On systems of orthogonal functions
Hilberts method of solving linear integral equations using system of orthogonal functions
LINEAR EQUATION↗
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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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NSVZ Relation and the Dimensional Reduction in N = 1 SQED
It is known that factorization of the β-function loop integrals into integrals of double total derivatives is an important ingredient needed for deriving the NSVZ relation by direct perturbative calculations in N=1 SQED regularized by thehigher derivatives. It allows to relate the β-function and the anomalous dimension of the matter superfields defined in terms of the bare coupling constant. In this work we find the analog of this result in the case of using dimensional reduction regularization in the lowest orders. However, we demonstrate that in this case the NSVZ relation is not satisfied for the RG functions defined in terms of the bare coupling constant. Nevertheless, it is possible to impose boundary conditions to the renormalization constants determining the NSVZ scheme in the three-loop order for the RG functions defined in terms of the renormalized coupling constant.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
An Intelligent Strain Gauge with Debond Detection and Temperature Compensation
The harsh rocket propulsion test environment will expose any inadequacies associated with preexisting instrumentation technologies, and the criticality for collecting reliable test data justifies investigating any encountered data anomalies. Novel concepts for improved systems are often conceived during the high scrutiny investigations by individuals with an in-depth knowledge from maintaining critical test operations. The Intelligent Strain Gauge concept was conceived while performing these kinds of activities. However, the novel concepts are often unexplored even if it has the potential for advancing the current state of the art. Maturing these kinds of concepts is often considered to be a tangential development or a research project which are both normally abandoned within the propulsion-oriented environment. It is also difficult to justify these kinds of projects as a facility enhancement because facility developments are only accepted for mature and proven technologies. Fortunately, the CIF program has provided an avenue for bringing the Intelligent Strain Gauge to fruition. Two types of fully functional smart strain gauges capable of performing reliable and sensitive debond detection have been successfully produced. Ordinary gauges are designed to provide test article data and they lack the ability to supply information concerning the gauge itself. A gauge is considered to be a smart gauge when it provides supplementary data relating other relevant attributes for performing diagnostic function or producing enhanced data. The developed strain gauges provide supplementary signals by measuring strain and temperature through embedded Karma and nickel chromium (NiCr) alloy elements. Intelligently interpreting the supplementary data into valuable information can be performed manually, however, integrating this functionality into an automatic system is considered to be an intelligent gauge. This was achieved while maintaining a very low mass. The low mass enables debond detection and temperature compensation to be performed when the gauge is utilized on small test articles. It was also found that the element's mass must be relatively small to avoid overbearing the desired thermal dissipation characteristics. Detecting the degradation of a gauge s bond was reliably achieved by correlating thermal dissipation with the bond s integrity. This was accomplished by precisely coupling a NiCr element with a Karma element for accurately interjecting and quantifying thermal energy. A finite amount of thermal energy is consistently placed in the gauge by electrically powering the NiCr element. The energy will only be temporarily stored before it begins to dissipate into the surrounding structure through the gauge bond. The ability to transmit the energy into the structure becomes greatly inhibited by any discontinuity in the bond s substrate. Therefore, the way the thermal dissipation occurs will reveal even the slightest change in the integrity of the bond.
Jensen, Scott L.↗
Development of massively parallel quantum chemistry program SMASH
A massively parallel program for quantum chemistry calculations SMASH was released under the Apache License 2.0 in September 2014. The SMASH program is written in the Fortran90/95 language with MPI and OpenMP standards for parallelization. Frequently used routines, such as one- and two-electron integral calculations, are modularized to make program developments simple. The speed-up of the B3LYP energy calculation for (C{sub 150}H{sub 30}){sub 2} with the cc-pVDZ basis set (4500 basis functions) was 50,499 on 98,304 cores of the K computer.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Integral method in compressible laminar boundary layers and its application.
