Electrothermal Instability Evolution on Z-Pinch Rods and Imploding Liners Pulsed with Intense Current
Abstract not provided.
Publications
On the evolution from micrometer-scale inhomogeneity to global overheated structure during the intense joule heating of a z-pinch rod
IEEE Transactions on Plasma Science
Ultrafast optical microscopy of metal z-pinch rods pulsed with megaampere current is contributing new data and critical insight into what provides the fundamental seed for the magneto-Rayleigh-Taylor (MRT) instability. A two-frame near infrared/visible intensified-charge-coupled device gated imager with 2-ns temporal resolution and 3-μm spatial resolution captured emissions from the nonuniformly Joule heated surfaces of ultrasmooth aluminum (Al) rods. Nonuniform surface emissions are consistently first observed from discrete, 10-μm scale, subelectronvolt spots. Aluminum 6061 alloy, with micrometer-scale nonmetallic resistive inclusions, forms several times more spots than 99.999% pure Al 5N; 5-10 ns later, azimuthally stretched elliptical spots and distinct strata (40-100μm wide by 10μm tall) are observed on Al 6061, but not on Al 5N. Such overheat strata, which are aligned parallel to the magnetic field, are highly effective seeds for MRT instability growth. These data give credence to the hypothesis that early nonuniform Joule heating, such as the electrothermal instability, may provide the dominant seed for MRT.
Predicting the Reliability of Package-on-Package-Package (PoPoP) Interconnections Based on Accelerated Aging Experiments and Computational Modeling
Abstract not provided.
predicting the reliability of package-on-package-on-package (popop) interconnections based on accelerated aging experiments and computational modeling
Abstract not provided.
Positive Thermal Conductivity Change in PZT Thin Foilms Under Applied Fields via Substrate Clamping Relief
Abstract not provided.
Domain imaging in ferroelectric thin films via channeling-contrast backscattered electron microscopy
Journal of Materials Science
Ferroelastic domain walls provide opportunities for deterministically controlling mechanical, optical, electrical, and thermal energy. Domain wall characterization in micro- and nanoscale systems, where their spacing may be of the order of 100 nm or less is presently limited to only a few techniques, such as piezoresponse force microscopy and transmission electron microscopy. These respective techniques cannot, however, independently characterize domain polarization orientation and domain wall motion in technologically relevant capacitor structures or in a non-destructive manner, thus presenting a limitation of their utility. In this work, we show how backscatter scanning electron microscopy utilizing channeling contrast yield can image the ferroelastic domain structure of ferroelectric films with domain wall spacing as narrow as 10 nm. Combined with electron backscatter diffraction to identify grain orientations, this technique provides information on domain orientation and domain wall type that cannot be readily measured using conventional non-destructive methods. In addition to grain orientation identification, this technique enables dynamic domain structure changes to be observed in functioning capacitors utilizing electrodes that are transparent to the high-energy backscattered electrons. This non-destructive, high-resolution domain imaging technique is applicable to a wide variety of ferroelectric thin films and a multitude of material systems where nanometer-scale crystallographic twin characterization is required.
Emergence & Progression of Abnormal Grain Growth in Minimally Strained Nickel-200
Abstract not provided.
Backscattered Scanning Electron Microscopy Domain Imaging of Ferroelectric Films: in operando Ferroelectric Domain Structure Characterization
Abstract not provided.
Development of the electrothermal instability from resistive inclusions
Abstract not provided.
Understanding Cu-Al limited-volume diffusion and lifetime prediction for Cu wire bonds
Abstract not provided.
Understanding Cu-Al Limited-Volume Diffusion Towards Lifetime Prediction for Cu Wire Bonds
Abstract not provided.
ETI Growth under Dielectric Coatings
Abstract not provided.
Transformation of amorphous TiO2 to a hydronium oxofluorotitanate and applications as an HF sensor
Sensors and Actuators, B: Chemical
Amorphous titania thin films were examined for use as the active material in a polarimetry based HF sensor. The amorphous titania films were found to be sensitive to vapor phase HF and the reaction product was identified as a hydronium oxofluorotitanate phase, which has previously only been synthesized in aqueous solution. The extent of reaction varied both with vapor phase HF concentration, relative humidity, and the exposure time. HF concentrations as low as 1 ppm could be detected for exposure times of 120 h.
Characterization of Void-Dominated Ductile Failure in Pure Ta
Abstract not provided.
Onset of Abnormal Grain Growth in Nickel-200 Within the Low-Strain Regime
Abstract not provided.
