Applications Technology Satellite, ATS F and G, phase B and C Final report
System analysis and tradeoffs, spacecraft subsystems, and development of ATS 7 satellite
Source record↗
SEARCH · Engineering Papers
Results for “C++ analysis”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Conical isogrid adapter structural test results. Appendix C: Cylindrical isogrid structures
Analysis techniques and data for evaluating the load carrying capabilities of cylindrical isogrid structures subjected to compression and body bending loads are presented. Structural tests were conducted on a 120-inch diameter by 37-inch long cylindrical adapter. Photographs and drawings of the flanged isogrid adapter structure are included. The subjects considered are: (1) summary of the test data resulting from structural analysis, (2) techniques for predicting local and general instability, (3) a method for predicting extended local instability, (4) the effects of basic parameter and constant variations in extended local stability analysis, and (5) evaluation of effective skin width and compression buckling of skin panels on the basis of test data.
Source record↗
An analysis of the adaptability of Loran-C to air navigation
The sources of position errors characteristics of the Loran-C navigation system were identified. Particular emphasis was given to their point on entry as well as their elimination. It is shown that the ratio of realized accuracy to theoretical accuracy of the Loran-C is highly receiver dependent.
Littlefield, J. A.↗
Data analysis and theoretical studies for atmospheric Explorer C, D and E
The research concentrated on construction of a comprehensive model of the chemistry of the ionosphere. It proceeded by comparing detailed predictions of the atmospheric parameters observed by the instrumentation on board the Atmospheric Explorer Satellites with the measured values and modifying the chemistry to bring about consistency. Full account was taken of laboratory measurements of the processes identified as important. The research programs were made available to the AE team members. Regularly updated tables of recommended values of photoionization cross sections and electron impact excitation and ionization cross sections were provided. The research did indeed lead to a chemistry model in which the main pathways are quantitatively secure. The accuracy was sufficient that remaining differences are small.
Dalgarno, A.↗
Toward Complete Isotopic Analysis of Individual Presolar Silicon Carbide Grains: C, N, Si, Sr, Zr, Mo, and Ba in Single Grains of Type X
The isotopic compositions of Sr, Ba, Zr and Mo in single presolar SiC grains from supernovae are different from those expected from either of the dominant heavy element neutron capture nucleosynthesis mechanisms, the s-process and the r-process.
Pellin, M. J.↗
Exploring Carbon Mineral Systems: Recent Advances in C Mineral Evolution, Mineral Ecology, and Network Analysis
Large and growing data resources on the spatial and temporal diversity and distribution of the more than 400 carbon-bearing mineral species reveal patterns of mineral evolution and ecology. Recent advances in analytical and visualization techniques leverage these data and are propelling mineralogy from a largely descriptive field into one of prediction within complex, integrated, multidimensional systems. These discoveries include: (1) systematic changes in the character of carbon minerals and their networks of coexisting species through deep time; (2) improved statistical predictions of the number and types of carbon minerals that occur on Earth but are yet to be discovered and described; and (3) a range of proposed and ongoing studies related to the quantification of network structures and trends, relation of mineral “natural kinds” to their genetic environments, prediction of the location of mineral species across the globe, examination of the tectonic drivers of mineralization through deep time, quantification of preservational and sampling bias in the mineralogical record, and characterization of feedback relationships between minerals and geochemical environments with microbial populations. These aspects of Earth’s carbon mineralogy underscore the complex coevolution of the geosphere and biosphere and highlight the possibility for scientific discovery in Earth and planetary systems.
Carbon↗
Anisotropic magnetocaloric effect and critical behavior in CrCl 3
We report anisotropic magnetocaloric effect and magnetic critical behavior in the van der Waals crystal CrCl 3 . The maximum magnetic entropy change $-ΔS^{max}_M ~ 14.6 J kg -1 K -1 and the relative cooling power RCP ~ 340.3 J kg -1 near T c with a magnetic field change of 5 T are much larger when compared to CrI 3 or CrBr 3 . The rescaled ΔS M (T, H) curves collapse onto a universal curve, confirming the second-order ferromagnetic transition. Finally, further critical behavior analysis around T c presents a set of critical exponents β = 0.28 (1) with T c = 19.4 (2) K, γ = 0.89 (1) with T c = 18.95 (8) K, and δ = 4.6 (1) at T c = 19 K , which are close to those of the theoretical tricritical mean-field model.
