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  • Non-contact strain sensing of objects by use of single-walled carbon nanotubes
    Patent number: 9255853
    Abstract: In some embodiments, the present invention provides methods of detecting strain associated with an object by: (1) irradiating a composition that has been applied to the object, where the composition comprises semiconducting single-walled carbon nanotubes; (2) measuring an emission from the irradiated composition, where the emission comprises near infrared emission; and (3) correlating the near infrared emission to the presence or absence of strain associated with the object. In some embodiments, the aforementioned steps occur without physically contacting the object or the composition. In some embodiments, the aforementioned steps occur without utilizing Raman spectroscopy. Further embodiments of the present invention also include a step of applying the composition to the object.
    Type: Grant
    Filed: March 14, 2013
    Date of Patent: February 9, 2016
    Assignee: WILLIAM MARSH RICE UNIVERSITY
    Inventors: R. Bruce Weisman, Paul A. Withey, Sergei M. Bachilo, Satish Nagarajaiah, Venkata Srivishnu M. Vemuru
  • NON-CONTACT STRAIN SENSING OF OBJECTS BY USE OF SINGLE-WALLED CARBON NANOTUBES
    Publication number: 20150115159
    Abstract: In some embodiments, the present invention provides methods of detecting strain associated with an object by: (1) irradiating a composition that has been applied to the object, where the composition comprises semiconducting single-walled carbon nanotubes; (2) measuring an emission from the irradiated composition, where the emission comprises near infrared emission; and (3) correlating the near infrared emission to the presence or absence of strain associated with the object. In some embodiments, the aforementioned steps occur without physically contacting the object or the composition. In some embodiments, the aforementioned steps occur without utilizing Raman spectroscopy. Further embodiments of the present invention also include a step of applying the composition to the object.
    Type: Application
    Filed: March 14, 2013
    Publication date: April 30, 2015
    Applicant: William Marsh Rice University
    Inventors: R. Bruce Weisman, Paul A. Withey, Sergei M. Bachilo, Satish Nagarajaiah, Venkata Srivishnu M. Vemuru
  • NEGATIVE STIFFNESS DEVICE AND METHOD
    Publication number: 20130118098
    Abstract: A negative stiffness device and method for seismic protection of a structure is described. In one embodiment, the device has an anchor frame and a movement frame laterally translatable relative to the anchor frame. The anchor frame and movement frame have respective extension portions. A linkage is pivotably connected to the extension portion of the anchor frame. A compressed spring has a first end is attached to the extension portion of the movement frame and a second end attached to the linkage. The compressed spring has a spring force. In a rest state, the compressed spring does not apply a lateral force to the movement frame. In an engaged state, the compressed spring is configured to apply a lateral force to displace the movement frame in a lateral direction of a seismic load. The spring force is amplified by the linkage when the movement frame is laterally displaced to an amplification point.
    Type: Application
    Filed: November 9, 2012
    Publication date: May 16, 2013
    Inventors: Michael C. Constantinou, Andrei M. Reinhorn, Apostolos A. Sarlis, Douglas Taylor, David A. Lee, Satish Nagarajaiah, Dharma Theja R. Pasala
  • Structural vibration damper with continuously variable stiffness
    Patent number: 6098969
    Abstract: A semi-active variable stiffness control (SAIVS) device, which can change its stiffness continuously and smoothly between a maximum and minimum stiffness. It comprises four spring and telescoping tube elements arranged in a rhombus configuration with pivot joints at the vertices. A control rod powered by a DC servomotor reconfigures the aspect ratio of the rhombus under computer control. This aspect ratio determines the stiffness of the device, and is continuously variable using little power. The SAIVS is installed as a connection between structural elements, and varies the connection stiffness smoothly by changing its configuration in response to a control algorithm in the computer. The algorithm obtains accelerometer and displacement input as feedback to optimize the result. Thus it maintains the structure in a non-resonant vibration state under dynamic disturbances such as earthquakes and windstorms.
    Type: Grant
    Filed: August 17, 1998
    Date of Patent: August 8, 2000
    Inventor: Satish Nagarajaiah
  • Smart materials: strain sensing and stress determination by means of nanotube sensing systems, composites, and devices
    Publication number: 20060253942
    Abstract: The present invention is directed toward devices comprising carbon nanotubes that are capable of detecting displacement, impact, stress, and/or strain in materials, methods of making such devices, methods for sensing/detecting/monitoring displacement, impact, stress, and/or strain via carbon nanotubes, and various applications for such methods and devices. The devices and methods of the present invention all rely on mechanically-induced electronic perturbations within the carbon nanotubes to detect and quantify such stress/strain. Such detection and quantification can rely on techniques which include, but are not limited to, electrical conductivity/conductance and/or resistivity/resistance detection/measurements, thermal conductivity detection/measurements, electroluminescence detection/measurements, photoluminescence detection/measurements, and combinations thereof. All such techniques rely on an understanding of how such properties change in response to mechanical stress and/or strain.
    Type: Application
    Filed: January 23, 2004
    Publication date: November 9, 2006
    Applicant: William Marsh Rice University
    Inventors: Enrique Barrera, Satish Nagarajaiah, Prasad Dharap, Li Zhiling, Jong Kim
  • Smart materials: strain sensing and stress determination by means of nanotube sensing systems, composites, and devices
    Patent number: 7730547
    Abstract: The present invention is directed toward devices comprising carbon nanotubes that are capable of detecting displacement, impact, stress, and/or strain in materials, methods of making such devices, methods for sensing/detecting/monitoring displacement, impact, stress, and/or strain via carbon nanotubes, and various applications for such methods and devices. The devices and methods of the present invention all rely on mechanically-induced electronic perturbations within the carbon nanotubes to detect and quantify such stress/strain. Such detection and quantification can rely on techniques which include, but are not limited to, electrical conductivity/conductance and/or resistivity/resistance detection/measurements, thermal conductivity detection/measurements, electroluminescence detection/measurements, photoluminescence detection/measurements, and combinations thereof. All such techniques rely on an understanding of how such properties change in response to mechanical stress and/or strain.
    Type: Grant
    Filed: January 23, 2004
    Date of Patent: June 1, 2010
    Assignee: William Marsh Rice University
    Inventors: Enrique V. Barrera, Satish Nagarajaiah, Prasad Dharap, Li Zhiling, Jong Dae Kim
  • Negative stiffness device and method
    Patent number: 8857110
    Abstract: A negative stiffness device and method for seismic protection of a structure is described. In one embodiment, the device has an anchor frame and a movement frame laterally translatable relative to the anchor frame. The anchor frame and movement frame have respective extension portions. A linkage is pivotably connected to the extension portion of the anchor frame. A compressed spring has a first end is attached to the extension portion of the movement frame and a second end attached to the linkage. The compressed spring has a spring force. In a rest state, the compressed spring does not apply a lateral force to the movement frame. In an engaged state, the compressed spring is configured to apply a lateral force to displace the movement frame in a lateral direction of a seismic load. The spring force is amplified by the linkage when the movement frame is laterally displaced to an amplification point.
    Type: Grant
    Filed: November 9, 2012
    Date of Patent: October 14, 2014
    Assignees: The Research Foundation for The State University of New York, William Marsh Rice University, Taylor Devices, Inc.
    Inventors: Michael C. Constantinou, Andrei M. Reinhorn, Apostolos A. Sarlis, Douglas Taylor, David A. Lee, Satish Nagarajaiah, Dharma Theja R. Pasala
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