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PE1 Site Characterization: Data Documentation on Geologic and Hydrologic Lab Testing

Wilson, Jennifer E.; Heath, Jason; Kuhlman, Kristopher L.; Xu, Guangping X.; Bodmer, Miles A.; Broome, Scott T.; Jaramillo, Johnny L.; Barrow, Perry C.; Rodriguez, Mark A.; Griego, James J.M.; Valdez, Nichole R.

This data documentation report describes geologic and hydrologic laboratory analysis and data collected in support of site characterization of the Physical Experiment 1 (PE1) testbed, Aqueduct Mesa, Nevada. The documentation includes a summary of laboratory tests performed, discussion of sample selection for assessing heterogeneity of various testbed properties, methods, and results per data type.

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Liquid crystalline behavior and photoluminescence of lanthanide decanoate nanoparticles synthesized by microwave radiation

Dalton Transactions

Davis-Wheeler, Clare D.; Lee, Harold O.; Griego, James J.M.; Treadwell, LaRico J.

Luminescent lanthanide decanoate nanoparticles (LnC10NPs; Ln = Pr, Nd, Sm, Eu, Gd, Er) with spherical morphology (<100 nm) have been synthesizedviaa facile microwave (MWV) method using Ln(NO3)3·xH2O, ethanol/water, and decanoic acid. These hybrid nanomaterials adopt a lamellar structure consisting of inorganic Ln3+layers separated by a decanoate anion bilayer and exhibit liquid crystalline (LC) phases during melting. The particle size, crystalline structure, and LC behavior were characterized using transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and powder X-ray diffraction (ambient and heated). Thermal analysis indicated the formation of Smectic A LC phases by LnC10nanoparticles, with the smaller lanthanides (Ln = Sm, Gd, Er) displaying additional solid intermediate and Smectic C phases. The formation of LC phases by the smaller Ln3+suggests that these nanoscale materials have vastly different thermal properties than their bulk counterparts, which do not exhibit LC behavior. Photoluminescence spectroscopy revealed the LnC10NPs to be highly optically active, producing strong visible emissions that corresponded to expected electronic transitions by the various Ln3+ions. Under long-wave UV irradiation (λ= 365 nm), bright visible luminescence was observed for colloidal suspensions of Nd, Sm, Eu, Gd, and ErC10NPs. To the best of the authors’ knowledge, this is the first reported synthesis of nanoscale metal alkanoates, the first report of liquid crystalline behavior by any decanoate of lanthanides smaller than Nd, and the first observation of strong visible luminescence by non-vitrified lanthanide alkanoates.

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Use of a Be-dome holder for texture and strain characterization of Li metal thin films via sin(ψ) methodology

Powder Diffraction

Rodriguez, Mark A.; Harrison, Katharine L.; Goriparti, Subrahmanyam G.; Griego, James J.M.; Boyce, Brad B.; Perdue, Brian R.

Residual strain in electrodeposited Li films may affect safety and performance in Li metal battery anodes, so it is important to understand how to detect residual strain in electrodeposited Li and the conditions under which it arises. To explore this Li films, electrodeposited onto Cu metal substrates, were prepared under an applied pressure of either 10 or 1000 kPa and subsequently tested for the presence or absence of residual strain via sin(ψ) analysis. X-ray diffraction (XRD) analysis of Li films required preparation and examination within an inert environment; hence, a Be-dome sample holder was employed during XRD characterization. Results show that the Li film grown under 1000 kPa displayed a detectable presence of in-plane compressive strain (-0.066%), whereas the Li film grown under 10 kPa displayed no detectable in-plane strain. The underlying Cu substrate revealed an in-plane residual strain near zero. Texture analysis via pole figure determination was also performed for both Li and Cu and revealed a mild fiber texture for Li metal and a strong bi-axial texture of the Cu substrate. Experimental details concerning sample preparation, alignment, and analysis of the particularly air-sensitive Li films have also been detailed. This work shows that Li metal exhibits residual strain when electrodeposited under compressive stress and that XRD can be used to quantify that strain.

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Executive Micro-CT Low-resolution Summary for Catheter Parts [Slides]

Griego, James J.M.; Noell, Philip N.

Data scans were performed on a Zeiss Xradia 520 Versa operated by departments 1851 (Philip Noell) and 1819 (James Griego). Sample 1, 2, and 3 Catheters were scanned with a 30 um pixel (low-resolution) to get an overall view of the part. (This does not include the entire height of the catheter assembly.) The following slides show the Z, Y, and X slice plane at a specific cross-hair location. We can perform a higher resolution scan down to —0.7 um pixel size including a limited field of view of ~700 um wide. Slide 5 has some requests for the customer for further scan locations. These catheters were provided to us by Simon Dunham of Weill Cornell Medical College.

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Effect of thermal annealing on microstructure evolution and mechanical behavior of an additive manufactured AlSi10Mg part

Journal of Materials Research

Yang, Pin Y.; Rodriguez, Mark A.; Deibler, Lisa A.; Jared, Bradley H.; Griego, James J.M.; Kilgo, Alice C.; Allen, Amy A.; Stefan, Daniel K.

The powder-bed laser additive manufacturing (AM) process is widely used in the fabrication of three-dimensional metallic parts with intricate structures, where kinetically controlled diffusion and microstructure ripening can be hindered by fast melting and rapid solidification. Therefore, the microstructure and physical properties of parts made by this process will be significantly different from their counterparts produced by conventional methods. This work investigates the microstructure evolution for an AM fabricated AlSi10Mg part from its nonequilibrium state toward equilibrium state. Special attention is placed on silicon dissolution, precipitate formation, collapsing of a divorced eutectic cellular structure, and microstructure ripening in the thermal annealing process. These events alter the size, morphology, length scale, and distribution of the beta silicon phase in the primary aluminum, and changes associated with elastic properties and microhardness are reported. The relationship between residual stress and silicon dissolution due to changes in lattice spacing is also investigated and discussed.

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Results 1–25 of 52
Results 1–25 of 52