SEARCH · Engineering Papers

Results for “linear projection”

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.

SourceResearch connectionFrom yearThrough year

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

At least 847 records · Page 47

All sources NASA NTRS DOE OSTI

NASA NTRS2001

Comparisons of LET distributions measured in low-earth orbit using tissue-equivalent proportional counters and the position-sensitive silicon-detector telescope (RRMD-III)

Determinations of the LET distribution, phi(L), of charged particles within a spacecraft in low-Earth orbit have been made. One method used a cylindrical tissue-equivalent proportional counter (TEPC), with the assumption that for each measured event, lineal energy, y, is equal to LET and thus phi(L) = phi(y). The other was based on the direct measurement of LETs for individual particles using a charged-particle telescope consisting of position-sensitive silicon detectors called RRMD-III. There were differences of up to a factor of 10 between estimates of phi(L) using the two methods on the same mission. This caused estimates of quality factor to vary by a factor of two between the two methods.

Flight Experiment↗

NASA NTRS2005

Biaxial Stress Limit for ULDB Film

The current ULDB design applies stress to the shell film biaxially to control creep in the latitudinal direction. The recent change in design paradigm, from a uniaxial to biaxial stress state basis, arose from a new perspective that the biaxial loading can control strain in both principal surface dimensions as discussed below. The current ULDB project path was thus enabled by a more thorough understanding of the nonlinear viscoelastic properties of the shell film material, linear low-density polyethylene (LLDPE). Although a very similar material is also used in NASA zero-pressure (ZPB) and long-duration balloons (LDB), the different stress state requires a new approach to shell material qualification.

Sterling, W. J.↗

DOE OSTI2021

Ka-band linearizer for the Ultra-Compact X-ray free-electron laser at UCLA

There is a strong demand for accelerating structures able to achieve higher gradients and more compact dimensions for the next generation of linear accelerators for research, industrial and medical applications. Notably innovative technologies will permit compact and affordable advanced accelerators as the linear collider and X-ray free-electron lasers (XFELs) with accelerating gradients over twice the value achieved with current technologies. In particular XFELs are able to produce coherent X-ray pulses with peak brightness 10 orders of magnitude greater than preceding approaches, which has revolutionized numerous research fields through imaging of the nanoscopic world at the time and length scale of atom-based systems, that is of femtosecond and Angstrom. There is a strong interest for combining these two fields, to form a proper tool with the goal of producing a very compact XFEL in order to investigate multi-disciplinary topics in chemistry, biology, materials science, medicine and physics. In the framework of the Ultra-Compact XFEL project under study at the University of California, Los Angeles, a high gradient radio-frequency accelerating structure for the longitudinal phase-space linearization with an integrated voltage of at least 15 MV working on 6th harmonic of the main Linac frequency is required. We here present the electromagnetic design of a cryogenic normal-conducting 8 cm long Ka-band standing-wave linearizer working on π mode with a target accelerating gradient beyond 100 MV/m. The studies have been performed analytically and numerically to investigate the beam dynamics and electromagnetic issues.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2020

Materials Data on CS2NF5 by Materials Project

CNS2F5 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of two pentafluorosulfanyl isothiocyanate molecules. C4+ is bonded in a distorted linear geometry to one N5+ and one S2- atom. The C–N bond length is 1.23 Å. The C–S bond length is 1.55 Å. N5+ is bonded in a bent 120 degrees geometry to one C4+ and one S2- atom. The N–S bond length is 1.69 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in an octahedral geometry to one N5+ and five F1- atoms. There are a spread of S–F bond distances ranging from 1.60–1.62 Å. In the second S2- site, S2- is bonded in a 1-coordinate geometry to one C4+ atom. There are five inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one S2- atom. In the second F1- site, F1- is bonded in a single-bond geometry to one S2- atom. In the third F1- site, F1- is bonded in a single-bond geometry to one S2- atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one S2- atom. In the fifth F1- site, F1- is bonded in a single-bond geometry to one S2- atom.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ag3BO3 by Materials Project

Ag3BO3 crystallizes in the trigonal R-3c space group. The structure is three-dimensional and consists of two Ag3BO3 frameworks. Ag1+ is bonded in a distorted linear geometry to two equivalent O2- atoms. Both Ag–O bond lengths are 2.16 Å. B3+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All B–O bond lengths are 1.39 Å. O2- is bonded in a 3-coordinate geometry to two equivalent Ag1+ and one B3+ atom.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Sr6In2NF by Materials Project

