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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on ZnH6C2(SO3)2 by Materials Project

ZnC2H6(SO3)2 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. Zn2+ is bonded in a distorted octahedral geometry to six O2- atoms. There are a spread of Zn–O bond distances ranging from 2.02–2.46 Å. There are two inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a trigonal non-coplanar geometry to two H1+ and one O2- atom. Both C–H bond lengths are 1.10 Å. The C–O bond length is 1.40 Å. In the second C4+ site, C4+ is bonded in a trigonal non-coplanar geometry to two H1+ and one O2- atom. Both C–H bond lengths are 1.10 Å. The C–O bond length is 1.41 Å. There are six inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a distorted single-bond geometry to two O2- atoms. There is one shorter (1.00 Å) and one longer (1.65 Å) H–O bond length. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C4+ atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C4+ atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one C4+ atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one C4+ atom. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted water-like geometry to two O2- atoms. There is one shorter (1.54 Å) and one longer (1.56 Å) S–O bond length. In the second S2- site, S2- is bonded in a distorted water-like geometry to two O2- atoms. There is one shorter (1.54 Å) and one longer (1.56 Å) S–O bond length. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Zn2+ and one S2- atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one Zn2+ and one S2- atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Zn2+, one C4+, and one H1+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to one Zn2+ and one S2- atom. In the fifth O2- site, O2- is bonded in a trigonal planar geometry to one Zn2+, one H1+, and one S2- atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Zn2+, one C4+, and one H1+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS2020

Sub-Zero Alteration in an Isotopically Heavy Brine Preserved in a Pristine H Chondrite Xenolith

Introduction: Brecciated H chondrites host a variety of xenoliths, including unshocked, phyllo- silicate-rich carbonaceous chondrites (CCs). The brecciated H chondrite Zag (H3-6) is one of two chondrites to host macroscopic (1 - 5mm), xenolithic crystals of halite (NaCl) with aqueous fluid inclusions and organics. A ~1cm CC xenolith in Zag (Zag clast) has mineralogy similar to CI chondrites, but it has a unique bulk oxygen isotopic composition among all meteorites (Δ(exp 17)O = 1.49 ± 0.04 ‰, δ(exp 18)O = 22.38 ± 0.17 ‰). The Zag clast encloses halite in its matrix, linking the coarse, matrix halite and the xenolith to the same parent object, suggested to be hydrovolcanically active. Its bulk C and N contents are the highest among chondrites and bulk δ(exp 15)N is similar to CR chondrites and Bells. Insoluble organic material (IOM) in the Zag clast has δD and δ(exp 15)N “hotspots”, also similar to CR chondrites and Bells (C2-ung.). We provide further isotopic characterization of the Zag clast to constrain the formation temperature and origin of its primary and secondary components.

Frank, D. R.↗
DOE OSTI2022

316L Stainless Steel Wire Arc Additive Manufacturing and Characterization for Potential SNF Canister Production

In this paper, 316L stainless steel (316L SS) straight walls, curved walls, and vessels were printed by wire arc additive manufacturing (WAAM) using the 316L SS welding wire, to demonstrate the feasibility of spent nuclear fuel (SNF) canisters using this advanced manufacturing technique. Helium leak test with leak tight criteria of 1 × 10-7 ref-cc/s were performed on printed vessels with various wall thickness, and testing pressures were from 0.345 MPa (50 psi) to 1.724 MPa (250 psi). Printed wall microstructures were characterized using optical microscopy (OM) and scanning electron microscopy (SEM). Tensile specimens were machined out from printed walls along the length, height, and thickness directions, respectively, and tested at different temperature conditions, room temperature, 80 °C, 150 °C and 250 °C, respectively. Results showed t hat, all five WAAM-printed canisters with different thickness passed the helium leaktight criteria of radioactive materials containers by the ANSI N14.5; Dispersed micrometer-level size inclusions/voids were observed at printed wall cross sections, dendritic microstructures were found with grain size variation through the welding torch shifting direction, and very small amount of δ-ferrite and σ-phase were also observed in those cross sections; The printed walls were ductile, all tensile specimens broke with large plastic deformation/elongation and without brittle failure, and printed specimens yield strengths and tensile strengths under room temperature and 80 °C conditions are higher than minimum values of 316L SS for pressure vessels and for general applications at room temperature required by the ASTM standard, respectively.

