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Local Electrochemical Investigation of Single Grains of Polycrystalline Cu-16%Zn-8%Al Alloy

Barragan, Jose T. C.; Blanco, Matildes; Barelli, Nilso; Della Noce, Rodrigo; Fugivara, Cecilio S.; Fernandez, Javier; Benedetti, Assis V.
Fonte: Soc Brasileira Quimica Publicador: Soc Brasileira Quimica
Tipo: Artigo de Revista Científica Formato: 2108-2114
ENG
Relevância na Pesquisa
36.51%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Processo FAPESP: 04/11984-2; Local electrochemical studies of single grains of a polycrystalline Cu-16%Zn-8%Al alloy were investigated in borate buffer solution (pH 8.4) by means of microelectrochemical technique. The grain orientations, which were determined by the Laue back-reflection method, were predominantly close to [110] direction, suggesting that the sample was texturized. The open circuit potential measurements showed that the lower steady state potential was observed for the grain which has the highest number of steps on the alloy surface. The cyclic voltammetry experiments suggested that the orientation of Cup follows the substrate one in the Cu-Zn-Al alloy, while CuO grows independently.

The influence of crystallization route on the SrBi2Nb2O9 thin films

Zanetti, S. M.; Leite, E. R.; Longo, Elson; Varela, José Arana
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 1026-1031
ENG
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26.53%
Polycrystalline SrBi2Nb2O9-layered ferroelectric thin films were synthesized on Pt/Ti/SiO2/Si substrate using the polymeric precursors solution. The dip-coated films were specular and crack-free and crystallized during firing at 700 °C. Single-, double-, and triple-layered films were obtained by several dips in the deposition solution, and the influence of crystallization between each dip was studied. Microstructure and morphological evaluation were followed by grazing incident x-ray diffraction (GIXRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Multilayered films obtained using the intermediate-crystallized layer route present a dense microstructure with spherical grains, with a preferential orientation in the 〈215〉 direction; films obtained using the intermediate-amorphous layer route are polycrystalline and present elongated grains around 250 nm in size.

Structural transition of ZnO thin films produced by RF magnetron sputtering at low temperatures

Rosa, A. M.; Da Silva, E. P.; Chaves, M.; Trino, L. D.; Lisboa Filho, Paulo Noronha; Da Silva, T. F.; Durrant, S. F.; Bortoleto, J. R R
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 3143-3148
ENG
Relevância na Pesquisa
46.57%
Zinc oxide (ZnO) thin films were prepared using reactive radio-frequency magnetron sputtering of a pure metallic zinc target onto glass substrates. The evolution of the surface morphology and the optical properties of the films were studied as a function of the substrate temperature, which was varied from 50 to 250 C. The surface topography of the samples was examined using atomic force microscopy (AFM), and their optical properties were studied via transmittance measurements in the UV-Vis-NIR region. DRX and AFM analyses showed that the surface morphology undergoes a structural transition at substrate temperatures of around 150 C. Actually, at 50 C the formation of small grains was observed while at 250 C the grains observed were larger and had more irregular shapes. The optical gap remained constant at ∼3.3 eV for all films. In the visible region, the average optical transmittance was 80 %. From these results, one can conclude that the morphological properties of the ZnO thin films were more greatly affected by the substrate temperature, due to mis-orientation of polycrystalline grains, than were the optical properties. © 2013 Springer Science+Business Media New York.

Local electrochemical investigation of single grains of polycrystalline Cu-16%Zn-8%Al alloy

Barragan,José T. C.; Blanco,Matildes; Barelli,Nilso; Noce,Rodrigo Della; Fugivara,Cecílio S.; Fernández,Javier; Benedetti,Assis V.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2011 EN
Relevância na Pesquisa
36.51%
Local electrochemical studies of single grains of a polycrystalline Cu-16%Zn-8%Al alloy were investigated in borate buffer solution (pH 8.4) by means of microelectrochemical technique. The grain orientations, which were determined by the Laue back-reflection method, were predominantly close to [110] direction, suggesting that the sample was texturized. The open circuit potential measurements showed that the lower steady state potential was observed for the grain which has the highest number of steps on the alloy surface. The cyclic voltammetry experiments suggested that the orientation of Cu2O follows the substrate one in the Cu-Zn-Al alloy, while CuO grows independently.

