Nano-mechanical Properties and Pore-Scale Characterization of Different Rank Coals

ABSTRACT Characterization of coal micro-structure and the associated rock mechanical properties are of key importance for coal seam exploration, coal bed methane development, enhanced coal bed methane production and CO2 storage in deep coal seams. Considerable knowledge exists about coal chemical properties, but less is known about the nanoscale to the micro-scale structure of coals and how they change with coal strength across coal ranks. Thus, in this study, 3D X-ray micro-computed tomography (with a voxel size of 3.43 µm) and nano-indentation tests were conducted on coal samples of different ranks from peat to anthracite. The micro-structure of peats showed a well-developed pore system with meso- and micro-pores. The meso-pores essentially disappear with increasing rank, whereas the micro-pores persist and then increase past the bituminous rank. The micro-fracture system develops past the peat stage and by sub-bituminous ranks and changes into larger and mature fracture systems at higher ranks. The nano-indentation modulus showed the increasing trend from low- to high-rank coal with a perfect linear relationship with vitrinite reflectance and is highly correlated with carbon content as expected.

Download Full-text

Preparation and characterization of low-cost high-performance mullite-quartz ceramic proppants for coal bed methane wells

Science and Engineering of Composite Materials ◽

10.1515/secm-2017-0142 ◽

2018 ◽

Vol 25 (5) ◽

pp. 957-961 ◽

Cited By ~ 3

Author(s):

Kaiyue Wang ◽

Huijun Wang ◽

Yi Zhou ◽

Guomin Li ◽

Yaqiao Wu ◽

...

Keyword(s):

High Performance ◽

Sintering Temperature ◽

Raw Materials ◽

Low Cost ◽

Quartz Ceramic ◽

Coal Bed ◽

Coal Bed Methane ◽

Sintering Process ◽

Flow Mechanism

AbstractIn this study, the mullite-quartz-based proppants were successfully prepared by using the coal gangue as the raw materials. Then, the effects of the additive and the sintering temperature on the composition, microstructure, and properties of the proppants were investigated. Results showed that the proppants sintered at 1250°C with the 10 wt% bauxite additive presented the best performance, which was very close to that of the quartz-proppant, and met the operational requirements of the 52 MPa coal bed methane wells. The viscous flow mechanism of the liquid phase formed during the sintering process also promoted the arrangement of the grains, thus benefiting the densification and the strength of the proppants.

Download Full-text

Evaluation of the Degree of Conversion, Residual Monomers and Mechanical Properties of Some Light-Cured Dental Resin Composites

Materials ◽

10.3390/ma12132109 ◽

2019 ◽

Vol 12 (13) ◽

pp. 2109 ◽

Cited By ~ 10

Author(s):

Marioara Moldovan ◽

Robert Balazsi ◽

Andrada Soanca ◽

Alexandra Roman ◽

Codruta Sarosi ◽

...

Keyword(s):

Mechanical Properties ◽

Chemical Properties ◽

Degree Of Conversion ◽

Resin Composites ◽

Mechanical Parameters ◽

Dental Resin ◽

Posterior Teeth ◽

Commercial Resin ◽

Diametral Tensile Strength

The novelty of this study consists in the formulation and characterization of three experimental dental composites (PM, P14M, P2S) for cervical dental lesion restoration compared to the commercial composites Enamel plus HRi® - En (Micerium S.p.A, Avengo, Ge, Italy), G-ænial Anterior® - Ge, (GC Europe N.V., Leuven, Belgium), Charisma® - Ch (Heraeus Kulzer, Berkshire, UK). The physio-chemical properties were studied, like the degree of conversion and the residual monomers in cured samples using FTIR-ATR (attenuated total reflectance) and HPLC-UV (ultraviolet detection), as well as the evaluation of the mechanical properties of the materials. The null hypothesis was that there would be no differences between experimental and commercial resin composites regarding the evaluated parameters. Statistical analysis revealed that water and saliva storage induced significant modifications of all mechanical parameters after three months for all tested materials, except for a few comparisons for each type of material. Storage medium seemed not to alter the values of mechanical parameters in comparison with the initial ones for: diametral tensile strength (DTS-saliva for Ge and PM, compressive strength (CS)-water for Ch, DTS-water and Young’s modulus YM-saliva for P14M and YM-water/ saliva for P2S (p > 0.05). Two of the experimental materials showed less than 1% residual monomers, which sustains good polymerization efficiency. Experimental resin composites have good mechanical properties, which makes them recommendable for the successful use in load-bearing surfaces of posterior teeth.

Download Full-text

Characterization of Coal-Bed Methane Reservoirs, Ignacio- Blanco Fruitland Field, LaPlata County, Colorado: ABSTRACT

AAPG Bulletin ◽

10.1306/522b3a01-1727-11d7-8645000102c1865d ◽

1996 ◽

Vol 80 ◽

Author(s):

W. C. Riese, Walter W. Ring

Keyword(s):

Coal Bed ◽

Coal Bed Methane

Download Full-text

Elemental, microstructural, and mechanical characterization of high gold orthodontic brackets after intraoral aging

Biomedical Engineering / Biomedizinische Technik ◽

10.1515/bmt-2015-0205 ◽

2017 ◽

Vol 62 (1) ◽

Cited By ~ 1

Author(s):

Sepp Hersche ◽

Iosif Sifakakis ◽

Spiros Zinelis ◽

Theodore Eliades

Keyword(s):