Tang, Wei↗
DOE OSTI2020

Materials Data on SbC6S2F19 by Materials Project

C2SbS2F7(CF3)4 crystallizes in the monoclinic Cc space group. The structure is one-dimensional and consists of sixteen fluoroform molecules and two C2SbS2F7 ribbons oriented in the (0, 0, 1) direction. In each C2SbS2F7 ribbon, there are two inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in an L-shaped geometry to two S2- atoms. There is one shorter (1.84 Å) and one longer (1.87 Å) C–S bond length. In the second C4+ site, C4+ is bonded in an L-shaped geometry to two S2- atoms. There is one shorter (1.84 Å) and one longer (1.86 Å) C–S bond length. Sb1- is bonded in an octahedral geometry to six F1- atoms. There are a spread of Sb–F bond distances ranging from 1.91–1.95 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted single-bond geometry to two C4+ and one F1- atom. The S–F bond length is 1.57 Å. In the second S2- site, S2- is bonded in a distorted square co-planar geometry to two C4+ and two F1- atoms. There are one shorter (2.80 Å) and one longer (2.89 Å) S–F bond lengths. There are seven inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one Sb1- atom. In the second F1- site, F1- is bonded in a single-bond geometry to one Sb1- atom. In the third F1- site, F1- is bonded in a distorted single-bond geometry to one Sb1- and one S2- atom. In the fourth F1- site, F1- is bonded in a distorted single-bond geometry to one Sb1- atom. In the fifth F1- site, F1- is bonded in a single-bond geometry to one S2- atom. In the sixth F1- site, F1- is bonded in a single-bond geometry to one Sb1- atom. In the seventh F1- site, F1- is bonded in a distorted single-bond geometry to one Sb1- and one S2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KHCN4O5 by Materials Project

(KCN2O5)2N2(NH)2 crystallizes in the monoclinic Cc space group. The structure is three-dimensional and consists of four ammonia molecules, four ammonia molecules, and one KCN2O5 framework. In the KCN2O5 framework, K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.82–3.07 Å. C4+ is bonded in a single-bond geometry to one O2- atom. The C–O bond length is 1.23 Å. There are two inequivalent N1+ sites. In the first N1+ site, N1+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.23 Å) and one longer (1.24 Å) N–O bond length. In the second N1+ site, N1+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.25 Å) and one longer (1.27 Å) N–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one K1+ and one N1+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent K1+ and one N1+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one K1+ and one N1+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one K1+ and one N1+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent K1+ and one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Approximating large-basis coupled-cluster theory vibrational frequencies using focal-point approximations

The focal-point approximation can be used to estimate a high-accuracy, slow quantum chemistry computation by combining several lower-accuracy, faster computations. We examine the performance of focal-point methods by combining second-order Møller–Plesset perturbation theory (MP2) with coupled-cluster singles, doubles, and perturbative triples [CCSD(T)] for the calculation of harmonic frequencies and that of fundamental frequencies using second-order vibrational perturbation theory (VPT2). In contrast to standard CCSD(T), the focal-point CCSD(T) method approaches the complete basis set (CBS) limit with only triple-ζ basis sets for the coupled-cluster portion of the computation. The predicted harmonic and fundamental frequencies were compared with the experimental values for a set of 20 molecules containing up to six atoms. Here, the focal-point method combining CCSD(T)/aug-cc-pV(T + d)Z with CBS-extrapolated MP2 has mean absolute errors vs experiment of only 7.3 cm −1 for the fundamental frequencies, which are essentially the same as the mean absolute error for CCSD(T) extrapolated to the CBS limit using the aug-cc-pV(Q + d)Z and aug-cc-pV(5 + d)Z basis sets. However, for H 2 O, the focal-point procedure requires only 3% of the computation time as the extrapolated CCSD(T) result, and the cost savings will grow for larger molecules.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2000

Deterrent Concentration Measurement with FTIR and Subsequent Ballistic Performance in Medium Caliber Propellant

