Determining short-term changes in the hydraulic properties of a sandy-loam soil by a three-run infiltration experiment     

V. Bagarello  N. Cecere  S. M. David 《水文科学杂志》2020,65(7):1191-1203

ABSTRACT

Soil structure-dependent parameters can vary rapidly as a consequence of perturbing events such as intense rainfall. Investigating their short-term changes is therefore essential to understand the general behaviour of a porous medium. The aim of this study is to gain insight into the effects of wetting, perturbation and recovery processes through different sequences of Beerkan infiltration experiments performed on a sandy-loam soil. Two different three-run infiltration experiments (LHL and LLL) were carried out by pouring water at low (L, non-perturbing) and high (H, perturbing) heights above the soil surface and at short time intervals (hours, days). The results demonstrate that the proposed method allows one to capture short-term variations in soil structure-dependent parameters. The developed methodology is expected to simplify the parameterization of hydrological models with temporally variable soil hydraulic properties.  相似文献   

A nonlinear elastic solution for 1-D subsidence due to aquifer storage and recovery applications   总被引：2，自引：1，他引：1  

Jiang?LiEmail author 《Hydrogeology Journal》2003,11(6):646-658

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含铜、铋和银的金精矿堆浸工艺综合回收试验研究     

程东会  何江涛  王金祥  李国斌  沈照理 《现代地质》2006,20(2):322-328

采用生物氧化技术和化学方法,利用堆浸工艺分步提取,对含Au 140~150 g/t、Ag 900~1 000 g/t、B i 9.0%~10.0%、Cu14%~17%的多金属浮选金精矿的综合回收工艺进行了研究。经小型搅拌试验,确定了生物氧化浸铜—氰化浸金、NaC l-FeC l3-HC l体系(氯盐法)浸出铋和银的技术方法。通过柱浸试验,研究了利用该方法分步浸取Au、Ag、Cu和B i在堆浸工艺中的可行性。在10 t精矿的扩大试验验中,验证了柱浸试验所取得的工艺指标和参数。试验中掺入骨架材料,解决了精矿在堆浸中的渗透问题;生物氧化过程中,菌种在含高浓度铜离子浸出液中反复驯化,对铜的耐受力提高到30 g/L;在NaC l-FeC l3-HC l体系浸出B i和Ag时,用H2O2将浸出液中的Fe2+氧化成Fe3+,使浸出液能循环使用,且B i和Ag同时浸出。Au、Ag、Cu和B i的最终浸出率分别为92.98%、65.09%、45.33%和53.49%。  相似文献   

Multiple Parameter Regularization: Numerical Solutions and Applications to the Determination of Geopotential from Precise Satellite Orbits   总被引：1，自引：0，他引：1  

Peiliang Xu  Yoichi Fukuda  Yumei Liu 《Journal of Geodesy》2006,80(1):17-27

Kaula’s rule of thumb has been used in producing geopotential models from space geodetic measurements, including the most recent models from satellite gravity missions CHAMP. Although Xu and Rummel (Manuscr Geod 20 8–20, 1994b) suggested an alternative regularization method by introducing a number of regularization parameters, no numerical tests have ever been conducted. We have compared four methods of regularization for the determination of geopotential from precise orbits of COSMIC satellites through simulations, which include Kaula’s rule of thumb, one parameter regularization and its iterative version, and multiple parameter regularization. The simulation results show that the four methods can indeed produce good gravitational models from the precise orbits of centimetre level. The three regularization methods perform much better than Kaula’s rule of thumb by a factor of 6.4 on average beyond spherical harmonic degree 5 and by a factor of 10.2 for the spherical harmonic degrees from 8 to 14 in terms of degree variations of root mean squared errors. The maximum componentwise improvement in the root mean squared error can be up to a factor of 60. The simplest version of regularization by multiplying a positive scalar with a unit matrix is sufficient to better determine the geopotential model. Although multiple parameter regularization is theoretically attractive and can indeed eliminate unnecessary regularization for some of the harmonic coefficients, we found that it only improved its one parameter version marginally in this COSMIC example in terms of the mean squared error.  相似文献   

EGM96/2008重力场模型在似大地水准面构建中的应用     

王鸣鹤  孙成志  许丹萍  吴晓倩 《北京测绘》2020,(5):687-690

似大地水准面的构建可以将GPS测量的高程迅速转化为正常高,极大降低高程测量的成本,提高相关工作效率。将EGM96/2008重力场模型与“移去-恢复”法相结合,在矿区内建立似大地水准面,并使用不同的插值方法,验证最优方案。结果表明,使用二次线性插值的EGM2008重力场模型拟合效果更好,模型外符合精度达到3.6 mm,更适合应用于该区域似大地水准面构建。  相似文献   