Sr6In2NF is (Cubic) Perovskite-derived structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Sr is bonded in a linear geometry to four equivalent In, one N, and one F atom. All Sr–In bond lengths are 3.77 Å. The Sr–N bond length is 2.56 Å. The Sr–F bond length is 2.76 Å. In is bonded to twelve equivalent Sr atoms to form InSr12 cuboctahedra that share corners with twelve equivalent InSr12 cuboctahedra, faces with six equivalent InSr12 cuboctahedra, faces with four equivalent NSr6 octahedra, and faces with four equivalent FSr6 octahedra. N is bonded to six equivalent Sr atoms to form NSr6 octahedra that share corners with six equivalent FSr6 octahedra and faces with eight equivalent InSr12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. F is bonded to six equivalent Sr atoms to form FSr6 octahedra that share corners with six equivalent NSr6 octahedra and faces with eight equivalent InSr12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ca6In2NF by Materials Project

Ca6In2NF is (Cubic) Perovskite-derived structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ca is bonded in a linear geometry to four equivalent In, one N, and one F atom. All Ca–In bond lengths are 3.52 Å. The Ca–N bond length is 2.39 Å. The Ca–F bond length is 2.59 Å. In is bonded to twelve equivalent Ca atoms to form InCa12 cuboctahedra that share corners with twelve equivalent InCa12 cuboctahedra, faces with six equivalent InCa12 cuboctahedra, faces with four equivalent NCa6 octahedra, and faces with four equivalent FCa6 octahedra. N is bonded to six equivalent Ca atoms to form NCa6 octahedra that share corners with six equivalent FCa6 octahedra and faces with eight equivalent InCa12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. F is bonded to six equivalent Ca atoms to form FCa6 octahedra that share corners with six equivalent NCa6 octahedra and faces with eight equivalent InCa12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ba6Tl2NCl by Materials Project

Ba6Tl2NCl is (Cubic) Perovskite-derived structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ba is bonded in a linear geometry to four equivalent Tl, one N, and one Cl atom. All Ba–Tl bond lengths are 4.15 Å. The Ba–N bond length is 2.73 Å. The Ba–Cl bond length is 3.14 Å. Tl is bonded to twelve equivalent Ba atoms to form TlBa12 cuboctahedra that share corners with twelve equivalent TlBa12 cuboctahedra, faces with six equivalent TlBa12 cuboctahedra, faces with four equivalent NBa6 octahedra, and faces with four equivalent ClBa6 octahedra. N is bonded to six equivalent Ba atoms to form NBa6 octahedra that share corners with six equivalent ClBa6 octahedra and faces with eight equivalent TlBa12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. Cl is bonded to six equivalent Ba atoms to form ClBa6 octahedra that share corners with six equivalent NBa6 octahedra and faces with eight equivalent TlBa12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ca6Sn2NO by Materials Project

Ca6Sn2NO is (Cubic) Perovskite-derived structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ca is bonded in a linear geometry to four equivalent Sn, one N, and one O atom. All Ca–Sn bond lengths are 3.45 Å. The Ca–N bond length is 2.42 Å. The Ca–O bond length is 2.46 Å. Sn is bonded to twelve equivalent Ca atoms to form SnCa12 cuboctahedra that share corners with twelve equivalent SnCa12 cuboctahedra, faces with six equivalent SnCa12 cuboctahedra, faces with four equivalent NCa6 octahedra, and faces with four equivalent OCa6 octahedra. N is bonded to six equivalent Ca atoms to form NCa6 octahedra that share corners with six equivalent OCa6 octahedra and faces with eight equivalent SnCa12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. O is bonded to six equivalent Ca atoms to form OCa6 octahedra that share corners with six equivalent NCa6 octahedra and faces with eight equivalent SnCa12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ba6In2NF by Materials Project

