scholarly journals Laboratory Measurements of Zeta Potential in Fractured Lewisian Gneiss: Implications for the Characterization of Flow in Fractured Crystalline Bedrock

2021 ◽  
Vol 12 (1) ◽  
pp. 180
Author(s):  
Jan Vinogradov ◽  
Miftah Hidayat ◽  
Yogendra Kumar ◽  
David Healy ◽  
Jean-Christophe Comte
Keyword(s):  
Zeta Potential ◽  
Fracture Aperture ◽  
X Ray Diffraction ◽  
Crystalline Bedrock ◽  
Confining Pressures ◽  
Basement Aquifers ◽  
Complex Solutions ◽  
Reported Data ◽  
The Impact

Despite the broad range of interest and possible applications, the controls on the electric surface charge and the zeta potential of gneiss at conditions relevant to naturally fractured systems remain unreported. There are no published zeta potential measurements conducted in such systems at equilibrium, hence, the effects of composition, concentration and pressure remain unknown. This study reports zeta potential values for the first time measured in a fractured Lewisian gneiss sample saturated with NaCl solutions of various concentrations, artificial seawater and artificial groundwater solutions under equilibrium conditions at confining pressures of 4 MPa and 7 MPa. The constituent minerals of the sample were identified using X-ray diffraction and linked to the concentration and composition dependence of the zeta potential. The results reported in this study demonstrate that the zeta potential remained negative for all tested solutions and concentrations. However, the values of the zeta potential of our Lewisian gneiss sample were found to be unique and dissimilar to pure minerals such as quartz, calcite, mica or feldspar. Moreover, the measured zeta potentials were smaller in magnitude in the experiments with artificial complex solutions compared with those measured with NaCl, thus suggesting that divalent ions (Ca2+, Mg2+ and SO42−) acted as potential determining ions. The zeta potential was also found to be independent of salinity in the NaCl experiments, which is unusual for most reported data. We also investigated the impact of fracture aperture on the electrokinetic response and found that surface electrical conductivity remained negligibly small across the range of the tested confining pressures. Our novel results are an essential first step for interpreting field self-potential (SP) signals and facilitate a way forward for characterization of water flow through fractured basement aquifers.

scholarly journals Preparation and Characterization of Spherical Submicron CL-20 by Siphon Spray Refinement

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Jiangtao Xing ◽  
Weili Wang ◽  
Wenzheng Xu ◽  
Tianle Yao ◽  
Jun Dong ◽  
...  
Keyword(s):  
Impact Sensitivity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Crystal Forms ◽  
Refined Method ◽  
Diffraction Angle ◽  
Ultrasonic Assisted ◽  
The Impact ◽  
Thermal Stability Of

In order to improve the safety of hexanitrohexaazaisowurtzitane (CL-20), submicron CL-20 particles were prepared by a siphon ultrasonic-assisted spray refining experimental device. The samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC), and the impact sensitivity of the samples was tested. The results show that the particle size of siphon-refined CL-20 is about 800 nm~1 μm, which is more smooth, mellow, and dense than that of CL-20 prepared by a traditional pressure-refined method. The peak diffraction angle of pressure- and siphon-refined CL-20 is basically the same as that of raw CL-20, and their crystal forms are ε type. The peak strength of pressure- and siphon-refined CL-20 decreased obviously. The apparent activation energy of pressure-refined CL-20 and siphon-refined CL-20 is 13.3 kJ/mol and 11.95 kJ/mol higher than that of raw CL-20, respectively. The thermal stability of CL-20 is improved. The activation enthalpy (ΔH#) is significantly higher than that of raw CL-20, and the characteristic drop is 70.4% and 82.7% higher than that of raw CL-20. The impact sensitivity of siphon-refined CL-20 is lower than that of pressure-refined CL-20, so the safety performance of an explosive is improved obviously.

