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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1995

Spectrometric Estimation of Total Nitrogen Concentration in Douglas-Fir Foliage

Spectral measurements of fresh and dehydrated Douglas-fir foliage, from trees cultivated under three fertilization treatments, were acquired with a laboratory spectrophotometer. The slope (first-derivative) of the fresh- and dry-leaf absorbance spectra at locations near known protein absorption features was strongly correlated with total nitrogen (TN) concentration of the foliage samples. Particularly strong correlation was observed between the first-derivative spectra in the 2150-2170 nm region and TN, reaching a local maximum in the fresh-leaf spectra of -0.84 at 2 160 nm. Stepwise regression was used to generate calibration equations relating first derivative spectra from fresh, dry/intact, and dry/ground samples to TN concentration. Standard errors of calibration were 1.52 mg g-1 (fresh), 1.33 (dry/intact), and 1.20 (dry/ground), with goodness-of-fit 0.94 and greater. Cross-validation was performed with the fresh-leaf dataset to examine the predictive capability of the regression method; standard errors of prediction ranged from 1.47 - 2.37 mg g(exp -1) across seven different validation sets, prediction goodness of fit ranged from .85-.94, and wavelength selection was fairly insensitive to the membership of the calibration set. All regressions in this study tended to select wavelengths in the 2100-2350 nm region, with the primary selection in the 2142-2172 nm region. The study provides positive evidence concerning the feasibility of assessing TN status of fresh-leaf samples by spectrometric means. We assert that the ability to extract biochemical information from fresh-leaf spectra is a necessary but insufficient condition regarding the use of remote sensing for canopy-level biochemical estimation.

Johnson, Lee F.↗
NASA NTRS1995

Hierarchical analysis of spatial pattern and processes of Douglas-fir forests

There has been an increased interest in the quantification of pattern in ecological systems over the past years. This interest is motivated by the desire to construct valid models which extend across many scales. Spatial methods must quantify pattern, discriminate types of pattern, and relate hierarchical phenomena across scales. Wavelet analysis is introduced as a method to identify spatial structure in ecological transect data. The main advantage of the wavelet transform over other methods is its ability to preserve and display hierarchical information while allowing for pattern decomposition. Two applications of wavelet analysis are illustrated, as a means to: (1) quantify known spatial patterns in Douglas-fir forests at several scales, and (2) construct spatially-explicit hypotheses regarding pattern generating mechanisms. Application of the wavelet variance, derived from the wavelet transform, is developed for forest ecosystem analysis to obtain additional insight into spatially-explicit data. Specifically, the resolution capabilities of the wavelet variance are compared to the semi-variogram and Fourier power spectra for the description of spatial data using a set of one-dimensional stationary and non-stationary processes. The wavelet cross-covariance function is derived from the wavelet transform and introduced as a alternative method for the analysis of multivariate spatial data of understory vegetation and canopy in Douglas-fir forests of the western Cascades of Oregon.

Bradshaw, G. A.↗
NASA NTRS1992

Soil nitrogen cycling and nitrous oxide flux in a Rocky Mountain Douglas-fir forest - Effects of fertilization, irrigation and carbon addition

Nitrous oxide fluxes and soil nitrogen transformations were measured in experimentally-treated high elevation Douglas-fir forests in northwestern New Mexico. On an annual basis, forests that were fertilized with 200 kg N/ha emitted an average of 0.66 kg/ha of N2O-N, with highest fluxes occurring in July and August when soils were both warm and wet. Control, irrigated, and woodchip treated plots were not different from each other, and annual average fluxes ranged from 0.03 to 0.23 kg/ha. Fertilized soil mineralized 277 kg/ha per year in contrast to 18 kg/ha per year in control plots. Relative recovery of (N-15)H4-N applied to soil in laboratory incubations was principally in the form of NO3-N in the fertilized soils, while recovery was mostly in microbial biomass-N in the other treatments. Fertilization apparently added nitrogen that exceeded the heterotrophic microbial demand, resulting in higher rates of nitrate production and higher nitrous oxide fluxes. Global inputs of nitrogen into forests are not currently contributing significantly to the increasing concentrations of nitrous oxide in the atmosphere.

