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Results for “PLATES”
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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A novel approach to modeling plate deformations in fluid–structure interactions
Not Available
Optimizing the position resolution of a Z-stack microchannel plate resistive anode detector for low intensity signals
A method for achieving good position resolution of low-intensity electron signals using a microchannel plate resistive anode detector is demonstrated. Electron events at a rate of 7 counts s{sup −1} are detected using a Z-stack microchannel plate. The dependence of position resolution on both the distance and the potential difference between the microchannel plate and resistive anode is investigated. Using standard commercial electronics, a measured position resolution of 170 μm (FWHM) is obtained, which corresponds to an intrinsic resolution of 157 μm (FWHM)
Interim Report on Mixing During the Casting of LEU-10Mo Plates in the Triple Plate Molds
LEU-10%Mo castings are commonly produced by down blending unalloyed HEU with a DU-12.7%Mo master-alloy. This work uses process modeling to provide insight into the mixing of the unalloyed uranium and U-Mo master alloy during melting and mold filling of a triple plate casting. Two different sets of situations are considered: (1) mixing during mold filling from a compositionally stratified crucible and (2) convective mixing of a compositionally stratified crucible during mold heating. The mold filling simulations are performed on the original Y-12 triple plate mold and the horizontal triple plate mold.
Carbon cladded composite flow field plate, bipolar plate and fuel cell
The present invention provides a carbon-cladded composite composition for use as a fuel cell flow field plate or bipolar plate. In one preferred embodiment, the composition comprises a core composite layer sandwiched between two clad layers, wherein (a) the clad layer comprises a conductive carbon or graphite material (e.g., carbon nano-tubes, nano-scaled graphene plates, graphitic nano-fibers, and fine graphite particles); (b) the core composite layer comprises a matrix resin and a conductive filler present in a sufficient quantity to render the composite layer electrically conductive with an electrical conductivity no less than 1 S/cm (preferably no less than 100 S/cm); and (c) the composition has a planar outer surface on each clad side having formed therein a fluid flow channel.
Three-dimensional simulation of rivulet and film flows over an inclined plate: Effects of solvent properties and contact angle
This is the paper we drafted based on CCSI Task 3 work on wetted area prediction with volume of fluids method.
Evaluation of residual stresses in isothermal friction stir welded 304L stainless steel plates
Friction stir welding was performed on 304L SS plates in order to heal simulated cracks created by electrical discharge machining. Two different tool temperatures (825 and 725 °C) were chosen for this study. Both neutron diffraction and X-ray diffraction techniques were employed to evaluate the residual stresses along two orthogonal reference directions, longitudinal (syy) and transverse (sxx). The former technique was also used to measure residual stresses at various depths. It was found that, at 1 mm depth from the top surface inside the stir zone (SZ), the longitudinal component was tensile in nature while the transverse component was compressive. The nature and magnitude of the residual stress fields, and the position of the peak residual stresses were found to vary with the weld depth. The SZ of the 725 °C weld exhibited higher peak stress than 825 °C weld mainly due to a lack of stress relief at the lower temperature.
Mechanistic understanding of electrochemical plating and stripping of metal electrodes
Mechanisms driving the evolution of the metal electrode interface during plating, stripping and formation of dead metal.
Requirements for Enabling Extreme Fast Charging of High Energy Density Li-Ion Cells while Avoiding Lithium Plating
To improve electric vehicle market acceptance, the charge time of their batteries should be reduced to 10–15 minutes. However, achieving 4C to 6C charge rates with today’s batteries is only possible for cells with thin electrodes coming at the expense of low energy density and high battery manufacturing cost. An electrochemical model is validated versus high rate charge data for cells with several loadings. The model elucidates that the main limitations for high energy density cells are poor electrolyte transport resulting in salt depletion within the anode and Li plating at the graphite/separator interface. Next, the model is used to understand what future electrode and electrolyte properties can help enable 4C and 6C charging. Ideally, future electrolytes would be identified with 2X conductivity, 3–4X diffusivity, and transference number of 0.5–0.6. Alternatively charging at elevated temperatures enhances electrolyte transport by 1.5X conductivity and 2–3X diffusivity with a negligible effect on transference number. Another effective strategy to enable 4C and 6C charging is reducing electrode tortuosity. Conversely, increasing electrode porosity and negative/positive ratio are ineffective strategies to improve fast charge capability.
Design and fabrication of prototype 6×6 cm 2 microchannel plate photodetector with bialkali photocathode for fast timing applications
Planar microchannel plate-based photodetector with bialkali photocathode is capable of fast and accurate time and position resolutions. A new 6 cm x 6 cm photodetector production facility was designed and built at Argonne National Laboratory. Small form-factor MCP-based photodetectors completely constructed of glass were designed and prototypes were successfully fabricated. Knudsen effusion cells were incorporated in the photocathode growth chamber to achieve uniform and high quantum efficiency hotocathodes. The thin film uniformity distribution was simulated and measured for an antimony film deposition, showing uniformity of better than 10%. Several prototype devices with bialkali photocathodes have been fabricated with the described system and their characteristics were evaluated in the large signal (multi-PE) limit. A typical prototype device exhibits time-of-flight resolution of ~ 27 psec and differential time resolution of ~ 9 psec, corresponding to spatial resolution of ~ 0.65 mm.
