142 research outputs found

    Further results on nearly Kirkman triple systems with subsystems

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    AbstractIn this paper we further discuss the embedding problem for nearly Kirkman triple systems and get the result that: (1) For u≡v≡0(mod6), v⩾78, and u⩾3.5v, there exists an NKTS(u) containing a sub-NKTS(v). (2) For v=18,24,30,36,42,48,54,60,66 or 72, there exists an NKTS(u) containing a sub-NKTS(v) if and only if u≡0(mod6) and u⩾3v

    3D Behavior of Schottky Barriers of 2D Transition-Metal Dichalcogenides.

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    The transition metal dichalcogenides (TMDs) are two-dimensional layered solids with van der Waals bonding between layers. We calculate their Schottky barrier heights (SBHs) using supercell models and density functional theory. It is found that the SBHs without defects are quite strongly pinned, with a pinning factor S of about S = 0.3, a similar value for both top and edge contact geometries. This arises because there is direct bonding between the contact metal atoms and the TMD chalcogen atoms, for both top and edge contact geometries, despite the weak interlayer bonding in the isolated materials. The Schottky barriers largely follow the metal induced gap state (MIGS) model, like those of three-dimensional semiconductors, despite the bonding in the TMDs being largely constrained within the layers. The pinning energies are found to be lower in the gap for edge contact geometries than for top contact geometries, which might be used to obtain p-type contacts on MoS2.The authors acknowledge the financial support of EPSRC Grant EP/J011592.This is the author accepted manuscript. The final version is available from the American Chemical Society via http://dx.doi.org/10.1021/acsami.5b0689

    Tracking and fleet optimization of Reusable Transport Items in the shipping industry

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    Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 77-78).This thesis explores the strategies, methodologies and tools for an optimal management of Reusable Transport Items, such as containers or chassis, in an extensive multi-depots network. We use an ocean shipping company operating globally to propose a broad, comprehensive and integrated system for an optimal management of the fleet, embracing technology, processes and monitoring system. The ability to track these assets is the first step to visibility and fleet optimization and we will question the opportunity for a company to invest in a real time tracking technology. In highly complex logistic networks, the challenge is to get the right equipment at the right place at the right time, in a cost efficient manner and with a fleet size as small as possible. Beyond increased visibility through tracking capabilities, we show that choosing an appropriate utilization metrics helps identify and quantify other areas of improvement. Using actual data, we evaluate to what extent the fleet size can be reduced by improving asset utilization and how leasing also impacts operating costs. We also show how the structural imbalance of trade (some regions being net exporters while others are net importers) impacts both global repositioning policy and local inventory policy, with depots of different profiles requiring different policies. Understanding this systematic and systemic approach of fleet management, we assess the contribution of tracking technology capabilities to these potential improvements.by Jean-Marie Lefebvre and Dameng Yue.M.Eng.in Logistic

    Methane adsorption constrained by pore structure in high rank coals using FESEM, CO2 adsorption and NMRC techniques

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    This research was funded by the National Natural Science Fund (grant nos. 41830427, 41772160 and 41602170), the National Major Research Program for Science and Technology of China (grant no. 2016ZX05043-001), Key Research and Development Projects of The Xinjiang Uygur Autonomous Region (grant no. 2017B03019-01) and the Fundamental Research Funds for Central Universities (grant no. 2652018002).Peer reviewedPublisher PD

    Review on Applications of X-ray computed tomography for coal characterization : recent progress and perspectives

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    This research was funded by the National Natural Science Foundation of China (grant nos. 42130806, 41830427, 41922016 and 42102227).Peer reviewedPostprin

    Novel discrete fracture networks model for multiphase flow in coal

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    Acknowledgments This research was funded by the National Natural Science Foundation of China (Grants 41830427, 41922016, and 42130806) and the China Scholarship Council (202006400048).Peer reviewedPostprin

    Investigations of CO2-water wettability of coal : NMR relaxation method

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    Acknowledgments We acknowledge financial support from the National Natural Science Foundation of China (41472137), the Key Research and Development Projects of The Xinjiang Uygur Autonomous Region (2017B03019-01), and the National Major Research Program for Science and Technology of China (2016ZX05043-001), and the Royal Society Edinburgh and National Natural Science Foundation China (NSFC 41711530129).Peer reviewedPostprin

    Investigation on the methane adsorption capacity in coals : considerations from nanopores by multifractal analysis

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    ACKNOWLEDGEMENTS This research was funded by the National Natural Science Foundation of China (grant numbers 41830427, 41922016, and 41772160).Peer reviewedPostprin

    Size Distribution and Fractal Characteristics of Coal Pores through Nuclear Magnetic Resonance Cryoporometry

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    This research was funded by the National Natural Science Foundation of China (Grant no. 41602170), the Research Program for Excellent Doctoral Dissertation Supervisor of Beijing (grant no. YB20101141501), the Key Project of Coal-based Science and Technology in Shanxi Province-CBM accumulation model and reservoir evaluation in Shanxi province (grant no. MQ2014-01) and the Fundamental Research Funds for Central Universities (grant no. 35832015136).Peer reviewedPostprin
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