Matson, Pamela A.↗
NASA NTRS1992

Soil nitrogen cycling and nitrous oxide flux in a Rocky Mountain Douglas-fir forest - Effects of fertilization, irrigation and carbon addition

Nitrous oxide fluxes and soil nitrogen transformations were measured in experimentally-treated high elevation Douglas-fir forests in northwestern New Mexico, USA. On an annual basis, forests that were fertilized with 200 kg N/ha emitted an average of 0.66 kg/ha of N2O-N, with highest fluxes occurring in July and August when soils were both warm and wet. Control, irrigated, and woodchip treated plots did not differ, and annual average fluxes ranged from 0.03 to 0.23 kg/ha. Annual net nitrogen mineralization and nitrate production were estimated in soil and forest floor using in situ incubations; fertilized soil mineralized 277 kg/ha/y in contrast to 18 kg/ha/y in control plots. Relative recovery of 15NH4-N applied to soil in laboratory incubations was principally in the form of NO3-N in the fertilized soils, while recovery was mostly in microbial biomass-N in the other treatments. Fertilization apparently added nitrogen that exceeded the heterotrophic microbial demand, resulting in higher rates of nitrate production and higher nitrous oxide fluxes. Despite the elevated nitrous oxide emission resulting from fertilization, we estimate that global inputs of nitrogen into forests are not currently contributing significantly to the increasing concentrations of nitrous oxide in the atmosphere.

Matson, Pamela A.↗
NASA NTRS2001

Induced compression wood formation in Douglas fir (Pseudotsuga menziesii) in microgravity

In the microgravity environment of the Space Shuttle Columbia (Life and Microgravity Mission STS-78), were grown 1-year-old Douglas fir and loblolly pine plants in a NASA plant growth facility. Several plants were harnessed (at 45 degrees ) to establish if compression wood biosynthesis, involving altered cellulose and lignin deposition and cell wall structure would occur under those conditions of induced mechanical stress. Selected plants were harnessed at day 2 in orbit, with stem sections of specific plants harvested and fixed for subsequent microscopic analyses on days 8, 10 and 15. At the end of the total space mission period (17 days), the remaining healthy harnessed plants and their vertical (upright) controls were harvested and fixed on earth. All harnessed (at 45 degrees ) plant specimens, whether grown at 1 g or in microgravity, formed compression wood. Moreover, not only the cambial cells but also the developing tracheid cells underwent significant morphological changes. This indicated that the developing tracheids from the primary cell wall expansion stage to the fully lignified maturation stage are involved in the perception and transduction of the stimuli stipulating the need for alteration of cell wall architecture. It is thus apparent that, even in a microgravity environment, woody plants can make appropriate corrections to compensate for stress gradients introduced by mechanical bending, thereby enabling compression wood to be formed. The evolutionary implications of these findings are discussed in terms of "variability" in cell wall biosynthesis.

manned↗
NASA NTRS1992

Estimating structural attributes of Douglas-fir/western hemlock forest stands from Landsat and SPOT imagery

Relationships between spectral and texture variables derived from SPOT HRV 10 m panchromatic and Landsat TM 30 m multispectral data and 16 forest stand structural attributes is evaluated to determine the utility of satellite data for analysis of hemlock forests west of the Cascade Mountains crest in Oregon and Washington, USA. Texture of the HRV data was found to be strongly related to many of the stand attributes evaluated, whereas TM texture was weakly related to all attributes. Data analysis based on regression models indicates that both TM and HRV imagery should yield equally accurate estimates of forest age class and stand structure. It is concluded that the satellite data are a valuable source for estimation of the standard deviation of tree sizes, mean size and density of trees in the upper canopy layers, a structural complexity index, and stand age.

Cohen, Warren B.↗
NASA NTRS1995

Analysis of conifer forest regeneration using Landsat Thematic Mapper data

Landsat Thematic Mapper (TM) data were used to evaluate young conifer stands in the western Cascade Mountains of Oregon. Regression and correlation analyses were used to describe the relationships between TM band values and age of young Douglas-fir stands (2 to 35 years old). Spectral data from well regenerated Douglas-fir stands were compared to those of poorly regenerated conifer stands. TM bands 1, 2, 3, 5, 6, and 7 were inversely correlated with the age (r greater than or equal to -0.80) of well regenerated Douglas-fir stands. Overall, the 'structural index' (TM 4/5 ratio) had the highest correlation to age of Douglas-fir stands (r = 0.96). Poorly regenerated stands were spectrally distinct from well regenerated Douglas-fir stands after the stands reached an age of approximately 15 years.

Fiorella, Maria↗
NASA NTRS1972

Potentiality for obtaining poria disease signatures in the Oregon Cascades from orbital altitudes

A prime photographic signature indicator of an important forest disease was identified in valuable Douglas-fir stands of the Pacific Northwest. The disease signature was verified by a multidisciplinary team of scientists to be the direct result of the Poria weirii root-rot syndrome in the Douglas-fir and hemlock stands of the high Cascades in Oregon. It is readily discernible on small-scale suborbital photography and has good potential for detection from earth-orbiting satellites or remote sensing platforms.

