ognizant Communication Corporation


VOLUME 6, NUMBER 4, 1999

Life Support & Biosphere Science, Vol. 6, pp. 259-263, 1999
1069-9422/99 $10.00 + .00
Copyright © 1999 Cognizant Comm. Corp.
Printed in the USA. All rights reserved.

Modeling Wheat Harvest Index as a Function of Date of Anthesis

Marvin J. Pitts1 and Garry W. Stutte2

1Biological Systems Engineering, Washington State University, Pullman, WA 99164-6120
2Dynamac Corp., Mail Code DNY-3, Kennedy Space Center, FL 32899

A plant growth model developed by Volk and colleagues was modified to partition plant mass production after anthesis into grain and inedible biomass. Using data on wheat (Triticum aestivum) grown in the NASA CELSS Biomass Production Chamber to supply constants for the model, we showed that delaying the date of anthesis 7 days resulted in a 20% decrease in the harvest index. Multiple model components were then assembled to demonstrate the effect of an environmental system failure.

Key Words: Plant simulation; Anthesis; Wheat; Harvest index

Address correspondence to Marvin J. Pitts. Tel: (509) 335-3243; Fax: (509) 335-2722; E-mail: pitts@wsu.edu

Life Support & Biosphere Science, Vol. 6, pp. 265-271, 1999
1069-9422/99 $10.00 + .00
Copyright © 1999 Cognizant Comm. Corp.
Printed in the USA. All rights reserved.

Multivariable Empirical Modeling of ALS Systems Using Polynomials

David A. Vaccari and Julie Levri

Department of Civil, Environmental and Ocean Engineering, Stevens Institute of Technology, Hoboken, NJ 07030

Multivariable polynomial regression (MPR) was used to model plant motion time-series and nutrient recovery data for Advanced Life Support (ALS). MPR has capabilities similar to neural network models in terms of ability to fit multiple-input single-output nonlinear data. It has advantages over neural networks including: reduced overfitting; produces models that are more tractable for optimization, sensitivity analysis, and prediction of confidence intervals. MPR was used to produce nonlinear polynomial time-series models predicting plant projected canopy area versus time and temperature. Temperature was found to not have a statistically significant effect. Models were developed to relate rate and extent of nutrient recovery to treatment parameters, including temperature and use of heat pretreatment or nutrient supplementation. These applications demonstrate MPR's capability to fill "gaps" in an integrated model of ALS. Fundamental models should be used whenever available. However, some components may require empirical modeling. Furthermore, even fundamental models often have empirical constituents. MPR models are proposed to satisfy these needs.

Key Words: Empirical; Polynomial; Modeling; Nutrient recovery; Plant motion

Address correspondence to David A. Vaccari, Ph.D. Tel: (201) 216-5570; Fax: (201) 216-5352; E-mail: dvaccari@stevens-tech.edu

Life Support & Biosphere Science, Vol. 6, pp. 273-278, 1999
1069-9422/99 $10.00 + .00
Copyright © 1999 Cognizant Comm. Corp.
Printed in the USA. All rights reserved.

Phasic Temperature and Photoperiod Control for Soybean Using a Modified CROPGRO Model

James Cavazzoni,1 Tyler Volk,2 Bruce Bugbee,3 and Tracy Dougher3

1Department of Bioresource Engineering, Rutgers, The State University of New Jersey, 20 Ag Extension Way, New Brunswick, NJ 08901-8500
2Department of Biology, 1009 Main Bldg., New York University, New York, NY 10003
3Department of Plant, Soils, and Biometeorology, Utah State University, Logan, UT 84322-4820

A modified CROPGRO model is applied to phasic temperature and photoperiod control in order to optimize soybean production for NASA's program in Advanced Life Support. Baseline model simulations were established using data from soybean temperature experiments conducted at elevated CO2 levels (1100 mmol mol-1) at Utah State University (USU). The model simulations show little advantage in using phasic temperature control alone to increase average seed yield rate over the USU experimental values. However, simulations that combine phasic control of temperature (two phases) and photoperiod (two phases) do indicate the potential to improve seed yield (in g m-2 day-1) by approximately 15% over those currently obtained experimentally at USU for soybean cultivar Hoyt. This temperature and photoperiod phasing is experimentally practical. The simulations suggest extending photoperiods over those typically used experimentally during later phases of the crop life cycle, which would lengthen grain fill duration and thereby increase mass per seed. The model simulations indicate that the timing and duration of extended photoperiods would be very important due to possible reductions in seed number m-2. Besides affecting seed yield directly, the model simulations suggest that such reductions may also cause feedback inhibition of photosynthesis due to low seed sink strength at elevated CO2 levels.

