Investigation on the Levels of Heavy Metals,Polycyclic Aromatic Hydrocarbons,and Polychlorinated Biphenyls in Sewage Sludge Samples and Ecotoxicological Testing

This article reports the levels of heavy metals, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) in sewage sludges taken from two wastewater treatment plants (WWTPs) in Konya (Turkey) as well as their toxicity. The concentrations of heavy metals, including Cd, Cr, Cu, Ni, Pb, Zn in sludge samples from plant #2 did not exceed the limits described in both Turkish and European Union (EU) regulations. The similar result was observed in samples obtained from plant #1, except for sludge taken in May 2010. The ΣPAHs concentration ranging from 960 to 7680 µg/kg dry matter shows that sewage sludges from plant #1 could be used for agricultural purpose. However, sewage sludges from plant #2 (ΣPAHs: 1077–17 509 µg/kg dry matter) was not suitable for using in agriculture. The concentrations of ΣPCBs in all investigated sludges from plant #1 (7.46–709.36 µg/kg dry matter) and plant #2 (14.12–788.47 µg/kg dry matter) were lower than the limits reported in Turkish and EU regulations. The probable sources of PAHs and PCBs in sludges were also determined. The ecotoxicological tests examined on Vibrio fischeri and Lepidium sativum organisms showed that sludges from plant #1 had no significant toxic effect, while sludges from plant #2 had acute toxic property. Finally, all the results showed that sewage sludges from plant #1 had potential for being used in agriculture.     

Distribution and chemical speciation of heavy metals in the surficial sediments of the Bak?r?ay and Gediz Rivers, Eastern Aegean

The pollution of aquatic ecosystem by heavy metals has assumed serious proportions due to their toxicity and accumulative behaviour. The toxicity and fate of the water borne metal is dependent on its chemical form and therefore quantification of the different forms of metal is more meaningful than the estimation of its total metal concentrations. A five-step sequential extraction procedure was applied for the determination of the distribution of seven elements (Pb, Cr, Cu, Mn, Zn, Ni, Fe) in sediment samples collected from Bakır?ay and Gediz Rivers. According to this study, the results of metals are mostly retained in the residual, oxidizable and reducible fractions. Based on the chemical distribution of metals, we found that Cr, Zn, Cu and Ni are the most non-mobile metals. Pb is the metal that showed the highest percentages in the residual and reducible fractions. Mn is present in the higher percentages in the reducible and carbonate fractions. However, Fe is present in the greatest percentages in the residual fraction, which implies that these metals are strongly linked to the sediments. The risk assessment code as applied to the present study shows that about 12.3–26.9 and 15.7–33.5% of manganese at most of the sites exist in carbonate fraction in the Bakır?ay and Gediz Rivers, respectively. Therefore, Mn comes under the medium risk category in the Bakır?ay and high-risk category in the Gediz River. Speciation pattern of Cu, Zn, Pb, Cr, Ni, Fe shows low to medium risk to aquatic environment health in both rivers.     

Curie Point Depth Investigation of Central Anatolia,Turkey

The residual aeromagnetic total field intensity anomalies in central Anatolia were calculated from the regional aeromagnetic anomalies surveyed by the Mineral Research and Exploration (MTA) of Turkey. The residual aeromagnetic data were analyzed to produce Curie point estimates by the method of OKUBO et al. (1985). The Curie point depth of central Anatolia varies from 7.9 km and 22.6 km. The shallowest Curie point depths were observed around the Cappadocia and Erciyes Volcanic complexes in central Anatolia. A good correlation was deduced between the Curie point depths and the heat-flow data measured previously, which is most certainly important for the geothermal resources of the region. The shallow Curie point depths also correlate well with the hot spring locations in central Anatolia.     

Interaction of multiple cracks and formation of echelon crack arrays

Fracturing of rock under compression is a product of a series of processes, including nucleation, growth, interaction and coalescence of multiple microcracks. The formation of echelon arrays of microcracks and macrocracks is one of the crucial rings in the processes. We use a superposition and asymptotic approximation technique to analyse the interaction of multiple cracks with various geometrical configurations. It is shown that crack geometry has a strong influence on crack interaction. Echelon crack arrays produce the strongest interaction and are the preferred geometrical configuration for multiple cracks prior to the formation of through-going shear fractures. This technique provides parameter-dependent global behaviour, and is more efficient and easier to use.     

