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Xu B.,University of Texas at AustinAustin
Color Research and Application | Year: 2015

To detect the layout of color yarns automatically, a novel projection-based fabric segmentation method is proposed to segment the double-system-mélange color fabric into several regions, which can be seen as single-system-mélange color fabrics. This method consists of five main steps: (1) yarn skew detection, (2) fabric image projecting, (3) projection curve smoothing, (4) variance curve calculating, and (5) curve peak confirmation. Based on the acquisition fabric image, the skew angles of warp and weft yarns are detected by Hough transform first. The projection curves of L, a, and b channels in Lab color model are generated and smoothed by Savitzky-Golay filter. The variance curves of L, a, and b are then calculated, and the peaks corresponding to the regional boundaries in each curve are detected. The regional boundaries are confirmed by synthesizing the curve peaks of L, a, and b. The experimental and theoretical analysis proves that the proposed method can segment the double-system-mélange color fabric into regions with satisfactory accuracy and good robustness. © 2015 Wiley Periodicals, Inc.

Jammes S.,Texas State University | Lavier L.L.,University of Texas at AustinAustin
Geochemistry, Geophysics, Geosystems | Year: 2016

We investigate how lithospheric scale compositional heterogeneities affect kilometric scale deformation processes. To this end, we perform numerical experiments of lithospheric extension in which we vary the Moho temperature and the mineralic composition of the mantle and the crust. In both the crust and the mantle, we use an explicit bimineralic composition by randomly distributing two mineral phases in the materials. Comparison of our models to simulations using an implicit bimineralic composite (one average viscous flow laws for a two-phase aggregate) crust and mantle demonstrates that an explicit bimineralic composition assimilated to heterogeneities succeeds in explaining observations related to the formation of rifted margins such a: (1) the absence of a sharp deformation zone at the brittle ductile transition (BDT), (2) the initiation of the rifting process as a wide delocalized rift system with multiple normal faults dipping in both directions; (3) the development of anastomosing shear zones in the middle/lower crust and the upper lithospheric mantle similar to the crustal scale anastomosing patterns observed in the field or in seismic data; (4) the preservation of undeformed lenses of material leading to lithospheric scale boudinage structure and resulting in the formation of continental ribbons as observed along the Iberian-Newfoundland margin. © 2016. American Geophysical Union. All Rights Reserved.

Wiese D.N.,Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadena | Killett B.,Pasadena California United States | Watkins M.M.,University of Texas at AustinAustin | Yuan D.-N.,Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadena
Journal of Geophysical Research: Oceans | Year: 2016

The extended length of the GRACE data time series (now 13.5 years) provides the unique opportunity to estimate global mass variations due to ocean tides at large (∼300 km) spatial scales. State-of-the-art global tide models rely heavily on satellite altimetry data, which are sparse for latitudes higher than 66°. Thus, the performance of the models is typically worse at higher latitudes. GRACE data, alternately, extend to polar latitudes and therefore provide information for both model validation and improvement at the higher latitudes. In this work, 11 years of GRACE inter-satellite range-acceleration measurements are inverted to solve for corrections to the amplitudes and phases of the major solar and lunar ocean tidal constituents (M2, K1, S2, and O1) from the GOT4.7 ocean tide model at latitudes south of 50°S. Two independent inversion and regularization methods are employed and compared against one another. Uncertainty estimates are derived by subtracting two independent solutions, each spanning a unique 5.5 years of data. Features above the noise floor in the derived solutions likely represent errors in GOT4.7. We find the GOT4.7 amplitudes to be generally too small for M2 and K1, and too large for S2 and O1, and to spatially correlate with geographic regions where GOT4.7 predicts the largest tidal amplitudes. In particular, we find GOT4.7 errors to be dominant over the Patagonia shelf (M2), the Filchner-Ronne Ice Shelf (M2 and S2), the Ross Ice Shelf (S2), and the Weddell and Ross Seas (K1 and O1). © 2016. American Geophysical Union. All Rights Reserved.

