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Nitrogen enhanced drainage of CO2 rich coal seams for mining

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International Journal of Mining science and Technology 2017年第5期27卷 755-761页

作者： luke D.Connell Regina sander Michael Camilleri Deasy Heryanto Zhejun Pan nicholas Lupton CsIRO Energy ClaytonVictoria 3169Australia

Coal seams with high CO_2 gas contents can be difficult to drain gas for outburst management. Coal has a high affinity for CO_2 with adsorption capacities typically twice that of CH_4. This paper presents an analysis of nitrogen injection into coal to enhance drainage of high CO_2 gas contents. Core flooding experiments were conducted where nitrogen was injected into coal core samples from two Australian coal mining basins with initial CO_2 gas contents and pressures that could be encountered during underground mining. Nitrogen effectively displaced the CO_2 with mass balance analysis finding there was only approximately 6%–7% of the original CO_2 gas content residual at the end of the core flood. Using a modified version of the sIMED II reservoir simulator, the core flooding experiments were history matched to determine the nitrogen and methane sorption times. It was found that a triple porosity model(a simple extension of the Warren and Root dual porosity model) was required to accurately describe the core flood observations. The estimated model properties were then used in reservoir simulation studies comparing enhanced drainage with conventional drainage with underground in seam boreholes. For the cases considered, underground in seam boreholes were found to provide shorter drainage lead times than enhanced drainage to meet a safe gas content for outburst management.

关键词： Gas drainage High CO2 ECBM Reservoir simulation

Assessment of strain bursting in deep tunnelling by using the finite-discrete element method

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第1期11卷 12-37页

作者： Ioannis Vazaios Mark s.Diederichs nicholas Vlachopoulos Department of Ceological saences and Ceological Engineering Queen's UniversityKingstonCanada

Rockbursting in deep tunnelling is a complex phenomenon posing significant challenges both at the design and construction stages of an underground excavation within hard rock masses and under high in situ stresses. While local experience, field monitoring, and informed data-rich analysis are some of the tools commonly used to manage the hazards and the associated risks, advanced numerical techniques based on discontinuum modelling have also shown potential in assisting in the assessment of rockbursting. In this study, the hybrid finite-discrete element method(FDEM) is employed to investigate the failure and fracturing processes, and the mechanisms of energy storage and rapid release resulting in bursting, as well as to assess its utility as part of the design process of underground *** the calibration of the numerical model to simulate a deep excavation in a hard, massive rock mass, discrete fracture network(DFN) geometries are integrated into the model in order to examine the impact of rock structure on rockbursting under high in situ stresses. The obtained analysis results not only highlight the importance of explicitly simulating pre-existing joints within the model, as they affect the mobilised failure mechanisms and the intensity of strain bursting phenomena, but also show how the employed joint network geometry, the field stress conditions, and their interaction influence the extent and depth of the excavation induced damage. Furthermore, a rigorous analysis of the mass and velocity of the ejected rock blocks and comparison of the obtained data with well-established semi-empirical approaches demonstrate the potential of the method to provide realistic estimates of the kinetic energy released during bursting for determining the energy support demand.

关键词： Rockburst Finite-discrete element method(FDEM) Deep tunnelling Hard rock excavations Brittle fracturing Discrete fracture network(DFN)

Machine learning for the discovery of molecular recognition based on single-walled carbon nanotube corona-phases

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npj Computational Materials 2022年第1期8卷 1265-1277页

作者： Xun Gong nicholas Renegar Retsef Levi Michael s.strano Massachusetts Institute of Technology Department of Chemical EngineeringCambridgeMAUSA Massachusetts Institute of Technology Operations Research CenterCambridgeMAUSA Massachusetts Institute of Technology Sloan School of ManagementCambridgeMAUSA

Nanoparticle corona phase(CP)design offers a unique approach toward molecular recognition(MR)for sensing ***-walled carbon nanotube(sWCNT)CPs can additionally transduce MR through its band-gap photoluminescence(PL).While DNA oligonucleotides have been used as sWCNT CPs,no generalized scheme exists for MR prediction de novo due to their sequence-dependent three-dimensional *** work generated the largest DNA-sWCNT PL response library of 1408 elements and leveraged machine learning(ML)techniques to understand MR and DNA sequence dependence through local(LFs)and high-level features(HLFs).Out-of-sample analysis of our ML model showed significant correlations between model predictions and actual sensor responses for 6 out of 8 experimental *** HLF combinations were found to be uniquely correlated with different ***,models utilizing both LFs and HLFs show improvement over that with HLFs alone,demonstrating that DNA-sWCNT CP engineering is more complex than simply specifying molecular properties.

