Assessing the effects of the climate change on land cover changes in different time periods

The present research evaluated the relation between the normalized difference vegetation index (NDVI) changes and the climate change during 2000–2014 in Qazvin Plain, Iran. Daily precipitation and mean temperature values during 2015–2040 and 2040–2065 were predicted using the statistical downscaling model (SDSM), and these values were compared with the values of the base period (2000–2014). The MODIS images (MOD13A2) were used for NDVI monitoring. In order to investigate the effects of climate changes on vegetation, the relationship between the NDVI and climatic parameters was assessed in monthly, seasonal, and annual time periods. According to the obtained results under the B2 scenario, the mean annual precipitation at Qazvin Station during 2015–2040 and 2040–2065 was 6.7 mm (9.3%) and 8.2 mm (11.36%) lower than the values in the base period, respectively. Moreover, the mean annual temperature in the mentioned periods was 0.7 and 0.92 °C higher than that in the base period, respectively. Analysis of the correlations between the NDVI and climatic parameters in different periods showed that there is a significant correlation between the seasonal temperature and NDVI (P < 0.01). Moreover, the NDVI will increase 0.009 and 0.011 during 2015–2040 and 2040–2065, respectively.     

Estimation on ureolysis-based microbially induced calcium carbonate precipitation progress for geotechnical applications

There are some key challenges in the geotechnical applications of microbially induced CaCO₃ precipitation technique. These challenges mainly arise from lack of enough control on precipitation patterns within the soil. Monitoring precipitation progress in treatment solution (biogrout) before injection provides useful information on controlling the precipitation pattern. In this study, a hybrid of electrical conductivity change measurements and precipitation mass measurements was proposed for the monitoring. The results were described as characteristic curves which would provide useful information on interpreting, estimating, and steering the precipitation pattern within the soil. The effects of some influencing factors on the precipitation patterns were also statistically investigated. XRD, FTIR, and SEM were used for the microscale identification analysis of the precipitated solids.     

A thirty-year artificial recharge experiment in a coastal aquifer in an arid zone: The Teboulba aquifer system (Tunisian Sahel)

With the increased demand for groundwater resulting from fast demographic growth, accelerated urbanization, economic and agricultural activity diversification, and the increase of per capita consumption, ground water resources, in particular in coastal regions, remain relatively low, compared to demand. The groundwater quality and piezometric variations result mainly from intensive exploitation, agricultural activities and the intrusion of seawater. This phenomenon is observed mostly in semi-arid areas, such as the oriental Sahel of Tunisia, where an apparent reduction in rainfall in recent years can be seen. Groundwater becomes overexploited especially as its natural recharge by rainwater does not succeed in maintaining the hydrologic balance. The imbalance between water demand and resources induces the degradation of the water quality. In such a case, the artificial recharge of water-table aquifers by water from dams is a credible alternative to improve the hydrodynamic and physicochemical conditions of the groundwater. Like most coastal aquifers, the Teboulba water-table aquifer is threatened by overexploitation for at least three decades. This threat appears by a considerable piezometric level drop and by water salinisation, due to seawater intrusion. Given this alarming situation, since 1971, artificial recharge through wells with surface water from a dam was tested in order to restore the water levels and to improve water quality. The piezometric and chemical surveys of the Teboulba aquifer permitted one to describe the temporal and spatial piezometric and geochemical conditions of the aquifer and to show the effect of the artificial recharge. Indeed, the artificial recharge undertaken since 1971 made the geochemical and piezometric conditions of the Teboulba aquifer improve. This example is a rare, well-documented case-study of the benefits of artificial recharge in a coastal aquifer, over the long term.     

Dynamic stress concentration near a fluid-filled permeable borehole induced by general modal vibrations of an internal cylindrical radiator

Stress distribution in the vicinity of a permeable cylindrical cavity surface (borehole wall) arising due to modal vibrations of an internal cylindrical radiator of infinite extent is studied. Biot phenomenological model is used to represent the behavior of sound in the fluid-saturated elastic porous medium and closed-form solution in the form of an infinite series is developed. A numerical example for the infinite cylindrical surface excited in vibrational modes of zeroth and first order while immersed in a water-filled cavity embedded within a water-saturated Ridgefield Sandstone environment is presented and several limiting cases are examined. Effects of axial and radial vibration frequencies, porosity, frame stiffness, and interface permeability condition on stress distribution at the borehole surface are presented and discussed.     

