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DOE OSTI2024

A discretized representation for Monte Carlo simulation of deformed semiflexible chains

In this study, we present a novel orientation discretization approach based on the rhombic triacontahedron for Monte Carlo simulations of semiflexible polymer chains, aiming at enhancing structural analysis through rheo-small-angle scattering (rheo-SAS). Our approach provides a more accurate representation of the geometric features of semiflexible chains under deformation, surpassing the capabilities of traditional lattice structures. Validation against the Kratky–Porod chain system demonstrated superior consistency, underscoring its potential to significantly improve the precision of uncovering geometric details from rheo-SAS data. Further, this approach opens new avenues for investigating the conformations of semiflexible polymers and mechanically induced phase transitions in more complex polymer structures, offering deeper insights into their behavior under various conditions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2025

Exact statistics of helical wormlike chains with twist-bend coupling

Here, we present a solution for the Green's function for the general case of a helical wormlike chain with twist-bend coupling and demonstrate the applicability of our solution for evaluating general structural and mechanical chain properties. We find that twist-bend coupling renormalizes the persistence length and the force-extension curves relative to wormlike chains. Analysis of intrinsically twisted polymers shows that incorporation of twist-bend coupling results in the oscillatory behavior in principal tangent correlations that are observed in some studies of synthetic polymers. The exact nature of our solution provides a framework to evaluate the role of twist-bend coupling on polymer properties, such as DNA bound to histones and motivates the reinterpretation of existing biopolymer experimental data.

Ghosh, Ashesh [University of California, Berkeley,↗

DOE OSTI2025

Magnetic properties of a staggered S = 1 chain with an alternating single-ion anisotropy direction

Materials composed of spin-1 antiferromagnetic (AFM) chains are known to adopt complex ground states that are sensitive to the single-ion-anisotropy (SIA) energy ( D ), and intrachain ( J 0 ) and interchain ( J 1 , 2 ′ ) exchange energy scales. While theoretical and experimental studies have extended this model to include various other energy scales, the effect of the lack of a common SIA axis is not well explored. Here we investigate the magnetic properties of Ni ( pyrimidine ) ( H 2 O ) 2 ( NO 3 ) 2 , a chain compound where the tilting of Ni octahedra leads to a twofold alternation of the easy-axis directions along the chain. Muon-spin relaxation measurements indicate a transition to long-range order at T N = 2.3 K and the magnetic structure is initially determined to be antiferromagnetic and collinear using elastic neutron diffraction experiments. Inelastic neutron scattering measurements were used to find J 0 = 5.107 ( 7 ) K , D = 2.79 ( 1 ) K , J 1 ′ = 0.00 ( 5 ) K , J 2 ′ = 0.18 ( 3 ) K , and a rhombic anisotropy energy E = 0.19 ( 9 ) K . Mean-field modeling reveals that the ground state structure hosts spin canting of ϕ ≈ 6 . 5 ∘ , which is not detectable above the noise floor of the elastic neutron diffraction data. Monte Carlo simulation of the powder-averaged magnetization, M ( H ) , is then used to confirm these Hamiltonian parameters, while single-crystal M ( H ) simulations provide insight into features observed in the data. Published by the American Physical Society 2025

Vaidya, S. (ORCID:000000033975497X)↗

DOE OSTI2024

Properties of the 256 Db decay chain

Experiments were performed at Lawrence Berkeley National Laboratory's 88-Inch Cyclotron Facility to study the decays of neutron-deficient dubnium isotopes. These isotopes were produced in the 206 Pb( 51 V, xn) 255,256 Db reaction, and excitation functions were measured. This article reports on the observed properties of the 256 Db decay chain. The produced 256 Db nuclei were separated from unreacted-beam material and reaction byproducts with the Berkeley Gas-filled Separator (BGS) before being implanted into a double-sided silicon strip detector at the BGS focal plane. Decay properties of 256 Db and its daughters were then extracted from the analysis of correlations between implanted Db nuclei with α decay chains and spontaneous fission (SF) events. In total, 86 decay chains and 38 SF events were observed, giving increased statistics as compared to previous studies. In conclusion, improved decay data are presented for 256 Db and its daughter isotopes 252 Lr, 252 No, 248 Md, 248 Fm, 244 Es, and 244 Cf.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2024

Enhancing quantum utility: Simulating large-scale quantum spin chains on superconducting quantum computers

