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DOE OSTI2025

Ground-Active Arthropod Diversity Under Energycane and Biomass Sorghum Production

Energycane and biomass sorghum are two of the most promising cellulosic energy crops in the southeastern US. Research on these two energy crops has focused mainly on biomass production, and there is a lack of knowledge on their ability to promote biodiversity and ecosystem services. This paper presents results from a comprehensive study on ground-active arthropod diversity in seven sites across five states in the southeastern US (Florida, Georgia, Louisiana, Mississippi, and Texas). Pitfall traps were deployed four times during each crop season for energycane, biomass sorghum, and a local reference conventional crop from 2020 to 2022. Arthropod abundance (individuals/(trap × day)) values were 4.9 ± 0.46, 3.7 ± 0.18, and 2.6 ± 0.16 (mean ± stderr) for conventional crops, biomass sorghum, and energycane, respectively, with a significant difference found only between conventional crops and energycane. Individuals were identified to arthropod orders, and Hill’s diversity indices were calculated based on the number of individuals in each arthropod order instead of the number of individuals in each arthropod species. Order-based arthropod richness values were 5.3, 5.2, and 4.8 for biomass sorghum, conventional crops, and energycane, with significant difference found only between biomass sorghum and energycane. There was no significant difference in the order-based Shannon diversity and Simpson diversity between the three crop types. The effective number of arthropod orders for the two energy crops decreased from 5.0 to 3.4 to 2.9 with increasing order of diversity from arthropod richness to Shannon diversity to Simpson diversity. The explained variability by environmental factors also decreased with increasing Hill’s order of diversity. The results from this study indicate no significant advantage in order-based arthropod diversity in growing biomass sorghum and energycane. This research fills a critical knowledge gap in understanding the impacts of cellulosic energy crop production on biodiversity and ecosystem services.

Yang, Yubin↗

DOE OSTI2025

Investigating Bacterial-Fungal Interactions using Fungal Highway Columns in Diverse Environments and Substrates

Bacterial-fungal interactions (BFIs) play an integral role in shaping microbial community composition, biogeochemical functions, spatial dynamics, and microbial dispersal. Mycelial networks created by filamentous fungi or other filamentous microorganisms (e.g., Oomycetes) act as 'fungal highways' that can be utilized by bacteria for transport throughout heterogeneous environments, greatly facilitating their mobility and granting them access to regions that may be challenging or impossible to reach on their own (e.g., due to air pockets within the soil). Several devices and experimental protocols have been created to study these fungal highways, including fungal highway columns. The fungal highway column designed by our group can be used for a variety of in situ or in vitro applications, as well as with diverse environmental and host-associated sample types. Herein, we describe the methods for performing experiments with these columns, including designing, printing, sterilizing, and preparing the devices. The options for analyzing data obtained from the use of these devices are also discussed here, and troubleshooting advice regarding potential pitfalls associated with experiments using fungal highway columns is offered. These devices can be used to gain a more comprehensive understanding of the diversity, mechanisms, and dynamics of fungal highway BFIs to provide valuable insights into the structural and functional dynamics within complex environments (e.g., soils) and across diverse habitats in which bacteria and fungi co-exist.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2024

Interpreting Mass and Radius Measurements of Neutron Stars with Dark Matter Halos

Abstract The high densities of neutron stars (NSs) could provide astrophysical locations for dark matter (DM) to accumulate. Depending on the DM model, these DM admixed NSs (DANSs) could have significantly different properties than pure baryonic NSs, accessible through X-ray observations of rotation-powered pulsars. We adopt the two-fluid formalism in general relativity to numerically simulate stable configurations of DANSs, assuming a fermionic equation of state (EOS) for the DM with repulsive self-interaction. The distribution of DM in the DANS as a halo affects the path of X-rays emitted from hot spots on the visible baryonic surface, causing notable changes in the pulse profile observed by telescopes such as NICER, compared to pure baryonic NSs. We explore how various DM models affect the DM mass distribution, leading to different types of dark halos. We quantify the deviation in observed X-ray flux from stars with each of these halos. We identify the pitfalls in interpreting mass and radius measurements of NSs inferred from electromagnetic radiation and constraining the baryonic matter EOS if these dark halos exist.

Shawqi, Shafayat (ORCID:0000000210956183)↗

NASA NTRS1971

Solid propellant selection and characterization

The techniques of propellant selection and characterization and the compromises that may be forced on the designer by the change of a propellant parameter are discussed. Rules for the selection of a general propellant type are presented. The characterization of various propellant properties is then approached parameter by parameter. Tailoring pitfalls and compromises are identified whenever possible, and appropriate cross references are used. Related design criteria monographs frequently are cited for a more detailed treatment of the topic under discussion. A list of source references is provided. These references, coupled with established texts in the field, should give the depth of knowledge necessary to the designer to aid in the selection of the most nearly optimum propellant for the design application.

