Computer Science – Performance
Scientific paper
Jan 1997
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997adspr..20.1861c&link_type=abstract
Advances in Space Research, Volume 20, Issue 10, p. 1861-1867.
Computer Science
Performance
1
Scientific paper
The variable pressure growth chamber (VPGC) was used in a 34-day functional test to grow a wheat crop using reduced pressure (70 kPa) episodes totalling 131 hours. Primary goals of the test were to verify facility and subsystem performance at 70 kPa and to determine responses of a wheat stand to reduced pressure and modified partial pressures of carbon dioxide and oxygen. Operation and maintenance of the chamber at 70 kPa involved continuous evacuation of the chamber atmosphere, leading to CO_2 influx and efflux. A model for calculating CO_2-exchange rates (net photosynthesis and dark respiration) was developed and tested and involved measurements of chamber leakage to determine appropriate corrections. Measurement of chamber leakage was based on the rate of pressure change over a small pressure increment (70.3 to 72.3 kPa) with the pump disabled. Leakage values were used to correct decreases and increases in chamber CO_2 concentration resulting from net photosynthesis (Ps) and dark respiration (DR), respectively. Composite leakage corrections (influx and efflux) at day 7 of the test were 9 % and 19 % of the changes measured for Ps and DR, respectively. On day 33, composite corrections were only 3 % for Ps and 4 % for DR. During the test, the chamber became progressively tighter; the leak rate at 70.3 kPa decreasing from 2.36 chamber volumes/day pretest, to 1.71 volumes/day at the beginning of the test, and 1.16 volumes/day at the end of the test. Verification of the short-term leakage tests (rate of pressure rise) were made by testing CO_2 leakage with the vacuum pump enabled and disabled. Results demonstrate the suitability of the VPGC for conducting gas exchange measurements of a crop stand at reduced pressure.
Barta D. J.
Corey Kenneth A.
Edeen M. A.
Henninger Donald L.
No associations
LandOfFree
Atmospheric leakage and method for measurement of gas exchange rates of a crop stand at reduced pressure does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Atmospheric leakage and method for measurement of gas exchange rates of a crop stand at reduced pressure, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Atmospheric leakage and method for measurement of gas exchange rates of a crop stand at reduced pressure will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1783023