The influence of a propeller on the aerodynamic performance of an MAV is investigated using an unstructured overset grid technique. The flow regime of a fixed-wing MAV powered by a propeller contains both incompressible regions due to the low flight speed, as well as compressible flow areas near the propeller-tip region. In order to simulate all speed flow efficiently, a dual-time preconditioni...

The low-density lipoprotein receptor mediates cholesterol homeostasis through endocytosis of lipoproteins. It discharges its ligand in the endosome at pH < 6. In the crystal structure at pH = 5.3, the ligand-binding domain (modules R2 to R7) folds back as an arc over the epidermal growth factor precursor homology domain (the modules A, B, beta propeller, and C). The modules R4 and R5, which are...

A thrust estimation scheme for a marine propeller has been experimentally tested in waves and with a device that simulates the influence of a vessel hull. The scheme is formed by a nonlinear propeller torque observer and a mapping to generate the thrust from the observed torque. The mapping includes the estimation of the advance number. This is utilized to improve the performance when the prope...

The Low Speed Aeroacoustic Wind Tunnel (LSAWT) at NASA Langley Research Center has recently undergone a configuration change. This change incorporates an inlet nozzle extension meant to serve the dual purposes of achieving lower freestream velocities as well as a larger core flow region. The LSAWT, part of the NASA Langley Jet Noise Laboratory, had historically been utilized to simulate realist...

Background Propeller flaps require torsion of the vascular pedicle of up to 180 degrees. Contrary to free flaps, where the relevance of an intact vascular pedicle has been documented, little is known regarding twisted pedicles of propeller flaps. As secondary surgeries requiring undermining of the flap are common in the extremities, knowledge regarding the necessity to protect the pedicle is re...

Alexander Phillips1, Stephen R. Turnock1, Maaten Furlong2 1 School of Engineering Sciences, University of Southampton 2National Oceanography Centre, Southampton Abstract The use of an unsteady Computational Fluid Dynamic analysis of the manoeuvring performance of a self-propelled ship requires a large computational resource that restricts its use as part of a ship design process. A method is pr...

OBJECTIVE This study investigates the application of a modified reversed gradient algorithm to the Propeller-EPI imaging method (periodically rotated overlapping parallel lines with enhanced reconstruction based on echo-planar imaging readout) for corrections of geometric distortions due to the EPI readout. MATERIALS AND METHODS Propeller-EPI acquisition was executed with 360-degree rotationa...

The dominant feature in the acoustic spectrum of a propeller-driven aircraft is the spectral line corresponding to the propeller blade rate that is equal to the product of the propeller shaft rotation rate and the number of blades on the propeller. The frequency of this line, when measured by a stationary observer on the ground, changes with time due to the acoustical Doppler effect. In this pa...

A non-linear mathematical model, for the roll-yaw behaviour of a ship, is used to predict the prevention of capsize of a small ship. The problem was simulated using the digital package SIMULINK. Simulated responses of the ship with simple hydrodynamic fin stabilisers show that capsize could have been prevented by this means in waves up to 7 m in height. Active control using a simple full span c...

PROPELLER MRI (periodically rotated overlapping parallel lines with enhanced reconstruction) provides images with significantly fewer B(0)-related artifacts than echo-planar imaging (EPI), as well as reduced sensitivity to motion compared to conventional multiple-shot fast spin-echo (FSE). However, the minimum imaging time in PROPELLER is markedly longer than in EPI and 50% longer than in conve...