Properties of compressible boundary layers with heat transfer and arbitrary pressure gradients calculated, using integral equation and correlation concept for application in hypersonic flows
HYPERSONIC FLOW↗
Rough Surfaces: Is the Dark Stuff Just Shadow?: "Who knows what evil lurks in the hearts of men? The shadow knows!"
Remote observations of the surfaces of airless planetary objects are fundamental to inferring the physical structure and compositional makeup of the surface material. A number of forward models have been developed to reproduce the photometric behavior of these surfaces, based on specific, assumed structural properties such as macroscopic roughness and associated shadowing. Most work of this type is applied to geometric albedos, which are affected by complicated effects near zero phase angle that represent only a tiny fraction of the net energy reflected by the object. Other applications include parameter fits to resolved portions of some planetary surface as viewed over a range of geometries. The spherical albedo of the entire object (when it can be determined) captures the net energy balance of the particle more robustly than the geometric albedo. In most treatments involving spherical albedos, spherical albedos and particle phase functions are often treated as if they are independent, neglecting the effects of roughness. In this paper we take a different approach. We note that whatever function captures the phase angle dependence of the brightness of a realistic rough, shadowed, flat surface element relative to that of a smooth granular surface of the same material, it is manifested directly in both the integral phase function and the spherical albedo of the object. We suggest that, where broad phase angle coverage is possible, spherical albedos may be easily corrected for the effects of shadowing using observed (or assumed) phase functions, and then modeled more robustly using smooth-surface regolith radiative transfer models without further imposed (forward-modeled) shadowing corrections. Our approach attributes observed "power law" phase functions of various slope (and "linear" ranges of magnitude-vs.-phase angle) to shadowing, as have others, and goes on to suggest that regolith-model-based inferences of composition based on shadow-uncorrected spherical albedos overestimate the amount of absorbing material contained in the regolith.
geometric albedos↗
Stochastic stellar cluster initial mass functions: Models and impact on integrated cluster parameter determination
Stellar clusters are regularly used to study the evolution of their host galaxy. Except for a few nearby galaxies, these studies rely on the interpretation of integrated cluster properties, especially integrated photometry observed using multiple filters (i.e., the spectral energy distribution, SED). To allow interpretation of such observations, we present a large set of GALEV cluster models using the realistic approach of adopting stochastically sampled stellar initial mass functions. We provide models for a wide range of cluster masses (10{sup 3}-2 × 10{sup 5} M {sub ☉}), metallicities (–2.3 ≤ [Fe/H] ≤ +0.18 dex), foreground extinction, and 184 regularly used filters. We analyze various sets of stochastic cluster SEDs by fitting them with non-stochastic models, which is the procedure commonly used in this field. We identify caveats and quantify the fitting uncertainties associated with this standard procedure. We show that this can yield highly unreliable fitting results, especially for low-mass clusters.
79 ASTRONOMY AND ASTROPHYSICS↗
Geospatial Information, Metadata, and Maps for Global River Corridor Science Focus Area Sites (v5)
This dataset provides geospatial information, metadata, and maps for the Pacific Northwest National Laboratory (PNNL) River Corridor Science Focus Area (RC-SFA; https://www.pnnl.gov/projects/river-corridor) sites. The RC-SFA works to transform understanding of spatial and temporal dynamics in river corridor hydrobiogeochemical functions from molecular reaction to watershed and basin scales. The knowledge we gain is used to formulate and test hypotheses and to improve mechanistic representation of river corridor processes and their response to disturbances in multiscale models of integrated hydrobiogeochemical function. The data provided includes Site ID, latitude, longitude, stream name, and common ID (COMID) for sites used across the RC-SFA. The COMID can be used to find and download data from NHDPlus (https://www.epa.gov/waterdata/nhdplus-national-hydrography-dataset-plus) and other platforms. The sites included are non-exhaustive. Sites (including past sites) will be added to this data package in the future. Data generated from the RC SFA can be accessed at https://data.ess-dive.lbl.gov/portals/PNNLRiverCorridorSFA. This data package was originally published in April 2023. It was updated in June 2023 (v2; modified files), December 2023 (v3; modified files), January 2025 (v4; modified files), and December 2025 (v5; modified files). See the change history section in the readme for more details. This dataset is comprised of one main data folder. The data folder consists of (1) file-level metadata; (2) data dictionary; (3) readme; (4) methods codes; (5) geospatial information for all RC SFA sites including International Generic Sample Number (IGSN); (6) maps of all sites and sites in Washington State, USA; and (7) a subfolder with the shapefile of all sites. All files are .csv, .pdf, .shp, .cpg, .dbf, .prj, .qmd, or .shx. We thank the Confederated Tribes and Bands of the Yakama Nation for access to field locations where some data were collected in Washington state. We also thank the Yakama Nation Tribal Council and Yakama Nation Fisheries for working with us to facilitate sample collection and optimization of data usage according to their values and worldview.