To meet ballistic requirements, medium and small caliber propellants use deterrent coatings to obtain burn rate progressivity. The required amount and distribution of deterrent varies between gun systems, propellant types, and often between lots. Micro Fourier Transform Infrared (FTIR) spectroscopy was used to measure deterrent gradients in RP36 propellants coated with methyl centralite (MC) at different deterrent levels and different processing conditions. The aromatic C-C bonds at 1496 cm(exp -1) wavenumber were used to monitor the deterrent profiles through the grain. Deterrent gradients measured with FTIR spectroscopy were then used to estimate burn rate gradients in the deterred grains. Burn rates were calculated from literature models and from closed bomb data of RP36 containing uniform deterrent concentration. Finally, the burn rate gradients were input into an IBHFG2 model of a 200 cc-closed bomb. The early flame spreading portion of the closed bomb ballistic cycle (0 to 0.2 P/Pmax) was roughly modeled by dividing the charge up into five propellant decks and igniting them at different times in the ballistic cycle. Pressure traces and vivacity curves from closed bomb shots were compared to predictions. In addition to the burn rate gradient, the closed bomb pressure trace was heavily dependent on ignition and flame spread. These two phenomena were not readily distinguishable from one another in deterred grains. The same RP-36 propellant was shot in a 25 mm M793TP round which was again modeled with IBHVG2. Peak pressure and muzzle velocity were accurately modeled when erosive burning effects were empirically factored into the model.

Furrow, Keith W.↗
DOE OSTI2022

Ultrafast infrared transient absorption spectroscopy of gas-phase Ni(CO) 4 photodissociation at 261 nm

Here, we employ ultrafast mid-infrared transient absorption spectroscopy to probe the rapid loss of carbonyl ligands from gas-phase nickel tetracarbonyl following ultraviolet photoexcitation at 261 nm. Here, nickel tetracarbonyl undergoes prompt dissociation to produce nickel tricarbonyl in a singlet excited state; this electronically excited tricarbonyl loses another CO group over tens of picoseconds. Our results also suggest the presence of a parallel, concerted dissociation mechanism to produce nickel dicarbonyl in a triplet excited state, which likely dissociates to nickel monocarbonyl. Mechanisms for the formation of these photoproducts in multiple electronic excited states are theoretically predicted with one-dimensional cuts through the potential energy surfaces and computation of spin–orbit coupling constants using equation of motion coupled cluster methods (EOM-CC) and coupled cluster theory with single and double excitations (CCSD). Bond dissociation energies are calculated with CCSD, and anharmonic frequencies of ground and excited state species are computed using density functional theory (DFT) and time-dependent density functional theory (TD-DFT).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1977

Development of a thermal diode heat pipe for cryogenic applications

The paper describes the development of a cryogenic thermal diode heat pipe for space flight applications. The diode has ethane working fluid, and uses the liquid blockage technique with an internal blocking orifice, to accomplish shutoff in the reverse mode. The pipe is 0.635 cm OD by 75.82 cm long including a 2.54 cc excess liquid reservoir. Experimental data are presented for forward mode throughput vs tilt, film coefficients, and reverse mode characteristics. Transport capacity is 1000 w-cm at 2.5 cm tilt. Evaporator and condenser film coefficients were 0.92 and 1.64 w/sq cm K, respectively.

Quadrini, J. A.↗
DOE OSTI2020

Quark structure of the $\chi _{\mathrm{c}}(3P)$ and X(4274) resonances and their strong and radiative decays

We calculate the masses of χc(3P) states with threshold corrections in a coupled-channel model. The model was recently applied to the description of the properties of χc(2P) and χb(3P) multiplets (Ferretti and Santopinto in Phys Lett B 789:550, 2019]. We also compute the open-charm strong decay widths of the χc(3P) states and their radiative transitions. According to our predictions, the χc(3P) states should be dominated by the charmonium core, but they may also show small meson-meson components. The X(4274) is interpreted as a cc¯ χc1(3P) state. More information on the other members of the χc(3P) multiplet, as well as a more rigorous analysis of the X(4274)’s decay modes, are needed to provide further indications on the quark structure of the previous resonance.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS1979

A controlled rate freeze/thaw system for cryopreservation of biological materials

A system which allows programmable temperature-time control for a 5 cc sample volume of an arbitrary biological material was constructed. Steady state and dynamic temperature control was obtained by supplying heat to the sample volume through resistive elements constructed as an integral part of the sample container. For cooling purposes, this container was totally immersed into a cold heat sink. Sample volume thermodynamic property data were obtained by measurements of heater power and heat flux through the container walls. Using a mixture of dry ice and alcohol at -79 C, sample volume was controlled from +40 C to -60 C at rates from steady state to + or - 65 C/min. Steady state temperature precision was better than 0.2 C while the dynamic capability depends on the temperature rate of change as well as the thermal mass of the sample and the container.

