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Showing papers by "National Physical Laboratory published in 2020"


Journal ArticleDOI
TL;DR: In this paper, the authors comprehensively discuss what is known about the different processes that govern the transport of floating marine plastic debris in both the open ocean and the coastal zones, based on the published literature and referring to insights from neighbouring fields such as oil spill dispersion, marine safety recovery, plankton connectivity, and others.
Abstract: Marine plastic debris floating on the ocean surface is a major environmental problem. However, its distribution in the ocean is poorly mapped, and most of the plastic waste estimated to have entered the ocean from land is unaccounted for. Better understanding of how plastic debris is transported from coastal and marine sources is crucial to quantify and close the global inventory of marine plastics, which in turn represents critical information for mitigation or policy strategies. At the same time, plastic is a unique tracer that provides an opportunity to learn more about the physics and dynamics of our ocean across multiple scales, from the Ekman convergence in basin-scale gyres to individual waves in the surfzone. In this review, we comprehensively discuss what is known about the different processes that govern the transport of floating marine plastic debris in both the open ocean and the coastal zones, based on the published literature and referring to insights from neighbouring fields such as oil spill dispersion, marine safety recovery, plankton connectivity, and others. We discuss how measurements of marine plastics (both in situ and in the laboratory), remote sensing, and numerical simulations can elucidate these processes and their interactions across spatio-temporal scales.

