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At least 127 records · Page 7

Calculations Document

Figure 1 shows a simplified model schematic of the Tetracage target design. In this figure the green lines represent the Tetracage yarns, which consist of two parallel yarns on the top and two parallel yarns on the bottom with the pairs in a cross hatched pattern. For simplicity, as we are only considering vertical forces, we will perform calculations without consideration for the two pairs of yarns being perpendicular to each other. Also worth noting is the model shows the yarns extending directly to the capsule then closely hugging it – in reality, the yarns behave as you would expect where they hug the capsule only as much as the geometry of their deflection allows, similarly to if you held a tennis ball with a pair of parallel strings anchored at opposing ends. The dashed black lines show the path the yarns take straight across from slot glue point to slot glue point before the target is closed and the capsule deforms them. The variable r corresponds to the capsule outer radius. The variable L corresponds to the hohlraum inner radius. The variable a corresponds to the yarn offset from the center of the diagnostic band. The variable d corresponds to the wire deflection vertically.

42 ENGINEERING↗

Parametric model-order-reduction development for unsteady convection

A time-averaged error indicator with POD- h Greedy is developed to drive parametric model order reduction (pMOR) for 2D unsteady natural convection in a high-aspect ratio slot parameterized with the Prandtl number, Rayleigh number, and slot angle with respect to the gravity. The error indicator is extended to accommodate the energy equation and Leray regularization. Despite being two-dimensional and laminar, the target flow regime presents several challenges: 1) there is a bifurcation in the angle parameter space; 2) the solution can be multivalued, even at steady state; and 3) the solution exhibits spatio-temporal chaos at several points in the parameter space. The authors explore several reduced-order models (ROMs) and demonstrate that Leray-regularized Galerkin ROMs provide a robust solution approach for this class of flows. They further demonstrate that error-indicated pMOR can efficiently predict several QOIs, such as mean flow, mean Nusselt number and mean turbulent kinetic energy, even in the presence of a bifurcation. Finally, they show that spatio-temporal chaos can lead to lack of reproducibility in both the full-order model and the reduced-order model and that the variance in the full-order model provides a lower bound on the pMOR error in these cases.

leray regularization↗

Tracking Robot Location for Non-Destructive Evaluation of Double-Shell Tanks

(1) Background: Non-destructive evaluation of double-shell nuclear-waste storage tanks at the U.S. Department of Energy’s Hanford site requires a robot to navigate a network of air slots in the confined space between primary and secondary tanks. Situational awareness, data collection, and data interpretation require continuous tracking of the robot’s location. (2) Methods: Robot location is continuously monitored using video image analysis for short distances and laser ranging for absolute location. (3) Results: The technique was demonstrated in our laboratory using a mockup of air slot and robot. (4) Conclusions: Location tracking and display provide decision support to inspectors and lay the groundwork for automated data collection.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Thermal Frequency Drift of 3D Printed Microwave Components

Fabrication of microwave slot array antennas and waveguide bandpass and notch filters using 3D printing has significant advantages in terms of speed and cost even for parts with high mechanical complexity. One disadvantage of Stereolithography (SLA) 3D printed, copper plated microwave components is that some SLA resins have a high Coefficient of Thermal Expansion (CTE), quoted in micrometers per meter per degree or 10 -6 per degree. Compared to typically used metals such as aluminum (CTE 24 × 10 -6 ·K -1 ) and copper (CTE 17 × 10 -6 ·K -1 ), SLA resin can have CTE above 100 × 10 -6 ·K -1 . Resonant structures experience significant frequency drift with temperature changes on the order of 10–50 °C. The issue of 3D printed microwave structures changing frequency characteristics significantly with temperature shift has not been addressed or reviewed in current literature. We measured and simulated the effect of temperature change on a slot array, cavity notch filters, and post loaded waveguide bandpass filters. We tested several types of SLA resin, different plating techniques, and also Direct Metal Laser Sintering (DMLS) and Binder Infusion metal 3D printing. Performance as a function of temperature is presented for these alternatives.

