Dynamic Membrane Materials from Amphiphilic Block Copolymers.
Abstract not provided.
Paxton, Walter F↗
SEARCH · Engineering Papers
Results for “materials dynamics”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Constant-depth circuits for dynamic simulations of materials on quantum computers
Abstract Dynamic simulation of materials is a promising application for near-term quantum computers. Current algorithms for Hamiltonian simulation, however, produce circuits that grow in depth with increasing simulation time, limiting feasible simulations to short-time dynamics. Here, we present a method for generating circuits that are constant in depth with increasing simulation time for a specific subset of one-dimensional (1D) materials Hamiltonians, thereby enabling simulations out to arbitrarily long times. Furthermore, by removing the effective limit on the number of feasibly simulatable time-steps, the constant-depth circuits enable Trotter error to be made negligibly small by allowing simulations to be broken into arbitrarily many time-steps. For an N -spin system, the constant-depth circuit contains only $\mathcal {O}(N^{2})$ O ( N 2 ) CNOT gates. Such compact circuits enable us to successfully execute long-time dynamic simulation of ubiquitous models, such as the transverse field Ising and XY models, on current quantum hardware for systems of up to 5 qubits without the need for complex error mitigation techniques. Aside from enabling long-time dynamic simulations with minimal Trotter error for a specific subset of 1D Hamiltonians, our constant-depth circuits can advance materials simulations on quantum computers more broadly in a number of indirect ways.
Materials simulation↗
Learning with Delayed Rewards—A Case Study on Inverse Defect Design in 2D Materials
Defect dynamics in materials are of central importance to a broad range of technologies from catalysis to energy storage systems to microelectronics. Material functionality depends strongly on the nature and organization of defects-their arrangements often involve intermediate or transient states that present a high barrier for transformation. The lack of knowledge of these intermediate states and the presence of this energy barrier presents a serious challenge for inverse defect design, especially for gradient-based approaches. Here, we present a reinforcement learning (RL) [Monte Carlo Tree Search (MCTS)] based on delayed rewards that allow for efficient search of the defect configurational space and allows us to identify optimal defect arrangements in low-dimensional materials. Using a representative case of two-dimensional MoS 2 , we demonstrate that the use of delayed rewards allows us to efficiently sample the defect configurational space and overcome the energy barrier for a wide range of defect concentrations (from 1.5 to 8% S vacancies)-the system evolves from an initial randomly distributed S vacancies to one with extended S line defects consistent with previous experimental studies. Detailed analysis in the feature space allows us to identify the optimal pathways for this defect transformation and arrangement. Comparison with other global optimization schemes like genetic algorithms suggests that the MCTS with delayed rewards takes fewer evaluations and arrives at a better quality of the solution. The implications of the various sampled defect configurations on the 2H to 1T phase transitions in MoS 2 are discussed. In this study, we introduce a RL strategy employing delayed rewards that can accelerate the inverse design of defects in materials for achieving targeted functionality.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Enhanced Dual Confocal Measurement System
A measurement instrument utilizing dual, chromatic, confocal, distance sensors has been jointly developed by General Atomics (GA) and Sandia National Laboratories (SNL) for thickness and flatness measurement of target components used in dynamic materials properties (DMP) experiments on the SNL Z-Machine (Z). Compared to previous methods used in production of these types of targets, the tool saves time and yields a 4x reduction in thickness uncertainty which is one of the largest sources of error in equation of state (EOS) measurements critical to supporting the NNSA’s Stockpile Stewardship program and computer modeling of high energy density experiments. It has numerous differences from earlier instruments operating on the dual confocal sensor principle to accommodate DMP components including larger lateral travel, longer working distance, ability to measure flatness in addition to thickness, built-in thickness calibration standards for quickly checking calibration before and after each measurement, and streamlined operation. Thickness and flatness of 0.2mm-3.3mm thick sections of diamond machined copper and aluminum can be measured to “sub-micron” accuracy. Sections up to 6mm thick can be measured with as-yet undermined accuracy. Furthermore, samples must have one surface which is flat to within 300µm, lateral dimensions of no more than 50mm x 50mm, and height less than 40mm.