408 citations


Journal ArticleDOI
Yousef Abou El-Neaj1, Cristiano Alpigiani2, Sana Amairi-Pyka3, Henrique Araujo4, Antun Balaž5, Angelo Bassi6, Lars Bathe-Peters7, Baptiste Battelier8, Aleksandar Belić5, Elliot Bentine9, Jose Bernabeu10, Andrea Bertoldi8, Robert Bingham11, Robert Bingham12, Diego Blas13, Vasiliki Bolpasi14, Kai Bongs15, Sougato Bose16, Philippe Bouyer8, T. J. V. Bowcock17, William B. Bowden18, Oliver Buchmueller4, Clare Burrage19, Xavier Calmet20, Benjamin Canuel8, Laurentiu Ioan Caramete, Andrew Carroll17, Giancarlo Cella6, Vassilis Charmandaris14, S. Chattopadhyay21, S. Chattopadhyay22, Xuzong Chen23, Maria Luisa Chiofalo24, J. P. Coleman17, J. P. Cotter4, Y. Cui25, Andrei Derevianko26, Albert De Roeck27, Goran S. Djordjevic28, P. J. Dornan4, Michael Doser27, Ioannis Drougkakis14, Jacob Dunningham20, Ioana Dutan, Sajan Easo11, G. Elertas17, John Ellis13, John Ellis29, John Ellis27, Mai El Sawy30, Mai El Sawy31, Farida Fassi, D. Felea, Chen Hao Feng8, R. L. Flack16, Christopher J. Foot9, Ivette Fuentes19, Naceur Gaaloul32, A. Gauguet33, Remi Geiger34, Valerie Gibson35, Gian F. Giudice27, J. Goldwin15, O. A. Grachov36, Peter W. Graham37, Dario Grasso24, Maurits van der Grinten11, Mustafa Gündoğan3, Martin G. Haehnelt35, Tiffany Harte35, Aurélien Hees34, Richard Hobson18, Jason M. Hogan37, Bodil Holst38, Michael Holynski15, Mark A. Kasevich37, Bradley J. Kavanagh39, Wolf von Klitzing14, Tim Kovachy40, Benjamin Krikler41, Markus Krutzik3, Marek Lewicki13, Marek Lewicki42, Yu-Hung Lien16, Miaoyuan Liu23, Giuseppe Gaetano Luciano6, Alain Magnon43, Mohammed Mahmoud44, Sudhir Malik4, Christopher McCabe13, J. W. Mitchell21, Julia Pahl3, Debapriya Pal14, Saurabh Pandey14, Dimitris G. Papazoglou45, Mauro Paternostro46, Bjoern Penning47, Achim Peters3, Marco Prevedelli48, Vishnupriya Puthiya-Veettil49, J. J. Quenby4, Ernst M. Rasel32, Sean Ravenhall9, Jack Ringwood17, Albert Roura50, D. O. Sabulsky8, M. Sameed51, Ben Sauer4, Stefan A. Schäffer52, Stephan Schiller53, Vladimir Schkolnik3, Dennis Schlippert32, Christian Schubert32, Haifa Rejeb Sfar, Armin Shayeghi54, Ian Shipsey9, Carla Signorini24, Yeshpal Singh15, Marcelle Soares-Santos47, Fiodor Sorrentino6, T. J. Sumner4, Konstantinos Tassis14, S. Tentindo55, Guglielmo M. Tino56, Guglielmo M. Tino6, Jonathan N. Tinsley56, James Unwin57, Tristan Valenzuela11, Georgios Vasilakis14, Ville Vaskonen29, Ville Vaskonen13, Christian Vogt58, Alex Webber-Date17, André Wenzlawski59, Patrick Windpassinger59, Marian Woltmann58, Efe Yazgan60, Ming Sheng Zhan60, Xinhao Zou8, Jure Zupan61 
Harvard University1, University of Washington2, Humboldt University of Berlin3, Imperial College London4, University of Belgrade5, Istituto Nazionale di Fisica Nucleare6, Technical University of Berlin7, University of Bordeaux8, University of Oxford9, University of Valencia10, Rutherford Appleton Laboratory11, University of Strathclyde12, King's College London13, Foundation for Research & Technology – Hellas14, University of Birmingham15, University College London16, University of Liverpool17, National Physical Laboratory18, University of Nottingham19, University of Sussex20, Northern Illinois University21, Fermilab22, Peking University23, University of Pisa24, University of California, Riverside25, University of Nevada, Reno26, CERN27, University of Niš28, National Institute of Chemical Physics and Biophysics29, British University in Egypt30, Beni-Suef University31, Leibniz University of Hanover32, Paul Sabatier University33, University of Paris34, University of Cambridge35, Wayne State University36, Stanford University37, University of Bergen38, University of Amsterdam39, Northwestern University40, University of Bristol41, University of Warsaw42, University of Illinois at Urbana–Champaign43, Fayoum University44, University of Crete45, Queen's University Belfast46, Brandeis University47, University of Bologna48, Cochin University of Science and Technology49, German Aerospace Center50, University of Manchester51, University of Copenhagen52, University of Düsseldorf53, University of Vienna54, Florida State University55, University of Florence56, University of Illinois at Chicago57, University of Bremen58, University of Mainz59, Chinese Academy of Sciences60, University of Cincinnati61
TL;DR: The Atomic Experiment for Dark Matter and Gravity Exploration (AEDGE) as mentioned in this paper is a space experiment using cold atoms to search for ultra-light dark matter, and to detect gravitational waves in the frequency range between the most sensitive ranges of LISA and the terrestrial LIGO/Virgo/KAGRA/INDIGO experiments.
Abstract: We propose in this White Paper a concept for a space experiment using cold atoms to search for ultra-light dark matter, and to detect gravitational waves in the frequency range between the most sensitive ranges of LISA and the terrestrial LIGO/Virgo/KAGRA/INDIGO experiments. This interdisciplinary experiment, called Atomic Experiment for Dark Matter and Gravity Exploration (AEDGE), will also complement other planned searches for dark matter, and exploit synergies with other gravitational wave detectors. We give examples of the extended range of sensitivity to ultra-light dark matter offered by AEDGE, and how its gravitational-wave measurements could explore the assembly of super-massive black holes, first-order phase transitions in the early universe and cosmic strings. AEDGE will be based upon technologies now being developed for terrestrial experiments using cold atoms, and will benefit from the space experience obtained with, e.g., LISA and cold atom experiments in microgravity.

259 citations


Journal ArticleDOI
TL;DR: In this article, a focus review summarising best metrological practice in the application of EIS to commercial Li-ion cells is presented, highlighting the benefits and drawbacks of the technique.

259 citations


Journal ArticleDOI
TL;DR: AION (Atom Interferometer Observatory and Network) as mentioned in this paper is a proposed UK-based experimental program using cold strontium atoms to search for ultra-light dark matter, to explore gravitational waves in the mid-frequency range between the peak sensitivities of the LISA and LIGO/Virgo/ KAGRA/INDIGO-Einstein Telescope/Cosmic Explorer experiments, and to probe other frontiers in fundamental physics.
Abstract: We outline the experimental concept and key scientific capabilities of AION (Atom Interferometer Observatory and Network), a proposed UK-based experimental programme using cold strontium atoms to search for ultra-light dark matter, to explore gravitational waves in the mid-frequency range between the peak sensitivities of the LISA and LIGO/Virgo/ KAGRA/INDIGO/Einstein Telescope/Cosmic Explorer experiments, and to probe other frontiers in fundamental physics. AION would complement other planned searches for dark matter, as well as probe mergers involving intermediate mass black holes and explore early universe cosmology. AION would share many technical features with the MAGIS experimental programme in the US, and synergies would flow from operating AION in a network with this experiment, as well as with other atom interferometer experiments such as MIGA, ZAIGA and ELGAR. Operating AION in a network with other gravitational wave detectors such as LIGO, Virgo and LISA would also offer many synergies.