54 ENVIRONMENTAL SCIENCES↗
Nanoconfined Interfaces for Highly Selective Separation of Critical Rare Earth Elements
Industrial demand for rare earth elements (REEs) has surged over the past three decades due to their unique properties that support sustainable energy and new technologies. Separating individual REEs is challenging and hazardous, typically done through liquid-liquid extraction. There is an urgent need for environmentally friendly and efficient separation technologies for REEs. Porous materials offer promising advances for sustainable REE separation via ion-selective capture. We hypothesize that REE separation can be efficiently achieved in reactive nanopores, such as Zr(IV) and Cr(III) metal-organic frameworks (MOFs), through surface functionalization. By integrating material synthesis, interfacial chemistry experiments, theory, computation, and machine learning, we gained insights into the chemical factors controlling REE speciation and their competitive adsorption on MOFs. Our findings show that these materials’ selectivity can be tuned by surface functionalization. The machine learning component addressed ion-specific diffusion based on MOF topology and chemistry.
36 MATERIALS SCIENCE↗
Exchange integrals in magnetoelectric hexagonal ferrite (SrCo{sub 2}Ti{sub 2}Fe{sub 8}O{sub 19}): A density functional study
The exchange integrals in magnetoelectric hexagonal ferrite SrCo{sub 2}Ti{sub 2}Fe{sub 8}O{sub 19} have been calculated by using density functional theory. To get 10 inter-sublattice and 3 intra-sublattice exchange integrals, the electronic structures and total energies of 20 spin arrangements have been calculated with General Gradient Approximation (GGA) + U method. The dependence of exchange integrals on U has been studied. The comparison between the exchange integrals in SrFe{sub 12}O{sub 19} and those in SrCo{sub 2}Ti{sub 2}Fe{sub 8}O{sub 19} shows that substitution of Co and Ti decreases the most interactions involving the 12 k sites. The investigation based on our exchange integrals indicates that magnetic interaction between R and S blocks reduces significantly in SrCo{sub 2}Ti{sub 2}Fe{sub 8}O{sub 19}.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Two-dimensional multifunctional materials from endohedral fullerenes
A multifunctional two-dimensional (2D) material is theoretically predicted based on systematic ab initio calculations and model simulations for the honeycomb lattice of endohedral fullerene W@C 28 molecules. It has structural bistability, ferroelectricity, multiple magnetic phases, and excellent valley characters and can be easily functionalized by the proximity effect with magnetic isolators such as MnTiO 3 . Furthermore, we may also manipulate the valley Hall and spin transport properties by selectively switching a few W@C 28 molecules to the metastable phase. These conclusions contribute to integrating different functions in a single 2D material for technological innovations.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Geometrical approach to neural net control of movements and posture
In one approach to modeling brain function, sensorimotor integration is described as geometrical mapping among coordinates of non-orthogonal frames that are intrinsic to the system; in such a case sensors represent (covariant) afferents and motor effectors represent (contravariant) motor efferents. The neuronal networks that perform such a function are viewed as general tensor transformations among different expressions and metric tensors determining the geometry of neural functional spaces. Although the non-orthogonality of a coordinate system does not impose a specific geometry on the space, this "Tensor Network Theory of brain function" allows for the possibility that the geometry is non-Euclidean. It is suggested that investigation of the non-Euclidean nature of the geometry is the key to understanding brain function and to interpreting neuronal network function. This paper outlines three contemporary applications of such a theoretical modeling approach. The first is the analysis and interpretation of multi-electrode recordings. The internal geometries of neural networks controlling external behavior of the skeletomuscle system is experimentally determinable using such multi-unit recordings. The second application of this geometrical approach to brain theory is modeling the control of posture and movement. A preliminary simulation study has been conducted with the aim of understanding the control of balance in a standing human. The model appears to unify postural control strategies that have previously been considered to be independent of each other. Third, this paper emphasizes the importance of the geometrical approach for the design and fabrication of neurocomputers that could be used in functional neuromuscular stimulation (FNS) for replacing lost motor control.
