Study on Microstructure Differences of Coal Samples before and after Loading

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Jiajia Liu ◽  
Yingxiang Fang ◽  
Gaini Jia ◽  
Shouqi Chen ◽  
Jianmin Hu
Keyword(s):  
Electron Microscopy ◽  
Coal Seam ◽  
Coal Sample ◽  
Coal Seam Gas ◽  
Adsorbed Gas ◽  
Transmission Electron ◽  
Parallel Layer ◽  
Before And After ◽  
Spectrum Area ◽  
Nmr Techniques

The microscopic pore structure of coal affects the content of adsorbed gas. The microstructure of coal sample before and after loading is different, which will affect the adsorption and permeability of coal seam gas. In order to study this difference, the authors carried out mercury intrusion experiments on coal containing different coal samples and used nondestructive nuclear magnetic resonance (NMR) techniques, scanning electron microscopy, and transmission electron microscopy, to study the microstructure of coal samples before and after loading. The experimental results show that the pores of coal samples are mainly micropores and small pores, and the mesopores and macropores are relatively few. The T2 spectrum area of the coal sample is significantly increased after loading, and the parallel-layer coal samples’ T2 spectrum area is 46735, which is 9112 more than the vertical layer coal samples. The T2 spectrum of the vertical coalbed of saturated water samples shows a three-peak shape, the peak of the T2 spectrum is 12692, and the parallel bedding shows a bimodal morphology. The peak area of the T2 spectrum is 11277. The permeability of the parallel bedding coal sample is good, and the coal sample exhibits anisotropic properties. The pores and cracks of the coal samples increased after loading, and the localized area of the coal sample collapsed and formed a fracture zone, which was not conducive to the occurrence of coal seam gas. Further explanation of the changes in the permeability of the coal sample before and after loading will affect the gas storage and transportation.

scholarly journals Polystyrene/Montmorillonite Nanocomposites: Study of the Morphology and Effects of Sonication Time on Thermal Stability

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Mashael Alshabanat ◽  
Amal Al-Arrash ◽  
Waffa Mekhamer
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Solution Method ◽  
Sonication Time ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Polystyrene Matrix ◽  
Before And After ◽  
Silicate Layers ◽  
Thermal Stability Of

Polymer nanocomposites of polystyrene matrix containing 10% wt of organo-montmorillonite (organo-MMT) were prepared using the solution method with sonication times of 0.5, 1, 1.5, and 2 hours. Cetyltrimethylammonium bromide (CTAB) is used to modify the montmorillonite clay after saturating its surface with Na+ions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the montmorillonite before and after modification by CTAB. The prepared nanocomposites were characterized using the same analysis methods. These results confirm the intercalation of PS in the interlamellar spaces of organo-MMT with a very small quantity of exfoliation of the silicate layers within the PS matrix of all samples at all studied times of sonication. The thermal stability of the nanocomposites was measured using thermogravimetric analysis (TGA). The results show clear improvement, and the effects of sonication time are noted.

scholarly journals Modification of Titanium Dioxide Nanoparticles with 3-(Trimethoxysilyl)propyl Methacrylate Silane Coupling Agent

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Thuy-Chinh Nguyen ◽  
Tien-Dung Nguyen ◽  
Duc-Toan Vu ◽  
Duc-Phuong Dinh ◽  
Anh-Hiep Nguyen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Tio2 Nanoparticles ◽  
Coupling Agent ◽  
Titanium Dioxide Nanoparticles ◽  
X Ray Diffraction ◽  
Nano Tio2 ◽  
Propyl Methacrylate ◽  
Transmission Electron ◽  
Before And After ◽  
Modification Of Titanium

This paper presents some characteristics, properties, and morphology of TiO2 nanoparticles (nano-TiO2) modified with various contents of 3-(trimethoxysilyl)propyl methacrylate (TMSPM) coupling agent. The treatment process was carried out in ethanol solvent at 50oC using ammonia as a catalyst for hydrolysis reaction of silane to silanol. Infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, field emission scanning electron microscopy, dynamic light scattering, ultraviolet-visible spectroscopy, and X-ray diffraction methods were used for determination of the characteristics, properties of nano-TiO2 before and after treatment. In addition, the contact angle and grafting efficiency of TMSPM on the surface of TiO2 nanoparticles was also evaluated. The obtained results confirmed that TMSPM was grafted to the TiO2 nanoparticles, the agglomeration of nano-TiO2 was decreased, and surface of TiO2 nanoparticles became hydrophobic after modification by TMSPM.

scholarly journals Barium-Encapsulated Biodegradable Polycaprolactone for Sulfate Removal

