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Nanoscale mechanical property variations concerning mineral composition and contact of marine shale

Geoscience Frontiers 2022年第4期13卷 165-180页

作者： Yong Li Jianqi Chen derek Elsworth Zhejun Pan Xiaotian Ma State Key Laboratory of Coal Resources and Safe Mining College of Geosciences and Surveying EngineeringChina University of Mining and TechnologyBeijing 100083China Department of Energy and Mineral Engineering GeosciencesEMS Energy Institute and the G3 CenterPennsylvania State UniversityUniversity ParkPA 16802USA Key Laboratory of Continental Shale Hydrocarbon Accumulation and Efficient Development Ministry of EducationNortheast Petroleum UniversityDaqingHeilongjiang 163318China

Mechanical properties of shales are key parameters influencing hydrocarbon production – impacting borehole stability, hydraulic fracture extension and microscale variations in in situ stress. We use Ordovician shale(Sichuan Basin, China) as a type-example to characterize variations in mineral particle properties at microscale including particle morphology, form of contact and spatial distribution via mineral liberation analysis(MLA) and scanning electron microscopy(SEM). Deformation-based constitutive models are then built using finite element methods to define the impact of various architectures of fracture and mineral distributions at nanometer scale on the deformation characteristics at *** compositions of siliceous, calcareous and clay mineral particles are shown to be the key factors influencing brittleness. Shales with similar mineral composition show a spectrum of equivalent medium mechanical properties due to differing particle morphology and mineral heterogeneity. The predominance of small particles and/or point-point contacts are conducive to brittle failure, in general, and especially so when quartz-rich. Fracture morphology, length and extent of filling all influence shale deformability. High aspect-ratio fractures concentrate stress at fracture tips and are conducive to extension, as when part-filled by carbonate minerals. As fracture spacing increases, stress transfer between adjacent fractures weakens, stress concentrations are amplified and fracture extension is favored. The higher the fractal dimension of the fracture and heterogeneity of the host the more pervasive the fractures. Moreover, when fractures extend, their potential for intersection and interconnection contributes to a reduction in strength and the promotion of brittle failure. Thus, these results provide important theoretical insights into the role of heterogeneity on the deformability and strength of shale reservoirs with practical implications for their stimulation an

关键词： Shale oil and gas Shale lithofacies Mineral composition Multiscale mechanical property Nanoscale mechanics Finite-element simulation

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Environmental drivers of seasonal shifts in abundance of wild pigs(Sus scrofa)in a tropical island environment

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Ecological Processes 2022年第1期11卷 772-786页

作者： derek R.Risch Shaya Honarvar Melissa R.Price Natural Resources and Environmental Department University of Hawaiʻi at Mānoa1910 East-West RoadHonoluluHI 96822USA Pacific Cooperative Studies Unit University of Hawaiʻi at Mānoa3190 Maile WayHonoluluHI 96822USA

Background:Non-native wild pigs(Sus scrofa)threaten sensitive flora and fauna,cost billions of dollars in economic damage,and pose a significant human–wildlife conflict *** growing interest in wild pig research,basic life history information is often lacking throughout their introduced range and particularly in tropical *** to other large terrestrial mammals,pigs possess the ability to shift their range based on local climatic conditions or resource availability,further complicating management *** objectives of this study were to(i)model the distribution and abundance of wild pigs across two seasons within a single calendar year;(ii)determine the most important environmental variables driving changes in pig distribution and abundance;and(iii)highlight key differences between seasonal models and their potential management *** study objectives were achieved using zero-inflated models constructed from abundance data obtained from extensive field surveys and remotely sensed environmental ***:Our models demonstrate a considerable change in distribution and abundance of wild pigs throughout a single calendar *** and vegetation height were among the most influential variables for pig distribution during the spring,and distance to adjacent forest and vegetation density were among the most significant for the ***,our seasonal models show that areas of high conservation value may be more vulnerable to threats from wild pigs at certain times throughout the year,which was not captured by more traditional modeling approaches using aggregated ***:Our results suggest that(i)wild pigs can considerably shift their range throughout the calendar year,even in tropical environments;(ii)pigs prefer dense forested areas in the presence of either hunting pressure or an abundance of frugivorous plants,but may shift to adjacent areas in the absence of either of these conditions;and(iii)seasonal m

关键词： Ecology Spatial Temporal Species distribution modeling Wild boar Sus scrofa Feral pigs

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Influences of spherical tree canopy on thermal radiation disturbance to exterior wall under the condition of no shade cast on the wall

