SEARCH · Engineering Papers
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.
SmPt3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Sm2+ is bonded to twelve equivalent Pt+0.67- atoms to form a mixture of corner and face-sharing SmPt12 cuboctahedra. All Sm–Pt bond lengths are 2.95 Å. Pt+0.67- is bonded in a distorted square co-planar geometry to four equivalent Sm2+ atoms.
Pt3Zr is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Zr2+ is bonded to twelve equivalent Pt+0.67- atoms to form a mixture of face and corner-sharing ZrPt12 cuboctahedra. All Zr–Pt bond lengths are 2.87 Å. Pt+0.67- is bonded in a distorted square co-planar geometry to four equivalent Zr2+ atoms.
Pt3Sc is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Sc2+ is bonded to twelve equivalent Pt+0.67- atoms to form a mixture of face and corner-sharing ScPt12 cuboctahedra. All Sc–Pt bond lengths are 2.84 Å. Pt+0.67- is bonded in a distorted square co-planar geometry to four equivalent Sc2+ atoms.
NdPt3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Nd2+ is bonded to twelve equivalent Pt+0.67- atoms to form a mixture of face and corner-sharing NdPt12 cuboctahedra. All Nd–Pt bond lengths are 2.98 Å. Pt+0.67- is bonded in a distorted square co-planar geometry to four equivalent Nd2+ atoms.
Cu3BiSe2O8I crystallizes in the orthorhombic Pmmn space group. The structure is three-dimensional. there are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded in a square co-planar geometry to four O2- and two equivalent I1- atoms. There is two shorter (1.98 Å) and two longer (1.99 Å) Cu–O bond length. Both Cu–I bond lengths are 3.24 Å. In the second Cu2+ site, Cu2+ is bonded in a square co-planar geometry to four O2- and two equivalent I1- atoms. There is two shorter (1.97 Å) and two longer (2.00 Å) Cu–O bond length. Both Cu–I bond lengths are 3.20 Å. Bi3+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Bi–O bond distances ranging from 2.29–2.93 Å. Se4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is one shorter (1.72 Å) and two longer (1.75 Å) Se–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Cu2+, one Bi3+, and one Se4+ atom. In the second O2- site, O2- is bonded to three Cu2+ and one Bi3+ atom to form a mixture of corner and edge-sharing OCu3Bi tetrahedra. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cu2+, one Bi3+, and one Se4+ atom. I1- is bonded in a distorted hexagonal planar geometry to six Cu2+ atoms.
Nd2O3 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Nd3+ is bonded to six equivalent O2- atoms to form a mixture of distorted face, edge, and corner-sharing NdO6 pentagonal pyramids. All Nd–O bond lengths are 2.41 Å. O2- is bonded in a square co-planar geometry to four equivalent Nd3+ atoms.
PaSi3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Pa4+ is bonded to twelve equivalent Si+1.33- atoms to form a mixture of face and corner-sharing PaSi12 cuboctahedra. All Pa–Si bond lengths are 2.91 Å. Si+1.33- is bonded in a distorted square co-planar geometry to four equivalent Pa4+ atoms.
HfOs3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Hf4+ is bonded to twelve equivalent Os+1.33- atoms to form a mixture of corner and face-sharing HfOs12 cuboctahedra. All Hf–Os bond lengths are 2.81 Å. Os+1.33- is bonded in a distorted square co-planar geometry to four equivalent Hf4+ atoms.
ZrOs3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Zr4+ is bonded to twelve equivalent Os+1.33- atoms to form a mixture of face and corner-sharing ZrOs12 cuboctahedra. All Zr–Os bond lengths are 2.83 Å. Os+1.33- is bonded in a distorted square co-planar geometry to four equivalent Zr4+ atoms.
IrS2 is pyrite-like structured and crystallizes in the cubic Pa-3 space group. The structure is three-dimensional. Ir4+ is bonded to six equivalent S2- atoms to form corner-sharing IrS6 octahedra. The corner-sharing octahedral tilt angles are 62°. All Ir–S bond lengths are 2.37 Å. S2- is bonded in a distorted trigonal planar geometry to three equivalent Ir4+ atoms.
