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Effects of longwall-induced stress and deformation on the stability and mechanical integrity of shale gas wells drilled through a longwall abutment pillar

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International Journal of Mining Science and Technology 2017年第1期27卷 115-120页

作者： daniel W.h.Su National Institute for Occupational Safety and health Bruceton 15236PAUSA

This paper presents the results of a comprehensive study conducted by CONSOL Energy, Marcellus Shale Coalition, and Pennsylvania Coal Association to evaluate the effects of longwall-induced subsurface deformations on the mechanical integrity of shale gas wells drilled over a longwall abutment *** primary objective is to demonstrate that a properly constructed gas well in a standard longwall abutment pillar can maintain mechanical integrity during and after mining operations. A study site was selected over a southwestern Pennsylvania coal mine, which extracts 457-m-wide longwall faces under about 183 m of cover. Four test wells and four monitoring wells were drilled and installed over a 38-m by84-m centers abutment pillar. In addition to the test wells and monitoring wells, surface subsidence measurements and underground coal pillar pressure measurements were conducted as the 457-m-wide longwall panels on the south and north sides of the abutment pillar were mined by. To evaluate the resulting coal protection casing profile and lateral displacement, three separate 60-arm caliper surveys were conducted. This research represents a very important step and initiative to utilize the knowledge and science obtained from mining research to improve miner and public safety as well as the safety and health of the oil and gas industries.

关键词： Gas well Casing Abutment pillar Stability Safety and health Instrumentation Numerical simulation

simplifyEnrichment:A Bioconductor Package for Clustering and Visualizing Functional Enrichment Results

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Genomics, Proteomics & Bioinformatics 2023年第1期21卷 190-202页

作者： Zuguang Gu daniel hübschmann Molecular Precision Oncology Program National Center for Tumor Diseases(NCT)HeidelbergD-69120 HeidelbergGermany heidelberg Institute of Stem Cell Technology and Experimental Medicine(hI-STEM) D-69120 HeidelbergGermany German Cancer Consortium(DKTK) D-69120 HeidelbergGermany Department of Pediatric Immunology Hematology and OncologyUniversity Hospital HeidelbergD-69120 HeidelbergGermany

Functional enrichment analysis or gene set enrichment analysis is a basic bioinformatics method that evaluates the biological importance of a list of genes of ***,it may produce a long list of significant terms with highly redundant information that is difficult to *** tools to simplify enrichment results by clustering them into groups either still produce redundancy between clusters or do not retain consistent term similarities within *** propose a new method named binary cut for clustering similarity matrices of functional *** comprehensive benchmarks on both simulated and real-world datasets,we demonstrated that binary cut could efficiently cluster functional terms into groups where terms showed consistent similarities within groups and were mutually exclusive between *** compared binary cut clustering on the similarity matrices obtained from different similarity measures and found that semantic similarity worked well with binary cut,while similarity matrices based on gene overlap showed less consistent *** implemented the binary cut algorithm in the R package simplifyEnrichment,which additionally provides functionalities for visualizing,summarizing,and comparing the *** simplifyEnrichment package and the documentation are available at https://***/packages/simplifyEnrichment/.

关键词： Functional enrichment Simplify enrichment Clustering R/Bioconductor Software Visualization

Disaster Risk Resilience:Conceptual Evolution,Key Issues,and Opportunities

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International Journal of Disaster Risk Science 2022年第3期13卷 330-341页

作者： Marie-hélène Graveline daniel Germain Institut des Sciences de l’Environnement(ISE) Universitédu QuébecàMontréalMontréalH3C 3P8Canada Department of Geography Universitédu QuébecàMontréalMontréalH3C 3P8Canada

Resilience has become a cornerstone for risk management and disaster ***,it has evolved extensively both etymologically and conceptually in time and across scientific *** concept has been(re)shaped by the evolution of research and practice *** the opposite of vulnerability for a long time,resilience was first defined as the ability to resist,bounce back,cope with,and recover quickly from the impacts of *** avoid the possible return to conditions of vulnerability and exposure to hazards,the notions of post-disaster development,transformation,and adaptation(build back better)and anticipation,innovation,and proactivity(bounce forward)were then ***,resilience is characterized by a multitude of components and several *** present a selection of 25 components used to define resilience,and an interesting linkage emerges between these components and the dimensions of risk management(prevention,preparedness,response,and recovery),offering a perspective to strengthen resilience through the development of *** its potential,resilience is subject to challenges regarding its operationalization,effectiveness,measurement,credibility,equity,and even its ***,it offers applicability and opportunities for local communities as well as an interdisciplinary look at global challenges.

