Search NASA⌕ Search

SEARCH · Search NASA

Results for “C-Ca”

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.

13 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Evaluation of Stripping Resistance of Organoclay-Modified Asphalt Binder and Aggregate Systems Using an Optical Contact Angle Analyzer

Organoclays, often referred to as nanoclays (NCs), are organically modified phyllosilicates. They are derived from naturally occurring clay minerals and possess unique characteristics in improving the physical and mechanical properties of polymers and rubbers. Recently, NCs have drawn interest in the modification of asphalt binders as micro-scale fillers. A few recent studies have revealed that the addition of NCs in asphalt binders improved binders’ stiffness, aging characteristics, and fatigue resistance. This study aims to evaluate the changes in moisture resistance of different NC-modified asphalt binders through the surface free energy (SFE) technique. This technique estimates SFE properties of binders and aggregates from static contact angle (SCA) data measured from an optical contact angle analyzer (OCA). Further, this study examines the changes in chemical compositions (functional groups) of binders due to the addition of selected NCs by using the Fourier Transformation Infrared (FTIR) technique. To this end, a commonly used performance grade (PG) binder (PG 64-22) modified with four different types (shape and size) of NCs, namely, Cloisite® 15 (C-15), Cloisite® 20 (C-20), Cloisite® Na+ (C-Na), and Cloisite® Ca++ (C-Ca) were evaluated in this study. The SFE data of five different types of aggregates from Oklahoma, namely, Davis Limestone (DL), Snyder Granite (SG), Dolese-Cooperton Limestone (DCL), Hanson-Davis Rhyolite (HDR), and Martin-Marietta-Mill-Creek Granite (MMMG), were used to perform their compatibility with the aforementioned NC-modified binders. The FTIR spectra revealed the presence of various alcohols, ethers, and esters in NC-modified asphalt binders. The moisture susceptibility analysis shows that the addition of NC results in an increase of SFE and cohesive energy of an asphalt binder, which are desired for improved moisture resistance. The addition of NC also shows improved compatibility in cases of all aggregates. Among the five aggregates, MMMCG showed the highest compatibility with all binders, followed by DCL, HDR, DL, and SG. In regard to NCs, the C-15 sample showed the highest compatibility followed by C-20, C-Na, and C-Ca.

Hossain, Zahid↗
NASA NTRS1999

Persistence of bone collagen cross-links in skeletons of the Nuraghi population living in Sardinia 1500-1200 B.C

Bone collagen has a specific molecular ultrastructure which can be proved by birefringence. This protein, forming the main organic component of bone tissue, is known to survive millennia in paleontological bones and teeth. Birefringence of bone collagen obtained from the skeletons of the Nuraghi population living in Sardinia c-ca 1500 years B.C. was found previously by the use of polarizing microscopy [1]. In this paper, using high pressure liquid chromatography (HPLC) techniques, we show the existence of bone collagen cross-links preserved in Nuraghi skeletons after more than 3000 years.

Non-NASA Center↗
DOE OSTI2020

Materials Data on CaC2 by Materials Project

CaC2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ca2+ is bonded to eight equivalent C1- atoms to form distorted edge-sharing CaC8 hexagonal bipyramids. There are a spread of Ca–C bond distances ranging from 2.57–2.83 Å. C1- is bonded in a 5-coordinate geometry to four equivalent Ca2+ and one C1- atom. The C–C bond length is 1.26 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaC2 by Materials Project

CaC2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ca2+ is bonded in a distorted q4 geometry to ten equivalent C1- atoms. There are two shorter (2.57 Å) and eight longer (2.82 Å) Ca–C bond lengths. C1- is bonded in a 2-coordinate geometry to five equivalent Ca2+ and one C1- atom. The C–C bond length is 1.26 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaC2 by Materials Project

CaC2 crystallizes in the cubic Pn-3m space group. The structure is three-dimensional. Ca2+ is bonded to six equivalent C1- atoms to form distorted edge-sharing CaC6 octahedra. All Ca–C bond lengths are 2.48 Å. C1- is bonded in a distorted hexagonal planar geometry to three equivalent Ca2+ and three equivalent C1- atoms. All C–C bond lengths are 1.57 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaC2 by Materials Project

