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DOE OSTI2023

Precise Pore Engineering of fcu–Type Y–MOFs for One–Step C 2 H 4 Purification from Ternary C 2 H 6 /C 2 H 4 /C 2 H 2 Mixtures

The purification of C 2 H 4 from C 2 H 6 /C 2 H 4 /C 2 H 2 mixtures is of great significance in the chemical industry for C 2 H 4 production but remains a daunting task. Guided by powerful reticular chemistry principles, herein a systematic study is carried out to engineer pore dimensions and pore functionality of fcu-type Y-based metal–organic frameworks (Y-MOFs) through the construction of a series of eight new structures using linear dicarboxylate linkers with different length and functional groups. This study illustrates how delicate changes in pore size and pore surface chemistry can effectively influence the adsorption preference of C 2 H 6 , C 2 H 4 , and C 2 H 2 by the MOFs. Importantly, clear relations between pore size/pore surface polarity and C 2 adsorption selectivities of this series of MOFs are established. In particular, HIAM-326 built on a linker decorated with trifluoromethoxy group shows notably preferential adsorption of C 2 H 6 and C 2 H 2 over C 2 H 4 , with balanced C 2 H 2 /C 2 H 4 and C 2 H 6 /C 2 H 4 selectivities. Furthermore, this endows the compound with the capability of one-step purification of C 2 H 4 from C 2 H 6 /C 2 H 4 /C 2 H 2 ternary mixtures, which is validated by breakthrough measurements where high purity C 2 H 4 (99.9%+) can be obtained directly from the separation column. Its adsorption thermodynamics and underlying selective adsorption mechanisms are further revealed by ab initio calculations.

36 MATERIALS SCIENCE↗

NASA NTRS1994

Infrared astronomy from the Moon

The purpose of this paper is to exhibit the advantages and limitations to infrared astronomical observations form the moon. The most obvious apparent advantage is the lack of a lunar atmosphere; radiation arriving from the universe is neither extinguished nor refracted as it approaches the lunar surface. However, the Earth's atmosphere's protection against cosmic rays is also lost, and infrared detectors are highly sensitive to irradiation by energetic particles. A second apparent advantage is the relative ease with which beams from an array of telescopes can be interferometrically combined; again the vacuum environment with constant refractive index of unity throughout, permits combination without phase delay across the entire spectral range. But thermal radiation from optical components and stray radiation from the lunar environment, just outside the light path, tend to lessen that advantage, except in narrow-spectral-band spatial interferometry, in which only the radiation in individual spectral lines is mapped, and broad-band thermal emission can be effectively filtered out. On the Moon's night side, and in polar craters on the Moon, radiative cooling should permit the attainment of high sensitivity with large telescopes. Just as the proposed Edison spacecraft primary mirror is expected to reach temperatures around 40 K, so also large lunar primary mirrors might be expected to reach temperatures in that range, making the zodiacal glow the main source of noise at wavelengths shortward of 25 micrometers. The slow rota tion of the Moon, and the lack of vibrations from natural sources such as winds, should provide advantages in guiding on specific astronomical sources. To learn as much as possible about the difficulties of remote observations in a hostile environment, Antarctic observatories should be used as test beds for the rigors of lunar observations. The strenuous requirements for successful astronomical observations from the South Pole are similar to those expected to be encountered in observations conducted from the Moon.

Harwit, Martin↗

DOE OSTI2025

A tale of two polarization paradoxes: The diamagnetic polarization paradox

An accurate calculation of the total polarization charge density in a plasma is essential for a self-consistent determination of the electric field. Yet, the “diamagnetic polarization paradox” refers to the fact that there is a paradoxical factor of 1/2 difference between the pressure-driven “diamagnetic polarization” density calculated using real space drift theory vs action-angle space guiding center and gyrokinetic theory that has not been explained before. Here, we show that both results can be made consistent with one another. Half of the diamagnetic polarization is due to the transformation from the guiding center density to the real space density. The other half is due to the fact that, within the drift kinetic ordering assumptions, the guiding center density should be expressed as the gyroaverage of the density in the limit of vanishing Larmor radius. A comprehensive review of polarization is presented to complete the derivation, and then we derive results that are required for the polarization calculations to agree. Expressions for the diamagnetic polarization density are given that are accurate to first order in amplitude and all orders in gyroradius within the gyrokinetic theory for a constant magnetic field. Applications to Maxwell–Boltzmann particle distribution functions (PDFs), including anisotropic temperature, are presented. Local invariants, like total energy and toroidal momentum, do not generate net polarization effects; the electric and thermodynamic polarizations must precisely cancel. In contrast, anisotropic dependence on the magnetic moment generates a net polarization proportional to the temperature anisotropy. Finally, when sources are present, the equilibrium PDF is approximately the ratio of two orbit averages.