关键词： Community Disaster risk Resilience Sustainable development

Temporal scatterplots

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Computational Visual Media 2020年第4期6卷 385-400页

作者： Or Patashnik Min Lu Amit h.Bermano daniel Cohen-Or Tel-Aviv University Tel-AvivIsrael Shenzhen University ShenzhenChina

Visualizing high-dimensional data on a 2D canvas is generally *** becomes significantly more difficult when multiple time-steps are to be presented,as the visual clutter quickly ***,the challenge to perceive the significant temporal evolution is even *** this paper,we present a method to plot temporal high-dimensional data in a static scatterplot;it uses the established PCA technique to project data from multiple *** key idea is to extend each individual displacement prior to applying PCA,so as to skew the projection process,and to set a projection plane that balances the directions of temporal change and spatial *** present numerous examples and various visual cues to highlight the data trajectories,and demonstrate the effectiveness of the method for visualizing temporal data.

关键词： scatterplot temporal data visual clutter principle component analysis(PCA)

Effect of slab width on choice of appropriate casting speed in steel production

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Journal of Iron and Steel Research International 2022年第1期29卷 71-79页

作者： daniel Christopher Merten Marc-Thorsten hütt Yilmaz Uygun Department of Mathematics and Logistics Jacobs University BremenBremen 28759Germany Department of Life Sciences and Chemistry Jacobs University BremenBremen 28759Germany

In steel continuous casting(CC),the choice of the appropriate speed at which the slab is cast can be influenced by many different factors and *** the slab thickness seems to have the biggest impact,other features like the slab width have been consistently *** fact,the slab width practically limits the casting speed via the mass flow constraint which governs the input and output balance at the ***,we present a case study that aims at analyzing steel production data from the perspective of casting speed *** studying the speed fluctuations of an industrial CC machine,we identify a strategic regime change toward a stricter consideration of the mass flow *** regime change manifests itself in a significant increase in the correlation between the actual casting speed and the maximal speed associated with the mass flow *** the surface,taking greater account of the input and output balance at the tundish has reduced the productivity of the continuous caster;however,one can argue that the lessened yield is compensated by a diminished risk of eventual slab *** the perspective of this trade-off,we establish a visualization technique that enables us to pinpoint the boundary beyond which one strategic regime becomes economically more advantageous than the other.

关键词： Continuous casting Casting speed Slab width Slab thickness Mass flow constraint Machine length constraint

Parkland trees on smallholder farms ameliorate soil physical-chemical properties in the semi-arid area of Tigray,Ethiopia

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Journal of Arid Land 2024年第1期16卷 1-13页

作者： Selam LJALEM Emiru BIRhANE Kassa TEKA daniel h BERhE Department of Land Resources Management and Environmental Protection College of Dryland Agriculture and Natural ResourcesMekelle UniversityMekelle 231Ethiopia Institute of Climate and Society Mekelle UniversityMekelle 231Ethiopia Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life Sciences(NMBU)Ås 1432Norway Department of Natural Resources Management Adigrat UniversityAdigrat 50Ethiopia

Proposed agroforestry options should begin with the species that farmers are most familiar with,which would be the native multipurpose trees that have evolved under smallholder farms and socioeconomic *** African birch(Anogeissus leiocarpa(DC.)Guill.&Perr.)and pink jacaranda(Stereospermum kunthianum Cham.)trees are the dominant species in the agroforestry parkland system in the drylands of Tigray,*** farmers highly value these trees for their multifunctional uses including timber,firewood,charcoal,medicine,*** trees also could improve soil ***,the amount of soil physical and chemical properties enhanced by the two species must be determined to maintain the sustainable conservation of the species in the parklands and to scale up to similar agroecological ***,we selected twelve isolated trees,six from each species that had similar dendrometric characteristics and were growing in similar environmental *** divided the canopy cover of each tree into three radial distances:mid-canopy,canopy edge,and canopy gap(control).At each distance,we took soil samples from three different *** collected 216 soil samples(half disturbed and the other half undisturbed)from each canopy position and soil *** density(BD),soil moisture content(SMC),soil organic carbon(SOC),total nitrogen(TN),available phosphorus(AP),available potassium(AK),p h,electrical conductivity(EC),and cation exchange capacity(CEC)were *** revealed that soil physical and chemical properties significantly improved except for soil texture and EC under both species,CEC under ***,and soil p h under ***,all the studied soils were improved under both species canopy as compared with canopy ***,TN,AP,and AK under canopy of these trees were respectively 24.1%,11.1%,55.0%,and 9.3% higher than those soils under *** two parkland agroforestry species significantly enhanced soil fertility near the canopy of top

关键词： agroforestry bulk density carbon stock dispersed tree soil texture tree canopy