2-dimensional systems↗
The millimeter- and submillimeter-wave spectrum of (C-13)H3OH revisited
A total of 245 previously unobserved millimeter- and submillimeter-wave transitions of (C-13)H3OH for J not above 10 were assigned on the basis of measurements with a spectrometer which uses 40-60 GHz klystrons as fundamental radiation sources. These transitions were combined with the previously assigned 596 transitions and were analyzed using a modified internal-axis-method model which treats the symmetric (A) and degenerate (E) substates separately. As a result of the expansion of the (C-13)H3OH data set to cover the same range as the data set of a previous (C-12)H3OH analysis by Anderson et al. (1990), rigid criteria of self-consistency could be applied for the selection and the value of the constants between the isotopic species. The spectral constants obtained were used to make accurate predictions of 562 additional transitions of (C-13)H3OH for v(t) = 0, 1, 2 and rotational quantum number J equal to or less than 12.
Anderson, Todd↗
Investigating the Cuprates as a platform for high-order Van Hove singularities and flat-band physics
Abstract Beyond the two-dimensional saddle-point Van Hove singularities (VHSs) with logarithmic divergences in the density of states, recent studies have identified higher-order VHSs with faster-than-logarithmic divergences that can amplify electron correlation effects. Here we show that the cuprate high-Tc superconductors harbor high-order VHSs in their electronic spectra and unveil a new correlation that the cuprates with high-order VHSs display higher T c ’s. Our analysis indicates that the normal and higher-order VHSs can provide a straightforward new marker for identifying propensity of a material toward the occurrence of correlated phases such as the excitonic insulators and supermetals. Our study suggests cuprates and related high-T c superconductors as materials for exploring the interplay between high-order VHSs, superconducting transition temperatures, and electron correlation effects.
Markiewicz, Robert S. (ORCID:0000000207470713)↗
Ship Radar Observations of a Developing Hurricane in the East Pacific
During the recently completed East Pacific Investigation of Climate Processes in the Coupled Ocean-Atmosphere System (EPIC) field program, the NOAA research vessel Ronald H. Brown (RHB) was deployed in the east Pacific Inter Tropical Convergence Zone (ITCZ) for approximately 3 weeks near 10 deg. N, 95 deg. W. One of the principal objectives of the EPIC-ITCZ program was to observe the modulation of convection by synoptic-scale easterly waves and the air-sea coupling process in this poorly sampled region of the east Pacific. Data from the experiment will be used as validation to improve forecast models. The RHB carried a variety of platforms during EPIC to sample atmospheric and oceanic phenomena, including a scanning C-band Doppler radar, radiation flux instrumentation, air-sea flux system, Doppler lidar, 35 GHz cloud radar, UHF wind profiler, sea surface temperature (SST) sensors, as well as standard surface meteorological instrumentation and a suite of rain gauges. This presentation will focus on the analysis of C-band radar data that was collected on 10 September, 2001 as the ship passed through an easterly wave which later developed into hurricane Ivo. The ship captured approximately 12 hours of convection associated with the tropical disturbance. During this period, the domain sampled by the radar (approximately 71,000 sq km) contained a significant number of echo features. Specifically, the fraction of the domain containing radar echo above 10 dBZ reached 80% for over 2 hours and remained near 60% for a continuous six hour period. Animation of radar images showed distinct rotation in echo features associated with the easterly wave passage. Despite an approximate 4 C drop in surface air temperature and sustained winds approaching 20 m/ s, the SST remained nearly constant throughout the observation period (approx. 29.5 C). Peak values of latent and sensible heat flux exceeded 400 and 100 W /sq m, respectively. The radar documented the change in precipitation vertical structure as the ship passed through regions of significant convection with echo tops approaching 14 km and 30 dBZ echo tops extending to near 9 km embedded in regions that were predominantly stratiform in nature. Single Doppler retrievals (Extended Velocity Azimuth Display) were conducted continuously at 10-minute resolution for approximately 4 hours in the latter part of the observation period, and documented the transition from convection (low-level convergence, upper level divergence) to stratiform (mid-level convergence sandwiched between upper and lower level divergence) kinematic structure.
