Changes in pore structure and permeability of anthracite coal before and after high-voltage electrical pulses treatment

The low gas permeability of coal formations with limited coal pores and fractures leads to difficulty in coalbed methane exploration. High-voltage electrical pulse has a potential application in enhanced coalbed methane recovery. In this study, we discuss the microscopic characteristics of anthracite coals treated by high-voltage electrical pulse. We find that C, O, and other coal elements constituting oxygenic groups, which mainly account for gas adsorption, decreased slightly after high-voltage electrical pulse treatment, indicating that elemental variation may have little influence on gas adsorption. The scanning electron microscopy and low-pressure nitrogen gas adsorption (LP-N2GA) results show that the cumulative micropore volumes of high-voltage electrical pulse-treated coals were much larger than those of original coals. The mercury intrusion porosimetry results show that the cumulative macropore volumes, which act as gas migration channels in coal increased. Additionally, high-voltage electrical pulse-treated coals were found to have smaller entrapment areas, indicating that gas migration was enhanced.

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Experimental study on the effect of high-voltage electrical pulses on the nanoscale pore structure of coal

Fuel ◽

10.1016/j.fuel.2021.121621 ◽

2021 ◽

Vol 306 ◽

pp. 121621

Author(s):

Zhen Ni ◽

Baiquan Lin ◽

Xiangliang Zhang ◽

Xuan Cao ◽

Lubin Zhong ◽

...

Keyword(s):

Experimental Study ◽

Pore Structure ◽

High Voltage ◽

Electrical Pulses ◽

Nanoscale Pore

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Real-Time High-Level Acute Pain Detection Using a Smartphone and a Wrist-Worn Electrodermal Activity Sensor

Sensors ◽

10.3390/s21123956 ◽

2021 ◽

Vol 21 (12) ◽

pp. 3956

Author(s):

Youngsun Kong ◽

Hugo F. Posada-Quintero ◽

Ki H. Chon

Keyword(s):

Real Time ◽

Electrodermal Activity ◽

Smartphone Application ◽

Real Time Processing ◽

Pain Stimulation ◽

Significant Difference ◽

Before And After ◽

Electrical Pulses ◽

Pain Detection ◽

High Level

The subjectiveness of pain can lead to inaccurate prescribing of pain medication, which can exacerbate drug addiction and overdose. Given that pain is often experienced in patients’ homes, there is an urgent need for ambulatory devices that can quantify pain in real-time. We implemented three time- and frequency-domain electrodermal activity (EDA) indices in our smartphone application that collects EDA signals using a wrist-worn device. We then evaluated our computational algorithms using thermal grill data from ten subjects. The thermal grill delivered a level of pain that was calibrated for each subject to be 8 out of 10 on a visual analog scale (VAS). Furthermore, we simulated the real-time processing of the smartphone application using a dataset pre-collected from another group of fifteen subjects who underwent pain stimulation using electrical pulses, which elicited a VAS pain score level 7 out of 10. All EDA features showed significant difference between painless and pain segments, termed for the 5-s segments before and after each pain stimulus. Random forest showed the highest accuracy in detecting pain, 81.5%, with 78.9% sensitivity and 84.2% specificity with leave-one-subject-out cross-validation approach. Our results show the potential of a smartphone application to provide near real-time objective pain detection.

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Carbon Capture Performance of Amino-Modified MIL-101 at Room Temperature

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.395-396.637 ◽

2013 ◽

Vol 395-396 ◽

pp. 637-640

Author(s):

Yi Yang ◽

Zheng Ping Wang ◽

Ling Meng ◽

Lian Jun Wang

Keyword(s):

Carbon Dioxide ◽

Specific Surface ◽

Pore Structure ◽

Carbon Capture ◽

Room Temperature ◽

Ambient Pressure ◽

Metal Organic Framework ◽

Adsorption Properties ◽

Carbon Dioxide Adsorption ◽

Before And After

MIL-101, a metal-organic framework material, was synthesized by the high-temperature hydrothermal method. Triethylenetetramine (TETA) modification enabled the effective grafting of an amino group onto the surface of the materials and their pore structure. The crystal structure, micromorphology, specific surface area, and pore structure of the samples before and after modification were analyzed with an X-ray diffractometer, scanning electron microscope, specific surface and aperture tester, and infrared spectrometer. The carbon dioxide adsorption properties of the samples were determined by a thermal analyzer before and after TETA modification. Results show that moderate amino modification can effectively improve the microporous structure of MIL-101 and its carbon dioxide adsorption properties. After modification, the capacity of MIL-101 to adsorb carbon dioxide decreased only by 0.61 wt%, and a high adsorption capacity of 9.45 wt% was maintained after six cycles of adsorption testing at room temperature and ambient pressure.