Grain-Scale Modeling Approaches for Polycrystalline Aggregates

SIMONOVSKI IGOR; CIZELJ Leon
Fonte: InTech Publicador: InTech
Tipo: Articles in books Formato: Printed
ENG
Relevância na Pesquisa
26.5%
In polycrystalline aggregates microstructure plays an important role in the evolution of stresses and strains and consequently development of damage processes such as for example evolution of microstructurally small cracks and fatigue. Random grain shapes and sizes, combined with different crystallographic orientations, inclusions, voids and other microstructural features result in locally anisotropic behavior of the microstructure with direct influence on the damage initialization and evolution (Hussain, 1997; Hussain et al., 1993; King et al., 2008a; Miller, 1987). To account for these effects grain-scale or meso-scale models of polycrystalline aggregates are being developed and are increasingly being used. In this chapter we present some of the most often used approaches to modeling polycrystalline aggregates, starting from more simplistic approaches and up to the most state-of-the art approaches that draw on the as-measured properties of the microstructure. The models are usually based on the finite element approach and differ by a) the level to which they account for the complex geometry of polycrystalline aggregates and b) the sophistication of the used constitutive model. In some approaches two dimensional models are used with grains approximated using simple geometrical shapes like rectangles (Bennett & McDowell...

Étude numérique du comportement en fatigue à grand nombre de cycles d’agrégats polycristallins de cuivre; Numerical study of high cycle fatigue behaviour of copper polycrystalline aggregates

ROBERT, Camille; SAINTIER, Nicolas; PALIN-LUC, Thierry; MOREL, Franck
Fonte: EDP Publicador: EDP
EN_US
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26.53%
Numerical study of high cycle fatigue behaviour of copper polycrystalline aggre- gates. An analysis of high cycle fatigue behaviour is undertaken via the numerical simulation of polycrystalline aggregates. The metallic material chosen for investigation is Copper, which has a FCC crystalline structure. The REV, which is composed of 300 randomly orientated equiaxed grains, is loaded at the fatigue limit determined at 10/7 cycles. The aim is to calculate the mechanical quantities at the mesoscopic scale (average quantities in the grains) after cyclic stabilisation has been achieved. The results highlight the fact that the mechanical quantities at this scale have a large scatter. A statistical analysis of the response of the aggregate for different loading conditions (tensile, torsion, and in-phase tension-torsion) is done. Thanks to the sufficiently large number of different microstructures investigated, a critical analysis of the Dang Van and Crossland multiaxial fatigue criteria has been undertaken, using the local mechanical quantities.

Structural characterisation of polycrystalline colloidal monolayers in the presence of aspherical impurities

Gray, Andrew T.; Mould, Elizabeth; Royall, C. Patrick; Williams, Ian
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.42%
Impurities in crystalline materials introduce disorder into an otherwise ordered structure due to the formation of lattice defects and grain boundaries. The properties of the resulting polycrystal can differ remarkably from those of the ideal single crystal. Here we investigate a quasi-two-dimensional system of colloidal spheres containing a small fraction of aspherical impurities and characterise the resulting polycrystalline monolayer. We find that, in the vicinity of an impurity, the underlying hexagonal lattice is deformed due to a preference for 5-fold co-ordinated particles adjacent to impurities. This results in a reduction in local hexagonal ordering around an impurity. Increasing the concentration of impurities leads to an increase in the number of these defects and consequently a reduction in system-wide hexagonal ordering and a corresponding increase in entropy as measured from the distribution of Voronoi cell areas. Furthermore, through both considering orientational correlations and directly identifying crystalline domains we observe a decrease in the average polycrystalline grain size on increasing the concentration of impurities. Our data show that, for the concentrations considered, local structural modifications due to the presence of impurities are independent of their concentration...

