Search NASA⌕ Search

SEARCH · Search NASA

Results for “dynamic characterization”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,693 records · Page 94
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Dynamic entity formed by protein and its hydration water

The interaction between protein and water plays a pivotal role in shaping the structure, dynamics, and function of biomacromolecules. A comprehensive understanding of this intricate interplay necessitates a systematic evaluation of interaction strength and its consequential impact on the dynamics of proteins and water across diverse protein systems. Despite numerous works on understanding the dynamics of water and proteins and the coupling between them, there are still unanswered questions. Here, we combine neutron scattering and isotope labeling to probe the dynamics of proteins and their hydration water in a variety of protein systems. We consider proteins of different structures and varying thermostability as well as proteins within living cells with distinct growth temperatures. Simultaneous characterization of protein and hydration water dynamics across diverse systems was achieved. Moreover, we performed water sorption isothermal measurements on three representative proteins to correlate the observed dynamics with the strength of the interaction energies governing each system. The experimental results underscore that proteins manifesting stronger attractive interactions with water display diffusionlike dynamics with higher flexibility upon hydration, concomitant with a reduced mobility in hydration water. Significantly, our findings suggest that, in fact, it is the interaction between protein and its hydration water that facilitates the transfer of mobility from water to protein, with stronger interactions correlating to greater protein flexibility and slower hydration water diffusion. Published by the American Physical Society 2024

Ye, Yongfeng (ORCID:0009000792374198)↗
NASA NTRS2007

Integrated System Test Approaches for the NASA Ares I Crew Launch Vehicle

The Ares I Crew Launch Vehicle (CLV) is being developed by the U.S. National Aeronautics and Space Administration (NASA) to provide crew access to the International Space Station (ISS) and, together with the Ares V Cargo Launch Vehicle (CaLV), serves as one component of a future launch capability for human exploration of the Moon. During the system requirements definition process and early design cycles, NASA defined and began implementing plans for integrated ground and flight testing necessary to achieve the first human launch of Ares I. The individual Ares I flight hardware elements: the first stage five segment booster (FSB), upper stage, and J-2X upper stage engine, will undergo extensive development, qualification, and certification testing prior to flight. Key integrated system tests include the Main Propulsion Test Article (MPTA), acceptance tests of the integrated upper stage and upper stage engine assembly, a full-scale integrated vehicle dynamic test (IVDT), aerodynamic testing to characterize vehicle performance, and integrated testing of the avionics and software components. The Ares I-X development flight test will provide flight data to validate engineering models for aerodynamic performance, stage separation, structural dynamic performance, and control system functionality. The Ares I-Y flight test will validate ascent performance of the first stage, stage separation functionality, and a highaltitude actuation of the launch abort system (LAS) following separation. The Orion-1 flight test will be conducted as a full, un-crewed, operational flight test through the entire ascent flight profile prior to the first crewed launch.

Cockrell, Charles E., Jr.↗
DOE OSTI2017

Dynamic Scaling of Colloidal Gel Formation at Intermediate Concentrations

Here, we have examined the formation and dissolution of gels composed of intermediate volume-fraction nanoparticles with temperature-dependent short-range attractions using small-angle x-ray scatter- ing (SAXS), x-ray photon correlation spectroscopy (XPCS), and rheology to obtain nanoscale and macroscale sensitivity to structure and dynamics. Gel formation after temperature quenches to the vicinity of the rheologically-determined gel temperature, T gel , was characterized via the slow-down of dynamics and changes in microstructure observed in the intensity autocorrelation functions and structure factor, respectively, as a function of quench depth (ΔT = T quench - T gel ), wave vector, and formation time (t f ). We find similar patterns in the slow-down of dynamics that maps the wave-vector-dependent dynamics at a particular ΔT and t f to that at other ΔTs and t f s via an effective scaling temperature, Ts. A single Ts applies to a broad range of ΔT and tf but does depend on the particle size. The rate of formation implied by the scaling is a far stronger function of ΔT than that of the attraction strength between colloids. Finally, we interpret this strong temperature de- pendence in terms of changes in cooperative bonding required to form stable, energetically favored, local structures.

