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Articles 44941 - 44970 of 294457

Full-Text Articles in Physical Sciences and Mathematics

Wavefield Separation Of P- And S-Waves Based On Modified Pseudo-Helmholtz Decomposition Operator In Transverse Isotropic Media, Liu Zhaoshun, Du Qizhen, Lyu Wenhao, Zhou Shihao, Fu Liyun Mar 2023

Wavefield Separation Of P- And S-Waves Based On Modified Pseudo-Helmholtz Decomposition Operator In Transverse Isotropic Media, Liu Zhaoshun, Du Qizhen, Lyu Wenhao, Zhou Shihao, Fu Liyun

Coal Geology & Exploration

The separation of P- and S-wave fields is a significant step in elastic reverse-time migration (ERTM), which can effectively eliminate the waveform crosstalk and image artifacts, thus improving the precision of imaging. In anisotropic media, nonstationary spatial filters or low-rank approximation methods are commonly used to separate the wavefields. However, the application of multiple Fourier transforms results in the high computation costs of the above wavefield separation methods. Based on the idea of constructing the isotropic decoupling equations of P- and S- waves with the Helmholtz operator, a modified pseudo-Helmholtz decomposition operator was proposed to eliminate the amplitude distortion. Then, …

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Forward Modeling Of Radio-Magnetotelluric Method Based On Julia Acceleration And Study On Effect Of Displacement Current, Mei Zhuxu, Yuan Yuan, Zhou Feng, Zhou Cong, Zhang Lincheng Mar 2023

Forward Modeling Of Radio-Magnetotelluric Method Based On Julia Acceleration And Study On Effect Of Displacement Current, Mei Zhuxu, Yuan Yuan, Zhou Feng, Zhou Cong, Zhang Lincheng

Coal Geology & Exploration

Radio-magnetotelluric method (RMT) is one of the important tools for shallow surface electromagnetic exploration. Since the exploration frequency band is 10‒300 kHz, the propagation of electromagnetic fields is greatly affected by the dielectric permittivity of the earth. The electromagnetic response calculated with traditional quasi-static conditions severely restricts the accuracy of RMT forward modeling and further affects the resolution of the inversion imaging. In response to this problem, a numerical simulation method of full-current RMT electromagnetic response based on Julia parallel acceleration was proposed. Then, the calculation of each frequency point was sent through the distributed computing in Julia to different …

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One Surface Borehole With Multi-Usage Gas Drainage Key Technology For Abandoned Well And Its Application, Fu Junhui Mar 2023

One Surface Borehole With Multi-Usage Gas Drainage Key Technology For Abandoned Well And Its Application, Fu Junhui

Coal Geology & Exploration

Gas drainage from mining area could be realized through the reconstruction and reuse of abandoned surface gas wells in the coal mine area , which has multiple economic and environmental benefits such as ensuring the safe production of mining, the effective utilization of gas resources, and reducing the pressure of gas escape on the environment. In view of this purpose, the idea of “one surface borehole with multi-usage” gas drainage technology for abandoned wells was proposed based on the characteristics of the surface borehole and the abandoned wells in the mining area. By analyzing the conditions of the mining technology, …

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New Understanding Of Coal Seam Distribution Law: Coal Accumulation Model Controlled By Paleoclimate Evolution, Hou Haihai, Chen Hongzhen, Shao Longyi, Pan Zizi Mar 2023

New Understanding Of Coal Seam Distribution Law: Coal Accumulation Model Controlled By Paleoclimate Evolution, Hou Haihai, Chen Hongzhen, Shao Longyi, Pan Zizi

Coal Geology & Exploration

It is very important for coal and coal-measure gas exploration to correctly understand the distribution law of coal seam and its main control factors in different coal accumulation models. Based on the review of the theories and models of paleogeographic coal control, coal accumulation in sequence stratigraphy, allochthonous coal accumulation and multiple coal accumulation theoretical system, a new coal accumulation model under the control of climatic revolution was proposed through the analyses of the Jurassic coal-bearing strata in the southern margin of Junggar Basin. The paleotemperature and paleohumidity during Badaowan Formation(coal accumulation period), Sangonghe Formation, Xishanyao Formation (coal accumulation period) …

