ORCID Profile
0000-0001-6771-0224
Current Organisations
China University of Mining and Technology
,
University of Virginia Darden School of Business
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: IOP Publishing
Date: 10-2020
DOI: 10.1088/1755-1315/570/6/062017
Abstract: A new index named CT-derived carbonation index is proposed to evaluate CO 2 -induced cement degradation in CO 2 -rich corrosive environment. This index is obtained by conducting CT scanning of cement s les before and after exposure to CO 2 , calculating grayscale difference and applying an algorithm to correlate grayscale with CaCO 3 content. To demonstrate how to calculate the carbonation index, a CO 2 -cement interaction experiment along with X-ray computed micro-tomography characterization of a cement s le before and after exposure to CO 2 was carried out to investigate the degree of cement carbonation. CO 2 was dissolved in 1 wt% NaCl solution under a CO 2 partial pressure of 17 MPa and a temperature of 63 °C. The carbonate shell in the cement s le was segmented from the grayscale difference images and the average penetration depth of the carbonate shell was obtained. The carbonation index was then calculated as the ratio of the average penetration depth of the carbonate shell to the radius of the s le, ided by the reaction time. In this study, the carbonation index of the cement s le exposed to CO 2 for 14 days was 0.01 day −1 . Based on the results in this study and other studies, a carbonation index of 0.05 day −1 or above corresponds to heavy degradation of cement by CO 2 .
Publisher: Elsevier BV
Date: 07-2017
Publisher: Springer Science and Business Media LLC
Date: 06-04-2022
Publisher: Elsevier BV
Date: 03-2014
Publisher: Center for Open Science
Date: 02-09-2020
Abstract: Changing collective behaviour and supporting non-pharmaceutical interventions is an important component in mitigating virus transmission during a pandemic. In a large international collaboration (Study 1, N = 49,968 across 67 countries), we investigated self-reported factors that associated with people reported adopting public health behaviours (e.g., spatial distancing and stricter hygiene) and endorsed public policy interventions (e.g., closing bars and restaurants) during the early stage of the pandemic (April-May 2020). Respondents who reported identifying more strongly with their nation consistently reported greater engagement in public health behaviours and support for public health policies. Results were similar for representative and non-representative national s les. Study 2 (N = 42 countries) conceptually replicated the central finding using aggregate indices of national identity (obtained using the World Values Survey) and a measure of actual behaviour change during the pandemic (obtained from Google mobility reports). Higher levels of national identification prior to the pandemic predicted lower mobility during the early stage of the pandemic (r = -.40). We discuss the potential implications of links between national identity, leadership, and public health for managing COVID-19 and future pandemics.
Publisher: Elsevier BV
Date: 07-2020
Publisher: Springer Science and Business Media LLC
Date: 12-04-2022
DOI: 10.1007/S11356-022-20131-2
Abstract: Cemented tailings backfill (CTB) is widely adopted to ensure the safety of underground goafs and mitigate environmental risks. Fly ash (FA) and calcium formate (CF) are common industrial by-products that improve the mechanical performance of CTB. How the coupling of the two components affects the strength development is not yet well-understood. Neural network modelling was conducted to predict the strength development, including the static indicator of uniaxial compressive strength (UCS) and the dynamic indicator of ultrasonic pulse velocity (UPV). Sobol' sensitivity analysis was carried out to reveal the contributions of FA, CF and curing time to CTB strength. SEM microstructure investigation on CTB s les was implemented to reveal the mechanism of strength development and justify the predictions by neural network modelling and sensitivity analysis. Results show that the combination of FA content, CF content and curing time can be used to predict both UCS and UPV while providing adequate accuracy. The maximum of UCS of 6.1215 MPa is achieved at (FA content, CF content, curing time) = (13.78 w%, 3.76 w%, 28 days), and the maximum of UPV of 2.9887 km/s is arrived at (FA content, CF content, curing time) = (11.67 w%, 3.08 w%, 10 days). It is also implicated that prediction of UCS using UPV alone, although common in field application is not recommended. However, UPV measurement, in combination with the information of FA dosage, CF dosage and curing time, could be used to improve UCS prediction. The rank of variable significance for UCS is curing time > FA content > CF content, and for UPV is FA content > curing time > CF content variable interaction is strongest for FA with CF for UCS development, and for FA with curing time for UPV evolution. Influence of FA on CTB strength development is due to improved polymerisation and consumption of Ca(OH)
Publisher: Elsevier BV
Date: 2019
DOI: 10.2139/SSRN.3365798
Publisher: Elsevier BV
Date: 02-2022
Publisher: Center for Open Science
Date: 18-05-2022
