Multi‐temporal transport network models for accessibility studies     

Diego Bogado Tomasiello  Mariana Giannotti  Renato Arbex  Clodoveu Davis 《Transactions in GIS》2019,23(2):203-223

Vehicle tracking is a spatio‐temporal source of high‐granularity travel time information that can be used for transportation planning. However, it is still a challenge to combine data from heterogeneous sources into a dynamic transport network, while allowing for network modifications over time. This article uses conceptual modeling to develop multi‐temporal transport networks in geographic information systems (GIS) for accessibility studies. The proposed multi‐temporal network enables accessibility studies with different temporal granularities and from any location inside the city, resulting in a flexible tool for transport and urban planning. The implemented network is tested in two case studies that focus on socially excluded people in a large global city, São Paulo, Brazil, including accessibility analyses from slum areas. It explores variations within a day and differences between transport modes across time. Case study results indicate how the accessibility is heterogeneous in low‐income regions.  相似文献   

Groundwater chemical characterization of a Rio de Janeiro coastal aquifer,SE – Brazil     

Emmanoel V. Silva-Filho  Renato G. Sobral Barcellos  Christophe Emblanch  Bernard Blavoux  Silvia Maria Sella  Michel Daniel  Roland Simler  Julio Cesar Wasserman 《Journal of South American Earth Sciences》2009,27(1):100-108

  相似文献   

Ages (U–Pb SHRIMP and LA ICPMS) and stratigraphic evolution of the Neoproterozoic volcano-sedimentary successions from the extensional Camaquã Basin,Southern Brazil     

Liliane Janikian  Renato Paes de Almeida  Antonio Romalino Santos Fragoso-Cesar  Veridiana Teixeira de Souza Martins  Elton Luiz Dantas  Eric Tohver  Ian McReath  Manoel Souza D'Agrella-Filho 《Gondwana Research》2012,21(2-3):466-482

During the Ediacaran, southern Brazil was the site of multiple episodes of volcanism and sedimentation, which are best preserved in the 3000 km² Camaquã Basin. The interlayered sedimentary and volcanic rocks record tectonic events and paleoenvironmental changes in a more than 10 km-thick succession. In this contribution, we report new U–Pb and Sm–Nd geochronological constraints for the 605 to 580 Ma Bom Jardim Group, the 570 Ma Acampamento Velho Formation, and a newly-recognized 544 Ma volcanism. Depositional patterns of these units reveal the transition from a restricted, fault-bounded basin into a wide, shallow basin. The expansion of the basin and diminished subsidence rates are demonstrated by increasing areal distribution and compressed isopachs and increasing onlap of sediments onto the basement to the west. The Sm–Nd isotopic composition of the volcanic rocks indicates mixed sources, including crustal rocks from the adjacent basement. Both Neoproterozoic and Paleoproterozoic sources are indicated for the western part of the basin, whereas only the older Paleoproterozoic signature can be discerned in the eastern part of the basin.  相似文献   

Impact area determination of pyroclastic deposits in Lascar volcano, eruptive process in the year 1993     

Luis Fernández  Gabriel Álvarez  Renato Salinas 《Natural Hazards》2012,60(2):747-760

By means of multi-temporal analysis of satellite images and statistical algorithms, the amount of pyroclastic material deposited on Lascar volcano walls after the gravitational collapse of the eruptive column caused by the eruption that occurred on April the 19th and the 20th in 1993 was determined and quantified. For this analysis, scenes corresponding to Landsat 4 TM in 1989 and Landsat 7 ETM+ in 2001 were used. By careful selection methods such as combination of bands, unsupervised classification, and the Karhunen–Loève transform, detailed analysis of zones of change that correspond to pyroclastic deposits were made. This analysis was complemented with in situ data in order to correct and calibrate the satellite images to identify zones of 1993s eruption pyroclastic deposits. Using Kittler’s and other thresholding algorithms, a search was performed for a proper threshold to binarize the images to determine the surface area covered by the eruptive process. Matlab™ software was used both for general programming and for digital image processing.  相似文献   

Origin and orbital distribution of the trans-Neptunian scattered disc     

A. Morbidelli  V. V. Emel'yanenko  H. F. Levison 《Monthly notices of the Royal Astronomical Society》2004,355(3):935-940

  相似文献   

RR Lyrae pulsational temperature scales: on the consistency between different empirical relations     

Renato De Santis 《Monthly notices of the Royal Astronomical Society》2001,326(1):397-402

In this paper, by assuming the equilibrium temperatures of RRab Lyrae variables defined by Carney, Storm & Jones as correct we show that temperatures derived from ( B − V ) colour (mean colour over the pulsational cycle calculated on the magnitude scale) transformations by Bessel, Castelli & Plez are consistent with the Carney et al. equilibrium temperatures within a probable error of δ  log  T _e =±0.003 . As a consequence, it is shown that the pulsational temperature scale temperature–period–blue amplitude [ T _eff= f ( P , A _B )] relation provided by De Santis, who studied the ( B − V ) colour of about 70 stars of Lub's sample, is a suitable relation, being reddening- and metallicity-free, to calculate equilibrium temperatures for RRab variables. This relation is independent of variable mass and luminosity within a large range of period-shift from the mean period–amplitude relation valid for Lub's sample of variables. On the contrary, it is also shown that a temperature–amplitude–metallicity relation is strictly dependent on the period–amplitude relation of the sample used for calibrating it: we prove that this means it is dependent on both the mass and luminosity variations of variables.  相似文献   

