Publications

2017
J. Tudek, Crandall, D., Fuchs, S. J., Werth, C. J., Valocchi, A. J., Chen, Y., and Goodman, A., “In situ contact angle measurements of liquid CO2, brine, and Mount Simon sandstone core using micro X-ray CT imaging, sessile drop, and Lattice Boltzmann modeling,” Journal of Petroleum Science and Engineering, vol. 155, pp. 3-10, 2017. Publisher's VersionAbstract
Three techniques to measure and understand the contact angle, θ, of a CO2/brine/rock system relevant to geologic carbon storage were performed with Mount Simon sandstone. Traditional sessile drop measurements of CO2/brine on the sample were conducted and a water-wet system was observed, as is expected. A novel series of measurements inside of a Mount Simon core, using a micro X-ray computed tomography imaging system with the ability to scan samples at elevated pressures, was used to examine the θ of residual bubbles of CO2. Within the sandstone core the matrix appeared to be neutrally wetting, with an average θ around 90°. A large standard deviation of θ (20.8°) within the core was also observed. To resolve this discrepancy between experimental measurements, a series of Lattice Boltzmann model simulations were performed with differing intrinsic θ values. The model results with a θ=80° were shown to match the core measurements closely, in both magnitude and variation. The small volume and complex geometry of the pore spaces that CO2 was trapped in is the most likely explanation of this discrepancy between measured values, though further work is warranted.
A. Frooqnia, Torres-Verdín, C., and Sepehrnoori, K., “Inference of near-borehole permeability and water saturation from time-lapse oil-water production logs,” Journal of Petroleum Science and Engineering, vol. 152, no. April 2017, pp. 116-135, 2017.
C. Schroeder, Torres-Verdín, C., and Elshahawi, H., “Influence of mud-filtrate invasion effects on pressure gradients estimated from wireline formation-tester measurements (Expanded Abstract),” Society of Petrophysicists and Well Log Analysts (SPWLA) 58th Ann. Logging Symposium. Oklahoma City, OK, June 17-21, 2017.
S. Kelly, Torres-Verdín, C., and Balhoff, M., “Influence of polarity and hydration cycles on imbibition hysteresis in silica nanochannels,” Physical Chemistry Chemical Physics, vol. 20, pp. 456-466, 2017.
H. Jung, Singh, G., Nicolas Espinoza, D., Wheeler, M. F., and others,An Integrated Case Study of the Frio CO 2 Sequestration Pilot Test for Safe and Effective Carbon Storage Including Compositional Flow and Geomechanics,” in SPE Reservoir Simulation Conference, 2017.
V. Puzyrev, Torres-Verdín, C., and Calo, V., “Interpretation of deep directional resistivity measurements in high-angle and horizontal wells (Expanded Abstract),” Sixth International Symposium on Three-Dimensional Electromagnetics. Berkeley, CA, March 28-30, 2017.
E. D. Maalouf and Torres-Verdín, C., “Interpretation of sonic measurements acquired in high-angle and horizontal wells using 3D fast forward modeling (Expanded Abstract),” Society of Petrophysicists and Well Log Analysts (SPWLA) 58th Ann. Logging Symposium. Oklahoma City, OK, June 17-21, 2017.
W. Goth, Sacks, M. S., and Tunnell, J. W., “Interpreting fiber structure from polarization dependent optical anisotropy,” Proc. SPIE, vol. 10068. pp. 100680P-100680P-8, 2017. Publisher's VersionAbstract
Polarized light is commonly used to detect optical anisotropies, such as birefringence, in tissues. This optical anisotropy is often attributed to underlying structural anisotropy in tissue, which may originate from regularly aligned collagen fibers. In these cases, the optical anisotropy, such as birefringence, is interpreted as a relative measure of the structural anisotropy of the collagen fibers. However, the relative amplitude of optical anisotropy depends on factors other than fiber orientation, and few models allow quantitative interpretation of absolute measures of true fiber orientation distribution from the optical signal. Our model uses the Mie solution to scattering of linearly polarized light from infinite cylindrical scatterers. The model is expanded to include populations of scatterers with physiologically relevant size and orientation distributions. We investigated the influences of fiber diameter, orientation distribution, and wavelength on the back-scattering signal with our computational model, and used these results to extract structural information from experimental fiber phantoms and bovine tendon. Our results demonstrated that by fitting our model to the experimental data using limited assumptions, we could extract fiber orientation distributions and diameters that were comparable to those found in scanning electron microscope images of the same fiber sample. We found a higher alignment of fibers in the bovine tendon sample, and the extracted fiber diameter was within the expected physiological range. Our model showed that the amplitude of optical anisotropy can vary widely due to factors other than the orientation distribution of fiber structures, including index of refraction, and therefore should not be taken as a sole indicator of structural anisotropy. This work highlights that the accuracy of model assumptions plays a crucial role in extracting quantitative structural information from optical anisotropy.
