Analytical solutions for the capture zone of a pumping well near a stream

The capture zone for a fully penetrating well in an aquifer with regional flow to a stream boundary under steady-state conditions was delineated using complex algebra and image well theory. Regional flow in the aquifer was allowed to take different directions relative to the stream axis. Two critical pumping rates, Q _C1 and Q _C2, produce three capture-zone pattern scenarios: (1) at low pumping rates (Q?<?Q _C1) water is solely withdrawn from the aquifer and no water from the stream enters the aquifer, (2) at medium pumping rates (Q _C1?<?Q?<?Q _C2) a portion of stream water enters the aquifer but it is not captured by the well, and (3) at high pumping rates (Q?>?Q _C2) pumped water is supplied from both the aquifer and the stream with different proportions. For the second and third scenarios, the stream length interval through which stream water enters the aquifer was determined and found to be more sensitive to pumping rate as the regional flow direction approaches the stream axis. The portion of pumped water supplied by the stream was determined in the third scenario. Finally, the capture-zone asymmetry with respect to its axial line was delineated.     

Interrelationship of TOC,As, Fe,Mn, Al and Si in shallow alluvial aquifers in Chapai-Nawabganj,Northwestern Bangladesh: implication for potential source of organic carbon

Two boreholes and ten piezometers in the Ganges flood plain were drilled and installed for collecting As-rich sediments and groundwater. Groundwater samples from the Ganges flood plain were collected for the analysis of cations (Ca²⁺, Mg²⁺, K⁺, Na⁺), anions (Cl⁻, NO₃ ⁻, SO₄ ²⁻), total organic carbon (TOC), and trace elements (As, Mn, Fe, Sr, Se, Ni, Co, Cu, Mo, Sb, Pb). X-ray powder diffraction was performed to characterize the major mineral contents of aquifer sediments and X-ray fluorescence (XRF) to analyze the major chemical composition of alluvial sediments. Results of XRF analysis clearly show that fine-grained sediments contain higher amounts of trace element because of their high surface area for adsorption. Relative fluorescence index (15–38 QSU) of humic substance in groundwater was measured using spectrofluorometer, the results revealed that groundwater in the Ganges flood plain contains less organic matter (OM). Arsenic concentration in water ranges from 2.8 to 170 μg/L (mean 50 μg/L) in the Ganges flood plain. Arsenic content in sediments ranges from 2.1 to 14 mg/kg (mean 4.58 mg/kg) in the flood plains. TOC ranges from 0.49 to 3.53 g/kg (mean 1.64 g/kg) in the Ganges flood plain. Arsenic is positively correlated with TOC (R ² = 0.55) in sediments of this plain. Humic substances were extracted from the sediments from the Ganges flood plain. Fourier transform infrared analysis of the sediments revealed that the plain contains less humic substances. The source of organic carbon was assigned from δ¹³C values obtained using elemental analysis-isotope ratio mass spectrometry (EA-IRMS); the values (−10 to −29.44‰) strongly support the hypothesis that the OM of the Ganges flood plain is of terrestrial origin.     

Application of the spectral decomposition technique for characterizing reservoir extensional system in the Abadan Plain, southwestern Iran

The Abadan plain in southwestern Iran has important petroleum reservoir potential but poorly defined structural setting. It is located at the Mesopotamian foredeep basin, bounded by the Arabian plate and the Dezful Embayment. The main reservoir in this field is the Fahliyan formation, composed of reef carbonates. Most of the Abadan area is flat and covered by recent alluvial deposits with no outcrops. Studies of the structures in this area have provided information about the structural history and allowed better reservoir and drilling management. Seismic spectral decomposition techniques have been utilized as a quick and effective interpretation tool. Fast Fourier transform (FFT) and continuous wavelet transforms (CWT) have been used to convert time to frequency domain, and have been applied to detect fault systems in the reservoir. Application of the Fast Fourier transform (FFT) and continuous wavelet transforms (CWT) indicate that the Abadan reservoir consists normal extensional system of the reservoir which display paralleling of contour common depth in two sides of extensional system in some regions and large displacement between two sides of contours indicate that system is normal in which hanging wall moved over footwall. Various displacements between sides indicate parallel strike-slip movements which are associated with reverse faulting and inversion tectonics.     

Comparison of IWG and SDSM weather generators for climate change impact assessment

Theoretical and Applied Climatology - Weather generators (WGs) typically have unique advantages to the climate change impacts assessment. However, each of them has the weaknesses, strengths, and...     

Time evolution of nonplanar electron acoustic shock waves in a plasma with superthermal electrons

The propagation of cylindrical and spherical electron acoustic (EA) shock waves in unmagnetized plasmas consisting of cold fluid electrons, hot electrons obeying a superthermal distribution and stationary ions, has been investigated. The standard reductive perturbation method (RPM) has been employed to derive the cylindrical/spherical Korteweg-de-Vries-Burger (KdVB) equation which governs the dynamics of the EA shock structures. The effects of nonplanar geometry, plasma kinematic viscosity and electron suprathermality on the temporal evolution of the cylindrical and spherical EA shock waves are numerically examined.     

Effect of q-nonextensive distribution of electrons on dust-ion acoustic solitons

Properties of dust-ion acoustic solitary waves (DIASWs) in dusty plasmas composed of nonextensive electrons, cold fluid ions and stationary dust particles are investigated. The possibility of soliton formation and the effect of nonextensivity of the electron distribution on the soliton characters are studied using the pseudo-potential method. Regions of parameters in which a solitary wave can be propagated in the plasma is analyzed too. It is found that the solitary excitations strongly depend on the electron-ion density ratio (μ), Mach numbers (M) as well as the nonextensive parameter (q). It is shown that the domain of allowed Mach numbers depends drastically on the plasma parameters and especially on the electron nonextensivity. It is found that beyond a threshold value of the nonextensive parameter (q), dust-ion acoustic solitons are admitted.     