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Changes in Pore Structure of Coal Caused by CS2 Treatment and Its Methane Adsorption Response

Geofluids ◽

10.1155/2018/7578967 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11 ◽

Cited By ~ 4

Author(s):

Run Chen ◽

Yong Qin ◽

Pengfei Zhang ◽

Youyang Wang

Keyword(s):

Pore Structure ◽

Adsorption Capacity ◽

Gas Adsorption ◽

Recovery Process ◽

Micropore Volume ◽

Methane Adsorption ◽

Coal Bed ◽

Methane Recovery ◽

Before And After ◽

Key Issues

The pore structure and gas adsorption are two key issues that affect the coal bed methane recovery process significantly. To change pore structure and gas adsorption, 5 coals with different ranks were treated by CS2 for 3 h using a Soxhlet extractor under ultrasonic oscillation conditions; the evolutions of pore structure and methane adsorption were examined using a high-pressure mercury intrusion porosimeter (MIP) with an AutoPore IV 9310 series mercury instrument. The results show that the cumulative pore volume and specific surface area (SSA) were increased after CS2 treatment, and the incremental micropore volume and SSA were increased and decreased before and after Ro,max=1.3%, respectively; the incremental big pore (greater than 10 nm in diameter) volumes were increased and SSA was decreased for all coals, and pore connectivity was improved. Methane adsorption capacity on coal before and after Ro,max=1.3% also was increased and decreased, respectively. There is a positive correlation between the changes in the micropore SSA and the Langmuir volume. It confirms that the changes in pore structure and methane adsorption capacity due to CS2 treatment are controlled by the rank, and the change in methane adsorption is impacted by the change of micropore SSA and suggests that the changes in pore structure are better for gas migration; the alteration in methane adsorption capacity is worse and better for methane recovery before and after Ro,max=1.3%. A conceptual mechanism of pore structure is proposed to explain methane adsorption capacity on CS2 treated coal around the Ro,max=1.3%.

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Pore Structure Damages in Cement-Based Materials by Mercury Intrusion: A Non-Destructive Assessment by X-Ray Computed Tomography

Materials ◽

10.3390/ma12142220 ◽

2019 ◽

Vol 12 (14) ◽

pp. 2220 ◽

Cited By ~ 8

Author(s):

Xiaohu Wang ◽

Yu Peng ◽

Jiyang Wang ◽

Qiang Zeng

Keyword(s):

Computed Tomography ◽

Pore Structure ◽

High Mass ◽

X Ray ◽

Quantitative Evidence ◽

Mercury Intrusion ◽

Pore Size Distributions ◽

Cement Based Materials ◽

Before And After ◽

X Ray Computed

Mercury intrusion porosimetry (MIP) is questioned for possibly damaging the micro structure of cement-based materials (CBMs), but this theme still has a lack of quantitative evidence. By using X-ray computed tomography (XCT), this study reported an experimental investigation on probing the pore structure damages in paste and mortar samples after a standard MIP test. XCT scans were performed on the samples before and after mercury intrusion. Because of its very high mass attenuation coefficient, mercury can greatly enhance the contrast of XCT images, paving a path to probe the same pores with and without mercury fillings. The paste and mortar showed the different MIP pore size distributions but similar intrusion processes. A grey value inverse for the pores and material skeletons before and after MIP was found. With the features of excellent data reliability and robustness verified by a threshold analysis, the XCT results characterized the surface structure of voids, and diagnosed the pore structure damages in terms of pore volume and size of the paste and mortar samples. The findings of this study deepen the understandings in pore structure damages in CBMs by mercury intrusion, and provide methodological insights in the microstructure characterization of CBMs by XCT.