adiabatic theory↗

DOE OSTI2021

Valence shell photoelectron angular distributions and vibrationally resolved spectra of imidazole: A combined experimental–theoretical study

Linearly polarized synchrotron radiation has been used to record polarization dependent valence shell photoelectron spectra of imidazole in the photon energy range 21–100 eV. These have allowed the photoelectron angular distributions, as characterized by the anisotropy parameter β, and the electronic state intensity branching ratios to be determined. Complementing these experimental data, theoretical photoionization partial cross sections and β-parameters have been calculated for the outer valence shell orbitals. The assignment of the structure appearing in the experimental photoelectron spectra has been guided by vertical ionization energies and spectral intensities calculated by various theoretical methods that incorporate electron correlation and orbital relaxation. Strong orbital relaxation effects have been found for the 15a', nitrogen lone-pair orbital. The calculations also predict that configuration mixing leads to the formation of several low-lying satellite states. The vibrational structure associated with ionization out of a particular orbital has been simulated within the Franck–Condon model using harmonic vibrational modes. The adiabatic approximation appears to be valid for the X 2A" state, with the β-parameter for this state being independent of the level of vibrational excitation. However, for all the other outer valence ionic states, a disparity occurs between the observed and the simulated vibrational structure, and the measured β-parameters are at variance with the behavior expected at the level of the Franck–Condon approximation. Furthermore, these inconsistencies suggest that the excited electronic states may be interacting vibronically such that the nuclear dynamics occur over coupled potential energy surfaces.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

The CLAS12 Central Time-of-Flight system

The Central Time-of-Flight system for the large-acceptance CLAS12 spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility is described. The system consists of a hermetic barrel of 48 scintillation counters at a radius of 25 cm from the beamline. The wedge-shaped counters are 3.4 cm wide, 3.0 cm thick, and 90 cm long, and span a range of polar angles relative to the center of the nominal target location from roughly 35° to 125°. The counters reside in the 5-T field of the CLAS12 superconducting solenoid. The bars are read out via bent light guides 1 m long on the upstream end of the counters and 1.6 m long on the downstream end. The phototubes are shielded by a multi-layer dynamical magnetic shield system to reduce the local fringe fields in the range from 400 G to 1000 G down to the level of 0.2 G at the location of the photocathodes. The average effective time resolution of the counters is 80 ps.

47 OTHER INSTRUMENTATION↗

NASA NTRS1995

Feasibility of Coupling Between a Single-Mode Elliptical-Core Fiber and a Single Mode Rib Waveguide Over Temperature

To determine the feasibility of coupling the output of an optical fiber to a rib waveguide in a temperature environment ranging from 20 C to 300 C, a theoretical calculation of the coupling efficiency between the two was investigated. This is a significant problem which needs to be addressed to determine whether an integrated optic device can function in a harsh temperature environment. Because the behavior of the integrated-optic device is polarization sensitive, a polarization-preserving optic fiber, via its elliptical core, was used to couple light with a known polarization into the device. To couple light energy efficiently from an optical fiber into a channel waveguide, the design of both components should provide for well-matched electric field profiles. The rib waveguide analyzed was the light input channel of an integrated-optic pressure sensor. Due to the complex geometry of the rib waveguide, there is no analytical solution to the wave equation for the guided modes. Approximation or numerical techniques must be utilized to determine the propagation constants and field patterns of the guide. In this study, three solution methods were used to determine the field profiles of both the fiber and guide: the effective-index method (EIM), Marcatili's approximation, and a Fourier method. These methods were utilized independently to calculate the electric field profile of a rib channel waveguide and elliptical fiber at two temperatures, 20 C and 300 C. These temperatures were chosen to represent a nominal and a high temperature that the device would experience. Using the electric field profile calculated from each method, the theoretical coupling efficiency between the single-mode optical fiber and rib waveguide was calculated using the overlap integral and results of the techniques compared. Initially, perfect alignment was assumed and the coupling efficiency calculated. Then, the coupling efficiency calculation was repeated for a range of transverse offsets at both temperatures. Results of the calculation indicate a high coupling efficiency can be achieved when the two components were properly aligned. The coupling efficiency was more sensitive to alignment offsets in the y direction than the x, due to the elliptical modal profile of both components. Changes in the coupling efficiency over temperature were found to be minimal.