Backscattered Scanning Electron Microscopy Domain Imaging of Ferroelectric Films
Abstract not provided.
Sodium-Ion Conductivity and Scaling Effects in NaSICon Thin Films Prepared Via Chemical Solution Deposition
Abstract not provided.
Characterization of fire hazards of aged photovoltaic balance-of-systems connectors
2015 IEEE 42nd Photovoltaic Specialist Conference, PVSC 2015
Three balance of systems (BOS) connector designs common to industry were investigated as a means of assessing reliability from the perspective of arc fault risk. These connectors were aged in field and laboratory environments and performance data captured for future development of a reliability model. Comparison of connector resistance measured during damp heat, mixed flowing gas and field exposure in a light industrial environment indicated disparities in performance across the three designs. Performance was, in part, linked to materials of construction. A procedure was developed to evaluate new and aged connectors for arc fault risk and tested for one of the designs. Those connectors exposed to mixed flowing gas corrosion exhibited considerable Joule heating that may enhance arcing behavior, suggesting temperature monitoring as a potential method for arc fault prognostics. These findings, together with further characterization of connector aging, can provide operators of photovoltaic installations the information necessary to develop a data-driven approach to BOS connector maintenance as well as opportunities for arc fault prognostics.
Voltage Tunable Thermal Conductivity in Ferroelectric Thin Films via Reconfigurable Domain Walls
Abstract not provided.
Establishing a Ti-Cu-Pt-Au Thin Film Conductor on Low-Temperature Co-Fired Ceramic (LTCC) for High Temperature Electronics
Abstract not provided.
Direct observation of electrothermal instability structures in the skin layer of an intensely Ohmically heated conductor
Magnetically driven implosions (MDIs) on the Z Facility assemble high-energy-density plasmas for radiation effects and ICF experiments. MDIs are hampered by the Magneto-Rayleigh-Taylor (MRT) instability, which can grow to large amplitude from a small seed perturbation, limiting achievable stagnation pressures and temperatures. The metallic liners used in Magnetized Liner Inertial Fusion (MagLIF) experiments include astonishingly small (-10 nm RMS) initial surface roughness perturbations; nevertheless, unexpectedly large MRT amplitudes are observed in experiments. An electrothermal instability (ETI) may provide a perturbation which exceeds the initial surface roughness. For a condensed metal resistivity increases with temperature. Locations of higher resistivity undergo increased Ohmic heating, resulting in locally higher temperature, and thus still higher resistivity. Such unstable temperature (and pressure) growth produces density perturbations when the locally overheated metal changes phase, providing the seed perturbation for MRT growth. ETI seeding of MRT on thick conductors carrying current in a skin layer has thus far only been inferred by evaluating MRT amplitude late in the experiment. A direct observation of ETI is vital to ensure our simulation tools are accurately representing the seed of the deleterious MRT instability. In this LDRD project, ETI growth was directly observed on the surface of 1.0-mm-diameter solid Al rods which were pulsed with 1 MA of current in 100 ns. Fine structures resulting from ETI-driven temperature variations were observed directly through high resolution gated optical imaging. Data from two Aluminum alloys (6061 and 5N) and a variety fabrication techniques (conventional machining, single-point diamond turned, electropolished) enable evaluation of which imperfections provide a seed for ETI growth and subsequent plasma initiation. Data is relevant to the early stages of MagLIF liner implosions, when the ETI seed of MRT may be initiated, and provides a fundamentally new dataset with which to test our state-of-the-art simulation tools.
Comparison of horizontally and vertically positioned cameras for TKD
Abstract not provided.
A multi-stimuli responive, self-assembling, boronic acid dipeptide
ChemComm
Modification of the dipeptide of phenylalanine, FF, with a boronic acid (BA) functionality imparts unique aqueous self-assembly behavior that responds to multiple stimuli. Changes in pH and ionic strength are used to trigger hydrogelation via the formation of nanoribbon networks. Thus, we show for the first time that the binding of polyols to the BA functionality can modulate a peptide between its assembled and disassembled states.
ESTABLISHING A TI-CU-PT-AU THIN FILM ? ON ? LOW TEMPERATURE CO-FIRED CERAMIC (LTCC) TECHNOLOGY FOR HIGH TEMPERATURE ELECTRONICS
Abstract not provided.
Electric Field Tuning of Thermal Conductivity in Ferroelectric Thin Films by Reconfiguring Ferroelastic Domain Walls
Abstract not provided.
Results 26–50 of 151