نتایج جستجو برای: wave velocity of near

تعداد نتایج: 21222321  

Shear wave velocity (Vs) data are key information for petrophysical, geophysical and geomechanical studies. Although compressional wave velocity (Vp) measurements exist in almost all wells, shear wave velocity is not recorded for most of elderly wells due to lack of technologic tools. Furthermore, measurement of shear wave velocity is to some extent costly. This study proposes a novel methodolo...

2017
Jongwon Jung Taeseo Ku Jaehun Ahn

Sand improvements using organic agents have shown promising results. Polyacrylamide is one possible organic agent, which has been shown to influence the shear strength, stiffness, soil remediation, and erosion resistance of geomaterials. In this study, we explored the shear wave velocity (S-wave) and water retention curves of unsaturated sands containing polyacrylamide solutions. The shear wave...

انصاری, سپیده , تجلی‌زاده خوب, یاسر , شریفی, فرشاد , فخرزاده , حسین , کامرانی, فرهاد ,

Background: Dementia is a common health problem in the elderly. Studies have shown that levels of pulse wave velocity (PWV) could predict cognitive impairment. The objective of this study was assessment of the relationship between arterial stiffness levels and cognitive status among the older people. Methods: In this cross-sectional study, 60 individuals included 31 women and 29 men aged ≥ 60 ...

Journal: :iranian biomedical journal 0
youcef remram مختار عطاری mokhtar attari noureddine ababou

accurate measurements of physical characteristics of bone are essential for diagnosis, assessment of change following treatment, and therefore, indirectly, for evaluation of new forms of therapy. this is particularly true of osteoporosis and aging skeleton, in which fractures occur easily. methods: in this study an ultrasonic system was set-up and calibrated on plexiglas tubes of variable thick...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تحصیلات تکمیلی علوم پایه زنجان - دانشکده فیزیک 1392

in the first part of this thesis we explored wetting and its dynamics for small droplets. first, we showed how a simple feature of water droplets on a surface, i.e. laplace pressure, can be exploited to build a micropump. we investigated capillary pumping in microchannels both experimentally and numerically. putting two droplets of different sizes at the in/outlet of a microchannel, will ge...

Journal: :فیزیک زمین و فضا 0
ramin nikrouz assistant professor, geology group, urmia university, iran

refractor ambiguities are big problem in seismic refraction method especially in seismic engineering. there can be hidden subsurface geological phenomena such as hidden faults and shear zones which are not simply predicted by the travel-time graph or some geophysical methods. head wave amplitudes are used to show the resolution of refractor ambiguities and the existence of anisotropy in complex...

An axisymmetric jet issued from a sharp edged circular convergent nozzle has been studied experimentally in the near field at Reynolds number 5.3x104  to search the saddle shape behavior of mean velocity and the role of mean static pressure in the jet flow. Due to the vena contracta effect the centerline mean velocity of the jet increases about 4.2% of its exit value and corresponding decrease ...

Mohsen Emdadifard Seyed,Majdedin Mir Mohammad Hosseini

In the present paper, discrete element method (DEM) is used to study wave propagation phenomenon in granular soils. The effect of factors such as coefficient of friction, frequency, normal stiffness and soil gradation on the wave velocity is studied. Using the wall motion based on the sinusoidal function is the method of loading used in this simulation, through which the pressure wave is transf...

Green’s function, an analytical approach in inhomogeneous linear differential equations, is the impulse response, which is applied for deriving the wave equation solution in composite materials mediums. This paper investigates the study of SH wave’s transmission influenced by concentrated point source disturbance in piezomagnetic material resting over heterogeneous half-space. Green function ap...

Journal: :فیزیک زمین و فضا 0
محمد علی ریاحی دانشیار، گروه فیزیک زمین، مؤسسة ژئوفیزیک دانشگاه تهران سیدهاشم طباطبائی استادیار، بخش ژئوتکنیک، مرکز تحقیقات ساختمان و مسکن، علی بیت اللهی استادیار، بخش ژئوتکنیک، مرکز تحقیقات ساختمان و مسکن، عباس قلندرزاده دانشیار، گروه مهندسی عمران، دانشکده فنی دانشگاه تهران مرتضی طالبیان استادیار، پژوهشکده علوم زمین، سازمان زمین شناسی و معدنی، مرتضی فتاحی استادیار، گروه فیزیک زمین، مؤسسة ژئوفیزیک دانشگاه تهران

seismic refraction and downhole survey were employed to study dynamic characteristics of subsurface materials in bam city, southeast of iran. the data acquisition was performed at 160 p and s-wave refraction stations and 15 boreholes in the city. to derive velocity depth sections along these profiles as well as to perform downhole diagrams, seisimager software was used. based on the obtained va...

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