Empirical relationships for estimating stream depletion by a well pumping near a gaining stream   总被引：1，自引：0，他引：1  

Di Matteo L  Dragoni W 《Ground water》2005,43(2):242-249

Siting wells near streams requires an accurate estimate of the quantity of water derived from the river due to pumping. A number of hydrogeological and hydraulic parameters influence this value. This study estimates stream depletion under steady-state conditions for a variety of hydrogeological systems. A finite differences model was used to analyze several hydrogeological situations, and for each of these the stream depletion was estimated using an advective transport method. An empirical equation for stream depletion was obtained for the case of a stream that partially penetrates the aquifer and a pumping well that is screened over a portion of the aquifer. The derived equation, which is valid for both isotropic and anisotropic conditions, expresses stream depletion as a function of the unit inflow to the river, the discharge of the pumping well, the well screen length, the distance between the river and pumping well, the wetted perimeter, and a new parameter called "overlap," which is defined to be the distance between the riverbed and the top of well screen. The overlap parameter makes it possible to consider indirectly the vertical component of flow, which is accentuated when the well is screened below the streambed. The formula proposed here should be useful in deciding where to locate a pumping well and to decide the appropriate length of its screen.  相似文献   

Detecting Randomness in Spatial Point Patterns: A “Stat-Geometrical” Alternative   总被引：1，自引：0，他引：1  

Paulo Sérgio Lucio  Nilson Luiz Castelucio de Brito 《Mathematical Geology》2004,36(1):79-99

There are several methods to test the hypothesis of complete spatial randomness of point patterns. This work involves a new geometrical-based strategy to detect spatial arrangements, which takes into account both Euclidean and angular distances, defining a triangle-based network. An asymptotic test based on the Kolmogorov–Smirnov statistic is proposed to accommodate this situation. To assess the usefulness of this method (Stat-Geo), simulations based on Monte Carlo procedures, conducted using SPLUS, give satisfactory results with a high degree of accuracy. As expected, the new technique proposed in this paper, performs better than traditional ones like distance-based or angle-based, since more information (combining distance and angle) is introduced in the decision-making system. This approach is a very simple way to offer high efficiency results for a low computational cost. Furthermore, this alternative method allows barycentric interpolation of the unsampled points into a two-dimensional simplex (triangular) framework.  相似文献   

Estimation of monthly global solar irradiation using the Hargreaves–Samani model and an artificial neural network for the state of Alagoas in northeastern Brazil     

Gustavo Bastos Lyra  Sidney Sára Zanetti  Anderson Amorim Rocha Santos  José Leonaldo de Souza  Guilherme Bastos Lyra  José Francisco Oliveira-Júnior  Marco Antônio Maringolo Lemes 《Theoretical and Applied Climatology》2016,125(3-4):743-756

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Artisanal ceramic factories using wood combustion:A nanoparticles and human health study     

Kátia Martinello  James C.Hower  Diana Pinto  Carlos E.Schnorr  Guilherme L.Dotto  Marcos Leandro Silva Oliveira  Claudete G.Ramos 《地学前缘(英文版)》2022,(1):488-497

The ceramics industry,resulting from developments of modern compounds,is a segment of great influence in worldwide sustainability.Artisanal ceramic factories based on wood combustion have significant risks for the creation and discharge of atmosphere nanoparticles(NPs)and ultra-fine particles(UFPs).At present,there is insufficient recognition on the influence of engineered-NPs on the atmosphere and health.Real improvements are indispensable to diminish contact with NPs.The present study demonstrates the main NPs and UFPS present in an area of intense artisanal wood-combustion ceramic manufacturing.Particulate matter was sampled for morphological,chemical,and geochemical studies by sophisticated electron microbeam microscopy,X-Ray Diffraction,and Raman spectroscopy.From NPs configuration(<10 nm)we identify nucleation.Several amorphous NPs(>10 nm)were produced around the studied artisanal ceramic factories.This study presents an indication of the recent information on population and work-related contact to NPs in the artisanal ceramic factories and their influence on health.  相似文献   

Phase-equilibrium geobarometers for silicic rocks based on rhyolite-MELTS. Part 1: Principles,procedures, and evaluation of the method     

Guilherme?A.?R.?GualdaEmail author  Mark?S.?Ghiorso 《Contributions to Mineralogy and Petrology》2014,168(1):1033

Constraining the pressure of crystallization of magmas is an important but elusive task. In this work, we present a method to derive crystallization pressures for rocks that preserve glass compositions (either glass inclusions or matrix glass) representative of equilibration between melt, quartz, and 1 or 2 feldspars. The method relies on the well-known shift of the quartz–feldspar saturation surface toward higher normative quartz melt compositions with decreasing pressure. The critical realization for development of the method is the fact that melt, quartz and feldspars need to be in equilibrium at the liquidus for the melt composition. The method thus consists of calculating the saturation surfaces for quartz and feldspars using rhyolite-MELTS over a range of pressures, and searching for the pressure at which the expected assemblage (quartz+1 feldspar or quartz+2 feldspars) is found at the liquidus. We evaluate errors resulting from uncertainties in glass composition using a series of Monte Carlo simulations for a quartz-hosted glass inclusion composition from the Bishop Tuff, which reveal errors on the order of 20–45 MPa for the quartz+2 feldspars constraint and on the order of 25–100 MPa for the quartz+1 feldspar constraint; we suggest actual errors are closer to the lower bounds of these ranges. We investigate the effect of fluid saturation in two ways: (1) By applying our procedure over a range of water contents for three glass compositions; we show that the effect of fluid saturation is more important at higher pressures (~300 MPa) than at lower pressures (~100 MPa), but reasonable pressure estimates can be derived irrespective of fluid saturation for geologically relevant H₂O concentrations >3 wt% and (2) by performing the same type of pressure determinations with a preliminary version of rhyolite-MELTS that includes a H₂O–CO₂ mixed fluid phase; we use a range of H₂O and CO₂ concentrations for two compositions characteristic of early-erupted and late-erupted Bishop Tuff glass inclusions and demonstrate that calculated pressures are largely independent of CO₂ concentration (for CO₂ <1,000 ppm), at least for relatively high H₂O contents, as expected in most natural magmas, such that CO₂ concentration can be effectively neglected for application of our method. Finally, we demonstrate that pressures calculated using the rhyolite-MELTS geobarometer compare well with those resulting from H₂O–CO₂ glass inclusion barometry and Al-in-hornblende barometry for an array of natural systems for which data have been compiled from the literature; the agreement is best for quartz-hosted glass inclusions, while matrix glass yields systematically lower rhyolite-MELTS pressures, suggestive of melt evolution during eruptive decompression.  相似文献   

