At‐a‐station hydraulic geometry relations, 2: calibration and testing

Using a large number of data sets obtained from various sources, the geometric relations derived in Part 1 are calibrated and verified using the split sampling approach. The calibration of parameters shows that the change in stream power is not shared equally among hydraulic variables and that the unevenness depends on the boundary conditions to be satisfied by the channel under consideration. The agreement between the observed values of the hydraulic variables and those predicted by the derived relations is close for the verification data set and lends credence to the hypotheses employed in this study. Copyright © 2007 John Wiley & Sons, Ltd.     

Post‐Synthesis of Ti‐SBA‐15 in Supercritical CO2‐Ethanol Solution

Ti‐SBA‐15 materials with Ti incorporated into the framework of SBA‐15 and controllable Ti contents were successfully prepared via a post‐treatment route in supercritical CO₂‐ethanol solution, followed by calcination. The resultant Ti‐SBA‐15 materials were characterized by means of different techniques including X‐ray diffraction, X‐ray photoelectron spectroscopy, transmission electron microscopy, IR analysis, and N₂ sorption analysis. It was demonstrated that the resultant materials retained a structure similar to that of the parent SBA‐15, and Ti was incorporated into the framework of SBA‐15. At high Ti content, i.e, Si/Ti = 5:1, a TiO₂ phase formed and was coated onto the inner surface of SBA‐15 in addition to the incorporation of the Ti in the framework. The BET surface areas of the Ti‐SBA‐15 samples decreased with increasing Ti content. The presence of small amounts of H₂O in the reaction medium may have resulted in some TiO₂ nanoparticles being uniformly distributed in the pores of the SBA‐15 accompanying the incorporation of Ti in the SBA‐15 framework.     

Urban fluvial flood modelling using a two‐dimensional diffusion‐wave treatment,part 2: development of a sub‐grid‐scale treatment

This paper develops and tests a sub‐grid‐scale wetting and drying correction for use with two‐dimensional diffusion‐wave models of urban flood inundation. The method recognizes explicitly that representations of sub‐grid‐scale topography using roughness parameters will provide an inadequate representation of the effects of structural elements on the floodplain (e.g. buildings, walls), as such elements not only act as momentum sinks, but also have mass blockage effects. The latter may dominate, especially in structurally complex urban areas. The approach developed uses high‐resolution topographic data to develop explicit parameterization of sub‐grid‐scale topographic variability to represent both the volume of a grid cell that can be occupied by the flow and the effect of that variability upon the timing and direction of the lateral fluxes. This approach is found to give significantly better prediction of fluvial flood inundation in urban areas than traditional calibration of sub‐grid‐scale effects using Manning's n. In particular, it simultaneously reduces the need to use exceptionally high values of n to represent the effects of using a coarser mesh process representation and increases the sensitivity of model predictions to variation in n. Copyright © 2005 John Wiley & Sons, Ltd.     

Out‐of‐plane effects in 2D borehole‐to‐surface resistivity tomography and applications in mineral exploration

In this paper, we discuss the effects of anomalous out‐of‐plane bodies in two‐dimensional (2D) borehole‐to‐surface electrical resistivity tomography with numerical resistivity modelling and synthetic inversion tests. The results of the two groups of synthetic resistivity model tests illustrate that anomalous bodies out of the plane of interest have an effect on two‐dimensional inversion and that the degree of influence of out‐of‐plane body on inverted images varies. The different influences are derived from two cases. One case is different resistivity models with the same electrode array, and the other case is the same resistivity model with different electrode arrays. Qualitative interpretation based on the inversion tests shows that we cannot find a reasonable electrode array to determine the best inverse solution and reveal the subsurface resistivity distribution for all types of geoelectrical models. Because of the three‐dimensional effect arising from neighbouring anomalous bodies, the qualitative interpretation of inverted images from the two‐dimensional inversion of electrical resistivity tomography data without prior information can be misleading. Two‐dimensional inversion with drilling data can decrease the three‐dimensional effect. We employed two‐ and three‐dimensional borehole‐to‐surface electrical resistivity tomography methods with a pole–pole array and a bipole–bipole array for mineral exploration at Abag Banner and Hexigten Banner in Inner Mongolia, China. Different inverse schemes were carried out for different cases. The subsurface resistivity distribution obtained from the two‐dimensional inversion of the field electrical resistivity tomography data with sufficient prior information, such as drilling data and other non‐electrical data, can better describe the actual geological situation. When there is not enough prior information to carry out constrained two‐dimensional inversion, the three‐dimensional electrical resistivity tomography survey is the better choice.     