Effect of the indium addition on the superconducting property and the impurity phase in polycrystalline SmFeAsO1-xFx

Fujioka, Masaya; Ozaki, Toshinori; Takeya, Hiroyuki; Deguchi, Keita; Demura, Satoshi; Hara, Hiroshi; Watanabe, Tohru; James, Denholme Saleem; Okazaki, Hiroyuki; Yamaguchi, Takahide; Kumakura, Hiroaki; Takano, Yoshihiko
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 21/10/2012
Relevância na Pesquisa
26.75%
We report enhancement in the magnetic critical current density of indium added polycrystalline SmFeAsO1-xFx. The value of magnetic Jc is around 25 kA/cm2 at 4.2 K under self-magnetic field. Polycrystalline SmFeAsO1-xFx is mainly composed of the superconducting grains and a little of amorphous FeAs compounds. These areas randomly co-exist and amorphous areas are located between superconducting grains. Therefore, the superconducting current is prevented by the amorphous areas. In this study, it is found that indium addition to polycrystalline SmFeAsO1-xFx removes these amorphous areas and induces the bringing together the superconducting grains. It means the total contact surfaces of grains are increased. We suggest that the enhancement of the magnetic critical current density is a direct effect of the indium addition.; Comment: 18 pages, 5 figures

Two-dimensional nanovaristors at grain boundaries account for memristive switching in polycrystalline BiFeO3

Shen, Xiao; Yin, Kuibo; Puzyrev, Yevgeniy S.; Liu, Yiwei; Sun, Litao; Li, Run-Wei; Pantelides, Sokrates T.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 12/03/2015
Relevância na Pesquisa
26.6%
Memristive switching in polycrystalline materials is widely attributed to the formation and rupture of conducting filaments, believed to be mediated by oxygen-vacancy redistribution. The underlying atomic-scale processes are still unknown, however, which limits device modeling and design. Here we combine experimental data with multi-scale calculations to elucidate the entire atomic-scale cycle in undoped polycrystalline BiFeO3. Conductive atomic force microscopy reveals that the grain boundaries behave like two-dimensional nanovaristors while, on the return part of the cycle, the decreasing current is through the grains. Using density-functional-theory and Monte-Carlo calculations we deduce the atomic-scale mechanism of the observed phenomena. Oxygen vacancies in non-equilibrium concentrations are initially distributed relatively uniformly, but they are swept into the grain boundaries by an increasing voltage. A critical voltage, the SET voltage, then eliminates the barrier for hopping conduction through vacancy energy levels in grain boundaries. On the return part of the cycle, the grain boundaries are again non-conductive, but the grains show nonzero conductivity by virtue of remote doping by oxygen vacancies. The RESET voltage amounts to a heat pulse that redistributes the vacancies. The realization that nanovaristors are at the heart of memristive switching in polycrystalline materials may open possibilities for novel devices and circuits.

Impedance spectroscopy study on post-annealing-tuned polycrystalline CaCu3Ti4O12 films: Evidence of Barrier Layer Capacitor Effects

Fang, Liang; Shen, Mingrong; Li, Zhenya; Cao, Wenwu
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
26.75%
In this paper, impedance spectroscopy study was performed to establish the electrical property and microstructure relations of the as-deposited and post-annealed polycrystalline CCTO films prepared on Pt/Ti/SiO2/Si (100) substrates by pulsed-laser deposition (PLD). Our results demonstrated that the as-deposited polycrystalline CCTO film was made of insulating grain boundaries with semiconducting grains, indicating that the high-dielectric-constant is attributed to the barrier layer capacitor (BLC) effects. The simple resistor-capacitor (RC) equivalent circuit and the modified constant phase element (CPE) circuit were used to describe the impedance spectroscopy, and excellent agreement between the calculated and measured curves was obtained in the CPE circuit. The resistance and capacitance of the grains and grain boundaries can be tuned by changing the annealing atmosphere and temperature. Under oxygen-absent annealing atmosphere, the electric resistances of the grain boundaries changed greatly but the resistance of the grains has almost no change. While under oxygen annealing atmosphere, the reverse happened. On the basis of this result, it is demonstrated that the origin of the semiconductivity of the grains in CCTO polycrystalline films arises from their oxygen-loss...

