RFIC and MMIC Design and Technology

2001 ◽  
Keyword(s):  
Design And Technology

Ball bearing turbocharger vibration management: application on high speed balancer

2020 ◽  
Vol 21 (6) ◽  
pp. 619
Author(s):  
Kostandin Gjika ◽  
Antoine Costeux ◽  
Gerry LaRue ◽  
John Wilson
Keyword(s):  
Dynamic Behavior ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Ball Bearing ◽  
Squeeze Film ◽  
Design And Technology ◽  
Squeeze Film Damper ◽  
Damping Coefficients ◽  
Bearing Loads ◽  
Stiffness And Damping

Today's modern internal combustion engines are increasingly focused on downsizing, high fuel efficiency and low emissions, which requires appropriate design and technology of turbocharger bearing systems. Automotive turbochargers operate faster and with strong engine excitation; vibration management is becoming a challenge and manufacturers are increasingly focusing on the design of low vibration and high-performance balancing technology. This paper discusses the synchronous vibration management of the ball bearing cartridge turbocharger on high-speed balancer and it is a continuation of papers [1–3]. In a first step, the synchronous rotordynamics behavior is identified. A prediction code is developed to calculate the static and dynamic performance of “ball bearing cartridge-squeeze film damper”. The dynamic behavior of balls is modeled by a spring with stiffness calculated from Tedric Harris formulas and the damping is considered null. The squeeze film damper model is derived from the Osborne Reynolds equation for incompressible and synchronous fluid loading; the stiffness and damping coefficients are calculated assuming that the bearing is infinitely short, and the oil film pressure is modeled as a cavitated π film model. The stiffness and damping coefficients are integrated on a rotordynamics code and the bearing loads are calculated by converging with the bearing eccentricity ratio. In a second step, a finite element structural dynamics model is built for the system “turbocharger housing-high speed balancer fixture” and validated by experimental frequency response functions. In the last step, the rotating dynamic bearing loads on the squeeze film damper are coupled with transfer functions and the vibration on the housings is predicted. The vibration response under single and multi-plane unbalances correlates very well with test data from turbocharger unbalance masters. The prediction model allows a thorough understanding of ball bearing turbocharger vibration on a high speed balancer, thus optimizing the dynamic behavior of the “turbocharger-high speed balancer” structural system for better rotordynamics performance identification and selection of the appropriate balancing process at the development stage of the turbocharger.

The Expanding Role of Echocardiography in Interventional Cardiology

2010 ◽  
Vol 6 (2) ◽  
pp. 71 ◽  
Author(s):  
Lindsay A Smith ◽  
Amit Bhan ◽  
Mark J Monaghan ◽  
◽  
◽  
...  
Keyword(s):  
Interventional Procedures ◽  
Imaging Modality ◽  
Interventional Cardiology ◽  
Design And Technology ◽  
Team Approach ◽  
Medical Problems ◽  
Multidisciplinary Team Approach ◽  
Case Selection ◽  
Optimal Imaging

Echocardiography provides excellent realtime imaging of the heart, making it the imaging modality of choice immediately before, during and after cardiac interventional procedures. It helps to guide case selection and execution of the intervention, evaluates the effects of the intervention and enables early detection of complications. Advances in the design and technology of medical devices and delivery systems, coupled with demand for alternative non-surgical therapies for common medical problems, have led to an increase in the volume, variety and complexity of non-coronary cardiac interventional procedures performed. Many of these procedures require a multidisciplinary team approach and demand optimal imaging to ensure successful outcomes. The aim of this article is to review the expanding role of echocardiography in non-coronary interventional cardiology in adults.

Design and technology of compact high-power converters

2000 ◽  
Author(s):  
Krishna Shenai ◽  
Philip Neudeck ◽  
Gene Schwarze
Keyword(s):  
High Power ◽  
Power Converters ◽  
Design And Technology

Coworker feedback seeking and feedback environment in China: An expectation states theory approach

2019 ◽  
Vol 47 (9) ◽  
pp. 1-10 ◽  
Author(s):  
Zhenxing Gong ◽  
Mengshuang Liu ◽  
Di Xin ◽  
Faheem Gul Gilal ◽  
Kui Yin ◽  
...  
Keyword(s):  
Design And Technology ◽  
Theory Approach ◽  
Feedback Seeking ◽  
Feedback Environment ◽  
Expectation States ◽  
Industrial Enterprises ◽  
Seeking Behavior ◽  
Expectation States Theory ◽  
The Impact ◽  
The Relationship

We empirically explored the impact of feedback seeking, including feedback inquiry and monitoring, on the coworker feedback environment via coworker identification. Participants were 264 employees who worked in research and development, design, and technology sectors of industrial enterprises in China. The results indicated that feedback monitoring, feedback inquiry, and coworker identification were all positively related to the coworker feedback environment after controlling for the effects of demographic variables. Further, coworker identification fully mediated the relationship between feedback inquiry/monitoring and the coworker feedback environment. Our findings expand understanding of the feedback loop by bridging the gap between coworker feedback seeking and the coworker feedback environment. We recommend that coworkers encourage employees' feedback-seeking behavior so that the workplace feedback environment motivates them to ask for the help they need to work independently.

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