Tuma, Margaret L.↗

DOE OSTI2023

NucD-24 Nuclear Diagnostics Development: Time resolved 12 C-rhoR on GCD and NIS technology development for polar LOS and data quality [Slides]

The Neutron Imaging team is readying for the NIS2 polar LOS development and future improvements to data quality on all LOS given consistently higher yields at NIF. Next-gen nano guide scintillators for NIS2 and CMOS cameras to replace outdated CCDs will be studied. Digital image plates will be tested for better data quality on passive imaging systems. The transition into the ignition regime is expected to show a significant signature in the ablator areal density. In the marginal ignition regime, a decrease of 12C-rhoR (ablator areal density) is expected but once the burn propagation produces a shock and compresses the ablator the trend reverses. GCD with the PD-PMT can resolve this effect in the ablator areal density by a temporal shift in the carbon signal. To give quantitative results a calibration of the detector for the Hohlraum/TMP signal is needed. Shots using Al, Si, and Au pucks will yield the needed information to move forward with this project.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

NASA NTRS2000

Cell movement is guided by the rigidity of the substrate

Directional cell locomotion is critical in many physiological processes, including morphogenesis, the immune response, and wound healing. It is well known that in these processes cell movements can be guided by gradients of various chemical signals. In this study, we demonstrate that cell movement can also be guided by purely physical interactions at the cell-substrate interface. We cultured National Institutes of Health 3T3 fibroblasts on flexible polyacrylamide sheets coated with type I collagen. A transition in rigidity was introduced in the central region of the sheet by a discontinuity in the concentration of the bis-acrylamide cross-linker. Cells approaching the transition region from the soft side could easily migrate across the boundary, with a concurrent increase in spreading area and traction forces. In contrast, cells migrating from the stiff side turned around or retracted as they reached the boundary. We call this apparent preference for a stiff substrate "durotaxis." In addition to substrate rigidity, we discovered that cell movement could also be guided by manipulating the flexible substrate to produce mechanical strains in the front or rear of a polarized cell. We conclude that changes in tissue rigidity and strain could play an important controlling role in a number of normal and pathological processes involving cell locomotion.

NASA Discipline Cell Biology↗

NASA NTRS2016

Recovery of Large Angular Scale CMB Polarization for Instruments Employing Variable-Delay Polarization Modulators

Variable-delay Polarization Modulators (VPMs) are currently being implemented in experiments designed to measure the polarization of the cosmic microwave background on large angular scales because of their capability for providing rapid, front-end polarization modulation and control over systematic errors. Despite the advantages provided by the VPM, it is important to identify and mitigate any time-varying effects that leak into the synchronously modulated component of the signal. In this paper, the effect of emission from a 300 K VPM on the system performance is considered and addressed. Though instrument design can greatly reduce the influence of modulated VPM emission, some residual modulated signal is expected. VPM emission is treated in the presence of rotational misalignments and temperature variation. Simulations of time-ordered data are used to evaluate the effect of these residual errors on the power spectrum. The analysis and modeling in this paper guides experimentalists on the critical aspects of observations using VPMs as front-end modulators. By implementing the characterizations and controls as described, front-end VPM modulation can be very powerful for mitigating 1/ f noise in large angular scale polarimetric surveys. None of the systematic errors studied fundamentally limit the detection and characterization of B-modes on large scales for a tensor-to-scalar ratio of r= 0.01. Indeed, r less than 0.01 is achievable with commensurately improved characterizations and controls.

Miller, N. J.↗

DOE OSTI2024

Spin-Controllable Dynamics in Defect-Engineered Carbon Nanotubes as Single Photon Emitters: Data-Driven Modeling and Computations