Large Grain Size Dependence of Resistance of Polycrystalline Films

Arun, P.; Tyagi, Pankaj; Vedeshwar, A. G.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 05/06/2003
Relevância na Pesquisa
26.53%
A qualitative behavior of grain size dependent resistance of polycrystalline films has been worked out by extending the earlier model (Volger's model) for polycrystalline films. Growth of grain size is considered to be accompanied with a decrease in the number of grains present. The variation of the number of grains is restricted along one direction at a time, assuming it to be constant along the other two directions, to simplify the problem. Combining the results along film thickness and film length, the calculated resistance versus grain size shows a family of curves. These curves can be used to know the growth direction by comparing the measured grain size dependence of the resistance.; Comment: PDF file 17 pages

Mesoscale theory of grains and cells: crystal plasticity and coarsening

Limkumnerd, Surachate; Sethna, James P.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.3%
Solids with spatial variations in the crystalline axes naturally evolve into cells or grains separated by sharp walls. Such variations are mathematically described using the Nye dislocation density tensor. At high temperatures, polycrystalline grains form from the melt and coarsen with time: the dislocations can both climb and glide. At low temperatures under shear the dislocations (which allow only glide) form into cell structures. While both the microscopic laws of dislocation motion and the macroscopic laws of coarsening and plastic deformation are well studied, we hitherto have had no simple, continuum explanation for the evolution of dislocations into sharp walls. We present here a mesoscale theory of dislocation motion. It provides a quantitative description of deformation and rotation, grounded in a microscopic order parameter field exhibiting the topologically conserved quantities. The topological current of the Nye dislocation density tensor is derived from a microscopic theory of glide driven by Peach-Koehler forces between dislocations using a simple closure approximation. The resulting theory is shown to form sharp dislocation walls in finite time, both with and without dislocation climb.; Comment: 5 pages, 3 figures

Control and Characterization of Individual Grains and Grain Boundaries in Graphene Grown by Chemical Vapor Deposition

Yu, Qingkai; Jauregui, Luis A.; Wu, Wei; Colby, Robert; Tian, Jifa; Su, Zhihua; Cao, Helin; Liu, Zhihong; Pandey, Deepak; Wei, Dongguang; Chung, Ting Fung; Peng, Peng; Guisinger, Nathan; Stach, Eric A.; Bao, Jiming; Pei, Shin-shem; Chen, Yong P.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
26.61%
The strong interest in graphene has motivated the scalable production of high quality graphene and graphene devices. Since large-scale graphene films synthesized to date are typically polycrystalline, it is important to characterize and control grain boundaries, generally believed to degrade graphene quality. Here we study single-crystal graphene grains synthesized by ambient CVD on polycrystalline Cu, and show how individual boundaries between coalescing grains affect graphene's electronic properties. The graphene grains show no definite epitaxial relationship with the Cu substrate, and can cross Cu grain boundaries. The edges of these grains are found to be predominantly parallel to zigzag directions. We show that grain boundaries give a significant Raman "D" peak, impede electrical transport, and induce prominent weak localization indicative of intervalley scattering in graphene. Finally, we demonstrate an approach using pre-patterned growth seeds to control graphene nucleation, opening a route towards scalable fabrication of single-crystal graphene devices without grain boundaries.; Comment: New version with additional data. Accepted by Nature Materials

Mechanical properties of polycrystalline graphene based on a realistic atomistic model

