42 research outputs found

    Electrospray Deposition of PEDOT:PSS on Carbon Yarn Electrodes for Solid-State Flexible Supercapacitors

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    Funding Information: This work was financed by national funds from FCT─Fundação para a Ciência e a Tecnologia, I.P., in the scope of the All-FIBRE project with the reference PTDC/CTM-CTM/1571/2020, and the projects LA/P/0037/2020, UIDP/50025/2020, and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures, Nanomodelling, and Nanofabrication─i3N. This work was also supported by ERC-CoG-2014, CapTherPV, 647596. The authors would like to thank Professor Daniela Gomes from CENIMAT for the SEM images. Publisher Copyright: © 2023 The Authors. Published by American Chemical Society.The increasing demand for flexible electronic devices has risen due to the high interest in electronic textiles (e-textiles). Consequently, the urge to power e-textiles has sparked enormous interest in flexible energy storage devices. One-dimensional (1D) configuration supercapacitors are the most promising technology for textile applications, but often their production involves complex synthesis techniques and expensive materials. This work unveils the use of the novel electrospray deposition (ESD) technique for the deposition of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS). This deposition methodology on conductive carbon yarns creates flexible electrodes with a high surface area. The deposition conditions of PEDOT:PSS were optimized, and their influence on the electrochemical performance of a 1D symmetric supercapacitor with a cellulose-based gel as an electrolyte and a separator was evaluated. The tests herein reported show that these capacitors exhibited a high specific capacitance of 72 mF g-1, an excellent cyclability of more than 85% capacitance retention after 1500 cycles, and an outstanding capability of bending.publishersversionpublishe

    Volume I. Introduction to DUNE

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    The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay—these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. This TDR is intended to justify the technical choices for the far detector that flow down from the high-level physics goals through requirements at all levels of the Project. Volume I contains an executive summary that introduces the DUNE science program, the far detector and the strategy for its modular designs, and the organization and management of the Project. The remainder of Volume I provides more detail on the science program that drives the choice of detector technologies and on the technologies themselves. It also introduces the designs for the DUNE near detector and the DUNE computing model, for which DUNE is planning design reports. Volume II of this TDR describes DUNE\u27s physics program in detail. Volume III describes the technical coordination required for the far detector design, construction, installation, and integration, and its organizational structure. Volume IV describes the single-phase far detector technology. A planned Volume V will describe the dual-phase technology

    Deep Underground Neutrino Experiment (DUNE), far detector technical design report, volume III: DUNE far detector technical coordination

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    The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay—these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. Volume III of this TDR describes how the activities required to design, construct, fabricate, install, and commission the DUNE far detector modules are organized and managed. This volume details the organizational structures that will carry out and/or oversee the planned far detector activities safely, successfully, on time, and on budget. It presents overviews of the facilities, supporting infrastructure, and detectors for context, and it outlines the project-related functions and methodologies used by the DUNE technical coordination organization, focusing on the areas of integration engineering, technical reviews, quality assurance and control, and safety oversight. Because of its more advanced stage of development, functional examples presented in this volume focus primarily on the single-phase (SP) detector module

    Highly-parallelized simulation of a pixelated LArTPC on a GPU

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    The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype

    The DUNE far detector vertical drift technology. Technical design report

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    DUNE is an international experiment dedicated to addressing some of the questions at the forefront of particle physics and astrophysics, including the mystifying preponderance of matter over antimatter in the early universe. The dual-site experiment will employ an intense neutrino beam focused on a near and a far detector as it aims to determine the neutrino mass hierarchy and to make high-precision measurements of the PMNS matrix parameters, including the CP-violating phase. It will also stand ready to observe supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector implements liquid argon time-projection chamber (LArTPC) technology, and combines the many tens-of-kiloton fiducial mass necessary for rare event searches with the sub-centimeter spatial resolution required to image those events with high precision. The addition of a photon detection system enhances physics capabilities for all DUNE physics drivers and opens prospects for further physics explorations. Given its size, the far detector will be implemented as a set of modules, with LArTPC designs that differ from one another as newer technologies arise. In the vertical drift LArTPC design, a horizontal cathode bisects the detector, creating two stacked drift volumes in which ionization charges drift towards anodes at either the top or bottom. The anodes are composed of perforated PCB layers with conductive strips, enabling reconstruction in 3D. Light-trap-style photon detection modules are placed both on the cryostat's side walls and on the central cathode where they are optically powered. This Technical Design Report describes in detail the technical implementations of each subsystem of this LArTPC that, together with the other far detector modules and the near detector, will enable DUNE to achieve its physics goals

    A mathematical model to assess the influence of transients on a refractory-lined solar receiver

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    Available online 19 November 2020An approach to analyze and optimize the thermal performance of a refractory-lined particle receiver in response to solar resource variability has been demonstrated. A transient mathematical model has been developed, incorporating variable direct normal irradiance (DNI) and heat losses associated with a directly irradiated particle receiver. The model is employed to assess the time-dependent temperature fields of the receiver cavity walls, the particles and gas from the initial state to another equilibrium. The influence of the receiver's geometric parameters on the transient thermal response of the receiver has been assessed using real-time solar irradiance data based on the temperature changes for each phase. This can be used to support optimization of the refractory lining and insulation, to trade-off between the solar DNI input, thermal losses from the receiver, and allowable temperatures and heating rates of refractory and outer steel shell, via an energy balance. New insight is provided on the role of the material and thickness of the refractory lining on the system output when accounting for the allowable heating rate of refractory material to avoid failure due to thermal shock.Muhammad M. Rafique, Graham Nathan, Woei Sa

    On the Use of GPUs in Realizing Cost-Effective Distributed RAID

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    On the next generation bandwidth variable transponders for future flexible optical systems

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    Elastic optical networks represent one of the most promising candidates for the imminent upgrade of current fixed-grid based optical systems. This novel architecture based on high efficient spectrum allocation (i.e. higher capacity), is necessary to cope with foreseen future exponential increase of Internet traffic. This work discusses the influence of hardware components on the transmission performance of recently proposed bandwidth variable transponders employing digital signal processing algorithms. Both are key elements for the realization of future elastic optical networks, and only their successful interplay with coherent detection can enable the transmission of different modulation formats at variable symbol and data-rates over flexible links. We evaluate the performance of such transponders when different modulation schemes are generated employing ideal and realistic values for some key hardware components. Finally, we briefly present a couple of examples of mitigation techniques: namely digital pre-distortion and digital back-propagation

    Analysis of Task Offloading for Accelerators

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    Abstract. As an answer to the forthcoming heterogeneous multicore and accelerator–based architectures, we have proposed some syntactic extensions to C in the form of C pragmas, based on OpenMP, that make easier for programmers to offload parts of their applications to the auxiliary processors. Offloaded tasks can be made more profitable using a simple blocking strategy. And the runtime system is used to better support computation and communication overlap, while moving data to and from accelerators. In order to prove the feasibility and usefulness of our proposal, we have considered the IBM Cell architecture. The performance of the whole system has been evaluated using HPCC STREAM Triad and several NAS benchmarks. We present their evaluation and a detailed performance breakdown at the level of parallel regions. We also classify the parallel regions according to their suitability to be exploited in accelerators. Overall, our performance is better compared to the results obtained from the IBM compiler for the Cell processor.
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