Source record↗

NASA NTRS1972

Differential correction schemes in nonlinear regression

Classical iterative methods in nonlinear regression are reviewed and improved upon. This is accomplished by discussion of the geometrical and theoretical motivation for introducing modifications using generalized matrix inversion. Examples having inherent pitfalls are presented and compared in terms of results obtained using classical and modified techniques. The modification is shown to be useful alone or in conjunction with other modifications appearing in the literature.

Decell, H. P., Jr.↗

NASA NTRS1973

Differential Correction Schemes in Nonlinear Regression

Decell, H. P., Jr.↗

NASA NTRS1972

Theory and measurement of emittance properties for radiation thermometry applications.

Some basic concepts of radiation physics are briefly reviewed to provide an introduction to the radiative properties - including emittance, reflectance, absorptance, and transmittance - their definitions, interrelations, theory and methods of measurement. Analyzed data showing typical characteristics of temperature and wavelength dependence, surface effects and environmental influences on the radiation properties of selected classes of materials are presented. Emphasis is placed on those emittance properties of particular interest to conventional radiation thermometry applications, but sufficient generality on all properties is presented to be useful for new or unusual techniques where a more detailed understanding of the behavior of materials is desirable. Data sources are identified to assist the reader in locating property information. It is the intention of the paper to give the reader a background to become more fully aware of the pitfalls, limitations, but of course, advantages in the use of data from the literature. The paper is written in the form of an abbreviated review fully documenting the more important topics and concepts which can only be treated briefly.

Dewitt, D. P.↗

NASA NTRS1975

On Similarity Transformation and Geodetic Network Distortions Based on Doppler Satellite Observations

Models used in geodesy to transform two sets of coordinates are studied and distortions in geodetic networks are investigated. Commonly used transformation models are first reviewed and most of them are interpreted. Differences between various models are discussed. Pitfalls in partial solutions are then considered. It is shown that only as many chords and/or directional elements can be used in the computation as are needed to completely determine the size or shape of the polyhedron implied in the set of Cartesian coordinates. Each additional element causes the normal matrix to be singular provided that all correlations between the chords are used. A number of tables and maps indicating distortions in the NAD 27, Precise Traverse M-R '72, AUS, and SAD 69 geodetic datums are also included. The residuals of the coordinates are scanned for systematic patterns after transforming each geodetic system to the NWL9D Doppler system. Also, an attempt is made to show scale distortions in the NAD 27.

Leick, Alfred↗

NASA NTRS1975

Theory and applications survey of decentralized control methods

A nonmathematical overview is presented of trends in the general area of decentralized control strategies which are suitable for hierarchical systems. Advances in decentralized system theory are closely related to advances in the so-called stochastic control problem with nonclassical information pattern. The basic assumptions and mathematical tools pertaining to the classical stochastic control problem are outlined. Particular attention is devoted to pitfalls in the mathematical problem formulation for decentralized control. Major conclusions are that any purely deterministic approach to multilevel hierarchical dynamic systems is unlikely to lead to realistic theories or designs, that the flow of measurements and decisions in a decentralized system should not be instantaneous and error-free, and that delays in information exchange in a decentralized system lead to reasonable approaches to decentralized control. A mathematically precise notion of aggregating information is not yet available.

Athans, M.↗

NASA NTRS1977

Reduced variable technique for predicting grain behavior

The use of reduced variables to account for the time-temperature dependence of the relaxation modulus is a standard and universally adopted technique in the stress analysis of solid propellant grains. Recent work has suggested that the reduced variable technique can also be used to account for the dependence of the relaxation modulus on the crosslink density of an elastomer system. By combining variables, it is now possible to determine the relaxation modulus as a function of both mechanical and chemical parameters over a long period of time. The problems involved, the pitfalls to be avoided, and suggested techniques to be used in acquiring data are discussed.

Lewis, G. W.↗

NASA NTRS1977

Flow phenomena peculiar to calculation of compressible turbulent boundary layers

Calculation procedures for compressible turbulent boundary layers were based upon techniques, modeling constants, etc., developed originally for the low speed case. Significant differences and new or altered physics which occur in the compressible case were considered, as compared with the low speed situation. Possible pitfalls and sources of inaccuracy in the calculations were indicated.