Li6V3Mn(PO4)6 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are seven inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Li–O bond distances ranging from 2.21–2.35 Å. In the second Li1+ site, Li1+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Li–O bond distances ranging from 2.23–2.40 Å. In the third Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.16–2.49 Å. In the fourth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.09–2.53 Å. In the fifth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.15–2.44 Å. In the sixth Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.13–2.50 Å. In the seventh Li1+ site, Li1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Li–O bond distances ranging from 2.12–2.52 Å. There are three inequivalent V+3.33+ sites. In the first V+3.33+ site, V+3.33+ is bonded to six O2- atoms to form VO6 octahedra that share corners with six PO4 tetrahedra and an edgeedge with one MnO6 octahedra. There are a spread of V–O bond distances ranging from 1.98–2.17 Å. In the second V+3.33+ site, V+3.33+ is bonded to six O2- atoms to form VO6 octahedra that share corners with six PO4 tetrahedra and an edgeedge with one VO6 octahedra. There are a spread of V–O bond distances ranging from 1.97–2.13 Å. In the third V+3.33+ site, V+3.33+ is bonded to six O2- atoms to form VO6 octahedra that share corners with six PO4 tetrahedra and an edgeedge with one VO6 octahedra. There are a spread of V–O bond distances ranging from 1.95–2.16 Å. Mn2+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with six PO4 tetrahedra and an edgeedge with one VO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.95–2.31 Å. There are six inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one MnO6 octahedra and corners with three VO6 octahedra. The corner-sharing octahedra tilt angles range from 53–55°. There is one shorter (1.55 Å) and three longer (1.56 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra and corners with two equivalent MnO6 octahedra. The corner-sharing octahedra tilt angles range from 37–61°. There is one shorter (1.52 Å) and three longer (1.57 Å) P–O bond length. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four VO6 octahedra. The corner-sharing octahedra tilt angles range from 41–59°. There are a spread of P–O bond distances ranging from 1.52–1.59 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one MnO6 octahedra and corners with three VO6 octahedra. The corner-sharing octahedra tilt angles range from 52–56°. There is two shorter (1.55 Å) and two longer (1.56 Å) P–O bond length. In the fifth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one MnO6 octahedra and corners with three VO6 octahedra. The corner-sharing octahedra tilt angles range from 43–58°. There are a spread of P–O bond distances ranging from 1.52–1.60 Å. In the sixth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one MnO6 octahedra and corners with three VO6 octahedra. The corner-sharing octahedra tilt angles range from 42–58°. There are a spread of P–O bond distances ranging from 1.52–1.58 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V+3.33+, and one P5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one V+3.33+, one Mn2+, and one P5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Li1+, one V+3.33+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Li1+, one Mn2+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Li1+, one Mn2+, and one P5+ atom. In the sixth O2- site, O2- is bonded to two Li1+, one V+3.33+, and one P5+ atom to form distorted OLi2VP trigonal pyramids that share corners with two equivalent OLi2VP trigonal pyramids and an edgeedge with one OLi2MnP trigonal pyramid. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one V+3.33+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Li1+, one V+3.33+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one V+3.33+, one Mn2+, and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Li1+, one V+3.33+, and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Li1+, one V+3.33+, and one P5+ atom. In the twelfth O2- site, O2- is bonded to two Li1+, one Mn2+, and one P5+ atom to form a mixture of distorted edge and corner-sharing OLi2MnP trigonal pyramids. In the thirteenth O2- site, O2- is bonded in a 4-coordinate geometry to three Li1+ and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent V+3.33+ and one P5+ atom. In the fifteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Li1+, one V+3.33+, and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one V+3.33+, and one P5+ atom. In the seventeenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Mn2+, and one P5+ atom. In the eighteenth O2- site, O2- is bonded in a 4-coordinate geometry to three Li1+ and one P5+ atom. In the nineteenth O2- site, O2- is bonded to two equivalent Li1+, one V+3.33+, and one P5+ atom to form a mixture of distorted edge and corner-sharing OLi2VP trigonal pyramids. In the twentieth O2- site, O2- is bonded in a 4-coordinate geometry to three Li1+ and one P5+ atom. In the twenty-first O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent V+3.33+ and one P5+ atom. In the twenty-second O2- site, O2- is bonded in a 4-coordinate geometry to three Li1+ and one P5+ atom. In the twenty-third O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V+3.33+, and one P5+ atom. In the twenty-fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one V+3.33+, and one P5+ atom.
