DLR Lampoldshausen carried out cold flow tests to study the flow field in a truncated ideal contour nozzle at low nozzle pressure ratios. A convex shaped Mach disk was found for nozzle pressure ratios less than 10 and a slight concave one for nozzle pressure ratios more than 20. Due to boundary layer transition the convex Mach disk is temporary tilted and redirects the flow towards the nozzle w...

Vortex breakdown of swirling, round jet flows is investigated in the compressible, subsonic regime by means of Direct Numerical Simulation (DNS). This is achieved by solving the compressible Navier–Stokes equations on a cylindrical grid using high-order spatial and temporal discretization schemes. The Reynolds number is Re = ρ c w ◦ c R ◦/μ◦c = 5000 and the flow is moderately compressible with ...

In this study, a robotic fish inspired to carangiform swimmers has been developed. The artifact presents new transmission system that employs the magnetic field interaction of permanent magnets ensure waterproofness and prevention from any overload for structure actuating motor. This mechanism converts rotary motion motor into oscillatory motion. Such an oscillating system, along with wire-driv...

A Southwest Electrostatic Sprayers, Inc., nozzle was configured to a Hudson PortaPak backpack. A test was run to compare deposition of BVA no. 13 oil by the electrostatic nozzle to a standard nonelectrostatic nozzle as collected by Teflon slides. Results indicate that 100% greater deposition occurred with the electrostatic nozzle.

Divergent natural selection drives a considerable amount of the phenotypic and genetic variation observed in natural populations. For example, variation in the predator community can generate conflicting selection on behavioral, life-history, morphological, and performance traits. Differences in predator regime can subsequently increase phenotypic and genetic variations in the population and re...

The question of how individuals in a population organize when living in groups arises for systems as different as a swarm of microorganisms or a flock of seagulls. The different patterns for moving collectively involve a wide spectrum of reasons, such as evading predators or optimizing food prospection. Also, the schooling pattern has often been associated with an advantage in terms of energy c...

this experiment was conducted to study the effect of nozzle types and the time of herbicide incorporation in soil on weed control, using split plot design by randomized block design. the main plots were soil and herbicide mixing time and the subplots were nozzle types with three replications. this study was performed in karaj station of seed and plant improvement institute, located 25 km west o...

BACKGROUND The aim of this paper was to study the prevalence and intensity of Anisakids larvae in the long tail tuna fish captured from Iranian shores of Persian Gulf. METHODS Different organs including skin, abdominal cavity, stomach and intestinal contents, stomach sub serous tissues, liver, spleen, gonads and 20 grams of muscles of 100 long tail tuna fish (Thannustonggol) caught from water...