Abstract: The COVID-19 pandemic has affected all domains of human life, including the economic and social fabric of societies. One of the central strategies for managing public health throughout the pandemic has been through persuasive messaging and collective behavior change. To help scholars better understand the social and moral psychology behind public health behavior, we present a dataset comprising of 51,404 in iduals from 69 countries. This dataset was collected for the International Collaboration on Social Moral Psychology of COVID-19 project (ICSMP COVID-19). This social science survey invited participants around the world to complete a series of in idual differences and public health attitudes about COVID-19 during an early phase of the COVID-19 pandemic (between April and June 2020). The survey included seven broad categories of questions: COVID-19 beliefs and compliance behaviours identity and social attitudes ideology health and well-being moral beliefs and motivation personality traits and demographic variables. We report both raw and cleaned data, along with all survey materials, data visualisations, and psychometric evaluations of key variables.
Publisher: Elsevier BV
Date: 10-2015
Publisher: Trans Tech Publications, Ltd.
Date: 10-2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.825.344
Abstract: Heap bio-leaching technology is extensively applied to recover metals from low-grade complex ores in the mining industry, particularly the copper sulfide ores. Understanding the effect of bio-leaching process on the pore structure of packed particle beds is important to enhance the percolation and leaching performances with respect to design and operation of heap leaching system. The porosity, pore size distribution and degree of pore connectivity are the three most important features correlated with fluid flow in heap leaching operation. In this study, a spiral X-ray CT scanner, combined with 3D imaging and analysis, was used to characterize the complex pore structure of the packed ore particle beds before and after bioleaching copper sulfide ores. The results indicate that the pore structure has temporal and spatial variations during bio-leaching process.
Publisher: Springer Science and Business Media LLC
Date: 08-2014
Publisher: Springer Science and Business Media LLC
Date: 27-05-2020
Publisher: Elsevier BV
Date: 04-2021
Publisher: Elsevier BV
Date: 06-2021
Publisher: Springer Science and Business Media LLC
Date: 09-2017
Publisher: SPE
Date: 16-10-2017
DOI: 10.2118/187874-MS
Abstract: Pore-level imaging and modelling were shown to be robust and useful techniques, at least if applied to conventional rocks such as sandstones. This type of modelling directly within the pore space of the imaged s les provides valuable insights into rock heterogeneity, estimates local single and multi-phase flow properties, and serves as a key tool for upscaling and parameterizing Darcian models. Yet, numerous problems are still to be solved related to rocks with complex and hierarchical structure, such as carbonates, shales and coals. These rocks possess pore sizes in a wide range of values which has to be imaged with different resolutions in order to capture all relevant pore scales. This is due to so-called s le size/imaging resolution trade-off. To develop a detailed 3D structure model, such rocks are imaged using different resolutions and even using different imaging techniques. The problem lies with combining all these multiscale images into a single 3D digital structure model. In this work the recently developed multiscale image fusion technique was tested on complex carbonate s les with hierarchical structure. For two s les we performed a detailed structural study on two different scales: 3D XCT scanning (2.7 µm resolution) and 2D SEM imaging (0.9 µm pixel size). These two scales were fused to represent carbonate rocks structure with the predefined resolution of 0.9 µm and volume of 15003 voxels combining structural features discernible on both XCT and SEM images. Fused 3D images were used as input data to a hybrid median axis/maximum inscribed ball pore-network technique with subsequent modelling of permeability. Resulting simulated values were compared with laboratory measurement on the cores with dimeter of 5 cm. For the S le 1 micropores visible on XCT scan were not connected, thus, preventing any flow simulations. After fusion with SEM image simulated permeability agreed favourably with the measurements. For the S le 2 micropore network was percolating, but simulated permeability was lower than the experimental one. Incorporating sub-resolution porosity in this s le by adding SEM finer porosity structure resulted in higher permeability value very close to the laboratory measurement. In this contribution we also discuss why simulated and measured permeability values do not agree perfectly, which is most likely due to the scale difference between the volumes of simulated and measurement domains. We also covered all major drawbacks of the multiscale image fusion techniques and discussed possible solutions. Current study clearly showed the potential of this novel approach to facilitate pore-level modelling of flow and transport in rocks with complex and hierarchical structure such as carbonates, shales and coals. We believe that after some improvements and rigorous testing multiscale fusion technique may become a core tool in imaging and pore-level modelling of flow properties for complex rocks with hierarchical structure.