Preparation by solution mixing and characterization of condensation type poly(dimethyl siloxane)/graphene nanoplatelets composites

2021 ◽  
pp. 002199832110558
Author(s):  
Panayiotis Ketikis ◽  
Efthimios Damopoulos ◽  
Georgios Pilatos ◽  
Panagiotis Klonos ◽  
Apostolos Kyritsis ◽  
...  
Keyword(s):  
Graphene Nanoplatelets ◽  
Matrix Composites ◽  
Dielectric Relaxation Spectroscopy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Melting Temperatures ◽  
Dimethyl Siloxane ◽  
Diffraction Patterns ◽  
The Impact

The impact of the incorporation of graphene nanoplatelets (GN) on the properties of hydroxyl-terminated poly(dimethylsiloxane) (PDMS) matrices was investigated. The composites were prepared by solution mixing, using tetrahydrofuran (THF) as a solvent. Brookfield viscosimetry, implemented during the vulcanization process, revealed that GN increases the viscosity of the system, compared to pristine PDMS, proportionally to its concentration. X-ray diffraction patterns suggested an efficient dispersion of GN in the polysiloxane matrix. The D and G bands ratio (ID/IG) calculation, based on RAMAN spectra of GN/PDMS specimens, revealed more defects in graphene nanoplatelets when incorporated in the PDMS matrix. By differential scanning calorimetry (DSC), a marginal increase in crystallization, glass transition and melting temperatures of PDMS in GN/PDMS composites was observed. Improvement of the thermal stability of LMW PDMS composites, especially for higher GN concentrations (3 and 5 phr), was noticed by thermogravimetric analysis (TGA). Additionally, GN enhanced the tensile strength of composites, up to 73% for the 3 phr GN/LMW PDMS composite. A significant increase in the elongation at break was recorded, whereas no effect on the modulus of elasticity was recorded. The decrease in toluene-swelling, for the LMW PDMS matrix composites, was attributed to the increase in the tortuosity path because of the efficient dispersion of GN. A decrease in oxygen permeability of 55–65% and 44–58% was measured in membranes made of PDMS composites containing 0.5 phr and 1 phr GN, respectively. Dielectric relaxation spectroscopy (DRS) measurements recorded a significant increase in the conductivity of the higher graphene content composites.

Imidazole-containing Bispidine Ligands: Synthesis, Structure and Cu(II) Complexation

2011 ◽  
Vol 66 (7) ◽  
pp. 721-728 ◽  
Author(s):  
Martin Walther ◽  
Madlen Matterna ◽  
Stefanie Juran ◽  
Silke Fähnemann ◽  
Holger Stephan ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Enol Form ◽  
Trans Configuration ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Impact ◽  
Configurational Isomerism

The preparation and characterization of tris-pyridyl bispidine (3,7-diazabicyclo[3.3.1]nonane) derivatives with benzimidazole and imidazole donor groups at the N-3 position of the bispidine skeleton and their copper(II) complexes are reported. The impact of the hetaryl substituents on the configurational isomerism of piperidones and their corresponding bispidones has been studied by NMR spectroscopy, revealing the exclusive appearance in the enol form for the piperidones in solution and the trans-configuration regarding the two pyridyl substituents, as well as the sole formation of the unsymmetric exo-endo isomers for the corresponding bispidones. Thus, the bispidones are preorganized ligands for building pentacoordinated complexes, confirmed by the preparation and characterization of the corresponding Cu(II) complexes. Of the di-pyridyl piperidones with benzimidazole and imidazole substituents, and of the Cu(II) complex of the benzimidazole-containing bispidone, crystals have become available for the analysis by X-ray diffraction, showing that the piperidones form the enol tautomers also in the solid state.

Synthesis and Characterization of Pd/Ag/SiO2 Nano-Composite Materials

2017 ◽  
Vol 726 ◽  
pp. 204-209 ◽  
Author(s):  
Jing Yang ◽  
Bao Song Li ◽  
Zhi Tong ◽  
Rui Hua Mu
Keyword(s):  
Zeta Potential ◽  
Size Distribution ◽  
Sol Gel ◽  
Linear Structure ◽  
Nitrogen Atmosphere ◽  
Molar Ratio ◽  
Powder Materials ◽  
X Ray Diffraction ◽  
Silica Network

