Fatigue Analysis of an Optimized HAWT Composite Blade

The objective of this work is to study the fatigue behavior of an optimized composite wind turbine blade of a previous research. This work employs methodologies using classical theory, as well as probabilistic and numerical techniques for the study of the wind turbine blade. Rainflow cycle counting technique and Palmgren-Miner’s sum are used to estimate the fatigue service lifetime of the blade. Fatigue analysis for the blade results showed that the service lifetime of the blade until failure is about 17 years for the turbine operating speed of 36 rpm, and about 15.8 years for the operating speed of 47 rpm, which are less than the expected service life of 20 years by 14.7% and 20.9% respectivel

Identification of materials used in a wooden coffin lid covered with composite layers dating back to the Ptolemaic period in Egypt

A wooden coffin lid, of unknown provenance, with ground and colored layers and an ancient textile, was found at the Egyptian Museum basement in Cairo (JE 36806). The information obtained leads to the conclusion that the coffin lid dates back to the Ptolemaic period in Egypt (332-30 BC), whereas the textile does not belong to the coffin lid. Portable x-ray radiography, photography, optical microscopy, reflected light USB microscopy, Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and Raman spectroscopy were used to assess the deterioration and the structure of the coffin lid and to understand how it was made in the necropolis workshop