Johns Hopkins University

Other

Arete Associates

Aret&eacute; Associates

Allan B Fraser

Guy J Farruggia

Harvey Wayne Ko

Micah A Carlson

Terry E Phillips

Charles W Anderson

Richard C Benson

David R Kohler

C Brent Bargeron

John D Groopman

Paul T Strickland

John K Hudak

Techniques and apparatus inhibit, limit, or remove biofouling and certain inorganic accumulations, to increase the longevity of accurate in-situ oceanographic and other underwater measurements and transducing processes. The invention deters formation of an initial bacterial layer and other precipitation, without harming the environment. The invention integrates an ultrasonic source into a sensor or other device, or its supporting structures. The ultrasonic source vibrates one or more critical surfaces of the device at a frequency and amplitude that dislodge early accumulations, thus preventing the rest of the fouling sequence. The ultrasonic driver is activated for short periods and low duty cycles, and in some cases preferably while the device is not operating.

Self-cleaning submerged instrumentation

A hand held, self-contained, automatic, low power and rapid sensor platform for detecting and quantifying a plurality of analytes. A sample solution potentially containing an unknown amount of an analyte is passed through an affinity column which contains antibodies to which the analyte binds thereby extracting the analyte. The affinity column is then rinsed to remove any other chemicals that may fluoresce. The rinsed affinity column is then eluted with a known volume of elution fluid causing the analyte to release from the antibody and dissolve in the fluid (eluant). The eluant is then placed in the quartz cuvette of a fluorometer. The analyte suspended in the eluant fluoresces at a waveband which is different than that of the light source that excites it. The amount of fluorescence is measured and the level of analyte determined. The rinsing and elution fluids, and/or the affinity column can be placed in a module for easy insertion and removal from the sensor when depleted or when the sensor is to be used against a different analyte.

Miniature immuno-optical rapid analyte sensor platform

Liquid conductivity and temperature are measured in respective sensitivity fields that are collocated&mdash;i. e., in volumes that nearly match by mathematical, geometrical, or functional criteria. Collocation is as distinct from mere adjacency or proximity; and is with respect to measurement volumes, not measuring hardware. Preferably pressure too is measured with sensitivity very generally collocated to the conductivity and temperature sensitivity. Preferably, respective temporal/spatial bandwidths of the two (or three) sensors are matched. Preferably the pressure sensor is a MEMS transducer, the conductivity sensor is a four-terminal device, the thermometer is a thermistor encapsulated in a silkscreened glass wall, and circuits (1) compensate for time lag between conductivity and temperature measurement, (2) remove artifacts due to detritus in or near either sensor, and (3) derive secondary parameters of the liquid.

Sensor and sensor system for liquid conductivity, temperature and depth

The present invention is a heated element sensor for detecting the flow rate of a fluid or other physical characteristics of a fluid. The invention teaches driving the thermo-resistive element along a profile having at least two states and measuring the power and temperature of the sensor at each state. In this way a dissipation coefficient can be determined and fluid flow and other physical characteristics determined without the need for ambient temperature to be determined.

Heated element velocimeter

A frequency encoding closed loop circuit with transducer, comprising a closed inner digital loop nested in a closed outer loop which carries both digital and analog signals, associates a corresponding frequency output to variations in the magnitude of physical quantity input to a transducer which is contained within the outer loop. The encoder achieves the advantage of synchronous detection in converting changes in a transduced quantity into a frequency count. The encoder produces frequency shifts at its output that are proportional to the transducer input and are significantly immune to noise and power input fluctuations.

Frequency encoding closed loop circuit with transducer

Growing community of inventors

Woodbine, MD, United States of America

Allan B Fraser