May 2021 * Vol. 45 No. 5 Contents Features 16 10 Products of Tomorrow 16 Cleaner, Faster Flight is on the Horizon 49 Application Briefs 52 Facility Focus 56 NASA Spinoff: In-Home Tankless Water Heaters 22 Tech Briefs 22 Test & Measurement 22 Extreme Low-Frequency Hydrophone 22 Chip Delivers COVID-19 Test Results on a Smartphone 24 Cord Tension Measurement Device 25 Disease-Sniffing Device Rivals a Dog's Nose 26 Device Measures Toxic Lead in Minutes 27 Sensors 27 Biometric Security System Based on the Human Heartbeat 27 Paper-Based Sensor Detects COVID-19 in Minutes 28 Ultra-Sensitive Flow Microsensors 29 RFID-Based Rotary Position Sensor 30 Carbon-Based Air Quality Sensor 30 Passive Polarized Fiber Optic Sensing 31 Accelerometer and Gyroscope Designs Based on Carbon Nanotube Tape 32 Aeronautics 32 52 Departments 8 UpFront 12 5 Ws Hinge Design Helps Quadrotors Climb 14 Q&A 32 System Helps Drones Detect and Avoid Power Lines 55 Advertisers Index 34 Navigation Algorithm Enables Drones to Learn Acrobatic Maneuvers 34 Predicting In-Flight Air Density for More Accurate Landing 35 Turbulence Model for Design of Aircraft Capable of Handling Extreme Scenarios 36 Propulsion 36 High-Power Microwaves for Launching Space-Bound Rockets 36 Hybrid-Electric Plane Concept Could Reduce Air Pollution 37 Hybrid Propellant Formulation Uses Graphene Foams New for Design Engineers 50 New on the Market (Propulsion continued on page 6) 4 www.techbriefs.com Cov ToC Tech Briefs, May 2021http://www.techbriefs.com http://www.abpi.net/ntbpdfclicks/l.php?202105TBNAV