Search NASA⌕ Search

SEARCH · Search NASA

Results for “ROUTING”

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 685 records · Page 38
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

The hydrogen-containing bronzes H 0.23 WO 3 and H 0.10 ReO 3 synthesized via a polymer route

We report the synthesis of two hydrogen-containing perovskite-type bronzes H 0.23 WO 3 and H 0.10 ReO 3 utilizing an unconventional solid-state synthetic approach, involving the use of the polymer Poly(vinylidene fluoride) (CH 2 CF 2 ) n. Powder neutron diffraction at ambient temperature shows that H 0.23 WO 3 crystallizes in a tetragonal symmetry distortion of the simple perovskite structure (space group P4/nmm), with lattice parameters a = 5.2279(2) Å, and c =3.8763(1) Å. H 0.10 ReO 3 , in contrast, crystallizes in a monoclinic distortion of a simple cubic perovskite (space group P2/m), with lattice parameters a = 5.3125(1) Å, b = 5.3155(3) Å, c = 3.7045(3) Å, and γ = 90.43(1)°. Both H 0.23 WO 3 and H 0.10 ReO 3 exhibit intrinsically diamagnetic behavior, with low temperature paramagnetic upturns and no signs of bulk superconductivity down to 0.35 K.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Refueling infrastructure planning in intercity networks considering route choice and travel time delay for mixed fleet of electric and conventional vehicles

The range anxiety has been a major factor that affects the market acceptance of electric vehicles. Even with the recent development of battery technologies, a lack of charging stations and range anxiety are still significant concerns, specifically for intercity trips. This calls for more investments in building charging stations and advancing battery technologies to increase the market share of electric vehicles and improve sustainability. This study suggests a configuration for plug-in electric vehicle charging infrastructure to support long-distance intercity trips of electric vehicles at the network level. A model is proposed to minimize the total system cost including infrastructure investment (building charging stations/spots) and travel time delays (charging time, waiting time in the queue, and detour time to access charging stations). This study fills existing gaps in the literature by capturing realistic patterns of travel demand and considering flow-dependent charging delays at charging stations. Furthermore, the proposed model, which is formulated as a mixed-integer program with nonlinear constraints, solves the optimization problem at the network level. At the network level, impacts of charging station locations on the traffic assignment problem with a mixed fleet of electric and conventional vehicles need to be considered. To this end, a traffic assignment module is integrated with a simulated annealing algorithm. The numerical experiments show a satisfactory application of the model for a full-scale case study (intercity network in Michigan). The solution quality and efficiency of the proposed solution algorithm are evaluated against those of an enumeration approach for a small case study. The results suggest that even for the current market share and charging stations’ setting, a significant investment is needed to support intercity trips without range anxiety issues and with acceptable delays. Additionally, through sensitivity analyses, the required infrastructure and battery investments to support intercity trips with acceptable delays are established for hypothetical increased market shares and battery size in the future.

42 ENGINEERING↗
DOE OSTI2015

Evaluating Global Streamflow Simulations by a Physically-based Routing Model Coupled with the Community Land Model

Accurately simulating hydrological processes such as streamflow is important in land surface modeling because they can influence other land surface processes, such as carbon cycle dynamics, through various interaction pathways. This study aims to evaluate the global application of a recently developed Model for Scale Adaptive River Transport (MOSART)coupled with theCommunity Land Model, version 4 (CLM4). To support the global implementation of MOSART, a comprehensive global hydrography dataset has been derived at multiple resolutions from different sources. The simulated runoff fields are first evaluated against the composite runoff map from theGlobal RunoffData Centre (GRDC). The simulated streamflow is then shown to reproduce reasonably well the observed daily andmonthly streamflow at over 1600 of the world’smajor river stations in terms of annual, seasonal, and daily flow statistics. The impacts of model structure complexity are evaluated, and results show that the spatial and temporal variability of river velocity simulated byMOSART is necessary for capturing streamflow seasonality and annual maximum flood. Other sources of the simulation bias include uncertainties in the atmospheric forcing, as revealed by simulations driven by four different climate datasets, and human influences, based on a classification framework that quantifies the impact levels of large dams on the streamflow worldwide.

global evaluation, routing model, community land m↗
DOE OSTI2018

Growth and Isolation of Large Area Boron-Doped Nanocrystalline Diamond Sheets: A Route toward Diamond-on-Graphene Heterojunction

Many material device applications would benefit from thin diamond coatings, but current growth techniques, such as chemical vapor deposition (CVD) or atomic layer deposition require high substrate and gas-phase temperatures that would destroy the device being coated. The development of freestanding, thin boron-doped diamond nanosheets grown on tantalum foil substrates via microwave plasma-assisted CVD is reported. These diamond sheets (measuring up to 4 × 5 mm in planar area, and 300–600 nm in thickness) are removed from the substrate using mechanical exfoliation and then transferred to other substrates, including Si/SiO 2 and graphene. The electronic properties of the resulting diamond nanosheets and their dependence on the free-standing growth, the mechanical exfoliation and transfer processes, and ultimately on their composition are characterized. To support this, a prototypical diamond nanosheet–graphene field effect transistor-like (DNGfet) device is developed and its electronic transport properties are studied as a function of temperature. The resulting DNGfet device exhibits thermally activated transport (thermionic conductance) above 50 K. Below 50 K a transition to variable range hopping is observed. Finally, these findings demonstrate the first step towards a low-temperature diamond-based transistor.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Decoding Li + /Na + Exchange Route Toward High-Performance Mn-Based Layered Cathodes for Li-Ion Batteries

