Abstract A new structural stiffness model for the compliant structure in foil gas bearings is introduced in the first part of this work. The model investigates the possibility that the flat segment between bumps, in bump foil strip, may deflect laterally and separate from the rigid bearing surface, also it considers the interaction between bumps in the bump foil strip, the friction between the bump foil and the surrounding structure. The validity of the analytical solution was verified through direct comparison with previous numerical and analytical models. In the second part of this work, the introduced bump foil model is used to investigate the static characteristics of Generation II gas foil thrust bearing. The numerical simulations of the coupled fluid-structure interactions revealed that the foil thrust bearings share many features with their rigid bearing counterpart and the results showed clearly that the load carrying capacity of foil thrust bearings increases nonlinearly with the rotation speed and is expected to reach an asymptote as the rotation speed exceeds certain value. The effects of ramp height and interface friction (i.e., friction at bump foil/rigid bearing interface and bump foil/top foil interface) on the static characteristics of Generation II foil thrust bearings are investigated.

Abstract The idea of a curved stabilizer with damping orifices is applied to the high speed rotating flexible optical disk system in order to reduce the disk deflection and the axial run-out of the disk. A track of orifices is drilled along the edge of a curved annular stabilizer. The effects of the diameter and length of each orifice, number of orifices, and radial position of the orifices on the reduction of axial runout of the disk are investigated experimentally together with the effects of the inner radius for the air flow, initial gap height, and rotational speed. The experimental results showed that the curved stabilizer with orifices can reduce the axial run-out of the disk at 10,000 rpm within 0.010 mm over the entire span of the disk.

We modified a previously reported computer-assisted sperm analysis (CASA) plugin for Image-J to enable analyzing motion of sperm cells in microfluidic environments. Microfluidics is increasingly being used in sperm-related applications such as sperm selection, IVF, and sperm motion behavior. Current CASA systems are not capable of analyzing motion of sperm cells in microfluidic devices where both sperm cells and the liquid itself are constantly moving, contrary to the conventional situation of sperm cells moving in a stationary liquid. We resolved this deficiency in the modified plugin reported here and built an image processing pipeline to enhance object detection, which increased CASA accuracy considerably. More importantly, particle tracking was improved and modified to accommodate sperm cells going out of focus for short periods during swimming on the same track. This last feature is particularly important in microfluidics where height of the microchannel is larger than that of CASA custom chambers to avoid channel blockage; this increased height causes sperm cells to frequently come in and out of focus. New parameters were introduced to allow studying new aspects of sperm motion behavior such as rheotaxis and wall tracking. The new plugin was able to detect and analyze motion of human, bull, and chicken sperm. A preliminary study using this tool agreed well with previously reported studies on rheotaxis and wall tracking behavior of sperm.

We modified a previously reported computer-assisted sperm analysis (CASA) plugin for Image-J to enable analyzing motion of sperm cells in microfluidic environments. Microfluidics is increasingly being used in sperm-related applications such as sperm selection, IVF, and sperm motion behavior. Current CASA systems are not capable of analyzing motion of sperm cells in microfluidic devices where both sperm cells and the liquid itself are constantly moving, contrary to the conventional situation of sperm cells moving in a stationary liquid. We resolved this deficiency in the modified plugin reported here and built an image processing pipeline to enhance object detection, which increased CASA accuracy considerably. More importantly, particle tracking was improved and modified to accommodate sperm cells going out of focus for short periods during swimming on the same track. This last feature is particularly important in microfluidics where height of the microchannel is larger than that of CASA custom chambers to avoid channel blockage; this increased height causes sperm cells to frequently come in and out of focus. New parameters were introduced to allow studying new aspects of sperm motion behavior such as rheotaxis and wall tracking. The new plugin was able to detect and analyze motion of human, bull, and chicken sperm. A preliminary study using this tool agreed well with previously reported studies on rheotaxis and wall tracking behavior of sperm.

Wind is one of the most distinguished renewable sources of energy. Wind Energy Conversion System (WECS) is based on a variable speed wind turbine with direct driven Permanent Magnet Synchronous Generator (PMSG). WECS transmits its electrical power to an AC grid using advanced power electronic converter system. The modelling and operation of a grid connected wind generation system based on a gearless PMSG is being studied. Implementation of the machine side converter control strategy develop a maximum power point tracking (MPPT) method using direct driven PMSG. The grid side converter is used to control active and reactive powers injected into the grid and maintaining the dc link voltage constant.The PMSG is connected to the grid by means of a fully controlled back-to-back converter with a voltage source inverter (VSI) which consists of a pulse width modulation (PWM) and an intermediate DC link circuit. DC-Link Over-Voltage protection Scheme is used to protect the system under fault conditions. The effect of change wind speed and faults on the operation is being studied in this paper. The modeling of wind power generation system with PMSG and power electronic converter interface along with the control scheme is implemented using a MATLAB/SIMULINK simulation package.