42 ENGINEERING↗
DOE OSTI2011

Laboratory Studies of Spontaneous Reconnection and Intermittent Plasma Objects (Final Report)

The study of the collisionless magnetic reconnection constituted the primary work carried out under this grant. The investigations utilized two magnetic configurations with distinct boundary conditions. Both configurations were based upon the Versatile Toroidal Facility (VTF) at the MIT Plasma Science and Fusion Center and the MIT Physics Department. The NSF/DOE award No. 0613734, supported two graduate students (now Drs. W. Fox and N. Katz) and material expenses. The grant enabled these students to operate the VTF basic plasma physics experiment on magnetic reconnection. The first configuration was characterized by open boundary conditions where the magnetic field lines interface directly with the vacuum vessel walls. The reconnection dynamics for this configuration has been methodically characterized and it has been shown that kinetic effects related to trapped electron trajectories are responsible for the high rates of reconnection observed. This type of reconnection has not been investigated before. Nevertheless, the results are directly relevant to observations by the Wind spacecraft of fast reconnection deep in the Earth magnetotail. The second configuration was developed to be relevant to specifically to numerical simulations of magnetic reconnection, allowing the magnetic field-lines to be contained inside the device. The configuration is compatible with the presence of large current sheets in the reconnection region and reconnection is observed in fast powerful bursts. These reconnection events facilitate the first experimental investigations of the physics governing the spontaneous onset of fast reconnection. In the Report we review the general motivation of this work and provide an overview of our experimental and theoretical results enabled by the support through the awards.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Dynamic Strength and Equation of State of Epon 828 and Diethanolamine (DEA) Polymer Epoxy Under Shock Loading

Polymers are increasingly utilized in engineering applications that can experience high loading rates, necessitating increased understanding of their response under such conditions. The tamped Richtmyer-Meshkov Instability (RMI) method was used to characterize the equation of state and dynamic strength of the polymer Epon 828 cured with Diethanolamine (DEA). Plate impact experiments that drove a uniaxial shock compression wave across a sinusoidally corrugated metal-polymer interface were performed to generate shock stresses from 4-12 GPa and strain rates of approximately 1/s in the polymer. X-ray phase contrast imaging recorded the shock motion in the polymer and subsequent interface evolution. Analysis of this data yielded the polymer equation of state and, in conjunction with numerical modeling, the dynamic strength. The equation of state was validated against one-dimensional plate impact experiments from existing literature. The dynamic strength was compared to prior data for Epon 828 and related polymers at lower strain rates and found to exhibit significant strain rate and pressure-hardening effects. The strength of the Epon 828 polymer at 10 6 1/s was found to be approximately 1.5 GPa, suggesting that it is comparable to the strength of high strength metals at these dynamic conditions.

Equation of state↗
DOE OSTI2017

Single-Molecule Interfacial Electron Transfer

This project is focused on the use of single-molecule high spatial and temporal resolved techniques to study molecular dynamics in condensed phase and at interfaces, especially, the complex reaction dynamics associated with electron and energy transfer rate processes. The complexity and inhomogeneity of the interfacial ET dynamics often present a major challenge for a molecular level comprehension of the intrinsically complex systems, which calls for both higher spatial and temporal resolutions at ultimate single-molecule and single-particle sensitivities. Combined single-molecule spectroscopy and electrochemical atomic force microscopy approaches are unique for heterogeneous and complex interfacial electron transfer systems because the static and dynamic inhomogeneities can be identified and characterized by studying one molecule at a specific nanoscale surface site at a time. The goal of our project is to integrate and apply these spectroscopic imaging and topographic scanning techniques to measure the energy flow and electron flow between molecules and substrate surfaces as a function of surface site geometry and molecular structure. We have been primarily focusing on studying interfacial electron transfer under ambient condition and electrolyte solution involving both single crystal and colloidal TiO 2 and related substrates. The resulting molecular level understanding of the fundamental interfacial electron transfer processes will be important for developing efficient light harvesting systems and broadly applicable to problems in fundamental chemistry and physics. We have made significant advancement on deciphering the underlying mechanism of the complex and inhomogeneous interfacial electron transfer dynamics in dyesensitized TiO 2 nanoparticle systems that strongly involves with and regulated by molecule-surface interactions. We have studied interfacial electron transfer on TiO 2 nanoparticle surfaces by using ultrafast single-molecule spectroscopy and electrochemical AFM metal tip scanning microscopy, focusing on understanding the interfacial electron transfer dynamics at specific nanoscale electron transfer sites with high-spatially and temporally resolved topographic-and-spectroscopic characterization at individual molecule basis, characterizing single-molecule rate processes, reaction driving force, and molecule-substrate electronic coupling. One of the most significant characteristics of our new approach is that we are able to interrogate the complex interfacial electron transfer dynamics by actively pin-point energetic manipulation of the surface interaction and electronic couplings, beyond the conventional excitation and observation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Quantitative Assessment of Transportation Network Vulnerability with Dynamic Traffic Simulation Methods