Impact of Ca2+ and Mg2+ on the Removal of F− by Magnesium Potassium Phosphate

This study investigates the influence of Ca²⁺ and Mg²⁺ on the removal of F^? by magnesium potassium phosphate (MPP) from water. The kinetic experiments reveal that the F^? concentration decreased from 3.5 to 3.31 mg L^?1 in a single (F^?) system and to 1.45 mg L^?1 in a ternary system (F^?, Ca²⁺, and Mg²⁺) after 1 min, respectively. Thus, the F^? removal efficiencies are found to increase by about 53% with the co‐active effect of Ca²⁺ and Mg²⁺ in the solution. Moreover, Ca²⁺ and Mg²⁺ are almost completely removed in the F^?, Ca²⁺, and Mg²⁺ system. According to the pseudo‐first‐order modeling, the rate constants k for F^?, Ca²⁺, and Mg²⁺ are 0.00348, 0.0106, and 0.0159 min^?1 respectively; thus, Mg²⁺ > Ca²⁺ > F^?. In the ternary system, the removal efficiencies are 53.29–66.03% for F^?, 99.99–100% for Ca²⁺, and 87.21–95.19% for Mg²⁺ with initial pH 5–10. The removal efficiencies of F^? increases with increases in initial concentrations of F^?, Ca²⁺, and Mg²⁺. The removal of F^? is governed by two routes: 1) adsorption by electrostatic interactions and outer sphere surface complexation; 2) co‐precipitation with Ca₃(PO₄)₂, CaHPO₄, Mg₃(PO₄)₂, and Mg(OH)₂.     

Geochemistry and petrology of garnet‐bearing S‐type Shir‐Kuh Granite,southwest Yazd,Central Iran

The Jurassic Shir‐Kuh granitoid batholith in Central Iran intrudes Lower Jurassic sandstones and shales. The batholith consists of three main facies: (i) a granodioritic facies to the north; (ii) a monzogranitic facies spread throughout the batholith; and (iii) a leucogranitic facies along the northwestern margin. The granodiorites are composed mainly of plagioclase, quartz, K‐feldspar, biotite, and some muscovite, garnet, cordierite, ilmenite, zircon, apatite, and monazite. This facies contains variable amounts of restite minerals which are mainly defined by calcic plagioclase cores and small aggregates of biotite. The monzogranites, with mineral assemblages similar to those in the granodiorites, range from relatively mafic (cordierite‐bearing) to felsic (muscovite‐rich) rocks. The leucogranites, exposed as small stock and dykes, consist mainly of quartz, K‐feldspar, and sodic plagioclase. The batholith is peraluminous, calc‐alkaline, and typical of S‐type, as indicated by Na₂O content (2.74%), molecular Al₂O₃/(CaO + Na₂O + K₂O) (A/CNK) ratio (1.17), K₂O/Na₂O ratio (1.39), and isotopic data ([⁸⁷Sr/⁸⁶Sr]_i = 0.715). The rocks are characterized by enrichment in large ion lithophile elements such as Rb, Th and K and depletion in high field strength elements such as Nb and Ti. Chondrite‐normalized rare earth element (REE) patterns are characterized by light rare earth element (LREE) enrichment, with values of (La/Yb)_N between 4.5 and 19.53, unfractionated heavy rare earth element (HREE) with values of (Gd/Yb)_N between 0.98 and 2.88, and a distinct negative Eu. The parental magma of the Shir‐Kuh Granite was derived from a plagioclase‐rich metasedimentary source (local anatexis of metagreywacke) in the crust, with heat input from mantle melt components. The separation of restite crystals from the primary melt followed by the fractional crystallization appears to have been an effective differentiation process in the batholith.     

