Engineering Papers⌕ Search

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.

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

At least 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Mg6Bi2PN by Materials Project

Mg6Bi2PN crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Mg is bonded in a distorted linear geometry to four equivalent Bi, one P, and one N atom. All Mg–Bi bond lengths are 3.31 Å. The Mg–P bond length is 2.52 Å. The Mg–N bond length is 2.15 Å. Bi is bonded to twelve equivalent Mg atoms to form BiMg12 cuboctahedra that share corners with twelve equivalent BiMg12 cuboctahedra, faces with six equivalent BiMg12 cuboctahedra, faces with four equivalent PMg6 octahedra, and faces with four equivalent NMg6 octahedra. P is bonded to six equivalent Mg atoms to form PMg6 octahedra that share corners with six equivalent NMg6 octahedra and faces with eight equivalent BiMg12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. N is bonded to six equivalent Mg atoms to form NMg6 octahedra that share corners with six equivalent PMg6 octahedra and faces with eight equivalent BiMg12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on In2Ni3Se2 by Materials Project

Ni3In2Se2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Ni is bonded in a distorted linear geometry to four In and two equivalent Se atoms. There are two shorter (2.74 Å) and two longer (2.87 Å) Ni–In bond lengths. Both Ni–Se bond lengths are 2.29 Å. There are two inequivalent In sites. In the first In site, In is bonded to six equivalent Ni and six equivalent Se atoms to form InNi6Se6 cuboctahedra that share corners with six equivalent InNi6Se6 cuboctahedra, edges with six equivalent InNi6Se6 cuboctahedra, and faces with six equivalent InNi6Se2 hexagonal bipyramids. All In–Se bond lengths are 3.25 Å. In the second In site, In is bonded to six equivalent Ni and two equivalent Se atoms to form InNi6Se2 hexagonal bipyramids that share corners with six equivalent InNi6Se2 hexagonal bipyramids and faces with six equivalent InNi6Se6 cuboctahedra. Both In–Se bond lengths are 3.14 Å. Se is bonded in a 7-coordinate geometry to three equivalent Ni and four In atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on InCo3SnS2 by Materials Project

Co3SnInS2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Co is bonded in a distorted linear geometry to two equivalent In, two equivalent Sn, and two equivalent S atoms. Both Co–In bond lengths are 2.74 Å. Both Co–Sn bond lengths are 2.66 Å. Both Co–S bond lengths are 2.16 Å. In is bonded to six equivalent Co and six equivalent S atoms to form InCo6S6 cuboctahedra that share corners with six equivalent InCo6S6 cuboctahedra, edges with six equivalent InCo6S6 cuboctahedra, and faces with six equivalent SnCo6S2 hexagonal bipyramids. All In–S bond lengths are 3.16 Å. Sn is bonded to six equivalent Co and two equivalent S atoms to form SnCo6S2 hexagonal bipyramids that share corners with six equivalent SnCo6S2 hexagonal bipyramids and faces with six equivalent InCo6S6 cuboctahedra. Both Sn–S bond lengths are 3.03 Å. S is bonded in a 3-coordinate geometry to three equivalent Co, three equivalent In, and one Sn atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CuN2(Cl2O)2 by Materials Project

CuN2(OCl2)2 crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Cu2+ is bonded in a linear geometry to two equivalent O2- atoms. Both Cu–O bond lengths are 1.82 Å. N3+ is bonded in a rectangular see-saw-like geometry to four equivalent Cl1- atoms. All N–Cl bond lengths are 2.29 Å. O2- is bonded in a distorted single-bond geometry to one Cu2+ and four equivalent Cl1- atoms. There are two shorter (2.13 Å) and two longer (2.46 Å) O–Cl bond lengths. Cl1- is bonded in a 4-coordinate geometry to two equivalent N3+ and two equivalent O2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiCa7(GeH)3 by Materials Project

