Collimation is widely used for X-ray examinations to reduce the overall radiation exposure to the patient and improve the contrast resolution in the region of interest (ROI), that has been exposed directly to X-rays. It is desirable to detect the region of interest and exclude the unexposed area to optimize the image display. Although we only focus on the X-ray images generated with a rectangul...

Fig, 1,-25-year-old man with parapharyngeal angiofibroma. A, Unenhanced axial CT scan shows a mass (arrows) in parapharyngeal space, with anterior displacement and splaying of pterygoid plates. B, Enhanced coronal CT scan shows an enhancing left-sided parapharyngeal mass (arrows) displacing pharynx toward right. C, Angiogram of left common carotid artery shows a hypervascular mass (arrows) supp...

Abstract In this paper, we give upper and lower bounds on the number of Steiner points required to onstru t a stri tly onvex quadrilateral mesh for a planar point set. In parti ular, we show that 3⌊ 2 ⌋ internal Steiner points are always suÆ ient for a onvex quadrilateral mesh of n points in the plane. Furthermore, for any given n ≥ 4, there are point sets for whi h ⌈ 2 ⌉ − 1 Steiner points are...

This article deals with the finite element modeling and free vibration analysis of functionally graded nanocomposite beams reinforced by randomly oriented straight single-walled carbon nanotubes (SWCNTs). Nanostructural materials can be used to alter mechanical, thermal and electrical properties of polymer-based composite materials, because of their superior properties and perfect atom arrangem...

Using conductive nanocomposites for bipolar plates in fuel cells can improve their performance. Percolation is the mechanism for nanocomposite conductivity. When the volume fraction of fillers in a composite material reaches a critical value, percolation starts to happen. If the composite material has an infinitesize, the probability of conductivity jumps from zero to 100% at the critical volum...

The floor beams of steel buildings, cold-formed steel floor joists in particular, often require large web openings, which may affect their shear capacities. A cost effective way to mitigate the detrimental effects of such openings is to weld/fasten reinforcements. A difficulty associated with an experimental investigation to establish suitable reinforcement schemes for openings in shear zone is...

Abstract The integrated composite wallboard is a new type of prefabricated building enclosure made autoclaved aerated concrete (ALC) and rock wool panel, which can meet the thermal requirements cold areas in China without additional insulation. ALC divided into local four-sided supported plates by vertical horizontal ribs, makes have different sound insulation performance from single uniform ma...

Accumulative roll-bonding process (ARB) is an important severe plastic deformation technique for production of the ultrafine grained, nanostructured and nanocomposite materials in the form of plates and sheets. In the present work, this process used for manufacturing Al/SiO 2 nanocomposites by using Aluminum 1050 alloy sheets and nano sized SiO 2 particles, at ambient temperature. After 8 cycle...