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DOE OSTI2016

Seven 3d-4f coordination polymers of macrocyclic oxamide with polycarboxylates: Syntheses, crystal structures and magnetic properties

Seven new 3d–4f heterometallic coordination polymers, [Ln(CuL){sub 2}(Hbtca)(btca)(H{sub 2}O)]·2H{sub 2}O (Ln = Tb{sup III}1, Pr{sup III}2, Sm{sup III}3, Eu{sup III}4, Yb{sup III}5), [Nd(NiL)(nip)(Rnip)]·0·25H{sub 2}O·0.25CH{sub 3}OH (R= 0.6CH{sub 3}, 0.4H) 6 and [Nd{sub 2}(NiL)(nip){sub 3}(H{sub 2}O)]·2H{sub 2}O 7(CuL or NiL, H{sub 2}L = 2, 3-dioxo-5, 6, 14, 15-dibenzo-1, 4, 8, 12-tetraazacyclo-pentadeca-7, 13-dien; H{sub 2}btca = benzotriazole-5-carboxylic acid; H{sub 2}nip = 5-nitroisophthalic acid) have been synthesized by a solvothermal method and characterized by single-crystal X-ray diffraction. Complexes 1–5 exhibit a double-strand meso-helical chain structures formed by [Ln{sup III}Cu{sup II}{sub 2}] units via the oxamide and benzotriazole-5-carboxylate bridges, while complex 6 exhibits a four-strand meso-helical chain formed by NdNi unit via the oxamide and 5-nitroisophthalate bridges. Complex 7 consists of a 2D layer framework formed by four-strand meso-helical chain via the nip{sup 2−} bridges. Moreover, the magnetic properties of them were investigated, and the best-fit analysis of χ{sub M}T versus T show that the anisotropic contribution of Ln(III) ions (arising from the spin-orbit coupling or the crystal field perturbation) dominates (weak exchange limit) in these complexes(for 3, λ = 214.6 cm{sup −1}, zj’ = −0.33 cm{sup −1}, g{sub av} = 1.94; for 5, Δ = 6.98 cm{sup −1}, zj’ = 1.53 cm{sup −1}, g{sub av} = 1.85). - Graphical-abstract: Seven novel oxamido-bridged 3d-4f heterometallic coordination polymers with benzotriazole-5-carboxylate or 5-nitroisophthalate co-ligands under solvothermal reaction conditions. Polymers 1–7 hold 1D or 2D framework structure, viz., double-strand meso-helical chain of 1–5, four-strand meso-helical chain of 6, and 2D net of 7 consisting of four-strand meso-helical chain. Moreover, the temperature dependences of magnetic susceptibilities of compounds 1–7 were also studied.

36 MATERIALS SCIENCE↗

DOE OSTI2026

A Visual Understanding of Circular Dichroism Spectroscopy

Mapping chemical and structural properties to electronic and magnetic responses is critical to many applications such as quantum information science, where the precise storage and transmission of unique information is paramount. Specifically, constructing molecules and materials that provide strong polarized responses at tunable frequencies and with large anisotropies is key to optical processing of quantum information. Chiral molecules provide chiroptical response to circularly polarized light, making them attractive for quantum information science and other applications related to sensing, polarized photodetectors, and spintronics. Predicting a molecular design, a priori, with large anisotropies to circularly polarized light is challenging due to the complex interplay between electric and magnetic components of the optical response. In this work, we explore a visual representation of the electronic chiroptical response by decomposing the rotary strength into its constituent components. Here, we make use of the intuitive electronic oscillator framework to develop classical intuition regarding the rotary strength and its constituents. We explore three model chemical systems that exhibit local and global chirality. Our analysis reveals that local chirality necessarily exhibits competition between the local chiral center and chirality induced in other fragments of the molecule, resulting in both unexpected nonmonotonic trends and sign flips in chemically adjacent geometries. Furthermore, we can visually distinguish between local and global chirality via examination of the transition chiral tensor. Interestingly, we make strong connections to ferromagnetic and antiferromagnetic spin systems in that chiroptically inactive transitions exhibit antiferromagnetic-like alternating orbital patterns while active transitions show domain formation in an ferromagnetic-like alignment that produces a net chiroptical response.