High‐accuracy practical spline‐based 3D and 2D integral transformations in potential‐field geophysics

Potential, potential field and potential‐field gradient data are supplemental to each other for resolving sources of interest in both exploration and solid Earth studies. We propose flexible high‐accuracy practical techniques to perform 3D and 2D integral transformations from potential field components to potential and from potential‐field gradient components to potential field components in the space domain using cubic B‐splines. The spline techniques are applicable to either uniform or non‐uniform rectangular grids for the 3D case, and applicable to either regular or irregular grids for the 2D case. The spline‐based indefinite integrations can be computed at any point in the computational domain. In our synthetic 3D gravity and magnetic transformation examples, we show that the spline techniques are substantially more accurate than the Fourier transform techniques, and demonstrate that harmonicity is confirmed substantially better for the spline method than the Fourier transform method and that spline‐based integration and differentiation are invertible. The cost of the increase in accuracy is an increase in computing time. Our real data examples of 3D transformations show that the spline‐based results agree substantially better or better with the observed data than do the Fourier‐based results. The spline techniques would therefore be very useful for data quality control through comparisons of the computed and observed components. If certain desired components of the potential field or gradient data are not measured, they can be obtained using the spline‐based transformations as alternatives to the Fourier transform techniques.     

Hydrologic‐response simulations for the North Fork of Caspar Creek: second‐growth,clear‐cut,new‐growth,and cumulative watershed effect scenarios

This study demonstrates that comprehensive hydrologic‐response simulation can be a useful tool for studying cumulative watershed effects. The simulations reported here were conducted with the Integrated Hydrology Model (InHM). The location of the 473 ha study site is the North Fork of the Caspar Creek Experimental Watershed, near Fort Bragg, California. Existing information from a long‐term monitoring programme and new soil‐hydraulic property measurements made for this study were used to parameterize InHM. Long‐term continuous wet‐season simulations were conducted for the North Fork catchments and main stem for second‐growth, clear‐cut and new‐growth scenarios. The simulation results show that the increases and decreases, respectively, for throughfall and potential evapotranspiration related to clear‐cutting had quantifiable impacts on the simulated hydrologic response at both the catchment and watershed scales. Model performance was best for the new‐growth simulation scenarios. To improve upon the simulations reported here would require additional soil‐hydraulic property information from across the study area. Although principally focused on the integrated hydrologic response, the effort reported here demonstrates the potential for characterizing distributed responses with physics‐based simulation. The search for a comprehensive understanding of hydrologic response will require both data‐intensive discovery and concept‐development simulation, from both integrated and distributed perspectives. Copyright © 2013 John Wiley & Sons, Ltd.     

Topographic locations and size of earthquake‐ and typhoon‐generated landslides,Tachia River,Taiwan

Analysis of mapped landslide locations using a high‐resolution (5‐m grid) digital elevation model (DEM) in the Tachia River basin, Taiwan, finds distinct differences in the topographic locations and size of landslides during the 1999 Chi‐Chi earthquake and the 2001 Toraji typhoon. Our analysis supports Densmore and Hovius' hypothesis that earthquake‐induced landslides cluster near ridgetops due to topographic amplification of ground shaking, and that typhoon‐induced landslides occur with greater frequency lower on slopes. In addition, the differing topographic locations of seismically‐induced and subsequent typhoon‐induced landslides shows no evidence of residual post‐earthquake influences on landslides during typhoon Toraji previously hypothesized for drainage basins closer to the earthquake epicenter. Our results support the interpretation that in this tectonically active landscape, seismically‐induced landslides help shatter and erode ridgetops but typhoon‐triggered landslides concentrate erosion farther downslope, with the combination acting to more uniformly lower upland terrain than either process does individually. Copyright © 2013 John Wiley & Sons, Ltd.     

Seismic performance analysis of BRBs and gussets in a full‐scale 2‐story BRB‐RCF specimen