Quantum technologies, such as quantum computing and sensing, require efficient single-photon emission (SPE) sources that operate at room temperature in telecom wavelengths. While several materials can serve as SPE sources, no single platform meets all the criteria for efficiency, ambient operation, and scalability. Single-walled carbon nanotubes (SWCNTs) with covalently attached molecules offer a promising solution. Their SPE can be easily tuned via modifications of the SWCNT's diameter, chirality, and bonded molecules, enabling emission across near-IR to telecom wavelengths at ambient conditions. However, to fully realize the potential of SWCNTs and unlock their quantum capabilities, a deeper understanding of how structural defects from molecular adducts affect their emission and competing photoexcited processes is essential. To address this gap in our knowledge, this project combined quantum chemistry calculations with data-driven methods of cheminformatics (QSAR) and machine learning (ML). The developed computational approaches have provided several design strategies for covalent functionalization of SWCNTs to improve their optical response. The collaboration with Los Alamos National Lab (LANL) enabled direct comparison of computational and experimental data, facilitating method validation. This partnership was enhanced through access to LANL's Center for Integrated Nanotechnologies (CINT) utilizing User Facility Program and summer internships, which provided three NDSU graduate students with hands-on experience at LANL. The outcomes of this project included (1) Advancing the current stage of computational methods in accurate modeling of non-adiabatic spin-dependent photoexcited dynamics and its applicability to nanosystems consisting of thousands of atoms, realized as open-access codes linked to existing DFT-based software; (2) Establishing the relationship between the structure of adducts and SWCNTs and intrinsic excitonic and spin properties of defect states for guiding novel synthetic strategies and experimental probes of chemically functionalized SWCNTs as near-IR emitting materials; (3) Generating virtual libraries of hypothetical functionalized SWCNTs for virtual screening of their chemical structures and optical properties, leveraging new functionalities of SWCNTs; (4) Offering a unique experience for NDSU graduate students that prepared them for future scientific careers related to materials modeling and big data processing. These results were summarized in 12 published journal papers and 3 recently submitted papers. One of a key finding is that the position of defect sites on the SWCNT surface primarily drives the emission redshift (up to 100 meV), while the polarity of the defect-inducing molecules has a much smaller effect (~10 meV). However, the electron-donating or withdrawing properties of a molecule influence selecting reactivity of defect sites. These insights important for optimizing synthetic protocols for desired emissions in SWCNTs. We also revealed that the interaction between two defects at various positions on the SWCNT enhances the redshift and optical activity of states, favoring strong near-IR emission. This suggests that manipulations in defect concentrations is a promising strategy for controlling efficient emission. Mostly important, the defect position was found controllable by the spin states of photoexcited intermediates: Excited aromatic molecules form ortho defects with SWCNTs at their singlet states in the presence of oxygen, while oxygen-free conditions favor para defects via the triplet-state mechanism. Additionally, a heat-activated [2+2] cycloaddition reaction facilitates divalent defect formation with fewer bonding positions that narrows emission bands. These groundbreaking findings have been experimentally validated and significantly advance our understanding of defect chemistry in SWCNTs. Using a novel encoding technique and 3D-MoRSE descriptors, we developed highly accurate ML/QSAR models to predict both the 3D structure and optical properties of SWCNTs with chemical defects. This model enabled the creation of a virtual library of 125,556 structures, providing new insights into the relationship between SWCNT-defect structure and emission.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

NASA NTRS1995

ASTRO-2 Spacelab Instrument Pointing System mission performance

This paper reports the performance of the Instrument Pointing System (IPS) that flew on the National Aeronautics and Space Administration (NASA) ASTRO-2 Spacelab mission aboard the Space Shuttle Endeavour in March 1995. The IPS provides a stabilizing platform for the ASTRO-2 instrument payload complement that consists of three main experiments (telescopes). The telescopes observe stellar targets in the universe within the ultraviolet portion of the electromagnetic spectrum that must be observed from beyond the earth's atmospheric filtering effects. The three main experiments for observation are the Hopkins Ultraviolet Telescope (HUT), the Ultraviolet Imaging Telescope (UIT), and the Wisconsin Ultraviolet Photo-Polarimetry Experiment (WUPPE). The HUT uses spectroscopy to obtain the structure and chemical makeup of ultraviolet targets. UIT is responsible for wide field photographing to capture the hidden view of the ultraviolet universe. The WUPPE gathers data on the polarization of the ultraviolet electromagnetic energy coming from the astronomical targets. The capability of IPS enables the experiments to 'see' faint celestial objects. A brief explanation of the IPS is given followed by a review of engineering efforts to improve IPS performance over the ASTRO-1 mission. The main focus of improvements was on enhancing the star acquisition capability through improved guide star selection, lab simulations, computer upgrades, data display systems improvements, and software modifications. A star simulator was developed in the lab to enable IPS to be simulated on the ground pre-mission with flight hardware and software in the loop. The paper concludes with results from the ASTRO-2 mission. The number of targets acquired and the IPS pointing accuracy/stability is reported along with recommendations for the future use of the Instrument Pointing System.

