Pile–soil–pile interaction in pile groups with batter piles under dynamic loads

A simple analytical solution is developed for computing the dynamic interaction tensor for floating pile groups with batter piles. For this purpose, the governing differential equations are derived for an unloaded batter floating pile closely spaced to another loaded pile with the same properties. The reaction of soil against pile deformation is modeled by the springs and dashpots along the length of the pile. The soil is assumed linear viscous elastic and the pile behavior is linear elastic. The closed form solutions of governing equations are obtained using appropriate boundary conditions. The results are verified and compared with rigorous and approximate analytical solutions for vertical piles. The proposed method can be readily applied by engineers in the design of pile groups with batter piles.     

A desert in the delta: Participatory assessment of changing livelihoods induced by commercial shrimp farming in Southwest Bangladesh

In recent years, shrimp aquaculture, which is undertaken largely in the tropical countries, has experienced spectacular growth in response to expanding global demand and higher economic return. Shrimp exports bring substantial foreign exchange to the producing countries and also generate employment for various stakeholders related to this industry. Despite a number positive aspects (e.g., foreign exchange, employment and food) of shrimp farming, the industry has serious negative environmental impacts. Because of the degradation of natural resources, commercial shrimp farming imposes socio-economic costs on rural resource-reliant communities as their traditional means of food production and livelihoods are displaced. Bangladesh produces 2.5 percent of the global production of shrimp. The country earned about 400 million dollars (U.S.) from shrimp exports during 2004-2005, up from only US$3.17 million in 1971-72. Bangladesh is suffering because of unplanned expansion of this aquaculture and increasingly called as “a desert in the delta”. The purpose of this paper is to identify the impact of commercial saltwater shrimp farming on rural livelihood patterns in southwest Bangladesh using different Participatory Research methods. The authors suggest that vulnerabilities in livelihoods of the rural communities increased due to narrowing down agricultural production, income sources and natural supply of food. Other socio-economic impacts (e.g., landuse patterns, homestead and family structure, daily movement pattern and activities, drinking water, and law and order) also followed as a reaction to the changing ecological conditions. It is also found that economic benefits from shrimp cultivation to the communities was minimal or even negative due to the polarization and outflow of profits, which is augmenting the threat of poverty.     

Study of radon in soil gas,trace elements and climatic parameters around South Kordofan state,Sudan

This study was conducted primarily to measure and map radon activity concentration in soil gas and to understand the effect of geology and lithology and meteorology on radon concentration. Portable radon meter has been used for the measurement of soil gas radon at 30 different locations around Uro and Korn area in eastern Nuba Mountain South Kordofan State. The results indicate that the activity concentrations of ²²²Rn in soil gas fall within the range of 20–1,359 Bq/m³ with geometric mean of 102.80 Bq/cm³. The obtained data show that samples around Uro have anomaly of ²²²Rn concentrations than the sample around Korn. The reason could be attributed to differences in the geological structure, lithology and climate parameters. GIS predicative map has shown that the elevated levels of radon concentration were measured in North study area. Upon comparing the results with global data, it was found that the obtained values are far below the reported range of India, Slovenia, Portugal and Syria. However, the range of ²²²Rn concentrations in the soil observed in this study is significantly high relative to similar data reported from Libya. The regression analysis has shown that no correlation was noted between radon concentrations, climatic parameters and trace element.     

Determination of heavy metals in sediments of the Ergene River by BCR sequential extraction method

Utilizing the sequential extraction procedure (acid soluble, reducible, oxidizable, and residual) proposed by The European Community Bureau of Reference (BCR), the trace metals present in the sediments of the Ergene River, Turkey, were determined. The sediment samples were collected from 10 sampling sites and analyzed to identify the concentrations of cadmium, cobalt, chromium, copper, manganese, nickel, lead and zinc. The flame atomic absorption spectrometer was used for metal determination. The validation of the results was checked by the analysis of the BCR-701 standard reference material. The relationship existing between the sediment characteristics and metal fractions was identified using the correlation analysis. Hierarchical cluster analysis was performed to find out the grouping of the sampling sites based on the similarities of the heavy metals in the bioavailable fraction. When the extractable amounts of heavy metals are considered, the quantity of the mobile fractions (viz., acid soluble, reducible, and oxidizable) of the heavy metals is observed to be higher when compared with that of the immobile fraction (residual). This might be caused by the anthropogenic sources. Besides, it was statistically discovered that the organic matter, pH and clay contents could influence the bonding of the analyte metals in various forms. The cluster analysis revealed three clusters of the sampling stations, with group I (S5-8) and group II (S3, S4 and S9) showing higher environmental risks. The risk assessment code indicated that the highly mobile soluble fractions of Mn, Zn, Cd and Co created a high environmental risk which could result in negative impacts on the aquatic biota.     

