P roper angulation of the airpolisher handpiece and use of high-velocity evacuation significantly minimize the generation and the liberation of the aerosol particles into the dental environment. 1S16 As can been seen in Figures 1 through 3. the handpiece nozzle should be held 3-4 mm from the tooth surface, The handpiece nozzle should be kept at a 60 0 angle toward the facial and lingual surface...

Supersonic retropropulsion provides an option that can potentially enhance drag characteristics of high mass entry, descent, and landing systems. Preliminary flow field and vehicle aerodynamic characteristics have been found in wind tunnel experiments; however, these only cover specific vehicle configurations and freestream conditions. In order to generate useful aerodynamic data that can be us...

S EPARATION of supersonic flow in a convergent–divergent nozzle is a fundamental fluid phenomenon that affects a large variety of applications, from fuel systems to aircraft engine nozzles. When a supersonic nozzle is operated at pressure ratioswell below its design point, a shock forms inside the nozzle andflowdownstreamof the shock separates from the nozzle walls. Even though flow separation ...

A numerical analysis is carried out to determine the flowfield and starting characteristics of a straight cylindrical supersonic exhaust diffuser of a high-altitude simulation of a high expansion ratio rocket nozzle. The flow field inside the high-altitude facility is analyzed for a conical nozzle of expansion ratio of 25, diffuser inlet-to-nozzle throat area ratio of 28.9, and diffuser length-...

Nanoparticles have attracted more and more attention in the medicinal field. Zein is a biomacromolecule and can be used as a carrier for delivering active ingredients to prepare controlled release drugs. In this article, we presented the preparation of zein nanoparticles by solution-enhanced dispersion by supercritical CO2 (SEDS) approach. Scanning electron microscopy and transmission electron ...

The growth of a boundary layer at the nozzle wall during laminar vortex ring formation by a nozzle flow generator (piston/cylinder arrangement) is analysed theoretically and numerically and used for modelling the formation of real vortex rings. The predictions of the model are in good agreement with previous experimental and numerical results.

Bay laurel is an evergreen, commercially grown and expensive ornamental pot plant, which is susceptible to different pests like aphids, scale and lerp insects, thrips, caterpillars of codling moth and sooty moulds. Recently, caterpillars of the Mediterranean carnation leafroller (Cacoecimorpha pronubana) cause more and more problems. These pests can lead to important financial losses for the gr...

In an attempt to ensure good-quality printouts of our technical reports, from the supplied PDF files, we process to PDF using Acrobat Distiller. We encourage our authors to use outline fonts coupled with embedding of the used subset of all fonts (in either Truetype or Type 1 formats) except for the standard Acrobat typeface families of Times, Helvetica (Arial), Courier and Symbol. In the case o...

Flow exiting a convergent-divergent nozzle operated at o -design conditions exhibits an instability that causes mixing enhancement in the ow itself and can destabilize an adjacent ow. The latter property enables mixing enhancement of an arbitrary jet via parallel injection of a secondary gas ow. In this study we investigated the e ect of mixing enhancement using secondary parallel injection (ME...

Regular in-service inspection is important to verify the integrity of welded nozzle sections in the nuclear industry. Nozzle sections can be susceptible to crack growth due to thermal fatigue and stress corrosion. Early detection of cracks is therefore essential to ensure the continued safe operation of the facilities. In order to reduce the time and cost of such inspections there is a need to ...