Wessling, Francis C., III↗

DOE OSTI2022

Monolayer Sc 2 CF 2 as a Potential Selective and Sensitive NO 2 Sensor: Insight from First-Principles Calculations

Two-dimensional materials with excellent surface–volume ratios and massive reaction sites recently have been receiving attention for gas sensing. With first-principles calculations, we explored the performance of monolayer Sc 2 CF 2 as a gas sensor. We investigated how molecule adsorption affects its electronic structure and optical properties. It is found that a large charge transfer quantity happens between Sc 2 CF 2 and NO 2 , which results from the fact that the lowest unoccupied molecular orbital (LUMO) of NO 2 is below the valence band maximum (VBM) of Sc 2 CF 2 . Moreover, the MD simulation shows that NO 2 can adsorb on the Sc 2 CF 2 surface stably at room temperature. We explored the effect of biaxial strain on the adsorption energy and charge transfer quantity of each system, and the results show that the biaxial strain can enhance both the adsorption energy and charge transfer quantity of the NO 2 system and thus can improve the sensitivity of Sc 2 CF 2 in detecting the NO 2 molecule. Furthermore, we investigated the adsorption behavior and charge transfer of polar polyatomic molecules at the Sc 2 CF 2 surface with h-BN as a substrate, and the results demonstrate that the h-BN substrate can hardly modify the main results. Our result predicts that Sc 2 CF 2 can be a promising selective and sensitive sensor to detect the NO 2 molecule, and could also give a theoretical guide for other terminated MXenes used for gas sensors or detectors.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Solubility-Dependent Protective Effects of Binary Alloys for Lithium Anode

Recently, alloys have been widely utilized as protection layers for homogenized Li growth. However, the protective mechanisms for different alloys are not clearly understood. In this work, guided by the binary phase diagrams, Mg, Au, Zn, Al, Fe, and Cu protective layers have been selected for study of their protective abilities and mechanisms. The selected metals can be classified into three categories according to the nature of their associated alloy protective layers: (1) metals with high solubility in Li while not forming any intermediate line compounds, e.g., Mg, which is good for fast Li stripping; (2) metals with limited solid solubility but forming stable line compounds with Li upon the lithiation, e.g., Au, Zn, and Al, where the formed stable line compounds Li x Au, Li x Zn, and Li x Al will hamper Li kinetics; (3) metals with negligible mutual solubility and no line compound formation with Li, e.g., Fe and Cu, which block the Li stripping path and therefore result in the highest polarization voltage.

25 ENERGY STORAGE↗

DOE OSTI2023

Polarity effects on wake–up behavior of Al 0.94 B 0.06 N ferroelectrics

Wurtzite ferroelectric materials are promising candidates for energy-efficient memory technologies, particularly for applications requiring high operating temperatures. Asymmetric wake-up behaviors, in which the polarization reversal depends both on polarity and cycle number for the first few dozen cycles, must be better understood for reliable device operation. Here, the detailed analysis of the asymmetric wake-up behavior of thin film Al 0.94 B 0.06 N was performed combining time-resolved switching measurements with Rayleigh analysis, piezoelectric measurements, and etching experiments of progressively switched samples. Furthermore, the analysis shows that the gradual opening of the polarization hysteresis loops associated with wake-up is driven by a gradual increase in the domain-wall density and/or domain-wall mobility with electric field cycle to the polarity opposite to the growth polarity. The insights of this discovery will help to guide interface and polarity design in the eventual deployment of reliable devices based on these materials.

36 MATERIALS SCIENCE↗

DOE OSTI2026

EvoDiffMol: evolutionary diffusion framework for 3D molecular design with optimized properties

Designing molecules with specific target properties remains a fundamental challenge in computational chemistry. While existing approaches show promise, most rely on simplified representations like SMILES strings or 2D graphs that lack essential three-dimensional geometric information. We present EvoDiffMol, a computational framework that integrates evolutionary algorithms with three-dimensional diffusion models for property-driven molecular generation. The method operates through adaptive evolutionary optimization, where population-based selection guides the generation process toward desired property landscapes. EvoDiffMol supports both unconstrained molecular design and scaffold-constrained generation that preserves fixed substructures while optimizing complementary regions. Comprehensive evaluation demonstrates exceptional performance, achieving the highest drug-likeness score (0.94) among all compared state-of-the-art methods while maintaining excellent validity, uniqueness, and novelty. Beyond single property optimization, the framework demonstrates flexible multi-property optimization capabilities, simultaneously controlling multiple molecular descriptors including synthetic accessibility, lipophilicity, topological polar surface area, and clinically relevant ADMET properties such as cardiotoxicity (hERG) and intestinal permeability (Caco-2). This adaptability spans from simple descriptors to practical pharmaceutical endpoints without requiring complete model retraining. The framework achieves precise control over target property values, generating molecules with properties closely matching specified targets for both single and multiple descriptors. Scaffold-constrained experiments preserve fixed molecular cores while maintaining effective property optimization. The three-dimensional representation offers advantages in maintaining structural validity during iterative optimization, with potential for geometry-aware applications in materials science and drug discovery.