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Building Simulation 2022年第7期15卷 1367-1383页

作者： Tailong Zhang Xiaoyue Zhao Yu Zhao derek Lukolongo Mwewa Chabi Feng Qi School of Landscape Architecture Zhejiang A&F UniversityLin'an 371300China

Research on the influence of thermal radiation of tree canopies to adjacent exterior walls has relevance to the selection of tree species and the spatial arrangement of trees for urban *** the last decade,there have been many studies on the influence of tree shadows on the thermal environment and energy consumption of ***,there is a lack of research on how trees affect the thermal radiation of adjacent buildings,when they do not cast direct shadows on the *** view of this,a combination of experiment and simulation was used to explore the influence of spherical canopy on the intensity changes of net long-wave thermal radiation(T_(RDL))and net short-wave thermal radiation(T_(RDS))absorbed by the adjacent *** measured and simulated results show that the tree canopy has a T_(RD)(the sum of T_(RDL) and T_(RDS))effect on the south wall of adjacent buildings in *** peak of T_(RD) from the tree to the adjacent wall was obtained by ENVI-met under 27 scenarios.A functional relationship was further given between the peak T_(RD) and the canopy diameter(D_(C)),the minimum distance between wall and tree canopy(D_(W-T)).Moreover,the influence of D_(C),D_(W-T) and leaf area density(LAD)on T_(RD) was discussed by ***,the Trd of canopy decays exponentially in the horizontal direction and linearly in the vertical direction of the *** above methods and results can guide the selection of tree species,green space design around buildings and the evaluation of the influence of trees on indoor cooling energy consumption in summer.

关键词： tree canopy thermal radiation disturbance exterior wall ENVI-met

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Frictional stability of Longmaxi shale gouges and its implication for deep seismic potential in the southeastern Sichuan Basin

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Deep Underground Science and Engineering 2022年第1期1卷 3-14页

作者： Fengshou Zhang Li Cui Mengke An derek Elsworth Changrong He Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghaiChina Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghaiChina Department of Energy and Mineral Engineering EMS Energy Institute and G3 CenterThe Pennsylvania State UniversityState CollegePennsylvaniaUSA Department of Geosciences The Pennsylvania State UniversityState CollegePennsylvaniaUSA State Key Laboratory of Earthquake Dynamics Institute of GeologyChina Earthquake AdministrationBeijingChina

Microearthquakes accompanying shale gas recovery highlight the importance of exploring the frictional and stability properties of shale *** to reveal the influencing factors on fault stability,this paper explores the impact of mineral compositions,effective stress and temperature on the frictional stability of Longmaxi shale gouges in deep reservoirs located in the Luzhou area,southeastern Sichuan *** shear experiments were conducted to define the frictional strength and stability of five shale *** specific experimental conditions were as follows:temperatures:90–270°C;a confining stress:95 MPa;and pore fluid pressures:25–55 *** results show that all five shale gouges generally display high frictional strength with friction coefficients ranging from 0.60 to 0.70 at the aforementioned experiment condition of pressures,and *** stability is significantly affected by temperature and mineral compositions,but is insensitive to variation in pore fluid *** instability is enhanced at higher temperatures(especially at>200°C)and with higher tectosilicate/carbonate *** results demonstrate that the combined effect of mineral composition and temperature is particularly important for induced seismicity during hydraulic fracturing in deep shale reservoirs.

关键词： deep shale reservoir hydraulic fracturing hydrothermal condition induced seismicity mineral composition shale fault stability

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Perforation optimization of layer-penetration fracturing for commingling gas production in coal measure strata

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Petroleum Science 2022年第4期19卷 1718-1734页

作者： Bing Hou Zhuang Cui Ji-Hui Ding Feng-Shou Zhang Li Zhuang derek Elsworth State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum-BejingBejing102249China MOE Key Laboratory of Petroleum Engineering in China University of Petroleum Beijing 102249China Department of Geophysics Stanford University397 Panama MallStanfordCA94305USA Department of Geotechnical Engineering Tongji UniversityShanghai200092China Korea Institute of Civil Engineering and Building Technology Goyang10223South Korea The Pennsylvania State University University ParkPA16802USA

