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DOE OSTI2016

Theoretical estimate of the effect of thermal agitation on ribosome motion generated by stochastic microswimming

The effect of thermal agitation on ribosome motion is evaluated through the Péclet number, assuming that the ribosome is self-propelled along the mRNA during protein synthesis by a swimming stroke consisting of a cycle of stochastically-generated ribosome configurations involving its two subunits. The ribosome velocity probability distribution function is obtained, giving an approximately normal distribution. Its mean and variance together with an estimate of the in vivo free diffusion coefficient of the ribosome and using only configuration changes of small size, give a Péclet number similar to motor proteins and microorganisms. These results suggest the feasibility of the stochastic microswimming hypothesis to explain ribosome motion. - Highlights: • Hypothesis: the ribosome swims along the mRNA during protein synthesis. • How can withstand the thermal agitation of the particles in the surrounding fluid? • The Péclet number Pe is calculated estimating the in vivo diffusion coefficient. • With small size deformations the ribosome has speeds similar to motor proteins. • Similar Pe values for the ribosome and the motor proteins mean feasible hypothesis.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2019

Interparticle Interactions in Dilute Solutions of Polyelectrolyte Complex Micelles.

The application of dilute solutions of poly electrolyte complex (PEC) micelles for delivering therapeutic nucleic acids into disease sites has gained momentum. This Letter reports a detailed characterization of PEC micelles in dilute solutions including their internal structures and the determination of the interparticle interactions. The polymer concentration ranges from 0.1 to 0.5 wt %, a regime where micelle-micelle interactions are infrequent. We employ synchrotron small-angle X-ray scattering (SAXS) to simultaneously probe the morphology, internal structure, and radius of gyration (R-g) of the self-assemblies formed by charged diblock polyelectrolytes and homopolyelectrolytes. The emerging appearance of the structure factor in SAXS profiles with the increasing polymer concentration demonstrates the presence of the repulsive intermicellar correlations, which is further confirmed by the differences between the "reciprocal R-g" estimated by Guinier approximation and the "real space R-g" determined by pair distribution functions. We find that the soft corona chains tethered on the surface of phase-separated complex domains are compressed when micelles come close to the point where a hard-sphere interaction takes over. These findings contribute to the fundamental understanding of the structure and space-filling constraints in the complexation-driven self-assemblies and advance the rational design of cationic polymer-based nonviral gene delivery vectors.

Wu, Hao↗

DOE OSTI2026

Qualifying LaBr3:Ce+Sr detector performance for the Mu2e experiment at Fermilab Using the ELBE Accelerator

A LaBr3:Ce+Sr detector will be used to measure the stopped muon captures at the Mu2e experiment at Fermilab. It has been benchmarked in a test beam experiment performed at the ELBE electron accelerator located at the Helmholtz-Zentrum Dresden-Rossendorf, Germany. ELBE’s pulsed bremsstrahlung beam line was set to deliver an average γ -ray energy of between 4–5 MeV. The detector response was mapped to match Mu2e beam conditions, including rates up to 1 Mcps, energy flux, and time structure. A radioactive calibration source was used to mimic the characteristic 1808.7 keV γ -ray, emitted during the atomic muon nuclear capture in the Mu2e aluminum stopping target. The detector energy resolution was measured as a function of the average energy flux: up to 1 TeV/s for 0.34 s, the steady-operation beam-on time and up to 4 TeV/s for 5 ms to get a conservative estimate of the effect of high intensity Mu2e beam fluctuations. The PMT gain variation as a function of the beam spill length and average intensity has been parametrized and corrected for. When a PMT gain correction corresponding to the average beam-spill intensity is applied, the residual effect of beam intensity fluctuations around the average degrades the energy resolution, σ E γ /E γ , at 1808.7 keV from 0.66% to 0.83%.

