Identification of the anomaly component using BEMD combined with PCA from element concentrations in the Tengchong tin belt,SW China   总被引：1，自引：0，他引：1  

Yongqing Chen  Lina Zhang  Binbin Zhao 《地学前缘(英文版)》2019,10(4):1561-1576

Concentration of elements or element groups in a geological body is the result of multiple stages of rockforming and ore-forming geological processes.An ore-forming element group can be identified by PCA(principal component analysis)and be separated into two components using BEMD(bi-dimensional empirical mode decomposition):(1)a high background component which represents the ore-forming background developed in rocks through various geological processes favorable for mineralization(i.e.magmatism,sedimentation and/or metamorphism);(2)the anomaly component which reflects the oreforming anomaly that is overprinted on the high background component developed during mineralization.Anomaly components are used to identify ore-finding targets more effectively than ore-forming element groups.Three steps of data analytical procedures are described in this paper; firstly,the application of PCA to establish the ore-forming element group;secondly,using BEMD on the o re-forming element group to identify the anomaly components created by different types of mineralization processes; and finally,identifying ore-finding targets based on the anomaly components.This method is applied to the Tengchong tin-polymetallic belt to delineate ore-finding targets,where four targets for Sn(W)and three targets for Pb-Zn-Ag-Fe polymetallic mineralization are identified and defined as new areas for further prospecting.It is shown that BEMD combined with PCA can be applied not only in extracting the anomaly component for delineating the ore-finding target,but also in extracting the residual component for identifying its high background zone favorable for mineralization from its oreforming element group.  相似文献   

Reliability analysis of the induced damage for single-hole rock blasting     

Mahdi Shadab Far  Yuan Wang  Yousif A. H. Dallo 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2019,13(1):82-98

Rock explosion has always been a complex problem because neither rock characteristics nor explosion waves could be accurately estimated. As such, this imposes a high uncertainty on deterministic methodologies available for damage prediction. In this paper, by defining two damage zones around the blast hole, including crushed and cracked zones, a first-order reliability analysis (FORM) was adopted to address this issue. For this purpose, FORM was used in a double-loop algorithm, where the inner loop was responsible for converging the FORM, and the outer loop was assigned to feed the inner loop with new cases. Using such nested-loop algorithm, the probability of exceedance was calculated for any desired damage zone radius. The maximum effect of the involved parameters on the failure probability induced around the blast hole was additionally studied using a parametric reliability analysis. The results showed that the radii for crushed and cracked zones are limited to 0.5 and 4.2?m, respectively, so that the probability of going beyond these limits is less than 1%. Moreover, the analyses of decoupled explosions showed that increasing the gap between the explosion charge and wall of the borehole could severely reduce the failure probability; however, the maximum effect of decoupling ratio occurs in the small range of radii between 0.3?mm and 2.35?m.  相似文献   

长江中游沿岸过江大桥工程建设适宜性评价与地学建议     

赵幸悦子  彭轲  肖攀  何军  程刚  邓必荣 《中国地质调查》2019,6(5):99-106

基于长江中游沿岸地质环境条件及过江大桥场地建设基本要求,优选地形地貌、工程地质条件及区域稳定性3个评价因素,运用层次分析法开展长江中游沿岸过江大桥工程场地建设适宜性评价,将长江中游沿岸过江大桥工程分为适宜开发岸线、较适宜开发岸线、一般适宜开发岸线及非优先开发岸线4个等级。长江中游沿岸地区以较适宜开发岸线和一般适宜开发岸线为主,长度分别为625.19 km和598.99 km,分别占岸线总长度的31.35%和30.04%。针对长江中游不同等级岸线的地质特征,提出了相应的地学建议,为长江中游沿岸过江大桥优化选址提供地学指导,进一步促进长江经济带国土资源空间规划与岸线资源保护利用工作的开展。  相似文献   

Solid phase characterization and metal deportment in a mussel shell bioreactor for the treatment of AMD,Stockton Coal Mine,New Zealand     

