The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Alberto Guadagnini - One of the best experts on this subject based on the ideXlab platform.
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Solute Concentration at a well in non gaussian aquifers under constant and time varying pumping schedule
Journal of Contaminant Hydrology, 2017Co-Authors: Arianna Libera, Felipe P J De Barros, Monica Riva, Alberto GuadagniniAbstract:Abstract Our study is keyed to the analysis of the interplay between engineering factors (i.e., transient pumping rates versus less realistic but commonly analyzed uniform extraction rates) and the heterogeneous structure of the aquifer (as expressed by the probability distribution characterizing transmissivity) on contaminant transport. We explore the joint influence of diverse ( a ) groundwater pumping schedules (constant and variable in time) and ( b ) representations of the stochastic heterogeneous transmissivity ( T ) field on temporal histories of Solute Concentrations observed at an extraction well. The stochastic nature of T is rendered by modeling its natural logarithm, Y = ln T , through a typical Gaussian representation and the recently introduced Generalized sub-Gaussian (GSG) model. The latter has the unique property to embed scale-dependent non-Gaussian features of the main statistics of Y and its (spatial) increments, which have been documented in a variety of studies. We rely on numerical Monte Carlo simulations and compute the temporal evolution at the well of low order moments of the Solute Concentration ( C ), as well as statistics of the peak Concentration ( C p ), identified as the environmental performance metric of interest in this study. We show that the pumping schedule strongly affects the pattern of the temporal evolution of the first two statistical moments of C , regardless the nature (Gaussian or non-Gaussian) of the underlying Y field, whereas the latter quantitatively influences their magnitude. Our results show that uncertainty associated with C and C p estimates is larger when operating under a transient extraction scheme than under the action of a uniform withdrawal schedule. The probability density function (PDF) of C p displays a long positive tail in the presence of time-varying pumping schedule. All these aspects are magnified in the presence of non-Gaussian Y fields. Additionally, the PDF of C p displays a bimodal shape for all types of pumping schemes analyzed, independent of the type of heterogeneity considered.
A V Kiryanov - One of the best experts on this subject based on the ideXlab platform.
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the use of erbium fiber laser relaxation frequency for sensing refractive index and Solute Concentration of aqueous solutions
Laser Physics Letters, 2008Co-Authors: H Arellanosotelo, Yuri O. Barmenkov, A V KiryanovAbstract:We report a novel-principle fiber-laser intra-cavity sensor for measuring refractive index and Solute Concentration of aqueous solutions. The sensor operation is based on a variation of the laser oscillation relaxation frequency (the measured parameter), sensitive to the intra-cavity loss change. The sensor capacity is demonstrated on the example of measurements of sugar Concentration in water. A modeling of the sensor operation is presented, allowing its performance optimization.
Xu Guang Huang - One of the best experts on this subject based on the ideXlab platform.
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fresnel reflection based fiber sensor for on line measurement of Solute Concentration in solutions
Sensors and Actuators B-chemical, 2007Co-Authors: Xu Guang HuangAbstract:Abstract A fiber sensor with a simple structure for measuring Solute Concentration in solutions is presented. The sensor uses only a diode laser as light source, three couplers, two sensing fiber ends with protective cladding, and two photodetectors. The measurement principle is based on relative Fresnel reflective intensity. Various Concentrations of salt solution and sugar solution are measured in the setup. The measured data are fitted to linear equation very well and the values of R2 are more than 0.995. Applying the relative technique, the errors resulted from fluctuation of light source and influences of environment are effectively eliminated, and the stability for long time measurement can be improved.
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a quasidistributed fiber optic sensor for Solute Concentration measurement based on fresnel reflection
Applied Physics Letters, 2007Co-Authors: Xu Guang HuangAbstract:A quasidistributed fiber sensor for Solute Concentration measurement based on Fresnel reflection from fiber tips and the interrogation of an arrayed waveguide grating is presented. Thin-film filters are utilized to achieve the possibility of wavelength-division-multiplexing distributed sensing. The experimental results can be fitted to a linear equation very well, with a value of R2 larger than 0.993. The quasidistributed sensor exhibits a capability for real-time, remote measurement of Concentrations with high precision, and offers a solid structure, low cost, and easy implementation.
Titus A Beu - One of the best experts on this subject based on the ideXlab platform.
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molecular dynamics simulations of ion transport through carbon nanotubes iii influence of the nanotube radius Solute Concentration and applied electric fields on the transport properties
Journal of Chemical Physics, 2011Co-Authors: Titus A BeuAbstract:The present investigations continue previous research on transport in aqueous ionic solutions through carbon nanotubes. Specifically, the effects of the nanotube radius, Solute Concentration, and applied external electric fields on the transport properties are investigated in terms of mobilities, currents, and pairing times of the Solute ions. The simulated transport features are corroborated with general theoretical results of nanofluidics (such as the linear log-log regime of the nanochannel conductance as function of the Solute Concentration and the current-voltage curve of the channel). Discontinuities in the partial ionic currents are explained on the basis of a recent theoretical model of quantized ionic conductance in nanopores, developed by Zwolak et al. Correlations between the structural and dynamic properties are established, linking causally the highly structured spatial density profiles, the ion pairing phenomenon and the ionic currents.
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molecular dynamics simulations of ion transport through carbon nanotubes ii structural effects of the nanotube radius Solute Concentration and applied electric fields
Journal of Chemical Physics, 2011Co-Authors: Titus A BeuAbstract:The reported work extends previously published research on transport in aqueous ionic solutions through carbon nanotubes. Specifically, the effects of the nanotube radius, Solute Concentration, and applied external electric fields on the solution structuring are investigated in terms of spatial density distributions, pair distribution functions, and electrostatic potential profiles. Several simulated structural features are consistent with general theoretical results of nanofluidics and can be interpreted fairly well with respect to these (such as the Donnan-type voltages established at the channel apertures depending on the logarithm of the maximum ion Concentration). The simulated properties are based on averages over the largest data collection times reported in the literature (0.8 μs), providing accurate estimates of the measured quantities.
H Arellanosotelo - One of the best experts on this subject based on the ideXlab platform.
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the use of erbium fiber laser relaxation frequency for sensing refractive index and Solute Concentration of aqueous solutions
Laser Physics Letters, 2008Co-Authors: H Arellanosotelo, Yuri O. Barmenkov, A V KiryanovAbstract:We report a novel-principle fiber-laser intra-cavity sensor for measuring refractive index and Solute Concentration of aqueous solutions. The sensor operation is based on a variation of the laser oscillation relaxation frequency (the measured parameter), sensitive to the intra-cavity loss change. The sensor capacity is demonstrated on the example of measurements of sugar Concentration in water. A modeling of the sensor operation is presented, allowing its performance optimization.