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At least 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on ErFeC6(N3O2)2 by Materials Project

FeEr(CN)6(O2)2 crystallizes in the monoclinic P2_1/m space group. The structure is zero-dimensional and consists of two 1,2,3,4-tetraoxacyclobutane molecules; two iron molecules; and two Er(CN)6 clusters. In each Er(CN)6 cluster, Er3+ is bonded in a distorted pentagonal pyramidal geometry to six N3- atoms. There are four shorter (2.33 Å) and two longer (2.35 Å) Er–N bond lengths. There are three inequivalent C+3.33+ sites. In the first C+3.33+ site, C+3.33+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. In the second C+3.33+ site, C+3.33+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. In the third C+3.33+ site, C+3.33+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a linear geometry to one Er3+ and one C+3.33+ atom. In the second N3- site, N3- is bonded in a linear geometry to one Er3+ and one C+3.33+ atom. In the third N3- site, N3- is bonded in a linear geometry to one Er3+ and one C+3.33+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KCrCdC6N6O by Materials Project

(K)2(Cr)2(Cd(CN)6)2O2 is Tungsten-derived structured and crystallizes in the cubic F-43m space group. The structure is zero-dimensional and consists of four chromium molecules, four potassium molecules, four water molecules, and four Cd(CN)6 clusters. In each Cd(CN)6 cluster, Cd2+ is bonded in an octahedral geometry to six equivalent N3- atoms. All Cd–N bond lengths are 2.34 Å. C+2.33+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. N3- is bonded in a linear geometry to one Cd2+ and one C+2.33+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on YbFeC6(N3O2)2 by Materials Project

YbFe(CN)6(O2)2 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional and consists of four 1,2,3,4-tetraoxacyclobutane molecules and one YbFe(CN)6 framework. In the YbFe(CN)6 framework, Yb2+ is bonded in a distorted pentagonal pyramidal geometry to six N3- atoms. There are four shorter (2.41 Å) and two longer (2.49 Å) Yb–N bond lengths. Fe2+ is bonded in an octahedral geometry to six C+3.67+ atoms. There is four shorter (1.95 Å) and two longer (1.96 Å) Fe–C bond length. There are two inequivalent C+3.67+ sites. In the first C+3.67+ site, C+3.67+ is bonded in a distorted linear geometry to one Fe2+ and one N3- atom. The C–N bond length is 1.17 Å. In the second C+3.67+ site, C+3.67+ is bonded in a linear geometry to one Fe2+ and one N3- atom. The C–N bond length is 1.17 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a linear geometry to one Yb2+ and one C+3.67+ atom. In the second N3- site, N3- is bonded in a distorted linear geometry to one Yb2+ and one C+3.67+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on FeBiC6(N3O2)2 by Materials Project

FeBi(CN)6(O2)2 crystallizes in the orthorhombic Cmcm space group. The structure is zero-dimensional and consists of four 1,2,3,4-tetraoxacyclobutane molecules; four iron molecules; and four Bi(CN)6 clusters. In each Bi(CN)6 cluster, there are two inequivalent C+3.33+ sites. In the first C+3.33+ site, C+3.33+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. In the second C+3.33+ site, C+3.33+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. Bi3+ is bonded in a distorted pentagonal pyramidal geometry to six N3- atoms. There are four shorter (2.39 Å) and two longer (2.63 Å) Bi–N bond lengths. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted linear geometry to one C+3.33+ and one Bi3+ atom. In the second N3- site, N3- is bonded in a distorted bent 150 degrees geometry to one C+3.33+ and one Bi3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MnH30C6(Se2N3)2 by Materials Project

