This paper is the first of a three part report on the transient thermal analysis of screw compressors. Knowledge of rotor-to-housing and rotor-to-rotor clearances is a fundamental first step in defining part dimensions that lead to a design with high efficiency and reliability, characteristics which must be balanced as they impose opposite demands on internal clearances. As reliability and perf...

This paper presents the modeling of a four rotor vertical take-off and landing (VTOL) unmanned air vehicle known as the quad rotor aircraft. The paper presents a new model design method for the flight control of an autonomous quad rotor. The paper describes the controller architecture for the quad rotor as well. The dynamic model of the quad-rotor, which is an under actuated aircraft with fixed...

single-phase squirrel cage and three-phase induction electromotors are the most popular electromotors used in industry from long ago. when an induction motor starts with direct connection method, it takes a lot of current from the power supply (several times the nominal current); so, several methods have been devised to start such electromotors. these methods either reduce the voltage of the st...

Unbalance, fatigue crack and rotor-stator rub are the three common and important faults in a rotor-bearing system. They are originally interconnected each other, and their vibration behaviors do often show strong nonlinear and transient characteristic, especially when more than one of them coexist in the system. This article is aimed to study the vibration response of the rotor system in presen...

R. Kruzel, M. Suliga, Czestochowa University of Technology, Czestochowa, Poland Steel tire cord, springs and rope wires belong to the group of metal products from which the low residual stresses are required. In this paper the eff ect of multiple bending of wire on residual stresses of high carbon steel wires has been assessed. It was found that the application of the multi-roller straightening...

OBJECTIVE To evaluate a surgical technique used to straighten and support the crooked middle third of the nose. DESIGN Retrospective review of 41 patients with a markedly crooked nose who underwent correction using extended spreader grafts made from high-density porous polyethylene. Follow-up ranged from 6 months to 2 years. RESULTS Every patient had substantial improvement in the straighte...

A novel technique to generate three-dimensional Euclidean weavings, composed of close-packed, periodic arrays of one-dimensional fibres, is described. Some of these weavings are shown to dilate by simple shape changes of the constituent fibres (such as fibre straightening). The free volume within a chiral cubic example of a dilatant weaving, the ideal conformation of the G(129) weaving related ...

A 2005 TRC report presents imbalance response measurements of a hollow test rotor supported on bump-type gas foil bearings. The top speed of the tests is 25 krpm, the limit of the drive router motor. The 2005 measurements show the gas foil bearings are prone to subsynchronous whirl with amplitudes of motion exacerbated by the imbalance condition of the rotor, i.e. a forced nonlinearity. Present...