《Applied Geochemistry》2016

The Stockton Coal Mine, located on the West Coast of New Zealand, is evaluating the use of a mussel shell bioreactor (MSB) to treat acidic metalliferous runoff from acid forming overburden. This novel approach is similar in concept to vertical flow wetlands (VFWs) and successive alkalinity producing systems (SAPS). The MSB system is a trapezoidal pit 2 m deep, 35 m long, 3–10 m wide with 60° angle sides. During operation it contained 160 tonnes (240 m³) of mussel shell material and was saturated with a 100–200 mm water cap. Influent flowed through the reactor at a mean rate of 0.3 L s⁻¹ resulting in a hydraulic retention time (HRT) of ≈6 days. The prototype MSB was in operation for a total of 1027 days, from June 2009 through March 2012, and effectively sequestered 99.7% of Al, 99.3% of Fe, 98.8% of Ni, 98.4% Tl and 99.3% of Zn, as determined from a previous evaluation of MSB performance. The MSB also effectively neutralized acidity, which resulted in an increase in influent pH from 2.8 to 6.9 in the effluent. Based on an examination of several excavated pits, five distinct reaction zones developed within the MSB. The reaction zones consisted of an allochthonous sediment layer (0–330 mm), an oxidized iron-rich ocherous layer (at 330–350 mm depth), an aluminum layer (at 350–600 mm depth) with geochemical variations throughout (350–500 mm and 500–600 mm); and a chemically reduced bottom shell layer (at 600–1100 mm). Representative samples were collected from each layer and analyzed using a combination of geochemical and physical methods to assess the stability of the secondary minerals and trace metal deportment within the MSB. Major elements Fe, Al, Ni, Tl, and Zn where preferentially associated with particular layers within the MSB. Elevated concentrations of Fe (110,000 mg kg⁻¹) were observed in the allochthonous sediment and ocherous precipitate layers, while Al (27,816 mg kg⁻¹), Ni (55 mg kg⁻¹), and Zn (655 mg kg⁻¹) were elevated within the aluminum and lower reduced depths within the MSB. Trace Tl (21 mg kg⁻¹) showed varying concentrations throughout the MSB, but was strongly correlated to lower layers of the system. Microbial biofilms were observed within the reduced portions of the shell layers often proximal to bacterial shaped sulfides. The geochemical assessment of the MSB presented in this study is the first of its kind for a MSB, and supports the argument that this system is another viable option for passive treatment of AMD.  相似文献   

EM Cygni: A study of its eclipse timings     

Sz. Csizmadia  Zs. Nagy  T. Borkovits  T. Hegedüs  I.B. Bír  Z.T. Kiss 《Astronomische Nachrichten》2008,329(1):39-43

EM Cygni is a Z Cam‐subtype eclipsing dwarf nova. Its orbital period variations were reported in the past but the results were in conflict to each other while other studies allowed the possibility of no period variation. In this study we report accurate new times of minima of this eclipsing binary and update itsO –C diagram.We also estimate the mass transfer rate in EM Cygni system and conclude that the mass transfer is far from the critical value. The mass transfer rate determined from the eclipse timings is in agreement with the spectroscopically determined value. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Molecular lines from protoplanetary nebulae: observations with ALMA     

Valentín Bujarrabal 《Astrophysics and Space Science》2008,313(1-3):209-214

Planetary nebulae (PNe) are formed in a very fast process. In just about 1000 years, the nebula evolves from a spherical and slowly expanding AGB envelope to a PN, with usually axial symmetry and high axial velocities. Molecular lines are known to probe most of the nebular material in young PNe and protoplanetary nebulae (PPNe), and are therefore very useful to study such an impressive evolution. Many quantitative results on these objects have been so obtained, including general structure, total mass and density distribution, kinetic temperatures, velocity fields, etc. Existing observations probe both the gas accelerated by post-AGB shocks and the quiescent components. But the study of crucial regions to understand PN formation (recently shocked shells, regions heated by the stellar UV and inner rotating disks) requires observations at higher frequency and with better spatial resolution.   相似文献   

Investigation on piezoelectric lead zirconate titanate detector bombarded obliquely with hypervelocity iron particles     