36 MATERIALS SCIENCE↗

DOE OSTI2013

3D Rare earth porous coordination frameworks with formamide generated in situ syntheses: Crystal structure and down- and up-conversion luminescence

The reaction of RE(NO)₃·6H₂O and formamide yielded the coordination polymers, [RE(HCOO)₄]⁻[NH₂CHNH₂]⁺ (RE=Y 1, Eu 2, Gd 3, Tb 4, Dy 5, Er 6, and Yb 7). They possess 3D porous frameworks with the 1D rhombic channels occupied by [NH₂CHNH₂]⁺ cations. Complexes 2 and 4 display the characteristic down-conversion emissions corresponding to ⁵D₀→⁷F J (J=1–4) transitions of Eu(III) ion and ⁵D₄→⁷F J (J=6–3) transitions of Tb(III) ion, respectively. Longer lifetime values of 2.128±0.002 ms (⁵D₀) for 2 and 2.132±0.002 ms (⁵D₄) for 4 have been observed. The up-conversion spectra of the Y:Yb,Er and Gd:Yb,Er codoped complexes exhibit three emission bands around 410 (⁴H 9/2 →⁴I 15/2 , blue), 518–570 (⁴S 3/2 , ²H 11/2 →⁴I 15/2 , green), and 655 nm (⁴F 9/2 →⁴I 15/2 , red). - Graphical Abstract: The complexes [RE(HCOO)₄]⁻[NH₂CHNH₂]⁺ possess 3D porous frameworks. Eu(III) and Tb(III) complexes show characteristic emission of Ln(III) ions. The up-conversion emission of the Y:Yb,Er and Gd:Yb,Er codoped complexes was observed. Highlights: •The reaction of RE(NO)₃·6H₂O and formamide produced complexes [RE(HCOO)₄]⁻[NH₂CHNH₂]⁺. • The complexes possess 3D frameworks with the 1D channels occupied by [NH₂CHNH₂] + cations. • Eu(III)/Tb(III) complexes display the characteristic down-conversion emission of Ln(III) ions. • The Y:Yb,Er and Gd:Yb,Er doped complexes exhibit the up-conversion emission.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

Controlled Demolition and Reconstruction of Imidazolate and Carboxylate Metal–Organic Frameworks by Acid Gas Exposure and Linker Treatment

The metal-linker coordination bond in metal–organic frameworks (MOFs) can be unstable in humid and acid gas environments, leading to loss of crystallinity and porosity. This degradation is not necessarily irreversible; solvent-assisted crystal redemption (“SACRed”) has been shown to recover the physical and chemical properties of ZIF-8 exposed to humid SO 2 . This approach can also be useful in creating mixed-linker materials that might be challenging to produce via de novo synthesis. Here, we expand more generally the concept of controlled degradation of a MOF with acid gas, followed by treatment with a fresh linker solution, to the use of different template MOFs (ZIFs, UiO-66, and UiO-67) and acid gases (SO 2 and NO 2 in dry and humid conditions). Significant losses in porosity and crystallinity along with structural changes (acid gas-linker complexes and linker functionalizations) are observed in the acid gas-exposed MOF templates, and SACRed is shown to reconstruct these partially demolished MOFs with a high degree of structural recovery. Detailed structural and spectroscopic characterizations of the controlled degradation and subsequent recovery are presented and analyzed. Furthermore, these findings indicate the generality of controlled degradation and reconstruction as a means for linker replacement in a wider variety of MOFs and also create the potential for linker substitutions (with non-native linkers) to obtain new hybrid MOFs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2023

Modeling diffusion and types I-V sorption of water vapor in heterogeneous systems