Using TDR and modeling tools to investigate effects of interactive factors on preferential flow and transport in field sandy clay soil

Investigation of the extent of preferential flow and transport affected by several factors and their interactions in the vadose zone using the advanced measurement and modeling techniques is crucial for protection of groundwater from agricultural chemicals like fertilizers and pesticides. The objectives of this study were to investigate the interactive effects of factors like soil structure, initial soil water content (SWC), and application rate on preferential flow and transport using the time domain reflectometry (TDR) measurements of SWC and electrical conductivity (EC) in the plots of 12 treatments in a sandy clay field soil, applying the models (HYDRUS-1D and MACRO) to the measured data, performing Tukey test statistical analysis, and relating model parameters to basic soil properties, consequently, flow and transport characteristics. Analysis of response times and the changes in SWC and EC with time during the experiments in the profiles of the treatments confirmed the existence of preferential flow and transport at the site. As long as the other factors or conditions were constant; undisturbed versus disturbed soil, wet versus dry initial SWC, and high versus low application rate caused preferential flow and transport in the soil based on the TDR measurements. Overall HYDRUS-1D had better performance than MACRO in the simulations of the measured data. These results suggest that different scales of these factors in different field soils need to be further studied for better understanding the flow and transport processes in the vadose zone.     

Land subsidence susceptibility mapping at Kinta Valley (Malaysia) using the evidential belief function model in GIS

Land subsidence is one of the frequent geological hazards worldwide. Urban areas and agricultural industries are the entities most affected by the consequences of land subsidence. The main objective of this study was to estimate the land subsidence (sinkhole) hazards at the Kinta Valley of Perak, Malaysia, using geographic information system and remote sensing techniques. To start, land subsidence locations were observed by surveying measurements using GPS and using the tabular data, which were produced as coordinates of each sinkhole incident. Various land subsidence conditioning factors were used such as altitude, slope, aspect, lithology, distance from the fault, distance from the river, normalized difference vegetation index, soil type, stream power index, topographic wetness index, and land use/cover. In this article, a data-driven technique of an evidential belief function (EBF), which is in the category of multivariate statistical analysis, was used to map the land subsidence-prone areas. The frequency ratio (FR) was performed as an efficient bivariate statistical analysis method in order compare it with the acquired results from the EBF analysis. The probability maps were acquired and the results of the analysis validated by the area under the (ROC) curve using the testing land subsidence locations. The results indicated that the FR model could produce a 71.16 % prediction rate, while the EBF showed better prediction accuracy with a rate of 73.63 %. Furthermore, the success rate was measured and accuracies of 75.30 and 79.45 % achieved for FR and EBF, respectively. These results can produce an understanding of the nature of land subsidence as well as promulgate public awareness of such geo-hazards to decrease human and economic losses.     

The Dynamics of Ejecting Stellar Systems

We consider the ejection of one stellar system from the centre of another stellar system, representing both by Plummer models. Using the impulsive appoximation, we derive analytically the overall and differential energy changes and also the mass escape from the systems. We compare the results with those obtained for colliding systems.We find that the disruptive effects are considerably less in the case of ejection. If the ejected system is compact, it escapes with negligible disruptive effects.In the case of ejections, stars are also accelerated in the direction of motion of the system. Using a dimensionless parameter λ defined as the ratio of the squares of the stellar velocity perturbations in the direction of motion of the system and perpendicular to it, we find a significant difference between ejecting systems and colliding systems. In fast head-on collisions of spherical stellar systems, the systems become elongated in the direction perpendicular to the direction of motion whereas in the case of ejecting systems, they also become elongated in the direction of motion. These effects are more pronounced in the outer regions of the smaller system and the innner regions of the bigger system. These effects are enhanced if the ejected system is compact.     

Usefulness of electrical and magnetic methods in finding buried structure of the Alabanda Ancient Cistern in Çine Town,Aydın City,Turkey

In this paper, the Electrical Resistivity Tomography and magnetic methods, including Tilt Angle and Euler Deconvolution, have been used in a comperative manner to determine the lineaments and depths of buried archeological structures. The zero contours of the tilt angle correspond to the boundaries of buried structures and the half distance between ±π/4 rad corresponds to the depth to the top of the structures. Also, in order to estimate the positions and depths of buried structures in the study area, the Euler Deconvolution method was applied to the total magnetic field data. All of the methods have a good correlation about determination of the horizontal locations and depths of the buried structures. The archeological excavations based on the geophysical investigations have demonstrated that the buried structure is an ancient cistern building because of the unearthed pools. Therefore, the interpretations of the geophysical methods and fiction of the paper were made according to the ancient cistern building. With this study, a buried ancient cistern structure was modeled and revealed by the geophysical methods for the first time. Additionally, using of these geophysical techniques in a comparative manner for the archaeogeophysical work will greatly contribute to future studies.