Vertical spatial correlation length based on standard penetration tests

The spatial correlation length (SCL), or the scale of fluctuation, is a parameter for describing the spatial variability of soil and one of the important parameters used in random field theory. Studies reporting the spatial correlation length based on real field data of offshore/nearshore sea bottom soils are rather limited in the literature, so in this study, the vertical spatial correlation length is determined using site investigation data from two sites of the southern coast of Turkey. Based on quite extensive data, the vertical spatial correlation length is estimated using four different autocovariance functions. The values are within typical ranges reported in the literature for similar soil groups, both onshore and offshore. It is also noted that the widely-used exponential function almost always gives the lowest value of spatial correlation length. The results of this study add to the database of spatial correlation lengths based on real data and could be useful for future studies on reliability assessment of offshore foundations using random finite element method.     

Optimization of Gravity Concrete Dams Using the Grasshopper Algorithm (Case Study: Koyna Dam)

Geotechnical and Geological Engineering - The aim of this study is to optimize the geometric dimensions of the Koyna concrete weight dam with and without seismic forces using the grasshopper...     

A New Polyelectrolyte Dosing Method: Injection into Deep Bed Filter Media

The aim of this paper was to investigate a novel method of polyelectrolyte injection into deep bed filter media. The raw water and the filter media used in the pilot filters were obtained from the Omerli Reservoir that supplies one million m³/day of water to the greater city of Istanbul. A cationic polyelectrolyte was injected at the entrance of the filter and at different depths of the sand bed. The effect of polyelectrolyte injection location and method was evaluated by measuring the effluent turbidity, effluent particle count, and the head losses at different locations of the sand media. It was observed that the simultaneous injection of the polyelectrolyte on top of the filter bed and at the center can lengthen the filter run time while achieving an effluent turbidity as low as 0.06 NTU (nephelometric turbidity unit) and 4 log (99.99%) particle removal.     

Local indications of climate changes in Turkey: Bursa as a case example

This study aims to put out on what ratio Bursa province, one of the important heavy industry regions of Turkey, has been affected climatic process called “Global Warming” or “Climate Change”. For this intend climatic measurement results from Bursa center, top of Uludağ Mount, Yenişehir and Keles meteorological stations were used. These measurements were taken as minimum temperature at night-time, maximum temperature at day-time, and mean temperature, mean pressure, insolation intensity, insolation duration, mean wind speed, minimum temperature above soil, soil temperatures at depths of 5, 10, and 20 cm rainfall. Overall, our statistical results showed that there was a considerable warming at statistically 1% and 5% levels in summer months, particularly in July Almost all performed measurements confirm this result. According to climatic data for thirty years (1975–2005), in the last twelve years contrary to previous 18 years, mean temperature values were higher than long-term mean value nine times (years) repetitively. Temperatures did not deviated higher than 0.5°C in six of these. At the temperatures below mean, The maximum deviation was −0.4°C.     

Sensitivity Study of Hydrodynamic Parameters During Numerical Simulations of Tsunami Inundation

This paper describes the analysis of a parameter, “hydrodynamic demand,” which can be used to represent the potential for tsunami drag force related damage to structures along coastlines. It is derived from the ratio of drag force to hydrostatic force caused by a tsunami on the structure. It varies according to the instantaneous values of the current velocities and flow depths during a tsunami inundation. To examine the effects of a tsunami in the present study, the analyses were performed using the tsunami numerical model in two altered regular-shaped basins having different bottom slopes. The simulations were implemented using a single sinusoidal wave with particular initial conditions, such as leading elevation wave and leading depression wave profiles with different wave periods. Two different initial wave amplitudes were employed to assess the diversity in the distribution of the square of the Froude number Fr ² along the coastline. The numerical results were compared quantitatively.     

Absolute properties of the neglected eclipsing B-type binary HD 194495

We present the results of the high-resolution spectroscopic observations of the neglected binary system HD 194495 (B3 IV-V+B4 V). A combined analysis of three different photometric data set (Tycho B_T and V_T photometry, H_p-band data of Hipparcos and V-band data of ASAS3 photometry) and radial velocities indicates that the system has an orbital period of 4.90494 ± 0.00005 days and an inclination of 69 ± 1 degrees. This solution yields masses and radii of M₁ = 7.57 ± 0.08 M_⊙ and R₁ = 5.82 ± 0.03 R_⊙ for the primary and M₂ = 5.46 ± 0.09 M_⊙ and R₂ = 3.14 ± 0.08 R_⊙ for the secondary. Based on the position of the two stars plotted on a theoretical H-R diagram, we find that the age of the system is ?28 Myr, according to stellar evolutionary models. The spectroscopic and photometric results are in agreement with those obtained using theoretical predictions.     