Pd/Ag/SiO2 sols and powder materials were prepared by adding AgNO3 and Pd (NO3)2·2H2O into a methyl-modified silica sol. Tetraethylorthosilicate and methyltriethoxysilane were used as the silica precursor for the sol-gel reaction. The obtained SiO2 sols and powder materials were characterized by sol particle size distribution, zeta potential analysis, UV-Vis spectra, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) measurement. It was found that most of the particle sizes of the prepared Pd/Ag/SiO2 sols are about 2~10 nm with narrow size distribution. The zeta potential of Pd/Ag/SiO2 sol with Pd/Ag molar ratio of 7.5/2.5 presents the highest value. The FTIR analysis substantiates that the Si-CH3 groups exist in the silica network and the formed Pd/Ag/SiO2 sol particles possess linear structure. XRD characterization indicates that the Pd2+ and Ag+ in the Pd/Ag/SiO2 materials had be reduced to Pd0 and Ag0, respectively, after annealed in a nitrogen atmosphere at 350°C.

Synthesis and Characterization of Nanocrystalline Ba-doped Mn3O4 Hausmannite Thin Films for Optoelectronic Applications

2021 ◽  
Author(s):  
Aus A. Najim ◽  
Kadhim R. Gbashi ◽  
Ammar T. Salih
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Structural Characteristics ◽  
Optical Transmittance ◽  
Degree Of Crystallinity ◽  
Chemical Spray Pyrolysis ◽  
X Ray Diffraction ◽  
Glass Substrates ◽  
The Impact

In the present work, nanocrystalline hausmannite Mn3O4:Ba thin films have been deposited on glass substrates by chemical spray pyrolysis (CSP). Then, we investigated the impact of Ba doping concentrations on the structural, morphological and optical properties. The structural characteristics were investigated by X-ray diffraction technique and clearly show the films have a spinel Mn3O4 polycrystalline structure, the degree of crystallinity was improved by increasing Ba concentrations in Mn3O4 matrix with crystallite size range of 15–33[Formula: see text]nm. The lattice parameters, the unit cell volume and the (Mn-O) bond length of tetrahedral and octahedral sites, were varied by increasing Ba concentrations. SEM micrographs show that the films are homogeneous with nanoparticles dispersed on the surface with sizes range 30–132[Formula: see text]nm. The optical properties were estimated by UV-Vis-NIR spectrophotometer and exhibited that the optical transmittance and band gap were improved by increasing Ba doping concentration. Empirical equations were suggested to estimate some correlated variables with excellent agreement with the experimental data. The optimum condition was recorded in films doped with 3% of Ba where a better crystallinity, a preferable surface morphology and outstanding optical properties have been achieved.

scholarly journals Cu(I) Arylsulfonate π-Complexes with 3-Allyl-2-thiohydantoin: The Role of the Weak Interactions in Structural Organization

2020 ◽  
Vol 67 (4) ◽  
pp. 1148-1154
Author(s):  
Andrii Fedorchuk ◽  
Evgeny Goreshnik ◽  
Yurii Slyvka ◽  
Marian Mys’kiv
Keyword(s):  
Coordination Compounds ◽  
Structural Organization ◽  
Weak Interactions ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Coordination Environment ◽  
X Ray ◽  
The Impact

The present work is directed toward preparation and structural characterization of two novel Cu(I) arylsulfonate π-complexes with 3-allyl-2-thiohydantoin, namely [Cu2(Hath)4](C6H5SO3)2 (1) and [Cu2(Hath)4](p-CH3C6H4SO3)2 · 2H2O (2) (Hath = 3-allyl-2-thiohydantoin), obtained by the means of alternating current electrochemical synthesis and studied with X-ray diffraction method. In both structures, the inner coordination sphere is represented by the cationic dimer [Cu2(Hath)4]2+ with one crystallographically independent copper(I) atom which has a trigonal pyramidal coordination environment formed by three Hath thiogroup S atoms and double C=C bond of its allyl group. [Cu2(Hath)4]2+ fragments in both coordination compounds are very similar, despite some divergences such as a big difference in Cu−S distance to the apical S atom (3.0374(8) Å in 1 and 2.7205(9) Å in 2). This difference was explained by the impact of the system of weak interactions, which are quite different.