Here, a sorption and diffusion model is developed using a mobile-immobile decomposition of the vapor concentration. Henry’s mode represents the mobile species which diffuses through the solid, while Langmuir and pooling modes represent possible immobilization processes that cause nonlinearities in sorption capacity. The model can simulate the five classical sorption types and can incorporate additional dynamics compared to models based on thermodynamic equilibrium. Additionally, the framework allows for discontinuities in material properties encountered in multi-material systems. The resulting non-linear coupled equations are solved by employing a finite element method to discretize in space, and a backward Euler method to discretize in time. The discretized system of equations is solved via a Newton-type iteration scheme at each time-step. Four different materials are parameterized for the model, which are then used in examples to demonstrate the model’s ability to capture complex sorption processes in multi-material systems.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2024

On a High-Mirror Stellarator Reactor Exploratory Concept With Neutrons Concentrated on Centrifuge Liquids

In the framework of fusion energy research based on magnetic confinement, stellarators allow numerous degrees of freedom for the design of the magnetic trap and plasma shape. Taking advantage of these features, some plasma shapes might benefit several of the many integrated elements involved in commercial fusion reactors, like, e.g., decreasing the number, mass and complexity of replaced activated in-vessel components (IVC) (i.e., by using liquids), extraction of large power, tritium generation, and remote maintenance. Certainly, free-surface liquid materials were proposed for tokamaks and field-reversed configuration (FRC) to try to improve some of such elements, i.e., in advanced power extraction (APEX) studies. Some reactor-relevant quasi-isodynamic (QI) magnetic configurations exhibit a relatively straight sector of plasma and high magnetic mirror. The combination of those elements and possibilities in a single stellarator reactor concept might have some advantages, in spite of the uncertainties due to the current low technological readiness level (TRL). The proposed and studied reactor concept is based on a vacuum vessel having short curved sectors and longer wide cylindrical sectors, which encloses a high-mirror low-vertical-excursion magnetic configuration, and swirling liquids or rotating cylinders, which centrifuge molten Li salts located at the low field region. Thus, the molten salts (if possible covered by a thin layer of liquid lithium) would be located on the internal perimeter of the cylinder, to act as particle exhaust (except for helium), neutron power extractor, and tritium breeder. The high-mirror feature tries to concentrate the neutron power at the cylindrical sectors, which might avoid using breeding materials at the curved sectors. The different elements of the concept are exploratorily studied and defined, and the difficulties assessed.

centrifuge↗

DOE OSTI2017

Initial 1.5D BISON Simulation Verification and Validation CASL FY17 Letter Report

This milestone report describes the current efforts to improve the usability of the recently developed 1.5 dimensional capability in BISON, the initial verification of this BISON capability, and initial validation of the 1.5 dimensional models against existing 2 dimensional axisymmetric full length light water reactor (LWR) fuel rods. The 1.5 dimensional (1.5D) capability in BISON was developed to enable the simulation of LWR fuel rods in a less computationally demanding simulation formulation while retaining key physics of interest. BISON was originally developed to solve 2D axisymmetric and 3D models, and this original development focus allows BISON to examine a wider range of fuel types and geometrically complexity than can be solved with lower dimensional frameworks. As the set of problems which BISON is used to solve expands, the software design requirements continue to evolve. Coupling physics in a higher dimensional geometry is not always required to resolve the physics of interest, such as the modeling of radial heat transfer and radial displacement. BISON, built on the dimension-agnostic MOOSE framework, is able to solve problems in 3D, 2D, and 1D with only minor modifications to the material definition code so that the appropriate geometrical representation can be applied in different problems of interest. The motivation for the development and validation of the BISON 1.5D capability is the CASL program's need for a simplified and computationally efficient version of BISON for use in the large multi-physics VERA simulations which include hundreds of individual fuel rods. The original development of the BISON 1.5D simulation capability is described in the CASL FY17 Letter Report from January 2017, and this report documents the continuing work identified in the previous report. The improvements to the usability of the 1.5D capability through input file simplifications, the results of the verification simulations, the results of the initial validation against the 2D assessment cases in BISON, and the future development needs are included within this report.

