Kerman Clay Improvement by Lime and Bentonite to Be Used as Materials of Landfill Liner

Kerman province, located in the south eastern Iran, is dominated with clays which can be used in different projects. The liner system within a landfill is constructed to control leachate migration and can be constructed by low permeable natural soils or plastic lining materials, environmentally however, natural materials is preferred that usually need to be amended in order to meet requirements recommended by environmental agencies. This research examines the possibility of using the Kerman collapsible clay as a liner layer material. A set of laboratory test was conducted on pure soil samples and additive treated samples. The moderate collapse potential of the used soil is decreased with wet compaction and under the effect of additive-soil reactions. Laboratory investigations showed that lime and bentonite treatment improved the hydraulic conductivity. The results revealed hydraulic conductivities on the order of 10^?8 m/s. The obtained values met the 1.0E?07 m/s criterion required by Iranian standards. Unconfined compression tests were also performed on pure soil and additive amended samples. The unconfined compression strength values demonstrated gradual decreases with the addition of bentonite and considerable increases with adding lime such that with adding 1% lime the unconfined compression strength increased by 75%. This study verified that the Kerman collapsing clay can be used as a liner material using lime and bentonite as additives.     

Regional improvement of global geopotential models using GPS/Leveling data

Studia Geophysica et Geodaetica - Global geopotential models are widely used in the remove-compute-restore technique for local gravity field modeling. In this paper, a method for regional...     

Geospatial modeling to identify the effects of anthropogenic processes on landscape pattern change and biodiversity

This research used geospatial data to quantify biodiversity changes and landscape pattern change to track anthropogenic impacts of such changes at the Mouteh Wildlife Refuge (MWR), Isfahan, Iran. Satellite image duration of four decades, LandSat_1-5, and IRS-P6 data were used to develop land cover classification maps for 1971, 1987, 1998, and 2011. The number and size of land cover patches, the degree of naturalness, and the diversity indices were calculated and compared for a 40-year period. The results showed an increasing concern with regard to unplanned human activities. Some improvements of the natural landscape also occurred in the core protected zone of the study area. The number and size of land cover patches, the degree of naturalness, and the diversity indices were calculated. Overall changes in natural land use between 1971 and 1998 at MWR showed that the number of patches for natural land use has increased, but it also showed a decrease in 2011. Similar changes were observed for seminatural land use. Within the artificial classes, the number and area of patches were higher and the largest patch occurred in 2011. The maximum variation of diversity is related to the year 2011. The results showed an increasing concern with regard to unplanned human activities. Some improvements of the natural landscape also occurred in the core protected zone of the study area. Remote sensing and geographic information system offers an important means of detecting and analyzing temporal changes occurring in our landscape.     

Evolution of filamentary molecular clouds in the presence of magnetic fields

The purpose of this paper is to explore the effect of magnetic fields on the dynamics of magnetized filamentary molecular clouds.We suppose there is a filament with cylindrical symmetry and two components of axial and toroidal magnetic fields.In comparison to previous works,the novelty in the present work involves a similarity solution that does not define a function of the magnetic fields or density.We consider the effect of the magnetic field on the collapse of the filament in both axial and toroidal directions and show that the magnetic field has a braking effect,which means that the increasing intensity of the magnetic field reduces the velocity of collapse.This is consistent with other studies.We find that the magnetic field in the central region tends to be aligned with the filament axis.Also,the magnitude and the direction of the magnetic field depend on the magnitude and direction of the initial magnetic field in the outer region.Moreover,we show that more energy dissipation from the filament causes a rise in the infall velocity.     

A recent scenario of mass wasting and its impact on the transportation in Alborz Mountains, Iran using geo-information technology

Mass movements or mass wasting is being considered as one of the severe forms of natural disasters. Iran is geographically located in the Alps–Himalaya seismicity belt. It has a high potential to mass wasting. This seismic phenomenon creates landslides and rock falls in the high mountains of Alborz and Zagros. These mass movements and various types of slides can be systematically assessed and mapped through traditional mapping frameworks using geo-information technologies. The geo-information-based technology offers the earth scientist to study and map various types of mass movement and stability of slopes. In this study, we used field data coupling with the tectonic-related factors to provide a solution for slope-related hazards. Firstly, various geological and geomorphological factors such as lineaments and faults, vegetation, lithology, slope, drainage, land use/land cover, seismicity and roads network were extracted and compiled using geo-information technology. This is because the factors mentioned above play important role in the instability of the region. Then, the study area was divided into four regions based on the rate of mass wasting and its degree of vulnerability. The results of this study showed that the erosion in Karaj formation is severe. Additionally, this research also reveals that the hydrothermal solutions caused by the erosional activities have influenced the glassy element of tuffs and subsequently changed into the clays. This change has caused the tuffs to be relatively unstable. Further, it is evident that the chemical and physical weathering has had a big impact on it whilst most of the mass wasting has occurred within the unstable tuffs of Karaj formation. Finally, the paper concluded that the recent construction of the new roads in the region has increased the potential danger for generating the mass wastes and thus makes the region more unstable.     