three-dimensional printing↗

A High Gain Lens-Coupled On-Chip Antenna Module for Miniature-Sized Millimeter-Wave Wireless Transceivers

This paper presents high gain and compact Transmit/Receive (TX/RX) integrated antennas in a standard BiCMOS 130nm technology for millimeter-scale millimeter-wave (mm-wave) applications, including high data rate radios and high resolution radars. The proposed TX/RX antenna module utilizes an integrated dipole antenna for the receiver and a slot antenna for the transmitter, placed orthogonally. The achieved gain and radiation efficiency are 5.7dBi and 41.3% for the slot antenna, respectively, and 6dBi and 39% for the dipole antenna. The link budget is improved by 16dB by optimization on the geometry aswell as application of a high resistivity hemispheric silicon dielectric lens.

Engineering↗

Switchable rocker arm

A rocker arm includes an outer arm defining a lock pin bore which is centered about a lock pin bore axis and an inner arm which selectively pivots relative to the outer arm about a pivot axis which is parallel to the lock pin bore axis. The inner arm includes a protrusion which defines an inner arm stop surface which is planar. A lock pin is disposed within the lock pin bore, the lock pin having a lock pin slot extending there into and also having a lock pin stop surface which is planar. The lock pin is displaced within the lock pin bore between a coupled position in which the lock pin stop surface is aligned with the inner arm stop surface and a decoupled position in which the lock pin slot is aligned with the protrusion.

42 ENGINEERING↗

Validation and Parametric Investigations Using a Lumped Thermal Parameter Model of an Internal Permanent Magnet Motor: Preprint

One of the key challenges for the electric vehicle industry is to develop high-power-density electric motors. Achieving higher power density requires efficient heat removal from inside the motor. In order to improve thermal management, a multi-physics modeling framework that is able to accurately predict the behavior of the motor, while being computationally efficient, is essential. This paper first presents a detailed validation of a Lumped Parameter Thermal Network (LPTN) model of an Internal Permanent Magnet (IPM) synchronous motor within the commercially available Motor-CAD® modeling environment. The IPM motor’s stator is studied at steady state, and winding losses are generated by a constant DC current. The validation is based on temperature comparison with experimental data and with more detailed Finite Element Analysis (FEA). All critical input parameters of the LPTN are considered in detail for each layer of the stator, especially the contact resistances between the impregnation, liner, laminations and housing. Finally, a sensitivity analysis for each of the critical input parameters is provided. A maximum difference of 4% - for the highest temperature in the slot windings and the end windings - was found between the LPTN and the experimental data. Comparing the results from the LPTN and the FEA model, the maximum difference was 2% for the highest temperature in the slot windings and end windings. As for the LTPN sensitivity analysis, the thermal parameter with the highest sensitivity was found to be the liner-to-lamination contact resistance. The latter is often ignored in the literature, whereas its impact on temperature rise was found to be more significant than any other contact resistance within the stator.

ADVANCED PROPULSION SYSTEMS↗

Optical fiber receptacle cover

A cover for partially covering and protecting cables plugged into a receptacle is provided. The receptacle includes a face plate with a first hole through which a first fastener secures the face plate to a face of the receptacle. The cover comprises a plurality of walls at least partially defining a hollow chamber, a slot adjacent to the chamber and configured to receive the face plate when the cover is slid over the face plate, an opening that leads to the chamber and the slot, and a first channel extending partially through the chamber and configured to provide access to the fastener.

42 ENGINEERING↗

Vertically oriented seal system for gas turbine vanes

A seal system for a gas turbine vane includes a first seal layer and an optional second seal layer. Each first seal layer includes multiple seal segments, each of which includes a first leg, a second leg, and an intermediate portion between the first leg and the second leg. Each adjacent pair of seal segments of the first seal is separated by a gap. The seal segments define a substantially complete perimeter of a seal slot in which the first seal is installed. The second seal, which is also segmented, may or may not define the substantially complete perimeter of the seal slot. If present, the second seal segments are circumferentially offset from the first seal segments to block the gaps between the first seal segments. A turbine vane including the present seal system is also disclosed.