Effect of Zinc Oxide Nanoparticle Sizes on Viscosity of Nanofluid for Application in Enhanced Oil Recovery

2016 ◽  
Vol 38 ◽  
pp. 36-39 ◽  
Author(s):  
Kean Chuan Lee ◽  
Zulhilmi Akmal bin Saipolbahri ◽  
Hassan Soleimani ◽  
Hasnah Mohd. Zaid ◽  
Beh Hoe Guan ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Oil Recovery ◽  
Sol Gel ◽  
Zno Nanoparticle ◽  
X Ray Diffraction ◽  
Organic Precursor ◽  
Transmission Electron ◽  
The Impact ◽  
Nanoparticle Sizes

Zinc oxide (ZnO) with different nanoparticle (NP) sizes was prepared and synthesized by using the sol-gel method with organic precursor, followed by the characterization of the ZnO nanoparticle by using X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) to identify the effect of nanoparticle sizes of ZnO on the viscosity of the nanofluid. The impact of nanoparticle sizes on EOR was investigated. Results showed both viscosity and interfacial tension (IFT) increased with the nanoparticle size.

scholarly journals Effect of Nitric Acid Concentrations on Synthesis and Stability of Maghemite Nanoparticles Suspension

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Irwan Nurdin ◽  
Mohd Rafie Johan ◽  
Iskandar Idris Yaacob ◽  
Bee Chin Ang
Keyword(s):  
Nitric Acid ◽  
Zeta Potential ◽  
Narrow Particle Size Distribution ◽  
Maghemite Nanoparticles ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Stability ◽  
Xrd Patterns ◽  
Nanoparticles Suspension

Maghemite(γ-Fe2O3)nanoparticles have been synthesized using a chemical coprecipitation method at different nitric acid concentrations as an oxidizing agent. Characterization of all samples performed by several techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM), alternating gradient magnetometry (AGM), thermogravimetric analysis (TGA), dynamic light scattering (DLS), and zeta potential. The XRD patterns confirmed that the particles were maghemite. The crystallite size of all samples decreases with the increasing concentration of nitric acid. TEM observation showed that the particles have spherical morphology with narrow particle size distribution. The particles showed superparamagnetic behavior with decreased magnetization values at the increasing concentration of nitric acid. TGA measurement showed that the stability temperature decreases with the increasing concentration of nitric acid. DLS measurement showed that the hydrodynamic particle sizes decrease with the increasing concentration of nitric acid. Zeta potential values show a decrease with the increasing concentration of nitric acid. The increasing concentration of nitric acid in synthesis of maghemite nanoparticles produced smaller size particles, lower magnetization, better thermal stability, and more stable maghemite nanoparticles suspension.

A Study of Structural Defects in 3C-SiC Hetero-Epitaxial Films

2010 ◽  
Vol 645-648 ◽  
pp. 371-374 ◽  
Author(s):  
Andrea Severino ◽  
Ruggero Anzalone ◽  
Corrado Bongiorno ◽  
Francesco La Via
Keyword(s):  
Epitaxial Films ◽  
Structural Defects ◽  
Defect Characterization ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Pole Figures ◽  
The Impact ◽  
Sic Films

A wide characterization of crystalline defects involved in the 3C-SiC heteroepitaxy on Si is here presented. The aim of this work is to show how analysis techniques, such as transmission electron microscopy (TEM) and x-ray diffraction (XRD), can help the researcher in the study of structural defects. The work is focused on stacking faults and microtwins since both of them influence the atomic stacking along the {111} 3C-SiC planes. Their distinction can indeed be troublesome. It will be shown that TEM can be helpful, by choosing a determined zone axis of observation, for defect characterization and distinction. Moreover, the impact of microtwins on the crystal quality of 3C-SiC films is studied by performing XRD pole figures. By means of this technique and simulations, we found that the <111> direction of the SiC crystal is not aligned to the <110> Si direction, but it is shifted of 3.5° along the <002> Si direction, due to second-order twinnings in the 3C-SiC crystal.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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