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A New Model Of Surface And Underground Integrated Three-Dimensional Prevention And Control Of Rock Burst In Binchang Mining Area, Wu Xueming, Ma Xiaohui, Lyu Dazhao, Zheng Kaige, Wang Dongjie Mar 2023

A New Model Of Surface And Underground Integrated Three-Dimensional Prevention And Control Of Rock Burst In Binchang Mining Area, Wu Xueming, Ma Xiaohui, Lyu Dazhao, Zheng Kaige, Wang Dongjie

Coal Geology & Exploration

With the continuous increase of coal mining intensity, the mine gradually moves to the deep, bringing about increasingly serious rock burst hazard. The deep rock burst mines often have one or more layers of hard and thick rock strata. These hard roofs are thick and strong integrity. When they suddenly rupture, they can release a large amount of elastic energies, which can easily to cause rock burst accidents and seriously restrict the safety of mine production. Herein, appropriate treatment measures were put forward for the special situation of deep burial depth of coal seam and general presence of many kinds …

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Co2-Ecbm Simulation Study Considering Klinkenberg Factor State, Sa Zhanyou, Wu Jingbo, Yang Yongliang, Zhang Xin, Lu Shouqing, Liu Jie, Wang Hao Mar 2023

Co2-Ecbm Simulation Study Considering Klinkenberg Factor State, Sa Zhanyou, Wu Jingbo, Yang Yongliang, Zhang Xin, Lu Shouqing, Liu Jie, Wang Hao

Coal Geology & Exploration

In order to explore the role of Klinkenberg effect and Klinkenberg factor in different states in the process of CO2-Enhanced Coal Bed Methane (CO2-ECBM), the effects of Klinkenberg factor of zero, fixed Klinkenberg factor and dynamic Klinkenberg factor on CO2-ECBM were simulated and analyzed by COMSOL finite element software. The dynamic changes of CH4 and CO2 pressure with this factor were studied, and the CH4 gas production was compared with the engineering practice. The results show that the effective permeability of CH4 and CO2 increases slowly at first, then …

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Study On The Time Law Of Water-Rock Interaction In Coal Mine Groundwater Reservoir, Zhang Kai, Liu Shuyu, Cao Zhiguo, Gao Ju, Chen Xiangyu, Yan Jiayu Mar 2023

Study On The Time Law Of Water-Rock Interaction In Coal Mine Groundwater Reservoir, Zhang Kai, Liu Shuyu, Cao Zhiguo, Gao Ju, Chen Xiangyu, Yan Jiayu

Coal Geology & Exploration

The retention time of mine water in the coal mine underground reservoir will affect the ion concentration of effluent, but the time law of water-rock interaction during operation of the reservoir is still unclear. In order to reveal the occurrence type and intensity of water-rock interaction in different operation stages of coal mine underground reservoir, two groups of static simulation tests of water-rock interaction were designed based on the test and analysis on-site samples, namely the fine sandstone-mine water (S-K) and mudstone-mine water (N-K). The types of water-rock interaction were analyzed from two aspects: the change of rock composition and …

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Deformation Prediction Of Open-Pit Mine Slope Based On Abc-Grnn Combined Model, Ning Yongxiang, Cui Ximin, Cui Jianguo Mar 2023

Deformation Prediction Of Open-Pit Mine Slope Based On Abc-Grnn Combined Model, Ning Yongxiang, Cui Ximin, Cui Jianguo

Coal Geology & Exploration

Accurate prediction of slope deformation in open-pit mine is an important guarantee for effective disaster early warning of slope. The traditional slope deformation prediction method is unable to characterize and comprehensively analyze the effect of various factors on slope deformation. In view of this, the combined prediction model (ABC-GRNN) of an artificial bee colony algorithm (ABC) and the optimized generalized regression neural network (GRNN) was proposed for slope deformation in open-pit mine. In this prediction model, the following 5 factors affecting the slope deformation of open-pit mine are considered comprehensively: mining disturbance, rainfall, rainfall duration, temperature and humidity. Herein, the …

