Disk precession and quasi-periodic brightness oscillations of V603 Aql in 2001–2002     

V. Suleimanov  I. Bikmaev  K. Belyakov  N. Sakhibullin  G. Zhukov  Z. Aslan  U. Kiziloglu  I. Khamitov 《Astronomy Letters》2004,30(9):615-629

We present the photometric observations of the old nova V603 Aql with the RTT 150 Russian-Turkish telescope during eleven nights of 2001–2002. We show that the star at this time was in a state with positive superhumps and its photometric period of \(0\mathop .\limits^d 144 - 0\mathop .\limits^d 145\) was longer than the orbital period. We found night-to-night variations in the mean brightness of the system that are consistent with disk precession periods of \(3\mathop .\limits^d 3\) and \(3\mathop .\limits^d 0\) in 2001 and 2002, respectively. Analysis of the results and their comparison with the results of other authors using current theoretical models for disk precession lead us to suggest that the change in the disk precession period was caused by a change in the accretion rate in the system. V603 Aql in a state with negative superhumps was found to be brighter than it is in a state with positive superhumps by \(0\mathop .\limits^m 2 - 0\mathop .\limits^m 3\). We hypothesize that the transition between these states could also be caused by a change in the accretion rate. Quasi-periodic oscillations (QPOs) of the brightness with typical time scales of 9–70 min were detected on each observing night. These time scales were found to change from night to night. The detection of QPOs with a period of about 0.05 of the orbital period and its multiples on certain nights provides evidence for the model of QPO generation through accretion-rate modulation by ionization-front oscillations on the surface of the donor star near the inner Lagrangian point.  相似文献   

Heavy metal pollution and acid drainage from the abandoned Balya Pb-Zn sulfide Mine,NW Anatolia,Turkey   总被引：5，自引：0，他引：5  

Atilla?Aykol  Murat?BudakogluEmail author  Mustafa?Kumral  Ali?H.Gultekin  Melih?Turhan  Vildan?Esenli  Fuat?Yavuz  Yuksel?Orgun 《Environmental Geology》2003,45(2):198-208

This study was conducted to determine the effects of the waste-rock dump (WRD) of the underground polymetallic Balya Mine on the Kocacay River and eventually on Lake Manyas in Turkey. Data presented in this paper include geochemical characteristics of various kinds of water (mine, surface and groundwater) and of suspended-particle samples in the vicinity of Balya. The more polluted mine waters have low pH and high conductivity, while high concentrations of Zn, Cd, Mn tend to be found in the dry and wet seasons. High concentrations of Pb, As, Cr, Cu and S appear only in the wet season. The sources of the heavy metal concentration within the Kocacay River are leached waste, surface run off, and overflow from the spillway of the WRD. To minimize the formation of acids and dissolved metal, and for the remediation of the harmful effects of extreme contamination conditions, it is recommended that lime or alkali materials and organic carbon be added to simulate the action of sulfate-reducing bacteria.  相似文献   

Structural and Geomorphological Aspects of the Kat Landslides (Tokat—Turkey) and Susceptibility Mapping by Means of GIS     

Işik Yilmaz  Mustafa Yildirim 《Environmental Geology》2006,50(6):931-931

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Depositional and pedogenic influences on the environmental geology of Holocene Mississippi River floodplain deposits near Ferriday, Louisiana     

Andres Aslan  Whitney J. Autin 《Engineering Geology》1996,45(1-4):417-432

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Conditioning Fractal (fBm/fGn) Porosity and Permeability Fields to Multiwell Pressure Data     

