نتایج جستجو برای: waves

تعداد نتایج: 113311  

Journal: :civil engineering infrastructures journal 0
hasan ghasemzadeh assistant professor, k.n. toosi university of technology, civil engineering faculty, tehran, iran amir ali abounouri msc graduate, k.n. toosi university of technology, civil engineering faculty, tehran, iran

stress waves contain useful information about the properties of porous materials; they can be recovered through different non-destructive testing methods such as crosswell, vertical seismic profile, borehole logging as well as sonic tests. in all these methods, it is crucial to assess the effects of frequency on wave attributes including velocity and intrinsic attenuation. the dependency of per...

Journal: :journal of optoelectronical nano structures 0
a abdikian department of physics, malayer university, malayer, iran ghahraman solookinejad department of physics, marvdasht branch, islamic azad university, marvdasht, iran

in this paper, we investigated the corrected plasmon dispersion relation for graphene in presence of a constant magnetic field which it includes a quantum term arising from the collective electron density wave interference effects. by using quantum hydrodynamic plasma model which incorporates the important quantum statistical pressure and electron diffraction force, the longitudinal plasmons ar...

A Chattopadhyay P.K Saroj, S Chaudhary, S.A Sahu

A mathematical model is considered to investigate the behavior of horizontally polarized shear waves (SH-waves) in fluid saturated porous medium sandwiched between heterogeneous half-spaces. Heterogeneity in the upper half-space is due to linear variation of elastic parameters, whereas quadratic variation has been considered for lower half-space. The method of separation of variables and Whitta...

The purpose of this research is to analyze heat waves characteristics in the warm period of the year as a climatic hazard in Iran. In this study, the daily maximum temperature is taken at 44 synoptic stations during the period 1981-2010. These temperature values were used to extract the intensity, frequency and duration of heat waves using percentile thresholds of 90, 95, and 98. The results sh...

B Singh Baljeet Singh,

The analysis of rotational effect on the characteristics of plane waves propagating in a half space of generalized thermo-piezoelectric medium is presented in context of linear theory of thermo-piezoelectricity including Coriolis and centrifugal forces. The governing equations for a rotating generalized thermo-piezoelectric medium are formulated and solved for plane wave solutions to show the p...

H Alaei H Nemati Karimoy M Hosseini Sh Havakhahi Z Daei

Introduction: The nucleus accumbens is involved in various functions ranging from motivation and reward to feeding and drug addiction. Some researchers have also suggested that this region has some roles in consciousness. In the present study, the effect of electrical stimulation and lesion of nucleus accumbens on Electroencephalogram waves (EEG) of addict and non-addict rats was investigated. ...

Azam Rafiei Kurosh Javidan Mohammad Ebrahim Zomorrodian

Head on collision of localized waves in cold and dense hadronic matter with and without shear and bulk viscosities is investigated. Non-relativistic dynamics of propagating waves is studied using the hydrodynamics description of the system and suitable equation of state. It will be shown that the localized waves are described by solutions of the Burgers equation. Simulations show that the propa...

Journal: :فیزیک زمین و فضا 0
عباسعلی علی اکبری بیدختی استاد، گروه فیزیک فضا، مؤسسة ژئوفیزیک دانشگاه تهران سرمد قادر دانشیار، گروه فیزیک فضا، مؤسسة ژئوفیزیک دانشگاه تهران معصومه شاهسواری دانش آموخته کارشناسی ارشد، گروه فیزیک فضا، مؤسسة ژئوفیزیک دانشگاه تهران

geophysical fluids such as atmosphere and ocean often have stable density stratification; hence internal gravity waves are generated and propagated through them which are important in momentum and energy transfer in these media. these waves are also believed to generate layered structures in such media. recently there have been numerous theoretical, experimental and numerical studies on the way...

باسم غیور, ,

Gravitational waves are considered in thermal vacuum state. The amplitude and spectral energy density of gravitational waves are found enhanced in thermal vacuum state compared to its zero temperature counterpart. Therefore, the allowed amount of enhancement depends on the upper bound of WMAP-5 and WMAP-7 for the amplitude and spectral energy density of gravitational waves. The enhancement of ...

Journal: :iranian rehabilitation journal 0
sahel hemmati pediatric neurorehabilitation research center, university of social welfare and rehabilitation sciences, tehran, iran. roshanak vameghi pediatric neurorehabilitation research center, university of social welfare and rehabilitation sciences, koodakyar ave., daneshjoo blvd., evin, tehran, iran. firozeh sajedi evin, university of social welfares and rehabilitation science masoud gharib evin, university of social welfares and rehabilitation science masoume pourmohammadreza-tajrishi pediatric neurorehabilitation research center university of social welfare & rehabilitation sciences tehran-iran robab teymori evin, university of social welfares and rehabilitation science

objectives: autism spectrum disorder (asd) is a group of neurodevelopment syndromes with impairments in social communications and restrictive or repetitive behaviors. neurofeedback is a new method that may regulate neuro and metabolic function in brain. this study is semi-experimental, with pre and post test.  methods: in 26 children with asd, 40 sessions of neurofeedback were done. brain waves...

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