Effect of heavy metal and alkali contamination on the swelling properties of kaolinite

One of the most important factors that determine engineering properties of soils are the type and the amount of clay present in soil. Kaolinite being a very common and non-swelling clay mineral in soil was chosen as the medium, and significance of the change in swelling property of kaolinite due to contaminant-clay interaction was investigated. The amount of change in swelling percentages of the kaolinite due to contamination with 10,000 ppm solutions of Pb(NO₃)₂ and Zn(NO₃)₂ was determined using oedometers. For uncontaminated kaolinite, the amount of swell was determined as 2.2%. For Pb-contaminated and Zn-contaminated kaolinite, these values reached to 5.8 and 5.3%, respectively. Besides heavy metals, kaolinite was also contaminated with 4 N NaOH. The biggest change in the amount of swelling was obtained from NaOH-contaminated kaolinite which is 13.9%. In addition to swelling percentages, swelling pressures were also determined. The swelling pressure of the uncontaminated kaolinite was found as 1.06 N/cm². For Zn and Pb-contaminated kaolinite, this value reached up to 2.0 and 2.6 N/cm². The NaOH-contaminated kaolinite has the greatest swelling pressure which was 230 N/cm².     

Seismic damage assessment based on regional synthetic ground motion dataset: a case study for Erzincan,Turkey

Estimation of seismic losses is a fundamental step in risk mitigation in urban regions. Structural damage patterns depend on the regional seismic properties and the local building vulnerability. In this study, a framework for seismic damage estimation is proposed where the local building fragilities are modeled based on a set of simulated ground motions in the region of interest. For this purpose, first, ground motion records are simulated for a set of scenario events using stochastic finite-fault methodology. Then, existing building stock is classified into specific building types represented with equivalent single-degree-of-freedom models. The response statistics of these models are evaluated through nonlinear time history analysis with the simulated ground motions. Fragility curves for the classified structural types are derived and discussed. The study area is Erzincan (Turkey), which is located on a pull-apart basin underlain by soft sediments in the conjunction of three active faults as right-lateral North Anatolian Fault, left-lateral North East Anatolian Fault, and left-lateral Ovacik Fault. Erzincan city center experienced devastating earthquakes in the past including the December 27, 1939 (Ms = 8.0) and the March 13, 1992 (Mw?=?6.6) events. The application of the proposed method is performed to estimate the spatial distribution of the damage after the 1992 event. The estimated results are compared against the corresponding observed damage levels yielding a reasonable match in between. After the validation exercise, a potential scenario event of Mw?=?7.0 is simulated in the study region. The corresponding damage distribution indicates a significant risk within the urban area.     

Automated 1D interpretation of resistivity soundings by simultaneous use of the direct and iterative methods*

Noise contamination of measured data greatly affects the final results of inversion. Three types of noise source — random and systematic errors and the uncertainties due to the inadequacy of the mathematical model in representing the actual physical conditions — are discussed in the framework of resistivity sounding data. Two methods are proposed for describing these uncertainties. The first possibility is to smooth the measured data by a combination of simple fitting functions that satisfies the ‘1D smoothness’ criteria and consequently simulates the behaviour of a 1D Schlumberger apparent resistivity curve. The second method is to derive weight coefficients from the differences between the measured and the smoothed data sets. Both methods are carried out under the control of the interpreter. The relative merits and drawbacks of the direct and iterative interpretation methods used for the estimation of the parameters of the layered earth model are summarized. Two variants of the combination of these methods are presented to obtain more powerful and automatic interpretation schemes. In the sequential interpretation, an initial guess supplied by the direct method is improved by the iterative method to obtain a reasonable fit between the measured data and the model response. In the simultaneous interpretation, the successive application of the direct and iterative methods is carried out, starting from the first branch of the apparent resistivity curve. The operation is then shifted to subsequent branches that represent the deeper parts of the geoelectric section. This is similar to the data acquisition applied in direct current sounding in which the depth penetration is increased by expanding the current electrode spacings. The proposed sequential and simultaneous interpretation algorithms require minimum aids and efforts of the interpreter.     