Review↗
Embedded-cluster calculations in a numeric atomic orbital density-functional theory framework
We integrate the all-electron electronic structure code FHI-aims into the general ChemShell package for solid-state embedding quantum and molecular mechanical (QM/MM) calculations. A major undertaking in this integration is the implementation of pseudopotential functionality into FHI-aims to describe cations at the QM/MM boundary through effective core potentials and therewith prevent spurious overpolarization of the electronic density. Based on numeric atomic orbital basis sets, FHI-aims offers particularly efficient access to exact exchange and second order perturbation theory, rendering the established QM/MM setup an ideal tool for hybrid and double-hybrid level density functional theory calculations of solid systems. We illustrate this capability by calculating the reduction potential of Fe in the Fe-substituted ZSM-5 zeolitic framework and the reaction energy profile for (photo-)catalytic water oxidation at TiO{sub 2}(110)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Combinatorial Sensor Design in Caulobacter crescentus for Selective Environmental Uranium Detection
The ability to detect uranium (U) through environmental monitoring is of critical importance for informing water resource protection and nonproliferation efforts. Although technologies exist for environmental U detection, wide-area environmental monitoring, i.e. sampling coverage over large areas not known to possess U contamination, remains a challenging prospect that necessitates the development of novel detection approaches. In this work, we describe the development of a whole-cell U sensor by integrating two functionally independent, native U-responsive two-component signaling systems (TCS), UzcRS and UrpRS, within an AND gate circuit in the bacterium Caulobacter crescentus. Through leverage of the distinct but imperfect selectivity profiles of both TCS, this combinatorial approach enabled greater selectivity relative to a prior biosensor developed with UzcRS alone; no cross-reactivity was observed with most common environmental metals (e.g, Fe, As, Cu, Ca, Mg, Cd, Cr, Al) or the U decay-chain product Th, and the selectivity against Zn and Pb was significantly improved. In addition, integration of the UzcRS signal amplifier protein UzcY within the AND gate circuit further enhanced overall sensitivity and selectivity for U. The functionality of the sensor in an environmental context was confirmed by detection of U concentrations as low as 1 μM in groundwater samples. The results illustrate the value of a combinatorial approach for constructing whole-cell sensors for the selective detection of analytes for which there are no known evolved regulators.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
A high-order integral solver for scalar problems of diffraction by screens and apertures in three-dimensional space
We present a novel methodology for the numerical solution of problems of diffraction by infinitely thin screens in three-dimensional space. Our approach relies on new integral formulations as well as associated high-order quadrature rules. The new integral formulations involve weighted versions of the classical integral operators related to the thin-screen Dirichlet and Neumann problems as well as a generalization to the open-surface problem of the classical Calderón formulae. The high-order quadrature rules we introduce for these operators, in turn, resolve the multiple Green function and edge singularities (which occur at arbitrarily close distances from each other, and which include weakly singular as well as hypersingular kernels) and thus give rise to super-algebraically fast convergence as the discretization sizes are increased. When used in conjunction with Krylov-subspace linear algebra solvers such as GMRES, the resulting solvers produce results of high accuracy in small numbers of iterations for low and high frequencies alike. We demonstrate our methodology with a variety of numerical results for screen and aperture problems at high frequencies—including simulation of classical experiments such as the diffraction by a circular disc (featuring in particular the famous Poisson spot), evaluation of interference fringes resulting from diffraction across two nearby circular apertures, as well as solution of problems of scattering by more complex geometries consisting of multiple scatterers and cavities.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
