title: Novel sensor technology for monitoring and control of critical plant nutrient parameters.
abstract: A novel dielectric sensor technology has been developed for monitoring and control of plant nutrient delivery systems as part of NASA's Controlled Ecological Life Support System (CELSS) program. A unique measurement phenomenon was discovered in which the electrostatic field is shunted to a third terminal of the sensor, resulting in a much greater sensitivity to changes in the complex dielectric properties of the nutrient solution. Based on this phenomenon, a small, flexible, thin-film shunting dielectric sensor (SDS) was designed to provide low-frequency, non-invasive measurement of both the thickness and nutrient concentration of the layer of solution on a plant growth surface. Test results indicate a sensitivity of +/- 0.05mm in layer thickness while characterization of the ability to measure nutrient concentration continues. The development plan for this sensor is presented and other applications are discussed.
authors.affiliation: Axiomatics Corporation, Woburn, MA 01801, USA.
authors.forename: F A
authors.initials: FA
authors.lastname: Waldman
authors.forename: C R
authors.initials: CR
authors.lastname: Davis
mesh_terms: D000465:Algorithms; D018533:Biomass; D003470:Culture Media / Q000032:analysis; D018504:Ecological Systems, Closed; D004566:Electrodes; D004780:Environment, Controlled; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D018527:Hydroponics / Q000295:instrumentation* / Q000379:methods; D008021:Life Support Systems / Q000295:instrumentation*; D018517:Plant Roots / Q000254:growth & development*; D012815:Signal Processing, Computer-Assisted; D012984:Software; D018531:Spacecraft / Q000295:instrumentation; D055672:Static Electricity; D018581:Technology Transfer
chemical_list: D003470:Culture Media