We present the quantum simulation of the frustrated quantum spin- 1 2 antiferromagnetic Heisenberg spin chain with competing nearest-neighbor ( J 1 ) and next-nearest-neighbor ( J 2 ) exchange interactions in the real superconducting quantum computer with qubits ranging up to 100. In particular, we implement the Hamiltonian with the next-nearest neighbor exchange interaction in conjunction with the nearest-neighbor interaction on IBM's superconducting quantum computer and carry out the time evolution of the spin chain by employing the first-order Trotterization. Furthermore, our implementation of the second-order Trotterization for the isotropic Heisenberg spin chain, involving only nearest-neighbor exchange interaction, enables precise measurement of the expectation values of staggered magnetization observable across a range of up to 100 qubits. Notably, in both cases, our approach results in a constant circuit depth in each Trotter step, independent of the number of qubits. Our demonstration of the accurate measurement of expectation values for the large-scale quantum system using superconducting quantum computers designates the quantum utility of these devices for investigating various properties of many-body quantum systems. This will be a stepping stone to achieving the quantum advantage over classical ones in simulating quantum systems before the fault tolerance quantum era. Published by the American Physical Society 2024

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2025

Circularity in polydiketoenamine thermoplastics via control over reactive chain conformation

Controlling the reactivity of bonds along polymer chains enables both functionalization and deconstruction with relevance to chemical recycling and circularity. Because the substrate is a macromolecule, however, understanding the effects of chain conformation on the reactivity of polymer bonds emerges as important yet underexplored. Here, we show how oxy-functionalization of chemically recyclable condensation polymers affects acidolysis to monomers through control over distortion and interaction energies in the rate-limiting transition states. Oxy-functionalization of polydiketoenamines at specific sites on either the amine or triketone monomer segments increased acidolysis rates by more than three orders of magnitude, opening the door to efficient deconstruction of linear chain architectures. These insights substantially broaden the scope of applications for polydiketoenamines in a circular manufacturing economy, including chemically recyclable adhesives for a diverse range of surfaces.

Science & Technology - Other Topics↗

DOE OSTI2025

Analyzing Trip Chaining Behavior in New York State Using 2009 and 2017 National Household Travel Survey

Trip chaining, defined as the sequential linking of trips by individuals throughout a given day, provides critical insights into daily mobility patterns and activity sequencing. Understanding these patterns has significant implications for transportation demand forecasting, congestion management, and local economic activity. This analysis examines trip chaining behaviors in New York State (NYS) for the years 2009 and 2017 and compares the Middle Atlantic Census Division with other U.S. regions in 2022, utilizing data from the National Household Travel Survey (NHTS). Through demographic, geographic, and temporal analysis, this study characterizes how populations organize travel for work, personal errands, and social activities, providing empirical evidence of evolving trip chaining behaviors to inform transportation planning strategies.

99 GENERAL AND MISCELLANEOUS↗

DOE OSTI2025

Alpha Decay Chains as Thermal Power Sources: Analysis and Applications for RTGs

Radioactive sources can provide power in remote and environmentally harsh locations such as the arctic or space. The generators powered by such sources are rugged and can withstand extreme temperatures, lack of sunlight, and require no human intervention for multiple years. Radioisotopes are used in thermoelectric generators to provide power at remote sites and deep in space. Isotopes like Pu-238, Cm-244, and Am-241 are used in these generators by NASA for power in space probes and spacecrafts. These power sources deliver a steady supply of energy over extended periods of time. Alpha particles created during decay do not travel far in a material. Their kinetic energy is transferred to heat that we can then convert into energy. Unlike beta and gamma decay, the slower-moving alpha particles stop in the material, making their energy available for use. Energy from these natural decay processes provides a reliable source of power. Spontaneous fission is rare and unreliable, and unlike induced fission processes, alpha decay occurs naturally and does not require external management or ignition. The ideal properties of an isotope for use as a power source depend upon the intended use. For use in an Arctic research base over a period of several years, but less than a decade, an isotope that provides high power output over a shorter lifespan may be the most suitable option. Whereas, for deep space missions where a consistent power source for decades or perhaps more than 100 years is needed that would require a very different isotope. One with a much longer half-life that would provide consistent power throughout that time and survive in that state in for these extended periods of time. These examples represent two extreme sides in terms of time frames. By analyzing the power produced by different radioactive decay processes over time, we can evaluate the suitability of various isotope decay chains for specific uses. Some unstable isotopes undergo a series of radioactive decays, transforming into different isotopes at each step and resulting in a stable isotope. The lists of isotopes in these decay processes are known as decay chains. Some of these chains, illustrated in the figures below, are currently being investigated for use in radioisotope thermoelectric generators (RTGs) designed for a range of operational durations.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2026

Data Center Cybersecurity, Supply Chain Risk Management, and Emerging Regulation Cohort Summary: Takeaways and Action Plans

