ultraviolet waves, because of their short wavelength, have a high energy and considerable damaging effects on surfaces. protection against ultraviolet radiations is one of the finishing treatments done on surfaces exposed to sunlight. the importance of this issue in relation to human health, due to complications such as skin burns and cancer, is doubled. up to now, different materials such as z...

Conventional endotracheal tubes have high intrinsic resistive properties due to their high outer-to-inner diameter ratio. This has significant disadvantages in the treatment of the small neonatal or pediatric patient as work of breathing increases with decreasing internal radius. Diagnostic and therapeutic procedures, including suctioning, may be very difficult in patients with small endotrache...

in this study, first energy absorption of axial and bending loading is considered. next, thin walled structures under oblique loading are investigated using abaqus computer simulation, where 180 different cases are simulated. simulation results of the thin walled structures under oblique loading were compared with the experimental results of nagel, and good agreement was perceived. simulation r...

Energy absorber systems like metallic dampers for controlling the structural vibrations due to earthquake have witnessed considerable development in the past few decades. Also there are some studies on the energy absorption of thin-walled tubes due to impact load. Thin-walled tubes have a large deformation capacity and are suitable energy absorbers in the structure during an earthquake provided...

The axial crushing of thin-walled tubes has been the subject of extensive research in the past. The existing kinematic models for predicting crushing behavior of axially loaded thin-walled tubes are systematically reviewed and analyzed. The advantages and limitations of each model are discussed. A new chain link model for circular tubes and square tubes is presented and studied in detail. Unlik...

Energy absorber systems like metallic dampers for controlling the structural vibrations due to earthquake have witnessed considerable development in the past few decades. Also there are some studies on the energy absorption of thin-walled tubes due to impact load. Thin-walled tubes have a large deformation capacity and are suitable energy absorbers in the structure during an earthquake provided...

There is a large body of information relating to the ontogeny, development and the vasculature of eudicotyledonous leaves. However, there is less information available concerning the vascular anatomy of monocotyledonous leaves. This is surprising, given that there are two uniquely different phloem systems present in large groups such as grasses and sedges. Monocotyledonous leaves contain margin...

this paper investigates axial compression process of multi-layered tubes with circular cross-section under the axial loading in the quasi-static condition using experimental method. some specimens are prepared in seven different groups, namely; empty carbon/epoxy composite tubes, solid carbon/epoxy composite rods, empty copper tubes, composite tubes with silicon sealant filler, concentrically s...

assessing the behavior of composite structures which are subjected to impact loads is one of the important subjects in the field of mechanical sciences. using thin-walled tubes which collapsed and absorbed the impact energy is a well-known method to prevent damages to the other parts of the structures. in this paper, deformations, crushing length, peak load, mean force and energy absorption cap...