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1789
Author(s):  
Changseok Han ◽  
Mallikarjuna Nadagouda
Keyword(s):  
Electron Microscopy ◽  
Barium Carbonate ◽  
High Capacity ◽  
Small Scale ◽  
Ohio River ◽  
Sulfate Removal ◽  
Transmission Electron ◽  
Before And After ◽  
High Resolution Tem ◽  
The Media

Various compositions of barium carbonate (BaCO3) loaded polycaprolactone (PCL) composites were prepared, including 2.5/97.5, 10/90, 30/70, 50/50 and 90/10 (PCL/BaCO3), via re-precipitation technique. Small-scale column tests were conducted to study the efficiency of sulfate removal using the PCL/BaCO3 composites. The composites before and after their use to remove sulfate were extensively characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), high-resolution TEM (HR-TEM), and thermogravimetric analysis (TGA). As PCL is a biodegradable polymer, these composites are environmentally friendly and have several advantages over barium sulfate precipitation in overcoming clogging issues in filters or resins due to collection of natural organic matter (NOM). The media used in this study exhibited high capacity and was able to remove more than 90% sulfate from synthetic sulfate containing waters and NOM samples collected from the Ohio River.

scholarly journals Endothelium-derived hyperpolarizing factor in preeclampsia: heterogeneous contribution, mechanisms, and morphological prerequisites

2008 ◽  
Vol 294 (2) ◽  
pp. R510-R519 ◽  
Author(s):  
Leanid Luksha ◽  
Henry Nisell ◽  
Natallia Luksha ◽  
Marius Kublickas ◽  
Kjell Hultenby ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Subcutaneous Fat ◽  
Normal Pregnancy ◽  
Transmission Electron ◽  
Main Pathway ◽  
Before And After ◽  
Group 2 ◽  
Cytochrome P 450 ◽  
Group 1

We hypothesized that in preeclampsia (PE), contribution of endothelium-derived hyperpolarizing factor (EDHF) and the mechanism/s of its action differ from that in normal pregnancy (NP). We aimed to assess endothelial function and morphology in arteries from NP and PE with particular focus on EDHF. Arteries (≈200 μm) were dissected from subcutaneous fat biopsies obtained from women undergoing cesarean section. With the use of wire myography, responses to the endothelium-dependent agonist bradykinin (BK) were determined before and after inhibition of pathways relevant to EDHF activity. The overall responses to BK in arteries from PE ( n = 13) and NP ( n = 17) were similar. However, in PE, EDHF-mediated relaxation was reduced ( P < 0.05). All women within the PE group were divided into two subgroups: with more ( group 1) or less ( group 2) than 50% reduction of EDHF-typed responses after 18-α-glycyrrhetinic acid (an inhibitor of myoendothelial gap junctions, MEGJs). The division showed that 1) MEGJs are principally involved when the EDHF contribution is reduced; and 2) when the EDHF contribution is similar to that in NP, the H2O2 and/or cytochrome P-450 epoxygenase products of arachidonic acid (AA), along with MEGJs, confer EDHF-mediated relaxation. In contrast, MEGJs were the main pathway for EDHF in NP. The abundant presence of MEGJs in arteries from NP but deficiency of them in PE was observed using transmission electron microscopy. We conclude that PE is associated with heterogeneous contribution of EDHF, and the mechanism behind EDHF-typed responses is mediated either by MEGJs alone or in combination with H2O2 or cytochrome P-450 epoxygenase metabolites of AA.

Synthesis and Characterization of Porous Mo-W Oxide Nanostructures

2008 ◽  
Vol 8 (12) ◽  
pp. 6445-6450
Author(s):  
F. Paraguay-Delgado ◽  
Y. Verde ◽  
E. Cizniega ◽  
J. A. Lumbreras ◽  
G. Alonso-Nuñez
Keyword(s):  
Electron Microscopy ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Synthesis Method ◽  
Atomic Ratio ◽  
High Specific Surface Area ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Before And After

The present study reports the synthesis method, microstructure characterization, and thermal stability of nanostructured porous mixed oxide (MoO3-WO3) at 550 and 900 °C of annealing. The material was synthesized using a hydrothermal method. The precursor was prepared by aqueous solution using ammonium heptamolibdate and ammonium metatungstate, with an atomic ratio of Mo/W = 1. The pH was adjusted to 5, and then the solution was transferred to a teflon-lined stainless steel autoclave and heated at 200 °C for 48 h. The resultant material was washed using deionized water. The specific surface area, morphology, composition, and microstructure before and after annealing were studied by N2 physisorption, scanning electron microscopy (SEM), analytical transmission electron microscopy (TEM), and X-Ray diffraction (XRD). The initial synthesized materials showed low crystallinity and high specific surface area around (141 m2/g). After thermal annealing the material showed higher crystallinity and diminished its specific surface area drastically.

