Space Resolution Research Articles

Embedded Distributed Temperature Sensing Enabled Multistate Joint Observation of Smart Lithium-Ion Battery

Accurate monitoring of the internal statuses is highly valuable for the management of the lithium-ion battery (LIB). This article proposes a thermal-model-based method for multistate joint observation, enabled by a novel smart battery design with an embedded and distributed temperature sensor. In particular, a novel smart battery is designed by implanting the distributed fiber optical sensor internally and externally. This promises a real-time distributed measurement of LIB internal and surface temperature with a high space resolution. Following this endeavor, a low-order joint observer is proposed to coestimate the thermal parameters, heat generation rate, state of charge, and maximum capacity. Experimental results disclose that the smart battery has space-resolved self-monitoring capability with high reproducibility. With the new sensing data, the heat generation rate, state of charge, and maximum capacity of LIB can be observed precisely in real time. The proposed method validates to outperform the commonly-used electrical-model-based method regarding the accuracy and the robustness to battery aging.

Location disaggregation for zone based travel plans

Activity-based models predict locations at TAZ (travel analysis zone) level. Recent research questions about carpooling, ride sharing, vehicle sharing, multi-modality, MaaS, . require space resolution at street address level. Pitfalls related to spatial resolution adaptation are identified and a disaggregation method beyond sampling from uniform distributions is presented. Daily travel plans generated by the FEATHERS activity based model for The Netherlands are presented and compared to observations.

Flares detected in ALMA single-dish images of the Sun

Context. The millimeter and submillimeter radiation of solar flares is poorly understood. Without spatial resolution, millimeter emission cannot be easily compared to flare emission in other wavelengths. Though the Atacama Large Millimeter-submillimeter Array (ALMA) offers sufficient resolution for the first time, ALMA cannot be used on demand to observe when a flare occurs, and when used as an interferometer, its field of view is smaller than an active region. Aims. We used readily available large-scale single-dish ALMA observations of solar millimeter flares and compared them to well-known features observed in other wavelengths. The properties of these other flare emissions, correlating in space and time, could then be used to interpret the millimeter brightenings and vice versa. The aim is to obtain reliable associations limited by the time and space resolution of single-dish observations. Methods. Ordinary interferometric ALMA observations require single-dish images of the full Sun for calibration. We collected such observations at 3 mm and 1 mm and searched for millimeter brightenings during times listed in a flare catalog. Results. All of the flares left a signature in millimeter waves. We found five events with nine or more images that could be used for comparison in time and space. The millimeter brightenings are associated with a variety of flare features in cool (Hα, 304 Å), intermediate (171 Å), and hot (94 Å) lines. In several cases, the millimeter brightening peaked at the footpoint of a hot flare loop. In other cases the peak of the millimeter brightening coincided with the top or footpoint of an active Hα filament. We also found correlations with post-flare loops and the tops of a hot loop. In some images, the millimeter radiation peaked at locations where no feature in the selected lines was found. Conclusions. The wide field of view provided by the single-dish ALMA observations allowed for a complete overview of the flare activity in millimeter waves for the first time. The associated phenomena often changed in type and location during the flare. The variety of phenomena detected in these millimeter observations may explain the sometimes bewildering behavior of millimeter flare emissions previously observed without spatial resolution.

Performance of improved RPCs demonstrator for the CMS at the HL-LHC

With the increase of the LHC luminosity foreseen in the coming years, components of detectors currently used in the LHC need to be replaced or new ones should be added. The new ones should be capable not only to support the high particle rate, but also to provide time information to reduce the data ambiguity due to the expected high pileup. The CMS collaboration have shown that the RPCs, using smaller gas gap (1.4 mm) and low-resistivity High Pressure Laminate, can stand rates of few kHz/cm2. They are equipped with new electronics sensitive to low signal charges. The electronics was developed to read out the RPC detectors from both sides of a strip and, using timing information, to identify the position along it. The excellent relative resolution of 160 ps leads to a space resolution of 1.5 cm. The absolute time measurement, determined by RPC signal around 500 ps, will also reduce the data ambiguity due to the expected high pileup at the Level 1 trigger. An engineering prototype of the final chamber was qualified in test beams at the Gamma Irradiation Facility (GIF++), located on one of the SPS beam lines at CERN. In addition, 4 demonstrator chambers have just been installed in the CMS cavern. This paper will present the results of the tests done in GIF++, as well as brand new results from the demonstrator chambers.