1.5D Capability↗

NASA NTRS2016

Probabilistic Modeling Of Ocular Biomechanics In VIIP: Risk Stratification

Visual Impairment and Intracranial Pressure (VIIP) syndrome is a major health concern for long-duration space missions. Currently, it is thought that a cephalad fluid shift in microgravity causes elevated intracranial pressure (ICP) that is transmitted along the optic nerve sheath (ONS). We hypothesize that this in turn leads to alteration and remodeling of connective tissue in the posterior eye which impacts vision. Finite element (FE) analysis is a powerful tool for examining the effects of mechanical loads in complex geometries. Our goal is to build a FE analysis framework to understand the response of the lamina cribrosa and optic nerve head to elevations in ICP in VIIP. To simulate the effects of different pressures on tissues in the posterior eye, we developed a geometric model of the posterior eye and optic nerve sheath and used a Latin hypercubepartial rank correlation coef-ficient (LHSPRCC) approach to assess the influence of uncertainty in our input parameters (i.e. pressures and material properties) on the peak strains within the retina, lamina cribrosa and optic nerve. The LHSPRCC approach was repeated for three relevant ICP ranges, corresponding to upright and supine posture on earth, and microgravity [1]. At each ICP condition we used intraocular pressure (IOP) and mean arterial pressure (MAP) measurements of in-flight astronauts provided by Lifetime Surveillance of Astronaut Health Program, NASA Johnson Space Center. The lamina cribrosa, optic nerve, retinal vessel and retina were modeled as linear-elastic materials, while other tissues were modeled as a Mooney-Rivlin solid (representing ground substance, stiffness parameter c1) with embedded collagen fibers (stiffness parameters c3, c4 and c5). Geometry creationmesh generation was done in Gmsh [2], while FEBio was used for all FE simulations [3]. The LHSPRCC approach resulted in correlation coefficients in the range of 1. To assess the relative influence of the uncertainty in an input parameter on the peak strains, we ranked and then normalized these coefficients, considering that normalized values 0.5 implied a substantial influence on the range of the peak strains in the optic nerve head (ONH). IOP and ICP were found to have a major influence on the peak strains in the ONH, as did optic nerve and LC stiffness. Interestingly, the stiffness of the sclera far from the scleral canal did not have a large influence on peak strains in ONH tissues; however, the collagen fiber stiffness in the peripapillary sclera and annular ring both influenced the peak strains within the ONH. We have created a physiologically relevant model that incorporated collagen fibers to study the effects of elevated ICP. Elevated ICP resulted in strains in the optic nerve that are not predicted to occur on earth: the upright or supine conditions. We found that IOP, ICP, lamina cribrosa stiffness and optic nerve stiffness had the highest association with these extreme strains in the ONH. These extreme strains may activate mechanosensitive cells that induce tissue remodeling and are a risk factor for the development of VIIP.

biomechanics↗

DOE OSTI2015

Novel Metal-Organic Frameworks for Efficient Stationary Sources via Oxyfuel Combustion

Oxy-fuel combustion is a well-known approach to improve the heat transfer associated with stationary energy processes. Its overall penetration into industrial and power markets is constrained by the high cost of existing air separation technologies for generating oxygen. Cryogenic air separation is the most widely used technology for generating oxygen but is complex and expensive. Pressure swing adsorption is a competing technology that uses activated carbon, zeolites and polymer membranes for gas separations. However, it is expensive and limited to moderate purity O 2 . MOFs are cutting edge materials for gas separations at ambient pressure and room temperature, potentially revolutionizing the PSA process and providing dramatic process efficiency improvements through oxy-fuel combustion. This LDRD combined (1) MOF synthesis, (2) gas sorption testing, (3) MD simulations and crystallography of gas siting in pores for structure-property relationship, (4) combustion testing and (5) technoeconomic analysis to aid in real-world implementation.