Wind is one of the most distinguished renewable sources of energy. Wind Energy Conversion System (WECS) is based on a variable speed wind turbine with direct driven Permanent Magnet Synchronous Generator (PMSG). WECS transmits its electrical power to an AC grid using advanced power electronic converter system. The modelling and operation of a grid connected wind generation system based on a gearless PMSG is being studied. Implementation of the machine side converter control strategy develop a maximum power point tracking (MPPT) method using direct driven PMSG. The grid side converter is used to control active and reactive powers injected into the grid and maintaining the dc link voltage constant.The PMSG is connected to the grid by means of a fully controlled back-to-back converter with a voltage source inverter (VSI) which consists of a pulse width modulation (PWM) and an intermediate DC link circuit. DC-Link Over-Voltage protection Scheme is used to protect the system under fault conditions. The effect of change wind speed and faults on the operation is being studied in this paper. The modeling of wind power generation system with PMSG and power electronic converter interface along with the control scheme is implemented using a MATLAB/SIMULINK simulation package.

Wind is one of the most distinguished renewable sources of energy. Wind Energy Conversion System (WECS) is based on a variable speed wind turbine with direct driven Permanent Magnet Synchronous Generator (PMSG). WECS transmits its electrical power to an AC grid using advanced power electronic converter system. The modelling and operation of a grid connected wind generation system based on a gearless PMSG is being studied. Implementation of the machine side converter control strategy develop a maximum power point tracking (MPPT) method using direct driven PMSG. The grid side converter is used to control active and reactive powers injected into the grid and maintaining the dc link voltage constant.The PMSG is connected to the grid by means of a fully controlled back-to-back converter with a voltage source inverter (VSI) which consists of a pulse width modulation (PWM) and an intermediate DC link circuit. DC-Link Over-Voltage protection Scheme is used to protect the system under fault conditions. The effect of change wind speed and faults on the operation is being studied in this paper. The modeling of wind power generation system with PMSG and power electronic converter interface along with the control scheme is implemented using a MATLAB/SIMULINK simulation package.

Wind is one of the most distinguished renewable sources of energy. Wind Energy Conversion System (WECS) is based on a variable speed wind turbine with direct driven Permanent Magnet Synchronous Generator (PMSG). WECS transmits its electrical power to an AC grid using advanced power electronic converter system. The modelling and operation of a grid connected wind generation system based on a gearless PMSG is being studied. Implementation of the machine side converter control strategy develop a maximum power point tracking (MPPT) method using direct driven PMSG. The grid side converter is used to control active and reactive powers injected into the grid and maintaining the dc link voltage constant.The PMSG is connected to the grid by means of a fully controlled back-to-back converter with a voltage source inverter (VSI) which consists of a pulse width modulation (PWM) and an intermediate DC link circuit. DC-Link Over-Voltage protection Scheme is used to protect the system under fault conditions. The effect of change wind speed and faults on the operation is being studied in this paper. The modeling of wind power generation system with PMSG and power electronic converter interface along with the control scheme is implemented using a MATLAB/SIMULINK simulation package.

This paper proposes the configuration of a wind turbine generating system equipped with permanent magnet synchronous generator (PMSG). There are different types of synchronous generators, but the PMSG is chosen in order to obtain its model. It offers better performance due to higher efficiency and less maintenance since it does not have rotor current and can be used without a gearbox, which also implies a reduction of the weight of the nacelle and a reduction of costs. Wind turbine and drive train have been modelled and the equations that explain their behaviour have been introduced. The generator model is established in the dq – synchronous rotating reference frame. The PMSG is operating in stand-alone which is loaded with different types of loads. The proposed system has been implemented in MATLAB /SIMULINK software.

This paper proposes the configuration of a wind turbine generating system equipped with permanent magnet synchronous generator (PMSG). There are different types of synchronous generators, but the PMSG is chosen in order to obtain its model. It offers better performance due to higher efficiency and less maintenance since it does not have rotor current and can be used without a gearbox, which also implies a reduction of the weight of the nacelle and a reduction of costs. Wind turbine and drive train have been modelled and the equations that explain their behaviour have been introduced. The generator model is established in the dq – synchronous rotating reference frame. The PMSG is operating in stand-alone which is loaded with different types of loads. The proposed system has been implemented in MATLAB /SIMULINK software.