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741.
The Adriatic carbonate platform existed throughout most of the Mesozoic as an isolated (intraoceanic) carbonate platform. It is characterized by what has been traditionally labelled a continuous shallow marine carbonate sedimentation, without terrigenous influences. However, global sea-level changes left unequivocal imprints in the continuous carbonate record, thus proving that the carbonate platform sensitively responded to sea-level fluctuations. This paper focuses on the relatively short Cenomanian — Turonian drowning event, which temporarily submerged the platform below the euphotic zone, and which is related here to the well known global Cenomanian — Turonian sea-level highstand. This drowning episode is characterized by the abrupt disappearance of numerous shallow water benthic invertebrate taxa and by an abundant occurrence of planktonic organisms, including calcispheres and primitive planktonic foraminifera. Near the middle of the Turonian, the platform regime was re-established, correlating with the global fall in sea level. The situation is different only at the south-west margin of the platform, where pelagic sedimentation, initiated near the end of the Cenomanian, continues into the Santonian and probably marks the Adriatic trough. The drowning began earlier (in the Middle Cenomanian) in those areas nearer to the north-east margin of the platform (the area of what is today central Croatia) and then progressed gradually towards the more interior areas of the platform (the middle Dalmatian islands), which were drowned near the end of the Cenomanian. 相似文献
742.
Aquifer parameter estimation using an incremental area method 总被引:2,自引:0,他引:2
Theoretical well functions have been derived over the years to predict ground water level behaviour in aquifer systems under stress owing to groundwater extraction. The drawdown data collected during pump tests are typically analysed using graphical curve‐matching procedures to estimate aquifer parameters based on these well functions. Difficulty in aquifer characteristic identification and parameter estimation may arise when the field data do not perfectly match the drawdown curves obtained from the well functions. The present study provides a new method for the interpretation of aquifer pump tests which supplements the existing curve‐matching procedures in case ideal conditions do not exist; the proposed method provides a greater degree of flexibility in the data analysis for diagnostic tool purposes. The method, referred to as the Incremental Area Method (IAM) is based on integrating the logarithmic‐based drawdown curves within a discrete time and matching the results with a corresponding time integral of the Theis ( 1935 ) Well Function which governs ideal confined aquifers. The application of the proposed method to synthetically generated data and field data showed that IAM represents a viable method which yields information on potential non‐idealness of the aquifer and provides aquifer parameter estimates thus potentially overcoming drawdown data curve‐matching difficulties. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
743.
A. Erdem F. Aliçavuş F. Soydugan S.S. Doğru E. Soydugan C. Çiçek O. Demircan 《New Astronomy》2011,16(8):498-502
This paper presents new CCD Bessell BVRI light curves and photometric analysis of the Algol-type binary star TX Her. The CCD observations were carried out at Çanakkale Onsekiz Mart University Observatory in 2010. New BVRI light curves from this study and radial velocity curves from Popper (1970) were solved simultaneously using modern light and radial velocity curves synthesis methods. The general results show that TX Her is a well-detached eclipsing binary, however, both component stars fill at least half of their Roche lobes. A significant third light contribution to the total light of the system could not be determined. Using O–C residuals formed by the updated minima times, an orbital period study of the system was performed. It was confirmed that the tilted sinusoidal O–C variation corresponds to an apparent period variation caused by the light travel time effect due to an unseen third body. The following absolute parameters of the components were derived: M1 = 1.62 ± 0.04 M⊙, M2 = 1.45 ± 0.03 M⊙, R1 = 1.69 ± 0.03 R⊙, R2 = 1.43 ± 0.03 R⊙, L1 = 8.21 ± 0.90 L⊙ and L2 = 3.64 ± 0.60 L⊙. The distance to TX Her was calculated as 155 ± 10 pc, taking into account interstellar extinction. The position of the components of TX Her in the HR diagram are also discussed. The components are young stars with an age of ~500 Myr. 相似文献
744.
This article describes and formulates a model designed to simulate runoff in wet weather events, called reservoir rainfall–runoff geomorphological model (R3GeM). In these wetlands, soil saturation is the main mechanism for the generation of surface runoff. To determine the saturated areas, the model applies a relationship based on the topographic index, between watershed storage and saturated surface. Precipitation is separated into surface runoff by saturation, subsurface runoff and losses; then, the flow of surface and subsurface runoff is performed. This hydrological model has five parameters and has been implemented in 37 events in Aixola watershed and 15 in Oiartzun watershed, both located on the Cantabrian coast of Spain. We analysed the influence of these five parameters in their behaviour, and we have proven, noting the efficiency gains, that the proposed model is valid to simulate the rainfall–runoff process. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
745.