A Comparative Study for 3D Surface Modeling of Coal Deposit by Spatial Interpolation Approaches

The planning stages of mining require comprehensive and detailed analyses. The proper determination of the orebody boundary is one of the most important points to provide optimum model structure and projections. The limits can be determined by different methods based on the site geology. Although some three dimensional (3D) models were proposed for providing detailed information concerning a mine deposit, developing a solid model via a 3D approach is novelty. In other words, surface modeling should be performed for creating a solid model and determining limits of the deposit. In this way, sensible generation of the surface model can be achieved. This study investigated the estimation capability of the polynomial approach, which is a novel spatial interpolation method, for modeling a coal deposit surface. The performance of the proposed model was compared with some conventional methods in the literature. The results showed that the polynomial interpolation method is an effective method to employ for surface modeling of a mine deposit.     

Dual impact on the groundwater aquifer in the Kazan Plain (Ankara, Turkey): sand–gravel mining and over-abstraction

This study explains the impact of sand–gravel mining and over-abstraction, and the response of the groundwater system in the Kazan Plain, Turkey. The plain used to be known for its fresh groundwater potential, valuable agricultural lands and natural beauty until the 1980s. According to the estimation in 1975, there was 15.5 million m³ annual useable freshwater in the Quaternary sand–gravel aquifer. Groundwater level ranged between 0 and 5 m from the surface of the plain in the 1970s. Because of the large and deep excavations by the sand–gravel pits during the past 25–30 years, the aquifer has thinned and removed entirely in some places. In addition, over-abstraction has accelerated the decline of the groundwater level, particularly in the middle and the upper part of the plain in recent years. As of 2009, about 12% of the total volume of the aquifer area removed by the pits and groundwater table has been reduced to between 5 and 20 m. The decline of the water table reaches 15–20 m in the regions where over-abstraction has taken place. To reduce the hazards to the groundwater system, the sand–gravel pits have to be banned immediately, a reclamation project applied and abstraction must be reduced.     

Estimation of soil erosion using RUSLE in a GIS framework: a case study in the Buyukcekmece Lake watershed,northwest Turkey

This study was aimed at predicting soil erosion risk in the Buyukcekmece Lake watershed located in the western part of Istanbul, Turkey, by using Revised Universal Soil Loss Equation (RUSLE) model in a GIS framework. The factors used in RUSLE were computed by using different data obtained or produced from meteorological station, soil surveys, topographic maps, and satellite images. The RUSLE factors were represented by raster layers in a GIS environment and then multiplied together to estimate the soil erosion rate in the study area using spatial analyst tool of ArcGIS 9.3. In the study, soil loss rate below 1 t/ha/year was defined as low erosion, while those >10 t/ha/year were defined as severe erosion. The values between low and severe erosion were further classified as slight, moderate, and high erosion areas. The study provided a reliable prediction of soil erosion rates and delineation of erosion-prone areas within the watershed. As the study revealed, soil erosion risk is low in more than half of the study area (54%) with soil loss <1 t/ha/year. Around one-fifth of the study area (19%) has slight erosion risk with values between 1 and 3 t/ha/year. Only 11% of the study area was found to be under high erosion risk with soil loss between 5 and 10 t/ha/year. The severe erosion risk is seen only in 5% of the study area with soil loss more than 10 t/ha/year. As the study revealed, nearly half of the Buyukcekmece Lake watershed requires implementation of effective soil conservation measures to reduce soil erosion risk.     

Assessment of advective–dispersive contaminant transport in heterogeneous aquifers using a meshless method

Groundwater solute transport phenomena typically occur in water-bearing zones with heterogeneous solute dispersive characteristics and/or media hydraulic properties. A radial basis function collocation method (RBFCM)-based numerical method was developed in order to investigate the ability of RBFCM to accurately portray solute transport phenomena under heterogeneous conditions. Simulations were performed for 1-D and 2-D transport scenarios in which scale-dependent dispersivity fields were taken into consideration and compared with available analytical solutions. Different radial basis functions (RBFs) were employed for assessing the sensitivity of the present method on the selected RBFs. The simulation results were also compared with the results of MT3DMS which is a modular three-dimensional transport model with alternative solution schemes including the method of characteristics, the implicit central finite difference and the third order total variation diminishing finite volume. The proposed model was also used to simulate a real case condition where solute transport through a two-layer soil medium had been investigated experimentally. The results showed that RBFCM represented a powerful tool for predicting the solute transport occurrence under heterogeneous conditions with high accuracy.