Ba6In2NF is (Cubic) Perovskite-derived structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ba is bonded in a linear geometry to four equivalent In, one N, and one F atom. All Ba–In bond lengths are 3.99 Å. The Ba–N bond length is 2.72 Å. The Ba–F bond length is 2.91 Å. In is bonded to twelve equivalent Ba atoms to form InBa12 cuboctahedra that share corners with twelve equivalent InBa12 cuboctahedra, faces with six equivalent InBa12 cuboctahedra, faces with four equivalent NBa6 octahedra, and faces with four equivalent FBa6 octahedra. N is bonded to six equivalent Ba atoms to form NBa6 octahedra that share corners with six equivalent FBa6 octahedra and faces with eight equivalent InBa12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. F is bonded to six equivalent Ba atoms to form FBa6 octahedra that share corners with six equivalent NBa6 octahedra and faces with eight equivalent InBa12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on FeO2 by Materials Project

FeO2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of four iron dihydroxide molecules. Fe is bonded in a distorted linear geometry to two equivalent O atoms. Both Fe–O bond lengths are 1.32 Å. O is bonded in a single-bond geometry to one Fe atom.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Zn(H3C)2 by Materials Project

Zn(CH3)2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of two dimethylzinc molecules. Zn2+ is bonded in a linear geometry to two equivalent C4- atoms. Both Zn–C bond lengths are 1.94 Å. C4- is bonded to one Zn2+ and three H1+ atoms to form corner-sharing CZnH3 tetrahedra. All C–H bond lengths are 1.10 Å. There are three inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Hg2N by Materials Project

Hg2N is high (beta) Cristobalite structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Hg+1.50+ is bonded in a linear geometry to two equivalent N3- atoms. Both Hg–N bond lengths are 2.23 Å. N3- is bonded to four equivalent Hg+1.50+ atoms to form corner-sharing NHg4 tetrahedra.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Cu23PdN8 by Materials Project

PdCu23N8 is High-temperature superconductor-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Pd is bonded in a linear geometry to two equivalent N atoms. Both Pd–N bond lengths are 2.04 Å. There are fifteen inequivalent Cu sites. In the first Cu site, Cu is bonded in a linear geometry to two N atoms. Both Cu–N bond lengths are 1.90 Å. In the second Cu site, Cu is bonded in a linear geometry to two N atoms. Both Cu–N bond lengths are 1.90 Å. In the third Cu site, Cu is bonded in a linear geometry to two N atoms. Both Cu–N bond lengths are 1.90 Å. In the fourth Cu site, Cu is bonded in a linear geometry to two N atoms. Both Cu–N bond lengths are 1.90 Å. In the fifth Cu site, Cu is bonded in a linear geometry to two N atoms. Both Cu–N bond lengths are 1.90 Å. In the sixth Cu site, Cu is bonded in a linear geometry to two N atoms. Both Cu–N bond lengths are 1.90 Å. In the seventh Cu site, Cu is bonded in a linear geometry to two N atoms. There is one shorter (1.90 Å) and one longer (1.91 Å) Cu–N bond length. In the eighth Cu site, Cu is bonded in a linear geometry to two equivalent N atoms. Both Cu–N bond lengths are 1.93 Å. In the ninth Cu site, Cu is bonded in a linear geometry to two equivalent N atoms. Both Cu–N bond lengths are 1.93 Å. In the tenth Cu site, Cu is bonded in a linear geometry to two equivalent N atoms. Both Cu–N bond lengths are 1.83 Å. In the eleventh Cu site, Cu is bonded in a linear geometry to two N atoms. Both Cu–N bond lengths are 1.90 Å. In the twelfth Cu site, Cu is bonded in a linear geometry to two N atoms. Both Cu–N bond lengths are 1.90 Å. In the thirteenth Cu site, Cu is bonded in a linear geometry to two N atoms. Both Cu–N bond lengths are 1.90 Å. In the fourteenth Cu site, Cu is bonded in a linear geometry to two N atoms. Both Cu–N bond lengths are 1.90 Å. In the fifteenth Cu site, Cu is bonded in a linear geometry to two N atoms. Both Cu–N bond lengths are 1.90 Å. There are three inequivalent N sites. In the first N site, N is bonded to one Pd and five Cu atoms to form corner-sharing NCu5Pd octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the second N site, N is bonded to six Cu atoms to form corner-sharing NCu6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the third N site, N is bonded to six Cu atoms to form corner-sharing NCu6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Cu11PdN4 by Materials Project