Optimization of fracturing perforation is of great importance to the commingling gas production in coal measure *** this paper,a 3 D lattice algorithm hydraulic fracturing simulator was employed to study the effects of perforation position and length on hydraulic fracture propagation in coal measures of the Lin-Xing block,*** on field data,three lithologic combinations are simulated:1)a thick section of coal seam sandwiched by sandstones;2)a thin coal seam layer overlay by gas-bearing tight sandstone;3)two coal seams separated by a thin layer of *** simulation shows that perforation position and length in multi-layer reservoirs play a major role in hydraulic fracture *** maximum stimulated volume requires consideration of lithologic sequence,coal seam thickness,stress states,and rock *** improve the combined gas production in coal measure strata,it is possible to simultaneously stimulate multiple coal seams or adjacent gas-bearing *** these cases,perforation location and length also significantly impact fracture propagation,and therefore should be carefully *** simulation results using 3 D lattice algorithm are qualitatively consistent with laboratory physical simulation.3 D lattice models can be used to effectively simulate the fracture propagation through layers in coal measure *** numerical results provide guidance for perforation optimization in the hydraulic fracturing of coal measure strata.

关键词： Coal measure strata Combined production 3D lattice algorithm Perforation scheme optimization Fracture propagation

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Small moleculeπ-conjugated electron acceptor for highly enhanced photocatalytic nitrogen reduction of BiOBr

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Journal of Materials Science & Technology 2022年第14期109卷 276-281页

作者： derek Hao Tianyi Ma Baohua Jia Yunxia Wei Xiaojuan Bai Wei Wei Bing-Jie Ni Centre for Technology in Water and Wastewater(CTWW) School of Civil and Environmental EngineeringUniversity of Technology Sydney(UTS)SydneyNSW 2007Australia Centre for Translational Atomaterials Faculty of ScienceEngineering and TechnologySwinburne University of TechnologyHawthornVIC 3122Australia College of Chemistry and Chemical Engineering Lanzhou City UniversityLanzhou 730070China Beijing Engineering Research Center of Sustainable Urban Sewage System Construction and Risk Control Beijing University of Civil Engineering and ArchitectureBeijing 102612China

Artificial ammonia synthesis using solar energy is of great significance as it can help narrow the gap to the zero-net emission ***,the current photocatalytic activity is generally too low for mass ***,we report a novel bismuth bromide oxide(BiOBr)-Tetracyanoquinodimethane(TCNQ)photocatalyst prepared via a facile self-assembly *** to the well-match band structure of TCNQ and Bi OBr,the separation and transfer of photogenerated electron-hole pairs were significantly *** importantly,the abundant delocalizedπelectrons of TCNQ,and the electron-withdrawing property of TNCQ made electrons efficiently accumulated on the catalysts,which can strengthen the adsorption and cleavage of nitrogen *** a result,the photocatalytic activity increased *** highest ammonia yield of the optimized sample reached 2.617 mg/(h gcat),which was 5.6-fold as that of pristine BiOBr and higher than the reported BiOBr-based *** isotope labeled^(15)N_(2)was used to confirm that the ammonia is formed form the fixation of N_(2).Meanwhile,the sample also had good *** 4-time usage,the photocatalysts still had about 81.8%as the fresh *** results of this work provide a new way for optimizing the electronic structure of photocatalysts to achieve highly efficient photochemical N_(2) reduction.

关键词： BiOBr TCNQ Nitrogen reduction Electron accepter Photocatalysis。

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Determination of Effectiveness of Energy Management System in Buildings

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Energy Engineering 2023年第2期120卷 561-586页

作者： Vivash Karki Roseline Mostafa Bhaskaran Gopalakrishnan derek R.Johnson University of Rochester RochesterNY14627USA Industrial and Management Systems Engineering West Virginia UniversityMorgantownWV26505USA Mechanical and Aerospace Engineering West Virginia UniversityMorgantownWV26505USA

Building Energy Management Systems(BEMS)are computer-based systems that aid in managing,controlling,and monitoring the building technical services and energy consumption by equipment used in the *** effectiveness of BEMS is dependent upon numerous factors,among which the operational characteristics of the building and the BEMS control parameters also play an essential *** research develops a user-driven simulation tool where users can input the building parameters and BEMS controls to determine the effectiveness of their *** simulation tool gives the user the flexibility to understand the potential energy savings by employing specific BEMS control and help in making intelligent *** simulation is developed using Visual Basic Application(VBA)in Microsoft Excel,based on discrete-event Monte Carlo Simulation(MCS).The simulation works by initially calculating the energy required for space cooling and heating based on current building parameters input by the user in the ***,during the second simulation,the user selects all the BEMS controls and improved building envelope to determine the energy required for space cooling and heating during that *** model compares the energy consumption from the first simulation and the second *** the simulation model will provide the rating of the effectiveness of BEMS on a continuous scale of 1 to 5(1 being poor effectiveness and 5 being excellent effectiveness of BEMS).This work is intended to facilitate building owner/energy managers to analyze the building energy performance concerning the efficacy of their energy management system.

