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431.
Acta Geotechnica - The shear modulus of a soil, G, shows a hyperbolic degradation curve relationship with increasing shear strain, γ. G is usually normalized against the small-strain modulus... 相似文献
432.
433.
Kaushik Roy Prasanta Chatterjee S. S. Kausik C. S. Wong 《Astrophysics and Space Science》2014,350(2):599-605
The dust-acoustic shock waves have been theoretically investigated using reductive perturbation technique. An unmagnetized four-component dusty plasma system consisting of nonextensive q-distributed electrons, Boltzmann distributed ions, and negatively as well as positively charged dust particles has been considered. The solution of Burgers equation in planar geometry is numerically analyzed. It has been observed that the nonextensive q-distribution of electrons has a significant role in the formation of shock waves. The relevance of our results to astrophysics as well as laboratory plasmas are briefly discussed. 相似文献
434.
Applying Quantitative Molecular Tools for Virus Transport Studies: Opportunities and Challenges
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Bacteriophages have been used in soil column studies for the last several decades as surrogates to study the fate and transport behavior of enteric viruses in groundwater. However, recent studies have shown that the transport behavior of bacteriophages and enteric viruses in porous media can be very different. The next generation of virus transport science must therefore provide more data on mobility of enteric viruses and the relationship between transport behaviors of enteric viruses and bacteriophages. To achieve this new paradigm, labor intensity devoted to enteric virus quantification method must be reduced. Recent studies applied quantitative polymerase chain reaction (qPCR) to column filtration experiments to study the transport behavior of human adenovirus (HAdV) in porous media under a variety of conditions. A similar approach can be used to study the transport of other enteric viruses such as norovirus. Analyzing the column samples with both qPCR and culture assays and applying multiplex qPCR to study cotransport behavior of more than one virus will provide information to under‐explored areas in virus transport science. Both nucleic acid extraction kits and one‐step lysis protocols have been used in these column studies to extract viral nucleic acid for qPCR quantification. The pros and cons of both methods are compared herein and solutions for overcoming problems are suggested. As better understanding of the transport behavior of enteric viruses is clearly needed, we strongly advocate for application of rapid molecular tools in future studies as well as optimization of protocols to overcome their current limitations. 相似文献
435.
Ho Hung Chak Wai Ka Ming He Minhao Chan Ta-Chien Deng Chengbin Wong Man Sing 《Natural Hazards》2020,103(1):623-637
Natural Hazards - In this study, we applied the Weather Research and Forecasting model to project 2050 urban and rural temperature. We applied a time-stratified analysis to compare it with... 相似文献
436.
Vanessa N.L. Wong Scott G. Johnston Richard T. Bush Leigh A. Sullivan Christina Clay Edward D. Burton Peter G. Slavich 《Estuarine, Coastal and Shelf Science》2010
A major fish kill occurred in the Richmond River estuary in January 2008 due to oxygen depletion following extensive overbank flooding. This paper examines spatial and temporal changes in the chemistry of main channel waters, thereby identifying the primary sources of deoxygenating water. Over 40 km of the mid- to lower estuary main channel was deoxygenated within seven days of the flood peak. Hypoxia was confined to downstream of the confluences with mid-estuary backswamp basins and occurred during the later phase of the flood recession. Water chemistry at key locations in the estuary indicated elevated concentrations of redox sensitive species associated with acid sulfate soils (ASS) during the hypoxic period. Peak concentrations of Fe2+ up to 18.2 μmol L−1, dissolved Mn up to 4.3 μmol L−1, chemical oxygen demand (COD) up to 2052 μmol L−1, dissolved organic carbon (DOC) up to 960 μmol L−1 and elemental S0 up to 4.7 μmol L−1 were found in the backswamp discharge confluences and mid-estuary main channel locations. The geochemical signature of main channel floodwaters identifies anaerobic decomposition of floodplain vegetation in ASS backswamps as a primary process leading to generation of hypoxic waters. The transport of these hypoxic floodwaters to the estuary has been accelerated and prolonged by extensive floodplain drainage, thereby enhancing the magnitude and duration of estuarine deoxygenation. 相似文献
437.