Source record↗

NASA NTRS1977

Assessing the future of air freight

The role of air cargo in the current transportation system in the United States is explored. Methods for assessing the future role of this mode of transportation include the use of continuous-time recursive systems modeling for the simulation of different components of the air freight system, as well as for the development of alternative future scenarios which may result from different policy actions. A basic conceptual framework for conducting such a dynamic simulation is presented within the context of the air freight industry. Some research needs are identified and recommended for further research. The benefits, limitations, pitfalls, and problems usually associated with large scale systems models are examined.

Dajani, J. S.↗

NASA NTRS1977

A critical evaluation of the application of amino acid racemization to geochronology and geothermometry

Attempts have been made to determine the age of biological samples by measuring the racemization of amino acids in protein samples. The pitfalls and inherent complications in diagenetic racemization studies are reviewed, and recent advances in improving techniques are outlined. Methodological topics include isolation of amino acids from geological samples, resolution of amino acid enantiomers, and the effects of acid hydrolysis. The theory and kinetics of amino acid racemization are discussed with attention to the derivation of the rate expression for amino acid racemization, isoleucine and the equilibrium constant, the mechanism of amino acid racemization, the racemization of 'bound' versus 'free' amino acids, and factors affecting the racemization rates of free amino acids in aqueous solution. Applications of amino acid racemization kinetics to geochronology is considered with reference to shells, marine sediments, and bones. Potential complications include heating and diagenesis, diagenetic formation of amino acids, the effect of clays, species effect, and contamination.

Williams, K. M.↗

NASA NTRS1978

An orbital service module systems concept

An Orbital Service Module (OSM) system represents a concept for an evolutionary program that will provide utilities services such as electrical power, heat rejection, attitude control, and communications to support payload operations in both Shuttle-tended and untended (free-flyer) modes. The initial program step is a Space Transportation System (STS) power extension package (a solar array system carried by the Orbiter and deployed by the remote manipulator system). The power extension package (PEP) develops the major components of the more sophisticated OSM vehicles. Major objectives of such an approach are (1) the continuous matching of a capability to meet real needs while avoiding the pitfalls usually associated with the uncertainties inherent in long-range prediction of future requirements, and (2) the economies attendant with program continuity and hardware commonality. The initial Orbiter-carried PEP and several later OSM system growth options are discussed.

Craig, J. W.↗

NASA NTRS1978

The use of ground magnetograms to time the onset of magnetospheric substorms

A critical review of magnetospheric substorm timing techniques is presented. Attention is given to substorm timing with auroral zone magnetograms, substorm onset timing with midlatitude magnetograms, multiple onset substorms, and a phenomenological model for multiple onset substorms. Emphasis is placed on some pitfalls that have led some investigators to err in substorm onset determinations. In particular, multiple onset substorms appear to account for many of the reported discrepancies in substorm timing. It is suggested that present idealized models of substorm morphology must be modified to include the multiple onset substorms.

Mcpherron, R. L.↗

NASA NTRS1980

Adaptation and optimization of a line-by-line radiative transfer program for the STAR-100 (STARSMART)

A program to calculate upwelling infrared radiation was modified to operate efficiently on the STAR-100. The modified software processes specific test cases significantly faster than the initial STAR-100 code. For example, a midlatitude summer atmospheric model is executed in less than 2% of the time originally required on the STAR-100. Furthermore, the optimized program performs extra operations to save the calculated absorption coefficients. Some of the advantages and pitfalls of virtual memory and vector processing are discussed along with strategies used to avoid loss of accuracy and computing power. Results from the vectorized code, in terms of speed, cost, and relative error with respect to serial code solutions are encouraging.

Rarig, P. L.↗

NASA NTRS1980

The use of the principle of superposition in measuring and predicting the thermal characteristics of an electronic equipment operated in a space environment

The advantages and possible pitfalls of using a generalized method of measuring and, based on these measurements, predicting the transient or steady-state thermal response characteristics of an electronic equipment designed to operate in a space environment are reviewed. The method requires generation of a set of thermal influence coefficients by test measurement in vacuo. A implified thermal mockup isused in this test. Once this data set is measured, temperatures resulting from arbitrary steady-state or time varying power profiles can be economically calculated with the aid of a digital computer.

Gale, E. H.↗

NASA NTRS1980

Preparation and evaluation of advanced electrocatalysts for phosphoric acid fuel cells

Alloy electrocatalysts on carbon supports were developed for hydrogen oxidation in the presence of carbon monoxide. These electrocatalysts match the best platinum on carbon catalysts for performance yet cost half as much. The results demonstrate that a significant reduction in anode electrocatalyst material cost can be achieved by replacing the platinum. Since surface characterization of this catalyst is important to explain its performance, several approaches and pitfalls to the elucidation of the surface characterization are presented.

Stonehart, P.↗