Geochemical Prospectivity Mapping Through a Feature Extraction–Selection Classification Scheme     

Zekri  Hamid  Cohen  David R.  Mokhtari  Ahmad Reza  Esmaeili  Abbas 《Natural Resources Research》2019,28(3):849-865

Natural Resources Research - Machine learning (ML) schemes can enhance success in geochemical prospectivity mapping. This study has examined the effectiveness of several feature extraction or...  相似文献   

Improved spatial delineation of streambed properties and water fluxes using distributed temperature sensing          下载免费PDF全文

Landon J. S. Halloran  Hamid Roshan  Gabriel C. Rau  Martin S. Andersen  R. Ian Acworth 《水文研究》2016,30(15):2686-2702

A new method was developed for analysing and delineating streambed water fluxes, flow conditions and hydraulic properties using coiled fibre‐optic distributed temperature sensing or closely spaced discrete temperature sensors. This method allows for a thorough treatment of the spatial information embedded in temperature data by creating a matrix visualization of all possible sensor pairs. Application of the method to a 5‐day field dataset reveals the complexity of shallow streambed thermal regimes. To understand how velocity estimates are affected by violations of assumptions of one‐dimensional, saturated, homogeneous flow and to aid in the interpretation of field observations, the method was also applied to temperature data generated by numerical models of common field conditions: horizontal layering, presence of lateral flow and variable streambed saturation. The results show that each condition creates a distinct signature visible in the triangular matrices. The matrices are used to perform a comparison of the behaviour of one‐dimensional analytical heat‐tracing models. The results show that the amplitude ratio‐based method of velocity calculation leads to the most reliable estimates. The minimum sensor spacing required to obtain reliable velocity estimates with discrete sensors is also investigated using field data. The developed method will aid future heat‐tracing studies by providing a technique for visualizing and comparing results from fibre‐optic distributed temperature sensing installations and testing the robustness of analytical heat‐tracing models. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Assessing the impact of CMIP5 climate multi-modeling on estimating the precipitation seasonality and timing     

Mehmet C. Demirel  Hamid Moradkhani 《Climatic change》2016,135(2):357-372

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Ionic conductivity in gem-quality single-crystal alkali feldspar from the Eifel: temperature,orientation and composition dependence     

Hamid El Maanaoui  Fabian Wilangowski  Aditya Maheshwari  Hans-Dieter Wiemhöfer  Rainer Abart  Nicolaas A. Stolwijk 《Physics and Chemistry of Minerals》2016,43(5):327-340

We measured the ion conductivity of single-crystal alkali feldspar originating from two different locations in the Eifel/Germany, named Volkesfeld and Rockeskyller sanidine and having potassium site fractions \(C_\mathrm{K}\) of 0.83 and 0.71, respectively. The dc conductivities resulting from electrochemical impedance spectroscopy over the temperature range of 300–900 \(^{\circ }\hbox {C}\) show a weak composition dependence but pronounced differences between the b-direction [\(\perp (010)\)] and \(c^{*}\)-direction [\(\perp (001)\)] of the monoclinic feldspar structure. Conductivity activation energies obtained from the observed linear Arrhenius plots are close to 1.2 eV in all cases, which is closely similar to the activation energies of the \(^{22}\mathrm{Na}\) tracer diffusivity in the same crystals. Taking into account literature data on K tracer diffusion and diffusion correlation effects, the present results point to a predominance of the interstitialcy mechanism over the vacancy mechanism in mass and charge transport on the alkali sublattice in potassium-rich alkali feldspar.  相似文献   

Spatial,temporal and frequency based climate change assessment in Columbia River Basin using multi downscaled-scenarios   总被引：1，自引：0，他引：1  

Arun Rana  Hamid Moradkhani 《Climate Dynamics》2016,47(1-2):579-600

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Classification of Polarimetric SAR Data Based on Object-Based Multiple Classifiers for Urban Land-Cover   总被引：1，自引：0，他引：1  

Masoud Habibi  Mahmod Reza Sahebi  Yasser Maghsoudi  Shaheen Ghayourmanesh 《Journal of the Indian Society of Remote Sensing》2016,44(6):855-863