关键词： walled carbon utilizing

Predicting phosphorus sorption isotherm parameters in soil using data of routine laboratory tests

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Pedosphere 2021年第5期31卷 694-704页

作者： Kathleen s.DUNNE nicholas M.HOLDEN Karen DALY Teagasc Johnstown CastleEnvironmental Research CentreCo.Wexford Y35TC97(Ireland) UCD school of Biosystems and Food Engineering University College DublinBelfieldDublin 4 D04VIW8(Ireland)

Knowledge of phosphorus(P)sorption dynamics across different soil types could direct agronomic and environmental management of *** objective of this study was to predict P isotherm parameters for a national soil population using data of routine laboratory *** and Freundlich sorption parameters were calculated from two different ranges(0-25 and 0-50 mg P L^(-1))using an archive of representative agricultural soil types from *** linear regression(MLR)identified labile forms of aluminium(Al)and iron(Fe),organic matter(OM),cation exchange capacity(CEC),and clay as significant *** and Freundlich sorption capacities,Freundlich affinity constant,and Langmuir buffer capacity were predicted reliably,with R^(2) of independent validation>*** isotherm parameters were predicted from P sorbed at a single concentration of 50 mg P L^(-1)(s_(50)).An MLR prediction of P sorption maximum in the 0-50 mg P L-1 range was achieved,to an accurate standard,using s_(50),OM,and Mehlich-3 Fe(R^(2) of independent calibration and validation being 0.91 and 0.95,respectively).Using Giles’four shapes of isotherms(C,L,H,and s),L non-strict-and C-shaped isotherm curves accounted for 64% and 27% of the soils,*** clustering identified a separation of isotherm curves influenced by two ranges of Mehlich-3 *** with a low range of Mehlich-3 Al(2.5-698 mg kg^(-1))had no incidence of rapid sorption(C shape).single point indices,Al,or available soil data make the regression approach a feasible way of predicting Langmuir parameters that could be included with standard agronomic soil P testing.

关键词： available phosphorus binding fertilizer soil test sorption maximum

Conjunctions and/or Disjunctions： Radical Empiricism in the History of Philosophy

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Frontiers of Philosophy in China 2014年第1期9卷 130-148页

作者： nicholas s. Brasovan Department of Philosophy and Religion University of Central Arkansas AR 72035 USA

William James challenged the traditions of British Empiricism （Hume） on one hand and German Idealism （Kant and Hegel） on the other. James＇＂Radical Empiricism＂ is a via media （＂middle road＂） between these divergent positions. His central points of contention are the ontological status of relationships and the correct analysis of experience. British Empiricism leaves us with a world of separate, particular facts, based on atomic sense impressions. Idealists, on the other hand, claim that all worldly phenomena are conjoined by one rational principle. According to James＇ account, neither side recognizes that both conjunctive and disjunctive relations are integral to experience. Furthermore, James＇ critique proved to influence A. N. Whitehead＇s philosophy of experience and orientation toward Hume and Kant. This essay situates James＇ philosophy in this polemical and historical context.

关键词： William James Radical Empiricism American philosophy Kant,Whitehead Hume Hegel

User-Level Device Drivers： Achieved Performance

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Journal of Computer science & Technology 2005年第5期20卷 654-664页

作者： Ben Leslie Peter Chubb nicholas Fitzroy-Dale stefan Gotz Charles Gray luke Macpherson Daniel Potts Yue-Ting shen Kevin Elphinstone Gernot Heiser National ICT Australia and school of Computer science and Engineering University of New South Wales Sydney 2052 Australia Wilhelm-schickard-Institute for Computer science University of Tǖbingen D-72076 Tǖbingen Germany

Running device drivers as unprivileged user-level code, encapsulated into their own process, has often been proposed as a technique for increasing system robustness. However, in the past, systems based on user-level drivers have generally exhibited poor I/O performance. Consequently, user-level device drivers have never caught on to any significant degree. In this paper we demonstrate that it is possible to build systems which employ user-level device drivers, without significant performance degradation, even for high-bandwidth devices such as Gigabit Ethernet.