Cifelli, Robert↗
In Situ Carbon and Sulfur Isotope Analysis of Archean Organic Matter and Pyrite
Stable isotopic compositions of biologically important elements (e.g., C and S) in sedimentary rocks are valuable biosignatures to the extent that they indicate the presence and variable expression of microbial metabolisms in space and time. Strong interactions between the carbon and sulfur cycles (e.g., via organic matter remineralization during microbial sulfate reduction) make coordinated, in situ C and S isotope analysis by secondary ion mass spectrometry (SIMS) a particularly powerful tool. In rocks ranging in age from 2.7-2.5 Ga, expansions in the ranges of delta C-13 of organic matter and delta S-34 of pyrite likely reflect the increasing influence of oxygenic photosynthesis in the surface ocean (as well as methane and sulfur metabolisms in deeper waters), whereas the large range of mass independent sulfur isotope fractionation (Delta S-33) suggests that the atmosphere remained anoxic until approx 2.4 Gyr ago. We report in situ delta C-13 measurements of organic matter in the approx 2.7-2.6 Ga Carawine Dolomite, Marra Mamba Iron Formation, and Jeerinah, Wittenoom, and Tumbiana Formations, as well as the approx 2.5 Ga Mount McRae Shale. We also report in situ delta S-24 and Delta S-33 measurements of pyrite associated with organic matter in a subset of these samples. In a single square cm sample of the Tumbiana Formation with bulk delta C-13(sub org) of -49.7% (VPDB), two distinct kerogen types have delta C-13 values, measured in situ, consistent with oxygenic photosynthesis (-33%) and methane metabolism (-52%). In a sample from the ABDP-9 core, radiobitumen associated with a uraniferous mineral grain is C-13-enriched by 8% (-26.8%0) relative to average in situ kerogen (-34.9%0) and similar in delta C-13 to solvent extractable hydrocarbons from the Mount McRae Shale (avg delta C-13 = -27.1 %). Average reproducibility for delta C-13 was 0.4% (2 SD) using a 6 micron spot and 0.8% using a 3 micron spot. In situ sulfur isotope analyses of 33 authigenic pyrite grains in 3 samples of the ABDP-9 core using a 10 micron spot (2 SD reproducibility = 0.4% for delta S-34 and -0.1% for Delta S-33) show a range of 28.1 % in delta S-34 (-10.3 to 17.8%) and 13.3%0 in Delta S-33 (-3.8 to 9.5%), whereas the range from 132 bulk analyses across 84 m of core is 19.4% for delta S-34 and 11.5% for Delta S-33. Coordinated, in situ carbon and sulfur isotope analyses in one ABDP-9 sample are shown. In situ values from this kerogen-pyrite association are within 0.1% of the bulk value in the case of delta C-13 and higher by several permil in the case of delta S-34 and Delta S-33. Coordinated in situ carbon and sulfur isotope analyses in rocks deposited during key intervals of environmental change (e.g., the Great Oxidation Event) can refine our understanding of the mode and tempo of change. In Earth's oldest sedimentary rocks, and in extraterrestrial samples, these coordinated in situ analyses may reveal biosignatures in the form of isotopic correlations at the scale of individual microorganisms and their microhabitats.
Williford, K. H.↗
Enantiomeric and Isotopic Analysis of Sugar Derivatives in Carbonaceous Meteorites
Several classes of organic compounds are found in carbonaceous meteorites including amino acids, carboxylic acids, hydroxy acids, purines, and pyrimidines. Such compounds are thought to have been delivered to the early Earth in asteroids and comets and may have played a role in the origin of life. Likewise, sugar derivatives are critical to all known lifeforms. Recent analyses of the Murchison and Murray carbonaceous meteorites revealed a diverse suite of such derivatives, i.e., sugar alcohols, and sugar acids. This presentation will focus primarily on the analysis of individual sugar acids - their enantiomeric and isotopic composition. Analysis of these compounds may reveal the nature of past (or present) meteoritic sugars themselves. For example, if parent sugars decomposed (by well-known mechanisms) to give the present acids, were their enantiomeric ratios preserved? Combined with other evidence, the enantiomeric composition of such compounds as glyceric acid and (especially) rare acids may help to answer such questions. C-13 and D isotope analysis of meteoritic sugar alcohols (glycerol, threitol, ribitol, etc.) as a group revealed that they were indigenous to the meteorite. Preliminary C-13 analysis of glyceric acid shows that it is also extraterrestrial.