Wear, J. F.↗
NASA NTRS1978

Concentration-response data on toxicity of pyrolysis gases from some natural and synthetic polymers

Concentration-response data are presented on the toxic effects of the pyrolysis gases from some natural and synthetic polymers, using the toxicity screening test method developed at the University of San Francisco. The pyrolysis gases from wool, red oak, Douglas fir, polycaprolactam, polyether sulfone, polyaryl sulfone, and polyphenylene sulfide appeared to exhibit the concentration-response relationships commonly encountered in toxicology. Carbon monoxide seemed to be an important toxicant in the pyrolysis gases from red oak, Douglas fir, and polycaprolactam, but did not appear to have been the principal toxicant in the pyrolysis gases from polyether sulfone and polyphenylene sulfide.

Hilado, C. J.↗
NASA NTRSDate not supplied

Comparing the Regional Variability of Emission Factors of Greenhouse Gases Over Different Landscape During FIREX-AQ Campaign

Biomass burning (wildfires, prescribed and agricultural burning) is one of the major sources of trace gases and particulate emissions and annual variability in growth rates. Biomass burning can impact local, regional, and global air quality, as well as climate. Measurements of emissions from biomass burning are crucial to a better understanding of how it influences and interacts with biogeochemical cycles. High resolution in-situ measurements were recorded onboard the NASA DC-8 aircraft during the FIREX-AQ (Fire Influence on Regional to Global Environments and Air Quality) airborne field campaign July-September, 2019, which was conducted over the continental U.S. Fire emission factors (EF) are essential input for emissions models used to develop biomass burning emission inventories. Here we present the Emission Ratio (ER), MCE (Modified Combustion Efficiency), and EF (Emission Factor) of CO2, CO, and CH4, which constitute the majority of carbon emitted from the wildland, prescribed, and agricultural fires. EFCO2, EFCO, and EFCH4 from the Wildland fires at Williams Flats, WA (primarily Douglas Fir, Ponderosa pine, wheatgrass: 50-75%), ranged from 1527 – 1820 g/kg (Avg. 1641±42), 6.5 – 174.1 g/kg (110.5±24.1), and 0.7 – 11.3 g/kg (6.2±1.9), respectively. EFs from the Arizona CASTLE fire, with somewhat different fuel sources (primarily Ponderosa pine, Douglas fir: 40-70%) ranged from 1266 – 1667 g/kg (1596±59), 99.5 – 344.5 g/kg (136.7±36.8), and 0.4 – 9.2 g/kg (7.2±1.7), respectively. Another primary driver of EFs is likely fire weather. Detailed variability of greenhouse gas EFs will be examined and presented in accordance with different fuels and fire conditions at burned areas, specifically within unique wildland and croplands, using the FCCS (Fuel Characteristic Classification System) 30m land cover identification and the Cropland Data Layer (CDL).

Biomass burning↗
NASA NTRSDate not supplied

Comparing the regional variability of emission factors of greenhouse gases over different landscape during FIREX-AQ campaign

Biomass burning (wildfires, prescribed and agricultural burning) is one of the major sources of trace gases and particulate emissions and annual variability in growth rates. Biomass burning can impact local, regional, and global air quality, as well as climate. Measurements of emissions from biomass burning are crucial to a better understanding of how it influences and interacts with biogeochemical cycles. High resolution in-situ measurements were recorded onboard the NASA DC-8 aircraft during the FIREX-AQ (Fire Influence on Regional to Global Environments and Air Quality) airborne field campaign July-September, 2019, which was conducted over the continental U.S. Fire emission factors (EF) are essential input for emissions models used to develop biomass burning emission inventories. Here we present the Emission Ratio (ER), MCE (Modified Combustion Efficiency), and EF (Emission Factor) of CO2, CO, and CH4, which constitute the majority of carbon emitted from the wildland, prescribed, and agricultural fires. EFCO2, EFCO, and EFCH4 from the Wildland fires at Williams Flats, WA (primarily Douglas Fir, Ponderosa pine, wheatgrass: 50-75%), ranged from 1527 – 1820 g/kg (Avg. 1641±42), 6.5 – 174.1 g/kg (110.5±24.1), and 0.7 – 11.3 g/kg (6.2±1.9), respectively. EFs from the Arizona CASTLE fire, with somewhat different fuel sources (primarily Ponderosa pine, Douglas fir: 40-70%) ranged from 1266 – 1667 g/kg (1596±59), 99.5 – 344.5 g/kg (136.7±36.8), and 0.4 – 9.2 g/kg (7.2±1.7), respectively. Another primary driver of EFs is likely fire weather. Detailed variability of greenhouse gas EFs will be examined and presented in accordance with different fuels and fire conditions at burned areas, specifically within unique wildland and croplands, using the FCCS (Fuel Characteristic Classification System) 30m land cover identification and the Cropland Data Layer (CDL).