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Influence Of Coal Mining Disturbance On Soil Physiochemical Properties And The Response Mechanism Of Microbial Community, Song Ziheng, Liu Gang, Sun Liping, Wang Fei, Guo Junting Mar 2023

Influence Of Coal Mining Disturbance On Soil Physiochemical Properties And The Response Mechanism Of Microbial Community, Song Ziheng, Liu Gang, Sun Liping, Wang Fei, Guo Junting

Coal Geology & Exploration

The ecological problems caused by coal mining in Yellow River Basin are becoming more serious. In order to explore the influence characteristics of coal mining disturbance on soil factors and microbial community in Yellow River Basin, and to clarify the differences in soil microbial communities between the marginal coal mining subsidence area and the unmined area, equidistant sampling was performed from the marginal subsidence area, the start point (HD), to the unmined area in the study area of Shangwan Mine in Inner Mongolia. Specifically, sampling points at 150 (D1), 300 (D2), 450 (D3), 600 (D4) and 750 m (D5) from …

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Feasibility Study Of Nature Source In-Seam Exploration, Hu Ze’An, Cao Lingkai, Liu Qinjie, Ji Guangzhong, Xi Chaoqiang, Wu Rongxin Mar 2023

Feasibility Study Of Nature Source In-Seam Exploration, Hu Ze’An, Cao Lingkai, Liu Qinjie, Ji Guangzhong, Xi Chaoqiang, Wu Rongxin

Coal Geology & Exploration

The conventional explosive seismic sources are very tightly controlled in high-gas mine, and a novel non-explosive channel wave method is urgently needed as an alternative. Therefore through the theoretical analysis and numerical simulation experiments, we demostrated that the coal seam satisfied the geophysical conditions to develop the nature source in-seam wave. The time-domain numerical simulation experiment of the passive source channel wave was successfully realized by constructing the nature source in-seam wave model with three stochastic terms, including the stochastic spatial position, stochastic initial excitation time and stochastic amplitude of seismic source. We performed frequency dispersion spectrum calculation on the …

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Inversion Of Self-Potential Data Based On Improved Sparrow Search Algorithm, Lang Jianxiang, Tang Hongzhi, Ai Hanbing Mar 2023

Inversion Of Self-Potential Data Based On Improved Sparrow Search Algorithm, Lang Jianxiang, Tang Hongzhi, Ai Hanbing

Coal Geology & Exploration

Self-potential (SP) method is a natural source geophysical prospecting technology with low cost and simple operation for field observation. Generally, the inversion of SP data has the characteristics of ill-posedness and non-linearity. The conventional inversion algorithms are classified into the types of local optimization and global search. However, it is hard for the gradient-based local optimization algorithm to obtain the global optimal solution, and the inversion results are dependent on the construction of initial model. The traditional global search algorithm has the disadvantages of low convergence rate, insufficient ability of escaping local minima and instability. Thus, a new global optimization …

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Development Of Storage Equipment Of Continuous Cable Pipe For Borehole Rescue, Gao Ke, Niu Xin, Zhao Yan, Qin Xiaolin, Lyu Xiaoshu, Xie Xiaobo Mar 2023

Development Of Storage Equipment Of Continuous Cable Pipe For Borehole Rescue, Gao Ke, Niu Xin, Zhao Yan, Qin Xiaolin, Lyu Xiaoshu, Xie Xiaobo

Coal Geology & Exploration

The double-bit bionic self-balancing continuous drilling technology has the advantages including requiring no drilling rig, high drilling speed and slight disturbance to the borehole wall. It is one of the key potential technologies for constructing the security and rescue passages against mine disasters. In this technology, as there are passages for power supply, signal, chip removal and other aspects that are built in the continuous cable pipe, it is required that there shall be no such interference, extrusion or arrangement of dynamic/static conductive electric conduction link as in using the existing drum hoist to store continuous pipes during storage. Therefore, …