Anselmo, V. J.↗
DOE OSTI2020

Materials Data on CoH17C(NO)8 by Materials Project

CoCH17(N3O)2(NO3)2 crystallizes in the monoclinic Cc space group. The structure is zero-dimensional and consists of eight nitric acid molecules and four CoCH17(N3O)2 clusters. In each CoCH17(N3O)2 cluster, Co3+ is bonded in an octahedral geometry to five N1- and one O2- atom. There are a spread of Co–N bond distances ranging from 2.11–2.15 Å. The Co–O bond length is 1.93 Å. C4+ is bonded in a trigonal planar geometry to one N1- and two O2- atoms. The C–N bond length is 1.37 Å. There is one shorter (1.26 Å) and one longer (1.32 Å) C–O bond length. There are six inequivalent N1- sites. In the first N1- site, N1- is bonded in a distorted trigonal non-coplanar geometry to one Co3+ and three H1+ atoms. There is one shorter (1.02 Å) and two longer (1.03 Å) N–H bond length. In the second N1- site, N1- is bonded in a distorted trigonal non-coplanar geometry to one Co3+ and three H1+ atoms. All N–H bond lengths are 1.03 Å. In the third N1- site, N1- is bonded in a distorted trigonal non-coplanar geometry to one Co3+ and three H1+ atoms. There is one shorter (1.02 Å) and two longer (1.03 Å) N–H bond length. In the fourth N1- site, N1- is bonded in a distorted trigonal non-coplanar geometry to one Co3+ and three H1+ atoms. There is one shorter (1.02 Å) and two longer (1.03 Å) N–H bond length. In the fifth N1- site, N1- is bonded in a distorted trigonal non-coplanar geometry to one Co3+ and three H1+ atoms. All N–H bond lengths are 1.03 Å. In the sixth N1- site, N1- is bonded in a distorted trigonal planar geometry to one C4+ and two H1+ atoms. There is one shorter (1.01 Å) and one longer (1.02 Å) N–H bond length. There are seventeen inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the eleventh H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the twelfth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the thirteenth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the fourteenth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the fifteenth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the sixteenth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. In the seventeenth H1+ site, H1+ is bonded in a single-bond geometry to one N1- atom. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Co3+ and one C4+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NiH3C5NO6 by Materials Project

NiH3(CO2)3C2N crystallizes in the monoclinic Cc space group. The structure is three-dimensional and consists of four ch3nc molecules and one NiH3(CO2)3 framework. In the NiH3(CO2)3 framework, Ni2+ is bonded in an octahedral geometry to six O2- atoms. There are two shorter (2.02 Å) and four longer (2.04 Å) Ni–O bond lengths. There are three inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a trigonal planar geometry to one H1+ and two O2- atoms. The C–H bond length is 1.10 Å. Both C–O bond lengths are 1.27 Å. In the second C2+ site, C2+ is bonded in a trigonal planar geometry to one H1+ and two O2- atoms. The C–H bond length is 1.10 Å. Both C–O bond lengths are 1.27 Å. In the third C2+ site, C2+ is bonded in a trigonal planar geometry to one H1+ and two O2- atoms. The C–H bond length is 1.10 Å. Both C–O bond lengths are 1.27 Å. There are three inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one Ni2+ and one C2+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one Ni2+ and one C2+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to one Ni2+ and one C2+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to one Ni2+ and one C2+ atom. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to one Ni2+ and one C2+ atom. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to one Ni2+ and one C2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AlZnB5H21C6(NO2)5 by Materials Project

