排序方式： 共有67条查询结果，搜索用时 15 毫秒
31.
This paper investigates the changes in Lisan Marl properties upon leaching the soluble minerals and collapse potential. Finite
element method was used to model dike construction and the relationships between soil parameters. To validate the chosen model
and obtain the required input data, one dimensional oedometer and drained direct shear tests were carried out. The models
were further validated by comparing the results with available published data. The results proved that the chosen model is
efficient in assessing the geotechnical behavior of the studied soil. 相似文献
32.
Randy L. Stotler Shaun K. Frape Humam Taha El Mugammar Craig Johnston Ian Judd-Henrey F. Edwin Harvey Robert Drimmie Jon Paul Jones 《Hydrogeology Journal》2011,19(1):101-115
The Waterloo Moraine is a stratigraphically complex system and is the major water supply to the cities of Kitchener and Waterloo in Ontario, Canada. Despite over 30?years of investigation, no attempt has been made to unify existing geochemical data into a single database. A composite view of the moraine geochemistry has been created using the available geochemical information, and a framework created for geochemical data synthesis of other similar flow systems. Regionally, fluid chemistry is highly heterogeneous, with large variations in both water type and total dissolved solids content. Locally, upper aquifer units are affected by nitrate and chloride from fertilizer and road salt. Typical upper-aquifer fluid chemistry is dominated by calcium, magnesium, and bicarbonate, a result of calcite and dolomite dissolution. Evidence also suggests that ion exchange and diffusion from tills and bedrock units accounts for some elevated sodium concentrations. Locally, hydraulic “windows??cross connect upper and lower aquifer units, which are typically separated by a clay till. Lower aquifer units are also affected by dedolomitization, mixing with bedrock water, and locally, upward diffusion of solutes from the bedrock aquifers. A map of areas where aquifer units are geochemically similar was constructed to highlight areas with potential hydraulic windows. 相似文献
33.
Majdi Al-Mahasneh Mohamad Al-Widyan Hussein Ababneh Taha Rababah Khalil Ereifej 《Natural Resources Research》2008,17(1):13-20
Grain dust is a by-product produced in large quantities from grain storage and milling facilities but as of yet is treated
as waste locally and regionally. Based on the conviction that material properties determination is a necessary first step
for the efficient handling, processing, and use of materials, this work was initiated with the purpose of characterizing grain
dust in terms of its physicochemical and thermal properties.
Grain dust as a special waste material is a complex, dry, grey powder, composed mainly of grain chips, soil, whole wheat and
barley seeds, and straw. The material was found to have a bulk density of 362 kg/m3, specific heat, thermal conductivity, and gross calorific value were 1540 J/kg K, 0.27 W/m K, and 4120 kJ/kg, respectively.
Nutritional composition showed low concentrations of protein, and ether extract, and high concentrations of carbohydrates,
ash, and crude fiber. Mineral analysis showed that Ca, Fe, and K were available in significant amounts ranging from 30 to
135 ppm.
The as-received material is dry enough to be stored very safely and burned for energy production in either its loose form
or as pellets. Moreover, adjustments to the ash content and C:N ratio of the material deems it a promising candidate as an
animal feed and as a substrate for composting and biogasification. 相似文献
34.
As the major water catchment in Hobart city, the River Derwent provides water services to Hobart residents; however, water quality of the River Derwent is becoming unreliable. The aims of this paper are to identify the major water issues in the river and to reveal its impacts on Hobart residents and ecosystem. A methodology of secondary data analysis has been involved; which covers a wide range of existing dissertations. Through all the analysis of data, heavy metals, contaminated sediment and overload nitrogen can be regarded as three main causes of the water pollution. Moreover, the impacts of the water pollution are proved to be significant and perennial. On the basis of the analysis result, water pollution tends to be a tough issue that requires a great amount of time and efforts to deal with. 相似文献
35.
We summarize an on-line coupled meteorological–emissions–photochemical modelling system that allows feedback from air-quality/chemistry
to meteorology via radiative forcing. We focus on the radiative-forcing impacts (direct effects) of ozone. We present an application
of the coupled modelling system to the episode of 23–31 July 1998 in Portland, Oregon, U.S.A. Results suggest that the inclusion
of radiative-forcing feedback produces small but accountable impacts. For this region and episode, stand-alone radiative transfer
simulations, i.e., evaluating the effects of radiative forcing independently of changes in meteorology or emissions, suggest
that a change of 1 ppb in ground-level ozone is approximately equivalent to a change of 0.017 W m−2 in radiative forcing. In on-line, coupled, three-dimensional simulations, where the meteorological dependencies are accounted
for, domain-wide peak ozone concentrations were higher by 2–4 ppb (relative to a simulated peak of 119.4 ppb) when including
the effects of radiative-forcing feedback. A scenario of 10% reduction in anthropogenic emissions produced slightly larger
decreases in ozone, an additional 1 ppb in local-peak reductions, relative to scenarios without feedback. 相似文献
36.