PdCu11N4 is High-temperature superconductor-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Pd is bonded in a linear geometry to two equivalent N atoms. Both Pd–N bond lengths are 1.96 Å. There are eight inequivalent Cu sites. In the first Cu site, Cu is bonded in a linear geometry to two equivalent N atoms. Both Cu–N bond lengths are 1.96 Å. In the second Cu site, Cu is bonded in a linear geometry to two N atoms. Both Cu–N bond lengths are 1.90 Å. In the third Cu site, Cu is bonded in a linear geometry to two N atoms. Both Cu–N bond lengths are 1.90 Å. In the fourth Cu site, Cu is bonded in a linear geometry to two N atoms. Both Cu–N bond lengths are 1.90 Å. In the fifth Cu site, Cu is bonded in a linear geometry to two N atoms. Both Cu–N bond lengths are 1.90 Å. In the sixth Cu site, Cu is bonded in a linear geometry to two equivalent N atoms. Both Cu–N bond lengths are 1.96 Å. In the seventh Cu site, Cu is bonded in a linear geometry to two N atoms. There is one shorter (1.90 Å) and one longer (1.91 Å) Cu–N bond length. In the eighth Cu site, Cu is bonded in a linear geometry to two N atoms. There is one shorter (1.90 Å) and one longer (1.91 Å) Cu–N bond length. There are three inequivalent N sites. In the first N site, N is bonded to two equivalent Pd and four Cu atoms to form corner-sharing NCu4Pd2 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second N site, N is bonded to six Cu atoms to form corner-sharing NCu6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the third N site, N is bonded to six Cu atoms to form corner-sharing NCu6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Zn(H3C)2 by Materials Project

Zn(CH3)2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four dimethylzinc molecules. Zn2+ is bonded in a linear geometry to two equivalent C4- atoms. Both Zn–C bond lengths are 1.94 Å. C4- is bonded to one Zn2+ and three H1+ atoms to form corner-sharing CZnH3 tetrahedra. All C–H bond lengths are 1.10 Å. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom. The H–C bond length is 1.10 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom. The H–C bond length is 1.10 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2023

Neural network-based single material beam-hardening correction for X-ray CT in Additive Manufacturing

Beam-hardening (BH) artifacts are ubiquitous in X-ray CT scans of dense metal additively manufactured (AM) parts. While linearization approaches are useful for correcting beam-hardened data from single material objects, they either require a calibration scan or detailed system and material composition information. In this paper, we introduce a neural network-based, material-agnostic method to correct beam-hardening artifacts. We train a neural network to map the acquired beam-hardened projection values and the corresponding estimated thickness of the part based on an initial segmentation to beam-hardening related parameters, which can be used to compute the coefficients of a linearizing correction polynomial. A key strength of our approach is that, once the network is trained, it can be used for correcting beam hardening from a variety of materials without any calibration scans or detailed system and material composition information. Furthermore, our method is robust to errors in the estimated thickness due to the typical challenge of obtaining an accurate initial segmentation from reconstructions impacted by BH artifacts. We demonstrate the utility of our method to obtain high-quality CT reconstructions from a collection of AM parts -- suppressing cupping and streaking artifacts

Rahman, Obaid↗

DOE OSTI2023

An accurate and efficient Ehrenfest dynamics approach for calculating linear and nonlinear electronic spectra

Linear and nonlinear electronic spectra provide an important tool to probe the absorption and transfer of electronic energy. Here, we introduce a pure state Ehrenfest approach to obtain accurate linear and nonlinear spectra that is applicable to systems with large numbers of excited states and complex chemical environments. We achieve this by representing the initial conditions as sums of pure states and unfolding multi-time correlation functions into the Schrödinger picture. By doing this, we show that one can obtain significant improvements in accuracy over the previously used projected Ehrenfest approach and that these benefits are particularly pronounced in cases where the initial condition is a coherence between excited states. While such initial conditions do not arise when calculating linear electronic spectra, they play a vital role in capturing multidimensional spectroscopies. We demonstrate the performance of our method by showing that it is able to quantitatively capture the exact linear, 2D electronic spectroscopy, and pump–probe spectra for a Frenkel exciton model in slow bath regimes and is even able to reproduce the main spectral features in fast bath regimes.

Chemistry↗