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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on CsSi by Materials Project

SiCs crystallizes in the cubic P-43n space group. The structure is three-dimensional. there are two inequivalent Cs sites. In the first Cs site, Cs is bonded in a 6-coordinate geometry to six Si atoms. There are a spread of Cs–Si bond distances ranging from 3.58–4.03 Å. In the second Cs site, Cs is bonded in a 6-coordinate geometry to six Si atoms. There are three shorter (3.70 Å) and three longer (4.03 Å) Cs–Si bond lengths. There are two inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to six Cs and three equivalent Si atoms. There are two shorter (2.43 Å) and one longer (2.45 Å) Si–Si bond lengths. In the second Si site, Si is bonded in a 9-coordinate geometry to six Cs and three equivalent Si atoms. All Si–Si bond lengths are 2.44 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsSi by Materials Project

SiCs crystallizes in the tetragonal I4_1/acd space group. The structure is three-dimensional. there are two inequivalent Cs sites. In the first Cs site, Cs is bonded in a 8-coordinate geometry to eight equivalent Si atoms. There are a spread of Cs–Si bond distances ranging from 3.75–4.08 Å. In the second Cs site, Cs is bonded in a 6-coordinate geometry to six equivalent Si atoms. There are a spread of Cs–Si bond distances ranging from 3.81–3.99 Å. Si is bonded in a 10-coordinate geometry to seven Cs and three equivalent Si atoms. There are two shorter (2.43 Å) and one longer (2.44 Å) Si–Si bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Multislice forward modeling of coherent surface scattering imaging on surface and interfacial structures

To study nanostructures on substrates, surface-sensitive reflection-geometry scattering techniques such as grazing incident small angle X-ray scattering are commonly used to yield an averaged statistical structural information of the surface sample. Grazing incidence geometry can probe the absolute three-dimensional structural morphology of the sample if a highly coherent beam is used. Coherent surface scattering imaging (CSSI) is a powerful yet non-invasive technique similar to coherent X-ray diffractive imaging (CDI) but performed at small angles and grazing-incidence reflection geometry. A challenge with CSSI is that conventional CDI reconstruction techniques cannot be directly applied to CSSI because the Fourier-transform-based forward models cannot reproduce the dynamical scattering phenomenon near the critical angle of total external reflection of the substrate-supported samples. To overcome this challenge, we have developed a multislice forward model which can successfully simulate the dynamical or multi-beam scattering generated from surface structures and the underlying substrate. The forward model is also demonstrated to be able to reconstruct an elongated 3D pattern from a single shot scattering image in the CSSI geometry through fast-performing CUDA-assisted PyTorch optimization with automatic differentiation.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
NASA NTRS1982

The relationship of motion sickness susceptibility to learned autonomic control for symptom suppression

Twenty-four men were randomly assigned to four equal groups matched in terms of their Coriolis Sickness Susceptibility Index (CSSI). Two groups of subjects were highly susceptible to motion sickness, and two groups were moderately susceptible. All subjects were given six C551 tests at 5-d intervals. Treatment Groups I (highly susceptible) and II (moderately susceptible) were taught to control their autonomic responses, using a training method called autogenic-feedback training (AFT) before the third, fourth, and fifth CSSI tests. Control groups III (highly susceptible) and IV (moderately susceptible) received no treatment. Results showed that both treatment groups significantly improved performance on CSSI tests after training; neither of the control groups changed significantly. Highly and moderately susceptible subjects in the two treatment groups improved at comparable rates. Highly susceptible control group subjects did not habituate across tests as readily as the moderately susceptible controls.

Cowings, P. S.↗
NASA NTRS2023

Numerical Study of Solidification Crack Susceptibility in Novel Refractory Alloy Systems

Calculation of Phase Diagrams (CALPHAD) -based solidification computa­tions, such as Scheil or equilibrium computations, have been utilized to propose crack solidification susceptibility indices (CSSIs) of cracking. These CSSIs have been proposed in order to predict the cracking susceptibility of an alloy in the solidification range, as a function of its solidification frac­tion and as dependent upon its wt.% elemental composition through the CALPHAD computation & via comparative methods between one composition & the next. Recently Kou at al. have proposed a novel CSSI where the gradient of the e.x. Scheil solidification curve is obtained in the critical solidification cracking region of greater than 0.95 fraction of solid. Therefore, a direct Temperature dependent metric is now available for the prediction, and presumably the control, of solidification cracking. In this TM, the researchers apply this Kou gradient method to refractory alloys for the first time & discuss justification for the approach via Spearman rank correlation with Varestraint cracking test data as well as by comparisons with Thermocalc based vulnerability time CSSI calculations. A Python Pycalphad module example of the approach is provided & can be utilized as an open-source resource that utilizes also open-source available thermodynamical databases, making the CSSI quantitative aspect of ICME more available and freely available to practitioners.

