نتایج جستجو برای: gravity

تعداد نتایج: 62883  

Journal: :فیزیک زمین و فضا 0
مهدی گلی دانشکده مهندسی عمران، دانشگاه صنعتی شاهرود

generally, gravity anomaly is the difference between the observed acceleration of earth's gravity and a normal value. topography (all masses above geoid) plays a main role in definition of the gravity anomaly. based on modeling of the effect of topography, there are different models of gravity anomaly such as free-air and bouguer anomaly. the main goal of the bouguer anomaly is removing of...

Journal: :فیزیک زمین و فضا 0
مرتضی عرفانیان نوروززاده دانشگاه تهران وحید ابراهیم زاده اردستانی هیأت علمی بخش گرانی سنجی-مؤسسه ژئوفیزیک دانشگاه تهران

in this paper, a new formula is applied for the calculation of gravity anomalies from a cylinder model representing a geological body. compared to conventional methods, this new development allows the cylinder to be freely oriented in space. 38 gravity forward models are produced each of which anomaly attributes are calculated. then a linear relationship is established between attributes and so...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده علوم پایه 1391

bekenstein and hawking by introducing temperature and every black hole has entropy and using the first law of thermodynamic for black holes showed that this entropy changes with the event horizon surface. bekenstein and hawking entropy equation is valid for the black holes obeying einstein general relativity theory. however, from one side einstein relativity in some cases fails to explain expe...

Journal: :Evolution; international journal of organic evolution 1988
Lawrence G Harshman Ary A Hoffmann Timothy Prout

The effects of density and food on remating were investigated using Drosophila melanogaster. The frequency of remating was unaffected by density for some combinations of fly strains but was reduced at low relative densities for other combinations. Until females had used most of their stored sperm, remating was less likely when food was absent or contact with food was prevented. Food availabilit...

ژورنال: فیزیک زمین و فضا 2018

The time lapse gravity method is a widely used technique to monitor the subsurface density changes in time and space. In hydrocarbon reservoirs, the density variations are due to different factors, such as: substitution of fluids with high density contrast, water influx, gas injection, and the variation in reservoir geomechanical behavior. Considering the monitoring of saturation changes in the...

A. Akbarpour , H. Chiti, H. R. Naseri, M. Khatibinia,

The paper deals with the reliability–based design optimization (RBDO) of concrete gravity dams subjected to earthquake load using subset simulation. The optimization problem is formulated such that the optimal shape of concrete gravity dam described by a number of variables is found by minimizing the total cost of concrete gravity dam for the given target reliability. In order to achieve this p...

R Kakar, S Kakar

The propagation of torsional waves in a prestressed fiber-reinforced half-space under the effect of magnetic field and gravity has been discussed. The problem has been solved analytically using Whittaker function to obtain the exact solution frequency equations. Numerical results for stress, gravity and magnetic field are given and illustrated graphically. Comparisons are made with the results ...

Gravity data inversion is one of the important steps in the interpretation of practical gravity data. The inversion result can be obtained by minimization of the Tikhonov objective function. The determination of an optimal regularization parameter is highly important in the gravity data inversion. In this work, an attempt was made to use the active constrain balancing (ACB) method to select the...

Journal: :فیزیک زمین و فضا 0
خسرو اشرفی وحید اصفهانیان

in the present work properties of rossby and inertia gravity waves are investigated based on proper orthogonal decomposition (pod) functions. the pod functions are constructed using analytical, experimental or numerical data recorded as snapshots. the pod basis can be carried out to make a reduced order model by galerkin projection of governing equations onto these functions. in this paper, the...

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