Keith Bridger

US Patent:

6491647, Dec 10, 2002

Filed:

Sep 23, 1999

Appl. No.:

09/401762

Inventors:

Keith Bridger - Washington DC
Arthur V. Cooke - Baltimore MD
Philip M. Kuhn - Severna Park MD
Joseph J. Lutian - Arnold MD
Edward J. Passaro - Towson MD
John M. Sewell - Cockeysville MD
Terence V. Waskey - Centerville MD
Gregg R. Rubin - Baltimore MD

Assignee:

Active Signal Technologies, Inc. - Cockeysville MD

International Classification:

A61B 502

US Classification:

600585, 600500, 128900

Abstract:

The present invention relates to a non-invasive device for measuring physiological processes. More particularly, it concerns a device that can be applied externally to the body of an animal or human to detect and quantify displacement, force, motion, vibration and acoustic effects resulting from internal biological functions. Specifically, an inexpensive device is disclosed that is compact, light, portable and comfortable, and operates satisfactorily even with imprecise location on the body, ambient noise, motion and light.

US Patent:

6751954, Jun 22, 2004

Filed:

Nov 4, 2002

Appl. No.:

10/287269

Inventors:

Keith Bridger - Washington DC 20002-6023
Arthur V. Cooke - Baltimore MD 21212
Frank J. Crowne - Laurel MD 20707
Joseph J. Lutian - Arnold MD 21012
John M. Sewell - Cockeysville MD 21030

International Classification:

F16D 3102

US Classification:

60475

Abstract:

A compact hybrid actuator has a fluid pump ( ) arranged to supply fluid to an actuator ( ). The pump has at least one electrically-powered solid-state pump driver ( ) provided with a displacement element ( ). The position of this displacement element modulates the volume of a fluid chamber ( ). A driven valve ( ) is operatively arranged to control the flows of fluid with respect to the pump chamber, and has one member ( ) movable relative to a body ( ) to modulate the opening of ports ( ) so as to form at least one three-way valve. A valve driver ( ) is operatively arranged to operate the driven valve. Electrical power is provided to each valve and to the valve driver so as to operate these various elements in synchronism with one another. The improved pump driver and driven valve may be operated at frequencies in excess of 1 kHz.

US Patent:

6887199, May 3, 2005

Filed:

Mar 12, 2002

Appl. No.:

10/095861

Inventors:

Keith Bridger - Washington DC, US
Arthur V. Cooke - Baltimore MD, US
Philip M. Kuhn - Severna Park MD, US
Joseph J. Lutian - Arnold MD, US
Edward J. Passaro - Towson MD, US
John M. Sewell - Cockeysville MD, US
Terence V. Waskey - Centerville MD, US
Gregg R. Rubin - Baltimore MD, US

Assignee:

Active Signal Technologies, Inc. - Linthicum MD

International Classification:

A61B005/00

US Classification:

600300, 128920, 600544

Abstract:

A non-invasive brain assessment monitor is disclosed. An embodiment of the monitor includes a head-mounted brain sensor which passively senses acoustic signals generated from pulsing blood flow through a patient's brain. A reference sensor may be mounted at another location on the patient's body to sense an arterial pulse, and the signals from the brain sensor and reference sensor may be compared. Another embodiment includes transmitters which generate acoustic signals in the brain which are also detected by the brain sensor. The brain assessment monitor may be used to detect conditions such as head trauma, stroke and hemorrhage.

US Patent:

7697263, Apr 13, 2010

Filed:

Mar 27, 2007

Appl. No.:

11/691837

Inventors:

Keith Bridger - Washington DC, US
Arthur V. Cooke - Baltimore MD, US
Walter Arthur Schulze - Alfred Station NY, US

Assignee:

Active Signal Technologies, Inc. - Linthicum MD
Alfred University - Alfred NY

International Classification:

H01G 4/06

US Classification:

361311, 361313, 3613211, 361312, 3613212, 3613061

Abstract:

A ceramic dielectric composition suitable for preparing capacitors for use in high-temperature service conditions is disclosed. The ceramic material and capacitors made from it exhibit unique and heretofore unrealizable properties including low variation in capacitance with voltage up to high fields, low variation in capacitance with temperature over a broad temperature range, retained high permittivity at temperatures up to 200 C. and beyond, low loss, low field-induced strain and adequate capacitance to retain performance at very low service temperatures. The material is based on sodium bismuth titanate (NBT) with selected additions of substituents and dopants to broaden and flatten its dielectric response, lower loss, lower strain, lower voltage coefficient and increase resistivity.