Hydrocarbon Vertical Continuity Evaluation in the Cretaceous Reservoirs of Azadegan Oilfield,Southwest of Iran: Implications for Reservoir Geochemistry

A collection of data obtained from analytical methods in geochemistry along with the reservoir engineering and geologic data were used to investigate the reservoir continuity in the Cretaceous Fahliyan, Gadavan, Kazhdumi and Sarvak reservoirs of the super-giant Azadegan oilfield, SW Iran. The geochemical data indicate that the oil samples, with medium to high level of thermal maturity, have been generated from the anoxic marine marl/carbonate source rock(s). The Sargelu(Jurassic) and Garau(Creta...     

A Poroelastic Description of Permeability Evolution

Pore pressure changes in a geothermal reservoir, as a result of injection and/or production of water, result in changes of stress acting on the reservoir rock and, consequently, changes in the mechanical and transport properties of the rock. Bulk modulus and permeability were measured at different pressures and temperatures. An outcropping equivalent of Rotliegend reservoir rock in the North German Basin (Flechtinger sandstone) was used to perform hydrostatic tests and steady state fluid flow tests. Permeability measurements were conducted while cycling confining pressure; the dependence of permeability on stress was determined at a constant downstream pressure of 1 MPa. Also, temperature was increased stepwise from 30 to 140 °C and crack porosity was calculated at different temperatures. Although changes in the volumes of cracks are not significant, the cracks control fluid flow pathways and, consequently, the permeability of the rock. A new model was derived which relates microstructure of porosity, the stress–strain curve, and permeability. Porosity change was described by the first derivative of the stress–strain curve. Permeability evolution was ascribed to crack closure and was related to the second derivative of the stress–strain curve. The porosity and permeability of Flechtinger sandstone were reduced by increasing the effective pressure and decreased after each pressure cycle.     

Hydrodynamic behavior of Kangan gas-capped deep confined aquifer in Iran

The Kangan aquifer (KA) is located beneath the Kangan gas reservoir (KGR), 2,885 m below the ground surface. The gas reservoir formations are classified into nine non-gas reservoir units and eight gas reservoir units based on the porosity, water and gas saturation, lithology, and gas production potential using the logs of 36 production wells. The gas reservoir units are composed of limestone and dolomite, whereas the non-gas reservoir units consist of compacted limestone and dolomite, gypsum and shale. The lithology of KA is the same as KGR with a total dissolved solid of 333,000 mg/l. The source of aquifer water is evaporated seawater. The static pressure on the Gas–Water Contact (GWC) was 244 atm before gas production, but it has continuously decreased during 15 years of gas production, resulting in a 50 m uprising of the GWC and the expansion of KA water and intergranular water inside the gas reservoir. The general flow direction of the KA is toward the northern coast of the Persian Gulf due to the migration of water to the overlying formations via a trust fault. The KA is a gas-capped deep confined aquifer (GCDCA) with special characteristics differing from a shallow confined aquifer. The main characteristics of a GCDCA are unsaturated intergranular water below the confining layers, no direct contact of the water table (GWC) with the confining layers, no vertical flow via the cap rock, permanent uprising of the GWC during gas production, and permanent descend of GWC during water exploitation.     

Bedload resistance in supercritical flow

The movement of bedload in subcritical flow produces additional roughness as compared to flow in a rigid bed. The magnitude of this bed load roughness is proportional to the thickness of the sediment layer moving along the bed, the particle size and the sediment concentration. In a supercritical flow, however, further resistance is expected due to the momentum absorption by the high flow velocity. In this study the effect of sediment movement on the flow resistance in supercritical flow was experimentally investigated. The experiments included flows over smooth and rough beds carrying sediment of mean diameters D50=2.80, 5.42 and 7.06 mm in a rigid rectangular channel. The results show that the sediment transport may increase the friction factor by up to 90% and 60% in smooth and rough beds, respectively. Bedload extracts its momentum from the flow, which causes a reduction of near bed flow velocity and steeper velocity gradient near the bed resulting in an increase in shear velocity as well as in roughness height. The increase in friction factor is directly related to bedload concentration and particle size.