256 citations


Journal ArticleDOI
TL;DR: The essential differences between a model and a digital twin are highlighted, some of the key benefits of using digital twins are outlined, and directions for further research are suggested to fully exploit the potential of the approach.
Abstract: “When I use a word, it means whatever I want it to mean”: Humpty Dumpty in Alice’s Adventures Through The Looking Glass, Lewis Carroll. “Digital twin” is currently a term applied in a wide variety of ways. Some differences are variations from sector to sector, but definitions within a sector can also vary significantly. Within engineering, claims are made regarding the benefits of using digital twinning for design, optimisation, process control, virtual testing, predictive maintenance, and lifetime estimation. In many of its usages, the distinction between a model and a digital twin is not made clear. The danger of this variety and vagueness is that a poor or inconsistent definition and explanation of a digital twin may lead people to reject it as just hype, so that once the hype and the inevitable backlash are over the final level of interest and use (the “plateau of productivity”) may fall well below the maximum potential of the technology. The basic components of a digital twin (essentially a model and some data) are generally comparatively mature and well-understood. Many of the aspects of using data in models are similarly well-understood, from long experience in model validation and verification and from development of boundary, initial and loading conditions from measured values. However, many interesting open questions exist, some connected with the volume and speed of data, some connected with reliability and uncertainty, and some to do with dynamic model updating. In this paper we highlight the essential differences between a model and a digital twin, outline some of the key benefits of using digital twins, and suggest directions for further research to fully exploit the potential of the approach.

236 citations


Journal ArticleDOI
TL;DR: It is shown that the microstructural heterogeneities lead to non-uniform Li insertion and current distribution while graded-microstructures improve the performance.
Abstract: Driving range and fast charge capability of electric vehicles are heavily dependent on the 3D microstructure of lithium-ion batteries (LiBs) and substantial fundamental research is required to optimise electrode design for specific operating conditions. Here we have developed a full microstructure-resolved 3D model using a novel X-ray nano-computed tomography (CT) dual-scan superimposition technique that captures features of the carbon-binder domain. This elucidates how LiB performance is markedly affected by microstructural heterogeneities, particularly under high rate conditions. The elongated shape and wide size distribution of the active particles not only affect the lithium-ion transport but also lead to a heterogeneous current distribution and non-uniform lithiation between particles and along the through-thickness direction. Building on these insights, we propose and compare potential graded-microstructure designs for next-generation battery electrodes. To guide manufacturing of electrode architectures, in-situ X-ray CT is shown to reliably reveal the porosity and tortuosity changes with incremental calendering steps.

223 citations


Journal ArticleDOI
TL;DR: The use of the Butler-Volmer equation to describe electrode kinetics has been extensively studied in the literature, such as misuse of terminology or inappropriate mathematical expressions of the kinetic equations as mentioned in this paper.

108 citations


Journal ArticleDOI
TL;DR: In this article, the authors proposed a method to transform X-ray photoelectron spectroscopy (XPS) data into meaningful information on the concentration and distribution of chemical species.
Abstract: X-ray photoelectron spectroscopy (XPS) is widely used to identify chemical species at a surface through the observation of peak positions and peak shapes. It is less widely recognized that intensities in XPS spectra can also be used to obtain information on the chemical composition of the surface of the sample and the depth distribution of chemical species. Transforming XPS data into meaningful information on the concentration and distribution of chemical species is the topic of this article. In principle, the process is straightforward, but there are a number of pitfalls that must be avoided to ensure that the information is representative and as accurate as possible. This paper sets out the things that should be considered to obtain reliable, meaningful, and useful information from quantitative XPS. This includes the necessity for reference data, instrument performance checks, and a consistent and methodical method for the separation of inelastic background from peaks. The paper contains relevant and simple equations along with guidance on their use, validity, and assumptions.