Huang, Shihua [Purdue U., West Lafayette]↗

DOE OSTI2018

Kinetics of Silicon field evaporation

Highlights: • A theory of field evaporation developed for metals is applied to Silicon. • Potential energy curves and evaporation field strengths are calculated with density functional theory. • Good agreement with experimental results is obtained for Silicon. The theory of field evaporation, previously developed for metals and adsorbates, is applied to semiconductors and insulators, specifically Si. Potential energy curves and evaporation field strengths of Si{sub 6} and Si{sub 7} are calculated with density functional theory. The evaporation field strength is found to be proportional to the coordination. Good agreement with experimental results is obtained for Silicon as well as an estimate of the experimental field strength.

36 MATERIALS SCIENCE↗

DOE OSTI2018

Material and Energy Efficiency: A Framework for Broader Analysis of Energy Use in the U.S. Economy

Energy efficiency analysis has focused predominantly on reducing energy at its point of use by individual components, processes, or products. Efforts to address the energy embodied in materials through strategies and technologies that reduce raw material production - while maintaining the function and use of materials - offer a complementary and expansive approach to traditional energy efficiency analysis. The U.S. Department of Energy (DOE) energy analysis community currently lacks analytical tools that are appropriate for 1) estimating on a product and economy-wide basis energy efficiency potential achieved through material efficiency strategies and 2) evaluating how these new strategies may complement existing energy efficiency efforts. The goal of this report is to describe a standardized analysis framework that would enable calculation of embodied and direct energy and the estimation of energy reduction potential achieved through changes in material use. The proposed framework meets this functionality by spanning the entire U.S. economy, including international trade flows; capturing material and energy use in products and services from raw material extraction to retirement; maintaining material and energy balances; and adjusting dynamically to absolute and relative changes in materials and energy use. The framework is composed of two main elements: a dynamic hybrid input-output (IO) model and a material energy identity. The hybrid IO model defines recipes for material and energy flows in physical (e.g., British thermal units [Btus] and tons) and monetary units, and allows for dynamic adjustments to the amount of materials and energy used. The second element of the analytical framework, the material energy identity, acts as a way of identifying and organizing energy and material efficiency strategies, which are then implemented and analyzed in the hybrid IO model. The report also provides a simple example application of the proposed framework, which illustrates the concept of reducing energy use through changes to material efficiency.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

DOE OSTI2023

pvlib iotools—Open-source Python functions for seamless access to solar irradiance data

Access to accurate solar resource data is critical for numerous applications, including estimating the yield of solar energy systems, developing radiation models, and validating irradiance datasets. However, lack of standardization in data formats and access interfaces across providers constitutes a major barrier to entry for new users. pvlib python’s iotools subpackage aims to solve this issue by providing standardized Python functions for reading local files and retrieving data from external providers. All functions follow a uniform pattern and return convenient data outputs, allowing users to seamlessly switch between data providers and explore alternative datasets. The pvlib package is community-developed on GitHub: https://github.com/pvlib/pvlib-python. As of pvlib python version 0.9.5, the iotools subpackage supports 12 different datasets, including ground measurement, reanalysis, and satellite-derived irradiance data. The supported ground measurement networks include the Baseline Surface Radiation Network (BSRN), NREL MIDC, SRML, SOLRAD, SURFRAD, and the US Climate Reference Network (CRN). Additionally, satellite-derived and reanalysis irradiance data from the following sources are supported: PVGIS (SARAH & ERA5), NSRDB PSM3, and CAMS Radiation Service (including McClear clear-sky irradiance).