Chaudhary K.,Texas Tech University | Guiltinan E.J.,University of Texas at AustinAustin | Cardenas M.B.,University of Texas at AustinAustin | Maisano J.A.,University of Texas at AustinAustin | And 2 more authors.
Geochemistry, Geophysics, Geosystems | Year: 2015

We present a new method for measuring wettability or contact angle of minerals at reservoir pressure-temperature conditions using high-resolution X-ray computed tomography (HRXCT) and radiography. In this method, a capillary or a narrow slot is constructed from a mineral or a rock sample of interest wherein two fluids are allowed to form an interface that is imaged using X-rays. After some validation measurements at room pressure-temperature conditions, we illustrate this method by measuring the contact angle of CO2-brine on quartz, muscovite, shale, borosilicate glass, polytetrafluoroethylene (PTFE or Teflon), and polyether ether ketone (PEEK) surfaces at 60-71°C and 13.8-22.8 MPa. At reservoir conditions, PTFE and PEEK surfaces were found to be CO2-wet with contact angles of 140° and 127°, respectively. Quartz and muscovite were found to be water-wet with contact angles of 26° and 58°, respectively, under similar conditions. Borosilicate glass-air-brine at room conditions showed strong water-wet characteristics with a contact angle of 9°, whereas borosilicate glass-CO2-brine at 13.8 MPa and 60°C showed a decrease in its water-wetness with contact angle of 54°. This method provides a new application for X-ray imaging and an alternative to other methods. © 2015. American Geophysical Union. All Rights Reserved.

Bello-Rivas J.M.,The Texas Institute | Elber R.,University of Texas at AustinAustin
Journal of Computational Chemistry | Year: 2015

We investigated by computational means the kinetics and stationary behavior of stochastic dynamics on an ensemble of rough two-dimensional energy landscapes. There are no obvious separations of temporal scales in these systems, which constitute a simple model for the behavior of glasses and some biomaterials. Even though there are significant computational challenges present in these systems due to the large number of metastable states, the Milestoning method is able to compute their kinetic and thermodynamic properties exactly. We observe two clearly distinguished regimes in the overall kinetics: one in which diffusive behavior dominates and another that follows an Arrhenius law (despite the absence of a dominant barrier). We compare our results with those obtained with an exactly-solvable one-dimensional model, and with the results from the rough one-dimensional energy model introduced by Zwanzig. © 2015 Wiley Periodicals, Inc.

Chen X.,University of Texas at AustinAustin | Kianinejad A.,University of Texas at AustinAustin | Dicarlo D.A.,University of Texas at AustinAustin
Water Resources Research | Year: 2016

Relative permeability is the reduction of permeability of porous media when subjected to multiphase flow and a key parameter in subsurface hydrology. The JBN method is a well-known method of obtaining relative permeability, which measures the overall pressure drop and the effluent phase ratio versus time during two-phase displacements. By assuming no capillary pressure or gravity, the JBN method obtains the relative permeabilities to both phases at the core outlet. Since data across a range of saturations are acquired in a relatively short time, this method is widely used. This work extends the JBN method by having (1) section-wise pressure drop measurements between the core inlet, four pressure taps on the core and the outlet, (2) local saturation measurements, and (3) local phase fluxes. With these data, the extended JBN method can determine relative permeabilities to both phases at each pressure tap of the core (not just at the core outlet). The JBN extension is shown using a data set where CO2 invades a brine-filled core. From this it is found that the advantages of the extended JBN method over the regular JBN method are: (1) four times more data are obtained, and (2) data are more accurate because the capillary end effect is experimentally avoided. Avoiding the end effect results in tripling the saturation range, and obtaining relative permeabilities that are consistent with steady-state measurements and roughly 40% higher than those from the regular JBN method. © 2016. American Geophysical Union. All Rights Reserved.

Olinde L.,University of Texas at AustinAustin | Johnson J.P.L.,University of Texas at AustinAustin
Water Resources Research | Year: 2015

We present new measurements of bed load tracer transport in a mountain stream over several snowmelt seasons. Cumulative displacements were measured using passive tracers, which consisted of gravel and cobbles embedded with radio frequency identification tags. The timing of bed load motion during 11 transporting events was quantified with active tracers, i.e., accelerometer-embedded cobbles. Probabilities of cobble transport increased with discharge above a threshold, and exhibited slight to moderate hysteresis during snowmelt hydrographs. Dividing cumulative displacements by the number of movements recorded by each active tracer constrained average step lengths. Average step lengths increased with discharge, and distributions of average step lengths and cumulative displacements were thin tailed. Distributions of rest times followed heavy-tailed power law scaling. Rest time scaling varied somewhat with discharge and with the degree to which tracers were incorporated into the streambed. The combination of thin-tailed displacement distributions and heavy-tailed rest time distributions predict superdiffusive dispersion. © 2015. American Geophysical Union.

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