نتایج جستجو برای: wave velocity
تعداد نتایج: 341742 فیلتر نتایج به سال:
The present paper deals with the generation of Love waves in a layer of finite thickness over an initially stressed heterogeneous semi-infinite media. The rigidity and density of the layer are functions of temperature, i.e. they are temperature dependent. The lower substratum is an initially stressed medium and its rigidity and density vary linearly with the depth. The frequency relation of Lo...
The present paper studies the possibility of propagation of torsional surface waves in an inhomogeneous anisotropic layer lying between two heterogeneous half-spaces (upper and lower half-space). Both the half-spaces are assumed to be under compressive initial stress. The study reveals that under the assumed conditions, a torsional surface wave propagates in the medium. The dispersion relation ...
In this paper, a six-stage interactive model is presented for the perforation of metallic plates using blunt deformable projectiles when plastic wave propagation in both target and projectile is considered. In this analytical model, it is assumed that the projectile and target materials are rigid – plastic linear work hardened. The penetration of the projectile into the target is divided into s...
In tire industry, it is very crucial to evaluate physical and mechanical properties of the rubber which is used for production of the tire, to ensure the quality of the final product. Resilience is an important property of a rubber, which cannot be evaluated through direct measurement in production cycle in this industry. Therefore, non-destructive ultrasonic testing, which has been used in man...
We consider wave packets of free particles with a general energymomentum dispersion relation E(p). The spreading of the wave packet is determined by the velocity v = ∂pE. The position-velocity uncertainty relation ∆x∆v ≥ 1 2 |〈∂2 pE〉| is saturated by minimal uncertainty wave packets Φ(p) = A exp(−αE(p) + βp). In addition to the standard minimal Gaussian wave packets corresponding to the non-rel...
BACKGROUND The role of antiretroviral therapy in acceleration of atherosclerosis in patients with human immunodeficiency virus (HIV) infection is controversial. We hypothesized that aortic stiffness, an early marker of arteriosclerosis, may be increased in HIV patients treated with protease inhibitors. METHODS AND RESULTS In 32 HIV-infected patients treated with protease inhibitors and 32 age...
To establish a versatile means for screening and management of nonalcoholic steatohepatitis (NASH), shear wave velocity was measured in 20 normal controls and 138 consecutive nonalcoholic fatty liver disease (NAFLD) cases. Referencing biochemical properties in 679 healthy volunteers, a formula to distinguish NASH suspects was established and validated in another cohort of 138 histologically pro...
Three-dimensional AE-Tomography computes source locations of AE and reconstructs elastic wave velocity distribution simultaneously from arrival times of AE at receivers. Its algorithm is summarized that elastic wave velocity distribution is updated by using estimated travel times with conventional elastic wave velocity tomography technique. The estimated travel time is obtained as a difference ...
Cold environmental temperatures increase sympathetic nerve activity and blood pressure, and increase the risk of acute cardiovascular events in aged individuals. The acute risk of cardiovascular events increases with aortic pulse wave velocity as well as elevated central and peripheral pulse pressures. The aim of this study was to examine the independent influence of aortic pulse wave velocity ...
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