94 citations


Journal ArticleDOI
TL;DR: It is proved that the worst-case complexity of the basic chirp reconstruction algorithm is ${\mathscr{O}}[nK(\log _2^2 n + K)], which makes the reconstruction computationally feasible—a claim supported by reporting computing times for the algorithm.
Abstract: Unsourced multiple access abstracts grantless simultaneous communication of a large number of devices (messages) each of which transmits (is transmitted) infrequently. It provides a model for machine-to-machine communication in the Internet of Things (IoT), including the special case of radio-frequency identification (RFID), as well as neighbor discovery in ad hoc wireless networks. This paper presents a fast algorithm for unsourced multiple access that scales to $2^{100}$ devices (arbitrary $100$ bit messages). The primary building block is multiuser detection of binary chirps which are simply codewords in the second order Reed Muller code. The chirp detection algorithm originally presented by Howard et al. is enhanced and integrated into a peeling decoder designed for a patching and slotting framework. In terms of both energy per bit and number of transmitted messages, the proposed algorithm is within a factor of $2$ of state of the art approaches. A significant advantage of our algorithm is its computational efficiency. We prove that the worst-case complexity of the basic chirp reconstruction algorithm is $\mathcal{O}[nK(\log_2 n + K)]$, where $n$ is the codeword length and $K$ is the number of active users, and we report computing times for our algorithm. Our performance and computing time results represent a benchmark against which other practical algorithms can be measured.

83 citations


Journal ArticleDOI
16 Dec 2020-Joule
TL;DR: In this paper, the authors conduct an in situ calendering experiment on lithium-ion battery cathodes using X-ray nano-computed tomography, and show that the electrodes composed of large particles with a broad size distribution experience heterogeneous microstructural self-arrangement.

77 citations


Journal ArticleDOI
01 Jul 2020
TL;DR: In this article, the frontiers of graphene-based sensors considering both electrical and optical methods of detection and discuss the topical progress in an attempt to establish whether graphene can be considered as the ideal sensing material.
Abstract: The World Health Organization reported that 4.2 million deaths every year were a direct result of exposure to ambient air pollution (NO2, SO2, NH3, CO2, CO). There is a well-demonstrated global need for high sensitivity, low cost and low energy consumption miniaturised gas sensors to be deployed in a dense network and to be used in an attempt to pinpoint and avoid high pollution hot spots. The high sensitivity of graphene to the local environment has shown to be highly advantageous in sensing applications, where ultralow concentrations of adsorbed molecules induce a significant response on the electronic properties of graphene. This is commonly attributed to the π electrons of graphene, being directly exposed to the surrounding environment. The unique electronic structure makes graphene the "ultimate" sensing material for applications in environmental monitoring and air quality. In this review, we present the frontiers of graphene-based sensors considering both electrical and optical methods of detection and discuss the topical progress in an attempt to establish whether graphene can be considered as the ideal sensing material. We pay special attention to the optimization of the sensor performance, using various graphene hybrids and doping mechanisms. Furthermore, we present the recent developments in other 2D material-based sensors that have followed in the wake of graphene. We discuss the benchmarked parameters of graphene sensors, such as sensitivity, selectivity, response/recovery time and detection limit, and compare them with other 2D materials as well as existing state-of-the-art sensors currently being used in the field. We also perform a brief market analyses for the environmental sensing industry as well as provide a Strengths – Weaknesses – Opportunities – Threats analysis of graphene technology for environmental sensing.

Journal ArticleDOI
TL;DR: This review investigates the specifications that are typically being used in development of the latest TMMs and investigates the imaging modalities that have been investigated focus around CT, mammography, SPECT, PET, MRI and ultrasound.
Abstract: Tissue mimicking materials (TMMs), typically contained within phantoms, have been used for many decades in both imaging and therapeutic applications. This review investigates the specifications that are typically being used in development of the latest TMMs. The imaging modalities that have been investigated focus around CT, mammography, SPECT, PET, MRI and ultrasound. Therapeutic applications discussed within the review include radiotherapy, thermal therapy and surgical applications. A number of modalities were not reviewed including optical spectroscopy, optical imaging and planar x-rays. The emergence of image guided interventions and multimodality imaging have placed an increasing demand on the number of specifications on the latest TMMs. Material specification standards are available in some imaging areas such as ultrasound. It is recommended that this should be replicated for other imaging and therapeutic modalities. Materials used within phantoms have been reviewed for a series of imaging and therapeutic applications with the potential to become a testbed for cross-fertilization of materials across modalities. Deformation, texture, multimodality imaging and perfusion are common themes that are currently under development.