LiCa7(GeH)3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Li is bonded in a distorted linear geometry to two equivalent Ge and two H atoms. There are one shorter (2.80 Å) and one longer (2.99 Å) Li–Ge bond lengths. There are one shorter (2.11 Å) and one longer (2.13 Å) Li–H bond lengths. There are four inequivalent Ca sites. In the first Ca site, Ca is bonded in a 6-coordinate geometry to four Ge and two H atoms. There are a spread of Ca–Ge bond distances ranging from 2.96–3.55 Å. There are one shorter (2.59 Å) and one longer (2.61 Å) Ca–H bond lengths. In the second Ca site, Ca is bonded in a 6-coordinate geometry to four Ge and two H atoms. There are a spread of Ca–Ge bond distances ranging from 2.93–3.54 Å. There are one shorter (2.62 Å) and one longer (2.65 Å) Ca–H bond lengths. In the third Ca site, Ca is bonded in a 5-coordinate geometry to four Ge and two H atoms. There are a spread of Ca–Ge bond distances ranging from 2.93–3.68 Å. There are one shorter (2.49 Å) and one longer (2.59 Å) Ca–H bond lengths. In the fourth Ca site, Ca is bonded in a 7-coordinate geometry to three Ge and four H atoms. There are two shorter (3.10 Å) and one longer (3.33 Å) Ca–Ge bond lengths. There are a spread of Ca–H bond distances ranging from 2.44–2.57 Å. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 10-coordinate geometry to ten Ca atoms. In the second Ge site, Ge is bonded in a 9-coordinate geometry to two equivalent Li and seven Ca atoms. There are three inequivalent H sites. In the first H site, H is bonded to one Li and five Ca atoms to form a mixture of face and corner-sharing HLiCa5 octahedra. The corner-sharing octahedra tilt angles range from 1–45°. In the second H site, H is bonded to six Ca atoms to form HCa6 octahedra that share corners with four HCa6 octahedra and faces with two HLiCa5 octahedra. The corner-sharing octahedra tilt angles range from 22–45°. In the third H site, H is bonded to one Li and five Ca atoms to form a mixture of distorted face and corner-sharing HLiCa5 octahedra. The corner-sharing octahedra tilt angles range from 1–45°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd(BrO2)2 by Materials Project

Cd(O2Br)2 crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. Cd is bonded in a distorted linear geometry to two equivalent O and four equivalent Br atoms. Both Cd–O bond lengths are 2.16 Å. All Cd–Br bond lengths are 2.97 Å. There are two inequivalent O sites. In the first O site, O is bonded in a distorted single-bond geometry to two equivalent O and one Br atom. Both O–O bond lengths are 1.94 Å. The O–Br bond length is 1.97 Å. In the second O site, O is bonded in a 2-coordinate geometry to one Cd, two equivalent O, and one Br atom. The O–Br bond length is 2.13 Å. Br is bonded in a 2-coordinate geometry to two equivalent Cd and two O atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ga6CuSb7(TeCl3)8 by Materials Project

CuGa6Sb7(TeCl3)8 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Cu1+ is bonded in a linear geometry to two equivalent Cl1- atoms. Both Cu–Cl bond lengths are 2.16 Å. There are three inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded in a tetrahedral geometry to four Cl1- atoms. There are a spread of Ga–Cl bond distances ranging from 2.17–2.29 Å. In the second Ga3+ site, Ga3+ is bonded in a tetrahedral geometry to four Cl1- atoms. There are a spread of Ga–Cl bond distances ranging from 2.19–2.22 Å. In the third Ga3+ site, Ga3+ is bonded in a tetrahedral geometry to four Cl1- atoms. There are a spread of Ga–Cl bond distances ranging from 2.20–2.23 Å. There are four inequivalent Sb3+ sites. In the first Sb3+ site, Sb3+ is bonded in an octahedral geometry to six Te2- atoms. There are a spread of Sb–Te bond distances ranging from 3.05–3.07 Å. In the second Sb3+ site, Sb3+ is bonded in a rectangular see-saw-like geometry to three Te2- and one Cl1- atom. There are one shorter (2.88 Å) and two longer (2.92 Å) Sb–Te bond lengths. The Sb–Cl bond length is 3.20 Å. In the third Sb3+ site, Sb3+ is bonded in a 6-coordinate geometry to three Te2- and three Cl1- atoms. There are a spread of Sb–Te bond distances ranging from 2.89–2.92 Å. There are a spread of Sb–Cl bond distances ranging from 3.25–3.38 Å. In the fourth Sb3+ site, Sb3+ is bonded in a distorted rectangular see-saw-like geometry to three Te2- and one Cl1- atom. There are a spread of Sb–Te bond distances ranging from 2.89–2.95 Å. The Sb–Cl bond length is 3.25 Å. There are four inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 4-coordinate geometry to three Sb3+ and five Cl1- atoms. There are a spread of Te–Cl bond distances ranging from 3.87–4.07 Å. In the second Te2- site, Te2- is bonded in a 8-coordinate geometry to three Sb3+ and five Cl1- atoms. There are a spread of Te–Cl bond distances ranging from 3.82–4.13 Å. In the third Te2- site, Te2- is bonded in a 7-coordinate geometry to three Sb3+ and four Cl1- atoms. There are a spread of Te–Cl bond distances ranging from 3.69–3.99 Å. In the fourth Te2- site, Te2- is bonded in a 9-coordinate geometry to three Sb3+ and six Cl1- atoms. There are a spread of Te–Cl bond distances ranging from 3.61–4.14 Å. There are twelve inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a water-like geometry to one Cu1+ and one Ga3+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Ga3+, one Sb3+, and two Te2- atoms. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Ga3+ and one Te2- atom. In the fourth Cl1- site, Cl1- is bonded in a single-bond geometry to one Ga3+ and two equivalent Te2- atoms. In the fifth Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Ga3+, one Sb3+, and three Te2- atoms. In the sixth Cl1- site, Cl1- is bonded in a single-bond geometry to one Ga3+, one Sb3+, and three Te2- atoms. In the seventh Cl1- site, Cl1- is bonded in a single-bond geometry to one Ga3+ and one Te2- atom. In the eighth Cl1- site, Cl1- is bonded in a single-bond geometry to one Ga3+ and one Te2- atom. In the ninth Cl1- site, Cl1- is bonded in a single-bond geometry to one Ga3+, one Sb3+, and two Te2- atoms. In the tenth Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Ga3+, one Sb3+, and one Te2- atom. In the eleventh Cl1- site, Cl1- is bonded in a single-bond geometry to one Ga3+ and two equivalent Te2- atoms. In the twelfth Cl1- site, Cl1- is bonded in a single-bond geometry to one Ga3+ and two equivalent Te2- atoms.

