scholarly journals Experimental Investigation on Strain Changes during CO2 Adsorption of Raw Coal Sample: Temperature and Effective Stress

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 717
Author(s):  
Kai Wang ◽  
Qichao Fu ◽  
Xiang Zhang ◽  
Hengyi Jia
Keyword(s):  
Effective Stress ◽  
Coal Sample ◽  
Adsorption Process ◽  
Co2 Adsorption ◽  
Axial Strain ◽  
Radial Strain ◽  
Experimental System ◽  
Laboratory Simulation ◽  
Axial Deformation ◽  
Adsorption Desorption

Through laboratory simulation experiments, this paper studies the influence of different temperature and stress conditions on strain changes of raw coal samples induced by the CO2 adsorption with tri-axial creep-seepage and adsorption-desorption experimental system. Comparing and analyzing the experimental results, the study shows that: (1) within a certain time, the axial and radial strain of the raw coal sample induced by CO2 adsorption both show a growing trend as the adsorption time increases and the strain of the raw coal sample for CO2 adsorption is obvious anisotropy; (2) at the same point in time, the greater the axial effective stress, the smaller the axial strain increasing rate of the loaded coal sample during CO2 adsorption process and the smaller the value of axial deformation; (3) during the adsorption process, the volume strain of raw coal sample decreases with the increasing of temperature, namely, the adsorption capacity of raw coal sample decreases with the increasing of temperature.

scholarly journals Deformation Mechanism of the Coal ahead of Fully Mechanized Caving Face under High-Intensity Mining Condition

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Can Zhao ◽  
Liang Chen ◽  
Bing Wu ◽  
Jingui Zhang ◽  
Dahe Yan ◽  
...  
Keyword(s):  
Axial Compression ◽  
High Intensity ◽  
Mechanical Model ◽  
Coal Sample ◽  
Axial Strain ◽  
Radial Strain ◽  
Good Reliability ◽  
Equivalent Mechanical Model ◽  
Coal Deformation ◽  
Triaxial Experiment

In order to study the coal deformation and failure mechanism in fully mechanized caving face under the high-intensity mining, based on the equivalent mechanical model of transversely isotropic cylindrical coal with fractures, the equivalent equations for axial, radial, and volume strains of coal sample loaded in linear elastic and plastic stages were derived in this paper. The equivalent mechanical model shows good reliability through the conventional triaxial experiment. Taking the N1206 workface in Yuwu coal mine of Luan group as the example, we have simulated the stress concentration factor of the coal body ahead of the working face with FLAC and divided three regions according to stress distribution in coal mining. Mathematical equations were derived to express the horizontal and vertical stress, which provide theoretical guidance of the stress paths in triaxial experiment about real mining stress environment simulation. Experimental results show that the volume strain’s value is about 0.4% in the coal mass deformation progress of axial compression increasing slowly area. In axial compression increasing rapidly area, the volume strain’s value varies from 0.41% to 0.27%, and the radical strain changes from compression deformation to expansion deformation gradually. The volume strain of coal sample increases sharply in axial compression releasing rapidly area; meanwhile, there are good linear relationships between Poisson’s ratio and axial strain and radial strain.

scholarly journals Influence of the Presence of Different Alkali Cations and the Amount of Fe(CN)6 Vacancies on CO2 Adsorption on Copper Hexacyanoferrates

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3371 ◽  
Author(s):  
Svensson ◽  
Grins ◽  
Eklöf ◽  
Eriksson ◽  
Wardecki ◽  
...  
Keyword(s):  
Thermogravimetric Analysis ◽  
Prussian Blue ◽  
Co2 Adsorption ◽  
X Ray Diffraction ◽  
Alkali Cations ◽  
Prussian Blue Analogue ◽  
X Ray ◽  
Infra Red ◽  
Adsorption Desorption ◽  
Adsorption Capability

The CO2 adsorption on various Prussian blue analogue hexacyanoferrates was evaluated by thermogravimetric analysis. Compositions of prepared phases were verified by energy-dispersive X-ray spectroscopy, infra-red spectroscopy and powder X-ray diffraction. The influence of different alkali cations in the cubic Fm3m structures was investigated for nominal compositions A2/3Cu[Fe(CN)6]2/3 with A = vacant, Li, Na, K, Rb, Cs. The Rb and Cs compounds show the highest CO2 adsorption per unit cell, 3.3 molecules of CO2 at 20 C and 1 bar, while in terms of mmol/g the Na compound exhibits the highest adsorption capability, 3.8 mmol/g at 20 C and 1 bar. The fastest adsorption/desorption is exhibited by the A-cation free compound and the Li compound. The influence of the amount of Fe(CN)6 vacancies were assessed by determining the CO2 adsorption capabilities of Cu[Fe(CN)6]1/2 (Fm3m symmetry, nominally 50% vacancies), KCu[Fe(CN)6]3/4 (Fm3m symmetry, nominally 25% vacancies), and CsCu[Fe(CN)6] (I-4m2 symmetry, nominally 0% vacancies). Higher adsorption was, as expected, shown on compounds with higher vacancy concentrations.

