41 to 50 of 88 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/2014/43464, 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 7, 2011
Badescu, Mircea; Sherrit, Stewart; Bao, Xiaogi; Bar-Cohen, Yoseph; Chen, Beck, 2011, "Auto-Gopher : a wire-line rotary-hammer ultrasonic drill.", https://hdl.handle.net/2014/41989, ASME 2011 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, San Diego, California, Mary 7-11, 2011., JPL Open Repository
Developing technologies that would enable NASA to sample rock, soil, and ice by coring, drilling or abrading at a significant depth is of great importance for a large number of in-situ exploration missions as well as for earth applications. Proven techniques to sample Mars subsur... |
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 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 6, 2011
Bar-Cohen, Yoseph, 2011, "Directions for development of the field of electroactive polymer (EAP)", https://hdl.handle.net/2014/45031, 2011 SPIE Smart Structures and Materials, San Diego, California, March 6-10, 2011, JPL Open Repository
In last few years, the rate of development and advances in the field of EAP has accelerated significantly and it is increasingly getting closer to the point of finding them used in commercial products. Substantial development has been reported in the understanding of their drive... |
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 7, 2010
Bar-Cohen, Yoseph, 2010, "Refreshable Braille displays using EAP actuators", https://hdl.handle.net/2014/44786, 12th SPIE Conference - Electroactive Polymer Actuators and Devices(EAPAD), San Diego, California, March 7-11, 2010, JPL Open Repository
Refreshable Braille can help visually impaired persons benefit from the growing advances in computer technology. The development of such displays in a full screen form is a great challenge due to the need to pack many actuators in small area without interferences. In recent years... |
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
Sherrit, Stewart; Trebi-Ollennu, Ashitey; Bonitz, Robert; Bar-Cohen, Yoseph; Yen, Jesse T., 2010, "Compact sensitive piezoelectric mass balance for measurement of unconsolidated materials in space", https://hdl.handle.net/2014/44788, 12th SPIE Conference - Electroactive Polymer Actuators and Devices(EAPAD), San Diego, California, March 7-11, 2010, JPL Open Repository
In many in-situ instruments information about the mass of the sample could aid in the interpretation of the data and portioning instruments might require an accurate sizing of the sample mass before dispensing the sample. In addition, on potential sample return missions a method... |
