PRAÇAS,PLACE, AND PUBLIC LIFE IN URBAN BRAZIL*     

James R. Curtis 《Geographical review》2000,90(4):475-492

ABSTRACT. This study interprets critical stages in the changing design and landscape of urban squares, or praças, in Brazil and assesses the circumstances of their cultural‐historical production. Urban squares were shaped by, and in the process contributed to and shed light on, several of the country's major social and artistic movements. The history of the square illustrates a theme of European cultural dominance, especially French, that was a product of the colonial experience and neocolonial influences which were overcome only in the twentieth century through spontaneous creative fusion with indigenous Brazilian elements.  相似文献   

Bidirectional reflectance distribution function measurements of the Winchcombe meteorite using the Visible Oxford Space Environment Goniometer     

R. J. Curtis  H. C. Bates  T. J. Warren  K. A. Shirley  E. C. Brown  A. J. King  N. E. Bowles 《Meteoritics & planetary science》2024,59(5):1029-1042

A laboratory study was performed using the Visible Oxford Space Environment Goniometer in which the broadband (350–1250 nm) bidirectional reflectance distribution function (BRDF) of the Winchcombe meteorite was measured, across a range of viewing angles—reflectance: 0°–70°, in steps of 5°; incidence: 15°, 30°, 45°, and 60°; and azimuthal: 0°, 90°, and 180°. The BRDF dataset was fitted using the Hapke BRDF model to (1) provide a method of comparison to other meteorites and asteroids, and (2) to produce Hapke parameter values that can be used to extrapolate the BRDF to all angles. The study deduced the following Hapke parameters for Winchcombe: w = 0.152 ± 0.030, b = 0.633 ± 0.064, and h_S = 0.016 ± 0.008, demonstrating that it has a similar w value to Tagish Lake (0.157 ± 0.020) and a similar b value to Orgueil (0.671 ± 0.090). Importantly, the surface profile of the sample was characterized using an Alicona 3D® instrument, allowing two of the free parameters within the Hapke model φ and $\overline{\theta }$, which represent porosity and surface roughness, respectively, to be constrained as φ = 0.649 ± 0.023 and $\overline{\theta }$ = 16.113° (at 500 μm size scale). This work serves as part of the characterization process for Winchcombe and provides a reference photometry dataset for current and future asteroid missions.  相似文献   

Oscillatory instability of radiative shocks with multiple cooling processes     

Curtis J. Saxton  Kinwah Wu  Helen Pongracic  & Giora Shaviv 《Monthly notices of the Royal Astronomical Society》1998,299(3):862-876

The stand-off shock formed in the accretion flow on to a stationary wall, such as the surface of a white dwarf, may be thermally unstable, depending on the cooling processes which dominate the post-shock flow. Some processes lead to instability, while others tend to stabilize the shock. We consider competition between the destabilizing influence of thermal bremsstrahlung cooling, and a stabilizing process which is a power law in density and temperature. Cyclotron cooling and processes which are of order 1, 3/2 and 2 in density are considered. The relative efficiency and power-law indices of the second mechanism are varied, and particular effects on the stability properties and frequencies of oscillation modes are examined.  相似文献   

Bioremediation in Fractured Rock: 1. Modeling to Inform Design,Monitoring, and Expectations          下载免费PDF全文

Claire R. Tiedeman  Allen M. Shapiro  Paul A. Hsieh  Thomas E. Imbrigiotta  Daniel J. Goode  Pierre J. Lacombe  Mary F. DeFlaun  Scott R. Drew  Carole D. Johnson  John H. Williams  Gary P. Curtis 《Ground water》2018,56(2):300-316

Field characterization of a trichloroethene (TCE) source area in fractured mudstones produced a detailed understanding of the geology, contaminant distribution in fractures and the rock matrix, and hydraulic and transport properties. Groundwater flow and chemical transport modeling that synthesized the field characterization information proved critical for designing bioremediation of the source area. The planned bioremediation involved injecting emulsified vegetable oil and bacteria to enhance the naturally occurring biodegradation of TCE. The flow and transport modeling showed that injection will spread amendments widely over a zone of lower‐permeability fractures, with long residence times expected because of small velocities after injection and sorption of emulsified vegetable oil onto solids. Amendments transported out of this zone will be diluted by groundwater flux from other areas, limiting bioremediation effectiveness downgradient. At nearby pumping wells, further dilution is expected to make bioremediation effects undetectable in the pumped water. The results emphasize that in fracture‐dominated flow regimes, the extent of injected amendments cannot be conceptualized using simple homogeneous models of groundwater flow commonly adopted to design injections in unconsolidated porous media (e.g., radial diverging or dipole flow regimes). Instead, it is important to synthesize site characterization information using a groundwater flow model that includes discrete features representing high‐ and low‐permeability fractures. This type of model accounts for the highly heterogeneous hydraulic conductivity and groundwater fluxes in fractured‐rock aquifers, and facilitates designing injection strategies that target specific volumes of the aquifer and maximize the distribution of amendments over these volumes.  相似文献   

Bioremediation in Fractured Rock: 2. Mobilization of Chloroethene Compounds from the Rock Matrix          下载免费PDF全文

Allen M. Shapiro  Claire R. Tiedeman  Thomas E. Imbrigiotta  Daniel J. Goode  Paul A. Hsieh  Pierre J. Lacombe  Mary F. DeFlaun  Scott R. Drew  Gary P. Curtis 《Ground water》2018,56(2):317-336

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Quarternary glaciations in the northern hemisphere,V. Sibrava,D.Q. Bowen,and G.M. Richmonds,Eds., 1986, Quaternary Science Reviews,Vol. 5, Pergamon Press,Oxford, 510 p. $100.00 (hardback)     

Curtis E. Larsen 《Geoarchaeology》1989,4(1):86-90

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