The morphology and chemistry of K-feldspar megacrysts from Ikizdere Pluton: evidence for acid and basic magma interactions in granitoid rocks, NE-Turkey

Ikizdere Pluton consists of granite, granodiorite, tonalite, monzonite, quartz monzonite containing pinkish colored K-feldspar megacrysts (KFMs). The crystal sizes of the KFMs range from 1 to 4 cm. The lath-shaped megacrysts are uniformly (i.e., randomly) distributed in the host plutonic rocks and have mafic and felsic inclusions whose crystal sizes are smaller than 1 mm. The crystal inclusions are biotite, slightly annitic in composition with X_Mg[=Fe_tot/(Fe_tot+Mg)]=0.50-0.58, amphibole (magnesio-hornblende, X_Mg[=Mg/(Mg+Fe_tot)]=0.70-0.79), iron-titanium oxide (low titanium magnetit and ilmenite), plagioclase (Ab₇₅₋₂₅An₆₅₋₃₅) and as minor quartz. The compositions of the KFMs range from Or₉₅Ab₅An₀ to Or₈₂Ab₁₇An₁. BaO contents of the megacrysts increase from core to rim. The mafic and felsic inclusions are compositionally similar those of the host rocks.The chemical and textural features of K-feldspar are typical for megacrysts that grew as phenocrysts in dynamic granitoidic magma systems. The overgrowth of KFMs and mafic magma injections (magma mixing) may be related to temperature, pressure and compositional fluctuations in the magma chamber. Remnant of earlier formed K-feldspar crystals remain in the felsic magma system, while the mafic injection can decompose some earlier precipitated KFMs. The remnant of K-feldspar remaining after mafic injection are overgrown by rapid diffusion of Ba, K and Na elements in liquid phase, during the later stages of crystallization of the host magma.     

iSERVO: Implementing the International Solid Earth Research Virtual Observatory by Integrating Computational Grid and Geographical Information Web Services

We describe the goals and initial implementation of the International Solid Earth Virtual Observatory (iSERVO). This system is built using a Web Services approach to Grid computing infrastructure and is accessed via a component-based Web portal user interface. We describe our implementations of services used by this system, including Geographical Information System (GIS)-based data grid services for accessing remote data repositories and job management services for controlling multiple execution steps. iSERVO is an example of a larger trend to build globally scalable scientific computing infrastructures using the Service Oriented Architecture approach. Adoption of this approach raises a number of research challenges in millisecond-latency message systems suitable for internet-enabled scientific applications. We review our research in these areas.     

Evaluation of parameters affecting earthquake damage by decision tree techniques

Earthquake damages are assessed based on a holistic approach using structural as well as non-structural factors to model earthquake damage distributions with Decision Tree Techniques, using the Answer Tree program and the damage data from recent major earthquakes in Turkey. The damage dataset consists of approximately 9,400 buildings that were surveyed to evaluate the factors affecting building damage after Erzincan [1992], Dinar [1995], and Kocaeli [1999] earthquakes. The earthquake damage is defined as the dependent variable, while earthquake magnitude (M), intensity (I) in the city, peak ground acceleration (PGA) in each city, epicenter distance (ED), building types (BT), number of storeys (NS), presence of soft storey (SS), building position (BP) on the site, and site conditions (SC) are independent variables in the proposed model. The damage level (DL) was classified with respect to red, yellow, and green codes. The main purpose was (1) to identify the factors controlling building damage during earthquakes; (b) to determine the most significant factor; (c) to evaluate the effects of different factors for different earthquakes; (d) to develop damage distribution models for different subgroups based on the Decision Tree Techniques.

Spectroscopic study of the supergiant star 6 Cassiopeiae

Twenty-five coudé spectrograms (22 with dispersion 12 Å mm^–1 and three 7 Å mm^–1) of 6 Cassiopeiae (A3 Ia) have been studied. The observations were made at the Haute Provence Observatory. The results of the analysis suggest a correlation between the variations of the equivalent widths, the microturbulence and the radial velocity. The radial velocity and turbulent velocity present a rapid variation with time, even in intervals as short as about an hour. The hydrogen lines are slightly asymmetric but the strongest Feii lines are clearly asymmetric. We found that the amount of asymmetry of the strongest Feii lines (I>6) correlates with the loggf value, with the estimated laboratory intensityI, and with the equivalent widthW .The observations have been made at the Astronomical Observatory of Haute Provence (CNRS). This work has been supported by TUBITAK (Scientific and Technical Research Council of Turkey), and partially by CNR (Consiglio Nazionale delle Ricerche) of Italy.     

Artificial neural networks and their application to assessment of ultimate strength of plates with pitting corrosion

The potential for the structural capability degrading effects of both corrosion and fatigue induced cracks are of profound importance and must be both fully understood and reflected in vessel's inspection and maintenance programme. Corrosion has been studied and quantified by many researchers, however its effect on structural integrity is still subject to uncertainty, particularly with regards to localized corrosion. The present study is focused on assessing the effects of localized pitting corrosion on the ultimate strength of unstiffened plates. Over 265 non-linear finite-element analyses of panels with various locations and sizes of pitting corrosion have been carried out. The results indicate that the length, breadth and depth of pit corrosion have weakening effects on the ultimate strength of the plates while plate slenderness has only marginal effect on strength reduction. Transverse location of pit corrosion is also an important factor determining the amount of strength reduction. When corrosion spreads transversely on both edges, it has the most deteriorating effect on strength. In addition, artificial neural network (ANN) method is applied to derive a formula to predict ultimate strength reduction of locally corroded plates. It is found out that the proposed formulae can accurately predict the ultimate strength of locally corroded plates under uniaxial in-plane compression.