نتایج جستجو برای: wave attenuation

تعداد نتایج: 263909  

Journal: :ماشین های کشاورزی 0
رسول معمار دستجردی سعید مینایی محمد هادی خوش تقاضا

development of ultrasound technique has not been progressing for evaluating the internal quality of fruits as fast as that of processed foods. in this research for quality assessment of pear fruit (shah miveh variety) an ultrasonic measurement system was constructed to transmit and receive the ultrasonic waves. the apparatus included a pulser-receiver, a pair of 75 khz ultrasonic transducers wi...

Journal: :iranian journal of science and technology (sciences) 2007
h hamzehloo

the strong ground motions recorded during the 2002 avaj earthquake have been used to estimates wave attenuation, qβ, and spectral decay parameter, κ, for the avaj region. qβ for shear wave is estimatedas a function of frequency in the range of 0.6- 18 hz. the results show that qβ increases with frequency in theform of qβ=62.7 f 0.9. our estimates are within the estimated range for different par...

Journal: :تحقیقات مهندسی کشاورزی 0
حسن ذکی دیزجی دانش آموخته دکتری مکانیک ماشین های کشاورزی دانشگاه تربیت مدرس سعید مینایی دانشیار گروه مکانیک ماشین های کشاورزی دانشگاه تربیت مدرس تیمور توکلی هشتجین استاد گروه مکانیک ماشین های کشاورزی دانشگاه تربیت مدرس منیژه مختاری دیزجی دانشیار گروه فیزیک پزشکی دانشگاه تربیت مدرس

ultrasonic testing (ut), a nondestructive testing (ndt) method, is under development for quality determination of agricultural products, although it has long been used in the food industry. determination and measurement of product quality are important in modern agricultural research. noninvasive/nondestructive quality determination is a novel aspect of the postharvest process in which paramete...

Journal: مهندسی دریا 2006
Ali Oveisy, Mohsen Soltanpour,

The present paper offers a numerical model which can be applied for the simulation of wave height distribution on a 2-D horizontal soft mud layer. The model is based on mild slope equations and it includes combined wave refraction, diffraction, reflection and breaking. The high energy dissipation of wave height due to the presence of fluid mud layer has also been simulated. Wave height attenuat...

Journal: :journal of solid mechanics 0
r kumar department of mathematics, kurukshetra university kurukshetra-136119, haryana , india p sharma department of mathematics, kurukshetra university kurukshetra-136119, haryana , india

in this paper the propagation of harmonic plane waves in a homogeneous anisotropic magneto-piezothermoelastic diffusive body with fractional order derivative is studied. the governing equations for a homogeneous transversely isotropic body in the context of the theory of thermoelasticity with diffusion given by sherief et al. [1] are considered as a special case. it is found that three types of...

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...

مختاری دیزجی , منیژه, واحد , محمدرضا, گیتی , معصومه,

Background and purpose: Tissue differentiation based on measurement of ultrasonic parameters is an ideal gool. Ïn this study, attenuation coefficent measurement in 10 MHZ ultrasonic wave in breast tissue, begin and maliguant paranchymal tissue at 20oc, 25 oc, 30 oc and 35 oc were measured and analyzed. Materials and methods : Dat a were collected from 57 biopsies and mastectomy specimens,...

P Sharma R Kumar,

In this paper the propagation of harmonic plane waves in a homogeneous anisotropic magneto-piezothermoelastic diffusive body with fractional order derivative is studied. The governing equations for a homogeneous transversely isotropic body in the context of the theory of thermoelasticity with diffusion given by Sherief et al. [1] are considered as a special case. It is found that three types of...

The need to design blast resistant civilian structures has arisen due to aggressor attacks on many civilian structures around the world. Achieving vibration and wave attenuation with locally resonant metamaterials has attracted a great deal of consideration due to their frequency dependent negative effective mass density. In this paper, metaconcrete, a new material with exceptional properties i...

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...

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