MnH30(CN)6(Se)4 is alpha Niobium phosphide structured and crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of four MnH30(CN)6 clusters and four Se clusters. In each MnH30(CN)6 cluster, Mn2+ is bonded to six N3- atoms to form MnN6 octahedra that share corners with six CH3N tetrahedra. There are a spread of Mn–N bond distances ranging from 2.31–2.36 Å. There are three inequivalent C1- sites. In the first C1- site, C1- is bonded to one N3- and three H1+ atoms to form CH3N tetrahedra that share a cornercorner with one MnN6 octahedra. The corner-sharing octahedral tilt angles are 60°. The C–N bond length is 1.48 Å. All C–H bond lengths are 1.10 Å. In the second C1- site, C1- is bonded to one N3- and three H1+ atoms to form CH3N tetrahedra that share a cornercorner with one MnN6 octahedra. The corner-sharing octahedral tilt angles are 59°. The C–N bond length is 1.48 Å. All C–H bond lengths are 1.10 Å. In the third C1- site, C1- is bonded to one N3- and three H1+ atoms to form CH3N tetrahedra that share a cornercorner with one MnN6 octahedra. The corner-sharing octahedral tilt angles are 58°. The C–N bond length is 1.48 Å. All C–H bond lengths are 1.10 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a 4-coordinate geometry to one Mn2+, one C1-, and two H1+ atoms. Both N–H bond lengths are 1.03 Å. In the second N3- site, N3- is bonded in a 4-coordinate geometry to one Mn2+, one C1-, and two H1+ atoms. There is one shorter (1.03 Å) and one longer (1.04 Å) N–H bond length. In the third N3- site, N3- is bonded in a 4-coordinate geometry to one Mn2+, one C1-, and two H1+ atoms. There is one shorter (1.02 Å) and one longer (1.03 Å) N–H bond length. There are fifteen inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one C1- 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 C1- atom. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the eleventh H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the twelfth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the thirteenth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the fourteenth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the fifteenth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In each Se cluster, there are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a bent 120 degrees geometry to two Se2- atoms. There are one shorter (2.38 Å) and one longer (2.39 Å) Se–Se bond lengths. In the second Se2- site, Se2- is bonded in a single-bond geometry to one Se2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KTbRuC6(N3O2)2 by Materials Project

KTb(CN)6Ru(O2)2 crystallizes in the orthorhombic Cmcm space group. The structure is two-dimensional and consists of four 1,2,3,4-tetraoxacyclobutane molecules; four ruthenium molecules; and two KTb(CN)6 sheets oriented in the (0, 0, 1) direction. In each KTb(CN)6 sheet, K1+ is bonded in a 6-coordinate geometry to six N3- atoms. There are two shorter (2.88 Å) and four longer (2.97 Å) K–N bond lengths. Tb3+ is bonded in a distorted pentagonal pyramidal geometry to six N3- atoms. There are four shorter (2.37 Å) and two longer (2.46 Å) Tb–N bond lengths. There are two inequivalent C+2.67+ sites. In the first C+2.67+ site, C+2.67+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. In the second C+2.67+ site, C+2.67+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a 2-coordinate geometry to one K1+, one Tb3+, and one C+2.67+ atom. In the second N3- site, N3- is bonded in a distorted linear geometry to one K1+, one Tb3+, and one C+2.67+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NdFeC6(N3O2)2 by Materials Project

FeNd(CN)6(O2)2 crystallizes in the orthorhombic Cmcm space group. The structure is zero-dimensional and consists of four 1,2,3,4-tetraoxacyclobutane molecules; four iron molecules; and four Nd(CN)6 clusters. In each Nd(CN)6 cluster, Nd3+ is bonded in a distorted pentagonal pyramidal geometry to six N3- atoms. There are four shorter (2.45 Å) and two longer (2.52 Å) Nd–N bond lengths. There are two inequivalent C+3.33+ sites. In the first C+3.33+ site, C+3.33+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. In the second C+3.33+ site, C+3.33+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a linear geometry to one Nd3+ and one C+3.33+ atom. In the second N3- site, N3- is bonded in a linear geometry to one Nd3+ and one C+3.33+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on FeC3N3O2 by Materials Project