关键词： device drivers operating systems performance reliability

Disease spectrum and use of cholecystolithotomy in gallstone ileus

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Hepatobiliary & Pancreatic Diseases International 2012年第5期11卷 553-557页

作者： nicholas E Williams Justin s Gundara sophia Roser Jaswinder s samra Upper Gastrointestinal surgical Unit Royal North Shore HospitalUniversity of SydneySt.LeonardsSydneyNSW 2065Australia

BACKGROUND: Gallstone ileus is a heterogeneous and highly morbid condition that suffers from a lack of consensus regarding the timing and approach to management of the biliary tree and associated fistula. METHODs: We report three cases that demonstrate the spectrum of gallstone ileus with classical examples of both Barnard’s and Bouveret’s syndromes. Clinical presentation diagnostic imaging, surgical technique and outcome are discussed. REsULTs: One patient with Barnard’s syndrome presented with recurrent gallstone ileus. To minimize the risks of complex, definitive biliary surgery and avoid further recurrent episodes, a cholecystolithotomy was performed with effect Two cases of Bouveret’s syndrome were successfully managed with enterolithotomy/cholecystectomy and multivisceral resection respectively, thus highlighting the diverse nature of this disease and management options. CONCLUsIONs: Following enterolithotomy, potentially morbid definitive one-stage surgery in typically compromised, elderly patients needs to be weighed against the risk of recurrence and ongoing biliary pathology. We suggest the use of open cholecystolithotomy for the removal of residual gallstones when the patient is not suitable for definitive biliary surgery.

关键词： cholecystectomy biliary tract disease gallstone ileus biliary tract surgery

PROJECT MANAGEMENT:RECENT DEVELOPMENTs AND REsEARCH OPPORTUNITIEs

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Journal of systems science and systems Engineering 2012年第2期21卷 129-143页

作者： nicholas G.HALL Department of Management sciences Fisher College of Business The Ohio State UniversityUSA

This paper studies the business process known as project management. This process has exhibited a remarkable growth in business interest over the last 15 years, as demonstrated by a 1000% increase in membership in the Project Management Institute since 1996. This growth is largely attributable to the emergence of many new diverse business applications that can be successfully managed as projects. The new applications for project management include IT implementations, research and development, new product and service development, corporate change management, and software development. The characteristics of modem projects are typically very different from those of traditional projects such as construction and engineering, which necessitates the development of new project management techniques. We discuss these recent practical developments. The history of project management methodology is reviewed, from CPM and PERT to the influential modem directions of critical chain project management and agile methods. We identify one important application area for future methodological change as new product and service development. A list of specific research topics within project management is discussed. The conclusions suggest the existence of significant research opportunities within project management.

关键词： Project management overview recent practical developments opportunities for research

Longitudinal bicyclist,driver,and pedestrian perceptions of autonomous vehicle communication strategies

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Journal of Traffic and Transportation Engineering(English Edition) 2023年第1期10卷 31-44页

作者： nicholas N.Ferenchak Department of Civil Construction&Environmental EngineeringUniversity of New MexicoAlbuquerqueNM 87131USA

We sought to better understand how autonomous vehicle(AV)communication strategies impact human road users’*** specifically,we explored the impact of different external human-machine interface(eHMI)designs on task load,comfort,trust,and *** accomplish this,we created virtual reality(VR)scenarios where human participants interacted with AVs in biking,driving,and pedestrian *** were brought back after initial testing to explore acclimation and learning *** designs included a text-based grille eHMI,a text-based roof eHMI,a text-based driver-side door eHMI,anon-textual LED windshield strip eHMI,and a non-textual side mirror arrow *** presence of an eHMI was the strongest positive predictor of comfort,trust,and acceptance outcomes in the statistical models when controlling for all other *** was a clear divide between text-based eHMIs and non-text eHMIs with text-based eHMIs experiencing better perception *** LED Windshield experienced the worst perception *** were perception acclimation effects detected which were most notable for task load(which decreased over time)and comfort(which increased over time).Perception scores for the different eHMI designs tended to cluster over ***,the acclimation effects had less of an impact than the presence of an *** outcomes had weaker relationships with participant characteristics than with AV *** suggest that eHMI presence and design,AV behavior,and acclimation are most impactful in terms of perceptions.

关键词： Vehicle automation Communication Human-automation interaction Technology acceptance Virtual reality