Journal ArticleDOI
TL;DR: An overview of the current state of developments of radiotherapy with FLASH electrons and protons, very high energy electrons as well as laser-driven particles and the related challenges in dosimetry due to the ultra-high dose rate during the short radiation pulses is given.

Journal ArticleDOI
TL;DR: In this article, the authors search for coherent variations in the recorded clock frequency comparisons across the network, and significantly improve the constraints on transient variations of the fine structure constant, for example, constraining the variation to |δα/α| ~10^4 km.
Abstract: We search for transient variations of the fine structure constant using data from a European network of fiber-linked optical atomic clocks. By searching for coherent variations in the recorded clock frequency comparisons across the network, we significantly improve the constraints on transient variations of the fine structure constant. For example, we constrain the variation to |δα/α| ~10^4 km) objects.

Journal ArticleDOI
14 Jan 2020
TL;DR: In this article, the wear mechanism of diamond tools, and the typical wear reduction methods for diamond cutting of ferrous metals, including ultrasonic vibration cutting, cryogenic cutting, surface nitridation and plasma assisted cutting, etc.
Abstract: Diamond tools play a critical role in ultra-precision machining due to their excellent physical and mechanical material properties, such as that cutting edge can be sharpened to nanoscale accuracy. However, abrasive chemical reactions between diamond and non-diamond-machinable metal elements, including Fe, Cr, Ti, Ni, etc, can cause excessive tool wear in diamond cutting of such metals and most of their alloys. This paper reviews the latest achievements in the chemical wear and wear suppression methods for diamond tools in cutting of ferrous metals. The focus will be on the wear mechanism of diamond tools, and the typical wear reduction methods for diamond cutting of ferrous metals, including ultrasonic vibration cutting, cryogenic cutting, surface nitridation and plasma assisted cutting, etc. Relevant commercially available devices are introduced as well. Furthermore, future research trends in diamond tool wear suppression are discussed and examined.

Journal ArticleDOI
TL;DR: The overall aim of this framework and scoring system is to improve the scientific quality of treatment planning studies and papers, and it might also be used by reviewers and journal editors to help to evaluate scientific manuscripts reporting planning studies.

Journal ArticleDOI
TL;DR: Here, a previously unexplored decoherence mechanism is revealed in the form of a new type of TLS originating from trapped QPs, which can induce qubit relaxation and thus affect coherence over exponentially long time scales.
Abstract: A major issue for the implementation of large-scale superconducting quantum circuits is the interaction with interfacial two-level system (TLS) defects that lead to qubit parameter fluctuations and relaxation. Another major challenge comes from nonequilibrium quasiparticles (QPs) that result in qubit relaxation and dephasing. Here, we reveal a previously unexplored decoherence mechanism in the form of a new type of TLS originating from trapped QPs, which can induce qubit relaxation. Using spectral, temporal, thermal, and magnetic field mapping of TLS-induced fluctuations in frequency tunable resonators, we identify a highly coherent subset of the general TLS population with a low reconfiguration temperature ∼300 mK and a nonuniform density of states. These properties can be understood if the TLS are formed by QPs trapped in shallow subgap states formed by spatial fluctutations of the superconducting order parameter. This implies that even very rare QP bursts will affect coherence over exponentially long time scales.

Journal ArticleDOI
TL;DR: This review should be valuable for deeply understanding the materials fabrication principles, device designs, cell penetration methodologies, biosafety aspects, and application strategies of nanoneedle array‐based systems that are of crucial importance for the development of future practical biomedical platforms.
Abstract: Establishing techniques to efficiently and nondestructively access the intracellular milieu is essential for many biomedical and scientific applications, ranging from drug delivery, to electrical recording, to biochemical detection. Cell penetration using nanoneedle arrays is currently a research focus area because it not only meets the increasing therapeutic demands of cell modifications and genome editing, but also provides an ideal platform for tracking long‐term intracellular information. Although the precise mechanism driving membrane penetration by nanoneedle arrays is still unclear, the low cytotoxicity, wide range of delivered materials, diverse cell type targets, and simple material structures of nanoneedle arrays make these splendid platforms for cell access. Here, the recent progress in this field is reviewed by examining device architectures and discussing mechanisms for nanoneedle penetration, and the major studies demonstrating the most general applicability of nanoneedle arrays, typical methodologies to access the intracellular environment using nanoneedles with spontaneous or assisted penetration modes, as well as biosafety aspects are presented. This review should be valuable for deeply understanding the materials fabrication principles, device designs, cell penetration methodologies, biosafety aspects, and application strategies of nanoneedle array‐based systems that are of crucial importance for the development of future practical biomedical platforms.