Biomass burning↗
NASA NTRS1990

Structural properties of laminated Douglas fir/epoxy composite material

This publication contains a compilation of static and fatigue strength data for laminated-wood material made from Douglas fir and epoxy. Results of tests conducted by several organizations are correlated to provide insight into the effects of variables such as moisture, size, lamina-to-lamina joint design, wood veneer grade, and the ratio of cyclic stress to steady stress during fatigue testing. These test data were originally obtained during development of wood rotor blades for large-scale wind turbines of the horizontal-axis (propeller) configuration. Most of the strength property data in this compilation are not found in the published literature. Test sections ranged from round cylinders 2.25 in. in diameter to rectangular slabs 6 by 24 in. in cross section and approximately 30 ft. long. All specimens were made from Douglas fir veneers 0.10 in. thick, bonded together with the WEST epoxy system developed for fabrication and repair of wood boats. Loading was usually parallel to the grain. Size effects (reduction in strength with increase in test volume) are observed in some of the test data, and a simple mathematical model is presented that includes the probability of failure. General characteristics of the wood/epoxy laminate are discussed, including features that make it useful for a wide variety of applications.

Spera, David A.↗
NASA NTRS1989

Determining experimentally induced variation in coniferous canopy chemistry with Airborne Imaging Spectrometer data

Experimental treatments in a Douglas-fir forest in NE New Mexico were carried out to determine whether differences in forest canopy chemistry could be detected using data from the Airborne Imaging Spectrometer (AIS-2). Experimental treatments consisted of nitrogen fertilizer additions, sawdust additions, and control plots. After AIS-2 data were collected, the digital number of a given pixel was extracted from each channel, yielding 128 values that were used to form a spectrum. Four spectra were extracted from each treatment plot. Multiple stepwise linear regressions between first and second difference transformations of AIS-2 spectra and the canopy characteristics of biomass, nitrogen concentration, and nitrogen content were performed. The results showed a coefficient of multiple determination of 0.71 between first-difference AIS-2 spectra and measured nitrogen concentration in foliage, indicating that it may be possible to predict nitrogen concentration in Douglas fir using AIS-2 spectra.

Swanberg, N. A.↗
NASA NTRS1970

The development of spectro-signature indicators of root disease impacts on forest stands

A field research program was begun in 1969 and intensified in 1970 on the physiology and biophysical responses of second-growth Douglas fir infected with root rot fungus. A double tramway system was suspended between three 100-foot instrument towers to carry sensors for measuring the energy response from above both healthy and infected trees. Processing and analysis was completed of airborne multispectral scanner imagery collected over the Wind River research area in 1969. Likelihood ratio processing of three-channel infrared data and Euclidean distance analysis of ten-channel spectrometer data did not identify incipient root rot infection outside the training sets. In all cases infected fir was misclassified as healthy fir. It was concluded from careful examination of physiological data that Poria root rot infection has little effect on water metabolism and energy exchange. What was identified was a low-grade stress that affects respiration and metabolism over long periods of time. This led to minor changes in the external physical symptoms of Poria-infected trees which was revealed only in the shortwave reflectance data.

Weber, F. P.↗
NASA NTRS1974

Inventory of forest and rangeland and detection of forest stress

The author has identified the following significant results. Controlled visual interpretation of one ERTS-1 scene taken at the peak of the growing season has indicated that classification to the ECOCLASS Series level is not entirely satisfactory. For five forest classes, aspen, Douglas-fir, lodgepole pine, ponderosa pine, and Spruce/fir, correct identification ranged from 60 to 70 percent. With the exception of shortgrass and wet shrubby meadow classes in the nonforest categories (81 and 100 percent correct, respectively), correct identification of the nonforest classes is so far unacceptable. The low accuracies are believed due to: (1) edge effects due to ecotones between plant community classes with apparent similar image characteristics; (2) confounding effects of amount of plant crown cover and ground surface material in the scene; and (3) variable land slope degree and aspect as it affects the image signature.

Heller, R. C.↗
NASA NTRS1976

The effect of changes in the USF/NASA toxicity screening test method on data from some cellular polymers

Rankings of relative toxicity can be markedly affected by changes in test variables. Revision of the USF/NASA toxicity screening test procedure to eliminate the connecting tube and supporting floor and incorporate a 1.0 g sample weight, 200 C starting temperature, and 800 C upper limit temperature for pyrolysis, reversed the rankings of flexible polyurethane and polychloroprene foams, not only in relation to each other, but also in relation to cotton and red oak. Much of the change is attributed to reduction of the distance between the sample and the test animals, and reduction of the sample weight charged. Elimination of the connecting tube increased the relative toxicity of the polyurethane foams. The materials tested were flexible polyurethane foam, without and with fire retardant; rigid polyurethane foam with fire retardant; flexible polychloroprene foam; cotton, Douglas fir, red oak, hemlock, hardboard, particle board, polystyrene, and polymethyl methacrylate.

Hilado, C. J.↗