Impact of treated sewage sludge application on phosphorus release kinetics in some calcareous soils

Treated sewage sludge contains significant amount of phosphorus and is widely used in agriculture. Kinetics of P release in soils is a subject of importance in soil and environmental sciences. There are few studies about P release kinetics in treated sewage sludge amended soils. For this purpose, sludge was mixed with ten soils at a rate equivalent to 100 Mg sludge ha⁻¹, and P desorption was determined by successive extraction using 0.01 M CaCl₂ over a period of 65 days at 25 ± 1°C. Phosphorus release rate was rapid at first (until about first 360 h) and then became slower until equilibrium was approached. Average of P released within 360 h for the unamended and amended soils was about 65 and 73% of the total desorbed P, respectively. Zero-order, first-order, second-order, power function, simplified Elovich and parabolic diffusion law kinetics models were used to describe P release. First-order, Elovich, power function and parabolic diffusion models could well describe P release in the unamended and amended soils. Correlation coefficients between P release rate parameters and selected soil properties showed that in the control soils, calcium carbonate equivalent and Olsen-extractable P; and in the amended soils, calcium carbonate equivalent, cation exchange capacity, organic matter and Olsen-extractable P were significantly correlated with P release parameters. The results of this study showed that application of sewage sludge can change P release characteristics of soils and increase P in runoff.     

The hydro geochemical characterization of ground waters in Tunisian Chott’s region.

Tunisian Chott’s region is one of the most productive artesian basins in Tunisia. It is located in the southwestern part of the country, and its groundwater resources are developed for water supply and irrigation. The chemical composition of the water is strongly influenced by the interaction with the basinal sediments and by hydrologic characteristics such as the flow pattern and time of residence. The system is composed of an upper unconfined “Plio-Quaternary” aquifer with a varying thickness of 20–200 m, an intermediate confined/unconfined “Complex Terminal” aquifer about 100 m in thickness and a deeper “Continental Intercalaire” aquifer about 150 m in thickness separated by thick clay and marl layers. The dissolution of evaporites and carbonates explains part of the contained Na⁺, Ca²⁺, Mg²⁺, K⁺, SO₄²⁻ and Cl^-, but other processes, such carbonate precipitation, also contributes to the water composition. The stable isotope composition of waters establishes that the deep groundwater (depleted as compared to present corresponding local rainfall) is ancient water recharged probably during the late Pleistocene and the early Holocene periods. The relatively recent water in the Plio-Quaternary aquifer is composed of mixed waters resulting presumably from upward leakage from the deeper groundwater.     

Seismic potential of the North Qazvin zone,Alborz

The North Qazvin region is a part of the Central Alborz Mountains in Iran and has experienced destructive earthquakes. This region is a popular and industrial zone near Tehran, capital of Iran. To identify the highest and lowest seismic hazard location and consequently the seismic zonation of this region, different parameters, such as topography, geology, tectonics and seismicity, have been focused. Accordingly, the north of Qazvin region can be divided into three subzones: western, eastern and southern. Seismic activity of the western zone is higher than the other ones and seismic potential of the eastern zone is higher than the other two zones. This zoning is also necessary for all seismic active areas to find the most dangerous zone.     

Purang Ultramafic Complex and Their Geological Origin, Southwest Tibet

<正>Neoproterozoic ophiolitic Serpentinites are common in the Arabian–Nubian Shield(ANS)of the Eastern Desert(ED)of Egypt,which were formed in arc stage in different tectonic setting.Thus they might subject to exchange with the crustal material derived from recycling subducting oceanic lithosphere.This caused metasomatism enriching     

Sensitivity analysis of parameters influencing the ice–seabed interaction in sand by using extreme learning machine

Ice gouging problem is a significant challenge threatening the integrity of subsea pipelines in the Arctic (e.g., Beaufort Sea) and even non-Arctic (e.g., Caspian Sea) offshore regions. Determining the seabed response to ice scour through the subgouge soil deformations and the keel reaction forces are important aspects for a safe and cost-effective design. In this study, the subgouge soil deformations and the keel reaction forces were simulated by the extreme learning machine (ELM) for the first time. Nine ELM models (ELM 1–ELM 9) were developed using the key parameters governing the ice–seabed interaction. The number of neurons in the hidden layer was optimized and the best activation function for the ELM network was identified. The premium ELM model, resulting in the lowest level of inaccuracy and complexity and the highest level of correlation with experimental values was identified by performing a sensitivity analysis. The gouge depth ratio and the shear strength of the seabed soil were found to be the most influential input parameters affecting the subgouge soil deformations and the keel reaction forces. A set of the ELM-based equations were proposed to approximate the ice gouging parameters. The uncertainty analysis showed that the premium ELM model slightly underestimated the subgouge soil deformation.