Nonlinear meta-models for conceptual seakeeping design of fishing vessels

The scope of this paper is to develop the nonlinear meta-models for seakeeping behaviour, considering the fishing vessels. These models are intended to be inserted either in a multiattribute design selection process or in a comprehensive multiobjective optimization procedure. For this purpose, seakeeping data of fishing vessels in regular head waves are used to develop meta-models of transfer functions of heave, pitch and vertical acceleration by nonlinear analysis. A home-made software considers two databases; the first is composed by the ship dimensions and coefficients of fishing vessels, and the second is their ship motion data obtained by employing a strip-theory calculation. The meta-models are proposed to predict the vertical motion characteristics for given ranges of speed and wave length during the concept design stage. The independent variables are hull size (Δ), main dimensions (L, B, T), and some hydrostatic parameters (C_WP, C_VP, LCB, LCF, etc.). The results estimated by the software show good correspondences with the ones achieved by direct computations. The study provides additional insight on the influence of hull form parameters on seakeeping performance of small vessels having form properties and parametric range corresponding to the investigated vessels.     

Fossil findings from the Sıcak Çermik fissure ridge-type travertines and possible hominid tracks,Sivas, Central Turkey

S?cak Çermik (Sivas) is an important geothermal and recent travertine formation area in Central Anatolia. The majority of travertines found in the region comprise fissure-ridge type travertines according to morphological classification. At the location called Tepe Çermik within the travertine area, fill containing fossil bone fragments of Equus sp., Bovidae and other abundant animals formed within the fracture axis of a N–S striking fissure-ridge travertine developed under control of tectonic forces. The finds of these fossils in fissure-ridge travertines linked to tectonic forces indicates formation of a unique fossil environment created under the control of these forces. The Accelerator Mass Spectrometry Radiocarbon Dating analyses of fossils from the study area determined the fills were older than 43,000 years. The U/Th age of a sample from the most recently-formed banded travertine in the axis of the fracture was identified as 278,540 ± 18,436 years. As a result, the ages of fossils found within this fill are thought to be between 43,000 and 278,540 ± 18,436 years old. The high amount of perissodactyla and artiodactyla fossils found within fill in the axis of the fissure-ridge travertine probably indicates the presence of hominids who chose the region for hunting or settlement. The Equus sp. and Bovidae fossil samples found in the axis of the fracture indicate that in the dry and cold glacial period the paleogeography in a large portion of Anatolia comprised desert-like steppe.     

A technique for improving MODIS standard snow products for snow cover monitoring over Eastern Turkey

Daily snow cover maps at 500 m resolution are available from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on NASA's Terra and Aqua satellites. However, information of the ground can only be obtained during clear sky conditions. In addition, the spectral similarity between clouds and snow in the visible part of the spectrum causes some ambiguities in separation of them. The dynamic behavior of clouds with their tendency to move faster often enables discrimination between cloud and snow, since snow remains relatively stationary. In this study, a daily merging methodology to combine Terra and Aqua based snow maps are proposed, and the benefits of this combination are evaluated. The methodology was tested for Eastern Turkey covering the period from December 2002 to March 2003. Merged maps derived from the standard daily snow maps from Terra (MOD10A1) and Aqua (MYD10A1) reduce the cloud cover present in any one image alone, provide better representation of the surface snow cover, and indicate better agreement with ground snow measurements than when either one is used alone. For “on the ground data date” analyses yielded 31% match ratios for MOD10A1 and MYD10A1, whereas combined images enabled 38%. One- to 2-day temporal window shifting enabled further 7% and 5% improvements in match ratios, respectively. The maximum improvement of 25% was achieved in January of 2003. The proposed methodology provides an easy and effective way to improve snow cover maps with little effort and provides fewer cloud-contaminated images for snow monitoring, for hydrology, and water resource management.     

Biodegradability Assessment and Treatability of High Strength Complex Industrial Park Wastewater

Industrial park wastewater (IPWW) includes complex non‐biodegradable organic compounds. A wastewater treatability study using biodegradability assessment approach was carried out for an industrial park housing mainly textile and machinery sectors. Biodegradable and inert chemical oxygen demand (COD) fractions with soluble and particulate counterparts were experimentally estimated by implementing respirometric methods. Aerobic batch test methods and oxygen uptake rate profiles were used to map kinetic parameters and COD fractions. Denitrification potential was also determined by application of anoxic batch tests. Relevant kinetic constants, stoichiometric, and design parameters were determined for biological processes. Tests were carried out for raw and physico‐chemically pre‐treated IPWW. Hence, it was aimed to assess the effects and necessity of pre‐treatment on biological processes. Biological mineralization, nitrification, and denitrification processes were also designed and tested using a bench scale continuous treatment model for pre‐treated IPWW. The sum of initial inert soluble COD fraction and production of soluble microbial products decreased about 25% for the case of pre‐treated IPWW as compared to raw IPWW. Eighty‐three percent total COD and 89% total Kjeldahl nitrogen removal efficiencies were attained for the modeling experiments of pre‐treated IPWW. Results showed the significance of pre‐treatment if complex strength industrial wastewaters are to be biologically treated.