Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Rh”

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 631 records · Page 35
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on HfGeRh by Materials Project

HfRhGe crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Hf is bonded in a 11-coordinate geometry to six equivalent Rh and five Ge atoms. There are two shorter (2.94 Å) and four longer (3.13 Å) Hf–Rh bond lengths. There are four shorter (2.79 Å) and one longer (2.80 Å) Hf–Ge bond lengths. Rh is bonded in a 12-coordinate geometry to six equivalent Hf, two equivalent Rh, and four Ge atoms. Both Rh–Rh bond lengths are 2.86 Å. There are two shorter (2.54 Å) and two longer (2.56 Å) Rh–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to six equivalent Hf and three equivalent Rh atoms. In the second Ge site, Ge is bonded in a 9-coordinate geometry to three equivalent Hf and six equivalent Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NbRh2 by Materials Project

NbRh2 crystallizes in the monoclinic P2/m space group. The structure is three-dimensional. Nb is bonded in a 12-coordinate geometry to nine Rh atoms. There are a spread of Nb–Rh bond distances ranging from 2.74–2.80 Å. There are three inequivalent Rh sites. In the first Rh site, Rh is bonded to six equivalent Nb atoms to form a mixture of distorted corner, edge, and face-sharing RhNb6 cuboctahedra. In the second Rh site, Rh is bonded to four equivalent Nb atoms to form a mixture of distorted corner and edge-sharing RhNb4 cuboctahedra. In the third Rh site, Rh is bonded in a distorted linear geometry to two equivalent Nb atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ti2FeB2Ru4Rh by Materials Project

Ti2Ru4FeRhB2 crystallizes in the monoclinic P2/m space group. The structure is three-dimensional. there are two inequivalent Ti sites. In the first Ti site, Ti is bonded in a 12-coordinate geometry to eight Ru, two equivalent Rh, and three B atoms. There are a spread of Ti–Ru bond distances ranging from 2.73–2.90 Å. Both Ti–Rh bond lengths are 2.95 Å. There are a spread of Ti–B bond distances ranging from 2.56–2.88 Å. In the second Ti site, Ti is bonded in a 7-coordinate geometry to eight Ru, two equivalent Rh, and three B atoms. There are a spread of Ti–Ru bond distances ranging from 2.70–2.92 Å. Both Ti–Rh bond lengths are 2.81 Å. There are one shorter (2.64 Å) and two longer (2.78 Å) Ti–B bond lengths. There are five inequivalent Ru sites. In the first Ru site, Ru is bonded in a 8-coordinate geometry to four Ti, two equivalent Fe, and two equivalent B atoms. Both Ru–Fe bond lengths are 2.53 Å. Both Ru–B bond lengths are 2.15 Å. In the second Ru site, Ru is bonded in a 8-coordinate geometry to four Ti, two equivalent Fe, and two equivalent B atoms. Both Ru–Fe bond lengths are 2.53 Å. Both Ru–B bond lengths are 2.17 Å. In the third Ru site, Ru is bonded in a 8-coordinate geometry to four Ti, two equivalent Fe, and two equivalent B atoms. Both Ru–Fe bond lengths are 2.55 Å. Both Ru–B bond lengths are 2.14 Å. In the fourth Ru site, Ru is bonded in a 8-coordinate geometry to four equivalent Ti and four equivalent B atoms. All Ru–B bond lengths are 2.19 Å. In the fifth Ru site, Ru is bonded in a distorted body-centered cubic geometry to four equivalent Ti and four equivalent B atoms. All Ru–B bond lengths are 2.19 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded in a body-centered cubic geometry to four equivalent Ru and four equivalent Rh atoms. All Fe–Rh bond lengths are 2.53 Å. In the second Fe site, Fe is bonded in a body-centered cubic geometry to eight Ru atoms. Rh is bonded in a 4-coordinate geometry to four Ti, two equivalent Fe, and two equivalent B atoms. Both Rh–B bond lengths are 2.16 Å. There are two inequivalent B sites. In the first B site, B is bonded in a 9-coordinate geometry to three Ti and six Ru atoms. In the second B site, B is bonded in a 6-coordinate geometry to three Ti, four Ru, and two equivalent Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ScGeRh by Materials Project

ScRhGe crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Sc is bonded in a 11-coordinate geometry to six equivalent Rh and five Ge atoms. There are two shorter (2.97 Å) and four longer (3.11 Å) Sc–Rh bond lengths. There are four shorter (2.79 Å) and one longer (2.81 Å) Sc–Ge bond lengths. Rh is bonded in a 12-coordinate geometry to six equivalent Sc, two equivalent Rh, and four Ge atoms. Both Rh–Rh bond lengths are 2.86 Å. There are two shorter (2.53 Å) and two longer (2.59 Å) Rh–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to six equivalent Sc and three equivalent Rh atoms. In the second Ge site, Ge is bonded in a 9-coordinate geometry to three equivalent Sc and six equivalent Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Economizing on Precious Metals in Three‐Way Catalysts: Thermally Stable and Highly Active Single‐Atom Rhodium on Ceria for NO Abatement under Dry and Industrially Relevant Conditions**