Kotakoski, Jani; Meyer, Jannik C.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
26.53%
Graphene can at present be grown at large quantities only by the chemical vapor deposition method, which produces polycrystalline samples. Here, we describe a method for constructing realistic polycrystalline graphene samples for atomistic simulations, and apply it for studying their mechanical properties. We show that cracks initiate at points where grain boundaries meet and then propagate through grains predominantly in zigzag or armchair directions, in agreement with recent experimental work. Contrary to earlier theoretical predictions, we observe normally distributed intrinsic strength (~ 50% of that of the mono-crystalline graphene) and failure strain which do not depend on the misorientation angles between the grains. Extrapolating for grain sizes above 15 nm results in a failure strain of ~ 0.09 and a Young's modulus of ~ 600 GPa. The decreased strength can be adequately explained with a conventional continuum model when the grain boundary meeting points are identified as Griffith cracks.; Comment: Accepted for Physical Review B; 5 pages, 4 figures

Inter comparison of the magneto transport of La2/3Ca1/3MnO3: Ag/In polycrystalline composites

Tripathi, Rahul; Awana, V. P. S.; Balamurugan, S.; Kotnala, R. K.; RamKishore; Kishan, H.; Takayama-Muromachi, E.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 09/05/2007
Relevância na Pesquisa
26.53%
In this article, we report the synthesis, magneto transport features, and magnetization of polycrystalline La2/3Ca1/3MnO3:Agx/Inx composites with x = 0, 0.1, 0.2, 0.3 and 0.4. In case of Ag the temperature coefficient of resistance (TCR) near ferromagnetic (FM) transition enhances significantly with addition of Ag. The FM transition temperature (TFM) is also increased slightly with Ag doping. Magneto-transport measurements revealed that magneto-resistance (MR) is found to be maximum near TFM. Very sharp TCR is seen near TFM with highest value of up to 15 % for Ag (0.4) sample, which is an order of magnitude higher than as for pristine sample and is the best value yet reported for any polycrystalline LCMO compound. Increased TCR, TFM and significant above room temperature MR of La2/3Ca1/3MnO3:Agx composites is explained on the basis of improved grains size. Interestingly the La2/3Ca1/3MnO3:Inx composites behaved exactly in opposite way resulting in decreased TFM, and TCR compared to pristine LCMO compound. In fact the grains morphology of LCMO:Inx composites is seen inferior to pristine LCMO which is opposite to the LCMO:Agx case.; Comment: 13 pages of TEXT+Figs

The role of silver addition on the structural and superconducting properties of polycrystalline Sr0.6K0.4Fe2As2

Wang, Lei; Qi, Yanpeng; Zhang, Xianping; Gao, Zhaoshun; Wang, Dongliang; Ma, Yanwei
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
26.51%
The effect of Ag addition (0-20 wt%) on polycrystalline Sr0.6K0.4Fe2As2 superconductor has been investigated. It is found that the critical transition temperature Tc was not depressed, and the irreversibility field Hirr and hysteresis magnetization were significantly enhanced upon Ag addition. Characterization study reveals that larger grains are observed in the Ag-added samples. Moreover, the formation of glassy phase as well as amorphous layer, which are present in almost all the grain edges and boundaries in pure samples, are suppressed by Ag addition. The improvement of superconducting properties in Ag-added samples may originate from the enlargement of grains as well as better connections between grains; Comment: 17 pages, 7 figures. Supercond. Sci. Technol.,accepted

Effect of grain shape on the agglomeration of polycrystalline thin films

Bouville, Mathieu
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 03/10/2006
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26.53%
Grain-boundary grooving is a general phenomenon occurring in all polycrystalline materials at the intersection between the grain-boundary and the interface or free surface. It has been studied theoretically for some time. Grain-boundary grooving in the context of faceted interfaces in particular has attracted some attention. However, these works did not consider the case of thin films and the consequences on agglomeration of the shape of the interface. In this Letter, we compare the agglomeration of thin films with rounded and faceted interfaces. The shape of the grains can dramatically affect the agglomeration of polycrystalline thin films by grain-boundary grooving. Anisotropy plays a central role in the stability against agglomeration of faceted films. Even a small difference between the interface energies of the facets can destabilize faceted grains or, on the contrary, it can make them perfectly stable at any thickness. keywords: grain-boundary grooving, dihedral angle, faceting, energy, silicide, theory, model.; Comment: 3 pages, 3 figures