S. Takechi  T. Onishi  T. Miyachi  N. Hasebe  K. Nogami  S. Sasaki  T. Iwai  R. Srama 《Planetary and Space Science》2008,56(9):1309-1313

A cosmic dust detector for use onboard a satellite is currently being constructed from piezoelectric lead zirconate titanate (PZT). The characteristics of the PZT detector were studied by bombarding it with hypervelocity iron particles, which were supplied by a Van de Graaff accelerator. There was a linear relationship between the rise time of the signal observed from the detector and the particle's velocity, which was above 10 km/s on impact. It was also found that the rise time was almost independent of the collisional angle between the particles and the PZT surface within the limits of the particle's parameters used in this experiment.  相似文献   

The Norma cluster (ACO 3627) – I. A dynamical analysis of the most massive cluster in the Great Attractor     

P. A. Woudt  R. C. Kraan-Korteweg  J. Lucey  A. P. Fairall  S. A. W. Moore 《Monthly notices of the Royal Astronomical Society》2008,383(2):445-457

A detailed dynamical analysis of the nearby rich Norma cluster (ACO 3627) is presented. From radial velocities of 296 cluster members, we find a mean velocity of 4871 ± 54 km s⁻¹ and a velocity dispersion of 925 km s⁻¹. The mean velocity of the E/S0 population (4979 ± 85 km s⁻¹) is offset with respect to that of the S/Irr population (4812 ± 70 km s⁻¹) by  Δ v = 164 km s⁻¹  in the cluster rest frame. This offset increases towards the core of the cluster. The E/S0 population is free of any detectable substructure and appears relaxed. Its shape is clearly elongated with a position angle that is aligned along the dominant large-scale structures in this region, the so-called Norma wall. The central cD galaxy has a very large peculiar velocity of 561 km s⁻¹ which is most probably related to an ongoing merger at the core of the cluster. The spiral/irregular galaxies reveal a large amount of substructure; two dynamically distinct subgroups within the overall spiral population have been identified, located along the Norma wall elongation. The dynamical mass of the Norma cluster within its Abell radius is  1–1.1 × 10¹⁵  h ⁻¹₇₃ M_⊙  . One of the cluster members, the spiral galaxy WKK 6176 which recently was observed to have a 70 kpc X-ray tail, reveals numerous striking low-brightness filaments pointing away from the cluster centre suggesting strong interaction with the intracluster medium.  相似文献   

The old metal-poor open cluster ESO 92-SC05: accreted from a dwarf galaxy?     

S. Ortolani †  E. Bica  B. Barbuy 《Monthly notices of the Royal Astronomical Society》2008,388(2):723-728

The study of old open clusters outside the solar circle can bring constraints on formation scenarios of the outer disc. In particular, accretion of dwarf galaxies has been proposed as a likely mechanism in the area. We use BVI photometry for determining fundamental parameters of the faint open cluster ESO 92-SC05. Colour–magnitude diagrams are compared with Padova isochrones, in order to derive age, reddening and distance. We derive a reddening   E ( B − V ) = 0.17  , and an old age of ∼6.0 Gyr. It is one of the rare open clusters known to be older than 5 Gyr. A metallicity of   Z ∼ 0.004  or  [M/H]∼−0.7  is found. The rather low metallicity suggests that this cluster might be the result of an accretion episode of a dwarf galaxy.  相似文献   

Gravity and effective temperature distribution on the surface of contact binary systems     

S. Tsantilas  H. Rovithis‐Livaniou 《Astronomische Nachrichten》2008,329(6):596-601

The aim of this work is to study the gravity and the effective temperature distribution on the outer equipotential surface of a contact binary. In particular, the lines of constant g, (the iso‐g curves), are computed and plotted on the outer surface C_s of contact configurations. Since the gravity distribution would also specify the effective temperature distribution on the binary's common photosphere through the gravity darkening effect, these lines correspond to isothermals too. Applications have been made to two contact binaries; namely, to AW UMa and OO Aql, two systems with very different mass ratios. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献