14 SOLAR ENERGY↗

DOE OSTI2016

Stereo-particle image velocimetry uncertainty quantification

Particle image velocimetry (PIV) measurements are subject to multiple elemental error sources and thus estimating overall measurement uncertainty is challenging. Recent advances have led to a posteriori uncertainty estimation methods for planar two-component PIV. However, no complete methodology exists for uncertainty quantification in stereo PIV. In the current paper, a comprehensive framework is presented to quantify the uncertainty stemming from stereo registration error and combine it with the underlying planar velocity uncertainties. The disparity in particle locations of the dewarped images is used to estimate the positional uncertainty of the world coordinate system, which is then propagated to the uncertainty in the calibration mapping function coefficients. Next, the calibration uncertainty is combined with the planar uncertainty fields of the individual cameras through an uncertainty propagation equation and uncertainty estimates are obtained for all three velocity components. The methodology was tested with synthetic stereo PIV data for different light sheet thicknesses, with and without registration error, and also validated with an experimental vortex ring case from 2014 PIV challenge. Thorough sensitivity analysis was performed to assess the relative impact of the various parameters to the overall uncertainty. The results suggest that in absence of any disparity, the stereo PIV uncertainty prediction method is more sensitive to the planar uncertainty estimates than to the angle uncertainty, although the latter is not negligible for non-zero disparity. Overall the presented uncertainty quantification framework showed excellent agreement between the error and uncertainty RMS values for both the synthetic and the experimental data and demonstrated reliable uncertainty prediction coverage. Finally, this stereo PIV uncertainty quantification framework provides the first comprehensive treatment on the subject and potentially lays foundations applicable to volumetric PIV measurements.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2016

Technical Note: Statistical dependences between channels in radiochromic film readings. Implications in multichannel dosimetry

Purpose: This note studies the statistical relationships between color channels in radiochromic film readings with flatbed scanners. The same relationships are studied for noise. Finally, their implications for multichannel film dosimetry are discussed. Methods: Radiochromic films exposed to wedged fields of 6 MV energy were read in a flatbed scanner. The joint histograms of pairs of color channels were used to obtain the joint and conditional probability density functions between channels. Then, the conditional expectations and variances of one channel given another channel were obtained. Noise was extracted from film readings by means of a multiresolution analysis. Two different dose ranges were analyzed, the first one ranging from 112 to 473 cGy and the second one from 52 to 1290 cGy. Results: For the smallest dose range, the conditional expectations of one channel given another channel can be approximated by linear functions, while the conditional variances are fairly constant. The slopes of the linear relationships between channels can be used to simplify the expression that estimates the dose by means of the multichannel method. The slopes of the linear relationships between each channel and the red one can also be interpreted as weights in the final contribution to dose estimation. However, for the largest dose range, the conditional expectations of one channel given another channel are no longer linear functions. Finally, noises in different channels were found to correlate weakly. Conclusions: Signals present in different channels of radiochromic film readings show a strong statistical dependence. By contrast, noise correlates weakly between channels. For the smallest dose range analyzed, the linear behavior between the conditional expectation of one channel given another channel can be used to simplify calculations in multichannel film dosimetry.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2025

Multiplicity-dependent jet modification from di-hadron correlations in pp collisions at $ \sqrt{s} $ = 13 TeV

Short-range correlations between charged particles are studied via two-particle angular correlations in pp collisions at $\sqrt{s}$ = 13 TeV. The correlation functions are measured as a function of the relative azimuthal angle ∆φ and the pseudorapidity separation ∆η for pairs of primary charged particles within the pseudorapidity interval |η| < 0.9 and the transverse-momentum range 1 < p T < 8 GeV/c. Near-side (|∆φ| < 1.3) peak widths are extracted from a generalised Gaussian fitted over the correlations in full pseudorapidity separation (|∆η| < 1.8), while the per-trigger associated near-side yields are extracted for the short-range correlations (|∆η| < 1.3). Both are evaluated as a function of charged-particle multiplicity obtained by two different event activity estimators. The width of the near-side peak decreases with increasing multiplicity, and this trend is reproduced qualitatively by the Monte Carlo event generators PYTHIA 8, AMPT, and EPOS. However, the models overestimate the width in the low transverse-momentum region (p T < 3 GeV/c). The per-trigger associated near-side yield increases with increasing multiplicity. Although this trend is also captured qualitatively by the considered event generators, the yield is mostly overestimated by the models in the considered kinematic range. The measurement of the shape and yield of the short-range correlation peak can help us understand the interplay between jet fragmentation and event activity, quantify the narrowing trend of the near-side peak as a function of transverse momentum and multiplicity selections in pp collisions, and search for final-state jet modification in small collision systems.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2020

