We report the results of a numerical and theoretical study of buckling in elastic columns containing a line of holes. Buckling is a common failure mode of elastic columns under compression, found over scales ranging from metres in buildings and aircraft to tens of nanometers in DNA. This failure usually occurs through lateral buckling, described for slender columns by Euler's theory. When the c...

For a photon field of size 20x20cm in a telecobalt machine with ‘Source Diaphragm Distance (SDD)’ of 45 cm, DWTC is designed to provide compensation at ‘source skin distance (SSD)’ of 80 cm. A jig stand with 3 acrylic perforated sheets kept together at specified gaps allow required radial divergence of the metal spokes on equally spaced grid. Dose compensator could be fabricated by a tray mount...

Precision nickel printing screens are shown to be very useful as far-infrared bandpass filters. For a range of such regularly perforated sheets, transmission peaks of ~ 0.9 have been observed to lie at frequencies between 60 and 140 cm(-1). We found that this value shows little degradation by cascading several screens, but the overall filter Q value may be increased from 2.7 to a value of ~ 6. ...

Structural manipulation of the two dimensional graphene surface has been of significant interest as a means of tuning the properties of the nanosheets for enhanced performance in various applications. In this report, a straightforward and highly scalable method is presented to prepare bulk quantities of "holey graphenes", which are graphene sheets with holes ranging from a few to tens of nm in ...

This investigation analyzes the cost-benefit ratio of Transformation Field Analysis to compute elastoplastic behavior periodically perforated metal sheets. Evaluation accuracy and computational cost are analyzed by implementing a finite element approach coupled with technique for different meshes orders. Numerical studies employed compare standard Finite Element analysis Additionally, experimen...

Polyglycolic acid (PGA) sheets and fibrin glue adhere firmly and for a long time, are naturally absorbable, and are used in various fields, including endoscopic therapy [1–8]. We report a case of perforation of a duodenal diverticulum that was treated with an endoscopic tissue-shielding method using PGA sheets and fibrin glue. A 58-year-oldmanwas hospitalized in the nephrology department of our...

  Background Recent studies indicate increased serum amylase in children with acute appendicitis. The objective of the current study was to determine the diagnostic accuracy of raised serum amylase level in prediction of perforated appendicitis in children with acute appendicitis. Materials and Methods In this cross-sectional study, 61 children (aged 3 to 15 years) who underwent appendectomy su...