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Fast ultrahigh-degree global spherical harmonic synthesis on nonequispaced grid points at irregular surfaces     

Siamak Moazezi  Hossein Zomorrodian  Hamid Reza Siahkoohi  Alireza Azmoudeh-Ardalan  Ali Gholami 《Journal of Geodesy》2016,90(9):853-870

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Experimental Evaluation of Construction Waste and Ground Granulated Blast Furnace Slag as Alternative Soil Stabilisers     

Umair Hasan  Amin Chegenizadeh  Mochamad Arief Budihardjo  Hamid Nikraz 《Geotechnical and Geological Engineering》2016,34(6):1707-1722

In this study, the effect of ground granulated blast furnace slag (GGBFS) and recycled construction waste (CW) on bentonite clay stabilisation were investigated. The unconfined compressive strength (UCS) of specimens was evaluated with different combinations of GGBFS and CW over various curing periods. A series of micro analysis tests consisting of scanning electron microscope, energy dispersive spectrometer and X-ray diffraction were also conducted to determine the microstructural arrangement and mineralogical effect of the stabilisation treatment. The UCS results showed an increment in strength after introduction of GGBFS and CW and the longer curing period produced more pronounced results. The optimum additive ratio was calculated as 5 % of slag and 20 % of construction waste under all curing conditions. The micro analytical results also indicated formation of structural bonds between admixtures and bentonite in stabilised specimens, as slag crystals and bentonite particles were observed to occupy the cavities and vesicles on the construction waste grains. However, the experimental data shows that the strength improvement is not significant with the addition of only construction waste.  相似文献   

Steady critical discharge rates from vertical and horizontal wells in fresh–saline aquifers with sharp interfaces     

Raziyeh Hendizadeh  Mazda Kompanizare  Mohammad R. Hashemi  G. Reza Rakhshandehroo 《Hydrogeology Journal》2016,24(4):865-876

In this study, the critical (or maximum) discharge rates before saline water enters a well were determined for vertical and horizontal wells in a freshwater aquifer which is separated from a static saline aquifer by a sharp interface. Flow around the well was solved by integration of a point sink solution along the well axis, and both the critical discharge rate and critical interface rise were determined through a comparison of the heads and vertical gradients at the saline–fresh water interface. The rates were determined for vertical and horizontal wells with various lengths and depths for different aquifer salinities. Results were generalized by drawing dimensionless type curves. The results showed that the dimensionless total critical discharge rates are higher for the longer horizontal wells and longer vertical wells with a certain bottom depth, and they almost linearly decrease with well depth at rates of 0.7–0.9. For the dimensionless well length of 0.2, the dimensionless total discharge rate of a horizontal well is about 0.1 more than that of a vertical well with the same length and well-top depth. Also, the critical discharge rates per unit length of well are inversely proportional to well length and remarkably higher for shallower wells. Additionally, the critical pumping rate is proportional to the salinity difference of the aquifers. These results were confirmed by comparison to existing solutions for vertical wells with dimensionless lengths of 0.2, 0.5 and 0.6, and for critical interface rises in the range of 0.75–0.9.  相似文献   

Improved regional groundwater flow modeling using drainage features: a case study of the central northern karst aquifer system of Puerto Rico (USA)     

Reza Ghasemizadeh  Xue Yu  Christoph Butscher  Ingrid Y. Padilla  Akram Alshawabkeh 《Hydrogeology Journal》2016,24(6):1463-1478

In northern Puerto Rico (USA), subsurface conduit networks with unknown characteristics, and surface features such as springs, rivers, lagoons and wetlands, drain the coastal karst aquifers. In this study, drain lines connecting sinkholes and springs are used to improve the developed regional model by simulating the drainage effects of conduit networks. Implemented in an equivalent porous media (EPM) approach, the model with drains is able to roughly reproduce the spring discharge hydrographs in response to rainfall. Hydraulic conductivities are found to be scale dependent and significantly increase with higher test radius, indicating scale dependency of the EPM approach. Similar to other karst regions in the world, hydraulic gradients are steeper where the transmissivity is lower approaching the coastline. This study enhances current understanding of the complex flow patterns in karst aquifers and suggests that using a drainage feature improves modeling results where available data on conduit characteristics are minimal.  相似文献