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901.
Likhacheva Anna Yu. Rashchenko S. V. Musiyachenko Kira A. Korsakov Andrey V. Collings Ines E. Hanfland Michael 《Mineralogy and Petrology》2019,113(5):613-623
Mineralogy and Petrology - The structural behaviour of maruyamaite (K-dominant tourmaline) X(K0.54Na0.28Ca0.19)Y(Mg1.3Al1.17Fe0.39Ti0.14)Z(Al5Mg)[Si5.95Al0.05O18](BO3)3V,W[O1.69(OH)2.31] from the... 相似文献
902.
The modeling of tethering elements of seabed anchored floating structures is addressed, with particular reference to the so‐called Archimedes Bridge (submerged floating tunnel, SFT) solution for deep water crossing; attention is devoted to the design solution encompassing slender bars as anchor elements. Two numerical tools are proposed: firstly, a geometrically nonlinear finite element (NWB model), developed in previous work, has been refined in order to capture the effect of higher flexural modes of anchor bars. Secondly, a 3D beam element, based on the classical corotational formulation (CR model), has been developed and coded. Both elements are implemented in a numerical procedure for the dynamic time domain step‐by‐step analysis of nonlinear discretized systems; seismic loading is introduced by generating artificial time histories of spatially variable seismic motion. An example of application of the NWB element is shown regarding the behavior of the dynamic model of a complete SFT. The model was subjected to extreme multiple‐support seismic loading. The seismic behavior is here illustrated and commented, especially in light of the effect of higher local vibration modes of the anchor bars. Finally, a comparison between the performances of the two modeling approaches is presented. Both harmonic and seismic excitations are considered in the test; the results justify the use of the simpler NWB approach, especially in the SFT design phase. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
903.
The rise of the transnational veiling-fashion industry in Turkey has taken place within the context of neoliberal economic restructuring, the subjection of the veil to new regulations, and the resurgence of Islamic identities worldwide. Even after almost two decades since its first catwalk appearance, the idea of 'veiling-fashion' continues to be controversial, drawing criticism from secular and devout Muslim segments of society alike. Analysing veiling-fashion as it plays out across economic, political and cultural fields is to enter into a new understanding of the role of Islam in the global arena today. Veiling-fashion crystallises a series of issues about Islamic identity, the transnational linkages of both producers and consumers, and the shifting boundaries between Islamic ethics and the imperatives of neoliberal capitalism. In this paper, our overarching argument is that controversies and practices surrounding veiling-fashion show how Islamic actors are adapting and transforming neoliberal capitalism at the same time as they navigate a complex geopolitical terrain in which Islam – and the iconic Muslim, headscarf-wearing woman – has been cast as a threatening 'Other'. Thus the rise of veiling-fashion as a transnational phenomenon positions women and women's bodies at the centre of political debates and struggles surrounding what it means to be 'modern' and Muslim today. Based on interviews with producers, consumers and salesclerks, and our analysis of newspaper articles, catalogues and web sites, this article traces out how the transnational production, sale and consumption of veiling-fashion works to order spaces of geopolitics, geo-economics and subject formation . 相似文献
904.
Tatiana Anna Maria Quarta 《Geophysical Prospecting》2009,57(4):527-542
The Euler deconvolution is the most popular technique used to interpret potential field data in terms of simple sources characterized by the value of the degree of homogeneity. A more recent technique, the continuous wavelet transform, allows the same kind of interpretation. The Euler deconvolution is usually applied to data at a constant level while the continuous wavelet transform is usually applied to the points belonging to lines (ridges) connecting the m -order partial derivative modulus maxima of the upward-continued field at different altitudes in the harmonic region. In this paper a new method is proposed that unifies the two techniques. The method consists of the application of Euler's equation to the ridges so that the equation assumes a reduced form. Along each ridge the ratio among the m -order partial derivative of the field and its vertical partial derivative, for isolated source model, is a straight line whose slope and intercept allows the estimation of the source depth and degree of homogeneity. The method, strictly valid for single source model, has also been applied to the multisource case, where the presence of the interference among the field generated by each single source causes the path of the ratio to be no longer straight. The method in this case gives approximate solutions that are good estimations of the source depth and its degree of homogeneity only for a restricted range of altitudes, where the ratio is approximately linear and the source behaves as if it were isolated. 相似文献
905.
Plankton community as an indicator of water quality in tropical shrimp culture ponds 总被引:5,自引:0,他引:5
Casé M Leça EE Leitão SN Sant Anna EE Schwamborn R de Moraes Junior AT 《Marine pollution bulletin》2008,56(7):1343-1352
The plankton was examined as an indicator of water quality in 14 shrimp Litopenaeus vannamei farms in Brazil in 2003. The ponds were categorized by high stocking density (>30 PL m−2) of phytoplankton, consisting of 51 species with concentrations ranging from 365,218 ± 416,615 cells mL−1 to 1,961,675 ± 3,160,172 cells mL−1. Diatoms contributed to almost 70% of the species number and high densities resulted from Cyanophyta blooms, mainly Pseudanabaena cf limnetica. Forty zooplankton taxa were registered and were essentially composed of typical marine euryhaline species and suspension-feeders. Copepoda dominated (45%) the make-up, followed by Protozoa (18%), Rotifera (12%), and Mollusca (12%) larvae. Zooplankton varied from 972 ± 209 ind m−3 to 4235 ± 2877 ind m−3. Enhanced nutrient input affected plankton density and composition. Diatom and Copepoda dominance was replaced by cyanobacteria, protozoan, and rotifers as nutrient concentrations increased with the cultured period, indicating that plankton structure is affected by eutrophic conditions. 相似文献
906.
