Lessons learned for implementing near-field active control systems to achieve global control of fan noise

2012 ◽  
Vol 131 (4) ◽  
pp. 3379-3379
Author(s):  
Scott D. Sommerfeldt ◽  
Kent L. Gee
Keyword(s):  
Control Systems ◽  
Active Control ◽  
Near Field ◽  
Lessons Learned ◽  
Fan Noise ◽  
Global Control

Active control of fan noise

2008 ◽  
Vol 17 (2) ◽  
pp. 163-169 ◽  
Author(s):  
Nobuhiko Yamasaki ◽  
Hirotoshi Tajima
Keyword(s):  
Active Control ◽  
Fan Noise

Frequency Shaped Semi-Active Control for Magnetorheological Fluid-Based Vibration Control Systems

2013 ◽  
Author(s):  
Young-Tai Choi ◽  
Norman M. Wereley ◽  
Gregory J. Hiemenz
Keyword(s):  
Vibration Control ◽  
Control Systems ◽  
Active Control ◽  
Control Algorithm ◽  
Active Vibration Control ◽  
Control Algorithms ◽  
Model Parameters ◽  
Mr Fluid ◽  
Control Current ◽  
Active Vibration

Novel semi-active vibration controllers are developed in this study for magnetorheological (MR) fluid-based vibration control systems, including: (1) a band-pass frequency shaped semi-active control algorithm, (2) a narrow-band frequency shaped semi-active control algorithm. These semi-active vibration control algorithms designed without resorting to the implementation of an active vibration control algorithms upon which is superposed the energy dissipation constraint. These new Frequency Shaped Semi-active Control (FSSC) algorithms require neither an accurate damper (or actuator) model, nor system identification of damper model parameters for determining control current input. In the design procedure for the FSSC algorithms, the semi-active MR damper is not treated as an active force producing actuator, but rather is treated in the design process as a semi-active dissipative device. The control signal from the FSSC algorithms is a control current, and not a control force as is typically done for active controllers. In this study, two FSSC algorithms are formulated and performance of each is assessed via simulation. Performance of the FSSC vibration controllers is evaluated using a single-degree-of-freedom (DOF) MR fluid-based engine mount system. To better understand the control characteristics and advantages of the two FSSC algorithms, the vibration mitigation performance of a semi-active skyhook control algorithm, which is the classical semi-active controller used in base excitation problems, is compared to the two FSSC algorithms.

Active Control of Fabricating Nanofibrous Wavy/Helical Arrays Using Near-Field Electrospinning

2018 ◽  
Author(s):  
Xiangyu You ◽  
Ping Guo
Keyword(s):  
Active Control ◽  
Process Parameters ◽  
Electric Field Distribution ◽  
Structural Parameters ◽  
Near Field ◽  
Stretchable Electronics ◽  
Time Varying ◽  
Photovoltaic Devices ◽  
Feature Size ◽  
Experimental Process

A novel and simple near-field electrospinning (NFES) method has been developed to fabricate wavy or helical nanofibrous arrays. By alternating the electrostatic signals applied on auxiliary-electrodes (AE), the structural parameters of deposited patterns can be actively controlled. Compared with the traditional electrospinning methods based on the bending and buckling effects or collector movement, the proposed method shows advantages in the controllability, accuracy, and minimal feature size. Forces operating on the electrospinning jet and the time-varying electric field distribution were analyzed to explain the kinematics of the jet. Nanoscale wavy and helical patterns with various structural parameters were fabricated. The effects of experimental process parameters on structural parameters of deposited patterns were analyzed to demonstrate the controllability of our method in fabricating wavy or helical nanofibrous structures. It is envisioned that this method will benefit the applications in the field of photovoltaic devices, sensors, transducers, resonators, and stretchable electronics.

Experience with Chemical Injection and Umbilicals in Pre-Salt Fields

2021 ◽  
Author(s):  
Sidnei Guerreiro Da Silva ◽  
Andre Athayde Gonçalves ◽  
William Albuquerque Da Silva ◽  
Rafael Di Lorenzo Filho
Keyword(s):  
Control Systems ◽  
Deep Water ◽  
Production Systems ◽  
Poor Performance ◽  
Lessons Learned ◽  
Operational Experience ◽  
The Poor ◽  
Design Requirements ◽  
Chemical Products ◽  
Wax Deposits

Abstract The characteristics of Pre-Salt carbonate reservoirs demand downhole chemical injection to prevent scale, asphaltene, and wax deposits, besides the need of H2S scavenger, and MEG, normally injected at Xmas tree (WCT). The poor performance of injection systems installed in Santos Basin, together with production risks associated to the lack of chemical injection, led the project team to re-evaluate design requirements, such as chemical products characteristics, production systems equipments, umbilicals, and chemical injection valves. In addition, umbilical failures are being observed in other deep-water fields, related to subsea control systems functions. This paper focuses on Company operational experience and lessons learned related to umbilicals and downhole chemical injection.

The Effect of Small Structural Changes on Optimized Active Control Systems

1987 ◽  
pp. 250-260
Author(s):  
Raphael T. Haftka ◽  
Zoran N. Martinovic ◽  
William L. Hallauer ◽  
George Schamel
Keyword(s):  
Control Systems ◽  
Active Control ◽  
Structural Changes
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