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1.
Katarzyna Skolasińska 《Hydrogeology Journal》2006,14(6):1005-1017
Long-term water infiltration into porous media, like clastic deposits, causes colmatage (clogging), which is expressed by the decrease of permeability. It is caused by progressive filling of pore spaces with fine particles carried in suspension (mechanical colmatage) and minerals precipitated from water (chemical colmatage or biochemical colmatage, when the process is affected by bacterial activity). Although this material is introduced into the sediment after deposition, it does not destroy the primary framework of it but it only coats grains and fills voids. This process results in some characteristic microstructures that are called ‘clogging microstructures’. The research included: (1) experiments on sands exposed to mechanical colmatage in laboratory conditions, which aimed to describe clogging microstructures and to examine the effects of grain size distribution on the rate and degree of clogging; (2) field and laboratory studies of deposits in which colmatage occurred in natural conditions in the infiltrating water intake ‘Dębina’ in Poznań, Poland. The main goal of the research was to identify post-depositional changes that took place in fluvial deposits affected by forced river water infiltration in the Warta River valley. Examples are presented of clogging microstructures formed in deposits affected by colmatage in the laboratory and in natural conditions.
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| Katarzyna SkolasińskaEmail: Fax: +48-618-296001 |
2.
The present state-of-the-art for natech risk and management is discussed. Examples of recent natechs include catastrophic
oil spills associated with Hurricane Katrina and hazardous chemical releases in Europe during the heavy floods of 2002. Natechs
create difficult challenges for emergency responders due to the geographical extent of the natural disaster, the likelihood
of simultaneous releases, emergency personnel being preoccupied with response to the natural disaster, mitigation measures
failing due to the effects of the natural disaster, and others. Recovery from natechs may be much more difficult than for
“normal” chemical accidents, as the economic and social conditions of the industrial facility and the surrounding community
may have been drastically altered by the natural disaster. Potential safeguards against natechs include adoption of stricter
design criteria, chemical process safeguards, community land use planning, disaster mitigation and response planning, and
sustainable industrial processes, but these safeguards are only sporadically applied. Ultimately, the public must engage in
a comprehensive discussion of acceptable risks for natechs.
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| Ana Maria CruzEmail: |
3.
P. Mogilevsky 《Physics and Chemistry of Minerals》2007,34(3):201-214
The regular solid solution model has been applied to solid solubility in the monazite–xenotime systems and is verified against
the available experimental data for LaPO4–YPO4 and CePO4–YPO4 systems. The model is then used to predict the miscibility gaps in a number of other monazite–xenotime systems. The implications
for prospective two-phase monazite–xenotime fiber coatings for applications in ceramic matrix composites (CMCs) are discussed.
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| P. MogilevskyEmail: |
4.
Metal cycling via physical and chemical weathering of discrete sources (copper mines) and regional (non-point) sources (sulfide-rich shale) is evaluated by examining the mineralogy and chemistry of weathering products in Great Smoky Mountains National Park, Tennessee, and North Carolina, USA. The elements in copper mine waste, secondary minerals, stream sediments, and waters that are most likely to have negative impacts on aquatic ecosystems are aluminum, copper, zinc, and arsenic because these elements locally exceed toxicity guidelines for surface waters or for stream sediments. Acid-mine drainage has not developed in streams draining inactive copper mines. Acid-rock drainage and chemical weathering processes that accompany debris flows or human disturbances of sulfidic rocks are comparable to processes that develop acid-mine drainage elsewhere. Despite the high rainfall in the mountain range, sheltered areas and intermittent dry spells provide local venues for development of secondary weathering products that can impact aquatic ecosystems.Electronic Supplementary Material Supplementary material is available for this article if you access the article at . A link in the frame on the left on that page takes you directly to the supplementary material.
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| Jane M. HammarstromEmail: Phone: +1-703-6486165Fax: +1-703-6486252 |
5.
