulate the electrical response of various geomaterials in their uncontaminated and contaminated states and results were critically evaluated vis-à-vis those obtained from the impedance analysis (1 Hz to 40 MHz). Efforts have also been made to relate the geometrical dimensions of electrodes and electric field generated across the point electrodes, which would facilitate proper design and installation of sensors in a material to achieve the desired output. This study demonstrates the suitability and versatility of the point-electrodes for various (field and laboratory) applications where in moisture profiling and contaminant transport is to be established.     

土洞穴的桩基加固

本文介绍了穿越土洞穴的桩基压桩曲线的变化，桩承载能力的计算方法和桩身稳定性的校核．     

Studies of the rate of migration of radiocesium in some types of soils of Eastern Poland

The activity of Cs-137 and Cs-134 in some types of soils of Eastern Poland was studied. The contribution of Cs-137 from post-Chernobyl fall-out as a function of depth in the soil profiles was calculated from the Cs-134:Cs-137 activity ratio taken from the literature just after the Chernobyl accident. Such information makes it possible to calculate the rate of vertical migration of radiocesium in various types of soils. The rate of the post-Chernobyl Cs-137 migration was found to exceed the rate of migration of Cs-137 from experimental nuclear explosions in the atmosphere. Cs-137 from the Chernobyl accident was found in a layer of soil a few cms thick in most of the soils which were examined. The contribution of post-Chernobyl radiocesium to the total contamination of the surface layer (0–5 cm) with cesium was ≈77%.     

二酮苯装置地下溶剂20#碳钢管线泄漏原因分析

通过对二酮苯装置地下溶剂20#碳钢管线穿孔、泄漏现象进行剖析,结合金相显微分析、腐蚀介质成分分析、现代物理技术分析及其结果,分析了泄漏原因,探讨了腐蚀机理,进而提出相应的防护措施。     

Economics of herbaceous bioenergy crops for electricity generation: Implications for greenhouse gas mitigation

This paper examines the optimal land allocation for two perennial crops, switchgrass and miscanthus that can be co-fired with coal for electricity generation. Detailed spatial data at county level is used to determine the costs of producing and transporting biomass to power plants in Illinois over a 15-year period. A supply curve for bioenergy is generated at various levels of bioenergy subsidies and the implications of production for farm income and greenhouse gas (GHG) emissions are analyzed. GHG emissions are estimated using lifecycle analysis and include the soil carbon sequestered by perennial grasses and the carbon emissions displaced by these grasses due to both conversion of land from row crops and co-firing the grasses with coal. We find that the conversion of less than 2% of the cropland to bioenergy crops could produce 5.5% of the electricity generated by coal-fired power plants in Illinois and reduce carbon emissions by 11% over the 15-year period. However, the cost of energy from biomass in Illinois is more than twice as high as that of coal. Costly government subsidies for bioenergy or mandates in the form of Renewable Portfolio Standards would be needed to induce the production and use of bioenergy for electricity generation. Alternatively, a modest price for GHG emissions under a cap-and-trade policy could make bioenergy competitive with coal without imposing a fiscal burden on the government.     

非饱和土力学理论的研究意义及其工程应用

介绍了目前土力学的最新研究动态，阐述了非饱和土力学的研究历史及研究意义，结合南水北调工程中 膨胀土问题，将非饱和土抗剪强度理论深度地应用于工程实际的试验研究，在室内进行了土的吸力与含水量的关系试验和三轴强度试验，在现场研究了天然膨胀土坡中的吸力分布，比较了各种吸力测量仪器和方法和，这些研究工作为非饱和地理论的工程运用积累了经验。