Shaun Rmer Henrik Breuning‐Madsen Thomas Balstrm Anna‐Elisabeth Jensen 《Geoarchaeology》2006,21(1):113-124
Archaeological sites dating to the Ertebolle period of the Mesolithic have been recorded below a thin layer of marine sands in a reclaimed bay on northern Falster Island in Denmark. The finds seemed randomly distributed throughout the bay; there was no obvious pattern related to the modern landscape. However, by coring through the veneer of marine sands and mapping the pattern of the underlying Late Quaternary deposits, the authors were able to reconstruct the Mesolithic landscape and thereby explain the distribution of archaeological sites. This approach allows archaeologists to focus subsurface exploration in geomorphic settings, such as former fjords and coastlines that have a high potential for yielding prehistoric sites. © 2006 Wiley Periodicals, Inc. 相似文献
907.
A Study of the Groundwater Reservoirs and Regulation in the Alluvial Fan of the Hutuo River 下载免费PDF全文
Based on analysis of the geology and hydrogeology of the alluvial fan of the Hutuo River, Hebei province of China, this paper studies the groundwater reservoir’s regulated space, storage capacity and regulated water in system. On this basis, a groundwater numerical simulation model was established. Using this model and taking into account specific regulating schemes, this paper evaluates the regulation and storage capacity of groundwater reservoirs and the effect of conjunct-tive operation of surface water and groundwater. Results show that the funnel area of the study area status storage space is 12.83×108m3. Groundwater level after the regulation has clearly rebounded; improving groundwater supply and ensuring stable water supply in Shijiazhuang city of Hebei province, this clearly has important practical significance. 相似文献
908.
Anna?Rych?a Peter?Casper Peter?KasprzakEmail author 《Aquatic Sciences - Research Across Boundaries》2012,74(1):133-142
Although anaerobic metabolism in lake sediments is strongly related to organic material from the trophogenic layer, little
is known about the role of food web structure in this respect. We tested the influence of planktivorous fish (treatments with
or without fish, ±F) and nutrients (treatments with or without fertilization, ±N) on chlorophyll a, zooplankton, sedimentation
of particulate organic carbon (POC), and methane accumulation in large enclosures with anoxic hypolimnia (10 m diameter, 8 m
deep, 2 × 2 factorial design). Additionally, methane production potential from settled material was estimated in laboratory
experiments. In the enclosures, methane accumulation rate increased in the order +F/−N, −F/+N, −F/−N, and +F/+N, while POC
sedimentation was similar in all treatments. Settled POC was more efficiently transformed into methane in −F/−N than in +F/−N
treatments. However, an opposite effect was observed between −F/+N and +F/+N treatments. In the laboratory, methane production
potential was higher when (1) POC content in settled matter increased, and (2) no fish were present. This corresponded well
only to field results obtained in −F/−N and +F/−N treatments. The unexpectedly high methane accumulation in the +F/+N treatment
was very likely related to abrupt depletion of other electron acceptors in the hypolimnion, which attenuated effects of food
web structure. In conclusion, our results indicate that food web structure indirectly affects anaerobic microbial activity
primarily due to changes in the decomposition potential of settled organic matter. 相似文献
909.
Naomi Greenwood Rodney M. Forster Veronique Créach Suzanne J. Painting Anna Dennis Stewart J. Cutchey Tiago Silva David B. Sivyer Tim Jickells 《Ocean Dynamics》2012,62(2):307-320
The seasonal and interannual variability in the phytoplankton community in Liverpool Bay between 2003 and 2009 has been examined
using results from high frequency, in situ measurements combined with discrete samples collected at one location in the bay.
The spring phytoplankton bloom (up to 29.4 mg chlorophyll m−3) is an annual feature at the study site and its timing may vary by up to 50 days between years. The variability in the underwater
light climate and turbulent mixing are identified as key factors controlling the timing of phytoplankton blooms. Modelled
average annual gross and net production are estimated to be 223 and 56 g C m−2 year−1, respectively. Light microscope counts showed that the phytoplankton community is dominated by diatoms, with dinoflagellates
appearing annually for short periods of time between July and October. The zooplankton community at the study site is dominated
by copepods and use of a fine mesh (80 μm) resulted in higher abundances of copepods determined (up to 2.5 × 106 ind. m−2) than has previously reported for this location. There is a strong seasonal cycle in copepod biomass and copepods greater
than 270 μm contribute less than 10% of the total biomass. Seasonal trends in copepod biomass lag those in the phytoplankton
community with a delay of 3 to 4 months between the maximum phytoplankton biomass and the maximum copepod biomass. Grazing
by copepods exceeds net primary production at the site and indicates that an additional advective supply of carbon is required
to support the copepod community. 相似文献
910.
Marini M Betti M Grati F Marconi V Mastrogiacomo AR Polidori P Sanxhaku M 《Marine pollution bulletin》2012,64(3):472-478
This study aimed to analyze the impact at sea of a pesticide factory located 7 km north of Durres (Albania) by investigating a lowland area under the sea situated 0.7 km from the shoreline. The main product of this factory was lindane. Production ceased in 1991 during the Albanian civil war, and a large amount of industrial waste was dispersed over the ground surrounding the factory, resulting in a high level of lindane pollution. A water-scoop channels the ground water accumulated around the disused factory directly into the sea. The concentrations of lindane in sediments collected along the coasts of the region ranged from 0.60 to 22.55 ng g(-1). The average concentration in the muscles of fish did not exceed the limits specified by European Commission legislation, whereas the concentration in the liver did exceed these limits; consequently, liver is not recommended for consumption. 相似文献