This paper describes an application of the geographic information system (GIS) technology to a ground stability assessment
in the karst area of Dzerzhinsk, Russia. In the stability analysis, the groundwater level changes in the karst aquifer could
cause suffosion sinkholes when the gravitational force was greater than the soil strength. The GIS technology was used to
combine various data and to delineate the zones of potential gravitational collapse and suffosion collapse in the area.
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| V. V. TolmachevEmail: |
6.
Summary The question of alternative technologies for high-speed Internet access lies at the heart of rural development problems. In
this paper, we focus on one of those technologies, the system combining satellite technologies and Wi-Fi. Based on an empirical
study carried out in three rural areas, we analyze the dynamics of the use and appropriation of that technology by the companies
and organizations participating in the experiment. Considered both from a technical and social standpoint, the technology
‘in use’ appears here in its structuring dimensions.
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| Valérie FautreroEmail: |
7.
Modeling stream-aquifer interactions in a shallow aquifer, Choele Choel Island, Patagonia, Argentina 总被引：3，自引：1，他引：2
A groundwater/surface-water interaction model was developed for the shallow alluvial aquifer of the Choele Choel Island in
Patagonia, Argentina. In this semiarid climate, agriculture is sustained by an irrigation/drainage system. During the irrigation
season, seepage losses through unlined distribution canals in irrigated fields contribute to elevated groundwater levels,
jeopardizing fruit productivity in some areas. Moreover, high stream stages during the irrigation season interfere with groundwater
drainage. The model utilized MODFLOW and its stream package, and was successfully calibrated for a historical irrigation season.
Modeling results indicate that drainage through streams is significantly higher than drainage through artificial drains. The
stream/aquifer relationship proved very responsive to water table rises caused by irrigation. This response manifested as
changes in the gaining/losing character of stream reaches. A synthetic run aimed at isolating the effect of streamflow changes
on groundwater levels showed that the effect of higher streamflows dissipates toward the interior of the island, disappearing
completely at the island center. Even though some results were qualitative, the model helped to provide a better understanding
of the coupled system to elucidate some of the causes of a rising water table on the island.
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| Leticia B. RodríguezEmail: |
8.
This study seeks to gauge how far China’s container-related dynamics between 1990 and 2005 fit into the wider perspective
about transport and development within developing countries. In particular, attention is focussed on the role of specific
modes to determine the extent of the penetration of containers within China. Before addressing these key issues extant models
relating to an understanding of port and transport evolution in less-developed countries are recalled, synthesized and used
as a base upon which an appropriate review of China’s case can be conducted. Applying them to China’s northern, central and
southern port ranges not only helps assess the efficacy of these models but also highlights the contribution of individual
modes.
相似文献
| Claude ComtoisEmail: |
9.
Contract farmers in central Honduras have been producers of Asian vegetables for American markets since 1989. Contract farming
holds the potential to provide benefits to small farmers who would otherwise be unable to access export markets but production
relations between firms and farmers are often asymmetric and can be exploitative. Poor communication and legacies of mistrust
between commodity agriculture and small farmers lead to ambiguities in the contracting system that are misinterpreted by both
firms and farmers, creating social tensions between contracting parties. This article will consider how farmers’ navigation
of the contracting system and competition between export firms has led to changes in the system. Through competition for a
limited pool of outgrowers, firms adjust their policies in favor of farmers without explicit attempts of labor organization
on the part of the farmers.
相似文献
| Valerie ImbruceEmail: |
10.
Dorian Speakman 《Natural Hazards》2008,44(1):111-127
A vulnerability index for the Fire Service in the UK has been designed to identify vulnerable locations during episodes of
severe floods. Taking recent case studies with the UK Fire Service, the patterns of vulnerability, in terms of demand on time
and resources, can be explained by investigating the environmental causes and their interaction with the adaptive capacity
of the response agencies.
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| Dorian SpeakmanEmail: |
11.
Igor Vojnovic 《GeoJournal》2007,69(4):271-300
Throughout the 20th century, government in the U.S. has gone through significant changes; initially responding to the disorder
of early capitalism, and later, to the economic crisis of the 1970s. This article will explore the changes in the U.S. political
landscape over the last century, as well as the recent rise of neo-liberalism. In addition, with the analysis of the model
laissez-faire municipal government, the City of Houston, the article will illustrate how the basic weaknesses of neoliberalism
at the national level are also evident at the local scale of government.