Mechanical Properties ◽

Elemental Composition ◽

Orthodontic Brackets ◽

Control Group ◽

Indentation Modulus ◽

Backscattered Electron ◽

Lingual Brackets ◽

Electron Imaging ◽

Martens Hardness

AbstractThe purpose of the present study was to investigate the elemental composition, the microstructure, and the selected mechanical properties of high gold orthodontic brackets after intraoral aging. Thirty Incognito™ (3M Unitek, Bad Essen, Germany) lingual brackets were studied, 15 brackets as received (control group) and 15 brackets retrieved from different patients after orthodontic treatment. The surface of the wing area was examined by scanning electron microscopy (SEM). Backscattered electron imaging (BEI) was performed, and the elemental composition was determined by X-ray EDS analysis (EDX). After appropriate metallographic preparation, the mechanical properties tested were Martens hardness (HM), indentation modulus (E

Download Full-text

Mechanical properties of plasma polymer films: a review

SN Applied Sciences ◽

10.1007/s42452-021-04655-9 ◽

2021 ◽

Vol 3 (6) ◽

Author(s):

Jamerson Carneiro de Oliveira ◽

Aissam Airoudj ◽

Philippe Kunemann ◽

Florence Bally-Le Gall ◽

Vincent Roucoules

Keyword(s):

Mechanical Properties ◽

Polymer Films ◽

Chemical Properties ◽

Plasma Polymer ◽

List Type ◽

Physical And Chemical Properties ◽

Plasma Polymers ◽

Physical And Chemical ◽

And Chemical Properties

Abstract Plasma polymers are micro-, or more commonly, nano-sized coatings that can be deposited on a variety of substrates through different approaches. The versatility of these polymers is incremented by the possibility to use other precursors than conventional polymerization reactions and by potential changes in the polymerization mechanisms according to the intrinsic physical and chemical properties of the plasma. That flexibility offers a fruitful ground to a great range of scientific and engineering fields, but it also brings many challenges for universalization of empirical observations. In this review, the use of different precursors, substrates and changes in plasma external parameters were evaluated as common, but not necessarily ideal nor exhaustive, variables for the analysis of mechanical properties of plasma polymer films. The commonly reported trends are complemented with the exceptions, and a variety of hypothesis drawn by the empirical observations are shown. The techniques and methods used for determining the mechanical properties of plasma polymers, the effect of post-treatments on them and some applications are evaluated. Finally, a general conclusion highlighting the challenges of the field is provided. Article highlights The mechanical properties of plasma polymers are evaluated as a function of selected parameters. The techniques of characterization of mechanical properties of plasma polymers are summarized. A discussion of future and current demands for the analysis of mechanical properties of plasma polymers is done.

Download Full-text

Characterization of the mechanical properties of a claystone by nano-indentation and homogenization

Acta Geotechnica ◽

10.1007/s11440-018-0691-0 ◽

2018 ◽

Vol 13 (6) ◽

pp. 1395-1404 ◽

Cited By ~ 6

Author(s):

Fan Zhang ◽

Hanqun Guo ◽

Dawei Hu ◽

Jian-Fu Shao

Keyword(s):

Mechanical Properties ◽

Nano Indentation

Download Full-text

Effects of micropore structure of activated carbons on the CH4/N2 adsorption separation and the enrichment of coal-bed methane

Clean Energy ◽

10.1093/ce/zkab013 ◽

2021 ◽

Vol 5 (2) ◽

pp. 329-338

Author(s):

Jinhua Zhang ◽

Lanting Li ◽

Qiang Qin

Keyword(s):

Pore Structure ◽

Adsorption Process ◽

Activated Carbons ◽

Chemical Properties ◽

Dynamic Effect ◽

Decisive Role ◽

Coal Bed ◽

Coal Bed Methane ◽

Separation Coefficient ◽

Separation Performance

Abstract In the process of enriching CH4 from coal-bed methane, the separation of CH4/N2 is very difficult to accomplish by an adsorption process due to the similar physico-chemical properties of the two molecules. A series of coconut-shell-based granular activated carbons (GACs) with different pore structures were prepared, which were characterized by different methods. The influence of the pore structure on the separation properties was investigated in detail. The results show that one of the carbons prepared (GAC-3) has high CH4 equilibrium adsorption capacity (3.28 mol·kg–1) at 298 K and equilibrium separation coefficient (3.95). The CH4/N2 separation on the GACs is controlled by adsorption equilibrium as compared with the dynamic effect. Taking the specific surface area, for example, the common characterization index of the pore structure is not enough to judge the separation performance of the GACs. However, the microstructure of carbon materials plays a decisive role for CH4/N2 separation. According to the pore-structure analysis, the effective pore size for the CH4/N2 separation is from 0.4 to 0.9 nm, with the optimum effect occurring in the range of 0.6–0.7 nm, followed by the range of 0.7~0.9 nm. Also, a four-bed vacuum pressure swing adsorption process was adopted to evaluate the performance of GACs for the separation of CH4 from nitrogen.

Download Full-text

Study of CaCO3 Whiskers: Preparation and Applicability in Construction Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.250-253.649 ◽

2011 ◽

Vol 250-253 ◽

pp. 649-656

Author(s):

Jian Qiang Wei ◽

Ming Li Cao

Keyword(s):

Mechanical Properties ◽

Fibrous Material ◽

Construction Materials ◽

Micro Structure ◽

Preparation Methods ◽

Artificial Bones ◽

New Type

As a new type of fibrous material, CaCO3whisker has played an increasingly important role in the fields of instrumentation, polymerscience and artificial bones. In order to give full play to CaCO3whisker’s novel micro structure, excellent mechanical properties and stability, we initially applies it to advanced cement based construction materials. The preparation methods, characterization of CaCO3whisker and its applicability in advanced construction materials were studied thoroughly, based on the latest literatures and our newest research works.

Download Full-text