Journal ArticleDOI
TL;DR: Graphite calorimetry, the UK primary standard, has been employed to measure the dose delivered from a 200 MeV pulsed electron beam and was compared to the charge measurements of a plane-parallel ionisation chamber to determine the absolute collection efficiency and infer the ion recombination factor.
Abstract: High dose-rate radiotherapy, known as FLASH, has been shown to increase the differential response between healthy and tumour tissue. Moreover, Very High Energy Electrons (VHEEs) provide more favourable dose distributions than conventional radiotherapy electron and photon beams. Plane-parallel ionisation chambers are the recommended secondary standard systems for clinical reference dosimetry of electrons, therefore chamber response to these high energy and high dose-per-pulse beams must be well understood. Graphite calorimetry, the UK primary standard, has been employed to measure the dose delivered from a 200 MeV pulsed electron beam. This was compared to the charge measurements of a plane-parallel ionisation chamber to determine the absolute collection efficiency and infer the ion recombination factor. The dose-per-pulse measured by the calorimeter ranged between 0.03 Gy/pulse and 5.26 Gy/pulse, corresponding to collection efficiencies between 97% and 4%, respectively. Multiple recombination models currently available have been compared with experimental results. This work is directly applicable to the development of standard dosimetry protocols for VHEE radiotherapy, FLASH radiotherapy and other high dose-rate modalities. However, the use of secondary standard ionisation chambers for the dosimetry of high dose-per-pulse VHEEs has been shown to require large corrections for charge collection inefficiency.

Journal ArticleDOI
TL;DR: In this article, the advantages, challenges, recent progress and future optimisation directions of various electrolytes for monovalent and multivalent ions batteries (i.e., organic, ionic liquid and aqueous liquid electrolytes, polymer and inorganic solid electrolytes) are summarized to guide the practical application for grid-oriented batteries.

Journal ArticleDOI
TL;DR: The OpenDose collaboration produced SAFs for all source region and target combinations of the 2 International Commission on Radiological Protection Publication 110 adult reference models in good agreement at all energies, with SDs below individual statistical uncertainties.
Abstract: Radiopharmaceutical dosimetry depends on the localization in space and time of radioactive sources and requires the estimation of the amount of energy emitted by the sources deposited within targets. In particular, when computing resources are not accessible, this task can be performed using precomputed tables of specific absorbed fractions (SAFs) or S values based on dosimetric models. The aim of the OpenDose collaboration is to generate and make freely available a range of dosimetric data and tools. Methods: OpenDose brings together resources and expertise from 18 international teams to produce and compare traceable dosimetric data using 6 of the most popular Monte Carlo codes in radiation transport (EGSnrc/EGS++, FLUKA, GATE, Geant4, MCNP/MCNPX, and PENELOPE). SAFs are uploaded, together with their associated statistical uncertainties, in a relational database. S values are then calculated from monoenergetic SAFs on the basis of the radioisotope decay data presented in International Commission on Radiological Protection Publication 107. Results: The OpenDose collaboration produced SAFs for all source region and target combinations of the 2 International Commission on Radiological Protection Publication 110 adult reference models. SAFs computed from the different Monte Carlo codes were in good agreement at all energies, with SDs below individual statistical uncertainties. Calculated S values were in good agreement with OLINDA/EXM 2.0 (commercial) and IDAC-Dose 2.1 (free) software. A dedicated website (www.opendose.org) has been developed to provide easy and open access to all data. Conclusion: The OpenDose website allows the display and downloading of SAFs and the corresponding S values for 1,252 radionuclides. The OpenDose collaboration, open to new research teams, will extend data production to other dosimetric models and implement new free features, such as online dosimetric tools and patient-specific absorbed dose calculation software, together with educational resources.

Journal ArticleDOI
TL;DR: The integration of multiple analytical modalities through this universal sample preparation protocol offers the ability to study tissues at a systems biology level and directly linking results to tissue morphology and cellular phenotype.
Abstract: A new tissue sample embedding and processing method is presented that provides downstream compatibility with numerous different histological, molecular biology, and analytical techniques. The methodology is based on the low temperature embedding of fresh frozen specimens into a hydrogel matrix composed of hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) and sectioning using a cryomicrotome. The hydrogel was expected not to interfere with standard tissue characterization methods, histologically or analytically. We assessed the compatibility of this protocol with various mass spectrometric imaging methods including matrix-assisted laser desorption ionization (MALDI), desorption electrospray ionization (DESI) and secondary ion mass spectrometry (SIMS). We also demonstrated the suitability of the universal protocol for extraction based molecular biology techniques such as rt-PCR. The integration of multiple analytical modalities through this universal sample preparation protocol offers the ability to study tissues at a systems biology level and directly linking results to tissue morphology and cellular phenotype.

