Improving groundwater-flow modeling using optimal zoning methods

Hydraulic conductivity sometimes exhibits complicated spatial variation over a site. A thorough understanding of the spatial distributions of hydraulic conductivity helps to make deterministic models of groundwater more accurate. This study presents a novel procedure that combines simulated annealing algorithms (SA) and the shortest distance method (SD) with the modular three-dimensional groundwater flow model (MODFLOW). The procedure is applied to a hypothetical site with groundwater-monitoring wells to minimize the difference between simulated and observed hydraulic head for optimal zoning of the spatial distribution of hydraulic conductivity. The results of this optimal zoning method indicate that this new procedure not only improves the efficiency of optimization, but also increases the probability of finding the global optimum, minimizing the errors of the hydraulic head simulated by MODFLOW in two scenarios, one with known and the other with unknown hydraulic conductivity. The results also illustrated that the procedure can effectively determine and delineate hydrogeological zones.     

Oxyphlogopite K(Mg,Ti,Fe)3[(Si,Al)4O10](O,F)2: A new mineral species of the mica group

Oxyphlogopite is a new mica-group mineral with the idealized formula K(Mg,Ti,Fe)₃[(Si,Al)₄O₁₀](O,F)₂. The holotype material came from a basalt quarry at Mount Rothenberg near Mendig at the Eifel volcanic complex in Rhineland-Palatinate, Germany. The mineral occurs as crystals up to 4 × 4 × 0.2 mm in size encrusting cavity walls in alkali basalt. The associated minerals are nepheline, plagioclase, sanidine, augite, diopside, and magnetite. Its color is dark brown, its streak is brown, and its luster is vitreous. D _meas = 3.06(1) g/cm³ (flotation in heavy liquids), and D _calc = 3.086 g/cm³. The IR spectrun does not contain bands of OH groups. Oxyphlogopite is biaxial (negative); α = 1.625(3), β = 1.668(1), and γ = 1.669(1); and 2V _meas = 16(2)° and 2V _calc = 17°. The dispersion is strong; r < ν. The pleochroism is medium; X > Y > Z (brown to dark brown). The chemical composition is as follows (electron microprobe, mean of 5 point analyses, wt %; the ranges are given in parentheses; the H₂O was determined using the Alimarin method; the Fe²⁺/Fe³⁺ was determined with X-ray emission spectroscopy): Na₂O 0.99 (0.89–1.12), K₂O 7.52 (7.44–7.58), MgO 14.65 (14.48–14.80), CaO 0.27 ((0.17–0.51), FeO 4.73, Fe₂O₃ 7.25 (the range of the total iron in the form of FeO is 11.09–11.38), Al₂O₃ 14.32 (14.06–14.64), Cr₂O₃ 0.60 (0.45–0.69), SiO₂ 34.41 (34.03–34.66), TiO₂ 12.93 (12.69–13.13), F 3.06 (2.59–3.44), H₂O 0.14; O=F₂ −1.29; 99/58 in total. The empirical formula is (K_0.72Na_0.14Ca_0.02)(Mg_1.64Ti_0.73Fe_0.30²⁺ Fe_0.27³⁺Cr_0.04)_Σ2.98(Si_2.59Al_1.27Fe_0.14³⁺ O₁₀) O_1.20F_0.73(OH)_0.07. The crystal structure was refined on a single crystal. Oxyphlogopite is monoclinic with space group C2/m; the unit-cell parameters are as follows: a = 5.3165(1), b = 9.2000(2), c = 10.0602(2) ?, β = 100.354(2)°. The presence of Ti results in the strong distortion of octahedron M(2). The strongest lines of the X-ray powder diffraction pattern [d, ? (I, %) [hkl]] are as follows: 9.91(32) [001], 4.53(11) 110], 3.300(100) [003], 3.090(12) [112], 1.895(21) [005], 1.659(12) [−135], 1.527(16) [−206, 060]. The type specimens of oxyphlogopite are deposited at the Fersman Mineralogical Museum in Moscow, Russia; the registration numbers are 3884/2 (holotype) and 3884/1 (cotype).     

用数学形态学变换实现空间分析中的数据处理

论述了数学形态学的基本算法, 并将这一方法引入空间分析的数据处理中。研究表明,该方法具有一定的可行性, 对于空间分析中一些问题的深入研究具有参考价值     

Crystal nucleation and growth produced by continuous decompression of Pinatubo magma

High-temperature decompression experiments demonstrate that crystal textures preserve a record of the style and rate of magmatic ascent. To reinforce this link, we performed a suite of isothermal decompression experiments using starting material from the climactic 1991 Pinatubo eruption. We decompressed experiments from 220 MPa to final, quench pressures of 75 or 30 MPa using continuous decompression rates of 100, 30, 10, 3, 1, and 0.3 MPa h^?1. Amphibole, clinopyroxene, and plagioclase crystallized during the experiments, with plagioclase microlites dominating the assemblage. Total microlite number densities range from 10^7.6±0.4 up to 10^8.2±0.2 cm^?3, with plagioclase accounting for up to 65% of the total number. Plagioclase microlite area increased systematically from 19?±?8 to 937?±?487 µm² with increasing experiment duration. Our textures provide time-integrated records of crystal kinetics. Average nucleation and areal growth rates of plagioclase are highest in the fastest decompressions (~?10^7.5 cm^?3 h^?1 and 10.1?±?4.1 µm² h^?1, respectively) and more than an order of magnitude lower in the slowest experiments (~?10^5.5 cm^?3 h^?1 and 0.8?±?0.2 µm² h^?1, respectively). Both nucleation and growth rates are highest at high degrees of disequilibrium. We find that peak supersaturation-dependent instantaneous rates are generally more than an order of magnitude faster than average rates. We use those instantaneous nucleation and growth rates to introduce an iterative model to evaluate the effects of different decompression rates, decompression paths (continuous, single-step or multistep), and the presence of phenocrysts on final crystallinity and microlite size distribution.     