Key Words: Phasic control; Advanced life support; Soybean modeling; CROPGRO

Address correspondence to James Cavazzoni. Tel: (732) 932-9753; Fax: (732) 932-7931;    E-mail:cavazzon@bioresource.rutgers.edu.

Life Support & Biosphere Science, Vol. 6, pp. 279-285, 1999
1069-9422/99 $10.00 + .00
Copyright © 1999 Cognizant Comm. Corp.
Printed in the USA. All rights reserved.

Coupling Machine Vision and Crop Models for Closed-Loop Plant Production in Advanced Life Support Systems

James Cavazzoni1 and Peter P. Ling2

1Department of Bioresource Engineering, Rutgers, The State University of New Jersey, 20 Ag Extension Way, New Brunswick, NJ 08901-8500
2Food, Agricultural, and Biological Engineering Department, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691

We present a conceptual framework for coupling nondestructive sensing to crop models for closed-loop plant production for NASA's program in advanced life support. Coupling is achieved by comparing nondestructive observations with model predictions of plant growth and development. The information thus provided may be useful in diagnosing problems with the plant growth system, or as a feedback to the model for evaluation of plant scheduling and potential yield. We illustrate this concept using canopy height and machine vision measured top projected canopy area (TPCA), and the CROPGRO crop growth model. Model simulations of soybean TPCA and canopy height were evaluated against data for hydroponic soybean grown under two separate light/dark cycle temperature regimes (23/19°C and 26/22°C). Our results suggest that TPCA and canopy height are potentially useful variables for closed-loop plant production in controlled environments during the first few weeks of growth, before canopy closure.

Key Words: Machine vision sensing; Controlled environment agriculture; Feedback control; Crop model

Address correspondence to James Cavazzoni. Tel: (732) 932-9753; Fax: (732) 932-7931; E-mail: cavazzon@bioresource.rutgers.edu

Life Support & Biosphere Science, Vol. 6, pp. 287-291, 1999
1069-9422/99 $10.00 + .00
Copyright © 1999 Cognizant Comm. Corp.
Printed in the USA. All rights reserved.

Theoretical and Practical Considerations of Staggered Crop Production in a BLSS

G. W. Stutte,1 C. L. Mackowiak,1 N. C. Yorio,1 and R. M. Wheeler2

1Dynamac Corporation, Kennedy Space Center, FL 32899
2Biomedical Office, Kennedy Space Center, FL 32899 USA

A functional Bioregenerative Life Support System (BLSS) will generate oxygen, remove excess carbon dioxide, purify water, and produce food on a continuous basis for long periods of operation. In order to minimize fluctuations in gas exchange, water purification, and yield that are inherent in batch systems, staggered planting and harvesting of the crop is desirable. A 418-day test of staggered production of potato cv. Norland (26-day harvest cycles) using nutrients recovered from inedible biomass was conducted at Kennedy Space Center. The results indicate that staggered production can be sustained without detrimental effects on BLSS life support functions. System yields of H2O, O2, and food were higher in staggered than batch plantings. Plants growing in staggered production or batch production on "aged" solution initiated tubers earlier, and were shorter than plants grown on "fresh" solution. This morphological response required an increase in planting density to maintain full canopy coverage. Plants grown in staggered production used available light more efficiently than the batch planting due to increased side lighting.

