Planar Gardner solitons and double layers in dusty electronegative plasmas with kappa distributed electrons

A theoretical investigation has been made on the Dust ion-acoustic (DIA) Gardner solitons (GSs) and double layers (DLs) in electronegative plasma consisting of inertial positive and negative ions, super-thermal (kappa distributed) electrons, and negatively charged static dust. The standard reductive perturbation method is employed to derive the Korteweg-de Vries (K-dV), modified K-dV (mK-dV), and standard Gardner equations, which admits solitary waves (SWs) and DLs solutions. It have been found that GSs and DLs exist for α around its critical value α _c , where α _c is the value of α corresponding to the vanishing of the nonlinear coefficient of the K-dV equation. The parametric regimes for the existence of both the positive as well as negative SWs and negative DLs are obtained. The basic features of DIA SWs and DLs are analyzed and it has been found that the polarity, speed, height, thickness of such DIA SWs and DLs structures, are significantly modified due to the presence of two types of ions and spectral index (κ) of super-thermal electrons. It has also been found that the characteristics of DIA GSs and DLs, are different from that of the K-dV solitons and mK-dV solitons. The relevance of our results to different interstellar space plasma situations are discussed.     

Integrating basin modeling with seismic technology and rock physics

We explore the link between basin modelling and seismic inversion by applying different rock physics models. This study uses the E‐Dragon II data in the Gulf of Mexico. To investigate the impact of different rock physics models on the link between basin modelling and seismic inversion, we first model relationships between seismic velocities and both (1) porosity and (2) effective stress for well‐log data using published rock physics models. Then, we build 1D basin models to predict seismic velocities derived from basin modelling with different rock physics models, in a comparison with average sonic velocities measured in the wells. Finally, we examine how basin modelling outputs can be used to aid seismic inversion by providing constraints for the background low‐frequency model. For this, we run different scenarios of inverting near angle partial stack seismic data into elastic impedances to test the impact of the background model on the quality of the inversion results. The results of the study suggest that the link between basin modelling and seismic technology is a two‐way interaction in terms of potential applications, and the key to refine it is establishing a rock physics models that properly describes changes in seismic signatures reflecting changes in rock properties.     

The Fill–Spill Hydrology of Prairie Wetland Complexes during Drought and Deluge

The fill–spill of surface depressions (wetlands) results in intermittent surface water connectivity between wetlands in the prairie wetland region of North America. Dynamic connectivity between wetlands results in dynamic contributing areas for runoff. However, the effect of fill–spill and the resultant variable or dynamic basin contributing area has largely been disregarded in the hydrological community. Long‐term field observations recorded at the St. Denis National Wildlife Area, Saskatchewan, allow fill–spill in the basin to be identified and quantified. Along with historical water‐level observations dating back to 1968, recent data collected for the basin include snow surveys, surface water survey and production of a light detection and ranging–derived digital elevation model. Data collection for the basin includes both wet and dry antecedent basin conditions during spring runoff events. A surface water survey at St. Denis in 2006 reveals a disconnected channel network during the spring freshet runoff event. Rather than 100% of the basin contributing runoff to the outlet, which most hydrological models assume, only approximately 39% of the basin contributes to the outlet. Anthropogenic features, such as culverts and roads, were found to influence the extent and spatial distribution of contributing areas in the basin. Historical pond depth records illustrate the effect of antecedent basin conditions on fill–spill and basin contributing area. A large pond at the outlet of the St. Denis basin, which only receives local runoff during dry years when upstream surface storage has not been satisfied, has pond runoff volumes that increase by a factor of 20 or more during wet years when upstream antecedent basin surface storage is satisfied and basin‐wide runoff contributes to the pond. Copyright © 2011 John Wiley & Sons, Ltd.     

Source parameters of March 10 and September 13, 2007, United Arab Emirates earthquakes

On March 10 and September 13, 2007 two earthquakes with moment magnitudes 3.66 and 3.94, respectively, occurred in the eastern part of the United Arab Emirates (UAE). The two events were widely felt in the northern Emirates and Oman and were accompanied by a few aftershocks. Ground motions from these events were well recorded by the broadband stations of Dubai (UAE) and Oman seismological networks and provide an excellent opportunity to study the tectonic process and present day stress field acting in this area. In this study, we report the focal mechanisms of the two main shocks by two methods: first motion polarities and regional waveform moment tensor inversion. Our results indicate nearly pure normal faulting mechanisms with a slight strike slip component. We associated the fault plane trending NNE–SSW with a suggested fault along the extension of the faults bounded Bani Hamid area. The seismicity distribution between two earthquake sequences reveals a noticeable gap that may be a site of a future event. The source parameters (seismic moment, moment magnitude, fault radius, stress drop and displacement across the fault) were also estimated from displacement spectra. The moment magnitudes were very consistent with waveform inversion. The recent deployment of seismic networks in Dubai and Oman reveals tectonic activity in the northern Oman Mountains that was previously unknown. Continued observation and analysis will allow for characterization of seismicity and assessment of seismic hazard in the region.     

