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961.
Measurements with Piche evaporimeters have been conducted within a thermometer screen over a grass surface at several heights. The results show a good correlation with model calculations but differ somewhat in absolute value. Comparisons with the Penman potential evaporation results show a considerable overestimation. With a simple factor, or with a lower measuring position, the results can be brought in a better agreement. The idea of G. Stanhill was verified and proved to be useful only for long periods. 相似文献
962.
R. Sigbjörnsson J. Th. Snæbjörnsson S. M. Higgins B. Halldórsson S. Ólafsson 《Bulletin of Earthquake Engineering》2009,7(1):113-126
This preliminary study aims to investigate a M
w
6.3 earthquake that occurred in South Iceland on Thursday 29 May 2008 at 15:45 UTC. The epicentre was in the Olfus District
between the towns of Selfoss and Hveragerdi. This study examines the data recorded and the damage observed immediately after
the event. Horizontal accelerations of up to 80%g were recorded in the epicentral region and there is visual evidence that
the vertical acceleration exceeded 1 g. The PGA data is compared to a ground motion estimation model developed for the South
Iceland earthquakes in June 2000. In general the basic properties of this event are found to be similar to the characteristics
of the South Iceland earthquakes in June 2000. The duration of strong-motion is short and the intensity attenuates rapidly
with increasing distance. The earthquake action resisted by buildings in the near fault area is inspected through evaluation
of elastic as well as inelastic response spectra. The vast majority of structures seemed to withstand the strong-motion fairly
competently and without significant visual damage due firstly to the low-rise, predominantly reinforced concrete or timber,
style of buildings. Secondly, the short duration of strong-motion contributed to the endurance of structures. 相似文献
963.
The influence of wave–bedform feedbacks on both the initial formation of shoreface-connected sand ridges (sfcr) and on grain
size sorting over these ridges on micro-tidal inner shelves is studied. Also, the effect of sediment sorting on the growth
and the migration of sfcr is investigated. This is done by applying a linear stability analysis to an idealized process-based
morphodynamic model, which simulates the initial growth of sfcr due to the positive coupling between waves, currents, and
an erodible bed. The sediment consists of sand grains with two different sizes. New elements with respect to earlier studies
on grain sorting over sfcr are that wave-topography interactions are explicitly accounted for, entrainment of sediment depends
on bottom roughness, and transport of suspended sediment involves settling lag effects. The results of the model indicate
that sediment sorting causes a reduction of the growth rate and migration speed of sfcr, whereas the wavelength is only slightly
affected. In the case where the entrainment of suspended sediment depends on bottom roughness, the coarsest sediment is found
in the troughs; otherwise, the finest sediment occurs in the troughs. Compared to previous work, modeled maximum variations
in the mean grain size over the topography are in better agreement with field observations. Settling lag effects are important
for the damping of high-wavenumber mode instabilities such that a preferred wavelength of the bedforms is obtained. 相似文献
964.
Summary The present note, as its title implies, is concerned with the investigation of disturbances in an infinite elastic medium containing an initial magnetic field in the axial direction. The equations ofMaxwell, those of elasticity have been effectively made use of to solve the problem. 相似文献
965.
B.A. Mamedov 《New Astronomy》2012,17(3):353-355
A simple evaluation algorithm for calculation of the fermions and bosons relativistic thermodynamic functions with high accuracy is presented. This method is based on the use of the binomial expansion theorems and incomplete Gamma functions. The importance of this result is that it enables a series analytical formula to determine the thermodynamic functions of fermions and bosons in cases of degeneracy and relativity. The formulas obtained are numerically stable for ψ < 0. Examples of comparative calculations are given. Numerical results verify the effectiveness of the present approach and they are in good agreement with literature. 相似文献
966.
967.
This study is a search for a genetic relationship between Pb sulphide ore and igneous rocks in the region of Mount Isa, Queensland. The approach involves derivation of Pb isotope initial ratios by the whole-rock isochron method, and comparison of the initial ratios (Pb206/Pb204, Pb207/Pb204 and Pb208/Pb204) with the isotopic composition of the ore Pb. Data are reported for four igneous units; Kalkadoon granodiorite, Kalkadoon adamellite, Sybella granite and Eastern Creek volcanics. The results display considerable scatter for each of the units, and reveal the effects of recent surficial loss of U. The positioning of isochrons is aided by previous Rb-Sr geochronological data wherever possible. Comparison of initial ratios and ore Pb suggests that none of the igneous rock units is co-genetic with the ore deposit. Both phases of the Sybella Granite are more radiogenic and are apparently younger than the ore Pb. The Kalkadoon Granite is possibly related to the ore through some post-emplacement process of extraction and transport of Pb (e.g. by erosion or by anatectic magma generation) to the present site of the orebodies. 相似文献
968.
T. W. Krauss A. A. Sin’kevich N. E. Veremei Yu. A. Dovgalyuk V. S. Makitov V. D. Stepanenko 《Russian Meteorology and Hydrology》2011,36(2):102-111
Basing on airmass motion trajectory calculations over the Arabian Peninsula on April 10, 2008, it can be assumed that in the lower and middle troposphere, zones with increased air moisture exist due to air inflow from the Red Sea. As a result, mesoscale volumes of dry and moist air are neighboring, though large-scale field is comparatively homogeneous with low humidity. In the mesoscale zones, intense thunderstorm and hailstorm Cb clouds developed, whose characteristics and evolution are studied in the paper. Continuous radar observations of the clouds are carried out during 5 hours. Numerical simulation of the cloud evolution is performed with nonstationary 1.5-dimensional model. It is noted that under the mentioned atmospheric conditions, in the area under consideration, heavy rain and hail from the Cb clouds are observed. The main factors of their origination are high thermal instability of the atmosphere and moist air inflow from outside. 相似文献
969.
This article critically engages with the recent diffusion of the orthodox development model in Oceania and highlights some evolving dilemmas. In particular, it explores the social, economic and ecological tensions arising from economic reforms that are exacerbating the fragility of already vulnerable nation-states and communities. In order to illustrate its arguments, a case study of the impacts of agro-export growth in Tonga is presented. Attention is drawn to the socially inequitable and ecologically unsustainable outcomes of rapid growth in this sector. In analyzing the political economy of the squash pumpkin sector, the authors point to the important role that culture plays in mediating and conditioning development outcomes. Reflecting on the Tongan case, it is argued that to better understand the implications of orthodox developmental reform in the region, research must seek to more explicitly incorporate distributional and ethical analysis. 相似文献
970.