Fast-timing microchannel plate photodetectors: design, fabrication and characterization
We report a detailed design, fabrication, and characterization of 6 x 6 cm(2) fast timing photodetectors based on next-generation microchannel plates (MCPs). The whole assembly is made of low-cost borosilicate glass materials and hermetically sealed with a bialkali photocathode in a vacuum. The flexible photodetector design provides the potential of modifying individual components as well as the entire configuration to fit for different applications. A series of prototype MCP-photodetectors were fabricated following a step-by-step process including functionalization of glass capillary array through atomic layer deposition, MCP baking and scrubbing, photocathode deposition, and hermetic thermo-compression sealing. The prototype MCP-photodetectors exhibit electron gains well beyond 107 level with good relative uniformity. An excellent rise time of 439 ps, timing distribution root-mean-square at a single photoelectron mode of 105 ps, a timing resolution of 20 ps, and magnetic field tolerance up to 1.3 T were achieved for a photodetector with 10 mu m pore size MCPs, comparing to that of 536 ps, 205 ps, 63 ps, and 0.7 T for the one with 20 mu m pore size MCPs. Published under license by AIP Publishing.
High-pressure, high-temperature equations of state using nanofabricated controlled-geometry Ni/SiO[subscript 2]/Ni double hot-plate samples
Abstract not provided
Lithium loss, resistance growth, electrode expansion, gas evolution, and Li plating: Analyzing performance and failure of commercial large-format NMC-Gr lithium-ion pouch cells
Not Available
Experimental Insights into the Coupling of Methane Combustion and Steam Reforming in a Catalytic Plate Reactor in Transient Mode
The microstructured reactor concept is very promising technology to develop a compact reformer for distributed hydrogen generation. In this work, a catalytic plate reactor (CPR) is developed and investigated for the coupling of methane combustion (MC) and methane steam reforming (MSR) over Pt/Al 2 O 3 -coated microchannels in cocurrent and counter-current modes in transient experiments during start-up. A three-dimensional (3D) computational fluid dynamics (CFD) simulation shows uniform velocity and pressure distribution profiles in microchannels. For a channel velocity from 5.1 to 57.3 m/s in the combustor, the oxidation of methane is complete and self-sustainable without explosion, blow-off, or extinction; nevertheless, flashbacks are observed in counter-current mode. In the reformer, the maximum methane conversion is 84.9% in cocurrent mode, slightly higher than that of 80.2% in counter-current mode at a residence time of 33 ms, but at the cost of three times higher energy input in the combustor operating at ~1000 °C. Nitric oxide (NO) is not identified in combustion products, but nitrous oxide (N 2 O) is a function of coupling mode and forms significantly in cocurrent mode. Furthermore, this research would be helpful to establish the start-up strategy and environmental impact of compact reformers on a small scale.
Fresnel zone plate point spread function approximation for zeroth order mitigation in millimetric field of view x-ray imaging
High spatial and temporal resolution x-ray radiography images are required at the National Ignition Facility (NIF) for high-energy density experiments. One technique that is in development to achieve the required resolution uses Fresnel zone plate (FZP) optics to image an object that is backlit by an x-ray source. The multiple FZP diffraction orders do not focus on the same plane, which increases the background and reduces the contrast. Understanding the point spread function of the different diffraction orders will allow the prediction of the expected background using simulations. We find that the two-dimensional point spread function of the FZP can be approximated by the addition of a sharp Gaussian with a disk. This allowed for the estimation of the background in NIF experimental images of Rayleigh–Taylor spikes and their interpretation. An alternative design of FZP is discussed to allow the inclusion of a zeroth order blocker to reduce the background.
Analytical theory of coherent synchrotron radiation wakefield of short bunches shielded by conducting parallel plates
Not Available
Atomic layer deposition of alternative glass microchannel plates
The technique of atomic layer deposition (ALD) has enabled the development of alternative glass microchannel plates (MCPs) with independently tunable resistive and emissive layers, resulting in excellent thickness uniformity across the large area (20 × 20 cm), high aspect ratio (60:1 L/d) glass substrates. Furthermore, the use of ALD to deposit functional layers allows the optimal substrate material to be selected, such as borosilicate glass, which has many benefits compared to the lead-oxide glass used in conventional MCPs, including increased stability and lifetime, low background noise, mechanical robustness, and larger area (at present up to 400 cm{sup 2}). Resistively stable, high gain MCPs are demonstrated due to the deposition of uniform ALD resistive and emissive layers on alternative glass microcapillary substrates. The MCP performance characteristics reported include increased stability and lifetime, low background noise (0.04 events cm{sup −2} s{sup −1}), and low gain variation (±5%)