ICME integrated computational materials engineerin↗
NASA NTRS1974

Comparison of five levels of motion sickness severity as the basis for grading susceptibility

The motion sickness susceptibility of 275 healthy male subjects was measured quantitatively by a standardized laboratory procedure using a Stille rotational chair. The results, in terms of velocity of the chair and the number of active head movements, were combined into a single numerical score that represented the total stressor stimulus sustained in reaching, in turn, each of five specific criteria for diagnosing the severity of motion sickness. The stressor value (E factor) of a single head movement at each test rpm was adjusted to yield an equivalent susceptibility score (Coriolis Sickness Susceptibility Index, or CSSI) independent of the endpoint selected. Close agreement among the CSSI scores obtained at each endpoint was found in intercorrelations, test-retest reliability coefficients, and frequency distributions, which reflected the orderliness and stability in the appearance, ramification, and intensification of the acute symptomatology evoked in progressing from mild malaise to frank sickness.

Miller, E. F., II↗
NASA NTRS1982

Reducing motion sickness - A comparison of autogenic-feedback training and an alternative cognitive task

Eighteen men were randomly assigned to three groups matched for susceptibility to Coriolis motion sickness. All subjects were given six Coriolis Sickness Susceptibility Index (CSSI) tests separated by 5-d intervals. Treatment Group I subjects were taught to control their own autonomic responses before the third, fourth, and fifth CSSI tests (6 h total training). Group II subjects were given 'sham' training in an alternative cognitive task under conditions otherwise identical to those of Group I. Group III subjects received no treatment. Results showed that Group I subjects could withstand the stress of Coriolis acceleration significantly longer after training. Neither of the other two groups changed significantly.

Toscano, W. B.↗
DOE OSTI2020

Radiation shielding analysis of the small-angle X-ray scattering flight tube end station of APS upgrade project

The CSSI beamline of the APSU will have a 20.5 m long, 2.75 m diameter SS end station designed to accept pink beam. In this work, the radiation shielding analysis of this end station is analyzed using STAC8 and FLUKA codes. Effect of mirror properties such as reflectivity, coating, inclination and roughness as well as variation in the steel composition are also studied. 8 mm thick SS is found to be adequate if the source is defined by a pinhole and the white beam is reflected with two mirrors inclined at 3.0 mradian or more. The dose rates from monochromatic beams are found to be below the desired levels when the XOP calculated bandwidth (BW) are used while the use of a flat 0.1% BW requires the mirror inclinations to be above 2.5 mradian or more. STAC8 results are consistently higher than the FLUKA results by about 1.5–2.0 times.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

Inversion of coherent surface scattering images via deep learning network

Coherent surface scattering imaging is a powerful tool for imaging a surface/interface of a thin nanostructure deposited on an opaque substrate. A mathematical conversion of an object image from a scattering pattern is essential for coherent surface scattering imaging to visualize structures of specimens. It has been achieved by using phase retrieval algorithms requiring oversampling in scattering patterns and employing alternating projection approaches. It is a computationally challenging and time-consuming process. In this paper, we demonstrate CSSI-NN, which is a deep learning neural network model to predict images of objects from scattering intensities in coherent surface scattering imaging. This model allowing for the instant outcome from scattering patterns would be tremendously beneficial not only for effective experiments but also for data analysis of phase retrieval.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1985

What Is Being Done to Control Motion Sickness?

AFT (Autogenic Feedback Training) involves practicing a series of mental exercises to speed up or slow down the control of autonomic activity. This produces a reduced tendency for autonomic activity levels to diverge from baseline (at rest) under stressful motion-sickness-inducing conditions. Subjects conditions. Subjects engaged in applying AFT exercises are required to closely monitor their own bodily sensations during motion-sickness-eliciting tests. These tests include the Coriolis Sickness Susceptibility Index (CSSI), which consists of sitting a subject into a rotating chair that moves at various speeds while a visual background turns at differing speeds and directions, and the Vertical Acceleration Rotation Device (VARD) test, which involves the placing of a subject in a drum that moves in an upward and downward motion until he or she is sick, while simultaneously monitoring the subject's vital signs. These tests provide investigators with evidence of slight changes in autonomic activities such as increases in heart rate, skin temperature, and sweat. All of these symptoms occur in subjects that experience bodily weakness or discomfort with the onset of motion sickness.

Hall, Y. D.↗