Al(BO2)5ZnC6N5H21 crystallizes in the monoclinic Cc space group. The structure is three-dimensional and consists of four ZnC6N5H21 clusters and one Al(BO2)5 framework. In each ZnC6N5H21 cluster, Zn2+ is bonded in a trigonal bipyramidal geometry to five N3- atoms. There are a spread of Zn–N bond distances ranging from 2.07–2.26 Å. There are six inequivalent C1- sites. In the first C1- site, C1- is bonded in a distorted trigonal non-coplanar geometry to one N3- and two H1+ atoms. The C–N bond length is 1.48 Å. Both C–H bond lengths are 1.10 Å. In the second C1- site, C1- is bonded in a distorted trigonal non-coplanar geometry to one N3- and two H1+ atoms. The C–N bond length is 1.47 Å. Both C–H bond lengths are 1.10 Å. In the third C1- site, C1- is bonded in a distorted trigonal non-coplanar geometry to one N3- and two H1+ atoms. The C–N bond length is 1.48 Å. Both C–H bond lengths are 1.10 Å. In the fourth C1- site, C1- is bonded in a distorted trigonal non-coplanar geometry to one N3- and two H1+ atoms. The C–N bond length is 1.47 Å. Both C–H bond lengths are 1.10 Å. In the fifth C1- site, C1- is bonded in a distorted trigonal non-coplanar geometry to one N3- and two H1+ atoms. The C–N bond length is 1.47 Å. Both C–H bond lengths are 1.10 Å. In the sixth C1- site, C1- is bonded in a distorted trigonal non-coplanar geometry to one N3- and two H1+ atoms. The C–N bond length is 1.48 Å. Both C–H bond lengths are 1.10 Å. There are five inequivalent N3- sites. In the first N3- site, N3- is bonded to one Zn2+, one C1-, and two H1+ atoms to form distorted corner-sharing NZnH2C tetrahedra. There is one shorter (1.03 Å) and one longer (1.04 Å) N–H bond length. In the second N3- site, N3- is bonded to one Zn2+, one C1-, and two H1+ atoms to form distorted corner-sharing NZnH2C tetrahedra. Both N–H bond lengths are 1.03 Å. In the third N3- site, N3- is bonded to one Zn2+, one C1-, and two H1+ atoms to form distorted corner-sharing NZnH2C tetrahedra. Both N–H bond lengths are 1.03 Å. In the fourth N3- site, N3- is bonded to one Zn2+, one C1-, and two H1+ atoms to form distorted corner-sharing NZnH2C tetrahedra. There is one shorter (1.02 Å) and one longer (1.03 Å) N–H bond length. In the fifth N3- site, N3- is bonded in a 4-coordinate geometry to one Zn2+, two C1-, and one H1+ atom. The N–H bond length is 1.02 Å. There are twenty-one inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one C1- 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 C1- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one C1- 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 C1- atom. In the twelfth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the thirteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the fourteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the fifteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the sixteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the seventeenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the eighteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the nineteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the twentieth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the twenty-first H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the Al(BO2)5 framework, Al3+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.75 Å) and two longer (1.76 Å) Al–O bond length. There are five inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.35–1.41 Å. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.35–1.40 Å. In the third B3+ site, B3+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of B–O bond distances ranging from 1.47–1.50 Å. In the fourth B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.35–1.42 Å. In the fifth B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.35–1.42 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to one Al3+ and one B3+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the sixth O2- site, O2- is bonded in a linear geometry to one Al3+ and one B3+ atom. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the eighth O2- site, O2- is bonded in a linear geometry to one Al3+ and one B3+ atom. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to one Al3+ and one B3+ atom. In the tenth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GaPH9C3Cl3O by Materials Project

GaC3PH9OCl3 is beta Sn-like structured and crystallizes in the monoclinic Cc space group. The structure is zero-dimensional and consists of four GaC3PH9OCl3 clusters. Ga3+ is bonded to one O2- and three Cl1- atoms to form GaCl3O tetrahedra that share a cornercorner with one PC3O tetrahedra. The Ga–O bond length is 1.88 Å. All Ga–Cl bond lengths are 2.19 Å. There are three inequivalent C4- sites. In the first C4- site, C4- is bonded to one P5+ and three H1+ atoms to form distorted corner-sharing CPH3 tetrahedra. The C–P bond length is 1.80 Å. All C–H bond lengths are 1.10 Å. In the second C4- site, C4- is bonded to one P5+ and three H1+ atoms to form distorted corner-sharing CPH3 tetrahedra. The C–P bond length is 1.79 Å. All C–H bond lengths are 1.10 Å. In the third C4- site, C4- is bonded to one P5+ and three H1+ atoms to form distorted corner-sharing CPH3 tetrahedra. The C–P bond length is 1.79 Å. All C–H bond lengths are 1.10 Å. P5+ is bonded to three C4- and one O2- atom to form PC3O tetrahedra that share a cornercorner with one GaCl3O tetrahedra. The P–O bond length is 1.55 Å. There are seven inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom. O2- is bonded in a bent 150 degrees geometry to one Ga3+ and one P5+ atom. There are three inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Ga3+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Ga3+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Ga3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Formation of phenanthrenyl radicals via the reaction of acenaphthyl with acetylene