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Novel Nanosized Patterning Techniques Using An Electropulsed Scanning Probe Microscope

MRS Proceedings ◽

10.1557/proc-728-s8.26 ◽

2002 ◽

Vol 728 ◽

Author(s):

L. V. Melo ◽

P. Brogueira

Keyword(s):

Surface Region ◽

Pulse Frequency ◽

Electrical Pulse ◽

Scanning Probe ◽

Before And After ◽

Electrical Pulses ◽

Probe Microscope ◽

Good Agreement ◽

Si Wafer ◽

40 Hz

AbstractScanning Probe Microscopes (SPM) have been used to change surfaces at nanometer scales. We report the deposition of user defined patterns in a controlled manner using an electropulsed SPM. The patterns were fabricated by applying -12 V electrical pulses in the 10 to 40 Hz range between a commercial CoCr conductive tip and a crystalline n-doped Si wafer. The tip damage during deposition is negligible as measurements on the same surface region before and after deposition show no detectable differences. Immediately after deposition the same tip is used for measuring the fabricated patterns. Applying one isolated electrical pulse results in a pixel with a typical size of the order of 30 nm. By combining the scanning ability of the SPM with the atmospheric deposition induced by electrical pulses on the tip, patterns can be fabricated. For example, by applying electrical pulses during a 25 nm x 800 nm tip scan in AFM tapping mode, at 40 Hz, lines with 65 nm width by 828 nm length were obtained (in good agreement with the expected dimensions of 55 nm x 830 nm derived from the pixel size and the scan range). The height of the deposited patterns is of the order of 2 to 3 nm, and was found to increase with the density of scan lines. The RMS roughness of the deposited material is shown to be strongly dependent on the electrical pulse frequency. The smoother pattern surface results from the 40 Hz pulse frequency. No deposition was observed at higher frequencies.

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Electrostrictive energy conversion property of cellular electrets after corona discharge

International Journal of Modern Physics B ◽

10.1142/s0217979218500698 ◽

2018 ◽

Vol 32 (07) ◽

pp. 1850069 ◽

Cited By ~ 1

Author(s):

J. W. Zhang ◽

F. K. Gao ◽

H. C. Sun ◽

C. Putson ◽

R. T. Liu

Keyword(s):

Energy Conversion ◽

Corona Discharge ◽

High Voltage ◽

Before And After ◽

Electric Dipoles ◽

Corona Poling ◽

The Impact ◽

Cellular Polymer ◽

Electrostrictive Effect

In this paper, the authors present the electrostrictive energy conversion ability of cellular electrets after the high-voltage corona polarization. Moreover, the electrostrictive effect of such foamed polymer before and after corona polarization has also been compared and discussed. The enhancement of electrostrictive effect of cellular electrets after corona polarization was observed. In particular, the impact on the electrostrictive effect of the macroscopic electric dipoles inside of cellular polymer which are generated by high-voltage corona poling procedure has been investigated. The present research has promoted the development of the application of electret in the field of energy conversion, actuator, transducers, etc.

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Design of an Irreversible Electroporation System for Clinical Use

Technology in Cancer Research & Treatment ◽

10.1177/153303460700600408 ◽

2007 ◽

Vol 6 (4) ◽

pp. 313-320 ◽

Cited By ~ 70

Author(s):

Claudio Bertacchini ◽

Pier Mauro Margotti ◽

Enrico Bergamini ◽

Andrea Lodi ◽

Mattia Ronchetti ◽

...

Keyword(s):

High Voltage ◽

Traditional Approach ◽

Irreversible Electroporation ◽

Target Volume ◽

High Energy ◽

Target Tissue ◽

Clinical Use ◽

Safety Issues ◽

Electrical Pulses ◽

Effective Delivery

Irreversible electroporation is an ablation modality in which microseconds, high-voltage electrical pulses are applied to induce cell necrosis in a target tissue. To perform irreversible electroporation it is necessary to use a medical device specifically designed for this use. The design of an irreversible electroporation system is a complex task in which the effective delivery of high energy pulses and the safety of the patient and operator are equally important. Pulses of up to 3000 V of amplitude and 50 A of current need to be generated to irreversibly electroporate a target volume of approximately 50 to 70 cm3 with as many as six separate electrodes; therefore, a traditional approach based on high voltage amplifiers becomes hard to implement. In this paper, we present the process that led to the first irreversible electroporator capable of such performances approved for clinical use. The main design choices and its architecture are outlined. Safety issues are also explained along with the solutions adopted.

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