Russell A. Wincheski - Williamsburg VA, US Min Namkung - Yorktown VA, US John W. Simpson - Tabb VA, US
Assignee:
The United States of America as represented by the Administrator of the National Aeronautics and Space Administration - Washington DC
International Classification:
G01N027/82
US Classification:
324235, 324240
Abstract:
A giant magnetoresistive flux focusing eddy current device effectively detects deep flaws in thick multilayer conductive materials. The probe uses an excitation coil to induce eddy currents in conducting material perpendicularly oriented to the coil's longitudinal axis. A giant magnetoresistive (GMR) sensor, surrounded by the excitation coil, is used to detect generated fields. Between the excitation coil and GMR sensor is a highly permeable flux focusing lens which magnetically separates the GMR sensor and excitation coil and produces high flux density at the outer edge of the GMR sensor. The use of feedback inside the flux focusing lens enables complete cancellation of the leakage fields at the GMR sensor location and biasing of the GMR sensor to a location of high magnetic field sensitivity. In an alternate embodiment, a permanent magnet is positioned adjacent to the GMR sensor to accomplish the biasing. Experimental results have demonstrated identification of flaws up to 1 cm deep in aluminum alloy structures.
Russell A. Wincheski - Williamsburg VA, US Jan M. Smits - Monument CO, US Jeffrey D. Jordan - Williamsburg VA, US Anthony Neal Watkins - Hampton VA, US JoAnne L. Ingram - Norfolk VA, US
Assignee:
The United States of America as represented by the Administrator of the National Aeronautics and Space Administration - Washington DC
International Classification:
H01L 31/00
US Classification:
2502141, 977954
Abstract:
A light sensor substrate comprises a base made from a semi-conductive material and topped with a layer of an electrically non-conductive material. A first electrode and a plurality of carbon nanotube (CNT)-based conductors are positioned on the layer of electrically non-conductive material with the CNT-based conductors being distributed in a spaced apart fashion about a periphery of the first electrode. Each CNT-based conductor is coupled on one end thereof to the first electrode and extends away from the first electrode to terminate at a second free end. A second or gate electrode is positioned on the non-conductive material layer and is spaced apart from the second free end of each CNT-based conductor. Coupled to the first and second electrode is a device for detecting electron transfer along the CNT-based conductors resulting from light impinging on the CNT-based conductors.
Carbon Nanotube-Based Sensor And Method For Detection Of Crack Growth In A Structure
Jan M. Smits - Monument CO, US Marlen T. Kite - Hayes VA, US Thomas C. Moore - Poquoson VA, US Russell A. Wincheski - Williamsburg VA, US JoAnne L. Ingram - Norfolk VA, US Anthony N. Watkins - Hampton VA, US Phillip A. Williams - Suffolk VA, US
Assignee:
United States of America as represented by the Administrator of the National Aeronautics and Space Administration - Washington DC
International Classification:
G01N 19/08
US Classification:
73799, 73774, 73762, 73763, 73788, 977972
Abstract:
A sensor has a plurality of carbon nanotube (CNT)-based conductors operatively positioned on a substrate. The conductors are arranged side-by-side, such as in a substantially parallel relationship to one another. At least one pair of spaced-apart electrodes is coupled to opposing ends of the conductors. A portion of each of the conductors spanning between each pair of electrodes comprises a plurality of carbon nanotubes arranged end-to-end and substantially aligned along an axis. Because a direct correlation exists between the resistance of a carbon nanotube and its strain, changes experienced by the portion of the structure to which the sensor is coupled induce a corresponding change in the electrical properties of the conductors, thereby enabling detection of crack growth in the structure.
Controlled Deposition And Alignment Of Carbon Nanotubes
Jan M. Smits - Hampton VA, US Russell A. Wincheski - Williamsburg VA, US JoAnne L. Ingram - Norfolk VA, US Anthony Neal Watkins - Hampton VA, US Jeffrey D. Jordan - Williamsburg VA, US
Assignee:
The United States of America as represented by the Administrator of the National Aeronautics and Space Administration - Washington DC
International Classification:
B05D 3/14
US Classification:
427458, 427301, 977842, 977882
Abstract:
A carbon nanotube (CNT) attraction material is deposited on a substrate in the gap region between two electrodes on the substrate. An electric potential is applied to the two electrodes. The CNT attraction material is wetted with a solution defined by a carrier liquid having carbon nanotubes (CNTs) suspended therein. A portion of the CNTs align with the electric field and adhere to The CNT attraction material. The carrier liquid and any CNTs not adhered to the CNT attraction material are then removed.
Method For Predicting And Optimizing System Parameters For Electrospinning System
The United States of America as represented by the Administrator of the National Aeronautics and Space Administration - Washington DC
International Classification:
B29C 47/00
US Classification:
264465, 264408, 264449, 324453, 429 92
Abstract:
An electrospinning system using a spinneret and a counter electrode is first operated for a fixed amount of time at known system and operational parameters to generate a fiber mat having a measured fiber mat width associated therewith. Next, acceleration of the fiberizable material at the spinneret is modeled to determine values of mass, drag, and surface tension associated with the fiberizable material at the spinneret output. The model is then applied in an inversion process to generate predicted values of an electric charge at the spinneret output and an electric field between the spinneret and electrode required to fabricate a selected fiber mat design. The electric charge and electric field are indicative of design values for system and operational parameters needed to fabricate the selected fiber mat design.
Controlled Deposition And Alignment Of Carbon Nanotubes
Jan M. Smits - Littleton CO, US Russell A. Wincheski - Williamsburg VA, US JoAnne L. Patry - Dulles VA, US Anthony Neal Watkins - Hampton VA, US Jeffrey D. Jordan - Williamsburg VA, US
Assignee:
The United States of America as represented by the Administrator of the National Aeronautics and Space Administration - Washington DC
A carbon nanotube (CNT) attraction material is deposited on a substrate in the gap region between two electrodes on the substrate. An electric potential is applied to the two electrodes. The CNT attraction material is wetted with a solution defined by a carrier liquid having carbon nanotubes (CNTs) suspended therein. A portion of the CNTs align with the electric field and adhere to the CNT attraction material. The carrier liquid and any CNTs not adhered to the CNT attraction material are then removed.
Eddy Current System And Method For Crack Detection
An eddy current system and method enables detection of sub-surface damage in a cylindrical object. The invention incorporates a dual frequency, orthogonally wound eddy current probe mounted on a stepper motor-controlled scanning system. The system is designed to inspect for outer surface damage from the interior of the cylindrical object.
Eddy Current Probe For Surface And Sub-Surface Inspection
Russell A. Wincheski - Williamsburg VA, US John W. Simpson - Yorktown VA, US
Assignee:
U.S.A. as represented by the Administrator of the National Aeronautics and Space Administration - Washington DC
International Classification:
G01R 33/12
US Classification:
324239
Abstract:
An eddy current probe includes an excitation coil for coupling to a low-frequency alternating current (AC) source. A magnetoresistive sensor is centrally disposed within and at one end of the excitation coil to thereby define a sensing end of the probe. A tubular flux-focusing lens is disposed between the excitation coil and the magnetoresistive sensor. An excitation wire is spaced apart from the magnetoresistive sensor in a plane that is perpendicular to the sensor's axis of sensitivity and such that, when the sensing end of the eddy current probe is positioned adjacent to the surface of a structure, the excitation wire is disposed between the magnetoresistive sensor and the surface of the structure. The excitation wire is coupled to a high-frequency AC source. The excitation coil and flux-focusing lens can be omitted when only surface inspection is required.