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Influences of microparticle radius and microchannel height on SSAW-based acoustophoretic aggregation
No full textThe use of acoustic waves for microfluidic aggregation has become widespread in chemistry, biology and medicine. Although numerous experimental and analytical studies have been undertaken to study the acoustophoretic aggregation mechanisms, few studies have been conducted to optimise the device design. This paper presents a numerical investigation of the acoustophoresis of microparticles suspended in compressible liquid. The wall of the rectangular microchannel is made of Polydimethylsiloxane (PDMS), and Standing Surface Acoustic Waves (SSAW) are introduced into the channel from the bottom wall. First, the relative amplitude of the acoustic radiation force and the viscous drag force is evaluated for particles of different radii ranging from 0.1μm to 15μm. Only when the particle size is larger than a critical value can the particles accumulate at acoustic pressure nodes (PNs). The efficiency of the particle accumulation depends on the microchannel height, so an extensive parametric study is then undertaken to identify the optimum microchannel height. The optimum height, when normalised by the acoustic wavelength, is found to be between 0.57 and 0.82. These findings provide insights into the design of acoustophoretic devices
HTS Flux Pump Charging an HTS Coil: Experiment and Modeling
No full textAn HTS flux pump is an effective device to compensate the field decay in HTS magnets running in persistent mode. This paper contains updates to the model for the travelling wave HTS electromagnetic flux pump, in which the magnetization system is modelled as an L-R circuit. In this paper we consider the various sources of resistance. There are three components, joint resistance, resistance of superconductor and dynamic resistance. Joint resistance is treated as a constant. The superconducting resistance is derived from the E-J model and finally the dynamic resistance is a function of applied field strength and frequency. In addition the model includes the electromotive force which is a function of the applied field, frequency and surface area of the tape. This is a calculated value based on the φ model we built. In order to test the model, a series of experiments were performed in which an HTS coil was actuated using our flux pump. The flux pump test rig was made from 4-pair rectangular copper solenoids with laminated iron cores, which were fixed on the supporting iron frame. This rig was used to magnetize a double layer HTS racetrack coil at 77 K. The induced current in superconducting coil can reach more than 90% of critical current. Our model was found to be a good fit to the experimental data
Development of a moving point source model for shipping emission dispersion modeling in EPISODE-CityChem v1.3
No full textThis paper demonstrates the development of a moving point source (MPS) model for simulating the atmospheric dispersion of pollutants emitted from ships under movement. The new model is integrated into the chemistry transport model EPISODE-CityChem v1.3. In the new model, ship parameters, especially speed and direction, are included to simulate the instantaneous ship positions and then the emission dispersion at different simulation time. The model was first applied to shipping emission dispersion modeling under simplified conditions, and the instantaneous and hourly averaged emission concentrations predicted by the MPS model and the commonly used line source (LS) and fixed point source (FPS) models were compared. The instantaneous calculations were quite different due to the different ways to treat the moving emission sources by different models. However, for the hourly averaged concentrations, the differences became smaller, especially for a large number of ships. The new model was applied to a real configuration from the seas around Singapore that included hundreds of ships, and their dispersion was simulated over a period of a few hours. The simulated results were compared to measured values at different locations, and it was found that reasonable emission concentrations were predicted by the moving point source model
A Feasible Strategy for Identifying Single-Atom Catalysts Toward Electrochemical NO-to-NH<inf>3</inf> Conversion
No full textCombining NO removal and NH3 synthesis, electrochemical NO reduction reaction (NORR) toward NH3 is considered as a novel and attractive approach. However, exploring suitable catalysts for NO-to-NH3 conversion is still a formidable task due to the lack of a feasible method. Herein, utilizing systematic first-principles calculations, a rational strategy for screening efficient single-atom catalysts (SACs) for NO-to-NH3 conversion is reported. This strategy runs the gamut of stability, NO adsorbability, NORR activity, and NH3 selectivity. Taking transition metal atom embedded in C2N (TM-C2N) as an example, its validity is demonstrated and Zr-C2N is selected as a stable NO-adsorbable NORR catalyst with high NH3 selectivity. Therefore, this work has established a theoretical landscape for screening SACs toward NO-to-NH3 conversion, which will contribute to the application of SACs for NORR and other electrochemical reactions
Energy transition pathways amongst low-income urban households: A mixed method clustering approach
No full textStudies on clean energy transition amongst low-income urban households in the Global South use an array of qualitative and quantitative methods. However, attempts to combine qualitative and quantitative methods are rare and there are a lack of systematic approaches to this. This paper demonstrates a two stage approach using clustering methods to analyse a mixed dataset containing quantitative household survey data and qualitative interview data. By clustering the quantitative and qualitative data separately, latent groups with common characteristics and narratives arising from each of the two analyses are identified. A second stage of clustering identifies links between these qualitative and quantitative clusters and enables inference of energy transition pathways followed by low-income urban households defined by both quantitative characteristics and qualitative narratives. This approach can support interdisciplinary collaboration in energy research, providing a systematic approach to comparing and identifying links between quantitative and qualitative findings
METTL1-mediated m7G modification of Arg-TCT tRNA drives oncogenic transformation.