36 MATERIALS SCIENCE↗
A Novel Approach for Plate Impact Experiments to Determine the Dynamic Behavior of Materials Under Extreme Conditions
Here we present a unique approach to plate impact experiments for characterization of dynamic material behavior under extreme conditions, i.e., ultra-high strain-rates (~10 6 /s) and test temperatures up to 1000 °C. Strategic modifications are made to the existing singlestage gas-gun facility at CWRU to enable this approach. These include an extension of the gun barrel at the breech end of the gas-gun, which now incorporates a precision machined steel housing that carries a vertical heater well to accommodate an 800 W resistance coil heater with axial and rotational degrees of freedom. This custom designed heater assembly enables specimens placed on the flyer plate carried by the sabot to be heated uniformly across the diameter in a 100 mTorr vacuum prior to impact at the breech end of the gun barrel. A new sabot design is utilized to minimize heat transfer from the heated flyer plate to the sabot body. Using this modified gas-gun facility, the dynamic strength of pre-heated commercial purity polycrystalline aluminum samples is investigated at the onset of plastic flow in response to weak normal shock compression at test temperatures ranging from room to near melt point of aluminum. Lastly, the dynamic strength of aluminum samples, as inferred from the measured normal particle velocity history at the free (rear) surface of the target plate, show progressive weakening with increasing specimen temperatures in the temperature range 23–643 °C; at higher test temperatures, however, the rate of softening in dynamic strength is observed to weaken and even reverse as the sample temperatures approach the melt point of aluminum (test temperature ~643 °C).
36 MATERIALS SCIENCE↗
SU-E-J-194: Dynamic Tumor Tracking End-To-End Testing Using a 4D Thorax Phantom and EBT3 Films
Purpose: To quantify the Vero linac dosimetric accuracy of the tumor dynamic tracking treatment using EBT3 film embedded in a 4D thorax phantom. Methods: A dynamic thorax phantom with tissue equivalent materials and a film insert were used in this study. The thorax phantom was scanned in 4DCT mode with a viscoil embedded in its film insert composed of lung equivalent material. Dynamic tracking planning was performed using the 50% phase CT set with 5 conformal beams at gantry angles of 330, 15, 60, 105 and 150 degrees. Each field is a 3cm by 3cm square centered at viscoil since there was no solid mass target. Total 3 different 1–2cos4 motion profiles were used with varied motion magnitude and cycle frequency. Before treatment plan irradiation, a 4D motion model of the target was established using a series of acquired fluoroscopic images and infrared markers motion positions. During irradiation, fluoroscopic image monitoring viscoil motion was performed to verify model validity. The irradiated films were scanned and the dose maps were compared to the planned Monte Carlo dose distributions. Gamma analyses using 3%–3mm, 2%–3mm, 3%–2mm, 2%–2mm criteria were performed and presented. Results: For each motion pattern, a 4D motion model was built successfully and the target tracking performance was verified with fluoroscopic monitoring of the viscoil motion and its model predicted locations. The film gamma analysis showed the average pass rates among the 3 motion profiles are 98.14%, 96.2%, 91.3% and 85.61% for 3%–3mm, 2%–3mm, 3%–2mm, 2%–2mm criteria. Conclusion: Target dynamic tracking was performed using patient-like breathing patterns in a 4D thorax phantom with EBT3 film insert and a viscoil. There was excellent agreement between acquired and planned dose distributions for all three target motion patterns. This study performed end-to-end testing and verified the treatment accuracy of tumor dynamic tracking.
