Andrew P Washabaugh

US Patent:

6380747, Apr 30, 2002

Filed:

May 12, 1999

Appl. No.:

09/310507

Inventors:

Neil J. Goldfine - Newton MA
Markus Zahn - Lexington MA
Alexander V. Mamishev - Cambridge MA
Darrell E. Schlicker - Watertown MA
Andrew P. Washabaugh - Menlo Park CA

Assignee:

Jentek Sensors, Inc. - Waltham MA

International Classification:

G01R 2908

US Classification:

324457, 324235, 324238, 324671, 324688

Abstract:

A method is disclosed for processing, optimization, calibration, and display of measured dielectrometry signals. A property estimator is coupled by way of instrumentation to an electrode structure and translates sensed electromagnetic responses into estimates of one or more preselected properties or dimensions of the material, such as dielectric permittivity and ohmic conductivity, layer thickness, or other physical properties that affect dielectric properties, or presence of other lossy dielectric or metallic objects. A dielectrometry sensor is disclosed which can be connected in various ways to have different effective penetration depths of electric fields but with all configurations having the same air-gap, fluid gap, or shim lift-off height, thereby greatly improving the performance of the property estimators by decreasing the number of unknowns. The sensor geometry consist of a periodic structure with, at any one time, a single sensing element that provides for multiple wavelength within the same sensor footprint.

US Patent:

6486673, Nov 26, 2002

Filed:

Jan 20, 2000

Appl. No.:

09/488241

Inventors:

Neil J. Goldfine - Newton MA
Darrell E. Schlicker - Watertown MA
Markus Zahn - Lexington MA
Wayne D. Ryan - Pembroke MA
Yanko Sheiretov - Cambridge MA
Andrew Washabaugh - Menlo Park CA

Assignee:

Jentek Sensors, Inc. - Waltham MA

International Classification:

G01R 2726

US Classification:

324326, 324658, 324688

Abstract:

A dielectrometer with a sensor face that carries an excitation electrode driven with a varying voltage. At least two sensing electrodes and a guard electrode are also carried by the sensor face. The sensing electrodes are adapted for single or multiple penetration depth measurements into a test material. The guard electrode surrounds the sensing electrodes and is at about the same voltage as the sensing electrodes.

US Patent:

6657429, Dec 2, 2003

Filed:

Sep 20, 2000

Appl. No.:

09/666879

Inventors:

Neil J. Goldfine - Newton MA
Darrell E. Schlicker - Watertown MA
Andrew P. Washabaugh - Chula Vista CA
Vladimir A. Zilberstein - Chestnut Hill MA

Assignee:

JENTEK Sensors, Inc. - Waltham MA

International Classification:

G01R 3312

US Classification:

324232, 324209, 324227, 324242, 324243

Abstract:

Inductive sensors measure the near surface properties of conducting magnetic materials. The sensors generally include parallel winding segments to induce a spatially periodic magnetic field in a material under test. The sensors may provide a directionally dependent measure with measurements made in varying orientations of the sensor with respect to the material property variation directions. The sensors may be thin, conformable sensors that can be mounted on a test material and, for example, monitor crack initiation under the sensor. A second sensor may be left in air to provide a reference measurement, or the temperature of the material under test can be varied to verify the response of the individual sensing elements. Sensors can be mounted to materials under test in order to not modify the environment that is causing the stress being monitored. A sensor may be flexible to conform to the shape of the surface of the material under test and may be mounted in difficult to access locations such as around fasteners of an aircraft.

US Patent:

6727691, Apr 27, 2004

Filed:

Jan 15, 2002

Appl. No.:

10/046925

Inventors:

Neil J. Goldfine - Newton MA
Vladimir A. Zilberstein - Chestnut Hill MA
Darrell E. Schlicker - Watertown MA
David C. Grundy - Reading MA
Ian Shay - Cambridge MA
Andrew P. Washabaugh - Chula Vista CA

Assignee:

Jentek Sensors, Inc. - Waltham MA

International Classification:

G01B 3312

US Classification:

324240, 324226, 324242, 228102

Abstract:

A sensor that characterizes welds in materials. The sensor includes a meandering drive winding with at least three extended portions and at least one sensing element placed between an adjacent pair of extended portions. A time varying electric current is passed through the extended portions to form a magnetic field. The sensor is placed in proximity to the test material and translated over the weld region. An electrical property of the weld region is measured for each sensing element location. The weld quality is determined using a feature of the electrical property measurement and location.