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A Fault Diagnosis Method Of Rescue Lifting Vehicle Based On Spectral Clustering, Li Lijing, Chang Dashuai, Li Lei, Chai Junfei Mar 2023

A Fault Diagnosis Method Of Rescue Lifting Vehicle Based On Spectral Clustering, Li Lijing, Chang Dashuai, Li Lei, Chai Junfei

Coal Geology & Exploration

In allusion to the characteristics of complex structure of rescue lifting vehicle, the poor independence of working condition and fault data, and the difficulty in fault diagnosis, we proposed a fault diagnosis algorithm of rescue lifting vehicle with the semi-supervised support vector machine in this paper. In the algorithm, the information on hidden features of the original fault data was mined with the idea of spectral clustering, to effectively distinguish the independent structural features of the fault information in the component system with different degrees of coupling. Firstly, a fault map was established based on the original input data. Then, …

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Transport Effects In Non-Hermitian Nonreciprocal Systems: General Approach, Hamed Ghaemi-Dizicheh Mar 2023

Transport Effects In Non-Hermitian Nonreciprocal Systems: General Approach, Hamed Ghaemi-Dizicheh

Physics & Astronomy Faculty Publications

In this paper, we present a unifying analytical framework for identifying conditions for transport effects such as reflectionless and transparent transport, lasing, and coherent perfect absorption in non-Hermitian nonreciprocal systems using a generalized transfer matrix method. This provides a universal approach to studying the transport of tight-binding platforms, including higher-dimensional models and those with an internal degree of freedom going beyond the previously studied case of one-dimensional chains with nearest-neighbor couplings. For a specific class of tight-binding models, the relevant transport conditions and their signatures of non-Hermitian, nonreciprocal, and topological behavior are analytically tractable from a general perspective. We investigate …

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Recent Research Progresses Of Solid-State Lithium-Sulfur Batteries, Yu Luo, Ru-Qin Ma, Zheng-Liang Gong, Yong Yang Mar 2023

Recent Research Progresses Of Solid-State Lithium-Sulfur Batteries, Yu Luo, Ru-Qin Ma, Zheng-Liang Gong, Yong Yang

Journal of Electrochemistry

All solid-state lithium-sulfur batteries (ASSLSBs) are considered to be one of the most promising next-generation energy storage systems, due to the promises of high energy density and safety. Although the use of solid-state electrolytes could effectively suppress the "shuttle effect" and self-discharge of the conventional liquid lithium-sulfur (Li-S) battery, the commercialization of ASSLSBs has been seriously hampered by the electrolyte degradation, electrode/electrolyte interfacial deterioration, electrochemo-mechanical failure, lithium dendrite growth and electrode pulverization, etc. This paper provides a comprehensive review of recent research progresses on the solid-state electrolytes, sulfur-containing composite cathodes, lithium metal and lithium alloy anodes, and electrode/electrolyte interfaces in …

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Preface To The Special Issue On Lithium-Sulfur Batteries, Jia-Jia Chen, Ren-Jie Chen, Zhong Jin Mar 2023

Preface To The Special Issue On Lithium-Sulfur Batteries, Jia-Jia Chen, Ren-Jie Chen, Zhong Jin

Journal of Electrochemistry

No abstract provided.

