Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “HF”

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 865 records · Page 48
All sourcesNASA NTRSDOE OSTI
NASA NTRS2007

Toxicity and Radioprotective Effects of DF-1 and Carbon Nanotubes in Human Lung and Liver Cell Lines

The DF-1 compound, a sixty carbon fullerene derivative, has been shown to have antioxidant effects and is thought to possibly help mediate the effects of radiation on cells. While this is potentially useful, it is important to first understand the effect that the DF-1 has on the cells and the growth rate of the cells to determine if the material itself has any innate toxicity. A growth curve was established for both HF-19 cells, human fibroblasts, and HepG2 cells, liver tissue cells in the presence of two different concentrations of DF-1 and for untreated controls. The cells were plated in triplicate in 60mm dishes and were lifted and counted with a hemocytometer daily for one week. The growth curve data for the HF-19 cells show that while the low concentration of DF-1 had no apparent effect on the growth rate, the high concentration of DF-1 appeared to severely inhibit the growth of the HF-19 cells. The growth curve data for the HepG2 cells shows that the DF-1 compound had no significant effect on the rate at which the cells grew. A second growth curve study was performed plain carbon nanotubes, but with only 24 hour exposure to a high and low concentration of material. The carbon nanotubes are another carbon compound similar to DF-1, but in the shape of a tube, rather than a ball. We hypothesize that nanotubes may also mediate the effect of radiation on cells. This time, nanotubes did not showed any significant effect on the growth rate HF-19 or HepG2 cells. A third growth curve study is underway to further determine the effect of DF-1, nanotubes, and a derivatized nanotube (BHT-nanotubes). This derivatized nanotube has been modified with a compound that is known to be very effective at neutralizing free radicals. We expect that the high concentration of DF-1 and possibly the nanotubes and BHT-nanotubes may inhibit the growth of the HF-19 cells while the low concentration will resemble the growth of the control. We also hypothesize that there will be no significant effect on the growth of the HepG2 cells by the nanotubes, and BHT-nanotubes. In order to examine the usefulness of the DF-1, nanotubes, and BHT-nanotubes in mediating the effects of radiation a clonogenic assay is being performed. The HF-19 cells were plated in different concentrations of the various compounds and exposed to varying amounts of radiation. The cells are being allowed to grow in a small enough concentration so that the ability of each cell to divide can be seen by the development of cell clusters. By comparing the irradiated control to the un-irradiated control the effects of radiation alone can be seen. By comparing the compound treated irradiated cells to the irradiated control the usefulness of each compound can be seen. It is thought that Amifostine, the positive control, will have more regularly dividing cells then the irradiated control, as will DF-1 and hopefully both nanotube materials as well.

Burgoyne, Madeline↗
DOE OSTI2020

Materials Data on HfVGe by Materials Project

HfVGe crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Hf is bonded in a 5-coordinate geometry to four equivalent V and five equivalent Ge atoms. All Hf–V bond lengths are 3.16 Å. There are four shorter (2.73 Å) and one longer (2.82 Å) Hf–Ge bond lengths. V is bonded to four equivalent Hf, four equivalent V, and four equivalent Ge atoms to form a mixture of distorted corner and face-sharing VHf4V4Ge4 cuboctahedra. All V–V bond lengths are 2.63 Å. All V–Ge bond lengths are 2.62 Å. Ge is bonded in a 9-coordinate geometry to five equivalent Hf and four equivalent V atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfSiPt by Materials Project

HfPtSi crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Hf is bonded in a 11-coordinate geometry to six equivalent Pt and five equivalent Si atoms. There are a spread of Hf–Pt bond distances ranging from 2.98–3.11 Å. There are three shorter (2.75 Å) and two longer (2.85 Å) Hf–Si bond lengths. Pt is bonded in a 12-coordinate geometry to six equivalent Hf and four equivalent Si atoms. There are a spread of Pt–Si bond distances ranging from 2.48–2.58 Å. Si is bonded in a 9-coordinate geometry to five equivalent Hf and four equivalent Pt atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfSiPd by Materials Project

HfPdSi crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Hf is bonded in a 11-coordinate geometry to six equivalent Pd and five equivalent Si atoms. There are a spread of Hf–Pd bond distances ranging from 2.99–3.14 Å. There are a spread of Hf–Si bond distances ranging from 2.74–2.83 Å. Pd is bonded in a 12-coordinate geometry to six equivalent Hf, two equivalent Pd, and four equivalent Si atoms. Both Pd–Pd bond lengths are 2.87 Å. There are a spread of Pd–Si bond distances ranging from 2.49–2.59 Å. Si is bonded in a 9-coordinate geometry to five equivalent Hf and four equivalent Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfSnPd by Materials Project