02 PETROLEUM↗

DOE OSTI2018

Oxidation Protection with Amorphous Surface Oxides: Thermodynamic Insights from Ab Initio Simulations on Aluminum

Native surface films play a key role in the oxidation and corrosion protection of functional and structural materials. In this work, we introduce a fully ab initio approach for understanding the thermodynamic driving force behind the initial phase selection among amorphous and crystalline structures for a surface film growing on a crystalline substrate. We apply the approach to elucidate the competition among corundum (α), spinel (γ), and amorphous (am.) Al 2 O 3 films growing on aluminum metal. We show that the amorphous Al 2 O 3 film becomes thermodynamically the most stable form below around ~1 nm, that is, the relative energetic stabilities of thin polymorphic Al 2 O films follow am. < γ < α. As the film thickness increases, the relative stability relation first changes to γ < α < am. and then to the bulk limit of α < γ < am. The nanoscale γ films distort substantially to form exclusively four- and fivefold-coordinated Al–O polyhedra, lose the close-packed O framework, and become “amorphous-like”, that is, exhibit both short-range order and energetic characteristics that are commensurate with the amorphous form. Our findings offer a quantitative, first-principles confirmation for the early hypotheses on the thermodynamic stability of amorphous surface films and provide insights for the critical role they play in oxidation protection. Handling the complexities associated with the initial film growth, including bulk, surface, interface, and strain energy effects in realistically complex ab initio simulations, we expect this approach to contribute to understanding of the mechanism behind effective passivation films for aluminum alloys and beyond.

36 MATERIALS SCIENCE↗

DOE OSTI2024

Turning Normal to Abnormal: Reversing CO 2 /C2–Hydrocarbon Selectivity in HKUST–1

Metal–organic frameworks (MOFs) can efficiently purify hydrocarbons from CO 2 , but their rapid saturation, driven by preferential hydrocarbon adsorption, requires energy-intensive adsorption–desorption processes. To address these challenges, an innovative approach is developed, enabling control over MOF flexibility through densification and defect engineering, resulting in an intriguing inverse CO 2 /C2 hydrocarbon selectivity. Here, in this study, the densification process induces the shearing of the crystal lattice and contraction of pores in a defective CuBTC MOF. These changes have led to a remarkable transformation in selectivity, where the originally hydrocarbon-selective CuBTC MOF becomes CO 2 -selective. The selectivity values for densified CuBTC are significantly reversed when compared to its powder form, with notable improvements observed in CO 2 /C 2 H 6 (4416 vs 0.61), CO 2 /C 2 H 4 (15 vs 0.28), and CO 2 /C 2 H 2 (4 vs 0.2). The densified material shows impressive separation, regeneration, and recyclability during dynamic breakthrough experiments with complex quinary gas mixtures. Simulation studies indicate faster CO 2 passage through the tetragonal structure of densified CuBTC compared to C 2 H 2 . Experimental kinetic diffusion studies confirm accelerated CO 2 diffusion over hydrocarbons in the densified MOF, attributed to its small pore window and minimal interparticle voids. This research introduces a promising strategy for refining existing and future MOF materials, enhancing their separation performance.

