41 to 50 of 63 Results
Mar 7, 2011
Bar-Cohen, Yoseph; Lih, Shyh-Shiuh; Badescu, Mircea; Bao, Xiaoqi; Sherrit, Stewart; Widholm, Scott; Ostlund, Patrick; Blosiu, Julian, 2011, "High temperature monitoring the height of condensed water in steam pipes", https://hdl.handle.net/2014/41969, SPIE Smart Structures and Materials/NDE Symposium, San Diego, CA, March 7-10, 2011, JPL Open Repository
An in-service health monitoring system is needed for steam pipes to track through their wall the condensation of water. The system is required to measure the height of the condensed water inside the pipe while operating at temperatures that are as high as 250 deg. C. The system n... |
Mar 7, 2011
Bao, Xiaoqi; Badescu, Mircea; Bar-Cohen, Yoseph; Lih, Shyh-Shiuh; Sherrit, Stewart; Chang, Zensheu; Chen, Beck; Widholm, Scott; Ostlund, Patrick, 2011, "Sensor for direct measurement of the boundary shear stress in fluid flow", https://hdl.handle.net/2014/41997, 18th Annual International Symposium on Smart Structures/ NDE, San Diego, California, March 7-10, 2011, JPL Open Repository
The formation of scour patterns at bridge piers is driven by the forces at the boundary of the water flow. In most experimental scour studies, indirect processes have been applied to estimate the shear and normal stress using measured velocity profiles. The estimations are based... |
Mar 7, 2011
Bao, Xiaoqi; Badescu, Mircea; Bar-Cohen, Yoseph; Lih, Shyh-Shiuh; Sherrit, Stewart; Chang, Zensheu; Chen, Beck; Widholm, Scott; Ostlund, Patrick, 2011, "Sensor for direct measurement of the boundary shear stress in fluid flow", https://hdl.handle.net/2014/43464, Proceedings of the Smart Structures Symposium, San Diego, California, March 6-10, 2011., JPL Open Repository
The formation of scour patterns at bridge piers is driven by the forces at the boundary of the water flow. In most experimental scour studies, indirect processes have been applied to estimate the shear and normal stress using measured velocity profiles. The estimations are based... |
Mar 6, 2011
Sherrit, Stewart; Bao, Xiaoqi; Badescu, Mircea; Chang, Zensheu; Geiyer, Daniel; Allen, Phillip; Ostlund, Patrick; Bar-Cohen, Yoseph, 2011, "Planar rotary motor using ultrasonic horns", https://hdl.handle.net/2014/41977, 18th Annual Symposium on Smart Structures and Materials & Nondestructive Evaluation and Health Monitoring, San Diego, CA, March 6-10, 2011., JPL Open Repository
One of the first piezoelectric motor designs with significant rotational speeds was outlined by Barth. This device used extensional piezoelectric elements to produce a time varying force at a distance r from the center of a centrally supported disk. These extensional actuators pr... |
Mar 7, 2010
Badescu, Mircea; Bao, Xiaoqi; Bar-Cohen, Yoseph; Chang, Zensheu; Kerenyi, Kornel; Lih, Shyh-Shiuh; Sherrit, Stewart; Trease, Brian P.; Widholm, Scott, 2010, "Direct measurement sensor of the boundary shear stress in fluid flow", https://hdl.handle.net/2014/44792, 12th SPIE Conference - Electroactive Polymer Actuators and Devices(EAPAD), San Diego, California, March 7-11, 2010, JPL Open Repository
The flow fields and boundary erosion that are associated with scour at bridge piers are very complex. Direct measurement of the boundary shear stress and boundary pressure fluctuations in experimental scour research has always been a challenge and high spatial resolution and fide... |
Mar 7, 2010
Bao, Xiaoqi; Bar-Cohen, Yoseph; Scott, James; Sherrit, Stewart; Widholm, Scott; Badescu, Mircea, 2010, "Ultrasonic/sonic drill for high temperature application", https://hdl.handle.net/2014/44789, 12th SPIE Conference - Electroactive Polymer Actuators and Devices(EAPAD), San Diego, California, March 7-11, 2010, JPL Open Repository
Venus is one of the many significant scientific targets for NASA. New rock sampling tools with the ability to be operated at high temperatures of the order of 460°C are required for surface in-situ sampling/analysis missions. Piezoelectric materials such as LiNbO₃ crystals and Bi... |
Mar 8, 2009
Bao, Xiaoqi; Scott, James; Boudreau, Kate; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea, 2009, "High temperature piezoelectric drill", https://hdl.handle.net/2014/44652, 2009 SPIE Conference on Smart Structures and Materials, San Diego, California, March 8-12, 2009, JPL Open Repository
The current NASA Decadal mission planning effort has identified Venus as a significant scientific target for a surface in-situ sampling/analyzing mission. The Venus environment represents several extremes including high temperature (460°C), high pressure (~9 MPa), and potentially... |
Mar 8, 2009
Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Louyeh, Sahar, 2009, "Transport powder and liquid samples by surface acoustic waves", https://hdl.handle.net/2014/44651, 2009 SPIE Conference on Smart Structures and Materials, San Diego, California, March 8-12, 2009, JPL Open Repository
Sample transport is an important requirement for In-situ analysis of samples in NASA planetary exploration missions. Tests have shown that powders or liquid drops on a surface can be transported by surface acoustic waves (SAW) that are generated on the surface using interdigital... |
Mar 9, 2008
Sherrit, Stewart; Jones, Christopher M.; Aldrich, Jack B.; Blodget, Chad; Bao, Xioaqi; Badescu, Mircea; Bar-Cohen, Yoseph, 2008, "Multilayer piezoelectric stack actuator characterization", https://hdl.handle.net/2014/42131, SPIE Smart Structures and Materials & Nondestructive Evaluation and Health Monitor, San Diego, California, March 6-10, 2008, JPL Open Repository
Future NASA missions are increasingly seeking to use actuators for precision positioning to accuracies of the order of fractions of a nanometer. For this purpose, multilayer piezoelectric stacks are being considered as actuators for driving these precision mechanisms. In this stu... |
Mar 9, 2008
Bao, Xiaoqi; Biederman, Will; Sherrit, Stewart; Badescu, Mircea; Bar-Cohen, Yoseph; Jones, Christopher; Aldrich, Jack; Chang, Zensheu, 2008, "High-power piezoelectric acoustic-electric power feedthru for metal walls", https://hdl.handle.net/2014/44817, 2008 SPIE Conference on Smart Structures and Materials, San Diego, California, March 9-13, 2008, JPL Open Repository
Piezoelectric acoustic-electric power feed-through devices transfer electric power wirelessly through a solid wall by using acoustic waves. This approach allows for the removal of holes through structures. The technology is applicable to power supply for electric equipment inside... |
