| 1. |
- Müser, M. H., et al.
(författare)
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Meeting the Contact-Mechanics Challenge
- 2017
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Ingår i: Tribology letters. - : Springer New York LLC. - 1023-8883 .- 1573-2711. ; 65:4
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Tidskriftsartikel (refereegranskat)abstract
- This paper summarizes the submissions to a recently announced contact-mechanics modeling challenge. The task was to solve a typical, albeit mathematically fully defined problem on the adhesion between nominally flat surfaces. The surface topography of the rough, rigid substrate, the elastic properties of the indenter, as well as the short-range adhesion between indenter and substrate, were specified so that diverse quantities of interest, e.g., the distribution of interfacial stresses at a given load or the mean gap as a function of load, could be computed and compared to a reference solution. Many different solution strategies were pursued, ranging from traditional asperity-based models via Persson theory and brute-force computational approaches, to real-laboratory experiments and all-atom molecular dynamics simulations of a model, in which the original assignment was scaled down to the atomistic scale. While each submission contained satisfying answers for at least a subset of the posed questions, efficiency, versatility, and accuracy differed between methods, the more precise methods being, in general, computationally more complex. The aim of this paper is to provide both theorists and experimentalists with benchmarks to decide which method is the most appropriate for a particular application and to gauge the errors associated with each one..
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| 2. |
- Wu, Yaoxing, et al.
(författare)
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A reference method for measuring emissions of SVOCs in small chambers
- 2016
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Ingår i: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 95, s. 126-132
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Tidskriftsartikel (refereegranskat)abstract
- Semi-volatile organic compounds (SVOCs) are indoor air pollutants that may have significant adverse effects on human health. Although emissions of volatile chemicals from building materials and consumer products are usually characterized in small chambers, few chamber studies have been conducted for SVOCs due to the challenges associated with analysis and the lack of validation procedures. There is an urgent need for a reliable and accurate chamber test method to verify these measurements. A reference method employing a specially-designed chamber has been developed and is undergoing extensive evaluation. A pilot inter-laboratory study (ILS) has been conducted with six laboratories performing chamber tests under identical conditions for di-2-ethylhexyl phthalate (DEHP). Results from this study showed inter-laboratory variations of 24% for DEHP emission rates, with closer agreement observed among intra-laboratory measurements for most of the participating laboratories. A mechanistic emission model fits well to the measured concentration profiles, demonstrating the feasibility of the proposed reference method to independently assess laboratory performance and validate SVOC emission tests.
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| 3. |
- Zhang, L., et al.
(författare)
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Quantum Noise Secured Terahertz Communications
- 2023
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - : Institute of Electrical and Electronics Engineers Inc.. - 1077-260X .- 1558-4542. ; 29:5
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Tidskriftsartikel (refereegranskat)abstract
- The terahertz communications display an important role in high-speed wireless communications, the security threat from the eavesdroppers in the terahertz communications has been gaining attention recently. The true randomness in the physical layer can ensure one-time-pad encryption for secured terahertz communications, however, physical layer security schemes like the quantum key distribution methods suffer from device imperfections that limit the desirable signal rate and link distance. Herein, we present the quantum noise secured terahertz wireless communications with photonic terahertz signal generation schemes. With the high-order diffusion algorithms, the signal is masked by the quantum noise ciphers to the eavesdroppers and cannot be detected because the inevitable randomness by quantum noise measurement will cause physical measurement errors. In the experiment, we demonstrate 16 Gbits-1 quantum noise secured terahertz wireless communications with the conventional optical communication realms and devices, operating at 300 GHz terahertz frequency. This quantum noise secured terahertz communication approach is a significant step toward high-security wireless communications.
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| 4. |
- Zhou, R., et al.
(författare)
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Maritime Disruption Impact Evaluation Using Simulation and Big Data Analytics
- 2022
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Ingår i: Proceedings - Winter Simulation Conference. - : Institute of Electrical and Electronics Engineers Inc.. - 9798350309713 ; , s. 784-795
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Konferensbidrag (refereegranskat)abstract
- Disruptions in maritime networks may cause significant financial burden and damage to business. Recently, some international ports have been experiencing unprecedented congestions due to the COVID19 pandemic and other disruptions. It is paramount for the maritime industry to further enhance the capability to assess and predict impacts of disruptions. With more data available from industrial digitization and more advanced technologies developed for big data analytics and simulation, it is possible to build up such capability. In this study, we developed a discrete event simulation model backed with big data analytics for realistic and valid inputs to assess impacts of the Suez Canal blockage to the Port of Singapore. The simulation results reveal an interesting finding that, the blockage occurred in the Suez Canal can hardly cause significant congestion in the Port of Singapore. The work can be extended to evaluate impacts of other types of disruptions, even occurring concurrently.
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| 5. |
- Zhu, G., et al.
(författare)
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Synergistic reduction on PM and NO source emissions during preheating-combustion of pulverized coal
- 2024
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Ingår i: Fuel. - : Elsevier Ltd. - 0016-2361 .- 1873-7153. ; 361
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Tidskriftsartikel (refereegranskat)abstract
- The present research focuses on the synergistic source control of particulate matter (PM) and NOx formation from pulverized coal combustion. Comparative experiments of preheating-combustion and conventional combustion were conducted in a lab-scale high-temperature preheating-combustion furnace, and PM10 and NO were measured by an electrical low pressure impactor and a flue gas analyzer, respectively. The results of the experiment indicate that preheating-combustion has a significant reduction in PM10 (especially PM0.3 up to 37.51 %) and NO, which can achieve the synergistic control of PM10 and NO source emissions during the combustion process. The fragmentation in preheating-combustion was weaker compared to the conventional combustion. Meanwhile, the relatively weak preheating-combustion coal char oxidation reaction leads to a decrease in ultrafine mode PM yielded due to the inhibition on vaporization of mineral inclusions. The PM0.3/PM1 mass ratio of the preheating-combustion has a decreasing trend, implying an elevated yield of PM0.3-1 and a shift of the average PM1 particle size toward a larger particle size. Higher preheating temperature (Tp) presented the potential to further reduce NO formation, and the NO reduction efficiency increased from 46.59 % to 56.60 % when the Tp was increased from 1200 K to 1600 K. All our preliminary results throw light on the nature of synergistic source control of preheating-combustion PM and NO formation.
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