Bart Eklund Carly Ricondo Helen Artz-Patton Jessica Milose Chi-Wah Wong 《Ground Water Monitoring & Remediation》2023,43(1):35-43
An investigation at a major industrial facility in the Midwestern United States provides insights regarding the amount of attenuation of sub-surface vapors occurring at industrial buildings. The buildings at the facility were ranked in terms of vapor intrusion potential and testing began in October 2016 and is ongoing. Results have been evaluated for data collected at 718 unique locations across 77 buildings. A total of 1646 sample pairs (sub-slab and indoor air) have been collected and analyzed for 65 analytes, resulting in a total of 106,990 data pairs. As many as 49 sample pairs were collected within a given building during a single sampling event and up to 11 rounds of seasonal testing have been performed at selected buildings. Seasonal variability in sub-slab soil-gas concentrations was found to be negligible. Data analysis was performed to look for data trends across the entire data set and identify inter-building comparisons. This data evaluation focused on individual volatile organic compounds (e.g., tetrachloroethylene, trichloroethylene) present in the sub-slab soil gas at concentrations exceeding 1000 μg/m3. A total of 157 building-specific attenuation coefficients (α) were evaluated. This evaluation demonstrated that large industrial buildings have a much greater attenuation than that assumed for single-family residential buildings. All attenuation coefficient values were lower than 0.03, which is the standard regulatory default for non-residential buildings. The median value was 9.3E-05 and the 95% upper confidence limit was 2.7E-04. There is some evidence of lower attenuation under wintertime conditions. The data suggests that the default attenuation factor of 0.03 over-predicts indoor air impacts at this industrial facility by at least two orders of magnitude. 相似文献
438.
Changing population density is often ignored in studies of population growth and population transfer in the United States. We show that there is a complex relationship between patterns of population growth and density increase by state. The largest gains in density are in the states of the northeastern megalopolis, California, and Florida. Analysis of the 150 counties with the greatest increases in density between 1980 and 1990 shows that they are well distributed across the United States including the larger metropolitan areas of the “Rustbelt.” In general, the most densely populated states and places are becoming more densely populated, a concept we refer to as densification. 相似文献
439.
Summary A completely new nonhydrostatic model system known as the Advanced Regional Prediction System (ARPS) has been developed in
recent years at the Center for Analysis and Prediction of Storms (CAPS) at the University of Oklahoma. The ARPS is designed
from the beginning to serve as an effective tool for basic and applied research and as a system suitable for explicit prediction
of convective storms as well as weather systems at other scales. The ARPS includes its own data ingest, quality control and
objective analysis packages, a data assimilation system which includes single-Doppler velocity and thermodynamic retrieval
algorithms, the forward prediction component, and a self-contained post-processing, diagnostic and verification package.
The forward prediction component of the ARPS is a three-dimensional, nonhydrostatic compressible model formulated in generalized
terrain-following coordinates. Minimum approximations are made to the original governing equations. The split-explicit scheme
is used to integrate the sound-wave containing equations, which allows the horizontal domain-decomposition strategy to be
efficiently implemented for distributed-memory massively parallel computers. The model performs equally well on conventional
shared-memory scalar and vector processors. The model employs advanced numerical techniques, including monotonic advection
schemes for scalar transport and variance-conserving fourth-order advection for other variables. The model also includes state-of-the-art
physics parameterization schemes that are important for explicit prediction of convective storms as well as the prediction
of flows at larger scales.
Unique to this system are the consistent code styling maintained for the entire model system and thorough internal documentation.
Modern software engineering practices are employed to ensure that the system is modular, extensible and easy to use.
The system has been undergoing real-time prediction tests at the synoptic through storm scales in the past several years over
the continental United States as well as in part of Asia, some of which included retrieved Doppler radar data and hydrometeor
types in the initial condition.
As the first of a two-part paper series, we describe herein the dynamic and numerical framework of the model, together with
the subgrid-scale turbulence and the PBL parameterization. The model dynamic and numerical framework is then verified using
idealized and realistic mountain flow cases and an idealized density current. Other physics parameterization schemes will
be described in Part II, which is followed by verification against observational data of the coupled soil-vegetation model,
surface layer fluxes and the PBL parameterization. Applications of the model to the simulation of an observed supercell storm
and to the prediction of a real case are also found in Part II. In the latter case, a long-lasting squall line developed and
propagated across the eastern part of the United States following a historical number of tornado outbreak in the state of
Arkansas.
Received April 14, 2000 Revised July 17, 2000 相似文献
440.
George T.F. Wong 《Marine Chemistry》1980,9(1):1-12
With minor modifications, the oxidation state diagram may be used to study the redox chemistry of elements in marine waters. In addition to indicating the most stable oxidation state of an element, the diagram also shows the possible existence of metastable species. Oxidation state diagrams of the nitrogen and the manganese systems are presented. The inferences drawn from these diagrams are consistent with our present understanding of the marine geochemistry of these elements. 相似文献