Cooper, George↗
Identification of preferred multimodal ligand‐binding regions on IgG1 F C using nuclear magnetic resonance and molecular dynamics simulations
Abstract In this study, the binding of multimodal chromatographic ligands to the IgG1 F C domain were studied using nuclear magnetic resonance and molecular dynamics simulations. Nuclear magnetic resonance experiments carried out with chromatographic ligands and a perdeuterated 15 N‐labeled F C domain indicated that while single‐mode ion exchange ligands interacted very weakly throughout the F C surface, multimodal ligands containing negatively charged and aromatic moieties interacted with specific clusters of residues with relatively high affinity, forming distinct binding regions on the F C . The multimodal ligand‐binding sites on the F C were concentrated in the hinge region and near the interface of the C H 2 and C H 3 domains. Furthermore, the multimodal binding sites were primarily composed of positively charged, polar, and aliphatic residues in these regions, with histidine residues exhibiting some of the strongest binding affinities with the multimodal ligand. Interestingly, comparison of protein surface property data with ligand interaction sites indicated that the patch analysis on F C corroborated molecular‐level binding information obtained from the nuclear magnetic resonance experiments. Finally, molecular dynamics simulation results were shown to be qualitatively consistent with the nuclear magnetic resonance results and to provide further insights into the binding mechanisms. An important contribution to multimodal ligand‐F C binding in these preferred regions was shown to be electrostatic interactions and π–π stacking of surface‐exposed histidines with the ligands. This combined biophysical and simulation approach has provided a deeper molecular‐level understanding of multimodal ligand–F C interactions and sets the stage for future analyses of even more complex biotherapeutics.
Gudhka, Ronak B.↗
Tribological properties and surface chemistry of silicon carbide at temperatures to 1500 C
Silicon carbide surfaces were heated to 1500 C in a vacuum and analyzed at room temperature with X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). The basic unit of the surfaces was considered as a plane of a tetrahedron of either SiC4 and CSi4 composition. AES spectra were obtained from 250-1500 C, with an analysis depth of 1 nm revealed the presence of little Si and mostly graphite. XPS analysis depth was 2 nm or less, and Si was found in the second 1 nm. Sliding friction tests with single-crystal silicon carbide in contact with iron in a vacuum were characterized by a stock-slip value. The coefficient of friction increased with increasing temperature up to 400 C, then decreased with increasing temperature from 400-600 C. Reheating surfaces to 800 C after preheating them to that temperature produced no changes in AES readings. It is concluded that the maximum density of silicon and silicon-carbide is at 800 C, and the higher the sliding temperature, the more metal that is transferred.
Miyoshi, K.↗
Geospatial Method for Computing Supplemental Multi-Decadal U.S. Coastal Land-Use and Land-Cover Classification Products, Using Landsat Data and C-CAP Products
This paper discusses the development and implementation of a geospatial data processing method and multi-decadal Landsat time series for computing general coastal U.S. land-use and land-cover (LULC) classifications and change products consisting of seven classes (water, barren, upland herbaceous, non-woody wetland, woody upland, woody wetland, and urban). Use of this approach extends the observational period of the NOAA-generated Coastal Change and Analysis Program (C-CAP) products by almost two decades, assuming the availability of one cloud free Landsat scene from any season for each targeted year. The Mobile Bay region in Alabama was used as a study area to develop, demonstrate, and validate the method that was applied to derive LULC products for nine dates at approximate five year intervals across a 34-year time span, using single dates of data for each classification in which forests were either leaf-on, leaf-off, or mixed senescent conditions. Classifications were computed and refined using decision rules in conjunction with unsupervised classification of Landsat data and C-CAP value-added products. Each classification's overall accuracy was assessed by comparing stratified random locations to available reference data, including higher spatial resolution satellite and aerial imagery, field survey data, and raw Landsat RGBs. Overall classification accuracies ranged from 83 to 91% with overall Kappa statistics ranging from 0.78 to 0.89. The accuracies are comparable to those from similar, generalized LULC products derived from C-CAP data. The Landsat MSS-based LULC product accuracies are similar to those from Landsat TM or ETM+ data. Accurate classifications were computed for all nine dates, yielding effective results regardless of season. This classification method yielded products that were used to compute LULC change products via additive GIS overlay techniques.