Conservative Release Fraction Correlation for Spray Releases

Washington River Protection Solutions, LLC (WRPS) is planning to conduct repairs in the Liquid Effluent Retention Facility (LERF), and prior to conducting this work they will re-evaluate the hazard category designation for LERF. As part of this evaluation, WRPS needs estimates of the release fraction of potential accidental sprays, because a spray release is a potential bounding accident. Pacific Northwest National Laboratory previously developed a conservative correlation for the cumulative generation rate (volume per time) of aerosol droplets less than or equal to specific sizes from spray releases as a function of the spray pressure, orifice area, and droplet diameter. To obtain release fraction estimates from the conservative generation rate correlation, the correlation needs to be recast by dividing the aerosol generation rate by the flow rate of a spray. In the current study, a conservative release fraction correlation was developed from the conservative aerosol generation rate correlation developed previously by dividing the generation rate correlation by the flow rate of a spray using an orifice flow rate equation and then this correlation was adjusted to be conservative. Test data were also extrapolated to a lower pressure than the lowest pressure tested (100 psig) for the spray data used for developing the previous conservative generation rate correlation. The new conservative release fraction correlation was then used to predict release fractions of respirable droplets (droplets = 10 µm) for four specific pipes that are part of LERF.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2017

THE LOCAL [C ii] 158 μ m EMISSION LINE LUMINOSITY FUNCTION

We present, for the first time, the local [C ii] 158 μ m emission line luminosity function measured using a sample of more than 500 galaxies from the Revised Bright Galaxy Sample. [C ii] luminosities are measured from the Herschel PACS observations of the Luminous Infrared Galaxies (LIRGs) in the Great Observatories All-sky LIRG Survey and estimated for the rest of the sample based on the far-infrared (far-IR) luminosity and color. The sample covers 91.3% of the sky and is complete at S{sub 60μm} > 5.24 Jy. We calculate the completeness as a function of [C ii] line luminosity and distance, based on the far-IR color and flux densities. The [C ii] luminosity function is constrained in the range ∼10{sup 7–9} L{sub ⊙} from both the 1/ V{sub max} and a maximum likelihood methods. The shape of our derived [C ii] emission line luminosity function agrees well with the IR luminosity function. For the CO(1-0) and [C ii] luminosity functions to agree, we propose a varying ratio of [C ii]/CO(1-0) as a function of CO luminosity, with larger ratios for fainter CO luminosities. Limited [C ii] high-redshift observations as well as estimates based on the IR and UV luminosity functions are suggestive of an evolution in the [C ii] luminosity function similar to the evolution trend of the cosmic star formation rate density. Deep surveys using the Atacama Large Millimeter Array with full capability will be able to confirm this prediction.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2018

Quantifying biogeochemical heterogeneity in soil systems

Soils are increasingly perceived as complex systems with properties and biogeochemical functions that vary on millimeter scales. Quantitative information about the resulting biogeochemical heterogeneity is needed to improve process knowledge and to render biogeochemical models more mechanistic. Here in this work, we demonstrate how standardized arrays of Pt-electrodes can be used to quantify biogeochemical or ‘functional’ soil heterogeneity, defined as the extent to which the soil is subdivided into microenvironments. Our case study confirmed the validity of this approach for a soil sequence consisting of a well-drained, a moderately well drained and a poorly drained Mollisol. We found that (i) variations in soil moisture content are the immediate cause for variations in functional heterogeneity, with (ii) soil porosity influencing rates and the magnitude of change. We posit that the deployment of standardized arrays of Pt-electrodes will offer an affordable option to monitor the general metabolic state of the soil system and simultaneously quantify the functional heterogeneity of underlying processes at any point in time. Such information should be useful to improve quantitative estimates of processes as diverse as trace gas emissions, trace gas consumption, reductive dehalogenation and mobilization of metals in the subsurface biosphere. Lastly, we recommend that parameterization of functional soil heterogeneity be included in long-term soil monitoring programs such as Superfund Sites, Critical Zone Observatories, Long Term Ecological Research (LTER) and National Ecological Observatory Network (NEON) sites.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2017