Publisher: Springer Singapore
Date: 11-10-2018
Publisher: Hindawi Limited
Date: 11-11-2019
DOI: 10.1155/2019/5164010
Abstract: In order to explore the process of acid- and CO 2 -induced degradation of wellbore cement and the development of pre-existing leakage channels in wellbore cement under sulfate-rich geological CO 2 storage conditions, wellbore cement s les were immersed in SO 4 2- -bearing brine solution for 7 days, and the s les after reacting with the low and circumneutral pH solutions were scanned by a micro-CT scanner. HCl+Na 2 SO 4 solution was used to simulate the low-pH condition in deep formation waters and the possible existence of high sulfate ion content in deep formation waters. The acidification and carbonation results were compared, and the results given different pH values and different curing conditions were compared as well. The results show that the degradation of cement was related to the pH value of the reaction solution. There was a significant dissolution in the exterior of the cement s le after exposure to the low-pH solution, but the dissolution surrounding a penetrating borehole at the center of the s le (mimicking a leakage pathway within the wellbore cement in geological CO 2 storage environment) was limited. Comparison between acidification and carbonation results in this study shows formation of a thick carbonate layer due to cement carbonation, and this layer was not observed in the acidification result. As for different curing conditions of cement s les, no significant difference in cement alteration depth was observed for the acidification case. For the carbonation case, precipitations in the borehole occurred in the cement s le cured at ambient pressure, while the cement s le cured at high pressure did not produce any precipitation in the borehole. This study provides valuable information on how low pH-induced corrosion and HCO 3 - -induced cement carbonation contribute to structure evolution of wellbore cement in SO 4 2- -bearing brine under geological CO 2 storage environment.
Publisher: Elsevier BV
Date: 05-2021
Publisher: Elsevier BV
Date: 11-2020
Publisher: Elsevier BV
Date: 08-2013
Publisher: Springer Science and Business Media LLC
Date: 26-01-2022
DOI: 10.1038/S41467-021-27668-9
Abstract: Changing collective behaviour and supporting non-pharmaceutical interventions is an important component in mitigating virus transmission during a pandemic. In a large international collaboration (Study 1, N = 49,968 across 67 countries), we investigated self-reported factors associated with public health behaviours (e.g., spatial distancing and stricter hygiene) and endorsed public policy interventions (e.g., closing bars and restaurants) during the early stage of the COVID-19 pandemic (April-May 2020). Respondents who reported identifying more strongly with their nation consistently reported greater engagement in public health behaviours and support for public health policies. Results were similar for representative and non-representative national s les. Study 2 ( N = 42 countries) conceptually replicated the central finding using aggregate indices of national identity (obtained using the World Values Survey) and a measure of actual behaviour change during the pandemic (obtained from Google mobility reports). Higher levels of national identification prior to the pandemic predicted lower mobility during the early stage of the pandemic ( r = −0.40). We discuss the potential implications of links between national identity, leadership, and public health for managing COVID-19 and future pandemics.
Publisher: Wiley
Date: 02-11-2020
Publisher: Elsevier BV
Date: 2017
Publisher: Yandy Scientific Press
Date: 19-08-2019
Publisher: Elsevier BV
Date: 12-2020
Publisher: Springer Science and Business Media LLC
Date: 26-01-2014
Location: China
Location: Australia
Location: United States of America
Location: United States of America
Start Date: 2020
End Date: 2022
Funder: China Postdoctoral Science Foundation
View Funded ActivityStart Date: 2019
End Date: 2021
Funder: National Natural Science Foundation of China
View Funded Activity