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| Igor VojnovicEmail: |
12.
Geographers show keen interest in projected images employed in tourism as these images both reflect the ideas of the image
producers and influence tourists’ perceptions and (spatial) behaviour. This article focuses on intentional and unintentional
projected images of the Netherlands. The former is especially selective: it relies on stereotypes and presents Holland. The
unintentional projected image created in four travel guides is less stereotyped. While the focus is still on Holland, other
areas of the country are presented as well. Both intentional and unintentional projected images rely on ’othering’ and ’alterity’
to make the Netherlands a unique destination and to offer the tourists a trip that is far from everyday life. However travel
guides use ’alterity’ in different ways and at different levels of scale to create a regional geography of the Netherlands
as well.
相似文献
| Bouke van GorpEmail: |
13.
Melt inclusion formation mechanisms and compositional effects in high-An feldspar and high-Fo olivine in anhydrous mafic silicate liquids 总被引：1，自引：1，他引：0
Important aspects of melt inclusion formation and potential compositions effects have been addressed through a series of experiments using anorthite/fosterite saturated anhydrous mafic liquids. Experimental charges were cooled from 1,300 to 1,230 and 1,210°C at rates of 1–10°/min followed by 0–24 h isothermal periods. Hopper and skeletal crystal morphologies with variable degrees of completeness developed during the cooling period. Planar overgrowth of these textures during isothermal periods led to the formation of inclusions, the majority of which formed after 6 h of isothermal run time. We suggest that the change in morphologies is related to a decrease in growth rates and changes in dominant growth mechanisms. In general, inclusion compositions were uniform and similar to the host glass, indicating that with the isothermal times required for most inclusions to form, a boundary layer was not entrapped that could be detected within the limits of our analyses.
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| Edward KohutEmail: Phone: +1-541-7373023Fax: +1-541-7371200 |
| Roger L. NielsenEmail: Phone: +1-541-7371235 |
14.
David Havlick 《GeoJournal》2007,69(3):151-164
Since 1988, more than 20 US military bases have been redesignated as national wildlife refuges. In order to understand the
processes of these military-to-wildlife (M2W) conversions and their implications, I examine three logics that help to produce
these particular changes: Biodiversity, Brownfields, and Serendipity. These logics contribute to a broader discourse of ecological
militarization that frames military practices as compatible with and contributing to environmental protection. I focus on
the case of the Rocky Mountain Arsenal, Colorado, USA, to examine how these logics of conversion are mobilized into practice,
and what such changes mean as they bring militarism and environmental conservation together in reconfigured spaces.
相似文献
| David HavlickEmail: |
15.
The Teplá-Barrandian unit (TBU) of the Bohemian Massif was a part of the Avalonian-Cadomian belt at the northern margin of Gondwana during Neoproterozoic and Early Cambrian times. New detrital zircon ages and geochemical compositions of Late Neoproterozoic siliciclastic sediments confirm a deposition of the volcano-sedimentary successions of the TBU in a back-arc basin. A change in the geotectonic regime from convergence to transtension was completed by the time of the Precambrian-Cambrian boundary. The accumulation of around 2,500 m Lower Cambrian continental siliciclastics in a Basin-and-Range-type setting was accompanied by magmatism, which shows within-plate features in a few cases, but is predominantly derived from anatectic melts displaying the inherited island arc signature of their Cadomian source rocks. The geochemistry of clastic sediments suggests a deposition in a rift or strike-slip-related basin, respectively. A marine transgression during Middle Cambrian times indicates markedly thinned crust after the Cadomian orogeny. Upper Cambrian magmatism is represented by 1,500 m of subaerial andesites and rhyolites demonstrating several geochemical characteristics of an intra-plate setting. Zircons from a rhyolite give a U-Pb-SHRIMP age of 499±4 Ma. The Cambrian sedimentary and magmatic succession of the TBU records the beginning of an important rifting event at the northern margin of Gondwana.