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A Review On Solid-State Li-S Battery: From The Conversion Mechanism Of Sulfur To Engineering Design, Huan-Huan Jia, Chen-Ji Hu, Yi-Xiao Zhang, Li-Wei Chen Mar 2023

A Review On Solid-State Li-S Battery: From The Conversion Mechanism Of Sulfur To Engineering Design, Huan-Huan Jia, Chen-Ji Hu, Yi-Xiao Zhang, Li-Wei Chen

Journal of Electrochemistry

Lithium-sulfur (Li-S) batteries attract sustained attention because of their ultrahigh theoretical energy density of 2567 Wh·kg–1 and the actual value over 600 Wh·kg–1. Solid-state Li-S batteries (SSLSBs) emerge in the recent two decades because of the enhanced safety when compared to the liquid system. As for the SSLSBs, except for the difference in the conversion mechanism induced by the cathode materials themselves, the physical-chemical property of solid electrolytes (SEs) also significantly affects their electrochemical behaviors. On account of various reported Li-S batteries, the advantages and disadvantages in performance and the failure mechanism are discussed in this review. …

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Bimetallic Compound Catalysts With Multiple Active Centers For Accelerated Polysulfide Conversion In Li-S Batteries, Wu-Xing Hua, Jing-Yi Xia, Zhong-Hao Hu, Huan Li, Wei Lv, Quan-Hong Yang Mar 2023

Bimetallic Compound Catalysts With Multiple Active Centers For Accelerated Polysulfide Conversion In Li-S Batteries, Wu-Xing Hua, Jing-Yi Xia, Zhong-Hao Hu, Huan Li, Wei Lv, Quan-Hong Yang

Journal of Electrochemistry

Practical applications of lithium-sulfur (Li-S) batteries are hindered mainly by the low sulfur utilization and severe capacity fading derived from the polysulfide shuttling. Catalysis is an effective remedy to those problems by promoting the conversion of polysulfides to reduce their accumulation in the electrolyte, which needs the catalyst to have efficient adsorption ability to soluble polysulfides and high activity for their conversion. In this work, we have proposed a bimetallic compound of NiCo2S4 anchored onto sulfur-doped graphene (NCS@SG) to fabricate a catalytic interlayer for Li-S batteries. Compared to CoS, the NiCo2S4 demonstrated much higher …

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Coni-Based Bimetal-Organic Framework Derived Carbon Composites Multifunctionally Modified Separators For Lithium-Sulfur Batteries, Yan-Jie Wang, Hong-Yu Cheng, Ji-Yue Hou, Wen-Hao Yang, Rong-Wei Huang, Zhi-Cong Ni, Zi-Yi Zhu, Ying Wang, Ke-Yi Wei, Yi-Yong Zhang, Xue Li Mar 2023

Coni-Based Bimetal-Organic Framework Derived Carbon Composites Multifunctionally Modified Separators For Lithium-Sulfur Batteries, Yan-Jie Wang, Hong-Yu Cheng, Ji-Yue Hou, Wen-Hao Yang, Rong-Wei Huang, Zhi-Cong Ni, Zi-Yi Zhu, Ying Wang, Ke-Yi Wei, Yi-Yong Zhang, Xue Li

Journal of Electrochemistry

The commercial application of lithium-sulfur batteries (LSB) is still limited by the irreversible capacity fading caused by the shuttle of lithium polysulfides (LIPS). To address this issue, a bimetal (nickel, cobalt)-organic framework (MOF) derived carbon, (Ni, Co)/C, was prepared to modify the separator. The multifunctionally modified separator effectively captures LIPS, ensuring the stability and reversibility of sulfur fixation, while providing catalytic activity and improving ionic conductivity. The cobalt metal has a larger coordination number, more pore structure distribution, larger specific surface area, more surface C=O, and smaller particle size to achieve a large and rapid chemical sulfur fixation. The high …

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From Laboratory To Field: Unsupervised Domain Adaptation For Plant Disease Recognition In The Wild, Xinlu Wu, Xijian Fan, Peng Luo, Sruti Das Choudhury, Tardi Tjahjadi, Chunhua Hu Mar 2023

From Laboratory To Field: Unsupervised Domain Adaptation For Plant Disease Recognition In The Wild, Xinlu Wu, Xijian Fan, Peng Luo, Sruti Das Choudhury, Tardi Tjahjadi, Chunhua Hu

