Some string cosmological models in Bianchi Type I space-time

We obtain some cosmological models that are exact solutions of Einstein's field equations. The metric utilized is Marder's metric which is Bianchi Type I and the curvature source is a cloud of strings which are one dimensional objects. Bianchi type cosmological models play an important role in the study of the universe on a scale which anisotropy is not ignored. In this paper we have investigated the effect of cosmic strings on the cosmic microwave background anisotropy. Various physical and geometrical properties of the model are also discussed. The solutions have reported that the cosmic microwave background anisotropy may due to the cosmic strings.     

Estimation of relative humidity based on artificial neural network approach in the Aegean Region of Turkey

The aim of this study is to estimate the monthly mean relative humidity (MRH) values in the Aegean Region of Turkey with the help of the topographical and meteorological parameters based on artificial neural network (ANN) approach. The monthly MRH values were calculated from the measurement in the meteorological observing stations established in Izmir, Mugla, Aydin, Denizli, Usak, Manisa, Kutahya and Afyonkarahisar provinces between 2000 and 2006. Latitude, longitude, altitude, precipitation and months of the year were used in the input layer of the ANN network, while the MRH was used in output layer of the network. The ANN model was developed using MATLAB software, and then actual values were compared with those obtained by ANN and multi-linear regression methods. It seemed that the obtained values were in the acceptable error limits. It is concluded that the determination of relative humidity values is possible at any target point of the region where the measurement cannot be performed.     

Rapid earthquake hazard and loss assessment for Euro-Mediterranean region

The almost-real time estimation of ground shaking and losses after a major earthquake in the Euro-Mediterranean region was performed in the framework of the Joint Research Activity 3 (JRA-3) component of the EU FP6 Project entitled “Network of Research Infra-structures for European Seismology, NERIES”. This project consists of finding the most likely location of the earthquake source by estimating the fault rupture parameters on the basis of rapid inversion of data from on-line regional broadband stations. It also includes an estimation of the spatial distribution of selected site-specific ground motion parameters at engineering bedrock through region-specific ground motion prediction equations (GMPEs) or physical simulation of ground motion. By using the Earthquake Loss Estimation Routine (ELER) software, the multi-level methodology developed for real time estimation of losses is capable of incorporating regional variability and sources of uncertainty stemming from GMPEs, fault finiteness, site modifications, inventory of physical and social elements subjected to earthquake hazard and the associated vulnerability relationships.     

Cylindrically-Symmetric and Inhomogeneous Cosmological Models with Viscous Fluid

In this paper, the Einstein field equations have been solved for cylindrically symmetric and inhomogeneous cosmological models with viscous fluid. Various physical and geometrical properties of the models are also discussed.     

Hα measurements using DEFPOS/RTT150 Telescope： Instrumentation and observations

To investigate the physical properties of HII regions and some PNe about 4' in size, a DEFPOS Fabry-Perot spectrometer has been redesigned and set up at the (Antalya/Bakirlitepe, Turkey), The spectrometer has a 4' circular field of view and a velocity resolution of 27.27 km s- 1 (a spectral resolving power of 11000) over a 200 km s-1 spectral window near Hα. This work presents the details of the newly redesigned inphysical results of our new Hα observations selected from the Reynolds et al. (2005) and Fich et al. (1990) papers. The DEFPOS system has been fully tested and the first observations of HII regions and PNe in the Galaxy are used to illustrate the power of the instrument. We feel that our first Fabry-Perot observations can provide a powerful tool for the study of objects with small angular size. In the future, we are planning to prepare a catalog including some physical properties such as radial velocity, line width, and intensity of some PNe and HII regions close to the 4' field of view.     

Comparison of soil organic carbon content,hydraulic conductivity,and particle size fractions between a grassland and a nearby black pine plantation of 40 years in two surface depths

In highlands of semiarid Turkey, ecosystems have been significantly transformed through human actions, and today changes are taking place very rapidly, causing harmful consequences such as soil degradation. This paper examines two neighboring land use types in Indagi Mountain Pass, Cankiri, Turkey, to determine effects of the conversion of Blackpine (Pinus nigra Arn. subsp. pallasiana) plantation from grassland 40 years ago on soil organic carbon (SOC) and soil erodibility (USLE-K). For this purpose, a total of 302 disturbed and undisturbed soil samples were taken at irregular intervals from two sites and from two soil depths of 0–10 cm (D₁) and 10–20 cm (D₂). In terms of SOC, conversion did not make any statistical difference between grassland and plantation; however, there were statistically significant differences with soil depth within each land use, and SOC contents significantly decreased with the soil depth (P < 0.05) and mostly accumulated in D₁. SOC values were 2.4 and 1.8% for grassland and 2.8 and 1.6% for plantation, respectively, at D₁ and D₂. USLE-K values also statistically differed significantly with the land use, and in contrast to the statistics of SOC, there was no change in USLE-K with the soil depth. Since USLE-K was estimated using SOC, hydraulic conductivity (HC) and soil textural composition––sand (S), silt (Si), and clay (C) contents of soils––as well as SOC did not change with the land use, we ascribed the changes of USLE-K with the land uses to the differences in the HC as strongly affected by the interactions between SOC and contents of S, Si, and C. On an average, the soil of the grassland (USLE-K = 0.161 t ha h ha⁻¹ MJ⁻¹ mm⁻¹) was more erodible than those of the plantation (USLE-K = 0.126 t ha h ha⁻¹ MJ⁻¹ mm⁻¹). Additionally, topographic factors, such as aspect and slope, were statistically effective on spatial distribution of the USLE-K and SOC.     

Some exact solutions of string cosmology with heat flux in Bianchi type III space-time

In this paper, the Einstein field equations have been solved for a cloud of string with heat flux in Bianchi type III space-time. The physical and geometrical properties of the model have been examined.     

Inhomogeneous cylindrically-symmetric models in string cosmology

In this paper, the Einstein field equations have been solved for inhomogeneous cylindrically symmetric space times with string source. Certain physical and geometrical properties of the models have been examined.     

Biosorption of mercury(II), cadmium(II) and lead(II) ions from aqueous system by microalgae Chlamydomonas reinhardtii immobilized in alginate beads

The potential use of the immobilized microalgae (in Ca-alginate) of Chlamydomonas reinhardtii to remove Hg(II), Cd(II) and Pb(II) ions from aqueous solutions was evaluated using bare Ca-alginate bead as a control system. Ca-alginate beads containing immobilized microalgae were incubated for the uniform growth at 22 °C for 5 days. Effects of pH, temperature, initial concentration of metal ions and biosorbent dosages on the adsorption of Hg(II), Cd(II) and Pb(II) ions were studied. Adsorption of Hg(II), Cd(II) and Pb(II) ions on the immobilized microalgae showed highest values at around pH 5.0 to 6.0. The adsorption equilibrium was represented with Langmuir and Freundlich adsorption isotherms. The adsorption of these ions on the immobilized microalgae followed second-order kinetics and equilibrium was established in about 60 min. The temperature change in the range of 5–40 °C did not affect the adsorption capacities of the immobilized microalgae. The immobilized-algal systems can be regenerated using 2 M NaCl for Hg(II), Cd(II) and Pb(II) ions.