Abstract We show for the first time that atomically dispersed Rh cations on ceria, prepared by a high‐temperature atom‐trapping synthesis, are the active species for the (CO+NO) reaction. This provides a direct link with the organometallic homogeneous Rh I complexes capable of catalyzing the dry (CO+NO) reaction. The thermally stable Rh cations in 0.1 wt % Rh 1 /CeO 2 achieve full NO conversion with a turn‐over‐frequency (TOF) of around 330 h −1 per Rh atom at 120 °C. Under dry conditions, the main product above 100 °C is N 2 with N 2 O being the minor product. The presence of water promotes low‐temperature activity of 0.1 wt % Rh 1 /CeO 2 . In the wet stream, ammonia and nitrogen are the main products above 120 °C. The uniformity of Rh ions on the support, allows us to detect the intermediates of (CO+NO) reaction via IR measurements on Rh cations on zeolite and ceria. We also show that NH 3 formation correlates with the water gas shift (WGS) activity of the material and detect the formation of Rh hydride species spectroscopically.

Khivantsev, Konstantin↗
DOE OSTI2021

Long-Term Effects of Humidity on Stainless Steel Pitting in Sea Salt Exposures

Ground 304 stainless steel (SS) samples were exposed to sea salt particles at 35 °C and two relative humidity (RH) levels for durations ranging from 1 week to 2 years. For all exposure times, pit number density and total pit volume at 40% RH were observed to be considerably greater than those at 76% RH. Statistical analysis of distributions of pit populations for both RH conditions showed that pit number density and total pit volume increased rapidly at first but slowed as exposure time increased. Cross-hatched features were observed in the 40% RH pits while ellipsoidal, faceted pits were observed at 76% RH. Optical profilometry indicated that most pits were not hemispherical. X-ray tomography provided evidence of undercutting and fissures. Piecewise curve fitting modeled the 40% RH data closely, predicting that corrosion damage would eventually plateau. However, a similar treatment of the 76% RH data suggested that corrosion damage would continuously increase, which implied that the piecewise power-law fit was limited in its ability to model atmospheric corrosion generally. Based on these observations, the operative mechanisms determining long-term corrosion behavior were hypothesized to be different depending on the RH of exposure.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Multiphysics and Multiscale Modeling of Coupled Transport of Chloride Ions in Concrete

Chloride ions (Cl−)-induced corrosion is one of the main degradation mechanisms in reinforced concrete (RC) structures. In most situations, the degradation initiates with the transport of Cl− from the surface of the concrete towards the reinforcing steel. The accumulation of Cl− at the steel-concrete interface could initiate reinforcement corrosion once a threshold Cl− concentration is achieved. An accurate numerical model of the Cl− transport in concrete is required to predict the corrosion initiation in RC structures. However, existing numerical models lack a representation of the heterogenous concrete microstructure resulting from the varying environmental conditions and the indirect effect of time dependent temperature and relative humidity (RH) on the water adsorption and Cl− binding isotherms. In this study, a numerical model is developed to study the coupled transport of Cl− with heat, RH and oxygen (O2) into the concrete. The modeling of the concrete microstructure is performed using the Virtual Cement and Concrete Testing Laboratory (VCCTL) code developed by the U.S. National Institute of Standards and Technology (NIST). The concept of equivalent maturation time is utilized to eliminate the limitation of simulating concrete microstructure using VCCTL in specific environmental conditions such as adiabatic. Thus, a time-dependent concrete microstructure, which depends on the hydration reactions coupled with the temperature and RH of the environment, is achieved to study the Cl− transport. Additionally, Cl− binding isotherms, which are a function of the pH of the concrete pore solution, Cl− concentration, and weight fraction of mono-sulfate aluminate (AFm) and calcium-silicate-hydrate (C-S-H), obtained from an experimental study by the same authors are utilized to account for the Cl− binding of cement hydration products. The temperature dependent RH diffusion was considered to account for the transport of Cl− with moisture transport. The temperature and RH diffusion in the concrete domain, composite theory, and Cl− binding and water adsorption isotherms are used in combination, to estimate the ensuing Cl− diffusion field within the concrete. The coupled transport process of heat, RH, Cl−, and O2 is implemented in the Multiphysics Object-Oriented Simulation Environment (MOOSE) developed by the U.S. Idaho National Laboratory (INL). The model was verified and validated using data from multiple experimental studies with different concrete mixture proportions, curing durations, and environmental conditions. Additionally, a sensitivity analysis was performed to identify that the water-to-cement (w/c) ratio, the exposure duration, the boundary conditions: temperature, RH, surface Cl− concentration, Cl− diffusion coefficient in the capillary water, and the critical RH are the important parameters that govern the Cl− transport in RC structures. In a case study, the capabilities of the developed numerical model are demonstrated by studying the complex 2D diffusion of Cl− in a RC beam located in two different climatic regions: warm and humid weather in Galveston, Texas, and cold and dry weather in North Minnesota, Minnesota, subjected to time varying temperature, RH, and surface Cl− concentrations.