School of Computing: Faculty Publications

Plant disease recognition is of vital importance to monitor plant development and predicting crop production. However, due to data degradation caused by different conditions of image acquisition, e.g., laboratory vs. field environment, machine learning-based recognition models generated within a specific dataset (source domain) tend to lose their validity when generalized to a novel dataset (target domain). To this end, domain adaptation methods can be leveraged for the recognition by learning invariant representations across domains. In this paper, we aim at addressing the issues of domain shift existing in plant disease recognition and propose a novel unsupervised domain adaptation method via …

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Hsc-Independent Definitive Hematopoiesis Persists Into Adult Life, Samuel Cornelius, Noemi Valiente, Chika Nishida, Haizi Cheng, Augusto Latorre, W Jim Zheng, Joonsoo Kang, Jun Seita, David J Shih, Jia Qian Wu, Momoko Yoshimoto Mar 2023

Hsc-Independent Definitive Hematopoiesis Persists Into Adult Life, Samuel Cornelius, Noemi Valiente, Chika Nishida, Haizi Cheng, Augusto Latorre, W Jim Zheng, Joonsoo Kang, Jun Seita, David J Shih, Jia Qian Wu, Momoko Yoshimoto

Faculty, Staff and Student Publications

It is widely believed that hematopoiesis after birth is established by hematopoietic stem cells (HSCs) in the bone marrow and that HSC-independent hematopoiesis is limited only to primitive erythro-myeloid cells and tissue-resident innate immune cells arising in the embryo. Here, surprisingly, we find that significant percentages of lymphocytes are not derived from HSCs, even in 1-year-old mice. Instead, multiple waves of hematopoiesis occur from embryonic day 7.5 (E7.5) to E11.5 endothelial cells, which simultaneously produce HSCs and lymphoid progenitors that constitute many layers of adaptive T and B lymphocytes in adult mice. Additionally, HSC lineage tracing reveals that the contribution …

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Body Dimension And Length-Weigh Relationships Of Invasive Exotic Earthworm Species In Huron Mountains Forests, Paula Arroyo, Xiaoyong Chen, Timothy Gsell, John A. Yunger, Mary E. Carrington Mar 2023

Body Dimension And Length-Weigh Relationships Of Invasive Exotic Earthworm Species In Huron Mountains Forests, Paula Arroyo, Xiaoyong Chen, Timothy Gsell, John A. Yunger, Mary E. Carrington

Research Days

Invasive exotic earthworms have undesired ecological effects on structure, function, and biodiversity of forest ecosystems in the Great Lakes region. Biological parameters including body length, weight, growth rate, and regeneration patterns of earthworms are necessary to understand their life cycle and impacts on ecological processes such as nutrient biogeochemistry cycling and carbon sequestration in the forests, as well as for forest management practices. In this work, earthworms were surveyed in main forest types of the Huron Mountains Preserve of Michigan, Upper Peninsula during the period of May 2021 to October 2022. Earthworms were captured from established sampling quadrates using a …

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From Space To The Streets: Leveraging Satellite Data For Air Pollution, Health, And Justice, Gaige Kerr Mar 2023

From Space To The Streets: Leveraging Satellite Data For Air Pollution, Health, And Justice, Gaige Kerr

Sustainability Seminar Series

Ambient air disproportionately affects marginalized and minoritized communities in the United States. Satellite remote sensing provides crucial data needed to assess air pollution at a high spatial resolution and further understand the drivers, extent, and impacts of this form of environmental injustice. I provide a few vignettes to highlight how recent advances in remote sensing can inform and improve our understanding of environment health. First, satellite measurements and datasets that incorporate satellite data demonstrate the inequitable distribution of traffic-related pollutants such as nitrogen dioxide and fine particulate matter and how disparities have changed during recent years, including during the COVID-19 …

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Electric Utility Performance In The Mountain West, Hira Ahmed, Miguel Soriano Ralston, Caitlin J. Saladino, William E. Brown Jr. Mar 2023

Electric Utility Performance In The Mountain West, Hira Ahmed, Miguel Soriano Ralston, Caitlin J. Saladino, William E. Brown Jr.