The role of infiltration processes in steep slope stability of pyroclastic granular soils: laboratory and numerical investigation   总被引：1，自引：0，他引：1  

Emilia Damiano  Lucio Olivares 《Natural Hazards》2010,52(2):329-350

Rainfall-induced landslides on steep slopes are a common feature in much of Italy’s mountain areas covered by shallow-pyroclastic deposits. Generally, these deposits are unsaturated and have a slope angle higher than 40°–50°; hence their stability is due to the positive effect of matric suction on soil shear strength. During rainfall, rainwater infiltration causes a decrease in suction, which in turn causes changes in soil mechanical and hydraulic properties, leading towards an instability process. However, the response of pyroclastic soil slopes to rainwater infiltration is not fully understood. The aim of this study is to link slope instability to the infiltration process on the basis of advanced geotechnical characterization, in situ monitoring and numerical analysis calibrated through a back-analysis of well-instrumented flume tests.  相似文献   

Inhomogeneous gravity     

Timothy Clifton  David F. Mota  John D. Barrow 《Monthly notices of the Royal Astronomical Society》2005,358(2):601-613

We study the inhomogeneous cosmological evolution of the Newtonian gravitational 'constant' G in the framework of scalar–tensor theories. We investigate the differences that arise between the evolution of G in the background universes and in local inhomogeneities that have separated out from the global expansion. Exact inhomogeneous solutions are found which describe the effects of masses embedded in an expanding Friedmann–Robertson–Walker (FRW) Brans–Dicke universe. These are used to discuss possible spatial variations of G in different regions. We develop the technique of matching different scalar–tensor cosmologies of different spatial curvature at a boundary. This provides a model for the linear and non-linear evolution of spherical overdensities and inhomogeneities in G . This allows us to compare the evolution of G and     that occurs inside a collapsing overdense cluster with that in the background universe. We develop a simple virialization criterion and apply the method to a realistic ΛCDM cosmology containing spherical overdensities. Typically, far slower evolution of     will be found in the bound virialized cluster than in the cosmological background. We consider the behaviour that occurs in Brans–Dicke theory and in some other representative scalar–tensor theories.  相似文献   

Gravitational instability in binary protoplanetary discs: new constraints on giant planet formation     

Lucio Mayer  James Wadsley  Thomas Quinn  Joachim Stadel 《Monthly notices of the Royal Astronomical Society》2005,363(2):641-648

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COMPASS: an instrument for measuring the polarization of the CMB on intermediate angular scales     

Philip C. Farese  Giorgio Dall&#x;Oglio  Josh Gundersen  Brian Keating  Slade Klawikowski  Lloyd Knox  Alan Levy  Chris O&#x;Dell  Alan Peel  Lucio Piccirillo  John Ruhl  Peter Timbie 《New Astronomy Reviews》2003,47(11-12):1033

COMPASS is an on-axis 2.6-m telescope coupled to a correlation polarimeter. The entire instrument was built specifically for CMB polarization studies. Careful attention was given to receiver and optics design, stability of the pointing platform, avoidance of systematic offsets, and development of data analysis techniques. Here we describe the experiment, its strengths and weaknesses, and the various things we have learned that may benefit future efforts to measure the polarization of the CMB.  相似文献   

Landslide influence on turbidity and total solids in Cubat?o do Norte River, Santa Catarina, Brazil     

Masato Kobiyama  Aline de Almeida Mota  Fernando Grison  Joana Nery Giglio 《Natural Hazards》2011,59(2):1077-1086

The rainfall events that occurred in the Cubat?o do Norte River watershed, Santa Catarina State, Brazil, in 2008, were characterized by both high intensities and amounts and triggered landslides in this watershed. The objective of the present study was to analyze the influence of landslides on the turbidity and the total solid concentration (TS) in this river using turbidity, TS, and river discharge data obtained from March 23, 2008, to June 11, 2010. The comparison between turbidity and discharge patterns implies that the landslide process was not continuous and increased the turbidity intermittently and irregularly. The sediment yield during the landslide occurrence was approximately five times higher than without the landslide, even though the discharges were similar. The turbidity/discharge relationship during the landslide occurrence was markedly different from that before and after the occurrence. The correlation coefficients between turbidity and TS showed that the landslide significantly changed the sediment yield in this watershed. The result indicates that sediment yield estimations at the watershed level should be treated more carefully when landslides occur.  相似文献