Transportation networks are critical to the social and economic function of nations. Given the continuing increase in the populations of cities throughout the world, the criticality of transportation infrastructure is expected to increase. Thus, it is ever more important to mitigate congestion as well as to assess the impact disruptions would have on individuals who depend on transportation for their work and livelihood. Moreover, several government organizations are responsible for ensuring transportation networks are available despite the constant threat of natural disasters and terrorist activities. Most of the previous transportation network vulnerability research has been performed in the context of static traffic models, many of which are formulated as traditional optimization problems. However, transportation networks are dynamic because their usage varies over time. Thus, more appropriate methods to characterize the vulnerability of transportation networks should consider their dynamic properties. This paper presents a quantitative approach to assess the vulnerability of a transportation network to disruptions with methods from traffic simulation. Our approach can prioritize the critical links over time and is generalizable to the case where both link and node disruptions are of concern. We illustrate the approach through a series of examples. Our results demonstrate that the approach provides quantitative insight into the time varying criticality of links. Such an approach could be used as the objective function of less traditional optimization methods that use simulation and other techniques to evaluate the relative utility of a particular network defense to reduce vulnerability and increase resilience.

Shekar, Venkateswaran↗
NASA NTRS2005

Soot Formation in Purely-Curved Premixed Flames and Laminar Flame Speeds of Soot-Forming Flames

The research addressed here is a collaborative project between University of Delaware and Case Western Reserve University. There are two basic and related scientific objectives. First, we wish to demonstrate the suitability of spherical/cylindrical, laminar, premixed flames in the fundamental study of the chemical and physical processes of soot formation. Our reasoning is that the flame standoff distance in spherical/cylindrical flames under microgravity can be substantially larger than that in a flat burner-stabilized flame. Therefore the spherical/cylindrical flame is expected to give better spatial resolution to probe the soot inception and growth chemistry than flat flames. Second, we wish to examine the feasibility of determining the laminar flame speed of soot forming flames. Our basic assumption is that under the adiabatic condition (in the absence of conductive heat loss), the amount and dynamics of soot formed in the flame is unique for a given fuel/air mixture. The laminar flame speed can be rigorously defined as long as the radiative heat loss can be determined. This laminar flame speed characterizes the flame soot formation and dynamics in addition to the heat release rate. The research involves two integral parts: experiments of spherical and cylindrical sooting flames in microgravity (CWRU), and the computational counterpart (UD) that aims to simulate sooting laminar flames, and the sooting limits of near adiabatic flames. The computations work is described in this report, followed by a summary of the accomplishments achieved to date. Details of the microgra+ experiments will be discussed in a separate, final report prepared by the co-PI, Professor C-J. Sung of CWRU. Here only a brief discussion of these experiments will be given.

Buchanan, Thomas↗
DOE OSTI2015

1.5 nm fabrication of test patterns for characterization of metrological systems

Any metrology tool is only as good as it is calibrated. The characterization of metrology systems requires test patterns at a scale about ten times smaller than the measured features. The fabrication of patterns with linewidths down to 1.5 nm is described. The test sample was designed in such a way that the distribution of linewidths appears to be random at any location. This pseudorandom test pattern is used to characterize dimensional metrology equipment over its entire dynamic range by extracting the modulation transfer function of the system. The test pattern contains alternating lines of silicon and tungsten silicide, each according to its designed width. As a result, the fabricated test samples were imaged using a transmission electron microscope, a scanning electron microscope, and an atomic force microscope. (C) 2015 American Vacuum Society.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1998

Analytical and Experimental Characterization of a Linear-Array Thermopile Scanning Radiometer for Geo-Synchronous Earth Radiation Budget Applications

The Thermal Radiation Group, a laboratory in the department of Mechanical Engineering at Virginia Polytechnic Institute and State University, is currently working towards the development of a new technology for cavity-based radiometers. The radiometer consists of a 256-element linear-array thermopile detector mounted on the wall of a mirrored wedgeshaped cavity. The objective of this research is to provide analytical and experimental characterization of the proposed radiometer. A dynamic end-to-end opto-electrothermal model is developed to simulate the performance of the radiometer. Experimental results for prototype thermopile detectors are included. Also presented is the concept of the discrete Green's function to characterize the optical scattering of radiant energy in the cavity, along with a data-processing algorithm to correct for the scattering. Finally, a parametric study of the sensitivity of the discrete Green's function to uncertainties in the surface properties of the cavity is presented.