Ayse Donmez Zeybek  Mustafa Onur 《Mathematical Geology》2003,35(5):577-612

Stochastic fractal (fGn and fBm) porosity and permeability fields are conditioned to given variogram, static (or hard), and multiwell pressure data within a Bayesian estimation framework. Because fGn distributions are normal/second-order stationary, it is shown that the Bayesian estimation methods based on the assumption of normal/second-order stationary distributions can be directly used to generate fGn porosity/permeability fields conditional to pressure data. However, because fBm is not second-order stationary, it is shown that such Bayesian estimation methods can be used with implementation of a pseudocovariance approach to generate fBm porosity/permeability fields conditional to multiwell pressure data. In addition, we provide methods to generate unconditional realizations of fBm/fGn fields honoring all variogram parameters. These unconditional realizations can then be conditioned to hard and pressure data observed at wells by using the randomized maximum likelihood method. Synthetic examples generated from one-, two-, and three-dimensional single-phase flow simulators are used to show the applicability of our methodology for generating realizations of fBm/fGn porosity and permeability fields conditioned to well-test pressure data and evaluating the uncertainty in reservoir performance predictions appropriately using these history-matched realizations.  相似文献   

Linking Access and Vulnerability: Perceptions of Irrigation and Flood Management in Pakistan     

Daanish Mustafa 《The Professional geographer》2002,54(1):94-105

This article reports the results of a survey conducted in four villages in central Pakistan regarding people's perceptions about irrigation‐ and flood‐related issues. The article uses the perception studies methodology from the human ecology school to address the political ecology agenda in resource and hazards geography. The log‐linear analysis of the survey data shows that people are knowledgeable about social power differentials and interactions between various social factors in influencing their access to resources and vulnerability to floods. The article further demonstrates that water users and vulnerable populations are much more likely to suggest social explanations than naturalistic or fatalistic explanations for their differential access to irrigation water and vulnerability to flood hazard.  相似文献   

A palaeomagnetic approach to the origin of the Black Sea     

Mustafa Saribudak 《Geophysical Journal International》1989,99(1):247-252

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SOCIAL CONSTRUCTION OF HYDROPOLITICS: THE GEOGRAPHICAL SCALES OF WATER AND SECURITY IN THE INDUS BASIN*   总被引：1，自引：0，他引：1  

Daanish Mustafa 《Geographical review》2007,97(4):484-501

ABSTRACT. The article identifies important themes and future research directions for analyzing water and conflict dynamics at the subnational scale in the Indus Basin. A historical overview of water development in the Indus Basin suggests that the water‐security nexus was always a salient theme in the minds of water developers, even in the nineteenth century. Conflicts over contemporary large‐scale water‐development projects in the Indian and Pakistani parts of the Indus Basin are reviewed. Engineers' single‐minded focus on megaprojects, to the neglect of the wider set of values that societies attach to water resources in the eastern and western Indus Basin are largely to blame for continuing low‐grade conflict in the basin. A review of local‐level conflicts over water supply and sanitation in Karachi and the distribution of irrigation water in Pakistani Punjab illustrates the critical role of governance and differential social power relations in accentuating conflict. The article argues against neo‐Malthusian assumptions about the inevitability of conflict over water because of its future absolute scarcity. Instead, the article seeks to demonstrate that, despite evidence suggesting that international armed conflict over water does not exist, the potential for political instability over domestic water distribution and development issues is real. The question of whether conflict at the subnational scale will culminate in violence will depend on how water‐resources institutions in the basin behave.  相似文献   

Preliminary results of the alignment and Hartmann tests of the AZT-22 telescope     

Z. Aslan  I. F. Bikmaev  É. A. Vitrichenko  R. I. Gumerov  L. A. Dembo  S. F. Kamus  V. Keskin  U. Kiziloglu  M. N. Pavlinsky  L. N. Panteleev  N. A. Sakhibullin  S. O. Selam  R. A. Sunyaev  I. Khamitov  A. L. Yaskovich 《Astronomy Letters》2001,27(6):398-403

The AZT-22 telescope installed in Turkey (Antalia) was aligned and tested on stars by the Hartmann method. The rms normal deviation of an equivalent optical system is 0.040±0.016 µm. The circle of confusion is 0.40±0.04 arcsec in diameter at a 50% energy level.  相似文献   

Seismic performance of elevated steel silos during Van earthquake,October 23, 2011     

Eren Uckan  Bulent Akbas  Jay Shen  Rou Wen  Kenan Turandar  Mustafa Erdik 《Natural Hazards》2015,75(1):265-287

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