composite theory↗
DOE OSTI2020

Materials Data on Y2GeRh3 by Materials Project

Y2Rh3Ge crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Y is bonded in a 9-coordinate geometry to four equivalent Y, nine equivalent Rh, and three equivalent Ge atoms. There are one shorter (3.09 Å) and three longer (3.37 Å) Y–Y bond lengths. There are three shorter (2.93 Å) and six longer (3.21 Å) Y–Rh bond lengths. All Y–Ge bond lengths are 3.27 Å. Rh is bonded to six equivalent Y, four equivalent Rh, and two equivalent Ge atoms to form distorted RhY6Ge2Rh4 cuboctahedra that share corners with four equivalent GeY6Rh6 cuboctahedra, corners with fourteen equivalent RhY6Ge2Rh4 cuboctahedra, edges with six equivalent RhY6Ge2Rh4 cuboctahedra, faces with six equivalent GeY6Rh6 cuboctahedra, and faces with twelve equivalent RhY6Ge2Rh4 cuboctahedra. All Rh–Rh bond lengths are 2.81 Å. Both Rh–Ge bond lengths are 2.57 Å. Ge is bonded to six equivalent Y and six equivalent Rh atoms to form distorted GeY6Rh6 cuboctahedra that share corners with six equivalent GeY6Rh6 cuboctahedra, corners with twelve equivalent RhY6Ge2Rh4 cuboctahedra, edges with six equivalent GeY6Rh6 cuboctahedra, and faces with eighteen equivalent RhY6Ge2Rh4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ho2Ge2Rh by Materials Project

Ho2RhGe2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Ho sites. In the first Ho site, Ho is bonded in a 8-coordinate geometry to two equivalent Rh and six Ge atoms. Both Ho–Rh bond lengths are 3.05 Å. There are a spread of Ho–Ge bond distances ranging from 2.99–3.09 Å. In the second Ho site, Ho is bonded in a 11-coordinate geometry to four equivalent Rh and seven Ge atoms. There are a spread of Ho–Rh bond distances ranging from 3.01–3.25 Å. There are a spread of Ho–Ge bond distances ranging from 2.98–3.30 Å. Rh is bonded in a 10-coordinate geometry to six Ho and four Ge atoms. There are a spread of Rh–Ge bond distances ranging from 2.50–2.72 Å. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to seven Ho, one Rh, and one Ge atom. The Ge–Ge bond length is 2.63 Å. In the second Ge site, Ge is bonded in a 10-coordinate geometry to six Ho, three equivalent Rh, and one Ge atom. The Ge–Ge bond length is 2.69 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on VAsRh by Materials Project

RhVAs crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. V is bonded in a 3-coordinate geometry to six equivalent Rh and five equivalent As atoms. There are a spread of V–Rh bond distances ranging from 2.90–2.96 Å. There are a spread of V–As bond distances ranging from 2.53–2.82 Å. Rh is bonded in a 12-coordinate geometry to six equivalent V, two equivalent Rh, and four equivalent As atoms. Both Rh–Rh bond lengths are 2.81 Å. There are a spread of Rh–As bond distances ranging from 2.40–2.52 Å. As is bonded in a 9-coordinate geometry to five equivalent V and four equivalent Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SiRh2 by Materials Project

Rh2Si is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Rh sites. In the first Rh site, Rh is bonded to four equivalent Si atoms to form a mixture of distorted edge and corner-sharing RhSi4 tetrahedra. There are a spread of Rh–Si bond distances ranging from 2.42–2.47 Å. In the second Rh site, Rh is bonded in a 3-coordinate geometry to three equivalent Si atoms. There are one shorter (2.49 Å) and two longer (2.50 Å) Rh–Si bond lengths. Si is bonded in a 7-coordinate geometry to seven Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La2InRh2 by Materials Project