FeFe(CN)6(O2)2 is Fluorite structured and crystallizes in the cubic F-43m space group. The structure is zero-dimensional and consists of four h20 trihydrate molecules, four iron molecules, and four Fe(CN)6 clusters. In each Fe(CN)6 cluster, Fe3+ is bonded in an octahedral geometry to six equivalent N3- atoms. All Fe–N bond lengths are 2.09 Å. C+3.33+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. N3- is bonded in a linear geometry to one Fe3+ and one C+3.33+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Exploration of Fuel Property Impacts on the Combustion of Late Post Injections Using Binary Blends and High-Reactivity Ether Bioblendstocks

In this study, the impacts of fuel volatility and reactivity on com- bustion stability and emissions were studied in a light-duty single- cylinder research engine for a three-injection catalyst heating oper- ation strategy with late post-injections. N-heptane and blends of farnesane/2,2,4,4,6,8,8-heptamethylnonane were used to study the im- pacts of volatility and reactivity. The effect of increased chemical reac- tivity was also analysed by comparing the baseline #2 diesel operation with a pure blend of mono-ether components (CN > 100) representa- tive of potential high cetane oxygenated bioblendstocks and a 25 vol.% blend of the mono-ether blend and #2 diesel with a cetane number (CN) of 55. At constant reactivity, little to no variation in combustion performance was observed due to differences in volatility, whereas in- creased reactivity improved combustion stability and efficiency at late injection timings. Fuels with higher reactivity were found to reduce engine-out hydrocarbon and carbon monoxide emissions while also achieving stable combustion at post-injection timings later than those achievable with #2 diesel fuel. The pure ether blend had the latest achievable post-injection timing of +30.5 CAD while still maintaining stable combustion (coefficient of variation of gross-indicated mean ef- fective pressure < 5%). With post-injection timing adjusted to achieve a matched exhaust temperature of 300 °C, the ether-diesel CN 55 blend was observed to have slightly higher thermal efficiency in comparison to the baseline #2 diesel fuel. The results also indicate that cetane num- ber may serve as a good indicator of combustion characteristics at late injection timings used for aftertreatment thermal management opera- tion.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2020

A Mystery in Chamaeleon: Serendipitous Discovery of a Galactic Symbiotic Nova

We present the serendipitous discovery of a low optical-luminosity nova occurring in a D-type symbiotic binary star system in the Milky Way. We lay out the extensive archival data alongside new follow-up observations related to the stellar object CN Cha in the constellation of Chamaeleon. The object had long period (250 days), high amplitude (3 mag) optical variability in its recent past, preceding an increase in optical brightness by 8 magnitudes and a persistence at this brightness for about 3 yr, followed by a period of 1.4 mag yr{sup −1} dimming. The object’s current optical luminosity seems to be dominated by Hα emission, which also exhibits blueshifted absorption (a P-Cygni-like profile). After consideration of a number of theories to explain these myriad observations, we determine that CN Cha is most likely a symbiotic (an evolved-star–white-dwarf binary) system that has undergone a long-duration, low optical brightness, nova, placing it squarely in the class of so-called “slow novae,” of which there are only a few known examples. The duration of the optical plateau in CN Cha would make it the shortest timescale plateau of any known slow symbiotic novae.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

Exploration of Fuel Property Impacts on the Combustion of Late Post Injections Using Binary Blends and High-Reactivity Ether Bioblendstocks

In this study, the impacts of fuel volatility and reactivity on combustion stability and emissions were studied in a light-duty single-cylinder research engine for a three-injection catalyst heating operation strategy with late post-injections. Here, N-heptane and blends of farnesane/2,2,4,4,6,8,8-heptamethylnonane were used to study the impacts of volatility and reactivity. The effect of increased chemical reactivity was also analysed by comparing the baseline #2 diesel operation with a pure blend of mono-ether components (CN > 100) representative of potential high cetane oxygenated bioblendstocks and a 25 vol.% blend of the mono-ether blend and #2 diesel with a cetane number (CN) of 55. At constant reactivity, little to no variation in combustion performance was observed due to differences in volatility, whereas increased reactivity improved combustion stability and efficiency at late injection timings. Fuels with higher reactivity were found to reduce engine-out hydrocarbon and carbon monoxide emissions while also achieving stable combustion at post-injection timings later than those achievable with #2 diesel fuel. The pure ether blend had the latest achievable post-injection timing of +30.5 CAD while still maintaining stable combustion (coefficient of variation of gross-indicated mean effective pressure < 5%). With post-injection timing adjusted to achieve a matched exhaust temperature of 300 °C, the ether-diesel CN 55 blend was observed to have slightly higher thermal efficiency in comparison to the baseline #2 diesel fuel. The results also indicate that cetane number may serve as a good indicator of combustion characteristics at late injection timings used for aftertreatment thermal management operation.