Mechanical Properties of Single-Walled Carbon Nanotubes under Large Axial Deformation

2010 ◽  
Vol 97-101 ◽  
pp. 3910-3915
Author(s):  
Kun Cai
Keyword(s):  
Carbon Nanotubes ◽  
Axial Strain ◽  
Single Walled Carbon Nanotubes ◽  
Mapping Method ◽  
Axial Deformation ◽  
Engineering Strain ◽  
Single Walled Carbon ◽  
Graphitic Sheet ◽  
Zigzag Pattern ◽  
Walled Carbon Nanotubes

The deformation of single-walled carbon nanotubes (SWCNTs) under large axial strain is studied by a geometrical mapping method. The interactions between atoms in carbon nanotubes (CNTs) are described by Tersoff-Brenner potential. Results show the strain energy depends on chirality but hardly on tubes’ radii. For graphitic sheet under large axial deformation, the elastic moduli decrease with the increase of engineering strain under tension. The modulus reaches the peak value as the axial engineering strain reaches -0.08 for armchair pattern and -0.15 for zigzag pattern under compression.

Modeling of the Adsorption/Desorption Characteristics and Properties of Anthocyanins from Extruded Red Cabbage Juice by Macroporous Adsorbent Resin

2019 ◽  
Vol 15 (1-2) ◽  
Author(s):  
Pingjing Zhang ◽  
Liping Wang ◽  
Sheng Fang
Keyword(s):  
Adsorption Process ◽  
Fixed Bed ◽  
Order Kinetic ◽  
Adsorption And Desorption ◽  
Red Cabbage ◽  
Macroporous Resins ◽  
Freeze Dried ◽  
Order Kinetic Model ◽  
Color Density ◽  
Adsorption Desorption

AbstractThe adsorption/desorption characteristics, modeling and properties of anthocyanins from extruded red cabbage juice by macroporous resins were investigated. The static adsorption and desorption capacities of red cabbage anthocyanins on five macroporous resins were measured and compared. The X-5 resin showed the best capacities and was selected for the adsorption kinetics, isotherms and elution studies. The pseudo-second-order kinetic model and Langmuir isotherm model were used to describe the adsorption process and mechanism. Dynamic adsorption and desorption tests were performed on a fixed-bed column, and the loading and eluent conditions were optimized. The purity of anthocyanins in freeze-dried purified powder by the resin adsorption process is 21.3 ± 0.9 wt % and shows better stability in the air than the unpurified one. Finally, the antioxidant activity and color properties including color density, color intensity, color tonality and degradation index of the purified powders were measured.

Prediction of Stress-Strain Response Using Rotational Multiple Yield Surface Framework in Malaysian Residual Soil

2020 ◽  
Vol 843 ◽  
pp. 132-137
Author(s):  
Asmidar Alias ◽  
Mohd Jamaludin Md Noor ◽  
Abdul Samad Abdul Rahman
Keyword(s):  
Shear Strength ◽  
Effective Stress ◽  
Volume Change ◽  
Yield Surface ◽  
Axial Strain ◽  
The Body ◽  
Residual Soil ◽  
Strain Response ◽  
Stress Strain ◽  
Soil Volume

Soil settlement is normally quantified using conventional soil volume change models which are solely based on the effective stress and the role of shear strength is ignored due to the difficulties to incorporate in the framework. The Rotational Multiple Yield Surface Framework (RMYSF) is a soil volume change model developed from the standpoint of the interaction between the effective stress and shear strength. RMYSF incorporates the development of mobilised shear strength within the body of the soil whenever the soil is subjected to anisotropic compression. Currently the framework has been applied to predict the soil anisotropic stress-strain behaviour at any effective stress. This paper present the enhancement of this volume change framework using normalisation of axial strain with the understanding that the failure axial strain is not unique, but increases as the effective stress increases. This technique has essentially produced a better accuracy in the prediction of the stress-strain response for Malaysian residual soils. A series of drained tri-axial tests under various effective stresses has been conducted using specimens of 50mm diameter and 100mm height and from the stress-strain curves the inherent mobilised shear strength envelopes at various axial strains have been determined. These mobilised shear strength envelopes were then applied for the prediction of the soil stress-strain response. An excellent agreement between the predicted and the actual stress-strain curves has been achieved.

scholarly journals Further Insight into the Depth-Dependent Microstructural Response of Cartilage to Compression Using a Channel Indentation Technique