有限元方法在地震孕育过程与前兆机理研究中的应用进展

有限元方法的基本思想是将连续的求解区域离散为一组有限个、 且按一定方式相互联结在一起的单元的组合体。 有限元方法是目前应用最为广泛的数值模拟方法, 由于能够将复杂介质的力学本构关系及边界条件问题转化成为常规问题的计算程序, 所以越来越多的地震学者将其应用于地震成因与前兆机理研究中。 该文着重介绍了有限元数值分析方法及其模拟在地震孕育过程与前兆机理研究中的应用进展, 并提出开展小尺度规模如岩石中矿物颗粒之间的力学行为的有限元模拟研究等几点建议。     

地震动态应力触发研究进展

本文从以下几方面阐述了近几年来地震动态应力触发的研究进展:地震动态应力触发问题的提出;地震动态应力触发存在的证据(包括地震频度图中探寻被触发震群和独立地震、数字滤波后新发现的被触发地震和形变仪器记录的同震变化和应力阶跃等);地震动态触发的研究现状和机理等.还提出了目前动态应力触发研究中存在的问题,并对其近期的发展进行了展望.     

刍议国际地震保险投保率

地震灾难带来的损失日益增加的问题，让保险业至今难以应对。地震发生频率低、损失巨大而保险公司的承保能力又十分有限，加之，社会公众的投保意识薄弱，造成地震保险投保率过低。从地震灾情入手，介绍了国际地震保险开展情况，剖析了地震保险投保率过低的原因，并针对问题提出了解决措施。     

铅在灰钙土土壤—植物系统与环境中的迁移和环境容量

本文通过作物盆栽试验、区域调查、农田径流和淋溶试验以及土壤生化活性和微生物试验,研究了铅在土壤、植物、水体中的迁移和累积,并通过迁移模式的计算得出了铅的土壤临界浓度和环境容量。     

A Comment on “How Well Can We Measure the Vertical Wind Speed? Implications for Fluxes of Energy and Mass” by Kochendorfer et al.

Kochendorfer et al. (Boundary-Layer Meterol, 145:383–398, 2012) conducted an experiment to evaluate azimuth and angle-of-attack dependent errors of sonic anemometer measurements. Several questions are raised regarding the experimental design and the presented results. The finding that instruments with non-orthogonal sonic paths underestimate fluctuations of vertical wind speed and consequently also scalar fluxes by about 10 % is compared with the results of a hitherto unpublished side-by-side field comparison and other past intercomparison experiments. Scale considerations are presented that raise considerable doubts on the validity of the implicit assumption of Kochendorfer et al. (2012) that the turbulent wind vector is highly correlated across a distance of 1.2 m at a height of 2.5 m over flat grassland, which corresponds to the separation between the sonic anemometers tested in their experiment. Nevertheless, new developments in sonic anemometer design to minimize transducer-shadow effects are desirable.     

Relationships between surface-active organic substances, chlorophyll a and nutrients in the northern Adriatic Sea

Surface-active organic substances (SAS), nutrients, chlorophyll a (Chl a), dissolved oxygen (O₂), salinity (S) and temperature (T) were measured approximately monthly in the northern Adriatic Sea (NA) during two years. Results were elaborated for two stations of different trophic status. Exhaustive statistical examinations of measured variables were performed to contribute to better understanding of the processes and interdependence of the measured parameters. The results of those analyses allowed the region to be described based on several groups of data relevant for particular processes. Chl a appear to be independent parameter; orthosilicate, nitrite and ammonium represent the parameter group most relevant for regeneration processes; the second group includes nutrients dominant in freshwater inputs (orthophosphate and nitrate), while in the third group are parameters related to primary production processes (T, O₂, organic phosphorus and SAS). Probably due to time lags between nutrient uptake and phytoplankton growth as well as between cells growth/division and SAS release, both, the correlation between nutrients and Chl a and the correlation between Chl a and SAS were not statistically significant. Although significantly higher nutrient and Chl a concentrations were found in the mesotrophic western part of the region in comparison to the oligotrophic eastern part, the SAS concentration differences were less marked. It is assumed that more OM is produced, but also at the same time remineralized, at the mesotrophic western part, leading to higher concentrations of regenerated nutrients there. Presence of different phytoplankton taxa and/or fractions (micro and nano) at the two stations may have also contributed to minimize the difference in SAS contents. Higher SAS acidities were noticed in the mesotrophic than in the oligotrophic part.