Environment

This fact sheet examines select data from the Citizens Utility Board (CUB) report, “Electric Utility Performance: A State-By-State Review,” which provides information on the affordability, reliability, and environmental responsibility of electric utility energy consumption. The original report provides a comprehensive state-by-state profile of utility performance in the United States. These data were originally reported by the Energy Information Administration (EIA) of the U.S. Department of Energy. This federal entity is responsible for the aggregation and dissemination of information about the American energy industry. This fact sheet highlights energy sources, affordability, reliability, and environmental impact of energy consumption in the Mountain …

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Paek- And Pes-Like Perarylated Phosphonium Ionenes: Synthesis, Thermal Properties, And Conductivity, Samantha M. Sims, Hannah Brown, Jalisha R. Hunter, R. Daniel Johnson, Rachel E. Whittaker, Kevin M. Miller Mar 2023

Paek- And Pes-Like Perarylated Phosphonium Ionenes: Synthesis, Thermal Properties, And Conductivity, Samantha M. Sims, Hannah Brown, Jalisha R. Hunter, R. Daniel Johnson, Rachel E. Whittaker, Kevin M. Miller

Faculty & Staff Research and Creative Activity

Perarylated phosphonium salts are known to exhibit high degrees of thermal stability, often in excess of 400 °C. Here, the thermal and conductive properties of a series of perarylated phosphonium ionenes, prepared utilizing a PAEK-/PES-like synthetic approach, is described. All of the ionenes were found to display Td5% values in excess of 365 °C. Structural changes in the polymer backbone were found to have a prominent impact on Tg, with the meta-analogs exhibiting values ∼45 °C below the para-analogs, emphasizing the significant impact that solid-state packing can have on thermal transitions. All of the phosphonium ionenes …

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Regular Solutions To Elliptic Equations, Alfonso Castro, Jon T. Jacobsen Mar 2023

Regular Solutions To Elliptic Equations, Alfonso Castro, Jon T. Jacobsen

All HMC Faculty Publications and Research

A review of results and techniques on the existence of regular radial solutions to second order elliptic boundary value problems driven by linear and quasilinear operators is presented. Of particular interest are results where the solvability of a given elliptic problem can be analyzed by the relationship between the spectrum of the operator and the behavior of the nonlinearity near infinity and at zero. Energy arguments and Pohozaev type identities are used extensively in that analysis. An appendix with a proof of the contraction mapping principle best suited for using continuous dependence to ordinary differential equations on initial conditions is …

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Neutrosophic Mcdm Methodology For Assessment Risks Of Cyber Security In Power Management, Ahmed M. Abdelmouty, Ahmed Abdel-Monem Mar 2023

Neutrosophic Mcdm Methodology For Assessment Risks Of Cyber Security In Power Management, Ahmed M. Abdelmouty, Ahmed Abdel-Monem

Neutrosophic Systems with Applications

Every day, new reports of cyberattacks on interconnected control systems emerge. The vulnerability of their communication mechanism makes similar control systems a target for malicious outsiders. Protecting sensitive data and maintaining network reliability and availability are two of the main reasons why network security is so important. Strong and dependable network security strategies use a number of safeguards to protect users and businesses from malware and cyber assaults like distributed denial of service. A safety analysis is an essential step that must precede the introduction of any security measures. There hasn't been much experience with cyberattacks on power control systems …

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Ceers Key Paper. Ii. A First Look At The Resolved Host Properties Of Agn At 3 < Z < 5 With Jwst, Dale D. Kocevski, Guillermo Barro, Elizabeth J. Mcgrath, Steven L. Finkelstein, Micaela B. Bagley, Henry C. Ferguson, Shardha Jogee, Guang Yang, Mark Dickinson, Nimish P. Hathi, Bren E. Backhaus, Eric F. Bell, Laura Bisigello, Véronique Buat, Denis Burgarella, Caitlin M. Casey, Nikko J. Cleri, M. C. Cooper, Luca Costantin, Darren Croton, Emanuele Daddi, Adriano Fontana Mar 2023

