Estimation of transit trip production using Factorial Kriging with External Drift: an aggregated data case study     

Anabele Lindner  Cira Souza Pitombo  Samille Santos Rocha  José Alberto Quintanilha 《地球空间信息科学学报》2016,19(4):245-254

Studies in transportation planning routinely use data in which location attributes are an important source of information. Thus, using spatial attributes in urban travel forecasting models seems reasonable. The main objective of this paper is to estimate transit trip production using Factorial Kriging with External Drift (FKED) through an aggregated data case study of Traffic Analysis Zones in São Paulo city, Brazil. The method consists of a sequential application of Principal Components Analysis (PCA) and Kriging with External Drift (KED). The traditional Linear Regression (LR) model was adopted with the aim of validating the proposed method. The results show that PCA summarizes and combines 23 socioeconomic variables using 4 components. The first component is introduced in KED, as secondary information, to estimate transit trip production by public transport in geographic coordinates where there is no prior knowledge of the values. Cross-validation for the FKED model presented high values of the correlation coefficient between estimated and observed values. Moreover, low error values were observed. The accuracy of the LR model was similar to FKED. However, the proposed method is able to map the transit trip production in several geographical coordinates of non-sampled values.  相似文献   

Metallic Mineral Resources in the Twenty-First Century. I. Historical Extraction Trends and Expected Demand     

Alberto E. Patiño Douce 《Natural Resources Research》2016,25(1):71-90

Industrial, technological, and economic developments depend on the availability of metallic raw materials. As a greater fraction of the Earth’s population has become part of developed economies and as developed societies have become more affluent, the demand on metallic mineral resources has increased. Yet metallic minerals are non-renewable natural resources, the supply of which, even if unknown and potentially large, is finite. An analysis of historical extraction trends for eighteen metals, going back to the year 1900, demonstrates that demand of metallic raw materials has increased as a result of both increase in world population and increase in per-capita consumption. These eighteen metals can be arranged into four distinct groups, for each of which it is possible to identify a consistent pattern of per-capita demand as a function of time. These patterns can, in turn, be explained in terms of the industrial and technological applications, and in some cases conventional uses as well, of the metals in each group. Under the assumption that these patterns will continue into the future, and that world population will grow by no more than about 50% by the year 2100, one can estimate the amount of metallic raw materials that will be required to sustain the world’s economy throughout the twenty-first century. From the present until the year 2100, the world can be expected to require about one order of magnitude more metal than the total amount of metal that fueled technological and economic growth between the age of steam and the present day. For most of the metals considered here, this corresponds to 5–10 times the amount of metal contained in proven ore reserves. The two chief driving factors of this expected demand are growth in per-capita consumption and present-day absolute population numbers. World population is already so large that additional population growth makes only a small contribution to the expected future demand of metallic raw materials. It is not known whether or not the amount of metal required to sustain the world’s economy throughout this century exists in exploitable mineral resources. In the accompanying paper, I show that it is nevertheless possible to make statistical inferences about the size distribution of the mineral deposits that will need to be discovered and developed in order to satisfy the expected demand. Those results neither prove nor disprove that the needed resources exist but can be used to improve our understanding of the challenges facing future supply of metallic raw materials.  相似文献   

DNA and fluorescein tracer tests to study the recharge,groundwater flowpath and hydraulic contact of aquifers in the Umbria-Marche limestone ridge (central Apennines,Italy)     

Lucia Aquilanti  Francesca Clementi  Torquato Nanni  Stefano Palpacelli  Alberto Tazioli  Paola Maria Vivalda 《Environmental Earth Sciences》2016,75(7):626

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Snowmelt contribution to the sustainability of the irrigated Mendoza’s Oasis,Argentina: an isotope study     

Hector Massone  Daniel Martinez  Alberto Vich  Mauricio Quiroz Londoño  Darío Trombotto  Sebastián Grondona 《Environmental Earth Sciences》2016,75(6):520

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Joint editorial – Fostering innovation and improving impact assessment for journal publications in hydrology     

Demetris Koutsoyiannis  Günter Blöschl  András Bárdossy  Christophe Cudennec  Denis Hughes  Alberto Montanari 《水文科学杂志》2013,58(7):1170-1173

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A thermo-plastic constitutive law for brittle-plastic behavior of rocks at high temperatures     

Tomasz Hueckel  Alberto Peano  Rita Pellegrini 《Pure and Applied Geophysics》1994,143(1-3):483-510

Mechanical properties of rocks change under the influence of, temperature. Stress at the onset of yielding, ultimate strength, dilatancy, strain hardening and softening, and the confining pressure at brittle-ductile transition are all reduced by the increasing temperature. This study presents a framework of constitutive modeling of thermo-brittle-plastic behavior of rocks which encompasses these changes. The constitutive law is based on a thermo-plasticity theory first proposed for metals byPrager (1958). Two phenomenological mechanisms have been identified as central for the modeling: temperature dependence of the yield locus (thermal softening), and temperature dependence of the strain-hardening function (thermally enhanced ductility). Material parameters for two rocks, Carrara marble and Westerly granite, were determined on the basis of additional hypotheses. These parameters are used in numerical simulations of triaxial tests at different temperatures. The obtained stress-strain curves compare well to the experimental results. The changes with temperature in the stress at the onset of yielding are more accurately reproduced that the evolution of hardening or softening. Suggestions for possible improvements and future research directions are indicated.  相似文献   

