Engineering topics

Lavelle, Joseph R.

Publications and source records attributed to Lavelle, Joseph R..

3 records

NASA NTRS1990

Measuring Concentration Of Ozone Automatically

Airborne photometer measures absorption of ultraviolet. Automatically measures ozone concentrations in atmosphere to accuracy within 10 parts per billion. Air collected outside airplane enters photometer by way of transfer valve. Pressure and temperature of air measured simultaneously with transmissivity of air to ultraviolet light from lamp. Instrument has mass of 20.5 kg and fits in aluminum box measuring 78 by 58 by 25 cm. Compact, lightweight, low-power instrument developed for use on high-altitude research airplane.

Lavelle, Joseph R.↗

NASA NTRS1988

An automated ozone photometer

A photometer capable of automatically measuring ozone concentration data to very high resolution during scientific research flights in the Earth's atmosphere was developed at NASA Ames Research Center. This instrument was recently deployed to study the ozone hole over Antarctica. Ozone is detected by absorbing 253.7-nm radiation from an ultraviolet lamp which shines through the sample of air and impinges on a vacuum phototube. A lower output from the phototube indicates more ozone present in the air sample. The photometer employs a CMOS Z80 microprocessor with an STD bus system for experiment control, data collection, and storage. Data are collected and stored in nonvolatile memory for experiments lasting up to 8 hr. Data are downloaded to a portable ground-support computer and processed after the aircraft lands. An independent single-board computer in the STD bus also calculates ozone concentration in real time with less resolution than the CMOS Z80 system, and sends this value to a cockpit meter to aid the pilot in navigation.

Lavelle, Joseph R.↗

NASA NTRS1988

An automated ozone photometer

A photometer capable of automatically measuring ozone concentration data to very high resolution during scientific research flights in the earth's atmosphere was developed at the NASA Ames Research Center. This instrument was recently deployed to study the ozone hole over Antarctica. Ozone is detected by absorbing 253.7-nm radiation from an ultraviolet lamp which shines through the sample of air and impinges on a vacuum phototube. A lower output from the phototube indicates more ozone present in the air sample. The photometer employs a CMOS 280 control, data collection, and storage.

Lavelle, Joseph R.↗