Journal ArticleDOI
TL;DR: The authors show that in contrast to predictions the skyrmion Hall angle is independent of their diameter and motion is dominated by disorder and skyrMion-skyrmions interactions in the system.
Abstract: Magnetic skyrmions are topologically non-trivial nanoscale objects. Their topology, which originates in their chiral domain wall winding, governs their unique response to a motion-inducing force. When subjected to an electrical current, the chiral winding of the spin texture leads to a deflection of the skyrmion trajectory, characterised by an angle with respect to the applied force direction. This skyrmion Hall angle is predicted to be skyrmion diameter-dependent. In contrast, our experimental study finds that the skyrmion Hall angle is diameter-independent for skyrmions with diameters ranging from 35 to 825 nm. At an average velocity of 6 ± 1 ms−1, the average skyrmion Hall angle was measured to be 9° ± 2°. In fact, the skyrmion dynamics is dominated by the local energy landscape such as materials defects and the local magnetic configuration. Magnetic skyrmions are promising objects for future spintronic devices. However, a better understanding of their dynamics is required. Here, the authors show that in contrast to predictions the skyrmion Hall angle is independent of their diameter and motion is dominated by disorder and skyrmion-skyrmion interactions in the system.

Journal ArticleDOI
TL;DR: The demonstrated technique provides an alternative way to generate broadband microcombs and enables the selective enhancement of optical power in specific parts of a comb spectrum.
Abstract: Broadband optical frequency combs are extremely versatile tools for precision spectroscopy, ultrafast ranging, as channel generators for telecom networks, and for many other metrology applications. Here, we demonstrate that the optical spectrum of a soliton microcomb generated in a microresonator can be extended by bichromatic pumping: one laser with a wavelength in the anomalous dispersion regime of the microresonator generates a bright soliton microcomb while another laser in the normal dispersion regime both compensates the thermal effect of the microresonator and generates a repetition-rate-synchronized second frequency comb. Numerical simulations agree well with experimental results and reveal that a bright optical pulse from the second pump is passively formed in the normal dispersion regime and trapped by the primary soliton. In addition, we demonstrate that a dispersive wave can be generated and influenced by cross-phase-modulation-mediated repetition-rate synchronization of the two combs. The demonstrated technique provides an alternative way to generate broadband microcombs and enables the selective enhancement of optical power in specific parts of a comb spectrum.

Journal ArticleDOI
28 Oct 2020
TL;DR: Theoretical models used to describe the proton-conductive membrane in polymer electrolyte membrane fuel cells (PEMFCs) are reviewed, within the specific context of practical, physicochemical simulations of PEMFC device-scale performance and macroscopically observable behaviour.
Abstract: Theoretical models used to describe the proton-conductive membrane in polymer electrolyte membrane fuel cells (PEMFCs) are reviewed, within the specific context of practical, physicochemical simulations of PEMFC device-scale performance and macroscopically observable behaviour. Reported models and their parameterisation (especially for Nafion 1100 materials) are compiled into a single source with consistent notation. Detailed attention is given to the Springer-Zawodzinski-Gottesfeld, Weber-Newman, and "binary friction model" methods of coupling proton transport with water uptake and diffusive water transport; alongside, data are compiled for the corresponding parameterisation of proton conductivity, water sorption isotherm, water diffusion coefficient, and electroosmotic drag coefficient. Subsequent sections address the formulation and parameterisation of models incorporating interfacial transport resistances, hydraulic transport of water, swelling and mechanical properties, transient and non-isothermal phenomena, and transport of dilute gases and other contaminants. Lastly, a section is dedicated to the formulation of models predicting the rate of membrane degradation and its influence on PEMFC behaviour.

Journal ArticleDOI
TL;DR: It is demonstrated that no information on the thickness can be extracted from the shape of the 2D peak as this type of graphene is defective, and the Raman analysis provides guidance for the community on how to get information on defects coming from electrolyte, temperature and other experimental conditions, by making Raman spectroscopy a powerful metrology tool.
Abstract: Electrochemical exfoliation is one of the most promising methods for scalable production of graphene. However, limited understanding of its Raman spectrum as well as lack of measurement standards f...