36 MATERIALS SCIENCE↗
NASA NTRS1993

Rapid exploration of curvilinear grids using direct volume rendering

Fast techniques for direct volume rendering over curvilinear grids of hexahedral cells are developed. This type of 3D grid is common in computational fluid dynamics and finite element analysis. Four new projection methods are presented and compared with each other and with previous methods for tetrahedral grids and rectilinear grids. All four methods use polygon-rendering hardware for speed. A simplified algorithm for visibility ordering, which is based on a combination of breadth-first and depth-first searches, is described. A new multi-pass blending method is described that reduces visual artifacts that are introduced by linear interpolation in hardware where exponential interpolation is needed. Multi-pass blending is of equal interest to hardware-oriented projection methods used on rectilinear grids. Visualization tools that permit rapid data banding and cycling through transfer functions, as well as region restrictions, are described.

Vangelder, Allen↗
DOE OSTI2022

Exploiting non-linear scales in galaxy–galaxy lensing and galaxy clustering: A forecast for the dark energy survey

ABSTRACT The combination of galaxy–galaxy lensing (GGL) and galaxy clustering is a powerful probe of low-redshift matter clustering, especially if it is extended to the non-linear regime. To this end, we use an N-body and halo occupation distribution (HOD) emulator method to model the redMaGiC sample of colour-selected passive galaxies in the Dark Energy Survey (DES), adding parameters that describe central galaxy incompleteness, galaxy assembly bias, and a scale-independent multiplicative lensing bias Alens. We use this emulator to forecast cosmological constraints attainable from the GGL surface density profile ΔΣ(rp) and the projected galaxy correlation function wp, gg(rp) in the final (Year 6) DES data set over scales $r_p=0.3\!-\!30.0\, h^{-1} \, \mathrm{Mpc}$. For a $3{{\ \rm per\ cent}}$ prior on Alens we forecast precisions of $1.9{{\ \rm per\ cent}}$, $2.0{{\ \rm per\ cent}}$, and $1.9{{\ \rm per\ cent}}$ on Ωm, σ8, and $S_8 \equiv \sigma _8\Omega _m^{0.5}$, marginalized over all halo occupation distribution (HOD) parameters as well as Alens. Adding scales $r_p=0.3\!-\!3.0\, h^{-1} \, \mathrm{Mpc}$ improves the S8 precision by a factor of ∼1.6 relative to a large scale ($3.0\!-\!30.0\, h^{-1} \, \mathrm{Mpc}$) analysis, equivalent to increasing the survey area by a factor of ∼2.6. Sharpening the Alens prior to $1{{\ \rm per\ cent}}$ further improves the S8 precision to $1.1{{\ \rm per\ cent}}$, and it amplifies the gain from including non-linear scales. Our emulator achieves per cent-level accuracy similar to the projected DES statistical uncertainties, demonstrating the feasibility of a fully non-linear analysis. Obtaining precise parameter constraints from multiple galaxy types and from measurements that span linear and non-linear clustering offers many opportunities for internal cross-checks, which can diagnose systematics and demonstrate the robustness of cosmological results.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