E. Maalouf and Torres-Verdín, C., “Inversion-based method to mitigate noise in borehole sonic logs,” Geophysics, vol. 83, no. 2, pp. D61-D71, 2017.
C. Wang, Ren, P., and Luo, R., “Ionic Solution: What Goes Right and Wrong with Continuum Solvation Modeling,” The Journal of Physical Chemistry B, vol. 121, pp. 11169–11179, 2017.
J. Zhang, Jia, S., Kholmanov, I., Dong, L., Er, D., Chen, W., Guo, H., Jin, Z., Shenoy, V. B., Shi, L., and Lou, J., “Janus Monolayer Transition Metal Dichalcogenides,” ACS Nano, vol. 11, pp. 8192 , 2017. Publisher's Version
E. Ortega, Luycx, M., Torres-Verdín, C., and Preeg, W. E., “Joint petrophysical interpretation of multi-detector nuclear measurements in the presence of invasion, shoulder-bed, and well-deviation effects,” Geophysics, vol. 82, no. 1, pp. D13-D30, 2017.
E. Ortega, Luycx, M., Torres-Verdín, C., and Preeg, W. E., “Joint petrophysical interpretation of multi-detector nuclear measurements in the presence of invasion, shoulder-bed, and well-deviation effects.,” Geophysics, vol. 82, no. 1, pp. D13-D30, 2017.
J. Liu, Su, X., Han, M., Wu, D., Gray, D. L., Shapley, J. R., Werth, C. J., and Strathmann, T. J., “Ligand Design for Isomer-Selective Oxorhenium(V) Complex Synthesis,” Inorganic Chemistry, vol. 56, no. 3, pp. 1757-1769, 2017. Publisher's VersionAbstract
Recently, N,N-trans Re(O)(LN–O)2X (LN–O = monoanionic N–O chelates; X = Cl or Br prior to being replaced by solvents or alkoxides) complexes have been found to be superior to the corresponding N,N-cis isomers in the catalytic reduction of perchlorate via oxygen atom transfer. However, reported methods for Re(O)(LN–O)2X synthesis often yield only the N,N-cis complex or a mixture of trans and cis isomers. This study reports a geometry-inspired ligand design rationale that selectively yields N,N-trans Re(O)(LN–O)2Cl complexes. Analysis of the crystal structures revealed that the dihedral angles (DAs) between the two LN–O ligands of N,N-cis Re(O)(LN–O)2Cl complexes are less than 90°, whereas the DAs in most N,N-trans complexes are greater than 90°. Variably sized alkyl groups (−Me, −CH2Ph, and −CH2Cy) were then introduced to the 2-(2′-hydroxyphenyl)-2-oxazoline (Hhoz) ligand to increase steric hindrance in the N,N-cis structure, and it was found that substituents as small as −Me completely eliminate the formation of N,N-cisisomers. The generality of the relationship between N,N-trans/cis isomerism and DAs is further established from a literature survey of 56 crystal structures of Re(O)(LN–O)2X, Re(O)(LO–N–N–O)X, and Tc(O)(LN–O)2X congeners. Density functional theory calculations support the general strategy of introducing ligand steric hindrance to favor synthesis of N,N-trans Re(O)(LN–O)2X and Tc(O)(LN–O)2X complexes. This study demonstrates the promise of applying rational ligand design for isomeric control of metal complex structures, providing a path forward for innovations in a number of catalytic, environmental, and biomedical applications.
M. Nole, Daigle, H., Cook, A. E., Hillman, J. I. T., and Malinverno, A., “Linking basin‐scale and pore‐scale gas hydrate distribution patterns in diffusion‐dominated marine hydrate systems,” Geochemistry, Geophysics, Geosystems, 2017.
J. M. Obliosca, Cheng, S. Y., Chen, Y. - A., Llanos, M. F., Liu, Y. - L., Imphean, D. M., Bell, D., Petty, J. T., Ren, P., and Yeh, H. - C., “LNA Thymidine Monomer Enables Differentiation of the Four Single-Nucleotide Variants by Melting Temperature,” Journal of the American Chemical Society, 2017.