09 BIOMASS FUELS↗
DOE OSTI2021

Soil Temperature and Moisture, Council Road Mile Marker 71, Seward Peninsula, Alaska, beginning 2016

Daily averages of soil temperature and moisture measured once every hour at different heights, as well as daily averages of hourly measured snow depths located at Intensive Monitoring Stations at Council Road Mile Marker 71 site. Deployed at each site is an Onset HOBO U30 data logger with five smart temperature sensors and three smart soil moisture sensors (10HS). Three sites (CN_IS_4, CN_IS_6A, CN_IS_7) are equipped with a snow depth sensor. Data are retrieved annually since 2016. Contains 53 *.CSV files including a file inventory list by year. Data files have header rows, NaN fields indicate invalid or missing data, and negative vertical offsets are above ground. The Next-Generation Ecosystem Experiments: Arctic (NGEE Arctic), was a research effort to reduce uncertainty in Earth System Models by developing a predictive understanding of carbon-rich Arctic ecosystems and feedbacks to climate. NGEE Arctic was supported by the Department of Energy's Office of Biological and Environmental Research. The NGEE Arctic project had two field research sites: 1) located within the Arctic polygonal tundra coastal region on the Barrow Environmental Observatory (BEO) and the North Slope near Utqiagvik (Barrow), Alaska and 2) multiple areas on the discontinuous permafrost region of the Seward Peninsula north of Nome, Alaska. Through observations, experiments, and synthesis with existing datasets, NGEE Arctic provided an enhanced knowledge base for multi-scale modeling and contributed to improved process representation at global pan-Arctic scales within the Department of Energy's Earth system Model (the Energy Exascale Earth System Model, or E3SM), and specifically within the E3SM Land Model component (ELM).

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1976

Development of polyphenylquinoxaline graphite composites

Six polyphenylquinoxalines (PPQ) containing pendant cyano (CN) groups were synthesized. The polymers were characterized in terms of inherent viscosity, glass transition temperature, softening temperature and weight loss due to aging in air at 316 C (600 F). The potential for crosslinking PPQs by trimerization of pendant CN groups was investigated. A polymer derived from 1 mole 3,3,4,4 -tetraaminobenzophenone, .2 mole p-bis(p -cyanophenoxyphenylglyoxalyl)benzene and .8 mole p-bis(phenylglyoxalyl)benzene was selected for more extensive characterization in HM-S graphite fiber-reinforced composites. Mechanical properties were determined using composites made from HM-S fiber and polymer and composites made from HM-S fiber, polymer and a potential CN group trimerization catalyst. Composite mechanical properties, inter-laminar shear strength and flexure properties, were determined over the temperature range of +21 C to 316 C.

Shdo, J. D.↗
NASA NTRS1978

Vertical profiles of condensation nuclei

Condensation nuclei measurements using a low supersaturation (about 10%) thermal gradient diffusion cloud chamber (TGDCC) and a high supersaturation (about 200%) expansion type instrument were compared on a series of three balloon flights over Laramie, Wyoming. In general, the two instruments produced similar vertical profiles but some discrepancies remain unexplained. Agreement between the two would indicate that the low supersaturations used in the TGDCC were still large enough to cause the instrument to count essentially all of the particles present. The TGDCC condensation nuclei (CN) counter was flown at several sites in both the Northern and Southern Hemispheres. The results indicate the existence of a relative maximum in the CN mixing ratio associated with the upper equatorial troposphere and what appears to be a worldwide constant mixing ratio of CN above 20-25 km.