Dislocation velocity in single and polycrystalline silicon-iron

Moon, D. W.; Vreeland, T., Jr.
Fonte: Instituto de Tecnologia da Califórnia Publicador: Instituto de Tecnologia da Califórnia
Tipo: Article; PeerReviewed Formato: application/pdf
Publicado em 15/02/1968
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26.53%
The stress dependence of screw-dislocation velocity in single and polycrystalline specimens of an iron-3.14% silicon alloy was measured by observation of slip-band growth. An electrolytic etching technique was used to reveal dislocation intersections with the specimen surface, and slip bands were observed to form from fresh scratches and from grain boundaries as a result of pulse loading. Screw dislocation velocity on the {110} 111 system in single crystals at room temperature followed the relation ΰ = (τ/τ0)n, where n = 30.1. A plot of screw-dislocation velocity vs nominal resolved shear stress in individual grains of polycrystalline specimens shows considerable scatter which is attributed to the effects of stress variations due to elastic anisotropy. Observation of slip-band growth in scatched and unscratched grains indicates that the stress required to activate grain boundary sources is greater than the stress required to propagate fresh dislocations.

Dislocation Velocity in Single and Polycrystalline Silicon Iron

Moon, D. W.; Vreeland, T., Jr.
Fonte: Instituto de Tecnologia da Califórnia Publicador: Instituto de Tecnologia da Califórnia
Tipo: Report or Paper; PeerReviewed Formato: application/pdf
Publicado em //1963
Relevância na Pesquisa
26.53%
The stress dependence of screw dislocation velocity single and polycrystalline specimens of an iron-3.14% silicon alloy was measured by observation of slip band growth. An electrolytic etching technique was used to reveal dislocation intersections with the specimen surface, and slip bands were observed to form from fresh scratches and from grain boundaries as a result of pulse loading. Screw dislocation velocity on the {110} 〈111〉system in single crystals at room temperature followed the relation ν = (τ/τ_0)^n where n = 30.1. A plot of screw dislocation velocity vs. nominal resolved shear stress in individual grains of polycrystalline specimens shows considerable scatter which is attributed to the effects of stress variations due to elastic anisotropy. Observation of slip band growth in scratched and unscratched grains indicates that the stress required to activate grain boundary sources is greater than the stress required to propagate fresh dislocations.

Roundness in quartz grains from inland and coastal dune sands, Altar Desert, Sonora, Mexico

Kasper-Zubillaga,Juan José
Fonte: Sociedad Geológica Mexicana, A.C. Publicador: Sociedad Geológica Mexicana, A.C.
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 EN
Relevância na Pesquisa
36.77%
A roundness analysis of quartz grains (n=54) from dunes from San Luis Río Colorado (SLRC), El Pinacate (EP), Golfo de Santa Clara (GSC) and Puerto Peñasco (PP), Sonora, Mexico, was carried out in order to determine the provenance of quartz grains and their relationship to different quartz types (monocrystalline quartz with straight/undulose extinction, with inclusions and polycrystalline quartz of plutonic origin and with straight/undulose extinction). Aeolian transport and wind selectiveness produces fine-grained and moderately to well sorted sands in SLRC and EP dune sands whereas medium sand sizes and moderately well sorted sands are present at sites GSC and PP suggesting mixing of aeolian/marine processes that generate different grain sizes of different composition. Roundness of quartz grains at sites SLRC and EP suggests fluvial transport in the Colorado River Delta but also to long aeolian transport. Some quartz grains from the GSC and PP sites showed angular and rounded quartz due to a mix of aeolian/marine processes. Samples from sites SLRC and EP concentrate monocrystalline quartz with straight and undulose extinction derived from a near source sediment. Samples from sites GSC and PP are dominated by monocrystalline quartz with straight and undulose extinction derived from plutonic and low-rank metamorphic rocks. Polycrystalline quartz is derived from plutonic and low-rank metamorphic rocks. Correlations between Mz vs. SA/SR (grain-size...