Probing charge density in materials with atomic resolution in real space

Probing charge density in materials with atomic resolution in real space

In operando measurements of high explosives.

In operando studies of high explosives involve dynamic extreme conditions produced as a shock wave travels through the explosive to produce a detonation. Here, we describe a method to safely produce detonations and dynamic extreme conditions in high explosives and in inert solids and liquids on a tabletop in a high-throughput format. This method uses a shock compression microscope, a microscope with a pulsed laser that can launch a hypervelocity flyer plate along with a velocimeter, an optical pyrometer, and a nanosecond camera that together can measure pressures, densities, and temperatures with high time and space resolution (2ns and 2 µm). We discuss how a detonation builds up in liquid nitromethane and show that we can produce and study detonations in sample volumes close to the theoretical minimum. We then discuss how a detonation builds up from a shock in a plastic-bonded explosive (PBX) based on HMX (1,3,5,7-Tetranitro-1,3,5,7-tetrazocane), where the initial steps are hotspot formation and deflagration growth in the shocked microstructure. A method is demonstrated where we can measure thermal emission from high-temperature reactions in every HMX crystal in the PBX, with the intent of determining which configurations produce the critical hot spots that grow and ignite the entire PBX.

Classification and Reconstruction of single and multiple ELVES in AUGER

ELVES have been regularly studied since 2013 with the twenty-four telescopes of the Pierre Auger Observatory, exploiting a dedicated trigger and extended readout. A large fraction of the observed events shows double ELVES within the time window, and, in some cases, even more complex structures are observed. We classify double ELVES using the radial variation of the time gap and the photon flux ratio between flashes. Such parameters may be related to the different types of lightning in which they originated. We will review the cross correlations of the ELVES light emissions with the radio waves detected by the antennas of the ENTLN network, active in Argentina since late 2018. Further improvements of our detection and classification algorithms were achieved by detecting ELVES from closer lightning: since December 2020, the ELVES trigger was extended to the three High Elevation Auger Telescopes (HEAT), which observe the night sky at elevation angles between 30 and 60 degrees, with an enhanced time resolution (50 ns time binning). Both single and double ELVES are recorded with unprecedented time and space resolution. Events from the first year of data taking will be shown.

Оценка обеспеченности зеленой инфраструктурой жителей арк­тического города (на примере Надыма)

Based on remote sensing data, the authors consider the features of the formation and use of green spaces in the city of Nadym (Yamalo-Nenets Autonomous Area). They give a detailed assessment of the availability of green infrastructure for the inhabitants of Nadym based on a comparison of the spatial distribution of vegetation and the urban population. During the construction of the city, there was a dramatic reduction in the area of vegetation cover, which reached its maximum during active construction in the 1980s. After the completion of the main construction stage and until now, there has been a steady increase in the share of vegetation, which is explained by active landscaping activities against the backdrop of climate softening. The authors have find out that while maintaining the high availability of open green spaces within the city, the main lack of vegetation is observed within the residential development of microdistricts. The methodology for the integrated use of medium and ultra-high resolution space images, UAV surveys, detailed mapping of residential buildings and field geobotanical descriptions tested during the study can be used in a detailed analysis of the state of the green infrastructure of other cities in the north of Western Siberia. In general, the assessment of the green infrastructure availability in the Arctic cities is of great importance for urban planning, allowing to fully take into account the regional environmental needs of local residents, in the context of the heterogeneity of their distribution.

Path Sampling Simulations Reveal How the Q61L Mutation Alters the Dynamics of KRas.

Flexibility is essential for many proteins to function, but can be difficult to characterize. Experiments lack resolution in space and time, while the time scales involved are prohibitively long for straightforward molecular dynamics simulations. In this work, we present a multiple state transition path sampling simulation study of a protein that has been notoriously difficult to characterize in its active state. The GTPase enzyme KRas is a signal transduction protein in pathways for cell differentiation, growth, and division. When active, KRas tightly binds guanosine triphosphate (GTP) in a rigid state. The protein-GTP complex can also visit more flexible states, in which it is not active. KRas mutations can affect the conversion between these rigid and flexible states, thus prolonging the activation of signal transduction pathways, which may result in tumor formation. In this work, we apply path sampling simulations to investigate the dynamic behavior of KRas-4B (wild type, WT) and the oncogenic mutant Q61L (Q61L). Our results show that KRas visits several conformational states, which are the same for WT and Q61L. The multiple state transition path sampling (MSTPS) method samples transitions between the different states in a single calculation. Tracking which transitions occur shows large differences between WT and Q61L. The MSTPS results further reveal that for Q61L, a route to a more flexible state is inaccessible, thus shifting the equilibrium to more rigid states. The methodology presented here enables a detailed characterization of protein flexibility on time scales not accessible with brute-force molecular dynamics simulations.