Rosen, J. M.↗
NASA NTRS1980

Spectrophotometry of Comet West

Postperihelion observations of Comet West (1975n = 1976 VI) have been made with a Fourier transform spectrometer at heliocentric distances from 0.57 to 1.68 AU. Measurements were made of the emission bands of C2, CN, C3, CH, and NH2, as well as the emission lines of Na D and forbidden (O I), and the flux in the continuum in nine different bandpasses. Several ratios of the band strengths of CN have been used to determine the two free parameters in the fluorescence equilibrium model of CN of Danks and Arpigny (1973). From the values of the parameters it is inferred that the vibrational transition probability for the ground electronic state is between 0.025 and 0.075 per sec and that the ratio of oscillator strengths between the (0-0) bands of the violet and red systems is between 25 and 30. When corrected for field-of-view effects, NH2 shows no systematic variation in abundance relative to C2 while CH shows a small increase. The cometary continuum is found to be slightly redder than the solar continuum, consistent with results for other bright, dusty comets. The equivalent width of the Delta u = 0 sequence of C2 shows a marked decrease at r(H) = 1.2 AU.

Ahearn, M. F.↗
NASA NTRS1984

Spectrophotometry of 17 comets. I - The emission features

The present 112 sets of image dissector scanner data were obtained at Lick Observatory from 17 comets during a 2.5-yr period, 1980-1982. Results obtained include column densities for CN, C3, CH, C2, and forbidden line O I, new Haser parent scale lengths for CN, C3, and C2, and a large body of data on the composition of cometary comae as a function of heliocentric distance. Particularly notable is the well-defined C2-to-CN ratio, which decreases roughly as r to the -1.4 power out to r of about 1.8 AU, and then falls precipitously. Although there is considerable chemical uniformity in most comets studied, two (P/Borrelly and P/Swift-Gehrels) appear significantly deficient in both C2 and C3. The apparent systematics within the crude Haser paradigm offer suggestions for more realistic chemical modelling studies.

Newburn, R. L., Jr.↗
NASA NTRS1985

Delayed production of sulfuric acid condensation nuclei in the polar stratosphere from El Chichon volcanic vapors

It is pointed out that measurements of the vertical profiles of atmospheric condensation nuclei (CN) have been conducted since 1973. Studies with a new instrument revealed that the CN concentration undergoes a remarkable annual variation in the 30-km region characterized by a large increase in the late winter/early spring period with a subsequent decay during the remainder of the year. The event particles are observed to be volatile at 150 C, suggesting a sulfuric acid-water composition similar to that found in the normal 20 km aerosol layer. The development of about 10 to the 7th metric tons of sulfuric acid aerosol following the injection of sulfurous gases by El Chichon in April 1982, prompted Hofmann and Rosen (1983) to predict a very large CN event for 1983. The present investigation is concerned with the actual observation of the predicted event. Attention is given to the observation of a very large increase of what appear to be small sulfuric acid droplets at 30-km altitude in January 1983 over Laramie, WY, in January 1983.

Hofmann, D. J.↗
NASA NTRS1986

Optical probing of comet Halley from the Giotto spacecraft

The Halley optical probe experiment (HOPE) aboard the Giotto spacecraft has provided the first measurements of the optical properties of the dust and of some gaseous species (CN, C2, CO/+/ and OH) from inside the coma of comet Halley. The dust spatial distribution, inferred from sunlight scattering, obeys an r exp -2 law for distances from the nucleus r greater than about 2,000 km. The more rapid increase of dust density with distance observed in the innermost coma probably reflects the presence of a jet, or a surge of activity within a few hours before closest approach. The CN and OH signals increase more slowly than the dust signals, but faster than predicted by a simple model (of solar-excited resonance fluorescence) for the distribution of these species. This effect is probably caused in part by the dust contribution, as well as by the production from parent molecules of OH and CN in an excited state.

Levasseur-Regourd, A. C.↗