Ceers Key Paper. Ii. A First Look At The Resolved Host Properties Of Agn At 3 < Z < 5 With Jwst, Dale D. Kocevski, Guillermo Barro, Elizabeth J. Mcgrath, Steven L. Finkelstein, Micaela B. Bagley, Henry C. Ferguson, Shardha Jogee, Guang Yang, Mark Dickinson, Nimish P. Hathi, Bren E. Backhaus, Eric F. Bell, Laura Bisigello, Véronique Buat, Denis Burgarella, Caitlin M. Casey, Nikko J. Cleri, M. C. Cooper, Luca Costantin, Darren Croton, Emanuele Daddi, Adriano Fontana

Pacific Faculty Work

We report on the host properties of five X-ray-luminous active galactic nuclei (AGN) identified at 3 < z < 5 in the first epoch of imaging from the Cosmic Evolution Early Release Science Survey. Each galaxy has been imaged with the JWST Near-Infrared Camera, which provides rest-frame optical morphologies at these redshifts. We also derive stellar masses and star formation rates for each host by fitting its spectral energy distribution using a combination of galaxy and AGN templates. We find that three of the AGN hosts have spheroidal morphologies, one is a bulge-dominated disk, and one is dominated by pointlike emission. None are found to show strong morphological disturbances that might indicate a recent interaction or merger event. When compared to a sample of mass-matched inactive galaxies, we find that the AGN hosts have morphologies that are less disturbed and more bulge-dominated. Notably, all four of the resolved hosts have rest-frame optical colors consistent with a quenched or poststarburst stellar population. The presence of AGN in passively evolving galaxies at z > 3 is significant because a rapid feedback mechanism is required in most semianalytic models and cosmological simulations to explain the growing population of massive quiescent galaxies observed at these redshifts. Our findings show that AGN can continue to inject energy into these systems after their star formation is curtailed, potentially heating their halos and preventing renewed star formation. Additional observations will be needed to determine what role this feedback may play in helping to quench these systems and/or maintain their quiescent state.

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Using Satellites To Map The Urban Heat Island Effect And Using Products To Generate Public Action In Harrisonburg, Trevor Brooks, Timothy A. Kreps Mar 2023

Using Satellites To Map The Urban Heat Island Effect And Using Products To Generate Public Action In Harrisonburg, Trevor Brooks, Timothy A. Kreps

ASPIRE 2023

The Urban Heat Island effect (UHI) is a phenomenon where urban centers are hotter than their surrounding rural counterparts. Ever since it was first discovered there have been a variety of methods of mapping this effect from using terrestrial sensors to satellites. This study attempts to evaluate different mapping methods, specifically two different satellite methods (ECOSTRESS and MODIS). As well as a community driven mapping method that involved terrestrial sensors attached to cars. This study then discusses remedies to the UHI and documents efforts to remedy it through a partnership between researchers, the community, and the city of Harrisonburg as …

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Developing And Analyzing An Explicit Unconditionally Stable Finite Element Scheme For An Equivalent Bérenger’S Pml Model, Yunqing Huang, Jichun Li, Xin Liu Mar 2023

Developing And Analyzing An Explicit Unconditionally Stable Finite Element Scheme For An Equivalent Bérenger’S Pml Model, Yunqing Huang, Jichun Li, Xin Liu

Mathematical Sciences Faculty Research

The original Bérenger’s perfectly matched layer (PML) was quite effective in simulating wave propagation problem in unbounded domains. But its stability is very challenging to prove. Later, some equivalent PML models were developed by Bécache and Joly [ESAIM: M2AN 36 (2002) 87–119] and their stabilities were established. Hence studying and developing efficicent numerical methods for solving those equivalent PML models are needed and interesting. Here we propose a novel explicit unconditionally stable finite element scheme to solve an equivalent Bérenger’s PML model. Both the stability and convergence analysis are proved for the proposed scheme. Numerical results justifying the theoretical …

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