3D molecular generation↗

NASA NTRS1992

Inferences concerning the magnetospheric source region for auroral breakup

Inferences concerning the magnetospheric source region for auroral arcs obtained from particle measurements on polar orbiting satellites are presented and contrasted with other ideas. An argument that the magnetospheric source region for auroral arc breakup and substorm initiation is along Boundary Plasma Sheet (BPS) magnetic field lines is given. This source region lies beyond a distinct central plasma sheet region and sufficiently far from the Earth that energetic ion motion violates the guiding center approximation (is chaotic). The source region is not constrained to any particular range of distances from the Earth, and substorm initiation may be possible over a wide range of distances from near synchronous orbit to the distant tail. It is also argued that the layer of low energy electrons and velocity dispersed ion beams observed at low altitudes on Aureol 3 is not a different region from the region of auroral arcs. Both comprise the BPS. The two regions occasionally appear distinct at low altitudes because of the effects of arc field aligned potential drops on precipitating particles.

Lyons, L. R.↗

DOE OSTI2020

BeyondPlanck I. Global Bayesian analysis of the Planck Low Frequency Instrument data

We describe the BeyondPlanck project in terms of motivation, methodology and main products, and provide a guide to a set of companion papers that describe each result in fuller detail. Building directly on experience from ESA's Planck mission, we implement a complete end-to-end Bayesian analysis framework for the Planck Low Frequency Instrument (LFI) observations. The primary product is a joint posterior distribution P(omega|d), where omega represents the set of all free instrumental (gain, correlated noise, bandpass etc.), astrophysical (synchrotron, free-free, thermal dust emission etc.), and cosmological (CMB map, power spectrum etc.) parameters. Some notable advantages of this approach are seamless end-to-end propagation of uncertainties; accurate modeling of both astrophysical and instrumental effects in the most natural basis for each uncertain quantity; optimized computational costs with little or no need for intermediate human interaction between various analysis steps; and a complete overview of the entire analysis process within one single framework. As a practical demonstration of this framework, we focus in particular on low-l CMB polarization reconstruction, paying special attention to the LFI 44 GHz channel. We find evidence of significant residual systematic effects that are still not accounted for in the current processing, but must be addressed in future work. These include a break-down of the 1/f correlated noise model at 30 and 44 GHz, and scan-aligned stripes in the Southern Galactic hemisphere at 44 GHz. On the Northern hemisphere, however, we find that all results are consistent with the LCDM model, and we constrain the reionization optical depth to tau = 0.067 +/- 0.016, with a low-resolution chi-squared probability-to-exceed of 16%. The marginal CMB dipole amplitude is 3359.5 +/- 1.9 uK. (Abridged.)

Andersen, KJ↗

DOE OSTI2024

Physics-informed machine learning to predict solvatochromic parameters of designer solvents with case studies in CO 2 and lignin dissolution

The polarity of solvents plays a critical role in various research applications, particularly in their solubilities. Polarity is conveniently characterized by the Kamlet-Taft parameters that is, the hydrogen bonding acidity (α), the basicity (β), and the polarizability (π*). Obtaining Kamlet-Taft parameters is very important for designer solvents, namely ionic liquids (ILs) and deep eutectic solvents (DESs). However, given the unlimited theoretical number of combinations of ionic pairs in ILs and hydrogen-bond donor/acceptor pairs in DESs, experimental determination of their Kamlet-Taft parameters is impractical. To address this, the present study developed two different machine learning (ML) algorithms to predict Kamlet-Taft parameters for designer solvents using quantum chemically derived input features. The ML models developed in the present study showed accurate predictions with high R 2 and low RMSE values. Further, in the context of present interest in the circular bioeconomy, the relationship between the basicities and acidities of designer solvents and their ability to dissolve lignin and carbon dioxide (CO 2 ) is discussed. Our method thus guides the design of effective solvents with optimal Kamlet-Taft parameter values dissolving and converting biomass and CO 2 into valuable chemicals.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