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991.
Sergio Mejía 《The Cartographic journal》2017,54(2):163-172
The first attempted republican map of present-day Colombia remained unachieved. Francisco José de Caldas worked on it since 1797 and, come the revolution and Nueva Granada's republican inception, he prepared two successive cartouches to introduce it: the first one in 1811, the latter in 1815. Finally entitled Provincias de la Nueva Granada, Caldas's map remains understudied. In this article, I establish its basic cartographic parameters, discuss the political context of its unfinished making and link it to its pertinent cartographic precedents. 相似文献
992.
Remote leveling of tide gauges using GNSS reflectometry: case study at Spring Bay,Australia 总被引:1,自引:1,他引:0
We further developed a new approach using GNSS reflectometry to determine the leveling connection between a tide gauge and a GNSS antenna. This approach includes the optimization of the unknown receiver bandwidth and the estimation of frequency changes in the signal-to-noise ratio (SNR) oscillation through an extended Kalman filter/smoother algorithm. We also corrected the geometric bending of the GNSS signals due to tropospheric refraction using local meteorological observations. Using 3 weeks of SNR data in Spring Bay, Australia, from a GNSS antenna placed sideways (i.e., ground plane orientated vertically and directed in azimuth toward the sea surface) to improve the SNR interference near the horizon, we obtained mean leveling differences of approximately 5 mm, with an RMS of approximately 3 cm level with respect to the nominal leveling from classical surveying techniques. SNR data from three different receiver manufacturers, coupled to the same antenna, provided similar leveling results. With a second antenna in the usual upright configuration, we obtained mean leveling differences of 1–2 cm and a RMS of about 10 cm. In the upright configuration, the leveling differences may include errors in the GNSS antenna phase center calibration, which are avoided in our technique but not in the classical surveying techniques. These results demonstrate the usefulness of the reflectometry technique to obtain precisely and remotely the leveling between a GNSS antenna and a tide gauge. In addition, this technique can be applied continuously, providing an independent and economical means to monitor the stability of the tide gauge zero. 相似文献
993.
Francisco?J.?MoralEmail author Elena?Pulido Antonio?Ruíz Fernando?López 《Theoretical and Applied Climatology》2017,129(3-4):881-889
The present work reports on a methodology to assess the climatic severity of a particular geographic region as compared to specific information available in the current regulations. The viability for each of the 387 municipalities in the Autonomous Community of Extremadura (Spain) is analysed, making a distinction between those with reliable climate reports and those for which no such information is available. In the case study, although the weather conditions in Extremadura are quite homogeneous according to the Spanish Technical Building Code (STBC 2015) classification and most areas are associated to zone C4 (soft winters and hot summers), the southern area in the region is associated to zone D1, similar to the north of Spain, where winters and summers are cool, which does not coincide with the actual climate in the south of Extremadura. The general climatic homogeneity in Extremadura was also highlighted with the new procedure, predominating zone C4, but unexpected or unreal climatic zoning was not generated, giving place to a consistent spatial distribution of zones throughout the region. Consequently, the proposed method allows a more accurate climatic zoning of any region in agreement with the Spanish legislation on energy efficiency in buildings, which would enhance the setting of thermal demand rates according to the actual climatic characterisation of the area in which a particular municipality is located. 相似文献
994.
Brázdil Rudolf Szabó Péter Dobrovolný Petr Řezníčková Ladislava Kotyza Oldřich Suchánková Silvie Valášek Hubert 《Theoretical and Applied Climatology》2017,129(1-2):623-632
Theoretical and Applied Climatology - This paper addresses the course, extent, and impacts of a windstorm that occurred on 20–21 December 1740, in the Czech Lands. The analysis is based on... 相似文献
995.
Galileo Constellation Design 总被引:2,自引:0,他引:2
Álvaro Mozo-García Esperanza Herráiz-Monseco Ana Belén Martín-Peiró Miguel M. Romay-Merino 《GPS Solutions》2001,4(4):9-15
A significant effort has been carried out in Europe to define the European Global Navigation Satellite System (GNSS), named
Galileo Satellites flying in Medium Earth Orbits (MEO) will compose the system (according to the most recent architecture
definition baseline); a regional complement of geosynchronous satellites may be required to increase performances over Europe
and maybe also to provide some specific communication services. Nominal medium performances are envisaged, but they will be
increased by means of augmentation systems (local or wide area), or even by using simultaneously other GNSSs such as GPS.