Preparation of Cellulose Acetate Ultra-Fine Fibers Containing Quasi-Spherical Gold Nanoparticles by Electrospinning Method

2011 ◽  
Vol 391-392 ◽  
pp. 400-403
Author(s):  
Dong Mei Zhao ◽  
Li Guo Sun ◽  
Li Li Lv ◽  
Jian Li
Keyword(s):  
Electron Microscopy ◽  
Gold Nanoparticles ◽  
Cellulose Acetate ◽  
Trisodium Citrate ◽  
X Ray Diffraction ◽  
Au Nps ◽  
Transmission Electron ◽  
Electrospinning Method ◽  
Before And After ◽  
Spherical Gold Nanoparticles

Quasi-spherical gold nanoparticles(Au NPs) prepared by trisodium citrate reduction of HAuCl4were dispersed into cellulose acetate(CA) ultra-fine fibers by electrospinning. The optical properties of Au NPs before and after electrospinning were measured by UV-vis spectrometer. The morphology and distribution of Au NPs in CA ultra-fine fibers were observed by transmission electron microscopy (TEM). The morphology and diameter of Au NPs/CA fibers were studied by scanning electron microscopy (SEM). The crystallinity change of CA fiber before and after adding Au NPs was characterized by X-ray diffraction (XRD).

Phase Composition and Defect Substructure of the Zirconia Nanopowder Modified by the Powerful Ultrasonic Assistance

2013 ◽  
Vol 872 ◽  
pp. 180-183
Author(s):  
Oleg L. Khasanov ◽  
Yury F. Ivanov ◽  
Edgar S. Dvilis ◽  
Oleg S. Tolkachev
Keyword(s):  
Electron Microscopy ◽  
Phase Composition ◽  
Stabilized Zirconia ◽  
Polycrystalline Structure ◽  
Random Orientation ◽  
Ultrasonic Action ◽  
Defect Substructure ◽  
Cubic Phases ◽  
Transmission Electron ◽  
Before And After

Commercial nanopowder of the partially yttrium-stabilized zirconia (ZrO2+3 mol.% Y2O3) was treated by the non-cavitational powerful ultrasonic action (PUA). Influence of PUA on the microstructure and phase composition of the powder has been investigated by scanning and transmission electron microscopy. Investigated powder before and after PUA has polycrystalline structure. It was found that TZ-3YS particles after PU-treatment have tetragonal and cubic zirconia phases; some of the particles consist of a mixture of monoclinic, tetragonal and cubic phases, but these particles have substructure with random orientation of fragments.

Characterization of Ni-P and Ni-P-Al2O3 Heat Treated Layers

2017 ◽  
Vol 1143 ◽  
pp. 26-31
Author(s):  
Lucica Balint ◽  
Gina Genoveva Istrate
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Corrosion Resistance ◽  
Composite Coatings ◽  
Treatment Temperature ◽  
Initial State ◽  
X Ray ◽  
Transmission Electron ◽  
Heat Treated ◽  
Before And After

Research has shown the relationship among hardness, usage and corrosion resistance Ni-P-Al2O3 composite coatings on steel support heat treated. The electroless strips were heat treated at 200°C, 300°C, 400°C, 500°C and 600°C. Further studies on corrosion, hardness and usage revealed changes in properties, compared to the initial state, both on the strips coated with Ni-P and the ones coated with Ni-P-Al2O3 composite. The samples have been studied before and after the heat treatment via Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Analysis (EDX) and X-Ray Diffraction (XRD). The results show that untreated Ni-P layers exhibit strong corrosion resistance, while hardness and usage increase with heat treatment temperature, with a peak at 400 °C. Using suspended particles co-deposition, led to new types of layers, some with excellent hardness and usage properties. Corrosion resistance increase with heat treatment. Coating layers can be adjusted to the desired characteristics, by selecting proper parameters for the expected specific results.

Reactive Multilayers Examined by HRTEM and Plasmon EELS Chemical Mapping

2009 ◽  
Vol 15 (1) ◽  
pp. 54-61 ◽  
Author(s):  
M.A. Mat Yajid ◽  
G. Möbus
Keyword(s):  
Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Peak Position ◽  
Multilayer System ◽  
Chemical Mapping ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Before And After ◽  
Relationship Of ◽  
Electron Energy Loss

AbstractWe examine chemical mapping of reaction phases in a Cu-Al multilayer system using low-loss electron energy loss spectroscopy spectrum imaging and image spectroscopy techniques. The sensitivity of the plasmon peak position and shape to various crystal structures and phases is exploited using postprocessing of spectra into second derivative plasmon maps and line scans. Analytical transmission electron microscopy is complemented by studies of the orientation relationship of the multilayer system using high-resolution electron microscopy of interfaces and selected area diffraction. The techniques have been applied to the Cu-Al multilayer sample and sharply bound epitaxial phases are found, before and after heat treatment.

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