Haider Taha 《Boundary-Layer Meteorology》2008,127(2):193-218
We present an application of a fine-resolution, meso-urban meteorological model (urbanized MM5; uMM5) to a multi-day episode
in August 2000 in the Houston-Galveston Texas, USA region. The model’s episodic performance and its response to small changes
in land-cover and surface physical properties in the area, e.g., scenarios of urban heat island mitigation, are evaluated.
The model formulation is reviewed along with its parameterizations, data needs, and fine-resolution geometrical input. Development
of scenarios of increased urban albedo and vegetative cover is also discussed. This initial application of the uMM5 to the
Houston-Galveston region serves as a basis for future model improvements, evaluation of newer data and parameterization applications,
testing more aggressive surface modification scenarios, and performing fine-resolution photochemical modelling. It also provides
data for comparison of model results with those from previous studies of this region. 相似文献
37.
Multivariate homogeneity testing in a northern case study in the province of Quebec,Canada 总被引：1，自引：0，他引：1
Fateh Chebana Taha B. M. J. Ouarda Pierre Bruneau Marc Barbet Salaheddine El Adlouni Marco Latraverse 《水文研究》2009,23(12):1690-1700
In regional frequency analysis, the examination of the regional homogeneity represents an important step of the procedure. Flood events possess multivariate characteristics which can not be handled by classical univariate regional procedures. For instance, classical procedures do not allow to assess regional homogeneity while taking into consideration flood peak, volume and duration. Chebana and Ouarda proposed multivariate discordancy and homogeneity tests. They carried out a simulation study to evaluate the performance of these tests. In the present paper, practical aspects are investigated jointly on flood peak and flood volume of a data set from the Côte‐Nord region in the province of Quebec, Canada. It is shown that, after removing the discordant sites, the remaining ones constitute a homogeneous region for the volumes and heterogeneous region for the peaks. However, if both variables are jointly considered, the obtained region is possibly homogeneous. Furthermore, the results demonstrate the usefulness of the bivariate test to take into account the dependence structure between the variables representing the event, and to take advantage of more information from the hydrograph. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
38.
Taha Rabeh Jorge Miguel Miranda Joao Carvalho Andrei Bocin 《Geophysical Prospecting》2009,57(3):447-459
The study area is located in the Sinai Peninsula, which is considered one of the most promising regions for oil resources. Three different tectonic forces affect the area in the triple junction structures associated with the opening of the Gulf of Suez and the strike slip movement along the Gulf of Aqaba. The main goal of this work is to model the structure of the basement rocks in the study area using magnetic methods. To achieve this, a high-resolution land magnetic survey was acquired and the results were combined with existing seismic reflection data. The magnetic interpretation was carried out using the analytical signal, horizontal gradient, Euler and Werner deconvolution and 3D magnetic modelling methods. We concluded that most of the deduced structures are trending in N–S, N35°–N45° west and E–W directions. The Aqaba trend (N15°–N25° east) is barely noticeable. The depth to the basement rocks ranges from 1 km to more than 2 km below sea level and these results are in agreement with the available well log data. In addition, interpretation of seismic reflection sections was carried out and compared with overlapping magnetic profiles interpreted using Euler deconvolution. They show that the sedimentary section was affected by the basement tectonics, with faults extending from the basement upwards through the sedimentary cover. These faults constitute good potential structural traps for oil accumulation. 相似文献
39.
Anik Daigle Andr St-Hilaire Valrie Ouellet Julie Corriveau Taha B.M.J. Ouarda Laurent Bilodeau 《Journal of Hydrology》2009,370(1-4):29-38
A data-driven model is designed using artificial neural networks (ANN) to predict the average onset for the annual water temperature cycle of North-American streams. The data base is composed of daily water temperature time series recorded at 48 hydrometric stations in Québec (Canada) and northern US, as well as the geographic and physiographic variables extracted from the 48 associated drainage basins. The impact of individual and combined drainage area characteristics on the stream annual temperature cycle starting date is investigated by testing different combinations of input variables. The best model allows to predict the average temperature onset for a site, given its geographical coordinates and vegetation and lake coverage characteristics, with a root mean square error (RMSE) of 5.6 days. The best ANN model was compared favourably with parametric approaches. 相似文献
40.
Summary This paper summarizes results from a mesoscale modeling study to quantify the possible meteorological and energy-use impacts
of large-scale increases in surface albedo and vegetative fraction. Ten regions in the U.S. were characterized and simulated
in base- and modified-surface conditions. Time- and space-dependent meteorological variables were simulated for each region
in four 3-day episodes to represent a range of seasonal variations.
Using a simple interpolative procedure, a complete year of hourly weather data was created for each region (based on episodic
meteorological simulation results) and input into energy-use models. The modified weather input was used to assess the effects
of large-scale albedo and vegetative fraction changes on annual energy consumption in each of the ten areas targeted in this
study. The simulations suggest annual electricity savings of between 1and 6.7 kWh m−2 (of roof area) in residential neighborhoods and between 2 and 6.1 kWh m−2 in office areas, depending on region. Annual gas penalties amount to up to 34.8 MJ m−2 (of roof area) in residential neighborhoods and up to 21.1 MJ m−2 in office areas.
Received December 1, 1996 Revised May 11, 1998 相似文献