36 MATERIALS SCIENCE↗

DOE OSTI2024

Optimizing high energy density sulfur cathodes: A multivariate approach to electrode formulation and processing

Lithium-sulfur (Li-S) batteries involve complex solid-liquid-solid phase transformations during both discharging and charging processes, where cathode materials, formulation, and structure play a crucial role. Here, a design of experiments (DoE) methodology and an empirical model are developed to systematically explore the interactions and trade-offs among cathode factors and process variables, and to obtain generalizable effects estimates for the multivariate system. Compared to the conventional one-factor-at-a-time (OFAT) approach, this work demonstrates advantages in both efficiency and accuracy by allowing the data to guide future research and decisions. Further, an optimized cathode formulation and processing parameters are predicted and validated experimentally, achieving over 1000 mAh g -1 in discharge capacity and improved cycling under practical lean electrolyte (4 µL mg -1 S) and high S-loading cathodes (>4 mg cm -2 ) conditions. The optimized cathode was scaled up and assembled into Li-S pouch cells, achieving 316 Wh kg -1 in cell-level energy, proving that the comprehensive and rigorous framework for optimizing complex systems with DoE leads to improved performance in a practical pouch cell system.

25 ENERGY STORAGE↗

DOE OSTI2016

Identifying Optimal Zeolitic Sorbents for Sweetening of Highly Sour Natural Gas

Abstract Raw natural gas is a complex mixture comprising methane, ethane, other hydrocarbons, hydrogen sulfide, carbon dioxide, nitrogen, and water. For sour gas fields, selective and energy‐efficient removal of H 2 S is one of the crucial challenges facing the natural‐gas industry. Separation using nanoporous materials, such as zeolites, can be an alternative to energy‐intensive amine‐based absorption processes. Herein, the adsorption of binary H 2 S/CH 4 and H 2 S/C 2 H 6 mixtures in the all‐silica forms of 386 zeolitic frameworks is investigated using Monte Carlo simulations. Adsorption of a five‐component mixture is utilized to evaluate the performance of the 16 most promising materials under close‐to‐real conditions. It is found that depending on the fractions of CH 4 , C 2 H 6 , and CO 2 , different sorbents allow for optimal H 2 S removal and hydrocarbon recovery.

Shah, Mansi S.↗

DOE OSTI2016

Identifying Optimal Zeolitic Sorbents for Sweetening of Highly Sour Natural Gas

Shah, Mansi S.↗

DOE OSTI2017

Absolute Molecular Orientation of Isopropanol at Ceria (100) Surfaces: Insight into Catalytic Selectivity from the Interfacial Structure

The initial mechanistic steps underlying heterogeneous chemical catalysis can be described in a framework where the composition, structure, and orientation of molecules adsorbed to reactive interfaces are known. However, extracting this vital information is the limiting step in most cases due in part to challenges in probing the interfacial monolayer with enough chemical specificity to characterize the surface molecular constituents. These challenges are exacerbated at complex or spatially heterogeneous interfaces where competing processes and a distribution of local environments can uniquely drive chemistry. To address these limitations, this work presents a distinctive combination of materials synthesis, surface specific optical experiments, and theory to probe and understand molecular structure at catalytic interfaces. Specifically, isopropanol was adsorbed to surfaces of the model CeO 2 catalyst that were synthesized with only the (100) facet exposed. Vibrational sum-frequency generation was used to probe the molecular monolayer, and with the guidance of density functional theory calculations, was used to extract the structure and absolute molecular orientation of isopropanol at the CeO 2 (100) surface. Our results show that isopropanol is readily deprotonated at the surface, and through the measured absolute molecular orientation of isopropanol, we obtain new insight into the selectivity of the (100) surface to form propylene. Our findings reveal key insight into the chemical and physical phenomena taking place at pristine interfaces thereby pointing to intuitive structural arguments to describe catalytic selectivity in more complex systems.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2017