Laboratory soil piping and internal erosion experiments: evaluation of a soil piping model for low‐compacted soils

Mechanistic models have been proposed for soil piping and internal erosion on well‐compacted levees and dams, but limited research has evaluated these models in less compacted (more erodible) soils typical of hillslopes and streambanks. This study utilized a soil box (50 cm long, 50 cm wide and 20 cm tall) to conduct constant‐head, soil pipe and internal erosion experiments for two soils (clay loam from Dry Creek and sandy loam from Cow Creek streambanks) packed at uniform bulk densities. Initial gravimetric moisture contents prior to packing were 10, 12 and 14% for Dry Creek soil and 8, 12, and 14% for Cow Creek soil. A 1‐cm diameter rod was placed horizontally along the length of the soil bed during packing and carefully removed after packing to create a continuous soil pipe. A constant head was maintained at the inflow end. Flow rates and sediment concentrations were measured from the pipe outlet. Replicate submerged jet erosion tests (JETs) were conducted to derive erodibility parameters for repacked samples at the same moisture contents. Flow rates from the box experiments were used to calibrate the mechanistic model. The influence of the initial moisture content was apparent, with some pipes (8% moisture content) expanding so fast that limited data was collected. The mechanistic model was able to estimate equivalent flow rates to those observed in the experiments, but had difficulty matching observed sediment concentrations when the pipes rapidly expanded. The JETs predicted similar erodibility coefficients compared to the mechanistic model for the more erodible cases but not for the less erodible cases (14% moisture content). Improved models are needed that better define the changing soil pipe cross‐section during supply‐ and transport‐limited internal erosion, especially for piping through lower compacted (more erodible) soils as opposed to more well‐compacted soils resulting from constructing levees and dams. Copyright © 2013 John Wiley & Sons, Ltd.     

Engineering Geological Properties of Building Stones from the North-Eastern Part of the Vienna Basin in the Western Carpathians

Geotechnical and Geological Engineering - This research focuses on assessing the most important physical and mechanical properties of rocks that were quarried from the north-eastern part of the...     

Evaluation of groundwater quality in the Dibdibba aquifer using hydrogeochemical and isotope techniques (Basrah Province,Iraq)

Acta Geochimica - The Dibdibba aquifer is considered to be the main source in the Al-Zubair area because agriculture depends on it to provide grazing water in the area. The groundwater well samples...     

Water quality parameters along rivers

Water samples have been collected from a part of Surma River along different points and analyzed for various water quality parameters during dry and monsoon periods. Effects of industrial wastes, municipal sewage, and agricultural runoff on river water quality have been investigated. The study was conducted within the Chattak to Sunamganj portion of Surma River, which is significant due to the presence of two major industries-a paper mill and a cement factory. The other significant feature is the conveyors that travel from India to Chattak. This study involves determination of physical, biological and chemical parameters of surface water at different points. The river was found to be highly turbid in the monsoon season. But BOD and fecal coliform concentration was found higher in the dry season. The water was found slightly acidic. The mean values of parameters were Conductivity 84–805μs; DO: dry- 5.52 mg/L, monsoon-5.72 mg/L; BOD: dry-1 mg/L, monsoon-0.878 mg/L; Total Solid: dry-149.4 mg/L, monsoon- 145.7 mg/L. A model study was also conducted and values of different model parameters were estimated.     

Comparison between inductively coupled plasma and X-ray fluorescence performance for Pb analysis in environmental soil samples

Comparison of two conventional analytical techniques such as X-ray fluorescence (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) for measuring Pb concentrations in soil samples was achieved using field and laboratory work. Seventy-three samples were collected from urban areas surrounding the large lead smelter at South Australia, as an indicator of the environment impact of smelter activity. Soil Pb concentrations were determined using hand-held XRF analyser under laboratory conditions. ICP-MS analysis on digested soils (using a microwave-assisted nitric acid digestion-extraction) was applied to validate p-XRF data. The analysis showed that Pb concentrations determined by XRF correlated with high linearity with Pb concentrations determined by ICP-MS measurements (R ² = 0.89). Statistical test (t test) was applied to the data of both methods applied without any significant difference between the two techniques. These results indicated that ICP-MS corroborated XRF for Pb soil measurements and suggests that XRF was a reliable and quick alternative to traditional analytical methods in studies of environmental health risk assessment, allowing for much larger sampling regimes in relatively shorter times and could be applied in the field.     

Air pollution hazard assessment using decision tree algorithms and bivariate probability cluster polar function: evaluating inter-correlation clusters of PM10 and other air pollutants

ABSTRACT

The automated classification of ambient air pollutants is an important task in air pollution hazard assessment and life quality research. In the current study, machine learning (ML) algorithms are used to identify the inter-correlation between dominant air pollution index (API) for PM10 percentile values and other major air pollutants in order to detect the vital pollutants’ clusters in ambient monitoring data around the study area. Two air quality stations, CA0016 and CA0054, were selected for this research due to their strategic locations. Non-linear RPart and Tree model of Decision Tree (DT) algorithm within the R programming environment were adopted for classification analysis. The pollutants’ respective significance to PM10 occurrence was evaluated using Random forest (RF) of DT algorithms and K means polar cluster function identified and grouped similar features, and also detected vital clusters in ambient monitoring data around the industrial areas. Results show increase in the number of clusters did not significantly alter results. PM10 generally shows a reduction in trend, especially in SW direction and an overall minimal reduction in the pollutants’ concentration in all directions is observed (less than 1). Fluctuations were observed in the behaviors of CO and NO_x during the day while NOx displayed relative stability. Results also show that a direct and positive linear relationship exists between the PM10 (target pollutant) and CO, SO₂, which suggests that these pollutants originate from the same sources. A semi-linear relationship is observed between the PM10 and others (O₃ and NO_x) while humidity shows a negative linearity with PM10. We conclude that most of the major pollutants show a positive trend toward the industrial areas in both stations while tra?c emissions dominate this site (CA0016) for CO and NOx. Potential applications of nuggets of information derived from these results in reducing air pollution and ensuring sustainability within the city are also discussed. Results from this study are expected to provide valuable information to decision makers to implement viable strategies capable of mitigating air pollution effects.