Computational modelling of magnesium degradation in simulated body fluid under physiological conditions

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Journal of Magnesium and Alloys 2022年第4期10卷 965-978页

作者： Berit Zeller-Plumhoff Tamadur AlBaraghtheh daniel höche Regine Willumeit-Römer helmholtz-Zentrum hereon Gmbh Institute of Metallic BiomaterialsMax-Planck-Straße 1Geesthacht21502Germany helmholtz-Zentrum hereon Gmbh Institute of Surface ScienceMax-Planck-Straße 1Geesthacht21502Germany

Magnesium alloys are highly attractive for the use as temporary implant materials, due to their high biocompatibility and ***, the prediction of the degradation rate of the implants is difficult, therefore, a large number of experiments are required. Computational modelling can aid in enabling the predictability, if sufficiently accurate models can be established. This work presents a generalized model of the degradation of pure magnesium in simulated body fluid over the course of 28 days considering uncertainty aspects. The model includes the computation of the metallic material thinning and is calibrated using the mean degradation depth of several experimental datasets simultaneously. Additionally, the formation and precipitation of relevant degradation products on the sample surface is modelled, based on the ionic composition of simulated body fluid. The computed mean degradation depth is in good agreement with the experimental data(NRMSE=0.07). however, the quality of the depth profile curves of the determined elemental weight percentage of the degradation products differs between elements(such as NRMSE=0.40 for phosphorus vs. NRMSE=1.03 for magnesium). This indicates that the implementation of precipitate formation may need further developments. The sensitivity analysis showed that the model parameters are correlated and which is related to the complexity and the high computational costs of the model. Overall, the model provides a correlating fit to the experimental data of pure Mg samples of different geometries degrading in simulated body fluid with reliable error estimation.

关键词： Biodegradation Magnesium Computational modelling Corrosion Uncertainty quantification Kriging

Effect of longwall-induced subsurface deformations on shale gas well casing stability under deep covers

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International Journal of Mining Science and Technology 2019年第1期29卷 3-8页

作者： daniel W.h.Su Peter Zhang Mark Van Dyke Todd Minoski Center for Disease Control and Prevention(CDC) National Institute for Occupational Safety and Health(NIOSH)Pittsburgh Mining Research Division(PMRD)

This paper presents the results of a 2017 study conducted by the National Institute for Occupational Safety and health(NIOSh), Pittsburgh Mining Research Division(PMRD), to evaluate the effects of longwall-induced subsurface deformations within a longwall abutment pillar under deep cover. The 2017 study was conducted in a southwestern Pennsylvania coal mine, which extracts 457 m-wide longwall panels under 361 m of cover. One 198 m-deep, in-place inclinometer monitoring well was drilled and installed over a 45 m by 84 m center abutment pillar. In addition to the monitoring well, surface subsidence measurements and underground coal pillar pressure measurements were conducted as the 457 m-wide longwall panel on the south side of the abutment pillar was being mined. Prior to the first longwall excavation, a number of simulations using FLAC3D^(TM) were conducted to estimate surface subsidence, increases in underground coal pillar pressure, and subsurface horizontal displacements in the monitoring well. Comparisons of the pre-mining FLAC3D simulation results and the surface, subsurface,and underground instrumentation results show that the measured in-place inclinometer casing deformations are in reasonable agreement with those predicted by the 3D finite difference models. The measured surface subsidence and pillar pressure are in excellent agreement with those predicted by the 3D *** from this 2017 research clearly indicate that, under deep cover, the measured horizontal displacements within the abutment pillar are approximately one order of magnitude smaller than those measured in a 2014 study under medium cover.

关键词： Longwall Deformations Shale gas wells Casing Safety and health

Numerical Modeling of One-Dimensional Binary Solidification with a Mushy Layer Evolution

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Numerical Mathematics(Theory,Methods and Applications) 2012年第2期5卷 157-185页

作者： daniel Lee Dmitri Alexandrov h.-N.huang Department of Applied Mathematics Tunghai UniversityTaichungTaiwan 40704 Ural Federal University Department of Mathematical PhysicsLenin ave.51Ekaterinburg 620083Russian Federation

The numerical modeling of a binary solidification with a mushy layer mechanism is considered in this *** nonlinear coupled system of equations describes the heat and mass diffusions of a one-dimensional spatial variable in the semiinfinite *** formulated is a transformed system in a finite *** propose numerical methods for solving the nonlinear system using a threshold strategy based on fixed computation-domain *** calculated results and those from the LeadEx field experiment are well-matched in their tendencies.

关键词： Direct numerical simulation heat and mass transfer Mushy layer Solidification Stefan problem