An integrated process for butanol production from cellulosic biomass and CO 2 using engineered clostridia in a linear immobilized bioreactor

Engineered platforms using mixed microbial consortia to consolidate multiple reaction steps and perform disparate conversions simultaneously can substantially enhance the carbon efficiency of biomass conversion processes and lower the biofuel cost to an economically competitive level. In this project, an integrated process will be developed to produce n-butanol from cellulosic biomass and waste gas streams using two engineered clostridial strains, one butanol-tolerant solventogenic strain and one carboxydotrophic acetogen, co-immobilized in a “Linear Immobilized Bioreactor” (LIBR). The CO 2 and H 2 produced by the solventogenic strain will be used by the carboxydotrophic strain to produce acetate (and butyrate) that in turns can be used by the solventogenic strain to produce more butanol. Such a co-cultured fermentation has the potential to increase butanol production from biomass hydrolysate sugars by up to 50% with 100% reduction in CO 2 emission. Butanol produced in the fermentation will be stripped by the rising bubbles of fermentation produced gases (CO 2 and H 2 ) in the LIBR and separated via a condenser, alleviating butanol inhibition while achieving continuous butanol production at a high productivity and product titer, which can reduce both water and energy consumptions by over 50% compared to conventional ethanol and ABE fermentation processes. Phase I study proved the new bioprocess concept and verified our hypothesis that the proposed LIBR and co-cultured fermentation can enhance the conversion of lignocellulosic sugars to butanol with higher butanol yield, productivity and titer, leading to reduced biobutanol cost to compete more favorably with bioethanol and fossil fuels. A prototype lab-scale LIBR for multiphase fermentation was constructed to investigate and demonstrate the technical feasibility and advantages of the LIBR for multiphase fermentation involving sugars and gaseous substrates. The LIBR will be optimized and evaluated for its economic feasibility for biobutanol production from lignocellulosic biomass and industrial waste gases in Phase II.

09 BIOMASS FUELS↗
NASA NTRS2009

Sensitivity Analysis of Linear Programming and Quadratic Programming Algorithms for Control Allocation

The Next Generation (NextGen) transport aircraft configurations being investigated as part of the NASA Aeronautics Subsonic Fixed Wing Project have more control surfaces, or control effectors, than existing transport aircraft configurations. Conventional flight control is achieved through two symmetric elevators, two antisymmetric ailerons, and a rudder. The five effectors, reduced to three command variables, produce moments along the three main axes of the aircraft and enable the pilot to control the attitude and flight path of the aircraft. The NextGen aircraft will have additional redundant control effectors to control the three moments, creating a situation where the aircraft is over-actuated and where a simple relationship does not exist anymore between the required effector deflections and the desired moments. NextGen flight controllers will incorporate control allocation algorithms to determine the optimal effector commands and attain the desired moments, taking into account the effector limits. Approaches to solving the problem using linear programming and quadratic programming algorithms have been proposed and tested. It is of great interest to understand their relative advantages and disadvantages and how design parameters may affect their properties. In this paper, we investigate the sensitivity of the effector commands with respect to the desired moments and show on some examples that the solutions provided using the l2 norm of quadratic programming are less sensitive than those using the l1 norm of linear programming.

Frost, Susan A.↗
DOE OSTI2020

Materials Data on NaFe7(PO4)6 by Materials Project

NaFe7(PO4)6 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Na1+ is bonded in a distorted linear geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.79–3.11 Å. There are four inequivalent Fe+2.43+ sites. In the first Fe+2.43+ site, Fe+2.43+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Fe–O bond distances ranging from 1.89–2.12 Å. In the second Fe+2.43+ site, Fe+2.43+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with two PO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.88–1.99 Å. In the third Fe+2.43+ site, Fe+2.43+ is bonded to four O2- atoms to form distorted FeO4 trigonal pyramids that share corners with two PO4 tetrahedra and an edgeedge with one FeO4 trigonal pyramid. There are a spread of Fe–O bond distances ranging from 1.92–2.14 Å. In the fourth Fe+2.43+ site, Fe+2.43+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (1.95 Å) and two longer (2.23 Å) Fe–O bond lengths. There are three inequivalent P5+ sites. In the first P5+ site, P5+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are a spread of P–O bond distances ranging from 1.58–1.76 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one FeO4 tetrahedra and a cornercorner with one FeO4 trigonal pyramid. There are a spread of P–O bond distances ranging from 1.53–1.60 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one FeO4 tetrahedra and a cornercorner with one FeO4 trigonal pyramid. There are a spread of P–O bond distances ranging from 1.53–1.56 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one Fe+2.43+, and one P5+ atom. In the third O2- site, O2- is bonded in a trigonal non-coplanar geometry to two equivalent Fe+2.43+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one Fe+2.43+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe+2.43+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two Fe+2.43+ and one O2- atom. The O–O bond length is 1.52 Å. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe+2.43+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to two Fe+2.43+ and one O2- atom. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe+2.43+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe+2.43+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe+2.43+ and one P5+ atom. In the twelfth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, two Fe+2.43+, and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KLi7(H2N)8 by Materials Project

