A novel self-seeding method for particle image velocimetry measurements of subsonic and supersonic flows.

A self-seeding particle method is proposed for particle image velocimetry measurements in closed cycles such as Organic Rankine Cycles. Condensed droplets of vapor are used as tracers in a closed cycle for both subsonic and supersonic regimes. A free jet of R245fa in the vapor phase is examined in a case study with two different nozzle pressure ratios of 5.

Flow visualization over a thick blunt trailing-edge airfoil with base cavity at low Reynolds numbers using PIV technique.

Abstract: In this study, the effect of cutting the end of a thick airfoil and adding a cavity on its flow pattern is studied experimentally using PIV technique. First, by cutting 30% chord length of the Riso airfoil, a thick blunt trialing-edge airfoil is generated. The velocity field around the original airfoil and the new airfoil is measured by PIV technique and compared with each other.

Retinopathy of Prematurity: Single versus Multiple-Birth Pregnancies.

Purpose: To compare the frequency and severity of retinopathy of prematurity (ROP) among singleton and multiple-birth neonates referred to Farabi Eye Hospital, Tehran- Iran.

Methods: In this retrospective study, records of 99 consecutive neonates from multiplegestation pregnancies including 68 twins, 26 triplets and 5 quadruplets who were screened for ROP from 2002 to 2004 were reviewed. The frequency, severity and risk factors for ROP were determined and compared to a group of singletons who were matched in terms of gender, birth weight (BW), gestational age (GA), oxygen therapy, respiratory distress syndrome, blood transfusion, sepsis and phototherapy.