Introducing a Novel Approach for Oil-Oil Correlation based on Asphaltene Structure:X-ray Diffraction

Asphaltenes have always been an attractive subject for researchers. However, the application of this fraction of the geochemical field has only been studied in a limited way. In other words, despite many studies on asphaltene structure, the application of asphaltene structures in organic geochemistry has not so far been assessed. Oil-oil correlation is a well-known concept in geochemical studies and plays a vital role in basin modeling and the reconstruction of the burial history of basin sediments, as well as accurate characterization of the relevant petroleum system. This study aims to propose the X-ray diffraction (XRD) technique as a novel method for oil-oil correlation and investigate its reliability and accuracy for different crude oils. To this end, 13 crude oil samples from the Iranian sector of the Persian Gulf region, which had previously been correlated by traditional geochemical tools such as biomarker ratios and isotope values, in four distinct genetic groups, were selected and their asphaltene fractions analyzed by two prevalent methods of XRD and Fourier-transform infrared spectroscopy (FTIR). For oil-oil correlation assessment, various cross-plots, as well as principal component analysis (PCA), were conducted, based on the structural parameters of the studied asphaltenes. The results indicate that asphaltene structural parameters can also be used for oil-oil correlation purposes, their results being completely in accord with the previous classifications. The average values of distance between saturated portions (dr) and the distance between two aromatic layers (dm) of asphaltene molecules belonging to the studied oil samples are 4.69? and 3.54?, respectively. Furthermore, the average diameter of the aromatic sheets (La), the height of the clusters (Lc), the number of carbons per aromatic unit (Cau), the number of aromatic rings per layer (Ra), the number of sheets in the cluster (Me) and aromaticity (fa) values of these asphaltene samples are 10.09?, 34.04?, 17.42?, 3.78?, 10.61? and 0.26?, respectively. The results of XRD parameters indicate that plots of dr vs. dm, dr vs. Me, dr vs. fa, dm vs. Lc, Lc vs. La, and fa vs. La perform appropriately for distinguishing genetic groups. A comparison between XRD and FTIR results indicated that the XRD method is more accurate for this purpose. In addition, decision tree classification, one of the most efficacious approaches of machine learning, was employed for the geochemical groups of this study for the first time. This tree, which was constructed using XRD data, can distinguish genetic groups accurately and can also determine the characteristics of each geochemical group. In conclusion, the obtaining of structural parameters for asphaltene by the XRD technique is a novel, precise and inexpensive method, which can be deployed as a new approach for oil-oil correlation goals. The findings of this study can help in the prompt determination of genetic groups as a screening method and can also be useful for assessing oil samples affected by secondary processes.     

Consistency of seven different GNSS global ionospheric mapping techniques during one solar cycle

In the context of the International GNSS Service (IGS), several IGS Ionosphere Associated Analysis Centers have developed different techniques to provide global ionospheric maps (GIMs) of vertical total electron content (VTEC) since 1998. In this paper we present a comparison of the performances of all the GIMs created in the frame of IGS. Indeed we compare the classical ones (for the ionospheric analysis centers CODE, ESA/ESOC, JPL and UPC) with the new ones (NRCAN, CAS, WHU). To assess the quality of them in fair and completely independent ways, two assessment methods are used: a direct comparison to altimeter data (VTEC-altimeter) and to the difference of slant total electron content (STEC) observed in independent ground reference stations (dSTEC-GPS). The main conclusion of this study, performed during one solar cycle, is the consistency of the results between so many different GIM techniques and implementations.     

A new rating system approach for risk analysis of rock slopes

In this paper, an approach is presented to analyze the stability risk of rock slopes based on a new rating system. Three factors are used to estimate the risk level of rock slopes: (1) failure probability, (2) element at risk rating, and (3) vulnerability rating. Element at risk and vulnerability ratings are both given a range from 0 to 10, and the probability of failure is varied between 0 and 1, so the risk rating ranges between 0 and 100. This risk rating can be used to determine both the quantitative and qualitative risk levels of slopes at the same time. The method is tested on the western sector of the slopes facing Songun copper plant phase III, Iran, to clarify its procedures and assess its validity. Deterministic kinematic analyses showed that the slope has a potential for circular failure. Risk assessments revealed that the risk levels of the slope in both static and pseudo-static conditions are “very low” and “high,” respectively.     

Assessment of the hurricane-induced power outages from a demographic,socioeconomic, and transportation perspective

Natural disasters have devastating effects on the infrastructure and disrupt every aspect of daily life in the regions they hit. To alleviate problems caused by these disasters, first an impact assessment is needed. As such, this paper focuses on a two-step methodology to identify the impact of Hurricane Hermine on the City of Tallahassee, the capital of Florida. The regional and socioeconomic variations in the Hermine’s impact were studied via spatially and statistically analyzing power outages. First step includes a spatial analysis to illustrate the magnitude of customers affected by power outages together with a clustering analysis. This step aims to determine whether the customers affected from outages are clustered or not. Second step involves a Bayesian spatial autoregressive model in order to identify the effects of several demographic-, socioeconomic-, and transportation-related variables on the magnitude of customers affected by power outages. Results showed that customers affected by outages are spatially clustered at particular regions rather than being dispersed. This indicates the need to pinpoint such vulnerable locations and develop strategies to reduce hurricane-induced disruptions. Furthermore, the increase in the magnitude of affected customers was found to be associated with several variables such as the power network and total generated trips as well as the demographic factors. The information gained from the findings of this study can assist emergency officials in identifying critical and/or less resilient regions, and determining those demographic and socioeconomic groups which were relatively more affected by the consequences of hurricanes than others.