KLi7(NH2)8 crystallizes in the tetragonal I4_1/a space group. The structure is three-dimensional. K1+ is bonded in a distorted linear geometry to two equivalent H1+ atoms. Both K–H bond lengths are 2.29 Å. There are six inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a 4-coordinate geometry to four N3- and four H1+ atoms. There are two shorter (2.21 Å) and two longer (2.22 Å) Li–N bond lengths. There are two shorter (2.29 Å) and two longer (2.30 Å) Li–H bond lengths. In the second Li1+ site, Li1+ is bonded in a 2-coordinate geometry to four N3- and four H1+ atoms. There are two shorter (2.11 Å) and two longer (2.21 Å) Li–N bond lengths. There are two shorter (2.16 Å) and two longer (2.26 Å) Li–H bond lengths. In the third Li1+ site, Li1+ is bonded in a tetrahedral geometry to four N3- atoms. There are two shorter (2.10 Å) and two longer (2.12 Å) Li–N bond lengths. In the fourth Li1+ site, Li1+ is bonded in a tetrahedral geometry to four N3- atoms. There are two shorter (2.11 Å) and two longer (2.20 Å) Li–N bond lengths. In the fifth Li1+ site, Li1+ is bonded in a 4-coordinate geometry to four N3- and two equivalent H1+ atoms. There are two shorter (2.16 Å) and two longer (2.27 Å) Li–N bond lengths. Both Li–H bond lengths are 2.27 Å. In the sixth Li1+ site, Li1+ is bonded in a 4-coordinate geometry to three N3- and one H1+ atom. There are a spread of Li–N bond distances ranging from 2.01–2.09 Å. The Li–H bond length is 1.92 Å. There are four inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted water-like geometry to four Li1+ and two H1+ atoms. Both N–H bond lengths are 1.03 Å. In the second N3- site, N3- is bonded in a distorted water-like geometry to three Li1+ and two H1+ atoms. Both N–H bond lengths are 1.03 Å. In the third N3- site, N3- is bonded in a distorted water-like geometry to four Li1+ and two H1+ atoms. Both N–H bond lengths are 1.03 Å. In the fourth N3- site, N3- is bonded in a distorted water-like geometry to two Li1+ and two H1+ atoms. Both N–H bond lengths are 1.03 Å. There are eight inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one Li1+ and one N3- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one Li1+ and one N3- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one Li1+ and one N3- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one Li1+ and one N3- atom. In the fifth H1+ site, H1+ is bonded in a distorted single-bond geometry to one K1+, two Li1+, and one N3- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiMo6(SeS3)2 by Materials Project

LiMo6(SeS3)2 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Li1+ is bonded in a distorted linear geometry to two equivalent Se2- and six equivalent S2- atoms. Both Li–Se bond lengths are 2.43 Å. All Li–S bond lengths are 3.21 Å. Mo+2.50+ is bonded to one Se2- and four equivalent S2- atoms to form a mixture of edge and corner-sharing MoSeS4 square pyramids. The Mo–Se bond length is 2.54 Å. There are a spread of Mo–S bond distances ranging from 2.44–2.50 Å. Se2- is bonded in a 1-coordinate geometry to one Li1+ and three equivalent Mo+2.50+ atoms. S2- is bonded in a 5-coordinate geometry to one Li1+ and four equivalent Mo+2.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2026

A projection method for particle resampling

Particle discretizations of partial differential equations are advantageous for high-dimensional kinetic models in phase-space due to their better scalability than continuum approaches with respect to dimension. Complex processes collectively referred to as particle noise hamper long time simulations with particle methods. One approach to address this problem is particle mesh adaptivity, or remapping, known as particle resampling and remeshing. Here, this work introduces a resampling method that projects particles to and from a (finite element) function space. The method is simple, using standard sparse linear algebra and finite element techniques, and it preserves all moments up to the order of a polynomial represented exactly by the continuum function space. It is distinguished from most other mesh-based methods in that new particle positions and number are decoupled from the mesh, allowing particle and continuum meshes to be adapted relatively independently. While this work is developed with structured particle and continuum phase-space grids on 1X + 1V Vlasov-Poisson models of Landau damping and two-stream instability, the method is well-suited to unstructured grids. Stable long time dynamics are demonstrated up to time T = 500. Reproducibility artifacts and data are publicly available.