D-TransT: Deformable Transformer Tracking

The tracker based on the Siamese network describes the object-tracking task as a similarity-matching problem. The Siamese network is the current mainstream model. It achieves similarity learning by applying correlation filters to the target and search branches’ convolution features. However, because the correlation operation uses a local linear matching process, semantic information is lost, and it is simple to run into the issue of local optimality. Transformer Tracking has recently been proposed using an attention-based feature fusion network instead of the previous correlation operation to achieve excellent results. However, it only uses limited feature space resolution. Because of the limitations of the Transformer module, the network’s convergence is also very slow. We propose Deformable Transformer Tracking (D-TransT) which employs a deformable attention module that pre-filters for prominent key elements among all feature map pixels using a small set of sampling locations, and this module can be naturally extensible to aggregating multi-scale features. D-TransT can have faster convergence and better prediction than Transformer Tracking. D-TransT improves the convergence speed by 29.4% and achieves 65.6%, 73.3%, and 69.1% in AUC, PNorm and P, respectively. The experimental results demonstrate that the proposed tracker performs better than the most state-of-the-art algorithm.

Non-Invasive 3D Photoacoustic Tomography of Angiographic Anatomy and Hemodynamics of Fatty Livers in Rats.

Non-alcoholic fatty liver disease is the most common liver disorder worldwide, which strongly correlates to obesity, diabetes, and metabolic syndromes. Complementary to mainstream liver diagnostic modalities, photoacoustic tomography (PAT) can provide high-speed images with functional optical contrast. However, PAT has not been demonstrated to study fatty liver anatomy with clear volumetric vasculatures. The livers of multiple rats are non-invasively imaged in vivo using the recently developed 3D PAT platform. The system provides isotropically high spatial resolution in 3D space, presenting clear angiographic structures of rat livers without injecting contrast agents. Furthermore, to quantitatively analyze the difference between the livers of lean and obese rats, the authors measured several PAT features and statistical differences between the two groups are observed. In addition to the anatomy, a time-gated strategy is applied to correct respiration-induced motion artifacts and extracted the hemodynamics of major blood vessels during the breathing cycles. This study demonstrates the capabilities of 3D-PAT to reveal both angiographic anatomy and function in rat livers, providing hematogenous information for fatty liver diagnosis. 3D-PAT, as a new tool for preclinical research, warrants further improvements to be transferred to human pediatric liver imaging.

Near real-time mapping of burned area by synergizing multiple satellites remote-sensing data

ABSTRACT Wildfires have significant impacts on human lives, critical infrastructures, and Earth’s ecosystems. Accurate and timely information on burned area (BA) affected by wildfires is vital to better understand the drivers of wildfire events, as well as its relevance for biogeochemical cycles, climate, and air quality, and to aid wildfire management. Single satellite data have been used to detect the characteristics of wildfires, retrospectively mapping BAs at a variety of spatial resolutions in previous studies. However, due to the trade-off between spatial and temporal resolutions, single-source satellite data are not sufficient to characterize the explicit dynamics of BAs at high resolutions in both space and time. Thus, a two-stage near real-time BA mapping method was developed in this study to take advantage of the high temporal frequency of coarse resolution sensors and the fine spatial resolution of medium resolution sensors in BA mapping by synergizing freely available coarse and medium spatial resolution (MSR) sensors. First, high temporal frequency sensors such as MODIS and VIIRS were used to identify wildfires and potential BAs. Then, multiple MSR sensors such as Sentinel-2A/2B, Landsat OLI, and Resourcesat AWiFS were synthesized for extracting the BAs with more spatial details in near real-time. We applied the method in California, USA, where wildfires occurred in northern and southern parts in 2017. The results showed that the proposed method is promising for BA mapping with an overall accuracy of 0.84 and 0.85 for wildfires in northern and southern California, respectively. Additionally, the proposed method greatly improved the frequency and reduced the latency, with an average interval of 3.5 days (3 days) and latency of 4 days (sub-daily) for wildfires in southern (northern) California. The extracted BAs illustrated accurate spatial details with MSR sensors. Our method can significantly take advantage of multi-source remote-sensing observations to accurately map the BAs of active wildfires in near real-time. More importantly, the method can be applied to other geographic regions where wildfires risk humans and ecosystems.