60 APPLIED LIFE SCIENCES↗
Mechanical properties, deformation behavior and microstructure evolution of Ti-43Al-6Nb-1Mo-1Cr alloys
Highlights: • The alloys exhibit excellent high-temperature tensile properties. • Activation energy of deformation (Q) and n are 571 KJ/mol and 2.765, respectively. • The hot processing maps of strain 0.5 and 0.6 are displayed. • Phase transformations and microstructure evolution are explained in different conditions. • Three types of deformation mechanisms are exhibited at different temperature. - Abstract: The high-temperature properties, microstructure evolution and deformation behavior of a novel Ti-43Al-6Nb-1Mo-1Cr(at.%) alloy were studied in this paper. The ultimate tensile strength (UTS) and elongation (δ) were tested at 800, 850, and 900 °C, in which the excellent strength 551 MPa, 510 MPa, and 382 MPa, and elongation 2.9%, 12.7%, and 16.8% were exhibited, respectively. Isothermal compression tests were carried out in the temperature range of 1100–1250 °C and strain rate range of 0.001–1.0 s{sup − 1}. Based on dynamic materials model (DMM) and phase diagram, dynamic recrystallization mechanism and phase transformation during thermal deformation were clarified and the hot processing maps were calculated. The experimental results show that the values of stress exponent (n) and the apparent deformation activation energy (Q) of Ti-43Al-6Nb-1Mo-1Cr(at.%) were calculated to be 2.77 and 571 KJ/mol. Meanwhile, three various types of microstructure evolution in different deformation conditions were discussed and concluded.
36 MATERIALS SCIENCE↗
Fast MAS 1 H– 13 C correlation NMR for structural investigations of plant cell walls
Plant cell walls consist of a mixture of polysaccharides that render the cell wall a strong and dynamic material. Understanding the molecular structure and dynamics of wall polysaccharides is important for understanding and improving the properties of this energy-rich biomaterial. So far, solid-state NMR studies of cell wall structure and dynamics have solely relied on 13 C chemical shifts measured from 2D and 3D correlation experiments. To increase the spectral resolution, sensitivity and upper limit of measurable distances, it is of interest to explore 1 H chemical shifts and 1 H-detected NMR experiments for analyzing cell walls. Here we demonstrate 2D and 3D 1 H– 13 C correlation experiments at both moderate and fast MAS frequencies of 10–50 kHz to resolve and assign 1 H chemical shifts of matrix polysaccharides in Arabidopsis primary cell walls. Here, both 13 C-detected and 1 H-detected experiments are implemented and are shown to provide useful and complementary information. Using the assigned 1 H chemical shifts, we measured long-range correlations between matrix polysaccharides and cellulose using 1 H– 1 H instead of 13 C– 13 C spin diffusion, and the 2D experiments can be conducted with either 13 C or 1 H detection.
1H chemical shift↗
Microstructural Changes to Thermally Sprayed Materials Subjected to Dynamic Compression
Dynamic compression of materials can induce a variety of microstructural changes. As thermally-sprayed materials have highly complex microstructures, the expected pressure at which changes occur cannot be predicted a priori. In addition, typical in-situ measurements such as velocimetry are unable to adequately diagnose microstructural changes such as failure or pore collapse. Quasi-isentropic compression experiments with sample recovery were conducted to examine microstructural changes in thermally sprayed tantalum and tantalum-niobium blends up to 8 GPa pressure. Spall fracture was observed in all tests, and post-shot pore volume decreased relative to the initial state. The blended material exhibited larger spall planes with fracture occurring at interphase boundaries. An estimate of the pressure at which pore collapse is complete was determined to be ~26 GPa for pure tantalum and ~19 GPa for the tantalumniobium blend under these loading conditions.
36 MATERIALS SCIENCE↗
Anticipating impacts of introducing aluminum-cerium alloys into the United States automotive market
Increasing demand of abundant co-product rare earths such as cerium and lanthanum has become a focus for improving mine economics. The recent development of an aluminum-cerium (Al-Ce) alloy targeted toward broad market adoption in the automotive industry is one recent example. This alloy has shown exceptional mechanical properties and cost-saving potential. However, since market adoption is unknown, impacts of this alloy on Ce demand remains uncertain. We estimate Al-Ce impacts by simulating adoption in different automotive sectors using a dynamic material flow analysis model. We then project future Ce content in the recycled Al stream given current recycling practices. We also compute the required segregation given different Ce impurity tolerances of existing automotive Al alloys. Finally, once secondary supply is derived from segregation, we calculate primary Ce demand. Results showed that segregation of Al-Ce components from non-AlCe automotive Al components is needed for most adoption scenarios and impurity thresholds. Ce metal demand was found to be lowest at 1000 mt/yr if the target market is light duty trucks. If Al-Ce could penetrate the High Efficiency Spark Ignition market (i.e., turbocharger market), Ce demand could reach 23,200 mt Ce/year in 2045, without accounting for Chinese and Australian Ce primary production capacity. Furthermore, when accounting for primary Ce production capacity, demand could reach up to 16,200 mt/yr.