The implementation of buckling‐restrained braces (BRBs) for new reinforced concrete frame (RCF) constructions is limited. This study investigates the seismic forces and stability in the BRBs and gussets of a 2‐story full‐scale RCF specimen by using Abaqus models and a newly proposed stability evaluation method. The hybrid and cyclic loading test results are accurately predicted by the Abaqus analyses. Existing methods for computing the gusset interface forces for steel buildings from both the brace and the frame actions are compared with the Abaqus results. The applicability of these methods for the BRB‐RCF design is critically evaluated. It is confirmed that the Parallel‐2 method is suitable for estimating the BRB force demand imposed on the corner gusset and the generalized uniform force method is good for the corner gusset at the base. In addition, existing stability evaluation methods for BRBs and gussets are applied to investigate the out‐of‐plane (OOP) buckling of the first‐story BRB observed at the end of tests. The proposed stability model incorporates the BRB restrainer's flexural effects and 4 rotational springs in assessing the BRB's buckling. This model confirms that the BRB and the gusset's OOP buckling limit states could be coupled and must be evaluated together. By incorporating the flexural effects of the steel casing and the infilled grout, the proposed model satisfactorily predicts the OOP buckling of the first‐story BRB and gussets. These research results can be used for the implementation of BRBs in new RC frame constructions.     

Near‐fault ground motions,and the response of elastic and inelastic single‐degree‐of‐freedom (SDOF) systems

In order to investigate the response of structures to near‐fault seismic excitations, the ground motion input should be properly characterized and parameterized in terms of simple, yet accurate and reliable, mathematical models whose input parameters have a clear physical interpretation and scale, to the extent possible, with earthquake magnitude. Such a mathematical model for the representation of the coherent (long‐period) ground motion components has been proposed by the authors in a previous study and is being exploited in this article for the investigation of the elastic and inelastic response of the single‐degree‐of‐freedom (SDOF) system to near‐fault seismic excitations. A parametric analysis of the dynamic response of the SDOF system as a function of the input parameters of the mathematical model is performed to gain insight regarding the near‐fault ground motion characteristics that significantly affect the elastic and inelastic structural performance. A parameter of the mathematical representation of near‐fault motions, referred to as ‘pulse duration’ (T_P), emerges as a key parameter of the problem under investigation. Specifically, T_P is employed to normalize the elastic and inelastic response spectra of actual near‐fault strong ground motion records. Such normalization makes feasible the specification of design spectra and reduction factors appropriate for near‐fault ground motions. The ‘pulse duration’ (T_P) is related to an important parameter of the rupture process referred to as ‘rise time’ (τ) which is controlled by the dimension of the sub‐events that compose the mainshock. Copyright © 2004 John Wiley & Sons, Ltd.     

Green and Eco‐Friendly Removal of Mycotoxins with Organo‐Bentonites; Isothermal,Kinetic, and Thermodynamic Studies

In the current study the application of organo‐modified bentonite for the adsorption of mycotoxins (aflatoxin B1, citrinin, patulin, and zearalenone) is presented. The modification of clays is carried out using benzyl‐tri‐n‐butyl ammonium bromide (BTB), benzethonium chloride (BTC), and dioctyl sodium sulfosuccinate (DSS). Various experimental parameters such as pH, time, adsorbent dose, and mycotoxins concentration are thoroughly studied. The modified clays (B‐BTB, B‐BTC and B‐DSS) are characterized by X‐ray fluorescence, X‐ray diffraction, and Fourier transform infrared spectroscopy. The results depicted the high detoxification efficiency (≈99%) of modified clays for the removal of mycotoxins under optimized conditions (pH 5, time: 30 min, adsorbent amount: 50 mg). The adsorption capacities of modified clays are found in the order of: B‐BTC (AFB1: 18.02, CIT: 18.35, PAT: 18.21, ZEA: 18.09 mg g^?1) > B‐BTB (AFB1: 17.7, CIT: 18.11, PAT: 17.95, ZEA: 17.90 mg g^?1) > B‐DSS (AFB1: 17.5, CIT: 18.02, PAT: 17.86, ZEA: 17.80 mg g^?1). The obtained results fitted well with thermodynamic, isothermal (Langmuir) and pseudo‐second order kinetics. Low cost organo‐modified bentonite shows the promise in mitigating mycotoxin contamination, which could improve food safety and reduce environmental contamination.     