This report summarizes the outcomes of the Data Center Cohort under the Department of Energy’s Technical Assistance for Digital Assurance (TADA) initiative, aimed at enhancing grid resilience through cybersecurity, supply chain risk management (SCRM), and Cyber-Informed Engineering (CIE). The cohort engaged 17 organizations across utilities, data center operators, vendors, and technology providers in three sessions combining presentations, discussions, and exercises. Key topics included AI-driven load behavior, cybersecurity vulnerabilities in UPS/BESS and cooling systems, governance gaps at utility–data center boundaries, and supply chain integrity. Five cross-cutting themes emerged: interconnection architecture vulnerabilities, fragmented governance, AI-driven stability risks, lack of regulatory frameworks, and long-term supply chain concerns. Actionable recommendations were developed, including implementing DMZ segmentation, formalizing vendor access agreements, designing AI workload limits, and advancing standards through NERC and state-level programs. These strategies aim to strengthen resilience, clarify responsibilities, and ensure secure integration of data centers into the grid.

24 - POWER TRANSMISSION AND DISTRIBUTION↗

DOE OSTI2024

PET and polyolefin plastics supply chains in Michigan: present and future systems analysis of environmental and socio-economic impacts

Many actions are underway at global, national, and local levels to increase plastics circularity. However, studies evaluating the environmental and socio-economic impacts of such a transition are lacking at regional levels in the United States. In this work, the existing polyethylene terephthalate and polyolefin plastics supply chains in Michigan were compared to a potential future (‘NextCycle’) scenario that looks at increasing Michigan’s overall recycling rate to 45%. Material flow analysis data was combined with environmental and socio-economic metrics to evaluate the sustainability of these supply chains for the modeled scenarios. Overall, the NextCycle scenario for these supply chains achieved a net 14% and 34% savings of greenhouse gas (GHG) emissions and energy impacts, when compared with their respective baseline values. Additionally, the NextCycle scenario showed a net gain in employment and wages, however, it showed a net loss of revenue generation outside of Michigan due to the avoided use of virgin resins in Michigan.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2024

North America’s Potential for an Environmentally Sustainable Nickel, Manganese, and Cobalt Battery Value Chain

The Detroit Big Three General Motors (GMs), Ford, and Stellantis predict that electric vehicle (EV) sales will comprise 40–50% of the annual vehicle sales by 2030. Among the key components of LIBs, the LiNixMnyCo1−x−yO2 cathode, which comprises nickel, manganese, and cobalt (NMC) in various stoichiometric ratios, is widely used in EV batteries. This review reveals NMC cathodes from laboratory research. Furthermore, this study examines the environmental effect of NMC cathode production for EV batteries (including coating technologies), encompassing aspects such as energy consumption, water usage, and air emissions. Although gaps persist in NMC cathode environmental assessments (NMC111, NMC532, NMC622, and NMC811), limited life cycle assessments “(LCA)” have been conducted. Most available data originate from Asia (primarily China), accounting for 85% of the production of EV LIB cathode materials. The concept of battery passports for data collection on LIB components has been proposed to facilitate material traceability as a system for ensuring a sustainable supply chain for critical minerals. The automotive industry’s shift to electrification necessitates a sustainable supply chain from mine to vehicle end-of-life. As the critical mineral supply moves from Asia to North America, environmentally friendly industrial methods must be studied to provide this supply chain direction.

25 ENERGY STORAGE↗

DOE OSTI2024

Double-Helical Tiled Chain Structure of the Twist-Bend Liquid Crystal Phase in CB7CB

The twist-bend nematic liquid crystal phase is a three-dimensional fluid in which achiral bent molecules spontaneously form an orientationally ordered, macroscopically chiral, heliconical winding of a ten nanometer-scale pitch in the absence of positional ordering. Here, the structure of the twist-bend phase of the bent dimer CB7CB and its mixtures with 5CB is characterized, revealing a hidden invariance of the self-assembly of the twist-bend structure of CB7CB, such that over a wide range of concentrations and temperatures, the helix pitch and cone angle change as if the ground state for a pitch of the TB helix is an inextensible heliconical ribbon along the contour formed by following the local molecular long axis (the director). Remarkably, the distance along the length for a single turn of this helix is given by 2πR mol , where R mol is the radius of bend curvature of a single all-trans CB7CB molecule. This relationship emerges from frustrated steric packing due to the bent molecular shape: space in the fluid that is hard to fill attracts the most flexible molecular subcomponents, a theme of nanosegregation that generates self-assembled, oligomer-like correlations of interlocking bent molecules in the form of a brickwork-like tiling of pairs of molecular strands into duplex double-helical chains. At higher temperatures in the twist-bend phase, the cone angle is small, the director contour is nearly along the helix axis z, and the duplex chains are sequences of biaxial elements formed by overlapping half-molecule pairs, with an approximately 45° rotation of the biaxis between each such element along the chain.