Key Words: Bioregenerative Life Support System (BLSS); Staggered crop production; Batch crop production; Potatoes

Address correspondence to G. W. Stutte. Tel: (321) 476-4319; Fax: (321) 853-2859; E-mail: gary.stutte-1@ksc.nasa.gov

Life Support & Biosphere Science, Vol. 6, pp. 293-302, 1999
1069-9422/99 $10.00 + .00
Copyright © 1999 Cognizant Comm. Corp.
Printed in the USA. All rights reserved.

Carbon Dioxide Transport By Proteic And Facilitated Transport Membranes

Michael C. Trachtenberg,1 C. K. Tu,2 Robert A. Landers,1 Richard C. Willson,3 Martin L. McGregor,1 Philip J. Laipis,6 John F. Kennedy,4 Marion Paterson,4 David N. Silverman,2 Daniel Thomas,5 Russell L. Smith,1 and Frederick B. Rudolph7

1The Sapient's Institute, PO Box 580586, Houston, TX 77258-0586
2Department of Pharmacology, University of Florida School of Medicine, Box 100267, HSC (ARB R5-179), Gainesville, FL 32610-0267
3Department of Chemical Engineering, University of Houston, 4800 Calhoun Ave., Houston, TX 77204-4792
4Birmingham Carbohydrate and Protein Technology Group, The University of Birmingham, Research Laboratory for the Chemistry of Bioactive Carbohydrates and Proteins, School of Chemistry, Birmingham B15 2TT, UK
5Universite de Technologie du Compiegne, URA No 1442 du CNRS, Laboratoire de Technologie Enzymatique, BP 529, 60205 Compiegne, France
6Department of Biochemistry and Molecular Biology, University of Florida School of Medicine, Box 100245, HSC (ARB 2-252A), Gainesville, FL 32610-02458
7Department of Biochemistry, Rice University, BCB MS 140, Geo. R. Brown Bldg., Rm. West 200 E, 6100 Main St., Houston, TX 77005-1892

Membrane separation of gases is governed by the permeability of each species across the membrane. The ratio of permeabilities yields the selectivity. Use of certain organic carriers in facilitated transport membranes and the CO2 converting enzyme carbonic anhydrase (CA) in proteic and facilitated transport membranes allows a dramatic increase in CO2selectivity over other gases. CA has a low Km (9 mM), which we predicted would allow it to scavenge CO2 to very low partial pressures. Our goal was to determine if CA could remove CO<->2<-> from an environment at levels of 0.1% or less. Prior measurements of CO2 transport across thin supported liquid membranes showed that addition of CA enhanced CO2 flux by 3- to 100-fold. Proteic films use bifunctional reagents (e.g., glutaraldehyde) to cross-link the enzyme forming a gel. Bovine serum albumin (BSA) is often added for structural stability. Using such a preparation we examined the ability of proteic films to improve CO2 selectivity and to scavenge CO2 from a mixed gas stream. Proof-of-concept results, measured by mass spectrometry, showed a fivefold improvement in CO2capture rate with maximal improvement at CO2 values of 1% partial pressure difference in the presence of 0 atm absolute difference. At 0.1% CO2the membrane exhibited a 76% improvement over controls. At 0.3% CO2 the improvement is about threefold. CA proteic membranes exhibit selectivity for CO2 over oxygen and nitrogen in excess of three orders of magnitude. A CA-based proteic or facilitated transport membrane should readily achieve CO2 partial pressures of 0.05% under CELSS conditions. In addition to proteic membranes we are exploring direct immobilization of engineered CA to ultra-high-permeability teflon membranes. Site-directed mutagenesis was used to add functional groups while retaining full enzymatic activity. These results provide a basis for development of far more efficient CO2 capture proteic and facilitated transport membranes with increased selectivity to values closer to 100-fold at 1% CO2. The result will be CO2 selectivity at 0.1% on the order of 400-fold. These results exceed those obtained with other technologies.

Key Words: Carbon dioxide; Enzymes; Facilitated transport; Space; Closed ecological life support

Address correspondence to Michael C. Trachtenberg at his current address: The Sapient's Institute, Rutgers University/Cook College, 301B Foran Hall 159 Dudley Rd., New Brunswick, NJ 08901. Tel: (732) 932-8978; Fax: (732) 932-9441; E-mail: miket@aesop.rutgers.edu