99 GENERAL AND MISCELLANEOUS↗
Project DarkStar: Vision for LLNL in 2030
DarkStar was a Strategic Initiative (FY2021-FY2024) to investigate applications of Artificial Intelligence (AI) and Machine Learning (ML) to scientific problems of complex hydrodynamics, shockwave physics and energetic materials. The research focused on physics and engineering design as a process that can be tremendously accelerated through merging AI with advanced physics simulation on exascale-class platforms, and to experimentally validate this revolutionary new approach through dynamic materials campaigns. A central thread of scientific inquiry was in the application of AI to enable human understanding of how to control hydrodynamic instability (which has impacts to areas such as inertial confinement fusion) via engineering features and time-dependent sources. Motivated by an unfinished line of research started by Dr. Johnny von Neumann, AI-enabled simulation approaches were developed that allowed DarkStar researchers to uncover several ground-breaking discoveries regarding hydrodynamic instability, including how to completely suppress Richtmyer-Meshkov instability (RMI). These S&T discoveries, along with other advances, have shown the way for an entirely new approach to time-dependent problems known as inverse design – the idea that complex systems can be developed directly from a final state that is to be achieved and resolve the initial design via satisfying several constraints simultaneously via AI/ML. Through experimental campaigns conducted across a wide range of facilities in the NNSA complex (the High Explosive Application Facility at LLNL, the Dynamic Compression Sector/Advanced Photon Source at Argonne National Lab, and Special Technologies Laboratory at MSTS) the radical new AI/ML approach to engineering complex material dynamics was verified, establishing a new field of study within the realm of shock physics. As advanced manufacturing capabilities continue to develop, the great importance of inverse design as a means to apply that technology effectively for NNSA missions will feature prominently over this decade. DarkStar has positioned NNSA as a world-leader in this newly emerging cross-disciplinary area of AI methods for advanced physics simulation and pioneered multiple novel approaches that have enabled the broader scientific community. By allowing us to see past the horizon, to 2030 and beyond, DarkStar has illuminated the vast potential of AI/ML to impact a wide range of new national security missions and, consequently, multiple areas of further research have already emerged across the NNSA and DOD complex.
42 ENGINEERING↗
Dislocation dynamics in polycrystalline materials
An extension of the dislocation dynamics method to polycrystalline materials is presented with emphasis on handling interactions between dislocations and grain boundaries. The key new features of the method include: (1) a grain boundary detection algorithm, (2) new dislocation emission criteria based on power dissipation and area growth, (3) mobility of dislocations at grain boundaries, and (4) extension of topological operations e.g. mesh adaption, collision, and dissociation to handle dislocations interacting with grain boundaries. Furthermore, verification and validation examples are executed to compare our calculations with existing analytic methods, molecular dynamics simulations, and experimental observations.
36 MATERIALS SCIENCE↗
Flight-vehicle materials, structures, and dynamics - Assessment and future directions. Vol. 4 - Tribological materials and NDE
The present volume on tribological materials and NDE discusses liquid lubricants for advanced aircraft engines, a liquid lubricant for space applications, solid lubricants for aeronautics, and thin solid-lubricant films in space. Attention is given to the science and technology of NDE, tools for an NDE engineering base, experimental techniques in ultrasonics for NDE and material characterization, and laser ultrasonics. Topics addressed include thermal methods of NDE and quality control, digital radiography in the aerospace industry, materials characterization by ultrasonic methods, and NDE of ceramics and ceramic composites. Also discussed are smart materials and structures, intelligent processing of materials, implementation of NDE technology on flight structures, and solid-state weld evaluation.