PdHfSn is half-Heusler structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Hf is bonded to four equivalent Pd and six equivalent Sn atoms to form a mixture of distorted corner and face-sharing HfSn6Pd4 tetrahedra. All Hf–Pd bond lengths are 2.76 Å. All Hf–Sn bond lengths are 3.18 Å. Pd is bonded in a body-centered cubic geometry to four equivalent Hf and four equivalent Sn atoms. All Pd–Sn bond lengths are 2.76 Å. Sn is bonded in a 10-coordinate geometry to six equivalent Hf and four equivalent Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfBeSi by Materials Project

BeHfSi crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Be is bonded in a distorted trigonal planar geometry to six equivalent Hf and three equivalent Si atoms. All Be–Hf bond lengths are 2.79 Å. All Be–Si bond lengths are 2.14 Å. Hf is bonded to six equivalent Be and six equivalent Si atoms to form a mixture of edge and face-sharing HfBe6Si6 cuboctahedra. All Hf–Si bond lengths are 2.79 Å. Si is bonded in a distorted trigonal planar geometry to three equivalent Be and six equivalent Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2CS by Materials Project

Hf2SC is H-Phase structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Hf is bonded to three equivalent C and three equivalent S atoms to form a mixture of edge, face, and corner-sharing HfC3S3 octahedra. The corner-sharing octahedra tilt angles range from 0–43°. All Hf–C bond lengths are 2.29 Å. All Hf–S bond lengths are 2.66 Å. C is bonded to six equivalent Hf atoms to form CHf6 octahedra that share corners with six equivalent SHf6 pentagonal pyramids, edges with six equivalent CHf6 octahedra, and edges with six equivalent SHf6 pentagonal pyramids. S is bonded to six equivalent Hf atoms to form distorted SHf6 pentagonal pyramids that share corners with six equivalent CHf6 octahedra, edges with six equivalent CHf6 octahedra, and edges with six equivalent SHf6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 11°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfSiRh by Materials Project

HfRhSi crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Hf is bonded in a 11-coordinate geometry to six equivalent Rh and five equivalent Si atoms. There are a spread of Hf–Rh bond distances ranging from 2.93–3.04 Å. There are three shorter (2.79 Å) and two longer (2.80 Å) Hf–Si bond lengths. Rh is bonded in a 4-coordinate geometry to six equivalent Hf and four equivalent Si atoms. There are a spread of Rh–Si bond distances ranging from 2.44–2.50 Å. Si is bonded in a 9-coordinate geometry to five equivalent Hf and four equivalent Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfSiSe by Materials Project

HfSiSe crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Hf is bonded in a 4-coordinate geometry to four equivalent Si and five equivalent Se atoms. All Hf–Si bond lengths are 2.78 Å. There are four shorter (2.75 Å) and one longer (3.27 Å) Hf–Se bond lengths. Si is bonded in a 8-coordinate geometry to four equivalent Hf and four equivalent Si atoms. All Si–Si bond lengths are 2.54 Å. Se is bonded in a 4-coordinate geometry to five equivalent Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfSiTe by Materials Project

HfSiTe crystallizes in the tetragonal P4/nmm space group. The structure is two-dimensional and consists of one HfSiTe sheet oriented in the (0, 0, 1) direction. Hf is bonded in a 8-coordinate geometry to four equivalent Si and four equivalent Te atoms. All Hf–Si bond lengths are 2.79 Å. All Hf–Te bond lengths are 2.94 Å. Si is bonded in a 8-coordinate geometry to four equivalent Hf and four equivalent Si atoms. All Si–Si bond lengths are 2.59 Å. Te is bonded in a 4-coordinate geometry to four equivalent Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfGeTe by Materials Project

HfGeTe is Matlockite structured and crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Hf is bonded in a 9-coordinate geometry to four equivalent Ge and five equivalent Te atoms. All Hf–Ge bond lengths are 2.87 Å. There are four shorter (2.98 Å) and one longer (3.20 Å) Hf–Te bond lengths. Ge is bonded in a 8-coordinate geometry to four equivalent Hf and four equivalent Ge atoms. All Ge–Ge bond lengths are 2.76 Å. Te is bonded in a 5-coordinate geometry to five equivalent Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfBe5 by Materials Project