CaC2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to seven C1- atoms. There are a spread of Ca–C bond distances ranging from 2.55–2.83 Å. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to seven C1- atoms. There are a spread of Ca–C bond distances ranging from 2.54–2.84 Å. There are four inequivalent C1- sites. In the first C1- site, C1- is bonded in a 4-coordinate geometry to three Ca2+ and one C1- atom. The C–C bond length is 1.26 Å. In the second C1- site, C1- is bonded in a 4-coordinate geometry to three Ca2+ and one C1- atom. In the third C1- site, C1- is bonded in a 5-coordinate geometry to four Ca2+ and one C1- atom. The C–C bond length is 1.26 Å. In the fourth C1- site, C1- is bonded in a 5-coordinate geometry to four Ca2+ and one C1- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaC2 by Materials Project

CaC2 is Marcasite structured and crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. Ca2+ is bonded to six equivalent C1- atoms to form CaC6 octahedra that share corners with eight equivalent CaC6 octahedra, corners with six equivalent CCa3C tetrahedra, and edges with two equivalent CaC6 octahedra. The corner-sharing octahedral tilt angles are 75°. All Ca–C bond lengths are 2.62 Å. C1- is bonded to three equivalent Ca2+ and one C1- atom to form CCa3C tetrahedra that share corners with three equivalent CaC6 octahedra, corners with thirteen equivalent CCa3C tetrahedra, and an edgeedge with one CCa3C tetrahedra. The corner-sharing octahedra tilt angles range from 64–65°. The C–C bond length is 1.26 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaC2 by Materials Project

CaC2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Ca2+ is bonded in a 9-coordinate geometry to nine C1- atoms. There are a spread of Ca–C bond distances ranging from 2.57–2.95 Å. There are two inequivalent C1- sites. In the first C1- site, C1- is bonded in a 5-coordinate geometry to four equivalent Ca2+ and one C1- atom. The C–C bond length is 1.26 Å. In the second C1- site, C1- is bonded in a 4-coordinate geometry to five equivalent Ca2+ and one C1- atom. The C–C bond length is 1.26 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaC2 by Materials Project

CaC2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Ca2+ is bonded to eight equivalent C1- atoms to form CaC8 hexagonal bipyramids that share corners with eight equivalent CCa4C trigonal bipyramids and edges with twelve equivalent CaC8 hexagonal bipyramids. There are two shorter (2.59 Å) and six longer (2.84 Å) Ca–C bond lengths. C1- is bonded to four equivalent Ca2+ and one C1- atom to form distorted CCa4C trigonal bipyramids that share corners with four equivalent CaC8 hexagonal bipyramids, corners with sixteen equivalent CCa4C trigonal bipyramids, and edges with six equivalent CCa4C trigonal bipyramids. The C–C bond length is 1.27 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaC2 by Materials Project

CaC2 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Ca2+ is bonded to twelve equivalent C1- atoms to form a mixture of distorted edge and face-sharing CaC12 cuboctahedra. All Ca–C bond lengths are 2.64 Å. C1- is bonded in a 3-coordinate geometry to six equivalent Ca2+ and three equivalent C1- atoms. All C–C bond lengths are 1.60 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaC4 by Materials Project

CaC4 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Ca2+ is bonded in a 1-coordinate geometry to sixteen equivalent C+0.50- atoms. All Ca–C bond lengths are 2.75 Å. C+0.50- is bonded in a 7-coordinate geometry to four equivalent Ca2+ and three equivalent C+0.50- atoms. There is one shorter (1.44 Å) and two longer (1.49 Å) C–C bond length.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaC by Materials Project

CaC is Halite, Rock Salt structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ca2+ is bonded to six equivalent C2- atoms to form a mixture of corner and edge-sharing CaC6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Ca–C bond lengths are 2.65 Å. C2- is bonded to six equivalent Ca2+ atoms to form a mixture of corner and edge-sharing CCa6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaC2 by Materials Project

CaC2 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Ca2+ is bonded in a 10-coordinate geometry to ten C1- atoms. There are a spread of Ca–C bond distances ranging from 2.64–2.67 Å. There are two inequivalent C1- sites. In the first C1- site, C1- is bonded in a 8-coordinate geometry to six equivalent Ca2+ and two equivalent C1- atoms. Both C–C bond lengths are 1.55 Å. In the second C1- site, C1- is bonded in a 3-coordinate geometry to four equivalent Ca2+ and three C1- atoms. The C–C bond length is 1.46 Å.

36 MATERIALS SCIENCE↗