RbK2Pt crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Rb is bonded in a square co-planar geometry to four Pt atoms. All Rb–Pt bond lengths are 3.84 Å. K is bonded in a water-like geometry to two equivalent Pt atoms. Both K–Pt bond lengths are 3.33 Å. There are two inequivalent Pt sites. In the first Pt site, Pt is bonded in a distorted body-centered cubic geometry to four equivalent Rb and four equivalent K atoms. All Pt–K bond lengths are 3.33 Å. In the second Pt site, Pt is bonded in a distorted body-centered cubic geometry to four equivalent Rb and four equivalent K atoms.
NiTe2 is pyrite-like structured and crystallizes in the cubic Pa-3 space group. The structure is three-dimensional. Ni4+ is bonded to six equivalent Te2- atoms to form corner-sharing NiTe6 octahedra. The corner-sharing octahedral tilt angles are 61°. All Ni–Te bond lengths are 2.63 Å. Te2- is bonded in a distorted trigonal planar geometry to three equivalent Ni4+ atoms.
Investigation of the effect of using plane quadrilateral membrane elements for modeling nonplanar structures. The effect is assessed by analyzing a simplified finite element model with the aid of the structure network analysis program. The results obtained indicate that the use of planar quadrilateral membrane elements for modeling bending problems can lead to large errors if the four points that define the quadrilateral are not in the same plane.
Antenna for imaging of polar regions has terrestrial applications. Antenna consists of four horizontally-polarized 19.0 by 0.6-m planar waveguide arrays and appropriate feed networks mounted on single aluminum supporting structure. Antenna suitable for high quality imaging of sea ice in polar regions above 60 degrees latitude.
A numerical simulation of bubble-type vortex breakdown using a unique discrete form of the full 3-D, unsteady incompressible Navier-Stokes equations was performed. The Navier-Stokes equations were written in a vorticity-velocity form and the physical problem was not restricted to axisymmetric flow. The problem was parametized on a Rossby- Reynolds-number basis. Utilization of this parameter duo was shown to dictate the form of the free-field boundary condition specification and allowed control of axial breakdown location within the computational domain. The structure of the breakdown bubble was studied through time evolution plots of planar projected velocity vectors as well as through plots of particle traces and vortex lines. These results compared favorably with previous experimental studies. In addition, profiles of all three velocity components are presented at various axial stations and a Fourier analysis was performed to identify the dominant circumferential modes. The dynamics of the breakdown process were studied through plots of axial variation of rate of change of integrated total energy and rate of change of integrated enstrophy, as well as through contour plots of velocity, vorticity and pressure.
A design is presented for a semi-integrated millimeter/submillimeter wavelength receiver/transmitter front end incorporating a planar antenna and a solid-state device in an efficient feed structure which can be matched directly to high f-number optical systems. The feed system combines the simplicity and robustness of a dielectric substrate lens with the high gain of a parabolic reflector in a single structure that is termed a dielectric-filled parabola. The same fundamental unit can be configured as either a heterodyne or direct detection mode receiver, a power transmitter or a frequency multiplier by changing out the solid-state device and/or the integrated antenna. The structure can also be used with a small integrated antenna array in a multibeam or imaging arrangement. Design and fabrication details for the feed system are given. These are followed by beam pattern and impedance measurements taken on a microwave model when dipole, bow-tie, log-periodic, and log-spiral antennas are used as the integrated feed elements.
Planar laser-induced fluorescence (PLIF) is used to visualize the flame structure via OH, NO, and fuel imaging in kerosene- burning gas turbine combustor flame tubes. When compared to simple gaseous hydrocarbon flames and hydrogen flames, flame tube testing complexities include spectral interferences from large fuel fragments, unknown turbulence interactions, high pressure operation, and the concomitant need for windows and remote operation. Complications of these and other factors as they apply to image analysis are considered. Because both OH and gas turbine engine fuels (commercial and military) can be excited and detected using OH transition lines, a narrowband and a broadband detection scheme are compared and the benefits and drawbacks of each method are examined.