A cluster of craterlike depressions in the central Barents Sea are several hundred meters across, have steep walls, and are cut into underlying Triassic rocks. Their formation is explained in relation to the glacial history of the region, and a possible model suggests that gas from a deeper, thermogenic source allowed a hydrate layer of considerable thickness to form during the Late Weichselian, when grounded ice covered the area and increased the hydrostatic pressure. After a rapid retreat of the marinebased ice sheet, the hydrates decomposed and the layer thinned rapidly until pressurized free gas, trapped below the hydrates, erupted and formed the sea-floor depressions. 相似文献
746.
747.
在建立大型农业气候数据库的基础上,研制了“农业气候相似信息系统”,着重介绍该系统的总体设计,原理与功能特点,开发与应用前景等。该系统可迅速查询农业气候相似研究应用动态和世界各地的气候数据;任选指标组合进行农业气候相似计算、排序、可为动、植物引种、扩种提供驯化次序和适宜范围,也可为农业技术交流和研究提供农业气候依据。 相似文献
748.
Supplier selection is a complex task which assumes decision making in presence of many conflicting criteria and various parameters. If there are more than one decision maker, the problem shifts into a group context and it requires proper approach in mediating the decision making process and use of supporting multi-criteria methods and tools. This paper proposes group decision making approach for supplier selection based on analytic hierarchy process (AHP) that is combined with consensus convergence model, and two voting methods, non-preferential approval voting and preferential Borda count. Proposed approach utilized strengths of these methods thus enabling their adaption to the specific decision problem of supplier selection. An example of selecting a supplier of irrigation equipment in the company engaged in projecting, installing and maintenance of irrigation systems is used to explain and demonstrate how proposed approach can be implemented. Furthermore, this approach is viable as sufficiently general in supporting different selection processes in a field of water planning, management, and development and it can be adapted and applied on various group decision making problems. 相似文献
749.
D. Penna M. Ahmad S. J. Birks L. Bouchaou M. Brenčič S. Butt L. Holko G. Jeelani D. E. Martínez G. Melikadze J. B. Shanley S. A. Sokratov T. Stadnyk A. Sugimoto P. Vreča 《水文研究》2014,28(22):5637-5644
We modified a passive capillary sampler (PCS) to collect snowmelt water for isotopic analysis. Past applications of PCSs have been to sample soil water, but the novel aspect of this study was the placement of the PCSs at the ground‐snowpack interface to collect snowmelt. We deployed arrays of PCSs at 11 sites in ten partner countries on five continents representing a range of climate and snow cover worldwide. The PCS reliably collected snowmelt at all sites and caused negligible evaporative fractionation effects in the samples. PCS is low‐cost, easy to install, and collects a representative integrated snowmelt sample throughout the melt season or at the melt event scale. Unlike snow cores, the PCS collects the water that would actually infiltrate the soil; thus, its isotopic composition is appropriate to use for tracing snowmelt water through the hydrologic cycle. The purpose of this Briefing is to show the potential advantages of PCSs and recommend guidelines for constructing and installing them based on our preliminary results from two snowmelt seasons. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
750.
Antonio Alfonso-Faus Màrius Josep Fullana i Alfonso 《Astrophysics and Space Science》2013,348(2):527-531
From the equivalence principle, one gets the strength of the gravitational effect of a mass M on the metric at position r from it. It is proportional to the dimensionless parameter β 2=2GM/rc 2, which normally is ?1. Here G is the gravitational constant, M the mass of the gravitating body, r the position of the metric from the gravitating body and c the speed of light. The seeable universe is the sphere, with center at the observer, having a size such that it shall contain all light emitted within it. For this to occur one can impose that the gravitational effect on the velocity of light at r is zero for the radial component, and non zero for the tangential one. Light is then trapped. The condition is given by the equality R g =2GM/c 2, where R g represents the radius of the seeable universe. It is the gravitational radius of the mass M. The result has been presented elsewhere as the condition for the universe to be treated as a black hole. According to present observations, for the case of our universe taken as flat (k=0), and the equation of state as p=?ρc 2, we prove here from the Einstein’s cosmological equations that the universe is expanding in an accelerated way as t 2, a constant acceleration as has been observed. This implies that the gravitational radius of the universe (at the event horizon) expands as t 2. Taking c as constant, observing the galaxies deep in space this means deep in time as ct, linear. Then, far away galaxies from the observer that we see today will disappear in time as they get out of the distance ct that is <R g . The accelerated expanding vacuum will drag them out of sight. This may be a valid test for the present ideas in cosmology. Previous calculations are here halved by our results. 相似文献