南京九华山铜矿伴生金的赋存状态及分布规律     

黄松  陈德松 《矿产与地质》1998,12(2):101-105

九华山铜矿床中伴生金已具综合利用价值。金以矿物态为主,金矿物主要为银金矿、含银自然金。金矿物粒度较细,大于２００目者占２４．３４％,金矿物主要嵌布于黄铜矿粒间或裂隙中。金的理想回收率为６６．３０％,空间分布上,沿矿体走向金西低东高,倾向金北高南低,深度金随深度增加而增加。  相似文献   

Further discussion on the intercomparison of the trace metal concentrations and particle size of fluvial sediment recovered from two centrifuge systems     

S. Santiago  R. L. Thomas  J.-L. Loizeau  P.-Y. Favarger  J.-P. Vernet 《水文研究》1990,4(3):283-287

A single large volume water sample taken at the mouth of the Upper Rhone River on Lake Geneva was processed directly in parallel through two continuous flow centrifuges, a Westphalia and an Alfa-Laval. Sediment was recovered from the Westphalia, and separately from the bowl and brass core of the Alfa-Laval. The three sediment samples were analyzed for particle size and the following elements: Zn, Cu, Mn, Cr, P, Co, B, V, Be, Sr, Na, Pb, Ni, Ba, Fe, Ca, and Mg. Results indicate that the particle size recovery of both machines is similar when sediment from the brass core and bowl of the Alfa-Laval are combined, and that the recovery for all elements other than Cu, V, B, and Pb are the same when the particle size differences are taken into account. Sediment from the Alfa-Laval brass core is clearly contaminated by Cu, B and is also elevated in V and Pb but not to a significant extent. The sediment recovered from the bowl of the Alfa-Laval is contaminated only with Cu, with a 10 ppm increase over the 52 ppm recovered in the Westphalia sediment. Operating procedures involve the discarding of the brass core sediment and the mixing of the Alfa-Laval bowl sediment with that from the Westphalia. The consequent increase in Cu is estimated at less than 5 ppm or within the confidence level of the analysis. These procedures are recommended to all operators of non modified Alfa-Laval units.  相似文献   

Results based management in fisheries: Delegating responsibility to resource users     

《Marine Policy》2015

While the notion of results based management has been devoted recent attention in the context of reforming European fisheries management, it remains unclear what it entails. A conceptual model of results based management in fisheries is proposed as a way for public authorities to delegate specific management and documentation responsibilities to resource users. The model comprises three defining features: (1) That authorities define measurable objectives for the utilization of fisheries resources; (2) that resource users are made responsible for achieving these objectives and for (3) providing documentation that allows for an audit of the extent to which they are met. Selected cases are used to illustrate these features. Rationales and prospects of introducing results based management as an alternative in a European fisheries management context are discussed, giving consideration to how it may be pursued under the reformed common fisheries policy.  相似文献   

Responses of benthic macroinvertebrates to thin-layer disposal of dredged material in Mississippi Sound, USA     

Wilber DH  Clarke DG  Rees SI 《Marine pollution bulletin》2007,54(1):42-52

Benthic community responses to thin-layer disposal of dredged material were assessed at three sites in Mississippi Sound, USA. Community composition differed between disposal and reference sites (ANOSIM) for each disposal event. Oweniid sand worms, Amphinomid fire worms, and brittle stars (Ophiuriodea) contributed the most to community distinctions between disposal and reference sites (SIMPER), with higher abundances at the disposal sites. Total infaunal abundance was similar to pre-disposal and reference conditions within 3-10 months of thin-layer disposal. Distinctions in community composition between disposal and reference sites (nMDS) persisted throughout the 16-month study period, but were less pronounced at the site where sediment composition was unchanged by disposal. Size distributions of some taxa (e.g., gastropod and hemichordate) suggest adults recolonized the newly deposited sediments either through vertical migration or lateral immigration from adjacent areas. Thin-layer disposal offers a viable alternative to conventional open-water disposal practices and warrants further exploration for other areas with deeper bathymetries and different hydrodynamic regimes.  相似文献   

高镁磷尾矿的矿石结构与矿物组成     

黄芳  刘世荣  王华  李军旗  陈义 《矿物学报》2010,30(1)

利用电子探针背散射电子成像分析和微区成分分析功能,对贵州瓮福高镁磷尾矿的矿石结构和矿物组成进行了研究,以探索尾矿与其原矿之间的差异,为综合开发利用磷尾矿提供必要的依据。结果表明该高磷尾矿的矿石结构可分为单矿物结构和多矿物碎屑结构两类。前者矿物组成包括白云石单矿物、磷灰石单矿物、褐铁矿单矿物、石英单矿物;后者包括白云石-磷灰石多矿物、磷灰石-白云石-石英多矿物,属高镁低品位磷矿。矿物组成类型按其含量从高到低依次为白云石质尾矿、白云石磷灰石质尾矿、磷灰石白云石石英质尾矿、石英质尾矿、磷灰石质尾矿、褐铁矿质尾矿,白云石质尾矿是尾矿中最丰富的矿物,白云石颗粒是含量最高的碎屑类型。  相似文献