The paper aims to develop a novel pitch control system for a large wind turbine driven by a variable-speed pump-controlled hydraulic servo system. To perform practical pitch control experiments, a full-scale test rig of the hydraulic pitch control system for a 2 MW wind turbine’s blade, including a novel pitch control mechanism, a variable-speed pump-controlled hydraulic servo system, a disturb...

A long-stroke, low-speed marine engine is used as the prime mover of a ship. During operation such engines, excessive wear cylinder liners and piston rings frequently occurs. The breakdown or very dangerous for safety vessel, environment, people on board. reliability components an extremely important topic, it influences efficient vessel. Therefore, to prevent undesired events, essential that c...

Classic theories of hearing have considered only a translational component (piston-like component) of the stapes motion as being the effective stimulus for cochlear activation and thus the sensation of hearing. Our previous study (Huber et al., 2008) qualitatively showed that rotational components around the long and short axes of the footplate (rocking-like components) lead to cochlear activat...

This paper uses lumped parameter dynamic equations to model the mass flow, piston dynamics, and control volume behavior inside a free-piston Stirling engine. A new model for a Stirling engine thermal regenerator that incorporates a dynamically changing temperature gradient is presented. The use of graphite as a regenerator matrix material is justified despite its limited background by comparing...

the present work is the successful extension of an improved equation of state (eos) to refrigerant fluids. the objective is the prediction of isothermal and saturated liquid densities of refrigerants. two temperature-independent parameters appearing in the modified eos are closely related to critical point properties of refrigerant fluids. our results showed that, the proposed eos can predict w...

background & objectives: the aim of this study was to compare the effectiveness of two stapes prostheses in hearing improvement of patients undergoing stapes surgery for otosclerosis.   materials & methods: in this retrospective and descriptive study, the charts of 291 stapedectomies performed by one surgeon (first author) from 1997 to 2011 in imam khomeini and apadana hospitals of ahva...

Abstract. We consider the Casimir force acting on a d-dimensional rectangular piston due to massless scalar field with periodic, Dirichlet and Neumann boundary conditions and electromagnetic field with perfect electric conductor and perfect magnetic conductor boundary conditions. The Casimir energy in a rectangular cavity is derived using cut-off method. It is shown that the divergent part of t...

The present study examines the dynamic behavior of a variable displacement wobble plate compressor which makes it possible to control the cooling capacity continuously. The continuous cooling capacity control Is achieved by the complicated motion of the piston, the piston rod, the wobble plate, the rotating journal and the drive shaft. In order to analyze the complicated motion of each moving e...

BACKGROUND A growing number of studies conducted on stapes surgery have suggested that firm and adequate attachment of the prosthesis onto the long process of the incus plays a key role in surgical success. For this reason, a new prosthesis made of Nitinol characterized by "self-crimping" has been developed. Although better postoperative outcomes achieved with a Nitinol piston have been previou...

The main purpose of the preliminary analyses presented in the paper was to compare the behaviour of the combustion engine piston made of different type of materials under thermal load. A thermomechanical FE analysis of the engine piston made of composite material was shown. A selected engine is installed in one of the popular polish tanks. The proposed new material is characterized by a low hys...