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Ashvin Thambyah ◽  
Neil D. Broom
Keyword(s):  
Stress Relaxation ◽  
Axial Strain ◽  
Compressive Strain ◽  
Microstructural Analysis ◽  
Elastic Response ◽  
Axial Deformation ◽  
Aspect Ratios ◽  
The Matrix ◽  
Tissue System ◽  
Relaxation Responses

Stress relaxation and structural analysis were used to investigate the zonally differentiated microstructural response to compression of the integrated cartilage-on-bone tissue system. Fifteen cartilage-on-bone samples were divided into three equal groups and their stress relaxation responses obtained at three different levels of axial compressive strain defined as low (~20%), medium (~40%) and high (~60%). All tests were performed using a channel indenter which included a central relief space designed to capture the response of the matrix adjacent to the directly loaded regions. On completion of each stress relaxation test and while maintaining the imposed axial strain, the samples were formalin fixed, decalcified, and then sectioned for microstructural analysis. Chondron aspect ratios were used to determine the extent of relative strain at different zonal depths. The stress relaxation response of cartilage to all three defined levels of axial strain displayed an initial highly viscous response followed by a significant elastic response. Chondron aspect ratio measurements showed that at the lowest level of compression, axial deformation was confined to the superficial cartilage layer, while in the medium and high axial strain samples the deformation extended into the midzone. The cells in the deep zone remained undeformed for all compression levels.

scholarly journals Recovery of phosphate from aqueous solution by magnetically recycled modified polishing powder composites

2019 ◽  
Vol 80 (7) ◽  
pp. 1357-1366
Author(s):  
Jianming Liu ◽  
Runying Bai ◽  
Junfeng Hao ◽  
Bowen Song ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Ligand Exchange ◽  
Adsorption Process ◽  
High Adsorption ◽  
Order Model ◽  
Powder Composites ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Ph Level ◽  
Adsorption Desorption

Abstract This study investigated a magnetically recycled modified polishing powder (CMIO@PP) as an adsorbent of phosphate; the CMIO@PP was synthesized by combining the modified La/Ce-containing waste polishing powder with CaO2-modified Fe3O4 (CMIO). Results indicate that the CMIO@PP nanocomposite presents a crystal structure comprising La (OH)3, Ce (OH)3, and Fe3O4, and that CMIO is uniformly dispersed in the modified polishing powder. The CMIO@PP (1:3) is a suitable choice considering its magnetism and adsorption capacity. The magnetic adsorbent exhibits a high adsorption capacity of 53.72 mg/g, a short equilibrium time of 60 min, and superior selectivity for phosphate. Moreover, the adsorbent strongly depends on the pH during the adsorption process and maintains a large adsorption capacity when the pH level is between 2 and 6. The adsorption of phosphate by the CMIO@PP (1:3) accords with the Langmuir isotherm model, and the adsorption process follows the pseudo-second order model. Meanwhile, adsorption–desorption experiments show that the adsorbent could be recycled a few times and that a high removal efficiency of phosphate from civil wastewater was achieved. Finally, mechanisms show that the adsorption of phosphate by the CMIO@PP (1:3) is mainly caused by electrostatic attraction and ligand exchange.

scholarly journals Batch studies of phosphonate adsorption on granular ferric hydroxides

2020 ◽  
Vol 81 (1) ◽  
pp. 10-20 ◽  
Author(s):  
T. Reinhardt ◽  
M. Gómez Elordi ◽  
R. Minke ◽  
H. Schönberger ◽  
E. Rott
Keyword(s):  
Contact Time ◽  
Room Temperature ◽  
Adsorption Process ◽  
Ferric Hydroxide ◽  
Batch Experiments ◽  
Batch Studies ◽  
Influence Of Temperature ◽  
Ph Values ◽  
Adsorption Desorption ◽  
Granular Ferric Hydroxide

Abstract Phosphonates are widely used in various industries. It is desirable to remove them before discharging phosphonate-containing wastewater. This study describes a large number of batch experiments with adsorbents that are likely suitable for the removal of phosphonates. For this, adsorption isotherms for four different granular ferric hydroxide (GFH) adsorbents were determined at different pH values in order to identify the best performing material. Additionally, the influence of temperature was studied for this GFH. A maximum loading for nitrilotrimethylphosphonic acid (NTMP) was found to be ∼12 mg P/g with an initial concentration of 1 mg/L NTMP-P and a contact time of 7 days at room temperature. Then, the adsorption of six different phosphonates was investigated as a function of pH. It was shown that GFH could be used to remove all investigated phosphonates from water and, with an increasing pH, the adsorption capacity decreased for all six phosphonates. Finally, five adsorption–desorption cycles were carried out to check the suitability of the material for multiple re-use. Even after five cycles, the adsorption process still performed well.

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