Be5Hf crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. there are two inequivalent Be sites. In the first Be site, Be is bonded in a 9-coordinate geometry to six equivalent Be and three equivalent Hf atoms. All Be–Be bond lengths are 2.16 Å. All Be–Hf bond lengths are 2.61 Å. In the second Be site, Be is bonded to eight Be and four equivalent Hf atoms to form a mixture of corner, edge, and face-sharing BeHf4Be8 cuboctahedra. All Be–Be bond lengths are 2.26 Å. All Be–Hf bond lengths are 2.84 Å. Hf is bonded in a 6-coordinate geometry to eighteen Be atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfCo2Sn by Materials Project

HfCo2Sn is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Hf is bonded in a distorted body-centered cubic geometry to eight equivalent Co and six equivalent Sn atoms. All Hf–Co bond lengths are 2.71 Å. All Hf–Sn bond lengths are 3.13 Å. Co is bonded in a distorted body-centered cubic geometry to four equivalent Hf and four equivalent Sn atoms. All Co–Sn bond lengths are 2.71 Å. Sn is bonded in a 8-coordinate geometry to six equivalent Hf and eight equivalent Co atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfSnPt by Materials Project

HfPtSn is half-Heusler structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Hf is bonded in a body-centered cubic geometry to four equivalent Pt and four equivalent Sn atoms. All Hf–Pt bond lengths are 2.82 Å. All Hf–Sn bond lengths are 2.82 Å. Pt is bonded to four equivalent Hf and six equivalent Sn atoms to form distorted PtHf4Sn6 tetrahedra that share corners with four equivalent SnHf4Pt6 tetrahedra, corners with six equivalent PtHf4Sn6 tetrahedra, edges with six equivalent SnHf4Pt6 tetrahedra, and faces with twelve equivalent PtHf4Sn6 tetrahedra. All Pt–Sn bond lengths are 3.26 Å. Sn is bonded to four equivalent Hf and six equivalent Pt atoms to form distorted SnHf4Pt6 tetrahedra that share corners with four equivalent PtHf4Sn6 tetrahedra, corners with six equivalent SnHf4Pt6 tetrahedra, edges with six equivalent PtHf4Sn6 tetrahedra, and faces with twelve equivalent SnHf4Pt6 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2InC by Materials Project

Hf2InC is H-Phase structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Hf is bonded in a 3-coordinate geometry to three equivalent In and three equivalent C atoms. All Hf–In bond lengths are 3.16 Å. All Hf–C bond lengths are 2.27 Å. In is bonded to six equivalent Hf atoms to form distorted InHf6 cuboctahedra that share corners with six equivalent CHf6 octahedra, edges with six equivalent InHf6 cuboctahedra, and edges with six equivalent CHf6 octahedra. The corner-sharing octahedral tilt angles are 20°. C is bonded to six equivalent Hf atoms to form CHf6 octahedra that share corners with six equivalent InHf6 cuboctahedra, edges with six equivalent InHf6 cuboctahedra, and edges with six equivalent CHf6 octahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfSiMo by Materials Project

MoSiHf is delta Molybdenum Boride-derived structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Hf is bonded in a 9-coordinate geometry to four equivalent Mo and five equivalent Si atoms. There are two shorter (2.97 Å) and two longer (3.08 Å) Hf–Mo bond lengths. There are a spread of Hf–Si bond distances ranging from 2.74–2.91 Å. Mo is bonded in a 12-coordinate geometry to four equivalent Hf and four equivalent Si atoms. There are a spread of Mo–Si bond distances ranging from 2.52–2.69 Å. Si is bonded in a 9-coordinate geometry to five equivalent Hf and four equivalent Mo atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfFeP by Materials Project

HfFeP crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Hf is bonded in a 5-coordinate geometry to six equivalent Fe and five equivalent P atoms. There are a spread of Hf–Fe bond distances ranging from 2.78–2.93 Å. There are a spread of Hf–P bond distances ranging from 2.66–2.68 Å. Fe is bonded in a 4-coordinate geometry to six equivalent Hf and four equivalent P atoms. There are a spread of Fe–P bond distances ranging from 2.29–2.42 Å. P is bonded in a 9-coordinate geometry to five equivalent Hf and four equivalent Fe atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfCuSi by Materials Project

HfCuSi crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Hf is bonded in a 11-coordinate geometry to six equivalent Cu and five equivalent Si atoms. There are a spread of Hf–Cu bond distances ranging from 2.83–2.98 Å. There are a spread of Hf–Si bond distances ranging from 2.75–2.80 Å. Cu is bonded in a 10-coordinate geometry to six equivalent Hf and four equivalent Si atoms. There are a spread of Cu–Si bond distances ranging from 2.37–2.52 Å. Si is bonded in a 9-coordinate geometry to five equivalent Hf and four equivalent Cu atoms.

36 MATERIALS SCIENCE↗