A practical globalization of one-shot optimization for optimal design of tokamak divertors

In past studies, nested optimization methods were successfully applied to design of the magnetic divertor configuration in nuclear fusion reactors. In this paper, so-called one-shot optimization methods are pursued. Due to convergence issues, a globalization strategy for the one-shot solver is sought. Whereas Griewank introduced a globalization strategy using a doubly augmented Lagrangian function that includes primal and adjoint residuals, its practical usability is limited by the necessity of second order derivatives and expensive line search iterations. In this paper, a practical alternative is offered that avoids these drawbacks by using a regular augmented Lagrangian merit function that penalizes only state residuals. Additionally, robust rank-two Hessian estimation is achieved by adaptation of Powell's damped BFGS update rule. The application of the novel one-shot approach to magnetic divertor design is considered in detail. For this purpose, the approach is adapted to be complementary with practical in parts adjoint sensitivities. Using the globalization strategy, stable convergence of the one-shot approach is achieved.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

DOE OSTI2020

Local self-motion of water through the Van Hove function

Here, we show that the self-part of the Van Hove Function the correlation function describing the dynamics of a single molecule of water can be determined through a high-resolution inelastic X-ray scattering experiment. The measurement of inelastic X-ray scattering up to 10 Å -1 makes it possible to convert the inelastic X-ray scattering spectra into the Van Hove function, and its self-part is extracted from the short-range correlations. The diffusivity estimated from the short-range dynamics of water molecules is different from the long-range diffusivity measured by other methods. This approach using the experimentally determined self-part of the Van Hove function will be useful to the study of the local dynamics of atoms and molecules in liquids.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2022

Parameter estimation from spontaneous imbibition into volcanic tuff

Two-phase fluid flow properties underlie quantitative prediction of water and gas movement, but constraining these properties typically requires multiple time-consuming laboratory methods. The estimation of two-phase flow properties (van Genuchten parameters, porosity, and intrinsic permeability) is illustrated in cores of vitric nonwelded volcanic tuff using Bayesian parameter estimation that fits numerical models to observations from spontaneous imbibition experiments. The uniqueness and correlation of the estimated parameters is explored using different modeling assumptions and subsets of the observed data. The resulting estimation process is sensitive to both moisture retention and relative permeability functions, thereby offering a comprehensive method for constraining both functions. The data collected during this relatively simple laboratory experiment, used in conjunction with a numerical model and a global optimizer, result in a viable approach for augmenting more traditional capillary pressure data obtained from hanging water column, membrane plate extractor, or mercury intrusion methods. This method may be useful when imbibition rather than drainage parameters are sought, when larger samples (e.g., including heterogeneity or fractures) need to be tested that cannot be accommodated in more traditional methods, or when in educational laboratory settings.

58 GEOSCIENCES↗

DOE OSTI2021

Fiducial $q_T$ resummation of color-singlet processes at N$^3$LL+NNLO

We present a framework for $q_T$ resummation at N 3 LL+NNLO accuracy for arbitrary color-singlet processes based on a factorization theorem in SCET. Our implementation CuTe-MCFM is fully differential in the Born kinematics and matches to large-$q_T$ fixed-order predictions at relative order $α^2_s$. It provides an efficient way to estimate uncertainties from fixed-order truncation, resummation, and parton distribution functions. In addition to W ± , Z and H production, also the diboson processes $\gamma\gamma$, Z$\gamma$, ZH and W ± H are available, including decays. We discuss and exemplify the framework with several direct comparisons to experimental measurements as well as inclusive benchmark results. In particular, we present novel results for $\gamma\gamma$ and Z$\gamma\gamma$ at N 3 LL+NNLO and discuss in detail the power corrections induced by photon isolation requirements.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2017