Kinetic methods↗
DOE OSTI2020

The Architecture of Metabolism Maximizes Biosynthetic Diversity in the Largest Class of Fungi

Abstract Ecological diversity in fungi is largely defined by metabolic traits, including the ability to produce secondary or “specialized” metabolites (SMs) that mediate interactions with other organisms. Fungal SM pathways are frequently encoded in biosynthetic gene clusters (BGCs), which facilitate the identification and characterization of metabolic pathways. Variation in BGC composition reflects the diversity of their SM products. Recent studies have documented surprising diversity of BGC repertoires among isolates of the same fungal species, yet little is known about how this population-level variation is inherited across macroevolutionary timescales. Here, we applied a novel linkage-based algorithm to reveal previously unexplored dimensions of diversity in BGC composition, distribution, and repertoire across 101 species of Dothideomycetes, which are considered the most phylogenetically diverse class of fungi and known to produce many SMs. We predicted both complementary and overlapping sets of clustered genes compared with existing methods and identified novel gene pairs that associate with known secondary metabolite genes. We found that variation among sets of BGCs in individual genomes is due to nonoverlapping BGC combinations and that several BGCs have biased ecological distributions, consistent with niche-specific selection. We observed that total BGC diversity scales linearly with increasing repertoire size, suggesting that secondary metabolites have little structural redundancy in individual fungi. We project that there is substantial unsampled BGC diversity across specific families of Dothideomycetes, which will provide a roadmap for future sampling efforts. Our approach and findings lend new insight into how BGC diversity is generated and maintained across an entire fungal taxonomic class.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Maximizing the efficiency of plasma-based lepton accelerators

The next generation of particle accelerators will likely rely on compact accelerating structures to achieve very high gradients; one such candidate is accelerators using plasmas for the accelerating structures. Because of the small length scales of these structures, they can also be prone to the beam break-up instability, which would spoil the quality of the beam and leave it unsuitable for many applications. The goal of this project is to develop a framework for understanding the instabilities in plasma accelerators using language from conventional linear accelerator instabilities, such as wake fields and wake functions. During the course of this Phase I, we benchmarked a pseudo-spectral particle-in-cell code to determine its suitability for computing wake functions, and developed a procedure for extracting wake functions from a sequence of simulations using this code.

43 PARTICLE ACCELERATORS↗
DOE OSTI2025

A Measurement of Atmospheric Circular Polarization with POLARBEAR

At millimeter wavelengths, the atmospheric emission is circularly polarized owing to the Zeeman splitting of molecular oxygen by the Earth's magnetic field. We report a measurement of the signal in the 150 GHz band using 3 yr of observational data with the POLARBEAR project. Nonidealities of a continuously rotating half-wave plate (HWP) partially convert circularly polarized light to linearly polarized light. While POLARBEAR detectors are sensitive to linear polarization, this effect makes them sensitive to circular polarization. Although this was not the intended use, we utilized this conversion to measure circular polarization. We reconstruct the azimuthal gradient of the circular polarization signal and measure its dependency from the scanning direction and the detector bandpass. We compare the signal with a simulation based on atmospheric emission theory, the detector bandpass, and the HWP leakage spectrum model. We find the ratio of the observed azimuthal slope to the simulated slope is 0.92 ± 0.01(stat) ± 0.07(sys). This ratio corresponds to a brightness temperature of 3.8 mK at the effective band center of 121.8 GHz and bandwidth of 3.5 GHz estimated from representative detector bandpass and the spectrum of Zeeman emission. This result validates our understanding of the instrument and reinforces the feasibility of measuring the circular polarization using the imperfection of continuously rotating HWP. Continuously rotating HWP is popular in ongoing and future cosmic microwave background experiments to modulate the polarized signal. This work shows a method for signal extraction and leakage subtraction that can help measure circular polarization in such experiments.

79 ASTRONOMY AND ASTROPHYSICS↗