The Kinect: a low‐cost,high‐resolution,short‐range 3D camera

We present a novel application of the Kinect?, an input device designed for the Microsoft® Xbox 360® video game system. The device can be used by Earth scientists as a low‐cost, high‐resolution, short‐range 3D/4D camera imaging system producing data similar to a terrestrial light detection and ranging (LiDAR) sensor. The Kinect contains a structured light emitter, an infrared camera (the combination of these two produce a distance image), a visual wavelength camera, a three‐axis accelerometer, and four microphones. The cost is ~ US $100, frame rate is 30 Hz, spatial and depth resolutions are mm to cm depending on range, and the optimal operating range is 0.5 to ~5 m. The resolution of the distance measurements decreases with distance and is ≤1 mm at 0.5 m and ~75 mm at 5 m. We illustrate data collection and basic data analysis routines in three experiments designed to demonstrate the breadth and utility of this new sensor in domains of glaciology, stream bathymetry, and geomorphology, although the device is applicable to a number of other Earth science fields. Copyright © 2012 John Wiley & Sons, Ltd.     

Geochemical characteristics and Sr‐Nd‐Hf isotope compositions of Late Triassic post‐collisional A‐type granites in Sarudik,SW Sumatra,Indonesia

Late Triassic A‐type granites are identified in this study in Sarudik, SW Sumatra. We present new data on zircon U–Pb geochronology, whole‐rock major and trace elements and Sr‐Nd‐Hf isotope geochemistry, aiming to study their petrogenesis and tectonic implications. LA‐ICP‐MS U–Pb dating of zircon separated from one biotite monzogranite sample yields a concordia age of 222.6 ±1.0 Ma, indicating a Late Triassic magmatic event. The studied granites are classified as weakly peralumious, high‐K calc‐alkaline granites. They exhibit high SiO₂, K₂O + Na₂O, FeO/(FeO + MgO) and Ga/Al ratios and low Al₂O₃, CaO, MgO, P₂O₅ and TiO₂ contents, with enrichment of Rb, Th and U and depletion of Ba, Sr, P and Eu, showing the features of A‐type granites. The granites have zircon ε_Hf(t) values from ?4.6 to ?0.4 and whole‐rock ε_Nd(t) values from ?5.51 to ?4.98, with Mesoproterozoic T_DM2 ages (1278–1544 Ma) for both Hf and Nd isotopes. Geochemical and isotopic data suggest that the source of these A‐type granites is the Mesoproterozoic continental crust, without significant incorporation of mantle‐derived component, and their formation is controlled by subsequent fractional crystallization. The Sarudik A‐type granites are further assigned to A2‐type formed in post‐collisional environment. Combined with previous knowledge on the western SE Asia tectonic evolution, we conclude that the formation of the Late Triassic A‐type granites is related to the post‐collisional extension induced by the crustal thickening, gravitational collapse, and asthenosphere upwelling following the collision between the Sibumasu and the East Malaya Block.     

A comparison of pre‐ and post‐remediation water quality,Mineral Creek,Colorado

Pre‐ and post‐remediation data sets are used herein to assess the effectiveness of remedial measures implemented in the headwaters of the Mineral Creek watershed, where contamination from hard rock mining has led to elevated metal concentrations and acidic pH. Collection of pre‐ and post‐remediation data sets generally followed the synoptic mass balance approach, in which numerous stream and inflow locations are sampled for the constituents of interest and estimates of streamflow are determined by tracer dilution. The comparison of pre‐ and post‐remediation data sets is confounded by hydrologic effects and the effects of temporal variation. Hydrologic effects arise due to the relatively wet conditions that preceded the collection of pre‐remediation data, and the relatively dry conditions associated with the post‐remediation data set. This difference leads to a dilution effect in the upper part of the study reach, where pre‐remediation concentrations were diluted by rainfall, and a source area effect in the lower part of the study reach, where a smaller portion of the watershed may have been contributing constituent mass during the drier post‐remediation period. A second confounding factor, temporal variability, violates the steady‐state assumption that underlies the synoptic mass balance approach, leading to false identification of constituent sources and sinks. Despite these complications, remedial actions completed in the Mineral Creek headwaters appear to have led to improvements in stream water quality, as post‐remediation profiles of instream load are consistently lower than the pre‐remediation profiles over the entire study reach for six of the eight constituents considered (aluminium, arsenic, cadmium, copper, iron, and zinc). Concentrations of aluminium, cadmium, copper, lead, and zinc remain above chronic aquatic‐life standards, however, and additional remedial actions may be needed. Future implementations of the synoptic mass balance approach should be preceded by an assessment of temporal variability, and modifications to the synoptic sampling protocol should be made if necessary. Published in 2009 by John Wiley & Sons, Ltd.