No full textThe emerging "epitranscriptomics" field is providing insights into the biological and pathological roles of different RNA modifications. The RNA methyltransferase METTL1 catalyzes N7-methylguanosine (m7G) modification of tRNAs. Here we find METTL1 is frequently amplified and overexpressed in cancers and is associated with poor patient survival. METTL1 depletion causes decreased abundance of m7G-modified tRNAs and altered cell cycle and inhibits oncogenicity. Conversely, METTL1 overexpression induces oncogenic cell transformation and cancer. Mechanistically, we find increased abundance of m7G-modified tRNAs, in particular Arg-TCT-4-1, and increased translation of mRNAs, including cell cycle regulators that are enriched in the corresponding AGA codon. Accordingly, Arg-TCT expression is elevated in many tumor types and is associated with patient survival, and strikingly, overexpression of this individual tRNA induces oncogenic transformation. Thus, METTL1-mediated tRNA modification drives oncogenic transformation through a remodeling of the mRNA "translatome" to increase expression of growth-promoting proteins and represents a promising anti-cancer target
Saturated Iron-core Superconducting Fault Current Limiter for VSC Network: System Modeling with Loss Analysis
No full textThe potential application of the superconducting fault current limiter (SFCL) in a voltage source convert (VSC) system has received lots of attention. On the basis of the fault current limiting characteristics, this paper evaluated the loss level of saturated iron-core FCLs (SI-SFCLs) in a VSC-based distribution grid. The models of VSC network and the SI-SFCL model were respectively developed. Then, with and without the implementation of SI-SFCLs, the fault current process under positive-to-ground and positive-to-negative short-circuit was presented. Next, the power dissipated from the superconducting coil was curved. Analysis demonstrated the power dissipation of the SI-SFCL during the short-circuit is likely to reach tens of kilowatts. This study can provide a helpful guidance for the design of SI-SFCLs
Quantum Key Secured Communications Field Trial for Industry 4.0
No full textWe seamlessly integrate quantum key distribution with >1Mb/s secure bit rate into a smart-manufacturing production network. This provides a 10Gb/s quantum key encrypted link with long-term stable operation, compatible with national network infrastructure
Novel Scalable and Reconfigurable Optical Fronthaul Network for Converged Radio Frequency and Data Services Using Silicon Photonic Switching
No full textWe propose and demonstrate a converged optical fronthaul network for RF and data services with scalable silicon photonic switching. A 1.5dB power penalty at a 10-9 BER and over 40dB RF dynamic range are demonstrated
GeoBIM for built environment condition assessment supporting asset management decision making
No full textThe digital transformation in management of the built environment is more and more evident. While the benefits of location data, from Building Information Modelling or Geographical Information Systems, have been explored separately, their combination - GeoBIM - in asset management has never been explored. Data collection for condition assessment is challenging due to quantity, types, frequency and quality of data. We first describe the opportunities and challenges of GeoBIM for condition assessment. The theoretical approach is then validated developing an integrated GeoBIM model of the digital built environment, for a neighbourhood in Milan, Italy. Data are collected, linked, processed and analysed, through multiple software platforms, providing relevant information for asset management decision making. Good results are achieved in rapid massive data collection, improved visualisation, and analysis. While further testing and development is required, the case study outcomes demonstrated the innovation and the mid-term service-oriented potential of the proposed approach