All the involved requirements make the design process quite complex. A powerful software tool, Elcano, has been developed
for this purpose; its capabilities will be outlined, and the results of the design process will be presented. ? 2001 John
Wiley & Sons, Inc. 相似文献
996.
Gold has been exploited intensively in the Brazilian Amazon during the past fifteen years using garimpo methods (small-scale gold mining). In this study, two gold mining areas were investigated, the municipalities of Pocone and Alta Floresta located in the state of Mato Grosso. Central Brazil. The elemental mercury (Hg) used in amalgamating the gold, the final stage of the ore dressing process, has caused abnormal Hg concentrations in waterways. This has occurred principally in the Amazon region, where most of the ore prospected is alluvial. Background levels of metals were determined by analyzing sediments and soils located upstream of the anthropogenic inputs and unaffected by mining activities. The study aimed to evaluate the pollution level in sediments and soils, taking into account drainage waters directly affected by gold mining. ‘Geoaccumulation indexes’ (Igeo) of Hg in sediments from both study areas were used to assesses the pollution level in the aquatic environment. The geoaccumulation indexes of Hg in sediments of the Bento Gomes River in Pocone indicate a relatively high degree of pollution at some sites, even reaching class 4 (1.85 mg/kg). However, when the river reaches the Pantanal swamp, Hg concentrations drop considerably to 0.30 mg/kg. This drop seems to be due to accumulation of metals in the sediments of a lake (sampling site PG-24), which retains most of the sediments transported by the Bento Gomes River. Accumulation of metals in the lake also occurred for Cu, Pb, Zn, Fe and Mn. In the region of Alta Floresta, total Hg concentrations in sediments of the Teles Pires River were studied in the grain size fractions < 74 μm and > 74 μm. Hg concentrations in bottom sediments of this river were higher than those found in the Pocone region, with increases of 1.5 to 30 times the background, and thus reaching an Igeo up to class 5. 相似文献
997.
B. Kříbek 《Mineralium Deposita》1991,26(2):122-131
Accumulation of metals in anoxic environments occurs by sorption and precipitation from seawater, fossil brines or hydrothermal solutions. Metals can be remobilized during subsequent metamorphic and magmatic processes and form ore deposits. This type of mineralization is governed chiefly by the type of tectonic setting of the anoxic environment. Carbonaceous sediments of passive margins contain only subeconomic concentrations of uranium, vanadium and molybdenum. Cubearing black shales and the submarine-exhalative type of mineralization are confined to the environments of continental rifts and aulacogens or to back-arc basins of active margins. Metamorphogenic deposits are mainly connected with collision margins but they may also occur in other types of tectonic environments. The formation of Cu-bearing black shales was controlled by period of low sea-level during the break-up of supercontinents in the Earth's evolution. Increased contents of uranium and vanadium accumulated in black shales in periods of sealevel highstands. Lithological control is apparent in deposits of Cu-bearing and uraniferous black shales. On the contrary, the occurrence of polymetallic mineralization does not depend on the lithological maturity of carbonaceous sediments. 相似文献
998.
999.
In this paper a computerized method for the intensity estimation from macroseismic observations is presented. The successive steps of the MSK intensity scale (2° to 10°) receives weights according to the observations marked on the earthquake questionnaires. These weights are summed for the individual scale steps. The distribution of these summed weights and their relation to an experimentally chosen function of the criterion make it possible to estimate the appropriate intensity value and its reliability. By computer evaluation of earthquake reports an objective comparison of estimated intensities given by different seismologists can be made, provided that uniform earthquake questionnaires are used. The application of this method will result in more homogeneous intensity data. 相似文献
1000.
In the western part of the Cantabrian Zone, Carlés gold mineralization is related to an igneous stock of granodioritic composition which intruded into devonian limestones, forming a well-developed exo-skarn and quantitatively less important endo-skarn. The skarn is characterized by the presence of garnet, pyroxenes, amphiboles, layers of hornfels corresponding to pelitic intercalations, and a number of opaque oxides and sulfides. Gold inclusions in arsenic minerals are present in quartzveins occurring in the skarn and in the granodiorite, but gold-rich zones are limited to the skarn. The crystallization temperature of arsenopyrite is coherent with T-P conditions (T = 460°C, P = 2200 bars) deduced from intersections of isochores of aqueous and carbonic fluid inclusions studied in samples of cogenetic quartz. 相似文献