Active Signal Technologies, Inc.

Martin Marietta Corporation

Martin Marietta Magnesia Specialties, Inc.

Other

Avx Corporation

Alfred University

Keith Bridger

Arthur V Cooke

John M Sewell

Joseph J Lutian

Philip M Kuhn

Edward J Passaro

Frank J Crowne

Stephen R Winzer

Dennis John Kohlhafer

James W Stendera

Terence V Waskey

Richard E Strite

Gregg R Rubin

Andrew Paul Ritter

Alex E Bailey

Allan S Gelb

George L Small

Paul J Caldwell

Ralph Matalon

Audrey E Sutherland

Walter Arthur Schulze

Lorianne Jones

Thomas E Roloson

Francis W Henry

Eric M Fiore

Julie A Christodoulou

Clement P Stoney, Iii

Tushar K Shah

Natarajan Shankar

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.

High sensitivity noise immune stethoscope

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&#xb0; 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.

High-temperature dielectric materials and capacitors made therefrom

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.

Brain assessment monitor

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.

Compact hybrid actuator

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.

Physiological sensing device

A non-invasive apparatus and method are disclosed for measuring intracranial pressure. The intracranial measurement system transmits acoustic signals through a cranium and provides an indication of intracranial pressure based on the received acoustic signals after interaction with the brain. Properties such as acoustic transmission impedance, resonant frequency, resonance characteristics, velocity of sound and the like may be measured and correlated with intracranial pressure. The acoustic signals have typical frequencies of less than 100 kHz, for example, in the audible and sub-audible frequency ranges. The intensity of the transmitted acoustic signals used to determine intracranial pressure is relatively low, resulting in little or no health risks during short term or long term monitoring.

Apparatus and method for measurement of intracranial pressure with lower

An improved transducer array includes a two-dimensional array of multilayer actuators, capable of producing very high displacement with low input voltage, integrally packaged with conditioning electronics. Preferred microcomposite actuators use multiple layers of stacked electrostrictive ceramics and conductive materials. The actuators are aligned in a two-dimensional array and can be integrated with the conditioning electronics in a variety of packaging systems. A preferred packaging system is a flexible high density interconnected multi-chip module which has the integrated circuit chips disposed in a substrate, interconnection layers disposed thereon and the multilayer composite actuators disposed on the surface of the interconnection structure. The actuators in this packaged array may be optionally addressed individually or in blocks, depending on the application intended.

Integrated composite acoustic transducer array

A composition that when added to a dry material that is subsequently compacted, decreases the porosity of the resultant compacted material while improving the density and strength of the compacted material. The substantially dry composition comprises refractory aggregate coated with an organic compound. Preferably the coated aggregate has a size wherein at least 50% of the coated aggregate will pass a 100 mesh screen. Also disclosed is a method for making such a composition.

Composition for use in dry products

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.

High energy density lead magnesium niobate-based dielectric ceramic and

Provided is a carbonaceous binder composition which comprises a polymerized and dehydrated carbohydrate, a monomer or polymer of resorcinol, and water. It is important that the carbohydrate is a polymer when combined with the remaining components of the composition. Polymerization of the carbohydrate prior to being combined with the other components of the composition has been found to result in an increased carbon yield upon pyrolysis of the binder. The binder composition also has an effective shelf life of three months or longer and gives off no objectionable smell either before or after being pyrolyzed. More importantly, the binder is also free of any skin or respiratory irritants, and is in effect non-carcinogenic.

Carbonaceous binder

A sol-gel method is disclosed for the production of polycrystalline strontium barium niobate (SBN) materials. Ceramic SBN materials produced in accordance with this method possess favorable ferroelectric properties, and are useful for electro-optic applications.

Sol-gel preparation of polycrystalline strontium barium niobate (SBN)

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.

Growing community of inventors

Washington, DC, United States of America

Keith Bridger