42 ENGINEERING↗

Rotor for an electric machine

A rotor for an electric machine comprises a rotor core that defines a rotor slot having a central portion and an end portion. The end portion has a maximum width that is greater than a maximum width of the central portion immediately adjacent the end portion. A perimeter of the rotor slot at the end portion includes a plurality of segments extending between a first extremity at the maximum width of the end portion and a second extremity at the maximum width of the end portion. The plurality of segments include segments with different radii that decrease in magnitude from the center axis to the first extremity, and from the center axis to the second extremity.

Kim, Jihyun↗

Airfoil with CMC liner and multi-piece monolithic ceramic shell

An airfoil includes an airfoil section that has an airfoil wall that surrounds a cavity. The airfoil wall includes an exterior monolithic ceramic shell and an interior CMC liner that has CMC plies. An outermost ply of the CMC plies forms tabs that are raised from an underlying ply so as to define a slot. The exterior monolithic ceramic shell includes an underlapping shell piece and an overlapping shell piece. The underlapping shell piece has a portion disposed in the slot and bonded with the tabs. The overlapping shell piece extends over the tabs and is bonded to the tabs. There are channels bounded by adjacent ones of the tabs, the underlapping shell piece, and the overlapping shell piece. Channel orifices through the CMC liner connect the cavity and the channels.

Martin, Thomas J.↗

HVAC control fine-grained occupancy pattern estimation

A thermal state of a plurality of zones of the building is updated according to a building thermal model and information received from temperature sensors of the building. Predicted occupant counts for an upcoming plurality of time slots for each of the plurality of zones are updated using actual occupancy counts for each of the plurality of zones. A misprediction type distribution for the upcoming plurality of time slots for each of the plurality of zones is updated, the misprediction type distribution indicating misprediction for true negatives, false positives, false negatives, and true positives. A total misprediction cost expectation is updated according to the predicted occupant counts and the misprediction type distribution. HVAC power for each of the plurality of zones is determined to optimize occupant thermal comfort weighted according to the predicted occupant counts while minimizing the total misprediction cost expectation. HVAC operation is controlled per the HVAC power.

Lin, Shan↗

Self-governing bearing assembly

A self-governing bearing assembly is disclosed. The self-governing bearing assembly includes a stator and a rotor. The stator includes a brake contacting surface. The stator is one of an outer ring and an inner ring. The rotor includes the other of the outer ring and the inner ring, brake pads, and a circular spring. The brake pads are positioned radially from the brake contacting surface and adapted to rotate with the other of the outer ring and the inner ring. Each of the brake pads includes a pad retention slot. The circular spring is positioned within the pad retention slot of each of the brake pads. The bearing elements are axially aligned with a first bearing portion of the stator and a second bearing portion of the rotor. The bearing elements are adapted to rotationally support the rotor relative to the stator.

Bolton, Justin T.↗

Foreign material exclusion plug for structural threads with breakaway tab

A foreign material exclusion plug is disclosed. The foreign material plug includes a cylindrical body, a slot, and a breakaway tab. The cylindrical body includes an externally-threaded cylindrical structure. The slot is formed in the cylindrical body extending into the cylindrical body from a top surface of the cylindrical body. The breakaway tab is connected to the cylindrical body and extends outwards from the top surface.

Cole, Robert N.↗

Machines utilizing heavy rare earth free permanent magnets

Various examples are provided related to machines utilizing heavy rare earth (HRE) free permanent magnets. In one example, a rotor assembly including a rotor core having a plurality of rotor slots and magnets positioned within the plurality of rotor slots. At least a portion of the magnets are free of heavy rare earth (HRE) elements. The magnets can include a combination HRE segments and HRE-free segments or can be free of HRE elements. The rotor assembly can be included in an electric machine such as, e.g., a permanent magnet (PM) machine.

