Centrifugal compressors produce high pressure ratio and rotate at speeds. So, a tiny unbalance can produce severe vibration. In this paper, effects of impeller gap on rotor vibration in a high speed centrifugal compressor is investigated. For this purpose, a numerical and experimental analysis are carried out. The moving reference frame method in FLUENT software is used for modeling of geometri...

Abstruct In this paper field-oriented control of a doubly-fed wound rotor induction machine without shaft position sensors is presented. The stator is directly connected to the constant frequency three phase grid and the rotor currents are appropriately controlled to vary the slip power thereby enabling variable speed constant frequency operation. Instead of using dynamic angle controllers for ...

BACKGROUND Ipsilateral femoral neck and shaft fractures are rare, and currently available treatment methods each have their own benefits and limitations. Although reconstruction intramedullary nails have been considered to be effective alternative, clinical outcomes vary significantly in reports. METHODS Thirty-seven consecutive adult patients with 37 combined fractures were treated with reco...

Controlled induction motor drives without mechanical speed sensors at the motor shaft have the attractions of low cost and high reliability. To replace the sensor, the information on the rotor speed is extracted from measured stator voltages and currents at the motor terminals. Vector controlled drives require estimating the magnitude and spatial orientation of the fundamental magnetic flux wav...

Hair dysplasias are congenital or acquired alterations which often involve the hair shaft. Hair shaft abnormalities are characterized by changes in color, density, length and structure. Hair shaft alterations often result from structural changes within the hair fibers and cuticles which may lead to brittle and uncombable hair. The hair of patients with hair shaft diseases feels dry and looks lu...

As part of the demonstration of compliance with federal regulations, a shaft seal system has been designed for the Waste Isolation Pilot Plant. The system completely fills the 650-m shafts with components consisting of the common engineering materials, each of which possesses low permeability, longevity, and can be constructed using available technology. Design investigations couple rock mechan...

Gas injection volume is the key parameter of air drilling with raise boring machine, and determination minimum gas one technologies to improve speed shorten period. Based on characteristics technology, construction technique as circulating medium studied, double-channel structural direct circulation system are discussed. On basis summarizing analyzing principle calculation methods, required for...

The Stirling cycle and related terminology is defined. Selected contemporary research involving the cycle in environmentally friendly applications is cited. Three conventional engine configurations that utilize a reciprocating power piston and crank shaft (the Alpha, Beta, and Gamma) are characterized, in terms of minimum number of components, advantages, and disadvantages. A new type of Stirli...

INTRODUCTION Nonunion following surgical stabilization of humeral shaft fractures, although infrequent, remains a challenge as limited surgical options are available. The difficulties in re-fixation are due to osteolysis produced by the loose implant components and disuse osteopenia of the entire bone segment. We share our experience in the management of a long standing diaphyseal nonunion of h...