Fusaro, Robert L.↗
In Situ Experimental Capabilities and Results from the X-ray Powder Diffraction Beamline
The world-leading intensity and brightness of the NSLS-II at Brookhaven National Laboratory offers unique opportunities for studying materials for nuclear energy systems under prototypical operating conditions, i.e, in situ. Probing the microstructural evolution in situ is essential to understand both the fundamental material dynamics and to develop physically relent predictive material performance models for operation in the extreme environments of nuclear reactors. This presentation describes the unique opportunities for in situ experiments at the X-ray Powder Diffraction beamline (XPD) that are planned to be accessed through The Nuclear Science User Facilities (NSUF). Examples of recent in situ experiments at XPD are given for three different materials systems including; field assisted sintering of UO{sub 2}; phase evolution in high Ni-Cr alloys, and the corrosion of Zircaloy.
36 MATERIALS SCIENCE↗
Visualization of shocked material instabilities using a fast-framing camera and XFEL four-pulse train
Many questions regarding dynamic materials could be answered by using time-resolved ultra-fast imaging techniques to characterize the physical and chemical behavior of materials in extreme conditions and their evolution on the nanosecond scale. In this work, we perform multi-frame phase-contrast imaging (PCI) of micro-voids in low density polymers under laser-driven shock compression. At the Matter in Extreme Conditions (MEC) Instrument at the Linac Coherent Light Source (LCLS), we used a train of four x-ray free electron laser (XFEL) pulses to probe the evolution of the samples. To visualize the void and shock wave interaction, here, we deployed the Icarus V2 detector to record up to four XFEL pulses, separated by 1-3 nanoseconds. In this work, we image elastic waves interacting with the micro-voids at a pressure of several GPa. Monitoring how the material’s heterogeneities, like micro-voids, dictate its response to a compressive wave is important for benchmarking the performances of inertial confinement fusion energy materials. For the first time in a single sample, we have combined an ultrafast x-ray framing camera and four XFEL pulse train to create an ultrafast movie of micro-void evolution under laser-driven shock compression. Eventually, we hope this technique will resolve the material density as it evolves dynamically under laser shock compression.
fusion↗
Understanding curing dynamics of arylacetylene and phthalonitrile thermoset blends
Tetrakis(phenylethynyl)benzene (TPEB), a high char yield arylacetylene resin, was blended with a resorcinol-based PEEK™-like oligomeric phthalonitrile resin (Res). Here, we observed the influence of each polymer precursor on the structural changes and material dynamics of different mixtures of these resins during thermal curing to produce thermosets with high char retention. We provide insight to help understand fundamental processes that control and tune this complex thermally driven curing mechanism, which, to date, has not been well understood. We show that an equivalent blend of Res and TPEB mitigates the exothermic curing process and exhibits a low viscosity, which may facilitate processing of these thermosetting blends for composite manufacturing. To obtain a more comprehensive overview of the different dynamics of these polymers during curing, we correlated thermodynamic changes with rheology, materials characterization, and molecular dynamics derived from neutron scattering. Our efforts shed more light on the thermally driven chemical changes, physical transformation, and gelation dynamics that drive or accompany softening and curing of these two distinct crosslinking resin groups.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Characterization of Thin Film Polymers Through Dynamic Mechanical Analysis and Permeation
Thin polymer films are being considered, as candidate materials to augment the permeation resistance of cryogenic hydrogen fuel tanks such as would be required for future reusable launch vehicles. To evaluate performance of candidate films after environmental exposure, an experimental study was performed to measure the thermal/mechanical and permeation performance of six, commercial-grade materials. Dynamic storage modulus, as measured by Dynamic Mechanical Analysis, was found over a range of temperatures. Permeability, as measured by helium gas diffusion, was found at room temperature. Test data was correlated with respect to film type and pre-test exposure to moisture, elevated temperature, and cryogenic temperature. Results indicated that the six films were comparable in performance and their resistance to environmental degradation.
Herring, Helen↗