Final Scientific/Technical Report

A variety of calcifying organisms produce a transient or metastable amorphous calcium carbonate (ACC) precursor phase that is assembled and subsequently transformed into a crystalline biomineral, typically calcite or aragonite. The complex shapes, hierarchical structures, and unique physical properties of the biominerals that result from this calcification pathway have stimulated interest in adapting these concepts for the design and creation of bio-inspired functional materials in the laboratory. ACC also forms as a reactive precursor in diverse inorganic systems and is likely to play a much broader role in calcium carbonate formation. Knowledge of the structure, composition, and behavior of this metastable phase is critical for establishing a structural and mechanistic framework for calcium carbonate formation and its role in biogeochemical processes, including carbon cycling. Minor additives, such as magnesium, phosphorus, and organic macromolecules, are known to play important roles in controlling ACC stability, transformation kinetics, and selection of final crystalline polymorph. Molecular water also occurs in many types of ACC and is thought to play a structural role in its stability and transformation behavior. One of the major challenges that remain unresolved is identification of the structural basis for the role of these minor additives and molecular water. The absence of long-range order in ACC, and other amorphous phases, has posed a challenge for study by techniques commonly used for crystalline solids. Preliminary studies in our group show that the combination of two techniques, synchrotron X-ray-based pair distribution function (PDF) analysis and nuclear magnetic resonance (NMR) spectroscopy can provide entirely new insight to structural properties of synthetic ACC over length scales that are most relevant for understanding its transformation properties. Building on preliminary experiments, we propose a systematic study of synthesis, structure, and transformation behavior in abiotic systems. The work will specifically address the influence of phosphate as a minor additive. PDF analysis will utilize total X-ray scattering data collected at synchrotron facilities optimized for this method and will provide direct characterization of the short- and intermediate-range structure of ACC synthesized under controlled conditions. Parallel computational work using reverse Monte Carlo methods will allow structural models to be constructed for a more complete analysis of PDF results. NMR spectroscopy, using a variety of single- and double-resonance techniques, will provide information on H and CO3 components, including dynamical properties, and their relationship to stabilizing additives. PDF and NMR results will be complemented by parallel studies using X-ray absorption and FT-IR spectroscopy to allow direct comparison to previous studies. These techniques will be used to follow the transformation of different ACC samples, with specific additives, to crystalline phases under controlled condition (e.g., relative humidity). This work will provide the structural and mechanistic basis for understanding ACC stability, its transformation behavior, and the factors that govern polymorph selection. This new insight will directly benefit researchers in diverse fields, as well as adding to the framework of knowledge for understanding and controlling calcium carbonate formation in natural and engineered systems.

58 GEOSCIENCES↗

NASA NTRS2003

Earth's earliest biosphere-a proposal to develop a collection of curated archean geologic reference materials

The discovery of evidence indicative of life in a Martian meteorite has led to an increase in interest in astrobiology. As a result of this discovery, and the ensuing controversy, it has become apparent that our knowledge of the early development of life on Earth is limited. Archean stratigraphic successions containing evidence of Earth's early biosphere are well preserved in the Pilbara Craton of Western Australia. The craton includes part of a protocontinent consisting of granitoid complexes that were emplaced into, and overlain by, a 3.51-2.94 Ga volcanigenic carapace - the Pilbara Supergroup. The craton is overlain by younger supracrustal basins that form a time series recording Earth history from approximately 2.8 Ga to approximately 1.9 Ga. It is proposed that a well-documented suite of these ancient rocks be collected as reference material for Archean and astrobiological research. All samples would be collected in a well-defined geological context in order to build a framework to test models for the early evolution of life on Earth and to develop protocols for the search for life on other planets.

Archaea↗

DOE OSTI2024

Utilizing HYSPLIT for Emergency Response Modeling at SRS

At SRS, emergency responders use a variety of tools to detect, track, and mitigate hazardous material releases into the atmosphere. Two models currently used at SRS are Puff-Plume and the Lagrangian Particle Dispersion Model (LPDM), a Gaussian and Lagrangian model, respectively. A decision has been made to replace LPDM with the more widely-supported Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model for evaluating inhalation and ingestion doses following a release. HYSPLIT is designed to compute complex dispersion and deposition simulation To achieve the implementation of HYSPLIT, we have developed a preliminary UI framework that will allow HYSPLIT to be run on ATG computers without the need for active network connections, thus avoiding the loss of capabilities in the event of a network outage during an emergency.

Earley, Ian↗