La2Rh2In crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. La is bonded in a 6-coordinate geometry to six equivalent Rh and four equivalent In atoms. There are two shorter (2.92 Å) and four longer (3.10 Å) La–Rh bond lengths. All La–In bond lengths are 3.49 Å. Rh is bonded in a 2-coordinate geometry to six equivalent La, one Rh, and two equivalent In atoms. The Rh–Rh bond length is 2.91 Å. Both Rh–In bond lengths are 3.01 Å. In is bonded to eight equivalent La and four equivalent Rh atoms to form a mixture of corner and face-sharing InLa8Rh4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SbRh2 by Materials Project

Rh2Sb is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Rh sites. In the first Rh site, Rh is bonded in a 3-coordinate geometry to five equivalent Sb atoms. There are a spread of Rh–Sb bond distances ranging from 2.68–2.99 Å. In the second Rh site, Rh is bonded to five equivalent Sb atoms to form a mixture of distorted edge and corner-sharing RhSb5 tetrahedra. There are a spread of Rh–Sb bond distances ranging from 2.61–3.27 Å. Sb is bonded in a 10-coordinate geometry to ten Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BRh2 by Materials Project

Rh2B is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Rh sites. In the first Rh site, Rh is bonded in a distorted trigonal non-coplanar geometry to three equivalent B atoms. There are one shorter (2.09 Å) and two longer (2.34 Å) Rh–B bond lengths. In the second Rh site, Rh is bonded in a 4-coordinate geometry to four equivalent B atoms. There are a spread of Rh–B bond distances ranging from 2.12–2.47 Å. B is bonded in a 7-coordinate geometry to seven Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ce3(GeRh)2 by Materials Project

Ce3Rh2Ge2 crystallizes in the orthorhombic Pbcm space group. The structure is three-dimensional. there are two inequivalent Ce sites. In the first Ce site, Ce is bonded in a 9-coordinate geometry to four equivalent Rh and five Ge atoms. There are two shorter (3.08 Å) and two longer (3.10 Å) Ce–Rh bond lengths. There are a spread of Ce–Ge bond distances ranging from 3.03–3.34 Å. In the second Ce site, Ce is bonded in a 8-coordinate geometry to four equivalent Rh and five Ge atoms. There are a spread of Ce–Rh bond distances ranging from 2.86–3.22 Å. There are a spread of Ce–Ge bond distances ranging from 3.10–3.40 Å. Rh is bonded in a 9-coordinate geometry to six Ce and three Ge atoms. There are a spread of Rh–Ge bond distances ranging from 2.56–2.68 Å. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 12-coordinate geometry to eight Ce and four equivalent Rh atoms. In the second Ge site, Ge is bonded in a 9-coordinate geometry to seven Ce and two equivalent Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GeRh2 by Materials Project

Rh2Ge is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Rh sites. In the first Rh site, Rh is bonded to five equivalent Ge atoms to form a mixture of distorted edge and corner-sharing RhGe5 tetrahedra. There are a spread of Rh–Ge bond distances ranging from 2.50–3.06 Å. In the second Rh site, Rh is bonded in a 3-coordinate geometry to five equivalent Ge atoms. There are a spread of Rh–Ge bond distances ranging from 2.55–2.88 Å. Ge is bonded in a 10-coordinate geometry to ten Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on P2Rh3 by Materials Project

Rh3P2 crystallizes in the tetragonal P-4m2 space group. The structure is three-dimensional. there are two inequivalent Rh sites. In the first Rh site, Rh is bonded in a 4-coordinate geometry to four equivalent P atoms. All Rh–P bond lengths are 2.33 Å. In the second Rh site, Rh is bonded in a 5-coordinate geometry to five equivalent P atoms. There are one shorter (2.36 Å) and four longer (2.48 Å) Rh–P bond lengths. P is bonded to seven Rh atoms to form a mixture of distorted edge, corner, and face-sharing PRh7 pentagonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Y2Si2Rh by Materials Project

Y2RhSi2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Y sites. In the first Y site, Y is bonded in a 2-coordinate geometry to four equivalent Rh and six Si atoms. There are a spread of Y–Rh bond distances ranging from 3.06–3.15 Å. There are a spread of Y–Si bond distances ranging from 2.92–3.07 Å. In the second Y site, Y is bonded in a 6-coordinate geometry to two equivalent Rh and six Si atoms. Both Y–Rh bond lengths are 3.26 Å. There are a spread of Y–Si bond distances ranging from 2.90–3.16 Å. Rh is bonded in a 4-coordinate geometry to six Y and four Si atoms. There are a spread of Rh–Si bond distances ranging from 2.45–2.59 Å. There are two inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to five Y, three equivalent Rh, and one Si atom. The Si–Si bond length is 2.62 Å. In the second Si site, Si is bonded in a 9-coordinate geometry to seven Y, one Rh, and one Si atom. The Si–Si bond length is 2.56 Å.

36 MATERIALS SCIENCE↗