BACKGROUND The function of esophagus is to move food by peristaltic motion which is the result of the interaction of the tissue forces in the esophageal wall and the hydrodynamic forces in the food bolus. The structure of the esophagus is layered. In this paper, the esophagus is treated as a two-layered structure consisting of an inner collagen-rich submucosa layer and an outer muscle layer. We...

In this paper, size-dependent effects on the vibration behavior of Timoshenko microbeams under pre-stress loading embedded in an elastic foundation, using modified strain gradient theory (MSGT) and surface stress effects, were studied. To consider the surface stress effects, the Gurtin–Murdoch continuum mechanical approach was employed. Using Hamilton’s principle, the governing equations of mot...

The interior structure of the Moon is constrained by its mass, moment of inertia, and k2 and h2 tidal Love numbers. We infer the likely radius, density, and (elastic limit) rigidity of all interior layers by solving the inverse problem using these observational constraints assuming spherical symmetry. Our results do not favor the presence of a low rigidity transition layer between a liquid oute...

A design method of a phononic crystal structure with local effect is introduced, and the mechanism influencing factors (elastic modulus, density, layer thickness) bandgap are analyzed. The finite element used to calculate eigenfrequency. first width accounts for more than 98% frequency below 20 000 Hz. Two kinds materials different wave velocities arranged periodically form two-dimensional stru...

In this study, unconfined compression tests have been conducted to investigate the impacts of copper slag on mechanical characteristics for stabilized cement and un-stabilized soil. Dozens of specimens were prepared at four percentages of cement (i.e. 0%, 2%, 4% and 6%) and five percentages of copper slag (i.e. 0%, 5%, 10%, 15% and 20%) by weight of dry soil. The samples compacted into a cylind...

Crack propagation along one of the interfaces between a thin ductile adhesive layer and the elastic substrates it joins is considered. The layer is taken as being elastic-plastic, and the fracture process of the interface is modeled by a traction-separation law, characterized by the peak separation stress 6 and the work of separation per unit area To. Crack growth resistance curves for mode I l...

Fibrous structures in the vocal fold were studied in 8 adult Japanese monkeys. Their vocal folds were fixed with formalin and longitudinal and cross-sections were prepared. Some of the samples were treated with 10% NaOH to digest cellular components and elastic fibers, and some of them were treated with 90% formic acid to digest cellular components and collagen fibers. Each sample was then fixe...

the main purpose of this study is to introduce a new method for nanofibers by bulk layer production. in the present method the effect of some parameters including take-up velocity, applied voltage, polymer solution concentration on density of produced layers is investigated. the compression characteristic of nanofiber layers produced under optimum electrospinning is also investigated. it was sh...

Thin soft elastic layers serving as joints between relatively rigid bodies may function as sealants, thermal, electrical, or mechanical insulators, bearings, or adhesives. When such a joint is stressed, even though perfect adhesion is maintained, the exposed free meniscus in the thin elastic layer becomes unstable, leading to the formation of spatially periodic digits of air that invade the ela...

Histopathological studies were made on 9 necropsy specimens of ductus arteriosus with hypoplastic left heart syndrome and I with rubella syndrome. A control group of 40 normal specimens were also studied. In the 17th week of gestation, ductus arteriosus was composed of few elastic fibers, a thick continuous internal elastic lamina and a wide hypocellular area. In the 8th month of gestation, the...