Spruce, J. P.↗
Root exudates shift how N mineralization and N fixation contribute to the plant-available N supply in low fertility soils
Nitrogen (N) availability is a primary constraint to plant productivity, especially in marginal lands with inherently low fertility. Root exudates change with plant nutrient status, and are expected to affect the microbially-mediated N transformations (gross N mineralization vs N fixation) in low fertility soil (low soil organic matter). To explore this possibility, we sampled soils from two monoculture switchgrass (var. Cave-In-Rock) plot with and without N addition at two marginal land sites in Michigan, USA. In a two-week lab incubation, we quantified the effect of different root exudates on gross N mineralization and N fixation by adding simulated root exudates (carbohydrates, organic acids) at a rate of 100 μg C g –1 day –1 . On average, adding carbohydrates to low fertility soil increased the soil respiration by 254%, the dissolved organic carbon (DOC) by 366% and reduced dissolved organic N (DON) by 40%. In contrast, soils receiving organic acids had 159% more soil respiration, 163% higher DOC concentration and the DON concentration increased by 49%. Analysis of the C recovery in measured pools revealed that root exudates C inputs were nearly equivalent to the DOC, microbial biomass carbon (MBC), and soil respiration in sandy soil, but only 45–74% of the root exudate C was recovered in these pools in the sandy loam soil. This suggests that root exudate C may be adsorbed to mineral particles in the sandy loam soil. Soil treated with organic acids had higher gross N mineralization and N immobilization rates than soil with carbohydrates addition. Adding carbohydrates significantly increased the free-living N fixation rates, compared to organic acid addition. Changes in soil pH, and DON induced by root exudate addition had strong association with N transformation rates and N availability. Gross N mineralization produced more plant-available N than N fixation, as evidenced by higher inorganic N concentration in soils receiving organic acids than carbohydrates. Here, by quantifying how different root exudates affect the contribution of N mineralization and N fixation to the plant-available N pool in low fertility soils, this study enhances our understanding of the “C for N” exchange in the plant rhizosphere.
54 ENVIRONMENTAL SCIENCES↗
Modeling Plant Metabolism: From Network Reconstruction to Mechanistic Models
Mathematical modeling of plant metabolism allows the plant science community to understand the organization of plant metabolism, obtain quantitative insights into metabolic functions, and derive engineering strategies for manipulation of metabolism. Among the various modeling approaches, metabolic pathway analysis can dissect the basic functional modes of subsections of core metabolism, such as photorespiration, and reveal how classical definitions of metabolic pathways have overlapping functionality. In current research using constraint-based modeling in plants, numerous computational tools are currently available to analyze large-scale and genome-scale metabolic networks. For 13 C-metabolic flux analysis, principles of isotopic steady state have been used to study heterotrophic plant tissues, while nonstationary isotope labeling approaches are amenable to the study of photoautotrophic and secondary metabolism. Enzyme kinetic models explore pathways in mechanistic detail, and we discuss different approaches to determine or estimate kinetic parameters. In this review, we describe recent advances and challenges in modeling plant metabolism.
59 BASIC BIOLOGICAL SCIENCES↗
Geometrical analysis of Cys-Cys bridges in proteins and their prediction from incomplete structural information
Analysis of C-alpha atom positions from cysteines involved in disulphide bridges in protein crystals shows that their geometric characteristics are unique with respect to other Cys-Cys, non-bridging pairs. They may be used for predicting disulphide connections in incompletely determined protein structures, such as low resolution crystallography or theoretical folding experiments. The basic unit for analysis and prediction is the 3 x 3 distance matrix for Cx positions of residues (i - 1), Cys(i), (i +1) with (j - 1), Cys(j), (j + 1). In each of its columns, row and diagonal vector--outer distances are larger than the central distance. This analysis is compared with some analytical models.
NASA Discipline Exobiology↗