Journal ArticleDOI
TL;DR: In this paper, a high-speed sintering additive manufacturing benchmarking artefact has been designed and characterised using a design-for-metrology approach, where the specifications and operating principles of the instruments that would be used to measure the manufactured artefact were taken into account during its design process.
Abstract: We present the design and characterisation of a high-speed sintering additive manufacturing benchmarking artefact following a design-for-metrology approach. In an important improvement over conventional approaches, the specifications and operating principles of the instruments that would be used to measure the manufactured artefact were taken into account during its design process. With the design-for-metrology methodology, we aim to improve and facilitate measurements on parts produced using additive manufacturing. The benchmarking artefact has a number of geometrical features, including sphericity, cylindricity, coaxiality and minimum feature size, all of which are measured using contact, optical and X-ray computed tomography coordinate measuring systems. The results highlight the differences between the measuring methods, and the need to establish a specification standards and guidance for the dimensional assessment of additive manufacturing parts.

Journal ArticleDOI
TL;DR: The International Society of Ultrasound in Obstetrics and Gynecology has compiled the following expert-opinion-based guidance for the performance of ultrasound investigations in pregnancy and for gynecological indications.
Abstract: In view of the challenges of the current coronavirus (COVID-19) pandemic and to protect both patients and ultrasound providers (physicians, sonographers, allied professionals), the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) has compiled the following expert-opinion-based guidance for the performance of ultrasound investigations in pregnancy and for gynecological indications. The guidance assumes that robust local processes are in place for cleaning ultrasound equipment after each patient routinely, and gives specific recommendations for ultrasound examinations in suspected or confirmed cases of COVID-19.

Journal ArticleDOI
TL;DR: In this article, a generalised framework for resolving the electrochemistry-diffusion interface and modelling hydrogen transport near a crack tip is presented, where the adsorption and absorption kinetics are captured by means of Neumann-type generalised boundary conditions.

Journal ArticleDOI
TL;DR: In this article, a 40-year history of SF 6 atmospheric mole fractions measured at the Advanced Global Atmospheric Gases Experiment (AGAGE)monitoring sites, combined with archived air samples, was used to determine emissionestimates from 1978 to 2018.
Abstract: . We report a 40-year history of SF 6 atmospheric mole fractions measured at the Advanced Global Atmospheric Gases Experiment (AGAGE) monitoring sites, combined with archived air samples, to determine emission estimates from 1978 to 2018. Previously we reported a global emission rate of 7.3±0.6 Gg yr −1 in 2008 and over the past decade emissions have continued to increase by about 24 % to 9.04±0.35 Gg yr −1 in 2018. We show that changing patterns in SF 6 consumption from developed (Kyoto Protocol Annex-1) to developing countries (non-Annex-1) and the rapid global expansion of the electric power industry, mainly in Asia, have increased the demand for SF 6 -insulated switchgear, circuit breakers, and transformers. The large bank of SF 6 sequestered in this electrical equipment provides a substantial source of emissions from maintenance, replacement, and continuous leakage. Other emissive sources of SF 6 occur from the magnesium, aluminium, and electronics industries as well as more minor industrial applications. More recently, reported emissions, including those from electrical equipment and metal industries, primarily in the Annex-1 countries, have declined steadily through substitution of alternative blanketing gases and technological improvements in less emissive equipment and more efficient industrial practices. Nevertheless, there are still demands for SF 6 in Annex-1 countries due to economic growth, as well as continuing emissions from older equipment and additional emissions from newly installed SF 6 -insulated electrical equipment, although at low emission rates. In addition, in the non-Annex-1 countries, SF 6 emissions have increased due to an expansion in the growth of the electrical power, metal, and electronics industries to support their continuing development. There is an annual difference of 2.5–5 Gg yr −1 (1990–2018) between our modelled top-down emissions and the UNFCCC-reported bottom-up emissions (United Nations Framework Convention on Climate Change), which we attempt to reconcile through analysis of the potential contribution of emissions from the various industrial applications which use SF 6 . We also investigate regional emissions in East Asia (China, S. Korea) and western Europe and their respective contributions to the global atmospheric SF 6 inventory. On an average annual basis, our estimated emissions from the whole of China are approximately 10 times greater than emissions from western Europe. In 2018, our modelled Chinese and western European emissions accounted for ∼36 % and 3.1 %, respectively, of our global SF 6 emissions estimate.