Evidence for presynaptically silent synapses in the immature hippocampus

Silent synapses show NMDA receptor (NMDAR)-mediated synaptic responses, but not AMPAR-mediated synaptic responses. A prevailing hypothesis states that silent synapses contain NMDARs, but not AMPARs. However, alternative presynaptic hypotheses, according to which AMPARs are present at silent synapses, have been proposed; silent synapses show slow glutamate release via a fusion pore, and glutamate spillover from the neighboring synaptic terminals. Consistent with these presynaptic hypotheses, the peak glutamate concentrations at silent synapses have been estimated to be ≪170 μM, much lower than those seen at functional synapses. Glutamate transients predicted based on the two presynaptic mechanisms have been shown to activate only high-affinity NMDARs, but not low-affinity AMPARs. Interestingly, a previous study has developed a new approach to distinguish between the two presynaptic mechanisms using dextran, an inert macromolecule that reduces the diffusivity of released glutamate: postsynaptic responses through the fusion pore mechanism, but not through the spillover mechanism, are potentiated by reduced glutamate diffusivity. Therefore, we reasoned that if the fusion pore mechanism underlies silent synapses, dextran application would reveal AMPAR-mediated synaptic responses at silent synapses. In the present study, we recorded AMPAR-mediated synaptic responses at the CA3-CA1 synapses in neonatal rats in the presence of blockers for NMDARs and GABAARs. Bath application of dextran revealed synaptic responses at silent synapses. GYKI53655, a selective AMPAR-antagonist, completely inhibited the unsilenced synaptic responses, indicating that the unsilenced synaptic responses are mediated by AMPARs. The dextran-mediated reduction in glutamate diffusivity would also lead to the activation of metabotropic glutamate receptors (mGluRs), which might induce unsilencing via the activation of unknown intracellular signaling. Hence, we determined whether mGluR-blockers alter the dextran-induced unsilencing. However, dextran application continued to produce significant synaptic unsilencing in the presence of a cocktail of the blockers for all subtypes of mGluRs. Our findings provide evidence that slowed glutamate diffusion produces synaptic unsilencing by enhancing the peak glutamate occupancy of pre-existing AMPARs, supporting the fusion pore mechanism of silent synapses. - Highlights: • Slowed glutamate diffusion by dextran reveals synaptic responses at silent synapses. • Unsilenced synaptic responses are mediated by AMPA receptors. • Dextran-induced unsilencing is independent of metabotropic glutamate receptors.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2023

Bayesian sequential optimal experimental design for nonlinear models using policy gradient reinforcement learning

We present a mathematical framework and computational methods for optimally designing a finite sequence of experiments. This sequential optimal experimental design (sOED) problem is formulated as a finite-horizon partially observable Markov decision process (POMDP) under a Bayesian setting and with information-theoretic utilities. The formulation is general and may accommodate continuous random variables, non-Gaussian posteriors, and nonlinear forward models. The sOED design policy incorporates elements of feedback and lookahead simultaneously, and we show it to generalize the commonly-used batch and greedy design strategies. We solve for the sOED policy using the policy gradient (PG) method from reinforcement learning, and provide a derivation for the PG expression in the sOED context. Adopting an actor-critic approach, the policy and value functions are parameterized using deep neural networks and improved via PG estimates produced from simulated episodes of designs and observations. The new PG-sOED algorithm is first validated on a linear-Gaussian benchmark, and then compared against other design baselines on a sensor movement problem for contaminant source inversion in a convection-diffusion field. As a result, we provide explanation for the policy behaviors using knowledge of the underlying physical process.

97 MATHEMATICS AND COMPUTING↗