Post glacial lacustrine event sedimentation in an ancient mountain setting: Carboniferous Lake Malanzán (Western Argentina)     

Luis Alberto Buatois  Maria Gabriela Mángano 《Journal of Paleolimnology》1995,14(1):1-22

Lacustrine deposits of the Malanzán Formation record sedimentation in a small and narrow mountain paleovalley. Lake Malanzán was one of several water bodies formed in the Paganzo Basin during the Late Carboniferous deglaciation. Five sedimentary facies have been recognized. Facies A (Dropstones-bearing laminated mudstones) records deposition from suspension fall-out and probably underflow currents coupled with ice-rafting processes in a basin lake setting. Facies B (Ripple cross-laminated sandstones and siltstones) was deposited from low density turbidity currents in a lobe fringe environment. Facies C (Massive or graded sandstones) is thought to represent sedimentation from high and low density turbidity currents in sand lobes. Facies D (Folded sandstones and siltstones) was formed from slumping in proximal lobe environments. Facies E (Wave-rippled sandstones) records wave reworking of sands supplied by turbidity currents above wave base level.The Lake Malanzán succession is formed by stacked turbidite sand lobe deposits. These lobes were probably formed in proximal lacustrine settings, most likely relatively high gradient slopes. Paleocurrents indicate a dominant direction from cratonic areas to the WSW. Although the overall sequence shows a regressive trend from basin fine-grained deposits to deltaic and braided fluvial facies, individual lobe packages lack of definite vertical trends in bed thickness and grain size. This fact suggests aggradation from multiple-point sources, rather than progradation from single-point sources. Sedimentologic and paleoecologic evidence indicate high depositional rate and sediment supply. Deposition within the lake was largely dominated by event sedimentation. Low diversity trace fossil assemblages of opportunistic invertebrates indicate recolonization of event beds under stressed conditions.Three stages of lake evolutionary history have been distinguished. The vertical replacement of braided fluvial deposits by basinal facies indicates high subsidence and a lacustrine transgressive episode. This flooding event was probably linked to a notable base level rise during postglacial times. The second evolutionary stage was typified by the formation of sand turbidite lobes from downslope mass-movements. Lake history culminates with the progradation of deltaic and braided fluvial systems  相似文献   

Emission of nitric oxide from soils and termite nests in a Trachypogon savanna of the Orinoco basin   总被引：2，自引：0，他引：2  

Alberto Rondón  Christer Johansson  Fugenio Sanhueza 《Journal of Atmospheric Chemistry》1993,17(3):293-306

Nitric oxide fluxes from soils in the Trachypogon savanna of the Orinoco basin were determined during the dry season using the static chamber method. The emission from dry soils fluctuated from 0.4 to 3 ng N m^–2 s^–1 and increased up to 25 ng N m^–2 s^–1 after moderate watering or light rain-falls (1 to 5 mm). The mean emission values are up to 6 times lower than one observed earlier at the Chaguaramas site, but up to 10 times higher than one recorded at the Guri site, indicating an important spatial variability in NO fluxes of the Venezuelan savanna region. The changes observed after the addition of nitrogen to the soil, in the form of ammonium and/or nitrate, indicate a high denitrification potential in this acidic soil. Burning of the surface vegetation produced an increase by a factor of 10 in the emission rate of NO, but the effect was relatively short in time, about 5 days. It was estimated for the savanna region that burning increases the total NO soil emission during the dry season by 15% compared to the unburnt case. Soils with termite nests emit 10 times more NO than soil without nests, but the contribution from this source is less than 2% of the total savanna soil flux.  相似文献   

Taphonomy of guanaco bones in Tierra del Fuego     

Luis Alberto Borrero 《Quaternary Research》1990,34(3)

Guanaco carcasses are deposited in great quantities in Cabo San Pablo, Tierra del Fuego (Argentina), as a result of winter stress. Taphonomic studies indicate that the gnawing action of foxes on guanaco (Lama guanicoe) carcasses produces only very tenuous marks on the bones. Lack of sustained interest in the carcasses by carnivores results in slow disarticulation. The articulated and disarticulated bones are exposed to heavy trampling by guanacos, a process that produces vertical migration of small/dense bones and fracturing of the most weathered bones. An understanding of this ongoing process is important for local archaeology, since modern bones are migrating into archaeological contexts. A regional approach to taphonomy is the most appropriate instrument to solve this and other related problems.  相似文献   

Soil-structure interaction with Rayleigh waves     

Alberto Gmez-Mass  John Lysmer  Jian-Chu Chen  H. Bolton Seed 《地震工程与结构动力学》1983,11(4):567-583

Presented is a plane-strain method for soil-structure interaction analysis consisting of the superposition of the free field motions and the interaction motions in a generalized seismic environment. The free field is modelled as a horizontally layered viscoelastic medium and the seismic environment may consist of a combination of S, P and Rayleigh waves. The soil-structure system is modelled with viscoelastic finite elements, transmitting boundaries, viscous boundaries and a three-dimensional simulation. Comparative analyses of the same structure are conducted for an input of R waves and for vertically propagating S and P waves in a rock site and sand site. In the rock site the R waves produce higher peak horizontal spectral acceleration up to 25 per cent, and a significant rocking effect at points away from the centre of gravity of the structure. However, the S and P waves show higher peak vertical spectral acceleration by up to 15 per cent at the centre of the structure. Very similar horizontal response, but higher vertical response only at the centre of the structure for S and P waves, is obtained for the sand site.  相似文献