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.     

Deterioration of the volcanic kerb and pavement stones in a humid environment in the city centre of Izmir, Turkey

?zmir is the third largest city in Turkey and has being the centre of art, culture, tourism and trade activities throughout the 5,000 years of its history. Natural stones brought from different parts of the world have been widely used for construction of the prestigious buildings, monuments and roads etc., in the past in the city. Renovation of the street pavements and public gathering areas in the city centre has been undertaken by the Metropolitan Municipality in 2000 and continued through the year of 2001. These renovation activities have mainly been carried out in the streets running parallel to the sea shore. Volcanic rocks brought from the Central Anatolia Ankara-Gölba?? (andesites) and Kayseri-?ncesu (tuffs) have been used in the renovation works. These rocks have shown extensive deteriorations within 4 years of their usage between 2001 and 2005 under the influence of different environmental factors. In this study, the deteriorations developed in the recently placed volcanic rocks used as kerb and pavement stones in the city centre of ?zmir in the light of their mineralogical, chemical, physical and mechanical properties, used locations and the environmental factors are presented.     

Mineralogy and major-trace element geochemistry of the Haymana manganese mineralizations,Ankara, Turkey

The study area comprises Çayirli, Harapa?illari and Ortabel (ÇHO) districts in the Haymana town 25 km SW of the Ankara city. In this study, geologic setting, mineralogical and geochemical characteristics of manganese mineralizations are examined and their origin is discussed. Data were obtained from field observations, various polished and thin section determinations and chemical analyses of 25 ore samples. Major and trace element analyses were conducted with ICP-ES and ICP-MS methods at ACME Laboratories (Canada). ÇHO manganese ores are found in reddish radiolarites and partly interbedded marls of the Ankara ophiolitic melange of lower Cretaceous-upper Senonian age. In these extremely folded rocks, manganese is observed as band and lenses. All samples are composed of pyrolusite and quartz. Circular pyrolusites around the gangue form a ring texture and radiolarite ores yield spherical sections. In addition, breccia-like texture is observed between pyrolusite and quartz. Geologic setting, mineralogical and textural data indicate an exogene environment. Major and trace element abundances and correlation among them imply that ÇHO mineralizations are of hydrothermal origin and linked to the same source. Evaluation of all these data shows that ÇHO manganese mineralizations are of hydrothermal type sedimentary mineralization and they were deposited in distal part of the source.     

Performance of shape indices and classification schemes for characterising perceptual shape complexity of building footprints in GIS

Shape characterisation is important in many fields dealing with spatial data. For this purpose, numerous shape analysis and recognition methods with different degrees of complexity have so far been developed. Among them, relatively simple indices are widely used in spatial applications, but their performance has not been investigated sufficiently, particularly for building footprints (BFs). Therefore, this article focuses on BF shape characterisation with shape indices and classification schemes in a GIS environment. This study consists of four phases. In the first phase, the criteria for BF shape complexity were identified, and accordingly, benchmark data was constructed by human experts in three shape complexity categories. In the second phase, 18 shape indices were selected from the literature and automatically computed in GIS. The performance of these indices was then statistically assessed with histograms, correlation matrix and boxplots, and consequently four indices were found to be appropriate for further investigation. In the third phase, two new indices (Equivalent Rectangular index and Roughness index) were proposed with the objective to measure some BF shape characteristics more efficiently. The proposed indices also were found to be appropriate with the same statistical assessment procedures. In the final phase, BF shape complexity categories were created with the pairs of six appropriate indices and four choropleth mapping classification schemes (equal intervals, natural break, standard deviation, and custom) in GIS. The performance of the index–scheme pairs was assessed against the benchmark data. The findings demonstrated that both new indices and two of the selected indices (Convexity and Rectangularity) delivered higher performance. The custom classification scheme was found more ideal to reveal absolute shape complexity with the index value ranges derived from the boxplots while the other classification schemes were more appropriate to reveal relative shape complexity.     

Tsunami risk assessment: economic,environmental and social dimensions

Natural Hazards - In this study, we present a novel methodology that may be used to analyze tsunami risk along coastal regions. The application of the proposed methodology is demonstrated for the...