Li + /Na + exchange has been extensively explored as an effective method to prepare high-performance Mn-based layered cathodes for Li-ion batteries, since the first report in 1996 by P. G. Bruce (Nature, 1996. 381, 499–500). Understanding the detailed structural changes during the ion-exchange process is crucial to implement the synthetic control of high-performance layered Mn-based cathodes, but less studied. Herein, in situ synchrotron X-ray diffraction, density functional theory calculations, and electrochemical tests are combined to conduct the systemic studies into the structural changes during the ion-exchange process of an Mn-only layered cathode O3-type Li 0.67 [Li 0.22 Mn 0.78 ]O 2 (LLMO) from the corresponding counterpart P3-type Na 0.67 [Li 0.22 Mn 0.78 ]O 2 (NLMO). The temperature-resolved observations combined with theoretical calculations reveal that the Li + /Na + exchange is favorable thermodynamically and composited with two tandem topotactic phase transitions: 1) from NLMO to a layered intermediate through ≈60% of Li + /Na + exchange. 2) then to the final layered product LLMO through further Li insertion. Moreover, the intermediate-dominate composite is obtained by slowing down the exchange kinetics below room temperature, showing better electrochemical performance than LLMO obtained by the traditional molten-salt method. Finally, the findings provide guides for the synthetic control of high-performance Mn-based cathodes under mild conditions.

25 ENERGY STORAGE↗
DOE OSTI2017

Re Doping in 2D Transition Metal Dichalcogenides as a New Route to Tailor Structural Phases and Induced Magnetism

Alloying in 2D results in the development of new, diverse, and versatile systems with prospects in bandgap engineering, catalysis, and energy storage. Tailoring structural phase transitions using alloying is a novel idea with implications in designing all 2D device architecture as the structural phases in 2D materials such as transition metal dichalcogenides are correlated with electronic phases. In this paper, this study develops a new growth strategy employing chemical vapor deposition to grow monolayer 2D alloys of Re-doped MoSe 2 with show composition tunable structural phase variations. The compositions where the phase transition is observed agree well with the theoretical predictions for these 2D systems. Finally, it is also shown that in addition to the predicted new electronic phases, these systems also provide opportunities to study novel phenomena such as magnetism which broadens the range of their applications.

2D materials↗
DOE OSTI2020

Water-Surface Drag Coating: A New Route Toward High-Quality Conjugated Small-Molecule Thin Films with Enhanced Charge Transport Properties

Electronic properties of organic semiconductor (OSC) thin films are largely determined by their morphologies and crystallinities. However, solution-processed conjugated small-molecule OSC thin films usually exhibit abundant grain boundaries and impure grain orientations because of complex fluid dynamics during solution coating. Here, a novel methodology, water-surface drag coating, is demonstrated to fabricate high-quality OSC thin films with greatly enhanced charge transport properties. This method utilizes the water surface to alter the evaporation dynamics of solution to enlarge the grain size, and a unique drag-coating process to achieve the unidirectional growth of organic crystals. Furthermore, using 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene (Dif-TES-ADT) as an example, thin films with millimeter-sized single-crystal domains and pure crystallographic orientations are achieved, revealing a significant enhancement (4.7 times) of carrier mobility. More importantly, the resulting film can be directly transferred onto any desired flexible substrates, and flexible transistors based on the Dif-TES-ADT thin films show a mobility as high as 16.1 cm 2 V -1 s -1 , which represents the highest mobility value for the flexible transistors reported thus far. The method is general for the growth of various high-quality OSC thin films, thus opening up opportunities for high-performance organic flexible electronics.

36 MATERIALS SCIENCE↗
DOE OSTI2025

A Simple Route for Open Fluidic Devices with Particle Walls

Open fluidics, allowing liquid in a flow channel to interact with the external environment, is a revolutionary concept. However, fabricating a highly stable open fluidic device of arbitrary complexity, while maintaining reconfigurability, is still a challenge. This is achieved by the use of a patterned substrate and liquids that are covered with functional, readily available hydrophobic particles, providing great flexibility in the construction and use of open fluidic structures. Decorated with a coating of modified carbon nanotubes (CNTs) to encapsulate the fluids, the study capitalizes on the photothermal characteristics of CNTs to fabricate a device to probe the effects of temperature on tumor chemotherapy. The strategy substantially increases the availability and potential use of open fluidic devices.

Liu, Heng↗