4D-tracking in the 10-ps range: A technological perspective

The present paper focuses on recent and ready-to-come advancements concerning high-resolution 4D-tracking with a perspective approach. Four-dimensional-tracking techniques (particle tracking with timing information for each detection point) have revealed a necessity for the next and next-to-next generations of high-energy physics experiments to cope with the increasing luminosity and consequent event pile-up in the beam collision region. Such a decisive challenge concerns both detection and processing technologies at an unprecedented level of difficulty. In addition to the high performance required in space–time measurement precision (some tens of picoseconds resolution in timing and about 10 µm resolution in space), an extremely high radiation hardness is demanded for such technologies together with an extremely high read-out and processing capability. Emerging experimental solutions for sensors and electronics against such challenges are presented here.

Spectral resolutions in effect algebras

Effect algebras were introduced as an abstract algebraic model for Hilbert space effects representing quantum mechanical measurements. We study additional structures on an effect algebraEthat enable us to define spectrality and spectral resolutions for elements ofEakin to those of self-adjoint operators. These structures, called compression bases, are special families of maps onE, analogous to the set of compressions on operator algebras, order unit spaces or unital abelian groups. Elements of a compression base are in one-to-one correspondence with certain elements ofE, called projections. An effect algebra is called spectral if it has a distinguished compression base with two special properties: the projection cover property (i.e., for every elementainEthere is a smallest projection majorizinga), and the so-called b-comparability property, which is an analogue of general comparability in operator algebras or unital abelian groups. It is shown that in a spectral archimedean effect algebraE, everya∈Eadmits a unique rational spectral resolution and its properties are studied. If in additionEpossesses a separating set of states, then every elementa∈Eis determined by its spectral resolution. It is also proved that for some types of interval effect algebras (with RDP, archimedean divisible), spectrality ofEis equivalent to spectrality of its universal group and the corresponding rational spectral resolutions are the same. In particular, for convex archimedean effect algebras, spectral resolutions inEare in agreement with spectral resolutions in the corresponding order unit space.

A Correct Benchmark Problem of a Two-Dimensional Droplet Deformation in Simple Shear Flow

In this article, we numerically investigate a two-dimensional (2D) droplet deformation and breakup in simple shear flow using a phase-field model for two-phase fluid flows. The dominant driving force for a droplet breakup in simple shear flow is the three-dimensional (3D) phenomenon via surface tension force and Rayleigh instability, where a liquid cylinder of certain wavelengths is unstable against surface perturbation and breaks up into individual droplets to reduce the total surface energy. A 2D droplet breakup does not occur except in special cases because there is only one curvature direction of the droplet interface, which resists breakup. However, there have been many numerical simulation research works on the 2D droplet breakups in simple shear flow. This study demonstrates that the 2D droplet breakup phenomenon in simple shear flow is due to the lack of space resolution of the numerical grid.

Semi-supervised learning based framework for urban level building electricity consumption prediction

The spatial feature of building energy consumption in a city is essential for urban level energy planning and policy making. With the increasing availability of urban level building energy benchmarking datasets, machine learning has shown a powerful capability of making data-driven predictions on urban level building energy consumption. However, the building energy benchmarking datasets usually only cover large buildings, which are not sufficient representations of all buildings in a city. Besides building energy benchmarking datasets, many other urban level open datasets are also valuable to building energy prediction, but they do not contain building energy use data, in other words, they are unlabeled. This study proposes a novel framework based on semi-supervised learning to make effective use of the unlabeled datasets to develop more generic urban level data-driven building energy prediction models, and energy mapping with higher space resolution. The framework consists of preliminary labeling, selection of pseudo labeled samples and predictive modelling. Several machine learning algorithms are proposed and compared for generating pseudo labels of building electricity consumption for unlabeled datasets of small and medium-sized buildings. A selection process consisting of convergence testing and screening is designed to select pseudo labeled samples with high credibility to enlarge the labeled dataset. A novel two-level performance evaluation method is proposed to evaluate the performance of the framework at both urban level and district level to enhance the spatial resolution of the predictions. The framework is implemented to model and map the individual electricity consumptions of all buildings in two years in the districts of New York City using multiple open datasets. The results show significant improvement in terms of prediction accuracy at both levels. In addition, the applicability of the model to various buildings in the city is remarkably enhanced.