Islam, Md. Sariful↗

Manipulating Organic Semiconductor Morphology with Visible Light

A method is presented to manipulate the final morphology of roll-to-roll slot-die coated poly(3-hexylthiophene) (P3HT) by optically exciting the p-type polymer in solution while coating. These results provide a comprehensive picture of the entire knowledge chain, from demonstrating how to apply the authors’ method to a fundamental understanding of the changes in morphology and physical properties induced by exciting P3HT while coating. By combining results from density functional theory and molecular dynamics simulations with a variety of X-ray experiments, absorption spectroscopy, and THz spectroscopy, the relationship between morphology and physical properties of the thin film is demonstrated. Specifically, in P3HT films excited with light during deposition, changes in crystallinity and texture with more face-on orientation and increased out-of-plane charge mobility are observed.

36 MATERIALS SCIENCE↗

Impact of Salt Chemistry and Interlayer Architecture on Solid Electrolyte Interphase Composition and Performance

Reversible lithium metal anodes require interphases that are chemically stable, mechanically robust, and compatible with scalable processing. Here, we use slot-die-coated, salt-rich PEO interlayers to design SEI nanolayers on Cu current collectors and isolate how salt anion chemistry controls interphase composition and lithium plating/stripping behavior in architectures relevant to Li plating and anode-free cells. Mesoscale modeling shows that dendrite initiation at SEI defects is governed by a tradeoff among interphase thickness, ionic conductivity, and stiffness through defect-driven current focusing, motivating controlled formation from thin precursor layers. Using UHV-transferred XPS and ToF-SIMS depth profiling after controlled Li deposition, we find that fluorinated sulfonylimide salts (LiTFSI, LiFSI) form mixed inorganic/organic interphases containing LiF and PEO-derived alkoxides, with LiFSI producing a more LiF-dominant Li-facing surface than LiTFSI under identical conditions. In contrast, LiNO 3 -containing interlayers yield a comparatively thick nitrate-derived interphase that reduces upon Li contact to an N-rich inorganic layer (Li–N/N 3− , LiN x O y ). In Cu| |Li cells, these designed interlayers reduce interfacial resistance and improve Coulombic efficiency (CE) and critical current density (CCD) relative to uncoated controls, with LiFSI- and LiNO 3 -based interlayers providing the highest CE/CCD. Overall, the results demonstrate a manufacturing-relevant approach to engineer SEI nanolayers by salt chemistry, providing pathways to improve reversible lithium metal anodes while reducing reliance on LiTFSI.

anion chemistry↗

Roll-to-roll production of catalyst coated membranes for low-temperature electrolyzers

Here we demonstrate a roll-to-roll (R2R) process for direct coating of anode catalyst layers on a polymer electrolyte membrane for low-temperature water electrolysis. To develop this process, we studied catalyst ink formulation, ink-membrane interactions, and coating quality. The catalyst inks were a mixture of iridium oxide (IrO2) and Nafion in a water and alcohol dispersion medium. The type of alcohol (methanol, ethanol, propanols) and water-to-alcohol ratio were varied to determine their influence on membrane swelling, dispersion quality, and coatability. Interactions of the ink dispersion medium with the membrane were characterized using sessile-drop contact-angle measurements. These measurements show that the ratio of water to alcohol has a strong influence on how rapidly the dispersion media is absorbed by the membrane. Rheology of the catalyst inks was measured to understand the microstructure of the catalyst particles in the ink. This analysis found that 1-propanol leads to better dispersion of the IrO2 particles than ethanol. Small-scale coating samples were prepared to understand coating uniformity and formation of irregularities. Subsequently, two water/1-propanol ratios (90:10 and 75:25) were down-selected for large-scale R2R slot die coating. The R2R catalyst-coated membrane (CCM) coating process increased catalyst layer production throughput by over 500x compared to our standard lab-scale spray coating. The CCMs obtained from this process were tested as single-cell membrane electrode assemblies. They exhibited a cell voltage of 1.91 V at a current density of 2 A/cm2, which is comparable to spray-coated CCMs. In conclusion, the work presented here demonstrates a continuous, scalable manufacturing process that eliminates the need for the decal transfer step typically used in CCM production.

42 ENGINEERING↗