US Patent:

6781387, Aug 24, 2004

Filed:

Aug 20, 2002

Appl. No.:

10/225406

Inventors:

Neil J. Goldfine - Newton MA
Darrell E. Schlicker - Watertown MA
Markus Zahn - Lexington MA
Wayne D. Ryan - Pembroke MA
Ian C. Shay - Cambridge MA
Andrew Washabaugh - Menlo Park CA

Assignee:

Jentek Sensors, Inc. - Waltham MA

International Classification:

G01R 2726

US Classification:

324658, 324663, 324 711

Abstract:

Described is an inspection method for detecting defects in dielectic test materials using a penetrant material and a dielectric sensor. The penetrant material provides differing dielectric properties from test material and improves the dielectric contrast between defects substantially filled by the penetrant and the test material. The penetrant can be a liquid, such as water, or a powder, as long as it provides a substantially different complex permittivity than the test material.

US Patent:

6784662, Aug 31, 2004

Filed:

Mar 19, 2002

Appl. No.:

10/102620

Inventors:

Darrell E. Schlicker - Watertown MA
Neil J. Goldfine - Newton MA
Andrew P. Washabaugh - Chula Vista CA
Karen E. Walrath - Arlington MA
Ian C. Shay - Cambridge MA
David C. Grundy - Reading MA
Mark Windoloski - Burlington MA

Assignee:

Jentek Sensors, Inc. - Waltham MA

International Classification:

G01N 2772

US Classification:

324242, 324239, 324243

Abstract:

An apparatus for the nondestructive measurements of materials. Eddy current sensing arrays are described which provide a capability for high resolution imaging of test materials and also a high probabilitity of detection for defects. These arrays incorporate layouts for the sensing elements which take advantage of microfabrication manufacturing capabilities for creating essentially identical sensor arrays, aligning sensing elements in proximity to the drive elements, and laying out conductive pathways that promote cancellation of undesired magnetic flux.

US Patent:

6798198, Sep 28, 2004

Filed:

Jan 21, 2003

Appl. No.:

10/348339

Inventors:

Vladimir Tsukernik - West Roxbury MA
Neil J. Goldfine - Newton MA
Andrew P. Washabaugh - Chula Vista CA
Darrell E. Schlicker - Watertown MA
Karen E. Walrath - Arlington MA
Eric Hill - Watertown MA
Vladimir A. Zilberstein - Chestnut Hill MA

Assignee:

JENTEK Sensors, Inc. - Waltham MA

International Classification:

G01N 2782

US Classification:

324262, 324261, 324238, 324220, 324242, 324219

Abstract:

Pressurized elastic support structures or balloons are used to press flexible sensors against the surface a material under test. Rigid support elements can also be incorporated into the inspection devices to maintain the basic shape of the inspection structure and to facilitate positioning of the sensors near the test material surface. The rigid supports can have the approximate shape of the test material surface or the pressurization of one or more balloons can be used to conform the sensor to the shape of the test material surface.

US Patent:

6952095, Oct 4, 2005

Filed:

Sep 20, 2000

Appl. No.:

09/666524

Inventors:

Neil J. Goldfine - Newton MA, US
Darrell E. Schlicker - Watertown MA, US
Andrew P. Washabaugh - Chula Vista CA, US
Vladimir A. Zilberstein - Chestnut Hill MA, US
Vladimir Tsukernik - West Roxbury MA, US

Assignee:

JENTEK Sensors, Inc. - Waltham MA

International Classification:

G01N027/82
G01N027/72
G01R033/12

US Classification:

324240, 324242, 324243, 324202

Abstract:

Inductive sensors measure the near surface properties of conducting and magnetic material. A sensor may have primary windings with parallel extended winding segments to impose a spatially periodic magnetic field in a test material. Those extended portions may be formed by adjacent portions of individual drive coils. Sensing elements provided every other half wavelength may be connected together in series while the sensing elements in adjacent half wavelengths are spatially offset. Certain sensors include circular segments which create a circularly symmetric magnetic field that is periodic in the radial direction. Such sensors are particularly adapted to surround fasteners to detect cracks and can be mounted beneath a fastener head. In another sensor, sensing windings are offset along the length of parallel winding segments to provide material measurements over different locations when the circuit is scanned over the test material. The distance from the sensing elements to the ends of the primary winding may be kept constant as the offset space in between sensing elements is varied.