相似文献
| Kerstin DrostEmail: |
16.
The irreversible water–rock mass exchanges leading to the production of the Fiume Grande valley (Calabria, Italy) stream waters
and groundwaters, starting from local rainwaters, were simulated through reaction path modeling in reaction progress (stoichiometric)
mode. The simulations assumed bulk dissolution of a phyllitic rock and calcite and precipitation of gibbsite, kaolinite, amorphous
silica, illite, a smectite solid mixture, a hydroxide solid mixture, and a trigonal carbonate solid mixture. The analytical
contents of major and trace elements in stream waters and groundwaters were satisfactorily reproduced. However, further investigations
are necessary to clarify the fate of As in this natural systems.
相似文献
| Rosanna De RosaEmail: |
17.
Spatial and temporal knowledge representation 总被引：1，自引：1，他引：0
Antony Galton 《Earth Science Informatics》2009,2(3):169-187
Knowledge Representation (KR) originated as a discipline within Artificial Intelligence, and is concerned with the representation
of knowledge in symbolic form so that it can be stored and manipulated on a computer. This article surveys that part of KR
that is concerned with the representation of space and time, with particular reference to the use of such representations
in geographical information science.
相似文献
| Antony GaltonEmail: |
18.
The regionalization of urban natural disasters in China 总被引：1，自引：1，他引：0
Jing-ai Wang Pei-jun Shi Xiang-sheng Yi Hui-cong Jia Lai-yin Zhu 《Natural Hazards》2008,44(2):169-179
An integrated urbanization level (CL) index and an integrated natural disaster intensity (QC) index were developed on the
basis of Disaster System Theory and China Natural Disaster Database for integrated urban disaster risk assessment. Integrated
quantitative assessments of the urban socio-economic system and the intensity of hazards in China were carried out by the
Model-Tupu (map series) and inter-feedback process using digital map technology. On the basis of this assessment, China can
be regionalized into three regions, namely, coastal urban disaster region, eastern urban disaster region and western urban
disaster region, 15 sub-regions and 22 units. These results can provide a scientific basis for determining a city’s disaster
risk management and natural disaster relief regionalization in China.
相似文献
| Pei-jun ShiEmail: |
19.
Sarah F. Ives 《GeoJournal》2009,74(3):245-255
Using a discussion of South African soap operas, I will place the idea of visuality in a discourse analysis that incorporates
a feminist epistemological lens, or an epistemology that integrates reflexivity and an acknowledgment of the dialogic nature
of visual media. Through this discussion, I will examine the possibilities that dialogism provides for unpacking and exploring
the politics of imperfect translation between the visual and the textual. These methodological interventions, I argue, will
help enrich discussions of the visual’s role in the contested realm of geographic imaginations and move beyond the distanced
position of the masculine gaze.
相似文献
| Sarah F. IvesEmail: |
20.
Ethnic coexistence in a pluralistic campus environment 总被引：1，自引：0，他引：1
Emile Kok-Kheng Yeoh 《GeoJournal》2006,66(3):223-241
In Malaysia, ethnic segregation seems to have grown more and more pronounced at all levels of education, which may have in
the main contributed to increasing occupational segregation by ethnicity when the graduates left to join the job market. Such
trends may be disturbing given the effort the country has put in to promote interethnic understanding and reduce interethnic
economic disparity since 1970. By critically investigating the dynamics of ethnic coexistence in the microcosm of the university
campus environment, this paper provides statistical evidence to show how far the country has progressed in terms of ethnic
relations since the watershed events of May 13, 1969; to what extent Malaysian multiethnic society is different now compared
to the unmistakable racial “corporateness” and interethnic “separateness” that Furnivall observed in his classic study of
1948; and in what ways ethnic relations have been reshaped by three decades of affirmative action policies and the form of
ethnic democracy adapted for this unique society.
相似文献
| Emile Kok-Kheng YeohEmail: |