High-order cumulants and correlation functions near the critical point from molecular dynamics
We present a systematic investigation of particle-number fluctuations in the crossover region near the critical end point of a first-order phase transition using molecular dynamics simulations of the classical Lennard-Jones fluid. We extend our prior studies to third- and fourth-order cumulants in both coordinate- and momentum-space acceptances and integrated correlation functions (factorial cumulants). We find that, even near the critical point, non-Gaussian cumulants equilibrate on timescales comparable to those of the second-order cumulants, but show stronger finite-size effects. The presence of interactions and of the critical point leads to strong deviations of the cumulants from the ideal-gas baseline in coordinate space; these deviations are expected to persist in momentum space in the presence of collective expansion. In particular, the kurtosis becomes strongly negative, κσ 2 ≪ − 1 , on the crossover side of the critical point. However, this signal is significantly diluted once an efficiency cut used to distinguish protons from baryons is applied, leading to |κσ 2 | ≲ 1 even in the presence of the critical point. We discuss our results in the context of ongoing measurements of proton-number cumulants in heavy-ion collisions in RHIC-BES-II.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
A Boundary Scan Test Vehicle for Direct Chip Attach Testing
To facilitate the new faster, better and cheaper spacecraft designs, smaller more mass efficient avionics and instruments are using higher density electronic packaging technologies such as direct chip attach (DCA). For space flight applications, these technologies need to have demonstrated reliability and reasonably well defined fabrication and assembly processes before they will be accepted as baseline designs in new missions. As electronics shrink in size, not only can repair be more difficult, but 49 probing" circuitry can be very risky and it becomes increasingly more difficult to identify the specific source of a problem. To test and monitor these new technologies, the Direct Chip Attach Task, under NASA's Electronic Parts and Packaging Program (NEPP), chose the test methodology of boundary scan testing. The boundary scan methodology was developed for interconnect integrity and functional testing at hard to access electrical nodes. With boundary scan testing, active devices are used and failures can be identified to the specific device and lead. This technology permits the incorporation of "built in test" into almost any circuit and thus gives detailed test access to the highly integrated electronic assemblies. This presentation will describe boundary scan, discuss the development of the boundary scan test vehicle for DCA and current plans for testing of direct chip attach configurations.
Parsons, Heather A.↗
High-resolution structure of the Escherichia coli ribosome
Protein synthesis by the ribosome is highly dependent on the ionic conditions in the cellular environment, but the roles of ribosome solvation remain poorly understood. Moreover, the function of modifications to ribosomal RNA and ribosomal proteins are unclear. Here we present the structure of the Escherichia coli 70S ribosome to 2.4 Å resolution. The structure reveals details of the ribosomal subunit interface that are conserved in all domains of life, and suggest how solvation contributes to ribosome integrity and function. The structure also suggests how the conformation of ribosomal protein uS12 likely impacts its contribution to messenger RNA decoding. In conclusion, this structure helps to explain the phylogenetic conservation of key elements of the ribosome, including posttranscriptional and posttranslational modifications and should serve as a basis for future antibiotic development.
59 BASIC BIOLOGICAL SCIENCES↗