Sorensen, Ira J.↗
NASA NTRS1990

Optimal dynamic remapping of data parallel computations

A large class of data parallel computations is characterized by a sequence of phases, with phase changes occurring unpredictably. Dynamic remapping of the workload to processors may be required to maintain good performance. The problem considered, for which the utility of remapping and the future behavior of the workload are uncertain, arises when phases exhibit stable execution requirements during a given phase, but requirements change radically between phases. For these situations, a workload assignment generated for one phase may hinder performance during the next phase. This problem is treated formally for a probabilistic model of computation with at most two phases. The authors address the fundamental problem of balancing the expected remapping performance gain against the delay cost, and they derive the optimal remapping decision policy. The promise of the approach is shown by application to multiprocessor implementations of an adaptive gridding fluid dynamics program and to a battlefield simulation program.

Nicol, David M.↗
DOE OSTI2014

Fisher information due to a phase noisy laser under non-Markovian environment

More recently, K. Berrada [Annals of Physics 340 (2014) 60-69] [1] studied the geometric phase of a two-level atom system driven by a phase noise laser under non-Markovian dynamics in terms of different parameters involved in the whole system, and collapse and revival phenomena were found for large class of states. In this paper, using this noise effect, we study the quantum fisher information (QFI) for a two-level atom system driven by a phase noise laser under non-Markovian dynamics. A new quantity, called QFI flow is used to characterize the damping effect and unveil a fundamental connection between non-Markovian behavior and dynamics of system–environment correlations under phase noise laser. It is shown that QFI flow has disappeared suddenly followed by a sudden birth depending on the kind of the environment damping. QFI flow provides an indicator to characterize the dissipative quantum system’s decoherence by analyzing the behavior of the dynamical non-Markovian coefficients.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2014

Dynamics of soft Nanomaterials captured by transmission electron microscopy in liquid water

In this paper we present in situ transmission electron microscopy (TEM) of soft, synthetic nanoparticles with a comparative analysis using conventional TEM methods. This comparison is made with the simple aim of describing what is an unprecedented example of in situ imaging by TEM. However, we contend the technique will quickly become essential in the characterization of analogous systems, especially where dynamics are of interest in the solvated state. In this case, particles were studied which were obtained from the direct polymerization of an oxaliplatin analog, designed for an ongoing program in novel chemotherapeutic delivery systems. The resulting nanoparticles provided sufficient contrast for facile imaging in situ, and point toward key design parameters that enable this new characterization approach for organic nanomaterials. We describe the preparation of the synthetic micellar nanoparticles to- gether with their characterization in liquid water.

Environmental Molecular Sciences Laboratory↗
DOE OSTI2016

Dynamics of Water in Gemini Surfactant-Based Lyotropic Liquid Crystals

The dynamics of water confined to nanometer-sized domains is important in a variety of applications ranging from proton exchange membranes to crowding effects in biophysics. In this work we study the dynamics of water in gemini surfactant-based lyotropic liquid crystals (LLCs) using molecular dynamics simulations. These systems have well characterized morphologies, e.g., hexagonal, gyroid, and lamellar, and the surfaces of the confining regions can be controlled by modifying the headgroup of the surfactants. This allows one to study the effect of topology, functionalization, and interfacial curvature on the dynamics of confined water. Through analysis of the translational diffusion and rotational relaxation we conclude that the hydration level and resulting confinement lengthscale is the predominate determiner of the rates of water dynamics, and other effects, namely surface functionality and curvature, are largely secondary. In conclusion, this novel analysis of the water dynamics in these LLC systems provides an important comparison for previous studies of water dynamics in lipid bilayers and reverse micelles.

36 MATERIALS SCIENCE↗
DOE OSTI2011

Characterization of amorphous In{sub 2}O{sub 3}: An ab initio molecular dynamics study

In this work, we report on the structural and electronic properties of amorphous In{sub 2}O{sub 3} obtained with ab initio molecular dynamics. Our results show crystal-like short range InO{sub 6} polyhedra having average In-O distance consistent with x-ray spectroscopy data. Structural disorder yields band tailing and localized states, which are responsible of a strong reduction of the electronic gap. Most importantly, the appearance of a peculiar O-O bond imparts n-type character to the amorphous compound and provides contribution for interpreting spectroscopic measurements on indium based oxidized systems. Our findings portray characteristic features to attribute transparent semiconductive properties to amorphous In{sub 2}O{sub 3}.

36 MATERIALS SCIENCE↗