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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.
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Implicit filtered P{sub N} for high-energy density thermal radiation transport using discontinuous Galerkin finite elements
In this work, we provide a fully-implicit implementation of the time-dependent, filtered spherical harmonics (FP{sub N}) equations for non-linear, thermal radiative transfer. We investigate local filtering strategies and analyze the effect of the filter on the conditioning of the system, showing in particular that the filter improves the convergence properties of the iterative solver. We also investigate numerically the rigorous error estimates derived in the linear setting, to determine whether they hold also for the non-linear case. Finally, we simulate a standard test problem on an unstructured mesh and make comparisons with implicit Monte Carlo (IMC) calculations.
Influence of water content on alkali metal chloride transport in cross-linked Poly(ethylene glycol) diacrylate.2. Ion diffusion
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Noninvasive Surface Coverage Determination of Chemically Modified Conical Nanopores that Rectify Ion Transport
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α-Particle Detection and Charge Transport Characteristics in the A 3 M 2 I 9 Defect Perovskites (A = Cs, Rb; M = Bi, Sb)
Here, we have investigated the defect perovskites A 3 M 2 I 9 (A = Cs, Rb; M = Bi, Sb) as materials for radiation detection. The phase purity of Bridgman-grown A 3 M 2 I 9 single crystals was confirmed via high-resolution synchrotron X-ray diffraction, while density functional theory calculations (DFT) show surprisingly dispersive bands in the out-of-plane direction for these layered materials, with low effective masses for both holes and electrons. Accordingly, each of the four A 3 M 2 I 9 defect perovskites showed response to 241 Am α-particle irradiation for hole and electron electrode configurations, a remarkable ambipolar response that resembles the 3D halide perovskites. The electron response spectra were used to estimate the mobility–lifetime product (μτ) e for electrons in these materials, with Rb 3 Bi 2 I 9 showing the lowest (μτ) e value of 1.7 × 10 – 6 cm 2 V –1 and Cs 3 Bi 2 I 9 the highest (μτ) e of 5.4 × 10 –5 cm 2 V –1 . The rise time of the α-particle-generated pulse was used to estimate the electron mobility μ e of the A 3 M 2 I 9 defect perovskites, which ranged from 0.32 cm 2 V –1 s–1 for Rb 3 Sb 2 I 9 to 4.3 cm 2 V –1 s –1 in Cs 3 Bi 2 I 9 . Similar analysis of the hole response spectra yielded (μτ) h values for each A 3 M 2 I 9 compound, with Cs 3 Bi 2 I 9 again showing the highest (μτ) h value of 1.8 × 10 –5 cm 2 V –1 , while Rb 3 Bi 2 I 9 showed the lowest (μτ) h with 2.0 × 10 –6 cm 2 V –1 . Rise time analysis gave hole mobilities ranging from 1.7 cm 2 V –1 s –1 for Cs 3 Bi 2 I 9 to 0.14 cm 2 V –1 s –1 for Cs 3 Sb 2 I 9 . Comparing the experimental electron and hole mobilities to the effective masses obtained from DFT calculations revealed sizable discrepancies, possibly indicating self-trapping of charge carriers due to electron–phonon interactions. The α-particle response of the A 3 M 2 I 9 defect perovskites demonstrates their potential as semiconductor radiation detectors, with Cs 3 Bi 2 I 9 and Cs 3 Sb 2 I 9 showing the most promise.
Mimicking the Electron Transport Chain and Active Site of [FeFe] Hydrogenases in One Metal–Organic Framework: Factors That Influence Charge Transport
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Band bending in conjugated polymer films: role of morphology and implications for bulk charge transport characteristics
The band bending effect depends on the morphology of the conjugated polymer as studied by Kelvin probe force microscopy.
Oligomerization of ethanol-derived propene and isobutene mixtures to transportation fuels: catalyst and process considerations
An important activity/selectivity trade-off occurs at increased olefin oligomerization temperatures. Jet-range product decreases and paraffin formation increases at high oligomerization temperatures.
Time- and momentum-resolved probe of heat transport in photo-excited bismuth
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Transport properties of cubic crystalline Ge 2 Sb 2 Te 5 : a potential low-temperature thermoelectric material.
Ge 2 Sb 2 Te 5 (GST) has been widely used as a popular phase change material. In this study, we show that it exhibits high Seebeck coe cients 200 - 300 μV/K in its cubic crystalline phase (c-GST) at remarkably high p-type doping levels of 1 10 19 - 6 10 19 cm -3 at room temperature. More importantly, at low temperature (T = 200 K), the Seebeck coe cient was found to exceed 200 μV/K for a doping range 1 10 19 - 3.5 10 19 cm -3 . Given that the lattice thermal conductivity in this phase has already been measured to be extremely low ( 0.7 W/m-K at 300 K), our results suggest the possibility of using c-GST as a low-temperature thermoelectric material.
Electrostatic lock in the transport cycle of the multidrug resistance transporter EmrE
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Investigation of energy transport in DIII-D High- β P EAST-demonstration discharges with the TGLF turbulent and NEO neoclassical transport models
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High-temperature charge and thermal transport properties of the n -type thermoelectric material PbSe
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Trends in electrical transport of p -type skutterudites R Fe 4 Sb 12 ( R = Na, K, Ca, Sr, Ba, La, Ce, Pr, Yb) from first-principles calculations and Boltzmann transport theory
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