Twin Strouhal numbers in pressure loading of circular cylinder at high Reynolds numbers

We present a wind tunnel experiment on a large smooth circular cylinder mounted between walls. The Reynolds number range of interest is [800 000 – 2 170 000]. This low supercritical regime is often encountered in wind engineering applications, especially the excitation of flexible circular structures by vortex shedding. Main measurements are the unsteady wall pressure distributions around the cylinder by means of synchronized pressure taps with high resolution in time and space. By using the bi-orthogonal decomposition of this set of signals, twin Strouhal numbers are detected which correspond to the second and the fourth terms of the decomposition. These terms are found to produce the unsteady lift on the cylinder with a main contribution of the second one for which the associated Strouhal number is close to the one usually found at subcritical Reynolds numbers.

Signal formation and sharing in AC-LGADs using the ALTIROC 0 front-end chip

The development of detectors that provide high resolution in four dimensions has attracted wide-spread interest in the scientific community for applications in high-energy physics, nuclear physics, medical imaging, mass spectroscopy as well as quantum information. However, finding a technology capable of fulfilling such aspiration proved to be an arduous task. Among other silicon-based candidates, the Low-Gain Avalanche Diode (LGAD) has already shown excellent timing performances but proved to be unsuitable for fine pixelization. Therefore, the AC-coupled LGAD (AC-LGAD) approach was introduced to provide high resolution in both time and space, making it a promising candidate for future 4D detectors. However, appropriate readout electronics must be developed to match the sensor's fast-time and fine-pitch capabilities. This is currently a major technological challenge. In this paper, we test AC-LGAD prototypes read out by the fast-time ASIC ALTIROC 0, originally developed for the readout of DC-coupled LGADs for the ATLAS experiment at the High Luminosity-LHC. Signal generated by either betas from a 90Sr source or a focused infra-red laser were analyzed. This paper details the first successful readout of an AC-LGAD sensor using a readout chip. This result will pave the way for the design and construction of a new generation of AC-LGAD-based 4D detectors.

Mapping 2‐D Bedload Rates Throughout a Sand‐Bed River Reach From High‐Resolution Acoustical Surveys of Migrating Bedforms

AbstractThis paper introduces a method for determining spatially‐distributed, 2‐D bedload rates using repeat, high‐resolution surveys of the bed topography. As opposed to existing methods, bedform parameters and bedload rates are computed from bed elevation profiles interpolated along the local bedform velocities. The bedform velocity fields are computed applying Large‐Scale Particle Image Velocimetry, initially developed for surface velocity measurements, to pairs of successive Digital Elevation Models (DEMs). The bathymetry data are interpolated along the direction of each bedform velocity and the mean height of the closest bedform is computed. The dune shape factor is also evaluated along each bedform direction of travel. The local bedload fluxes can be computed by multiplying the bedform velocity by its mean height averaged over the successive two DEMs, and they can be time‐averaged over a series of DEM pairs. This method is applied to a high‐resolution acoustical survey of an approximately 300 m long by 40 m wide reach of the Colorado River in Grand Canyon upstream from Diamond Creek, USA. The repeat period was about 6–10 min and bed elevation was interpolated every 0.25 m. The obtained results provide insight to the spatial and temporal variability of bedload rates, bedform parameters and bedload fluxes through cross‐sections. The method can be applied to other repeated acoustical surveys of river reaches provided that the space and time resolutions are high enough to capture the local movement of bedforms.

Conceptual Design of a Scintillator-Based Fast-Ion Loss Detector for the Wendelstein 7-X Stellarator

A conceptual design of a scintillator-based fast-ion loss detector (FILD) has been developed for the Wendelstein 7-X stellarator (W7-X). Simulations using the Monte Carlo codes ASCOT5 and BEAMS3D have been performed to calculate the expected flux of neutral beam injection (NBI)-generated fast hydrogen ions onto the conceptual detector probe head. These fast-ion loss fluxes have been calculated for several magnetic field configurations as well as probe insertion positions. At the maximum insertion position, both co- and counter-going losses with high incident pitch angles are observed; however, at retracted positions, only co-going fast ions reach the probe head. The FILDSIM code has been used to optimize the geometry of the detector entrance and collimating elements to achieve a wide velocity space coverage as well as a high velocity–space resolution. A synthetic FILD signal is calculated for the expected loss distribution via forward modeling using the instrument response function. The synthetic signal is found to largely retain the velocity space features of the loss distribution.