Search results for "Propeller"

Dynamic Modeling, Energy Analysis, and Path Planning of Spherical Robots on Uneven Terrains

2020

Spherical robots are generally comprised of a spherical shell and an internal actuation unit. These robots have a variety of applications ranging from search and rescue to agriculture. Although one of the main advantages of spherical robots is their capability to operate on uneven surfaces, energy analysis and path planning of such systems have been studied only for flat terrains. This work introduces a novel approach to evaluate the dynamic equations, energy consumption, and separation analysis of these robots rolling on uneven terrains. The presented dynamics modeling, separation analysis, and energy analysis allow us to implement path planning algorithms to find an optimal path. One of t…

The Deep Lingual Artery Axial Propeller flap in intraoral reconstructions

2016

Editorial

"Free or Perforator-Pedicled Propeller Flaps in Lower Extremity Reconstruction: Defining the Coverage Failure": Response.

2018

Retrospective Analysis in Lower Limb Reconstruction: Propeller Perforator Flaps versus Free Flaps.

2017

Background Technical advancements and increasing experience in the management of soft tissue defects in lower extremities have led to the evolution of decisional reconstructive algorithms. Both propeller perforator flaps (PPFs) and free flaps (FFs) proved to be useful methods of reconstruction for lower extremities defects, offering alternative reconstructive tools. We present a case series of PPFs and FFs for reconstruction of lower limbs defects, analyzing and comparing treatment and outcomes. Methods Through a retrospective analysis, we report our experience in performing PPFs or FFs for reconstruction of soft tissue defects of the lower extremities, in patients admitted between 2010 an…

The Role of Diffusion-Weighted Magnetic Resonance Imaging in Cholesteatoma Diagnosis and Follow-up: Study With the Diffusion PROPELLER Technique

2012

Abstract Introduction and objectives The diagnosis of cholesteatoma is based on clinical evaluation and computed tomography. New non-echo-planar diffusion-weighted magnetic resonance imaging (MRI) techniques, without intravenous contrast, are capable of differentiating cholesteatoma from inflammatory tissue, cholesterol granuloma and granulation tissues. The technique is very helpful in differential diagnosis of cholesteatoma, mainly after canal wall-up tympanoplasty surgery, to avoid routine second-look surgery in these patients. Congenital cholesteatoma and difficult cases can be detected and correctly diagnosed as well. The aim of this study was to evaluate sensitivity, specificity, posi…

A new mucosal propeller flap (Deep Lingual Artery Axial Propeller): The renaissance of lingual flaps

2015

BACKGROUND: Lingual flaps provide ideal mucosal coverage for intraoral defects but traditionally require two surgical stages. The authors present an axial mucosal propeller flap for single-stage intraoral reconstruction. The flap includes the mucosa of the lateral side of the tongue, islanded on the deep lingual vessels. METHODS: Between 2011 and 2013, 23 patients underwent intraoral mucosal reconstruction with a deep lingual artery axial propeller flap after cancer resection in the cheek (n = 16), floor of the mouth (n = 2), retromolar trigone (n = 2), hard palate (n = 2), and soft palate (n = 1). Mean defect size was 19.5 cm. Preoperative and postoperative intraoral function was evaluated…

The Propeller Flap for Traumatic Distal Lower-Limb Reconstruction: Risk Factors, Pitfalls, and Recommendations.

2019

BACKGROUND Defects in the distal third of the leg are difficult to cover and often require free tissue transfer, even for defects of limited sizes. Propeller flaps have been designed specifically as an alternative to free tissue transfer but at times have been associated with unacceptably high complication rates. We therefore aimed to prospectively assess our own institutional experience with this technique and to define its role in lower-limb reconstruction. METHODS All patients who had been managed with reconstruction of the distal part of the leg with a propeller flap between 2014 and 2017 were included in the study. Demographic, clinical, and follow-up data on the patients and surgical …

A new one-stage method for nose reconstruction: the supratrochlear artery perforator propeller flap.

2012

LETTER TO EDITOR

Adaptive BEM for Low Noise Propeller Design

2009

A potential-based Boundary Element Method is presented for the aerodynamic and acoustic design of propel- lers at on- and off-design point conditions. Using an adaptive method, a family of airfoil sections is selected to produce the required performance (thrust, torque and efficiency versus advance ratio) at different cruise flight levels. Climb condi- tions are also considered in order to check the off-design point performance. Once the available airfoil data have been stored in a database, the code processes the families of airfoils to generate a complete geometry for a propeller of the specified performance with an optimized noise emission. The computational scheme adjusts the blade geom…

The Rotary Aero Engine from 1908 to 1918

2012

The rotary aero engine is a special type of air-cooled radial engine, where the cylinders are arranged like the spokes of a wheel and turn around the crankshaft. The propeller is connected to the cylinders, while the crankshaft is fixed to the frame. The rotary aero engine, developed in 1908, set new standards of power and light weight within the aircraft industry. It was adopted by many pioneer aviators and widely used to set records of endurance, speed and height. Many aero engine manufacturers produced different models and variants of this type of engine, which was extensively used until the end of the First World War. The latest evolution of the rotary engine was the counter-rotary arra…