36 MATERIALS SCIENCE↗

NASA NTRS1972

New polymer systems: Chain extension by dianhydrides

The results are presented for a systematic investigation on the use of anhydrides to prepare stable elastomeric materials for space use, under mild reaction conditions. The three anhydrides investigated were found to provide effective chain extension of hydroxy-terminated poly(alkylene oxides) and poly(butadienes). These were tetrahydrofuran tetracarboxylic dianhydride, pyromellitic dianhydride, and benzophenone tetracarboxylic diahydride. The most effective catalyst investigated was ferric acetylacetonate, which resulted in chain extension at 333 K (60 C). One feature of these anhydride reactants is that they are difunctional as anhydrides, but tetrafunctional if conditions are selected that lead to reaction of all carboxyl groups. Therefore, chain extension can be effected and then followed by crosslinking via the residual carboxyl groups.

Rhein, R. A.↗

NASA NTRS1971

Comparisons of the polypeptide chains of globins.

Discussion of the amino acid differences and minimum base differences per codon due to mutations which took place during divergent evolution of vertebrates from a common ancestral gene. The ?random mutation model' of evolution is examined by comparing a carp alpha Hb chain and six mammalian alpha Hb chains in terms of the genetic code. The occurrence of recognizable three-base changes is analyzed and a summary of the distribution of changes in the hemoglobin and myoglobin chains is given for 148 sites.

Jukes, T. H.↗

NASA NTRS1974

The Mendeleev Crater chain: A description and discussion of origin

A 113-kilometer-long crater chain on the floor of Mendeleev Crater is the best morphological example of several similar chains on the lunar far side. Age relationships relative to Mendeleev Crater indicate that it is a younger feature that may have developed over a fault parallel to the lunar grid system. The dumbbell shape of the chain may be related to a differential stress along a fault crossing the floor that resulted in varying resistance to magma invasion.

Eppler, D.↗

NASA NTRS1974

Laboratory simulation of the herringbone pattern associated with lunar secondary crater chains

V-shaped ridge components of the herringbone pattern associated with lunar secondary crater chains have been simulated by simultaneous and nearly simultaneous impact of two projectiles near one another. The impact velocities and angles of the projectiles were similar to those of the fragments that produced secondary craters found at various ranges from large lunar craters. Variables found to affect the included angles of the V-shaped ridges are: relative time of impact of the projectiles, impact angle, relative projectile mass, and azimuth angle of the crater chain relative to the projection of the flight line onto the target surface. The functional relationships between the forms of the ridges and many of these variables are similar to those observed for lunar V-shaped ridges. Comparison of the magnitudes of the ridge angles of both laboratory crater pairs and secondary crater chains of the crater Copernicus implies that material was ejected from Copernicus at angles in excess of 60 deg, measured from the normal, to form many of Copernicus' satellite craters.

Oberbeck, V. R.↗

NASA NTRS1974

On the dynamics of chain systems

A computer-oriented method for obtaining dynamical equations of motion for chain systems is presented. A chain system is defined as an arbitrarily assembled set of rigid bodies such that adjoining bodies have at least one common point and such that closed loops are not formed. The equations of motion are developed through the use of Lagrange's form of d'Alembert's principle. The method and procedure is illustrated with an elementary study of a tripod space manipulator. The method is designed for application with systems such as human body models, chains and cables, and dynamic finite-segment models.

Huston, R. L.↗

NASA NTRS1976

Comparison of chain sampling plans with single and double sampling plans

The efficiency of chain sampling is examined through matching of operating characteristics (OC) curves of chain sampling plans (ChSP) with single and double sampling plans. In particular, the operating characteristics of some ChSP-0, 3 and 1, 3 as well as ChSP-0, 4 and 1, 4 are presented, where the number pairs represent the first and the second cumulative acceptance numbers. The fact that the ChSP procedure uses cumulative results from two or more samples and that the parameters can be varied to produce a wide variety of operating characteristics raises the question whether it may be possible for such plans to provide a given protection with less inspection than with single or double sampling plans. The operating ratio values reported illustrate the possibilities of matching single and double sampling plans with ChSP. It is shown that chain sampling plans provide improved efficiency over single and double sampling plans having substantially the same operating characteristics.

Stephens, K. S.↗