US Patent:

8265291, Sep 11, 2012

Filed:

Nov 15, 2006

Appl. No.:

11/599833

Inventors:

Keith Bridger - Washington DC, US
Arthur V. Cooke - Baltimore MD, US
Dennis J. Kohlhafer - Ellicott City MD, US
Joseph J. Lutian - Arnold MD, US
John M. Sewell - Glen Rock PA, US
Richard E. Strite - Germantown MD, US

Assignee:

Active Signal Technologies, Inc. - Linthicum MD

International Classification:

A61B 7/04

US Classification:

381 67, 381423, 600586

Abstract:

A physiological sensing stethoscope suitable for use in high-noise environments is disclosed. The stethoscope is designed to be substantially matched to the mechanical impedance of monitored physiological activity and substantially mismatched to the mechanical impedance of air-coupled acoustic activity. One embodiment of the stethoscope utilizes a passive acoustic system. Another embodiment utilizes an active Doppler system. The passive and active systems can be combined in one stethoscope enabling switching from a passive mode to an active mode suitable for use in very high-noise environments. The stethoscope is suitable for use in environments having an ambient background noise of 100 dBA and higher. The passive includes a head having a housing, a flexural disc mounted with the housing, and an electromechanical stack positioned between the housing and the flexural disc in contact with the skin of a patient. The active system detects Doppler shifts using a high-frequency transmitter and receiver.

US Patent:

20120302920, Nov 29, 2012

Filed:

Aug 8, 2012

Appl. No.:

13/569835

Inventors:

Keith Bridger - Washington DC, US
Arthur V. Cooke - Baltimore MD, US
Dennis J. Kohlhafer - Ellicott City MD, US
Joseph J. Lutian - Arnold MD, US
John M. Sewell - Glen Rock PA, US
Richard E. Strite - Germantown MD, US

Assignee:

Active Signal Technologies, Inc. - Linthicum MD

International Classification:

A61B 7/04

US Classification:

600586

Abstract:

A physiological sensing stethoscope suitable for use in high-noise environments is disclosed. The stethoscope is designed to be substantially matched to the mechanical impedance of monitored physiological activity and substantially mismatched to the mechanical impedance of air-coupled acoustic activity. One embodiment of the stethoscope utilizes a passive acoustic system. Another embodiment utilizes an active Doppler system. The passive and active systems can be combined in one stethoscope enabling switching from a passive mode to an active mode suitable for use in very high-noise environments. The stethoscope is suitable for use in environments having an ambient background noise of 100 dBA and higher. The passive includes a head having a housing, a flexural disc mounted with the housing, and an electromechanical stack positioned between the housing and the flexural disc in contact with the skin of a patient. The active system detects Doppler shifts using a high-frequency transmitter and receiver.

US Patent:

49818210, Jan 1, 1991

Filed:

Nov 16, 1988

Appl. No.:

7/271657

Inventors:

James W. Stendera - Baltimore MD
Keith Bridger - Washington DC
Thomas E. Roloson - Eldersburg MD

Assignee:

Martin Marietta Magnesia Specialties Inc. - Hunt Valley MD

International Classification:

C04B 3500

US Classification:

501 94

Abstract:

This invention relates to a phosphorous-containing organic binder compound for refractory ceramics, a process for the preparation of the binder compound, a pre-mixed, ready-to-use refractory/binder material having a long shelf-like, a method of using the pre-mixed refractory material, and a high strength refractory body produced from the pre-mixed refractory material.

US Patent:

53372093, Aug 9, 1994

Filed:

Sep 10, 1992

Appl. No.:

7/943357

Inventors:

Audrey E. Sutherland - Eldersburg MD
Keith Bridger - Washington DC
Eric M. Fiore - Bel Air MD
Julie A. Christodoulou - Baltimore MD
Alex E. Bailey - Hampstead MD
Allan S. Gelb - Baltimore MD

Assignee:

Martin Marietta Corporation - Bethesda MD

International Classification:

H01G 412
C04B 3546

US Classification:

3613215

Abstract:

A dielectric ceramic composition is disclosed comprising lead magnesium niobate and strontium titanate, barium titanate or a combination thereof. Dopants such as Ta, La, Y, Eu, Nd, Sm, Gd, W, Si, Zr and Sb may also be included in the composition. The lead magnesium niobate with strontium titanate and/or barium titanate composition has been found to possess extremely favorable properties such as high dielectric constant, low dielectric loss, high breakdown strength, low field-induced strain, high electrical resistivity and exceptionally high energy storage capacity. A process is also disclosed for the production of dielectric ceramic materials which includes the use of hot isostatic pressing in an oxygen-containing atmosphere. The disclosed dielectric compositions are useful in capacitors for many applications, including medical devices such as defibrillators and pacemakers.