Ab initio G3(MP2,CC)/B3LYP/6–31G** calculations of the potential energy surface for the reaction of 3-acenaphthyl radical with acetylene were combined with Rice-Ramsperger-Kassel-Marcus Master Equation calculations of the temperature- and pressure-dependent reaction rate constants and product branching ratios with the goal to examine the transformation of an edge five-membered ring into a six-membered one. The reaction mechanism has been shown to contain two stages: (1) the formation of 3-ethynylacenaphthylene + H in the 3-acenaphthyl + C 2 H 2 reaction via acetylene addition to the radical site and an H loss, (2) the formation of the 1-phenanthrenyl radical in the 3-ethynylacenaphthylene + H reaction via H addition to the five-membered ring followed by the ring flip. The results of kinetic modeling show this pathway being faster than the pathway proposed earlier featuring the CCH chemisorption on the six-membered ring without involvement of the five-membered ring. A kinetic test demonstrated the dominance of the former pathway for the formation of pyrene from naphthalene. Here, it is expected that the new mechanism plays a major role in the transformation of five-membered rings on edges of PAH structures.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1993

Simulation of possible regolith optical alteration effects on carbonaceous chondrite meteorites

As the spectral reflectance search continues for links between meteorites and their parent body asteroids, the effects of optical surface alteration processes need to be considered. We present the results of an experimental simulation of the melting and recrystallization that occurs to a carbonaceous chondrite meteorite regolith powder upon heating. As done for the ordinary chondrite meteorites, we show the effects of possible parent-body regolith alteration processes on reflectance spectra of carbonaceous chondrites (CC's). For this study, six CC's of different mineralogical classes were obtained from the Antarctic Meteorite Collection: two CM meteorites, two CO meteorites, one CK, and one CV. Each sample was ground with a ceramic mortar and pestle to powders with maximum grain sizes of 180 and 90 microns. The reflectance spectra of these powders were measured at RELAB (Brown University) from 0.3 to 2.5 microns. Following comminution, the 90 micron grain size was melted in a nitrogen controlled-atmosphere fusion furnace at an approximate temperature of 1700 C. The fused sample was immediately held above a flow of nitrogen at 0 C for quenching. Following melting and recrystallization, the samples were reground to powders, and the reflectance spectra were remeasured. The effects on spectral reflectance for a sample of the CM carbonaceous chondrite called Murchison are shown.

Clark, Beth E.↗
NASA NTRS2006

Numerical Issues for Circulation Control Calculations

Steady-state and time-accurate two-dimensional solutions of the compressible Reynolds-averaged Navier- Stokes equations are obtained for flow over the Lockheed circulation control (CC) airfoil and the General Aviation CC (GACC) airfoil. Numerical issues in computing circulation control flows such as the effects of grid resolution, boundary and initial conditions, and unsteadiness are addressed. For the Lockheed CC airfoil computed solutions are compared with detailed experimental data, which include velocity and Reynolds stress profiles. Three turbulence models, having either one or two transport equations, are considered. Solutions are obtained on a sequence of meshes, with mesh refinement primarily concentrated on the airfoil circular trailing edge. Several effects related to mesh refinement are identified. For example, sometimes sufficient mesh resolution can exclude nonphysical solutions, which can occur in CC airfoil calculations. Also, sensitivities of the turbulence models with mesh refinement are discussed. In the case of the GACC airfoil the focus is on the difference between steady-state and time-accurate solutions. A specific objective is to determine if there is self-excited vortex shedding from the jet slot lip.

Swanson, Roy C., Jr.↗