K. Chen, Sheehan, N., He, F., Meng, X., Mason, S. C., Bank, S. R., and Wang, Y., “Measurement of Ambipolar Diffusion Coefficient of Photoexcited Carriers with Ultrafast Reflective Grating-Imaging Technique,” ACS Photonics, 2017. Publisher's VersionAbstract
A novel ultrafast reflective grating-imaging technique has been developed to measure ambipolar carrier diffusion in GaAs/AlAs quantum wells and bulk GaAs. By integrating a transmission grating and an imaging system into the traditional pump–probe setup, this technique can acquire carrier diffusion properties conveniently and accurately. The fitted results of the diffusion coefficient and diffusion length in bulk GaAs agree well with the literature values obtained by other techniques. The diffusion coefficient and diffusion length of GaAs/AlAs quantum wells are found to increase with the well layer thickness, which suggests that interface roughness scattering dominates carrier diffusion in GaAs/AlAs quantum wells. With the advantages of simple operation, sensitive detection, rapid and nondestructive measurement, and extensive applicability, the ultrafast reflective grating-imaging technique has great potential in experimental study of carrier diffusion in various materials.
PDF icon PDF
R. Victor, Prodanović, M., and Torres-Verdín, C., “Monte Carlo approach for estimating density and atomic number from dual-energy computed tomography images of carbonate rocks,” Journal of Geophysical Research – Solid Earth, vol. 122, pp. 9804-9824, 2017.
Z. Zhao, Luan, L., Wei, X., Zhu, H., Li, X., Lin, S., Siegel, J. J., Chitwood, R. A., and Xie, C., “Nanoelectronic coating enabled versatile multi-functional neural probes,” Nano Letters, 2017. Publisher's VersionAbstract
Brain function can be best studied by simultaneous measurements and modulation of the multifaceted signaling at the cellular scale. Extensive efforts have been made to develop multifunctional neural probes, typically involving highly specialized fabrication processes. Here, we report a novel multifunctional neural probe platform realized by applying ultra-thin nanoelectronic coating (NEC) on the surfaces of conventional microscale devices such as optical fibers and micropipettes. We fabricated the NECs by planar photolithography techniques using a substrate-less and multi-layer design, which host arrays of individually addressed electrodes with an overall thickness below 1 µm. Guided by an analytic model and taking advantage of the surface tension, we precisely aligned and coated the NEC devices on the surfaces of these conventional micro-probes, and enabled electrical recording capabilities on par with the state-of-the-art neural electrodes. We further demonstrated optogenetic stimulation and controlled drug infusion with simultaneous, spatially resolved neural recording in a rodent model. This study provides a low-cost, versatile approach to construct multifunctional neural probes that can be applied to both fundamental and translational neuroscience.
S. V. Sreenivasan, “Nanoimprint lithography steppers for volume fabrication of leading-edge semiconductor integrated circuits,” Microsystems & Nanoengineering, vol. 2017, no. 3, 2017. Publisher's VersionAbstract
This article discusses the transition of a form of nanoimprint lithography technology, known as Jet and Flash Imprint Lithography (J-FIL), from research to a commercial fabrication infrastructure for leading-edge semiconductor integrated circuits (ICs). Leading-edge semiconductor lithography has some of the most aggressive technology requirements, and has been a key driver in the 50-year history of semiconductor scaling. Introducing a new, disruptive capability into this arena is therefore a case study in a "highrisk-high-reward" opportunity. This article first discusses relevant literature in nanopatterning including advanced lithography options that have been explored by the IC fabrication industry, novel research ideas being explored, and literature in nanoimprint lithography. The article then focuses on the J-FIL process, and the interdisciplinary nature of risk, involving nanoscale precision systems, mechanics, materials, material delivery systems, contamination control, and process engineering. Next, the article discusses the strategic decisions that were made in the early phases of the project including: (i) choosing a step and repeat process approach; (ii) identifying the first target IC market for J-FIL; (iii) defining the product scope and the appropriate collaborations to share the risk-reward landscape; and (iv) properly leveraging existing infrastructure, including minimizing disruption to the widely accepted practices in photolithography. Finally, the paper discusses the commercial J-FIL stepper system and associated infrastructure, and the resulting advances in the key lithographic process metrics such as critical dimension control, overlay, throughput, process defects, and electrical yield over the past 5 years. This article concludes with the current state of the art in J-FIL technology for IC fabrication, including description of the high volume manufacturing stepper tools created for advanced memory manufacturing.

Pages