关键词： Buildings energy management system demand controlled ventilation supply air temperature reset temperature setback control monte carlo simulation

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Broadening the application of forensic science in an era of standardization

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Forensic Sciences Research 2022年第3期7卷 331-333页

作者： derek Congram Oran Finegan International Committee of the Red Cross

In late July 2021,the Ministry of Veteran Affairs of the People’s Republic of China released a statement about the repatriation of the remains of Chinese sol-diers from the Korean War,which had been recovered by the Republic of Korea:“Following humanitarian principles and in the spirit of friendly consultation and practical cooperation,China and South Korea…will further deepen the exchanges and cooperation between the two coun-tries in the joint search,excavation,and identi-fication of the remains of the Chinese People’s Volunteers in South Korea”(translation to English by Yizhang Fan)[1].

关键词： statement Korea cooperation

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Dynamic energy system modeling using hybrid physics-based and machinelearning encoder–decoder models

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能源与人工智能(英文) 2022年第3期9卷 128-138页

作者： derek Machalek Jake Tuttle Klas Andersson Kody M.Powell Department of Chemical Engineering University of UtahSalt Lake CityUTUnited States of America Taber International LLCUnited States of America Department of Space Earthand EnvironmentUniversity of ChalmersGothenburgSweden Department of Mechanical Engineering University of UtahSalt Lake CityUTUnited States of America

Three model configurations are presented for multi-step time series predictions of the heat absorbed by thewater and steam in a thermal power plant. The models predict over horizons of 2, 4, and 6 steps into thefuture, where each step is a 5-minute increment. The evaluated models are a pure machine learning model, anovel hybrid machine learning and physics-based model, and the hybrid model with an incomplete dataset. Thehybrid model deconstructs the machine learning into individual boiler heat absorption units: economizer, waterwall, superheater, and reheater. Each configuration uses a gated recurrent unit (GRU) or a GRU-based encoder–decoder as the deep learning architecture. Mean squared error is used to evaluate the models compared totarget values. The encoder–decoder architecture is over 11% more accurate than the GRU only models. Thehybrid model with the incomplete dataset highlights the importance of the manipulated variables to the *** hybrid model, compared to the pure machine learning model, is over 10% more accurate on averageover 20 iterations of each model. Automatic differentiation is applied to the hybrid model to perform a localsensitivity analysis to identify the most impactful of the 72 manipulated variables on the heat absorbed in theboiler. The models and sensitivity analyses are used in a discussion about optimizing the thermal power plant.

关键词： Hybrid model Encoder-decoder Time series Automatic differentiation Thermal power plant

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Use of machine learning algorithms to assess the state of rockburst hazard in underground coal mine openings

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第3期14卷 703-713页

作者： Lukasz Wojtecki Sebastian Iwaszenko derek B.Apel Mirosawa Bukowska Janusz Makówka Central Mining Institute Katowice40-166Poland School of Mining and Petroleum Engineering University of AlbertaEdmontonT6G 2R3Canada

The risk of rockbursts is one of the main threats in hard coal mines. Compared to other underground mines, the number of factors contributing to the rockburst at underground coal mines is much *** such as the coal seam tendency to rockbursts, the thickness of the coal seam, and the stress level in the seam have to be considered, but also the entire coal seam-surrounding rock system has to be evaluated when trying to predict the rockbursts. However, in hard coal mines, there are stroke or stress-stroke rockbursts in which the fracture of a thick layer of sandstone plays an essential role in predicting rockbursts. The occurrence of rockbursts in coal mines is complex, and their prediction is even more difficult than in other mines. In recent years, the interest in machine learning algorithms for solving complex nonlinear problems has increased, which also applies to geosciences. This study attempts to use machine learning algorithms, i.e. neural network, decision tree, random forest, gradient boosting, and extreme gradient boosting(XGB), to assess the rockburst hazard of an active hard coal mine in the Upper Silesian Coal Basin. The rock mass bursting tendency index WTGthat describes the tendency of the seam-surrounding rock system to rockbursts and the anomaly of the vertical stress component were applied for this purpose. Especially, the decision tree and neural network models were proved to be effective in correctly distinguishing rockbursts from tremors, after which the excavation was not damaged. On average, these models correctly classified about 80% of the rockbursts in the testing datasets.

关键词： Hard coal mining Rockburst hazard Machine learning algorithms

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