Some string cosmological models in Bianchi Type I space-time     

Ilhami Yavuz  Ismail Tarhan 《Astrophysics and Space Science》1996,240(1):45-54

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.  相似文献   

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

A. B. Yavuz 《Environmental Geology》2006,51(2):211-227

?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.  相似文献   

AHP and GIS based land suitability analysis for Cihanbeyli (Turkey) County     

Ayla Bozdağ  Fadim Yavuz  Aslı Süha Günay 《Environmental Earth Sciences》2016,75(9):813

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The investigation of static and dynamic capillary by water absorption in porous building stones under normal and salty water conditions     

Mustafa Yavuz Çelik  Ahmet Uğur Kaçmaz 《Environmental Earth Sciences》2016,75(4):307

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Recurvature dynamics of a typhoon   总被引：1，自引：0，他引：1  

T. N. Krishnamurti  H. S. Bedi  K. S. Yap  D. Oosterhof  G. Rohaly 《Meteorology and Atmospheric Physics》1992,50(1-3):105-126

Summary In this paper we present some recent work on typhoon prediction with a high resolution global model. The emphasis of this paper is on typhoon recurvature. Here we include examples of successful typhoon recurvature track forecasts made from a very high resolution global spectral model. The main objective of this study however is to go beyond the forecasts, i.e. to interrogate the history tapes and to diagnose residue-free budgets of the divergence and vorticity. The premise of this paper is that the recurvature of the typhoons depends on both the usual advection of vorticity by the layer mean winds and the advection of divergence in the outflow layers of the storm.The region immediately outside the heavy rain area of the storm experiences large values of divergent outflows which contribute a significant advection of divergence. Through the Dine's compensation this region must, in consort, experience an enhancement of low level convergence and of deep convection, thus contributing to the storm motion. We distinguish two facets of storm motion and recurvature, one based on the conventional steering that invokes the advection of vorticity by a vertical integrated flow, the other is the generation mechanism proposed here. During recurvature the storm appears to move in a direction which is influenced by the rotational and the divergent flow dynamics. Increased vertical resolution in the outflow layer is shown to resolve stronger amplitudes in the outflow layer divergence and thus to contribute to improved forecasts of recurvature. A number of processes seem to simultaneously evolve, these include the strong advection of divergence part of the wind, enhancement of cumulus convection over this region, an enhancement of lower tropospheric convergence, generation of vorticity of the lower troposphere and the attendant recurvature.With 16 Figures  相似文献   

Meandering valley of Karjan-Terav rivers in district broach,Gujarat     

Naresh Bedi 《Journal of the Indian Society of Remote Sensing》1980,8(2):1-5

Karjan river is an important tributary of Narmada in Gujarat. Along with one of its own tributaries, called Terav it has carved a “meandering valley” across the block faulted rldge and valley Deccan Trap topography, south of Narmada. Karjan originates at Bardipada, which is much nearer to Tapti river than Narmada and in the initial stretches its channel is consequent to faults and fractures. However, before emerging on to the alluvial plain in north it has a sinuous valley. With confines of this valley the present stream channel wanders back and forth and has incised deep into various Deccan Trap flows. The geometry of such meanders shows that this is an symmetric meandering valley. The valley as such is an antecedent one in which the present stream channel is ur.derfit and ingrown. Natural fluvial processes, accelerated by dynamic rejuvenation of the area and wetter climatic phases during Pleistocene and Holocene seem to have carved this meandering valley and integrated the drainage.  相似文献   

Organization of convection and monsoon forecasts     

Prof. Dr. T. N. Krishnamurti  H. S. Bedi  Wei Han 《Meteorology and Atmospheric Physics》1998,67(1-4):117-134

Summary In this paper we address the issue of monsoon forecasts in relation to the organization of convection. Given a physical initialization procedure, within a data assimilation, it is possible to use the detailed distribution of rainfall from mesoconvective precipitating elements to define the initial state of a global model. If that is carried out using a very high resolution model then the initial state can carry within it an organization of convection within the resolvable scales. Then the impact of physical initialization on the maintenance and prediction of tropical weather such as the monsoon can be determined. Lacking such an initialization, one can expect the convectively driven energetics to be biased, and a slow degradation of the forecasts can follow. Several examples of forecasts at different resolutions are discussed here. The main findings of this study are that improved forecast results are obtained when physical initialization is invoked where the observed rain and the model resolution are comparable, i.e. the footprint of the highest resolutions rainfall estimates obtained from satellite based data sets (principally we use the SSM/I instrument over the oceans). At this resolution, we note that the model is able to carry an organization of convection in the initialization and in the forecasts through the medium-range time scale.We have compared our results of monsoon studies at a resolution T255 with those at resolution T62. The transform grid separation at the resolution T255 is approximately 50 km and at the resolution T62, it is approximately 200 km. We find that the model at the higher resolution (T255) performs better and has more realistic energy conversions for the convectively driven synoptic scale monsoon.An organization of convection, at the synoptic scales, is not seen in the forecasts at lower resolutions, T62, where the rainfall patterns are generally much broader and tend to be more zonal. Such organization appears more realistic at the resolution T255. Variances of the energy conversion, calculated in the two-dimensional spectral space, from physically initialized short range forecasts at the higher resolution are seen to be largest on the scales of the monsoon. Similar calculations for the reanalyzed fields at lower resolutions show the spectral distribution of variances to be biased towards local Hadley scale overturnings.With 12 Figures  相似文献   

Mineralogy and major-trace element geochemistry of the Haymana manganese mineralizations,Ankara, Turkey   总被引：2，自引：0，他引：2  

A. Karakuş  B. Yavuz  S. Koç 《Geochemistry International》2010,48(10):1014-1027

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.  相似文献   

Reply to the discussion on “Prediction of ground vibrations resulting from the blasting operations in an open pit mine by adaptive neuro-fuzzy inference system” by Yavuz Karsavran     

Melih Iphar  Mahmut Yavuz  Hakan Ak 《Environmental Earth Sciences》2010,60(6):1343-1345

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Reply to discussion on “Relation between spring-water chemistry and hydrothermal alteration in the Şaplica volcanic rocks, Şebinkarahisar (Giresun,Turkey)” [Journal of Geochemical Exploration, 2007, v. 93, p. 35–46]     

N. Karakaya  M.Ç. Karakaya  M.T. Nalbantçılar  F. Yavuz 《Journal of Geochemical Exploration》2009

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