The Kuiper Belt and its Primordial Sculpting     

Morbidelli  A.  Brown  M.E.  Levison  H.F. 《Earth, Moon, and Planets》2003,92(1-4):1-27

We discuss the structure of the Kuiper belt as it can be inferred from the first decade of observations. In particular, we focus on its most intriguing properties – the mass deficit, inclination distribution, the apparent existence of an outer edge and of a correlation among inclinations, colours and sizes – which clearly show that the belt has lost its pristine structureof a dynamically cold proto-planetary disk. Understanding how the Kuiperbelt acquired its present structure will provide insight into the formationof the outer planetary system and on its early evolution. We outline ascenario of primordial sculpting – issued from a combination of mechanismsproposed by various authors – that seems to explain most of the observedproperties of the Kuiper belt. Several aspects are not yet totallyclear. But, for the first time, we have a view – if not of the detailedsculpture – at least of its rough cast.  相似文献   

Direct air capture of CO2 with chemicals: optimization of a two-loop hydroxide carbonate system using a countercurrent air-liquid contactor     

Marco Mazzotti  Renato Baciocchi  Michael J. Desmond  Robert H. Socolow 《Climatic change》2013,118(1):119-135

Direct Air Capture (DAC) of CO₂ with chemicals, recently assessed in a dedicated study by the American Physical Society (APS), is further investigated with the aim of optimizing the design of the front-end section of its benchmark two-loop hydroxide-carbonate system. Two new correlations are developed that relate mass transfer and pressure drop to the air and liquid flow velocities in the countercurrent packed absorption column. These relationships enable an optimization to be performed over the parameters of the air contactor, specifically the velocities of air and liquid sorbent and the fraction of CO₂ captured. Three structured Sulzer packings are considered: Mellapak-250Y, Mellapak-500Y, and Mellapak-CC. These differ in cost and pressure drop per unit length; Mellapak-CC is new and specifically designed for CO₂ capture. Scaling laws are developed to estimate the costs of the alternative DAC systems relative to the APS benchmark, for plants capturing 1 Mt of CO₂ per year from ambient air at 500 ppm CO₂ concentration. The optimized avoided cost hardly differs across the three packing materials, ranging from $518/tCO₂ for M-CC to $568/tCO₂ for M-250Y. The $610/tCO₂ avoided cost for the APS-DAC design used M-250 Y but was not optimized; thus, optimization with the same packing lowered the avoided cost of the APS system by 7 % and improved packing lowered the avoided cost by a further 9 % The overall optimization exercise confirms that capture from air with the APS benchmark system or systems with comparable avoided costs is not a competitive mitigation strategy as long as the energy system contains high-carbon power, since implementation of Carbon Capture and Storage, substitution with low-carbon power and end-use efficiency will offer lower avoided-cost strategies.  相似文献   

Sources and Distribution of Particulate Organic Matter of a Tropical Estuarine-Lagoon System from NE Brazil as Indicated by Lipid Biomarkers     

Talitha L. F. Costa  Michelle P. Araújo  Bastiaan A. Knoppers  Renato S. Carreira 《Aquatic Geochemistry》2011,17(1):1-19

In the present work, we evaluated the origin of organic matter in the tropical estuarine-lagoon system of Mundaú–Manguaba, NE Brazil, by considering the bulk (organic carbon and chlorophyll-a) and lipidic (n-alcohols and sterols) composition of suspended particles. Water samples were collected in August 2006 from 24 stations covering the salinity gradient from the rivers down to the sea outlet. Chlorophyll-a (Chl-a) varied from 22.7 to 134.1 μg L⁻¹ in the lagoons, indicating eutrophic to hypertrophic conditions at the time of sampling. The high correlation between Chl-a and phytol together with the molar C:N ratio indicated the presence of fresh and recently produced autochthonous particulate organic matter throughout the system, except for the river samples. The elevated concentrations of short-chain n-alcohols and phytosterols, mainly 24-methylcholesta-5,24(28)-dien-3β-ol, also corroborated the predominance of autochthonous organic matter in the lagoons but were generated by distinct sources: cianobacteria in the freshwater Manguaba lagoon and diatoms in the brackish Mundaú lagoon compartments. Input of terrestrial organic matter was only detected in the rivers themselves or at the upper river–lagoon interfaces. Coprostanol indicated contamination by sewage in Mundaú lagoon and in some rivers, but at lower levels when compared to other Brazilian coastal lagoons and estuaries.  相似文献   

3D-electrical resistivity tomography monitoring of salt transport in homogeneous and layered soil samples   总被引：1，自引：1，他引：0  

Cesare Comina  Renato Maria Cosentini  Gabriele Della Vecchia  Sebastiano Foti  Guido Musso 《Acta Geotechnica》2011,6(4):195-203

Monitoring transport of dissolved substances in soil deposits is particularly relevant where safety is concerned, as in the case of geo-environmental barriers. Geophysical methods are very appealing, since they cover a wide domain, localising possible preferential flow paths and providing reliable links between geophysical quantities and hydrological variables. This paper describes a 3D laboratory application of electrical resistivity tomography (ERT) used to monitor solute transport processes. Dissolution and transport tests on both homogeneous and heterogeneous samples were conducted in an instrumented oedometer cell. ERT was used to create maps of electrical conductivity of the monitored domain at different time intervals and to estimate concentration variations within the interstitial fluid. Comparisons with finite element simulations of the transport processes were performed to check the consistency of the results. Tests confirmed that the technique can monitor salt transport, infer the hydro-chemical behaviour of heterogeneous geomaterials and evaluate the performances of clay barriers.  相似文献